Battery Fuel Gauges Using Cell Expansion for Accurate SOC and SOH
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems face challenges in accurately determining the state of charge (SOC) and state of health (SOH) of lithium-ion batteries, particularly those with silicon-containing electrodes, due to issues like hysteresis in charge/discharge curves and temperature effects.
Innovation Solution
The implementation of a battery fuel gauge system that utilizes expansion measurements, such as thickness, volume, or pressure changes, to determine the SOC and SOH of batteries. This system includes a processor that receives data from sensors and adjusts charging and discharging strategies based on the expansion data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electrical measurements are used to determine SOC and SOH, then the system is simple and easy to implement, but the measurement precision is insufficient due to hysteresis and temperature effects
Solution Approach 1:
The patent introduces expansion measurements (thickness, volume, or pressure changes) as an intermediary physical quantity to indirectly determine SOC and SOH. By measuring the physical expansion of the battery cell during charging and discharging cycles, the system obtains a more accurate indicator of state of charge and health that is less affected by hysteresis and temperature effects compared to direct electrical measurements alone.
Solution Approach 2:
The patent utilizes the physical parameter change (expansion) of the battery cell as a new measurement dimension. Instead of relying solely on electrical parameters (voltage, current), the system measures mechanical/physical parameters (thickness, volume, pressure) that change predictably with charge state, providing a more robust basis for SOC and SOH estimation.
2Measurement precision
If expansion measurements are used to determine SOC and SOH, then the measurement precision improves, but the device complexity increases due to additional sensors and processing
Solution Approach 1:
The patent makes the expansion measurement system multi-functional by using the same thickness, volume, or pressure measurements for multiple purposes: determining SOC, determining SOH, and monitoring battery health. This single measurement approach replaces what would otherwise require multiple separate sensing systems, thereby reducing overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The battery cell itself serves as the sensing element - its natural expansion and contraction during charge/discharge cycles provides the measurement signal. The cell's physical response to charging is harnessed as the measurement mechanism, eliminating the need for complex external sensing systems and reducing overall device complexity.
3Use of energy by moving object
If silicon-containing electrodes are used to increase capacity, then the energy density improves, but the measurement precision deteriorates due to significant expansion effects
Solution Approach 1:
The patent converts the harmful effect of significant expansion in silicon-containing electrodes into a beneficial measurement signal. Instead of treating the expansion as a source of measurement error, the system uses the expansion itself as the primary indicator for determining SOC and SOH. The larger the expansion, the more accurate the measurement, as the physical change is directly correlated with charge state.
Solution Approach 2:
The patent exploits the significant physical parameter changes (expansion) characteristic of silicon-containing electrodes by using these changes as the measurement basis. Rather than trying to measure small electrical signals that are obscured by the expansion effects, the system directly measures the expansion parameter, turning a previously problematic feature into the core measurement mechanism.
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 more accurate SOC and SOH estimates compared to traditional electrical measurements, leading to improved battery life management, reduced risk of overcharging or overdischarging, and enhanced performance and safety.
Implementation Method 1
a battery fuel gauge system that utilizes expansion measurements, such as thickness, volume, or pressure changes, to determine the SOC and SOH of batteries
Data Source
AI summary
In various embodiments, a battery fuel gauge includes a processor. The processor can be configured to obtain information relating to expansion of a battery and to determine a state of charge and/or a state of health of the battery based at least in part on the expansion of the battery. In certain embodiments, a battery management system can be configured to control charging/discharging and/or cooling/heating of one or more cells in the battery based at least in part on the expansion of the battery.