Battery SOH Estimation via Ampere Counting Mapping
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Solution Overview
Problem
Existing methods for estimating the state of health (SOH) of batteries are inaccurate due to indirect measurement of internal resistance and prone to measurement errors, often requiring invasive procedures or complex calculations, which can lead to unreliable SOH estimation.
Innovation Solution
An apparatus and method that uses SOH-based ampere counting values obtained from ampere counting experiments to estimate battery health, calculating an arithmetic or weighted average of SOH values over time, allowing for accurate estimation without complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If internal resistance is indirectly calculated using Ohm's law from measured voltage and current, then the calculation is simple, but the measurement precision deteriorates due to IR drop effects and current measurement errors
Solution Approach 1:
The patent applies preliminary action by pre-establishing a mapping relationship between ampere counting values and SOH values through offline experiments. During actual operation, the system only needs to query the pre-established mapping table based on the calculated ampere counting value, avoiding complex real-time calculations and improving both speed and accuracy.
Solution Approach 2:
The patent introduces ampere counting value as an intermediary parameter between direct current measurement and SOH estimation. Instead of directly using current measurements (which are prone to errors) to calculate internal resistance, the system uses ampere counting values to query a pre-established mapping relationship, thereby indirectly obtaining SOH with higher precision.
2Measurement precision
If full discharge test is performed to estimate SOH, then the measurement precision is high, but the loss of energy increases and system operation is interrupted
Solution Approach 1:
The patent applies partial action by performing only the necessary ampere counting during normal charging or discharging operations to estimate SOH, rather than conducting a complete full discharge test. This partial measurement approach achieves sufficient precision without wasting battery energy or interrupting system operation.
Solution Approach 2:
The system uses the battery's own charging or discharging current during normal operation to perform ampere counting for SOH estimation. The battery serves itself by utilizing its operational current rather than requiring an external full discharge test, thereby avoiding energy waste and system interruption.
3Ease of operation
If ampere counting is performed during battery charging or discharging, then the measurement is noninvasive and does not interrupt system operation, but the accuracy deteriorates due to continuous accumulation of current measurement errors
Solution Approach 1:
The patent introduces ampere counting value as an intermediary that accumulates current measurements in a controlled manner. By using this intermediary parameter to query a pre-established mapping relationship rather than directly accumulating raw current measurements, the system reduces the impact of measurement errors and maintains higher accuracy.
Solution Approach 2:
The patent replaces the mechanical accumulation of current measurement errors with a computational approach using pre-established mapping relationships. Instead of directly integrating noisy current signals, the system uses a lookup table method that substitutes complex error-prone calculations with simpler queries, thereby improving accuracy.
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 approach provides a reliable and accurate estimation of battery health, enabling timely replacement and preventing over-charging or over-discharging, thereby improving battery safety and efficiency.
Implementation Method 1
a control unit calculates an ampere counting value by using charging or discharging current of the battery
Data Source
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AI summary
Disclosed is an apparatus and method for estimating state of health (SOH) of a battery. The apparatus for estimating state of health of a battery includes a sensing unit for measuring a battery voltage and current within a predetermined charging voltage range; a memory unit storing the battery voltage and current values measured by the sensing unit and SOH-based ampere counting values, obtained by an ampere counting experiment of a battery whose actual degradation degree is known; and a control unit for calculating an ampere counting value by counting the measured current values stored in the memory unit within the charging voltage range, and estimating a SOH value by mapping the SOH value corresponding to the calculated ampere counting value from the SOH-based ampere counting values stored in the memory unit.