Battery Pack Dual-Case Venting for High-Temperature Exhaust Gas
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Solution Overview
Problem
Battery packs with lithium ion batteries face safety issues due to high-temperature exhaust gases ejected from exhaust valves, which can ignite and cause adverse effects when discharged externally, as existing designs fail to safely manage and disperse these gases effectively.
Innovation Solution
A battery pack design featuring a dual-case structure with inner and outer smoke vent holes connected via an expansion gap, where the exhaust gas is dispersed and adiabatically expanded within the inner case before being redirected and discharged through outer smoke vent holes, reducing energy and preventing external ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a smoke vent hole is provided in the exterior case for discharging exhaust gas, then the exhaust gas can be discharged to outside, but the high-temperature exhaust gas thermally melts the exterior case and causes safety issues due to ignition and smoking
Solution Approach 1:
The single smoke vent hole is divided into multiple smoke vent holes (first smoke vent holes and second smoke vent holes) distributed across different surfaces of the exterior case. This segmentation disperses the high-temperature exhaust gas flow across multiple smaller openings rather than one large opening, reducing the thermal load on any single location and preventing localized melting and ignition.
Solution Approach 2:
The smoke vent holes are arranged in multiple spatial dimensions and orientations across different surfaces of the exterior case. By distributing exhaust discharge across multiple dimensions rather than a single location, the thermal energy is dispersed over a larger spatial volume, reducing peak temperatures at any given point and preventing thermal melting and ignition hazards.
2Reliability
If the exhaust valve opens to release internal pressure, then safety against rupture is ensured, but high-temperature exhaust gas is forcefully ejected causing adverse effects
Solution Approach 1:
The single exhaust outlet is segmented into multiple smoke vent holes distributed across different surfaces. This divides the high-temperature gas ejection into multiple smaller streams, reducing the kinetic energy and thermal intensity of each individual jet, thereby minimizing ignition risks and adverse effects while maintaining effective pressure release.
Solution Approach 2:
The harmful high-temperature exhaust gas is redirected through multiple smoke vent holes to discharge away from the battery pack body. By strategically positioning these holes on different surfaces, the harmful thermal and kinetic energy of the exhaust is converted into a controlled discharge pattern that protects the battery pack while still achieving pressure relief.
3Device complexity
If a single smoke vent hole is used for exhaust discharge, then the structure is simple, but the exhaust gas cannot be safely discharged due to thermal melting and ignition risks
Solution Approach 1:
The smoke vent structure is segmented into multiple holes rather than one large hole. This segmentation maintains relative structural simplicity while dramatically improving safety by dispersing thermal loads and preventing localized melting and ignition, thus achieving both simplicity and reliability.
Solution Approach 2:
Different regions of the exterior case are assigned different functional qualities through strategically placed smoke vent holes on various surfaces. This local quality distribution ensures that exhaust discharge occurs in multiple directions away from critical areas, enhancing safety without requiring complex overall structural changes.
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 safely disperses and reduces the energy of high-temperature exhaust gases, preventing ignition and ensuring safer discharge, thereby enhancing the safety of the battery pack.
Implementation Method 1
an expansion gap of the exhaust gas is provided between inner case 20 and outer case 30, the plurality of inner smoke vent holes 27 and the plurality of outer smoke vent holes 37 are connected via expansion gap 8
Data Source
AI summary
A battery pack includes battery cell including the exhaust valve that opens when an internal pressure exceeds a set pressure and case housing battery cell. Case includes inner case housing battery cell and outer case incorporating inner case, inner case includes a plurality of inner smoke vent holes through which the exhaust gas ejected from the exhaust valve passes, and outer case includes a plurality of outer smoke vent holes through which the exhaust gas including passed through inner smoke vent holes passes. In a state where inner case is disposed in outer case, inner smoke vent holes and outer smoke vent holes are disposed at positions not facing each other, and inner smoke vent holes and outer smoke vent holes are opened at positions allowing the exhaust gas to pass in different directions.