Electrochemical Cell Tab Layout for Accurate Series Voltage Sensing
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Solution Overview
Problem
Existing methods for monitoring and balancing electrochemical cells in series, such as in lithium-ion batteries, face challenges due to intra-electrode voltage gradients and the inability to simultaneously monitor and balance cells, leading to reduced performance and accuracy in voltage measurement and balancing.
Innovation Solution
The use of multiple anode and cathode tabs for direct measurement of voltage at different locations along the electrodes, allowing for simultaneous monitoring and balancing, and the inclusion of semi-solid electrodes with higher active material loadings and reduced tortuosity for improved charge capacity and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage is measured through the same electrical connection points used for current flow, then the measurement system is simplified, but voltage offset errors occur that reduce measurement precision
Solution Approach 1:
The patent divides the electrical connection system into separate functional components: current-carrying connection points and voltage-sensing connection points. By segmenting the measurement function from the current flow path, the system eliminates voltage offset errors caused by current flow while maintaining relatively simple overall system architecture.
Solution Approach 2:
The patent extracts the voltage sensing function from the current-carrying connection points and implements it through separate sensing electrodes or connection points. This extraction allows voltage measurement independent of current flow, eliminating the voltage offset error that would otherwise occur in the current path.
2Device complexity
If a single reference point is used for voltage measurement, then the measurement system is simplified, but intra-electrode voltage gradients reduce measurement accuracy
Solution Approach 1:
The patent segments the voltage measurement function into multiple spatially distributed sensing points across the electrode surface. This segmentation allows the system to capture voltage gradients and determine representative cell voltage more accurately, while the complexity is managed through systematic arrangement of the multiple sensing points.
Solution Approach 2:
The patent implements voltage sensing points that serve dual purposes: they function as both current collection points and voltage measurement points. This multi-functionality reduces overall system complexity while enabling accurate voltage measurement that accounts for intra-electrode gradients.
3Device complexity
If monitoring and balancing are conducted through the same connection points, then the system structure is simplified, but simultaneous monitoring and balancing cannot be performed
Solution Approach 1:
The patent segments the electrical connection system into distinct current-carrying pathways and voltage-sensing pathways. This segmentation enables simultaneous monitoring and balancing operations by allowing voltage measurement through sensing points while current flows through separate connection points, thereby improving operational efficiency without significantly increasing structural complexity.
Solution Approach 2:
The patent introduces voltage-sensing connection points as intermediary elements that enable voltage measurement without interrupting current flow. These intermediary sensing points facilitate simultaneous monitoring and balancing operations by providing a non-intrusive measurement path that does not interfere with the current-carrying function.
4Quantity of substance
If large-area electrodes are used to increase charge capacity, then energy density is improved, but intra-electrode voltage gradients increase that reduce monitoring accuracy
Solution Approach 1:
The patent applies segmentation by distributing multiple voltage-sensing points across the large-area electrode surface. This segmentation allows the system to measure and account for voltage gradients across the electrode, maintaining measurement accuracy despite the increased electrode area and corresponding charge capacity.
Solution Approach 2:
The patent implements local quality by placing voltage-sensing points at specific locations across the electrode surface where they can locally measure voltage conditions. This local measurement approach allows accurate characterization of voltage gradients across large-area electrodes, enabling precise monitoring of cells with high charge capacity.
Data Source
AI summary
In some aspects, a method of monitoring health of an electrochemical cell can include measuring a first anode voltage at a first anode tab from the plurality of anode tabs and a second anode voltage at a second anode tab from the plurality of anode tabs; measuring a first cathode voltage at a first cathode tab from the plurality of cathode tabs and a second cathode voltage at a second cathode tab from the plurality of cathode tabs; and calculating a first sense voltage, the first sense voltage being a difference between the first cathode voltage and the first anode voltage. In some embodiments, a second sense voltage can be calculated, the second sense voltage being a difference between the second cathode voltage and the second anode voltage. In some embodiments, a difference between the first sense voltage and the second sense voltage can be calculated.