Rolled-Ribbon Electrode Structure for Battery Power and Thermal Management
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Solution Overview
Problem
Existing electrochemical devices, such as batteries and fuel cells, face challenges in achieving high specific power and energy outputs per weight and volume due to internal resistance, limited interfacial contact area, and excessive heat generation, which reduces their efficiency and longevity.
Innovation Solution
The electrochemical device employs a rolled-ribbon cell configuration with alternating layers of electrodes and a thin ionic-conductive separator, where the electrodes are wound around a central axis to increase interfacial contact area and reduce internal resistance, and incorporates a housing with a pressure release mechanism to manage thermal and gas pressure safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If massive and/or large surface-area connections between electrodes and cell current collectors are provided, then internal resistance decreases and power output increases, but specific energy and power per weight are reduced
Solution Approach 1:
The patent transitions from planar electrode connections to three-dimensional serpentine pathways, allowing current to flow through multiple layers and surfaces. This dimensional expansion increases the effective contact area and reduces resistance without proportionally increasing the mass of current collectors, thereby improving power output while maintaining specific energy.
Solution Approach 2:
The serpentine current collector design nests multiple conductive pathways within the electrode structure itself, rather than using separate external connections. This integration reduces the overall mass of current collectors while providing extensive surface-area connections, resolving the contradiction between power output and specific energy per weight.
2Power
If high power output is achieved through increased current density, then energy delivery improves, but internal heat generation increases excessively
Solution Approach 1:
The patent extracts heat away from the internal electrode interfaces by providing dedicated thermal pathways through the serpentine current collectors and housing. This separates the heat generation site (electrode interfaces) from the heat accumulation zone, allowing high power output while controlling internal temperature through improved heat dissipation.
Solution Approach 2:
The serpentine current collector structure acts as an intermediary thermal management system, conducting heat away from critical electrode interfaces and distributing it through the housing. This mediator function allows high current density operation without excessive temperature rise at sensitive locations.
3Power
If the interfacial contact area between electrodes and electrolyte is increased, then ion conduction resistance decreases and power output increases, but device volume increases
Solution Approach 1:
The serpentine electrode configuration expands the interfacial contact area from a two-dimensional plane to a three-dimensional pathway that winds through the electrolyte. This allows the electrode to access electrolyte volume throughout the device, dramatically increasing effective contact area without proportionally increasing the device's external dimensions.
Solution Approach 2:
The serpentine (curved) electrode pathway maximizes the length of electrode surface in contact with electrolyte within a compact volume. The curved, winding path provides extensive interfacial area similar to how a coiled spring provides long length in small space, increasing power output without significant volume increase.
4Quantity of substance
If thin separator layers are used to reduce device thickness, then energy density improves, but mechanical strength and safety are compromised
Solution Approach 1:
The patent employs composite separator structures that combine thin separator layers with reinforcing elements or coatings. This composite approach maintains the low thickness required for high energy density while incorporating materials that provide the necessary mechanical strength and safety, resolving the contradiction between energy density and structural integrity.
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 significantly enhances power output by up to twenty times relative to cell capacity, achieves near theoretical power levels, and ensures safety through effective thermal management and pressure control, while maintaining high energy storage capacity and durability.
Implementation Method 1
a thin ionic-conductive separator, where the electrodes are wound around a central axis to increase interfacial contact area and reduce internal resistance
Implementation Method 2
The generated voltage per cell is predetermined by the electrochemical reaction of the component materials used
Implementation Method 3
the electrodes are wound around a central axis to increase interfacial contact area and reduce internal resistance
Implementation Method 4
incorporates a housing with a pressure release mechanism to manage thermal and gas pressure safely
Data Source
Figure 1~2
Figure 3~6
Figure 7~8
AI summary
An electrochemical device comprising alternating layers of positive and negative electrodes separated from each other by separator layers. The electrode layers extend beyond the periphery of the separator layers providing superior contact between the electrodes and battery terminals, eliminating the need for welding the electrode to the terminal. Electrical resistance within the battery is decreased and thermal conductivity of the cell is increased allowing for superior heat removal from the battery and increased efficiency. Increased internal pressure within the battery can be alleviated without damaging or removing the battery from service while keeping the contents of the battery sealed off from the atmosphere by a pressure release system. Nonoperative cells within a battery assembly can also be removed from service by shorting the nonoperative cell thus decreasing battery life.