Crash-Safe Battery Pack With Frangible Module Isolation
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Solution Overview
Problem
Battery packs in electric vehicles, such as electric aerial vehicles, are at risk of thermal runaway during impacts due to short circuits, leading to temperature rises, fires, explosions, and toxic gas emissions.
Innovation Solution
A crash-safe battery pack design featuring a case with a battery storage zone and a crush zone, where a frangible connection between battery modules breaks under predetermined pressure loads, disconnecting the modules to prevent short circuits and reduce the risk of thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery modules are connected in series to increase voltage and power output, then the energy density and performance of the battery pack is improved, but the risk of thermal runaway during impact increases due to potential short circuits
Solution Approach 1:
The battery pack is divided into multiple battery modules that can be electrically connected in series to achieve high power output. Each module is a separate unit that can be independently managed, allowing the system to maintain high voltage and power while reducing the energy contained in each individual module, thereby limiting the potential impact of thermal runaway.
Solution Approach 2:
A frangible connection element is introduced as an intermediary component between battery modules. This element normally provides electrical conduction but is designed to break under impact loads, serving as a mediator that allows normal high-power operation while preventing catastrophic short circuits during impact events.
2Reliability
If a frangible connection element is introduced to break under impact and prevent short circuits, then the safety against thermal runaway is improved, but the device complexity increases
Solution Approach 1:
The frangible connection element is extracted as a separate, dedicated safety component rather than being integrated into the main battery module structure. This allows the safety function to be independently designed and optimized while keeping the rest of the battery system relatively simple and modular.
Solution Approach 2:
The frangible connection element is designed with specific material properties and geometric features that cause it to fail at predetermined impact thresholds. By controlling parameters such as material strength, cross-sectional area, and fracture toughness, the element breaks at specific impact levels while remaining intact during normal operation, providing safety without requiring complex control systems.
3Object-affected harmful factors
If the battery pack is designed with a crush zone to absorb impact energy, then the protection against impact is improved, but the volume occupied by the battery pack increases
Solution Approach 1:
A crush zone is designed into the battery pack structure ahead of the battery modules in the impact direction. This zone is specifically engineered to deform and absorb impact energy before it reaches the battery modules, providing beforehand cushioning that protects the modules without requiring excessive overall pack volume.
Solution Approach 2:
The crush zone is constructed using composite materials or structures that provide high energy absorption per unit volume. These materials allow the crush zone to be compact while still absorbing sufficient impact energy to protect the battery modules, minimizing the volume penalty associated with impact protection.
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 reduces the risk of catastrophic thermal runaway during impacts by disconnecting battery cells, thereby minimizing the potential for short circuits and preventing excessive heating, thus ensuring safer operation of electric aircraft.
Implementation Method 1
a frangible connection located substantially within the crush zone between the first battery module and the second battery modules. The frangible connection configured to provide electrical conduction between the first battery module and the second battery module and break under a predetermined pressure load
Data Source
AI summary
Aspects relate to systems and methods of use for a crash safe battery pack that includes a case, a first battery module located within the case and mounted to the case with at least a breakaway mount, a second battery module located within the case, a frangible connection configured to provide electrical conduction between the first battery module and the second battery module, and a die configured to contact and separate the frangible connection when the crash safe battery pack is impacted with a sufficiently great connection breaking force.