Battery Pack Venting and Filtration for Thermal Runaway Containment
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Solution Overview
Problem
Existing battery packs, particularly those using lithium batteries, face challenges in preventing damage from spontaneous thermal runaway events, which can lead to overheating and explosion, causing harm to the device and surrounding peripherals, such as aircraft, due to the lack of effective containment and dissipation of combustion gases and shrapnel.
Innovation Solution
A battery pack design featuring a housing with a multilayer filter and vent system that directs combustion gases through a filter before external venting, maintaining spacing between cells to prevent thermal runaway propagation, and using internal walls as heat sinks to absorb thermal energy and contain the event, along with electrical circuitry alignment to manage eruptions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery packs use lithium batteries for high energy density, then power output is improved, but risk of thermal runaway and explosion increases
Solution Approach 1:
The battery pack is divided into separate compartments with individual cells positioned in specific orientations. Each cell is isolated within the housing structure, preventing direct contact between cells. This segmentation limits the propagation of thermal runaway events to individual cells rather than affecting the entire battery pack.
Solution Approach 2:
A filter is introduced as an intermediary component between the battery cells and the external environment. The filter captures and retains combustion gases and debris generated during thermal runaway, preventing them from reaching surrounding components. This intermediary structure allows the battery to maintain high energy density while providing a safety mechanism to contain harmful effects.
2Volume of moving object
If battery cells are positioned close together for compact design, then device size is reduced, but thermal runaway propagation between cells increases
Solution Approach 1:
The housing structure incorporates localized heat dissipation features and spacing variations between cells. Specific regions of the housing provide enhanced thermal management for individual cells, allowing compact overall design while maintaining adequate thermal isolation between adjacent cells to prevent runaway propagation.
3Stress or pressure
If combustion gases are vented directly to the environment, then pressure buildup is relieved, but flames and shrapnel can escape causing damage
Solution Approach 1:
A filter is introduced as an intermediary component between the battery cells and the external environment. The filter captures and retains combustion gases and debris generated during thermal runaway, preventing them from reaching surrounding components. This intermediary structure allows the battery to maintain high energy density while providing a safety mechanism to contain harmful effects.
Solution Approach 2:
The filter system converts the harmful combustion gases and debris into a contained form that can be safely vented. By capturing and retaining these materials, the system transforms a potentially dangerous direct venting process into a controlled release that protects surrounding components while still relieving pressure.
4Object-affected harmful factors
If battery housing is sealed for protection, then environmental resistance is improved, but combustion gas pressure buildup during malfunction increases
Solution Approach 1:
The housing is designed with pre-planned pressure relief pathways in the form of filters and vents. These features are built into the sealed structure in advance, allowing the housing to maintain its protective sealing while providing controlled routes for combustion gases to escape during thermal runaway events, preventing dangerous pressure buildup.
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 contains and dissipates thermal energy, preventing catastrophic failures by filtering combustion gases, reducing pressure buildup, and isolating cells to minimize the spread of thermal runaway events, thereby ensuring safer operation and compliance with standards like RTCA DO-227A.
Implementation Method 1
the multilayer filter is configured to absorb thermal energy from combustion gases passing therethrough, and may even act as a flame suppressor or arrestor by reducing temperature of the combustion gases below their ignition temperature
Implementation Method 2
the filter may help prevent flames and shrapnel from exiting the battery pack in a thermal runaway event leading to catastrophic failure
Implementation Method 3
The at least one vent may be orientated to direct combustion gases away from first part
Data Source
AI summary
A battery pack for powering an electrical device, comprising: a housing for a plurality of electrochemical cells, each having an elongate body with terminals at either end thereof; and electrical circuitry for coupling in series or parallel the plurality of electrochemical cells in the housing to electrical contacts of the electrical device; wherein the housing comprises: a first part having a body defining a chamber with an opening, the body being configured to retain the plurality of electrochemical cells side by side in the chamber, with one terminal of each cell facing towards the opening; and a second part comprising a filter and at least one vent, with the second part being configured to cover the opening of the chamber when coupled to the first part such that any combustion gases generated in the chamber by electrochemical cell malfunction pass through the opening and the filter before being vented externally of the housing through the at least one vent.