Battery Pack Thermal Runaway Mitigation via Weakened Portion and Spray Pipeline
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Solution Overview
Problem
High energy density battery packs in electric vehicles face serious thermal safety issues due to the risk of thermal runaway, which can lead to unsafe conditions for both the vehicle and its passengers, posing a barrier to the widespread adoption of electric automobiles.
Innovation Solution
A battery pack design incorporating secondary batteries with weakened portions and a spray pipeline system, where the spray pipeline is strategically positioned relative to the weakened portions to allow heat flow to break through and discharge, forming an opening to spray a medium that effectively mitigates thermal runaway by reducing high temperatures and preventing heat spread to other batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the energy density of the battery pack is increased by using a larger number of secondary batteries, then the endurance mileage is improved, but the thermal safety becomes more serious
Solution Approach 1:
The battery pack is divided into multiple independent battery modules, each equipped with its own weakened portion and spray pipeline. This segmentation isolates thermal runaway events to specific modules, preventing spread to the entire battery pack while maintaining high energy density through increased battery quantity.
Solution Approach 2:
A spray medium (fire suppression agent) is introduced as an intermediary substance between the thermal runaway source and surrounding batteries. The spray pipeline delivers this medium to the weakened portion area, where it acts as a barrier to heat transfer and chemical reaction propagation, thereby improving thermal safety without reducing energy density.
2Speed
If the spray pipeline is positioned closer to the weakened portions for faster response, then the thermal runaway control is improved, but the risk of damage from thermal runaway increases
Solution Approach 1:
The spray pipeline is pre-positioned at an optimized spacing B from the weakened portions, and the spray medium is pre-loaded in the storage case. When thermal runaway occurs, the system immediately activates the spray without delay for positioning or preparation, achieving fast response while maintaining safe distance through the pre-calculated spacing relationship.
Solution Approach 2:
The spacing B between the spray pipeline and weakened portions is dynamically optimized based on battery capacity A using the formula 15≤3×[(A+25)/B]0.5. This parameter adjustment ensures the spray pipeline is close enough for rapid response but far enough to avoid direct thermal damage, with the optimal distance scaling according to battery size.
3Reliability
If additional monitoring and control devices are added to improve safety, then the thermal runaway detection is improved, but the device complexity increases
Solution Approach 1:
The battery pack system uses the thermal runaway event itself (heat flow and pressure changes) to automatically trigger the spray response through the weakened portion mechanism. This self-activating system eliminates the need for separate sensors, control units, and power supplies, achieving reliable thermal runaway detection and response without adding device complexity.
Solution Approach 2:
The harmful thermal runaway event is converted into a useful triggering mechanism. The heat flow and pressure changes that indicate thermal runaway also serve as the activation force for the spray system through the weakened portion design, transforming a dangerous phenomenon into a beneficial automatic alarm and response trigger without requiring additional monitoring devices.
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 controls thermal runaway, enhancing safety performance by ensuring quick and accurate response to thermal events, potentially reducing the need for additional monitoring and control devices, and maintaining a compact, lightweight design with high energy density.
Implementation Method 1
a heat flow resulting from thermal runaway of the secondary battery is able to break through the weakened portion to be discharged
Implementation Method 2
a spray medium in the spray pipeline being sprayed to an abnormal secondary battery in thermal runaway via the opening
Data Source
Figure 1~2
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Figure 5~6
AI summary
The application discloses a battery pack, vehicle and control method for alleviating thermal runaway spreading of a battery pack. The battery pack includes a plurality of secondary batteries and a spray pipeline. A housing of the secondary battery includes a weakened portion, so that a heat flow resulting from thermal runaway of the secondary battery is able to break through the weakened portion to be discharged. The spray pipeline is corresponding to weakened portions of the secondary batteries and is arranged at a spacing B from the weakened portions of the secondary batteries. At least a portion of the spray pipeline corresponding to the weakened portions is a breakthrough region which is able to form an opening under an action of the heat flow. The spray medium in the spray pipeline is sprayed to a secondary battery in thermal runaway via the opening. A capacity A of the secondary battery by Ah and a spacing B between the weakened portion and the spray pipeline by mm satisfy: 10 ≤ 3×[(A+25)/B]0.5 ≤ 35 . The battery pack, vehicle and control method for alleviating thermal runaway spreading of the battery pack disclosed by the application can alleviate thermal runaway spreading in the battery pack, thereby improving the safety performance of the battery pack and the vehicle.