PCM-Lined Battery Cooling Channels to Contain Thermal Runaway
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Solution Overview
Problem
Existing battery systems fail to effectively manage thermal runaway, leading to potential explosions and fires due to convective heat propagation from overheated cells, which can trigger thermal runaway in adjacent cells.
Innovation Solution
A cooling circuit with phase-change material (PCM) lined cooling channels that melt and block heat transfer during thermal runaway, redirecting the cooling fluid to prevent further cell heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling channels continuously cool battery cells, then cooling efficiency is improved, but thermal runaway propagation through cooling fluid occurs
Solution Approach 1:
The cooling channel is lined with phase change material that undergoes phase transition from solid to liquid at a specific melting point temperature. When the battery cell temperature reaches the melting point, the PCM melts and blocks the cooling channel, preventing hot cooling fluid from reaching adjacent battery cells and propagating thermal runaway convectively.
Solution Approach 2:
The phase change material acts as an intermediary substance between the battery cell and the cooling fluid. It absorbs excess heat through phase transition and physically blocks the cooling channel, preventing direct thermal coupling between overheated cells via the cooling fluid.
2Productivity
If cooling fluid flows through all cooling channels, then heat dissipation is improved, but adjacent cells are heated by hot cooling fluid during thermal runaway
Solution Approach 1:
The PCM lined in the cooling channel undergoes phase transition when exposed to thermal runaway temperatures, melting and blocking the channel to prevent hot cooling fluid from flowing to adjacent cells, thereby eliminating the harmful thermal propagation while maintaining normal heat dissipation functionality.
Solution Approach 2:
The phase change material automatically activates during thermal runaway events by melting and blocking the cooling channel based on temperature conditions, providing self-protection functionality without requiring external control systems or additional energy input.
3Object-affected harmful factors
If phase-change material blocks cooling channel during thermal runaway, then convective heat propagation is prevented, but cooling channel is blocked
Solution Approach 1:
The PCM blocks the cooling channel through phase transition from solid to liquid when temperature reaches the melting point. The blocked channel prevents hot cooling fluid from propagating thermal runaway to adjacent cells. The system accepts this temporary blockage as a necessary safety measure during thermal runaway events.
Solution Approach 2:
The cooling channel blockage, which appears harmful to normal cooling operation, is actually converted into a beneficial safety feature during thermal runaway. The blocked channel prevents the more harmful convective propagation of thermal runaway to adjacent cells, transforming a potential operational disadvantage into a protective mechanism.
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
Prevents convective heat propagation, containing thermal runaway events and protecting adjacent cells from excessive heating, thereby enhancing safety and reliability.
Implementation Method 1
the cooling channel segments are lined, at an inner wall thereof, with a phase-change material, PCM, which is adapted to melt and detach from the inner wall when the battery cell to which the cooling channel segment is thermally conductively connected to overheats
Implementation Method 2
the cooling channel segments each comprising an upstream end where the cooling fluid enters into the cooling channel segment and a downstream end where the cooling fluid leaves the cooling channel segment
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
Battery system (100), comprising: a plurality of battery cells (12) arranged to form one or more battery packs (14), a cooling circuit (20) including cooling channels (22) for cooling the battery cells (12) via cooling fluid flowing along the cooling channels (22) in a flow direction (F), wherein the cooling channels (22) include cooling channel segments (24), each of the cooling channel segments (24) extending alongside and being thermally conductively connected to one of the battery cells (12), the cooling channel segments (24) each comprising an upstream end (26) where the cooling fluid enters into the cooling channel segment (24) and a downstream end (27) where the cooling fluid leaves the cooling channel segment (24), wherein the cooling channel segments (24) are lined, at an inner wall (28, 29) thereof, with a phase-change material, PCM, (30) which is adapted to melt and detach from the inner wall (28, 29) when the battery cell (12) to which the cooling channel segment (24) is thermally conductively connected to overheats, the PCM (30) being further adapted to be carried along the flow direction (F) by the cooling fluid and to solidify and accumulate at the downstream end (27) of the cooling channel segment (24) thereby blocking the cooling fluid from leaving the cooling channel segment (24).