Multi-Core Lithium Ion Battery Segmentation for Thermal Runaway Safety
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Solution Overview
Problem
Current lithium ion batteries face challenges in safety and manufacturing costs, particularly with large cells due to mechanical stress, electrolyte limitations, and costly safety measures, while small cells have limitations in assembly and safety concerns related to thermal runaway.
Innovation Solution
A multi-core lithium ion battery structure with a sealed enclosure containing kinetic energy absorbing materials and compartmentalized compartments to manage mechanical stress and thermal runaway, featuring a support member with cavities for core members and a shared atmosphere or distinct compartments for pressure management, along with electrical connectors and fire retardant materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large cells are used to increase battery capacity, then energy density is improved, but mechanical stress and safety risks increase
Solution Approach 1:
The battery is divided into multiple small cells arranged in a multi-core array configuration, with each cell independently housed in its own enclosure. This segmentation allows the battery to achieve large total capacity while maintaining the safety advantages of small individual cell sizes, as thermal runaway in one cell does not propagate to others.
Solution Approach 2:
A shared atmosphere region is introduced as an intermediary space between the individual cell enclosures. This region allows for pressure equalization and thermal management across the battery pack while maintaining physical separation between cells, thus managing both mechanical stress and thermal runaway risks.
2Reliability
If small cells are used to reduce mechanical stress, then safety is improved, but assembly complexity increases
Solution Approach 1:
Multiple individual cell enclosures are merged into a single integrated battery assembly with a common sealed enclosure. The support member with cavities provides a unified structure that holds multiple cells, and the shared atmosphere region connects all cells, simplifying assembly while maintaining the safety benefits of small cell sizes.
3Stability of the object's composition
If cells are constrained in a rigid enclosure, then structural stability is improved, but cycle life decreases due to mechanical stress
Solution Approach 1:
The enclosure incorporates a flexible diaphragm that can expand and contract in response to pressure changes during battery operation. This flexibility allows the structure to maintain stability while accommodating the expansion and contraction of cells during charge-discharge cycles, thereby extending cycle life by reducing mechanical stress.
Solution Approach 2:
The enclosure design transitions from a rigid static structure to a dynamic system where the diaphragm can move and adjust. This dynamic capability allows the enclosure to adapt to changing internal conditions during battery operation, maintaining structural integrity while reducing stress on the cells.
4Quantity of substance
If more active materials are added to increase capacity, then energy density is improved, but mechanical stress on electrodes increases
Solution Approach 1:
The total quantity of active material is distributed across multiple small cells rather than concentrated in a single large cell. Each small cell contains a manageable amount of active material that causes minimal expansion stress, while the cumulative capacity of all cells achieves the desired high energy density.
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 design enhances safety and reduces production costs by distributing mechanical loads and managing thermal runaway effectively, allowing for larger size batteries with tailored power-to-energy ratios and improved assembly efficiency.
Implementation Method 1
The support member includes a kinetic energy absorbing material
Implementation Method 2
The support member includes a kinetic energy absorbing material and the cavity liners are formed of a plastic material
Implementation Method 3
The electrolyte includes at least one of a flame retardant, a gas generating agent, and a redox shuttle
Data Source
AI summary
A multi-core lithium ion battery includes a sealed enclosure and a support member disposed within the sealed enclosure. The sealed enclosure may further include at least two support members housed within individual compartments, separated by shared wall(s). The support member(s) includes a plurality of cavities and a plurality of lithium ion core members which are disposed within the plurality of cavities. The battery may further include a plurality of cavity liners, each of which is positioned between a corresponding one of the lithium ion core members and a surface of a corresponding one of the cavities. The hermetically sealed enclosure may be formed using a clamshell configuration. Structures may be included in proximity to or in contact with the lithium ion core members to control gas/fluid flow therefrom.