Electrode Current Limiter Assembly for Thermal Runaway Prevention
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Solution Overview
Problem
Conventional two-dimensional lithium-based secondary batteries face safety issues due to thermal runaway risks from uncontrolled energy release during excessive current flow, which existing safety mechanisms like resettable or non-resettable fuses fail to address promptly, leading to potential battery failure or reduced capacity.
Innovation Solution
Incorporation of current limiters in three-dimensional electrode assemblies, where electrode current collectors are bent and adhered to a busbar through a resistive polymeric adhesive, allowing immediate current limitation independent of temperature changes, thereby preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuses (resettable or non-resettable) are used for safety, then thermal runaway risk is addressed, but the response is delayed due to temperature-dependent activation
Solution Approach 1:
The patent replaces thermal-mechanical fuse activation with an electronic control system that uses a microcontroller and MOSFET transistor to detect and respond to excessive current. The microcontroller monitors current through an operational amplifier and actively switches the MOSFET to limit current immediately, eliminating the thermal lag inherent in conventional fuses.
Solution Approach 2:
The patent implements a feedback control system where the microcontroller continuously monitors current flow through sensing circuitry (operational amplifier) and adjusts the MOSFET gate voltage accordingly. When excessive current is detected, the system provides feedback to the MOSFET to reduce conductivity and limit current, creating a closed-loop control that responds immediately without thermal delay.
2Quantity of substance
If three-dimensional electrode assemblies are used, then capacity and energy density are increased, but current control and thermal runaway prevention become more challenging
Solution Approach 1:
The patent divides the electrode assembly into multiple independent unit cells, each with its own current limiter circuit. This segmentation allows independent control of current in each cell, preventing thermal runaway from propagating across the entire assembly and enabling precise current management in high-capacity three-dimensional configurations.
Solution Approach 2:
The patent introduces MOSFET transistors as intermediary current-limiting devices between the power source and the electrode assembly. These MOSFETs act as controllable resistors that can rapidly adjust their conductivity to limit current flow, providing an intermediate control layer that manages current distribution in complex three-dimensional electrode structures.
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
The solution effectively limits current flow, preventing thermal runaway and enhancing battery safety by ensuring immediate response to excessive current, maintaining battery functionality and capacity.
Implementation Method 1
an adhesive layer comprising a resistive polymeric material... effectively limits current flow... immediate current limitation independent of temperature changes
Implementation Method 2
electrode current collectors are bent and adhered to a busbar through a resistive polymeric adhesive
Data Source
AI summary
A method includes stacking unit cells in a stacking direction. Each unit cell includes an electrode structure, a separator structure, and a counter-electrode structure. The electrode structure includes an electrode current collector and an electrode active material layer, and the counter-electrode structure includes a counter-electrode current collector and a counter-electrode active material layer. The electrode and counter-electrode structures extend in a longitudinal direction perpendicular to the stacking direction, and an end portion of the electrode current collector extends past the electrode active material and the separator structure in the longitudinal direction. The end portion of each electrode current collector is bent in a direction orthogonal to the longitudinal direction, an electrode busbar is positioned extending in the stacking direction with a surface adjacent the end portions, and heat and pressure are applied to the electrode busbar to adhere the end portions to the busbar through an adhesive layer.