Traction Battery Pressure Equalization Valve for Thermal Venting
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Solution Overview
Problem
High voltage traction battery packs in electrified vehicles face pressure differentials due to temperature fluctuations, leading to potential unintended release of battery vent byproducts during thermal events, which existing technologies fail to adequately prevent.
Innovation Solution
Incorporating a pressure equalization device within the outer enclosure assembly, featuring a housing with a valve that moves between open and closed positions in response to thermal events, utilizing a water-impermeable membrane and various actuation mechanisms such as springs, thermostatic actuators, or intumescent coatings to manage gas paths and prevent vent byproduct escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer enclosure assembly is sealed to prevent moisture accumulation, then moisture protection is improved, but pressure differentials during temperature fluctuations cause unintended release of battery vent byproducts
Solution Approach 1:
The valve changes its state based on temperature parameters. During thermal events, the temperature parameter triggers the valve to transition from open to closed position, preventing harmful byproduct release while maintaining the sealed enclosure's moisture protection capability
Solution Approach 2:
The valve is designed to be dynamic rather than static, automatically transitioning between open and closed positions in response to thermal events. This dynamic behavior allows the system to maintain moisture protection while adaptively preventing harmful emissions during temperature fluctuations
2Object-generated harmful factors
If a valve is added to control gas paths during thermal events, then prevention of vent byproduct escape is improved, but device complexity increases
Solution Approach 1:
The valve mechanism is designed to operate autonomously using passive actuation methods such as thermal expansion, magnetic fields, or pressure differentials. The valve self-regulates the gas path based on thermal event conditions without requiring external control systems, thereby preventing harmful emissions while minimizing added complexity
Solution Approach 2:
The patent replaces complex mechanical valve actuation systems with alternative mechanisms such as thermal actuators, magnetic actuators, or material property changes (e.g., shape memory alloys). This substitution achieves the same harmful emissions prevention function with reduced mechanical complexity
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
Effectively equalizes pressure within the battery pack during normal operations while preventing the unintended release of battery vent byproducts during thermal events, ensuring safer and more controlled venting strategies.
Implementation Method 1
the valve is separated from the sealing surface by a thermostatic actuator when in the first position
Implementation Method 2
the valve includes an intumescent coating that is configured to expand to close the gas path
Implementation Method 3
the valve is biased apart from the sealing surface by a spring when in the first position
Implementation Method 4
the pressure equalization device includes a water-impermeable membrane held within the housing
Data Source
AI summary
Traction battery pack designs are disclosed for use in electrified vehicles. Exemplary traction battery packs may include an outer enclosure assembly establishing an interior, and a battery array housed within the interior. A pressure equalization device may be disposed within a wall of the outer enclosure assembly and may be configured to both equalize the pressure inside the battery pack during normal battery operations and to prevent the unintended release of battery vent byproducts during battery thermal events.