Battery State Detection Using Transient Response Compensation
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Solution Overview
Problem
Existing battery state detection methods fail to accurately account for different reaction speeds within batteries, leading to inaccuracies in detecting residual capacity and state of health, particularly due to the influence of fast and slow reaction processes such as ion generation and diffusion.
Innovation Solution
A battery state detection method that evaluates the state of health (SOH) by considering the reaction speeds of ion generation and diffusion, using a mathematical model to compensate open circuit voltage (OCV) and calculate the state of charge (SOC) by integrating relaxation processes, represented by polynomial functions, to accurately reflect the battery's depletion level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the SOC is found from the OCV without reflecting the battery depletion condition, then the detection method is simple, but the accuracy of state detection drops
Solution Approach 1:
The patent performs preliminary action by measuring transient response during discharge/charge operations before the actual SOC detection. This preliminary measurement of transient response characteristics is stored and later used to correct the OCV-based SOC calculation, thereby improving accuracy without adding complexity to the main detection flow.
Solution Approach 2:
The patent introduces transient response characteristics as an intermediary element that mediates between the simple OCV measurement and the accurate SOC determination. The transient response serves as a bridge that provides depletion information to correct the OCV-based SOC calculation.
2Measurement precision
If discharge and charge are performed for a long period of time to measure long-term transient response, then slow reaction speed depletion can be detected, but the SOC changes during measurement making detection inaccurate
Solution Approach 1:
The patent applies partial action by measuring only a short-term transient response instead of waiting for complete convergence. This partial measurement captures the essential depletion characteristics without requiring the full long-term response, thereby avoiding SOC changes during measurement while still detecting slow reaction speed depletion.
Solution Approach 2:
The patent changes the measurement parameter from long-term transient response to short-term transient response. This parameter change allows the system to capture depletion information within a time frame where SOC remains relatively stable, eliminating the contradiction between measurement duration and accuracy.
3Productivity
If only short-period transient response is measured to detect fast reaction speed depletion, then the detection is quick, but slow reaction speed depletion cannot be detected
Solution Approach 1:
The patent segments the transient response measurement into multiple time periods - short-term for fast reaction speed depletion and long-term for slow reaction speed depletion. By analyzing different segments of the transient response curve, the system can detect both fast and slow depletion mechanisms without requiring a complete long-term measurement.
Solution Approach 2:
The patent uses periodic action by performing measurements at different time points during discharge/charge operations. Short-term measurements are taken periodically to capture fast reactions, while the system also captures long-term trends to detect slow reactions, thereby achieving comprehensive depletion detection through periodic sampling at different scales.
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
This method enables precise detection of battery states by accounting for varying reaction speeds, ensuring accurate residual capacity assessment and stable operation of electric devices, thereby enhancing safety and reducing environmental impact through improved idling stop function efficiency.
Implementation Method 1
the battery is affected respectively by ion generating and annihilating reactions on a surface of a polar plate due to electro-chemical reactions
Implementation Method 2
by moves of ions due to diffusion and convection of electrolytic solution
Implementation Method 3
by moves of ions due to diffusion and convection of electrolytic solution
Data Source
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AI summary
Problem to be solved: To provide a method for detecting a charged state of a battery, for evaluating a deterioration thereof due to each of reaction processes that individually have rates of reactions as different from therebetween, and for performing a detection of the charged state of the battery. Solution: The method for detecting the charged state of the battery according to the present invention comprises the steps of: measuring a voltage Vmes of the battery, an electric current Imes thereof and a temperature Tmes thereof, and then inputting such the measured values, as a step S1; judging whether or not an absolute value of the measured electric current as the Imes is smaller than a threshold value of the electric current as an Ithre, as a step S2; estimating an OCV20hr by making use of an SOCn-1 and an SOHn-1, that are the values after charging and/or discharging at the last time, with reference to a stable OCV estimated formula, as a step S4; calculating a difference between the measured value of the voltage as the Vmes and the OCV20hr, and then saving such the calculated value, as a step S5; renewing a relaxation function as an Fn(t) with corresponding to an amount of time as t, as processes from a step S6 through a step S19; calculating an SOHn at the step S17 with making use of the Fn(t) to be renewed; and calculating an SOCn at the step S19 with making use thereof.