Battery State-of-Health Estimation via Controlled Current and Temperature Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for estimating the state-of-health of a battery module in electric vehicles are time-consuming, pose safety risks, require disassembly, and involve expensive high-frequency equipment, making them inconvenient and costly.
Innovation Solution
A device comprising a control module, correction module, and processing unit that controls the battery current to decrease voltage during a testing period, acquires temperature correction values, and estimates state-of-health using current and voltage variation values, eliminating the need for disassembly and dedicated high-frequency equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional discharge method is used to estimate state-of-health, then measurement can be performed, but it is time-consuming and poses safety risks
Solution Approach 1:
The patent performs preliminary charging to a target state before the actual measurement. By pre-charging the battery to a predetermined target during normal operation, the system prepares the battery in advance for the impedance measurement, eliminating the need for time-consuming discharge cycles while ensuring accurate state-of-health estimation
Solution Approach 2:
The patent skips the traditional lengthy discharge process by directly measuring impedance at a predetermined charging target. Instead of allowing the battery to fully discharge for measurement, the system rapidly performs impedance measurement at the charged state, rushing through the measurement process in a matter of seconds rather than hours
2Measurement precision
If conventional discharge method is used to estimate state-of-health, then measurement can be performed, but it poses safety risks
Solution Approach 1:
The patent skips the dangerous full discharge process by performing impedance measurement at a predetermined charging target. By measuring at the charged state rather than discharging to depletion, the system eliminates safety risks associated with deep discharge while maintaining measurement accuracy
Solution Approach 2:
The patent uses the battery's own charging process to achieve the measurement condition. Instead of requiring separate discharge testing, the system utilizes the existing charging operation to reach the target state, making the battery serve its own measurement needs without external stress that could compromise safety
3Measurement precision
If dedicated high-frequency measuring equipment is used, then internal resistance measurement is accurate, but it is expensive
Solution Approach 1:
The patent uses the existing charging current as a substitute for dedicated high-frequency measurement equipment. By utilizing the charging current already present in the system and measuring voltage response, the method creates a functional copy of impedance measurement capability without requiring expensive specialized instruments
Solution Approach 2:
The patent replaces complex high-frequency measurement hardware with a simpler electrical measurement approach. Instead of using dedicated high-frequency equipment, the system substitutes with standard voltage and current sensing during normal charging, eliminating the need for specialized mechanical or electronic measurement devices
4Measurement precision
If conventional methods are used to estimate state-of-health, then measurement can be performed, but disassembly is required
Solution Approach 1:
The patent enables the battery module to perform self-diagnosis during normal charging operation. By measuring impedance at a predetermined charging target using the battery's own charging current and voltage, the system eliminates the need for disassembly while maintaining measurement accuracy, allowing users to monitor battery health conveniently
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 precise state-of-health estimation without disassembly, reduces safety risks, and saves time and costs by directly controlling battery current and correcting voltage variations, improving estimation accuracy and user convenience.
Implementation Method 1
outputs, immediately after a beginning of a predetermined testing period at which the charging of the battery module has reached a predetermined target, a control signal for controlling a battery current flowing through the battery module to have a predetermined current value for the predetermined testing period, such that a battery voltage of the battery module decreases during the predetermined testing period
Implementation Method 2
acquire a voltage correction value according to a temperature value of the battery module during the predetermined test period
Data Source
AI summary
A device for estimating a state-of-health (SOH) of a battery module controls a battery current to have a predetermined current value for a testing period such that a battery voltage decreases during the testing period, corrects a voltage variation value of the battery module during the testing period according to a temperature value of the battery module, and estimates the SOH of the battery module according to the corrected voltage variation value, a current variation value of the battery module during the testing period, and a rated capacity of the battery module.