Lithium-Ion Battery Endothermic Venting for Thermal Runaway
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Solution Overview
Problem
Existing lithium ion batteries face challenges in achieving high energy and power densities, safety, and cost-effectiveness, particularly in large format applications, due to issues such as mechanical stress, electrolyte starvation, complex assembly, weld failures, thermal runaway, and inefficient use of space.
Innovation Solution
A multi-core lithium ion battery structure with integrated bare current collectors and busbars, kinetic energy absorbing materials, and endothermic materials to manage heat and prevent thermal runaway, while eliminating tabs and liners to enhance safety and reduce production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple small cells are connected in arrays to achieve high energy and power densities, then the battery capacity increases, but the complexity of assembly and welding increases, leading to higher failure risk and manufacturing costs
Solution Approach 1:
The battery is divided into multiple independent core members (segments) that are connected in parallel within a single sealed enclosure. Each core member functions as an independent electrochemical cell with its own electrodes, electrolyte, and separator, allowing the battery to achieve high capacity through parallel connection while simplifying the overall assembly structure compared to connecting multiple separate small cells.
Solution Approach 2:
Multiple core members are combined within a single sealed enclosure sharing common electrolyte and atmosphere regions, eliminating the need for multiple separate enclosures and reducing assembly complexity. The current collectors and busbars are integrated to electrically connect multiple cores simultaneously, further simplifying the structure.
2Quantity of substance
If more active anode and cathode materials are inserted into a can of given volume to increase storage capacity, then the energy density increases, but mechanical stress on the electrodes increases, limiting cycle life
Solution Approach 1:
The battery is segmented into multiple independent core members, each containing its own electrode assemblies. This segmentation distributes the mechanical stress of electrode expansion and contraction across multiple smaller units rather than concentrating it in a single large cell, thereby maintaining electrode integrity and extending cycle life while achieving high total capacity.
Solution Approach 2:
Each core member is designed with optimized local electrode configurations and proportions of active materials tailored to its specific capacity requirements. This allows each segment to operate within optimal stress parameters while the aggregate system achieves high total capacity.
3Duration of action of stationary object
If the amount of electrolyte in small cells is increased to prevent electrolyte starvation, then the battery life improves, but the cell volume increases, reducing volumetric energy density
Solution Approach 1:
Multiple core members share a common electrolyte environment within a single sealed enclosure, allowing the electrolyte to be distributed across all cores simultaneously. This eliminates electrolyte starvation in each individual core while maintaining compact overall volume, as the electrolyte volume is shared rather than duplicated for each core.
Solution Approach 2:
The electrolyte serves multiple functions simultaneously: it provides ionic conduction pathways for all core members, acts as a shared reservoir that prevents starvation, and maintains a common chemical environment that enhances overall battery longevity. This multi-functional use of electrolyte maximizes battery life without proportionally increasing volume.
4Reliability
If complex welding patterns are created to minimize weld failures in small cell arrays, then the reliability improves, but the manufacturing cost and complexity increase
Solution Approach 1:
Multiple current collectors and busbars are integrated into a unified electrical connection structure that simultaneously connects multiple core members. This merging reduces the total number of individual weld joints required compared to connecting each core separately, thereby maintaining high reliability while simplifying the welding pattern and reducing manufacturing complexity.
Solution Approach 2:
The busbar structure serves multiple functions: it provides electrical connection for multiple cores, acts as a mechanical support structure, and facilitates simplified welding patterns. This multi-functionality reduces the overall complexity of the welding scheme while maintaining high connection reliability.
5Object-affected harmful factors
If proper packaging is used to prevent cascading thermal runaway in small cell arrays, then the safety improves, but the manufacturing cost increases
Solution Approach 1:
The battery is segmented into multiple independent core members within a single enclosure, creating natural thermal barriers between cores. This segmentation limits the propagation of thermal runaway events to individual cores or small groups, enhancing safety without requiring complex external packaging structures or additional safety components.
Solution Approach 2:
The sealed enclosure integrates multiple cores into a unified structure with shared electrolyte and atmosphere regions, creating a controlled environment that naturally limits thermal runaway propagation. This merging approach provides safety benefits without requiring additional packaging layers or safety components, thereby controlling manufacturing costs.
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 provides improved safety, reduced manufacturing costs, and increased energy density by optimizing power-to-energy ratios, managing thermal events, and preventing cascading thermal runaway.
Implementation Method 1
The support member includes a kinetic energy absorbing material. The kinetic energy absorbing material is formed of one of aluminum foam, ceramic, and plastic.
Implementation Method 2
endothermic materials to manage heat and prevent thermal runaway
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
Lithium ion batteries are provided that include materials that provide advantageous endothermic functionalities contributing to the safety and stability of the batteries. The endothermic materials may include a ceramic matrix incorporating an inorganic gas-generating endothermic material. If the temperature of the lithium ion battery rises above a predetermined level, the endothermic materials serve to provide one or more functions to prevent and/or minimize the potential for thermal runaway, e.g., thermal insulation (particularly at high temperatures); (ii) energy absorption; (iii) venting of gases produced, in whole or in part, from endothermic reaction(s) associated with the endothermic materials, (iv) raising total pressure within the battery structure; (v) removal of absorbed heat from the battery system via venting of gases produced during the endothermic reaction(s) associated with the endothermic materials, and/or (vi) dilution of toxic gases (if present) and their safe expulsion from the battery system.