Tabless Lithium Battery Cell With Metallized Film Current Collectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium batteries face safety issues due to internal short circuits, which can lead to high temperature events, fires, and explosions, primarily caused by manufacturing defects, such as metallic particles, burrs, or misalignments, and are exacerbated by flammable organic solvents, with existing solutions like thermally stable separators offering limited effectiveness.
Innovation Solution
The use of thin metallized film current collectors with a polymeric substrate that becomes nonconductive upon exposure to high temperatures, acting as an internal fuse to break the conductive pathway during a short circuit, and a tabless structure that eliminates the need for welded tabs, allowing for direct contact between the current collector and the housing to enhance safety and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional thick current collectors are used, then structural strength and conductivity are maintained, but weight and volume increase
Solution Approach 1:
The current collector uses a composite structure consisting of a thin polymeric substrate combined with a metallized layer. The polymeric substrate provides mechanical strength and structural integrity, while the metallized layer provides electrical conductivity. This composite approach allows the current collector to be much thinner than traditional solid metal collectors while maintaining both strength and conductivity properties.
2Weight of moving object
If thin metallized film current collectors are used, then weight and volume are reduced, but safety against thermal runaway is compromised
Solution Approach 1:
The polymeric substrate material is selected to undergo a phase change at a specific temperature (between 100°C and 500°C). When exposed to high temperatures during thermal runaway events, the substrate melts or decomposes, causing the current collector to lose structural integrity and become nonconductive. This parameter change in the material properties at elevated temperatures automatically interrupts current flow and prevents further thermal runaway.
3Use of energy by moving object
If flammable organic electrolytes are used, then energy density is improved, but fire risk increases
Solution Approach 1:
The temperature-responsive polymeric substrate acts as an intermediary safety mechanism between the flammable electrolyte and the current collector. When the temperature rises to dangerous levels that could ignite the electrolyte, the substrate undergoes phase change and interrupts current flow, preventing the conditions necessary for fire. This intermediary mechanism allows the use of high-energy-density flammable electrolytes while automatically preventing fire hazards.
4Device complexity
If tabless structure is implemented, then manufacturing complexity is reduced, but electrical conductivity from internal portion to external access is worsened
Solution Approach 1:
Instead of using traditional tab extensions that protrude from the battery surface, the current collector is designed to extend through the entire thickness of the battery pack in the third dimension. The thin metallized film current collectors are arranged to provide continuous electrical pathways from the internal electrodes through the battery housing to external contact points, eliminating the need for separate tabs while maintaining conductivity.
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 solution significantly reduces the risk of thermal runaway and fire by immediately ceasing current flow upon a short circuit, maintaining safety while allowing for high power and conductivity without the weight and volume of traditional thick current collectors, and enables the use of flammable electrolytes without ignition risks.
Implementation Method 1
thin metallized film current collectors with a polymeric substrate that becomes nonconductive upon exposure to high temperatures, acting as an internal fuse to break the conductive pathway during a short circuit
Implementation Method 2
thin metallized film current collectors...provide both safety features with low thermal runaway potential, low internal resistance, and high thermal conductivity
Implementation Method 3
thin metallized film current collectors...provide both safety features with low thermal runaway potential, low internal resistance, and high thermal conductivity
Data Source
AI summary
A lithium battery cell with an internal fuse component without any welded tabs present for conductance from the internal portion thereof externally to power a subject device is provided. Disclosed herein are lithium ion (liquid electrolyte) battery configurations utilizing thin metallized film current collectors as conducting tabs that provide full electrical conductivity from one pole to another throughout the internal portions of the battery with sufficient space for liquid electrolyte flow as well. Such thin metallized film current collectors thus provide both safety features with low electrical charge runaway potential, low internal resistance, and high thermal conductivity with a simplified manner of providing external electrical conductivity simultaneously.