Pouch Cell Surface Sensors for Accurate SoC and SoH Detection
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Solution Overview
Problem
Current methods for determining the State of Charge (SoC) and State of Health (SoH) of batteries face challenges due to high costs and interference from adhesives and substrates in non-invasive deformation measurements, particularly in bag-type batteries, which affect the accuracy and integration of sensors.
Innovation Solution
A battery cell with sensors directly deposited on the outside surface of the bag, using piezoresistive and thermoresistive materials for deformation and temperature sensing, connected in a Wheatstone bridge configuration, eliminates intermediate elements and reduces manufacturing costs, allowing for accurate SoC and SoH estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a deformation sensor is glued on the cell surface using conventional methods, then the sensor can be attached to the cell, but the glue acts as an insulator that interferes with the measurement of deformation, leading to errors
Solution Approach 1:
The patent merges the sensor elements directly with the cell surface by depositing sensing material, conducting material, and resistor material in separate layers directly onto the cell surface. This eliminates the need for separate adhesive layers and substrates, thereby removing the insulating barrier that caused measurement errors while simplifying the overall device structure.
Solution Approach 2:
The patent extracts and removes the intermediate elements (adhesive layers and substrates) from the sensor attachment process. By directly depositing functional materials onto the cell surface, the harmful insulating layer is completely eliminated, allowing direct contact between the sensor and cell surface for accurate deformation measurement.
2Measurement precision
If optical measurement methods are used to measure cell surface deformation, then deformation can be detected, but the method involves excessive cost and integration difficulty into the battery
Solution Approach 1:
The patent replaces complex optical measurement systems with a simple electrical resistance-based sensing system. The sensing element utilizes piezoresistive material whose electrical resistance changes with deformation, eliminating the need for expensive optical equipment while enabling direct integration into the battery structure through material deposition.
Solution Approach 2:
The patent changes the measurement parameter from optical properties to electrical resistance properties. By using piezoresistive material that changes electrical resistance in response to mechanical deformation, the system achieves accurate deformation measurement through simple electrical measurements rather than complex optical systems.
3Measurement precision
If electrical measurement methods are used to determine SoC and SoH, then battery impedance can be estimated, but the impedance is less than 1 mOhm requiring specialized hardware that substantially increases battery cost
Solution Approach 1:
The patent introduces an intermediary sensing element that indirectly measures battery impedance through deformation detection. Instead of directly measuring the small impedance values (<1 mOhm) which require specialized hardware, the piezoresistive sensor measures cell deformation during charge/discharge cycles, providing an indirect but accurate method to determine SoC and SoH without expensive specialized measurement equipment.
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 configuration provides accurate and cost-effective measurement of battery deformation and temperature, enhancing data acquisition and extending battery life by improving energy management.
Implementation Method 1
the sensing element is a deformation and/or temperature sensing element constituted by piezoresistive and/or thermoresistive material deposited on the outside surface of the bag
Implementation Method 2
the sensing element is a deformation and/or temperature sensing element constituted by piezoresistive and/or thermoresistive material deposited on the outside surface of the bag
Implementation Method 3
the sensing element, the conducting element and/or the resistor element are respectively obtained by separately depositing portions of material of the sensing element, of conducting element material or of the resistor element on the outside surface of the bag
Data Source
AI summary
Disclosed is an electrochemical cell in the form of a bag (1.1), constituting an electric battery (1), which comprises a sensor (2) fixed to the outside surface of the bag (1.1) and comprising: at least one sensing element (2.1.1, 2.1.2); at least one conducting element (3); and, optionally, at least one resistor element (2.2), the conducting element (3) connecting the sensing element (2.1) and/or the resistor element (2.2) together, wherein the sensing element, the conducting element (3) and/or the resistor element (2.2) are respectively obtained by separately depositing portions of material of the sensing element, of the conducting element (3) or of the resistor element (2.2) on the outside of the bag (1.1). Also disclosed is a battery comprising at least one electrochemical cell in the form of a bag (1.1).