Emergency Cooling Device for High-Density Energy Storage Cells
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Solution Overview
Problem
High-voltage energy storage systems with increasing energy density face challenges in thermal stability, where a cell-internal short circuit can lead to heat propagation to adjacent cells, potentially causing a thermal event, necessitating additional safety measures to prevent or slow down this propagation.
Innovation Solution
The implementation of an energy storage system with cooling plates between cells and emergency switching devices that allow coolant inflow only when a cell exceeds a defined temperature threshold, using fusible alloys to control coolant flow and minimize weight, along with a heating device to assist melting for faster cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If energy density of energy storage cells is increased to 200 Wh/kg and higher, then energy storage capacity is improved, but thermal stability deteriorates and heat propagation to adjacent cells becomes sufficient to cause thermal events
Solution Approach 1:
The energy storage system is divided into modular units with individual cooling plates for each cell or group of cells. Each cooling plate acts as an independent barrier that can contain thermal events locally, preventing heat propagation to adjacent cells while maintaining high energy density in each module.
Solution Approach 2:
Cooling plates are introduced as intermediary components between energy storage cells. These plates serve as thermal barriers that intercept heat propagation pathways, using coolant circulation to absorb and remove excess heat before it can reach neighboring cells, thus maintaining system reliability at high energy densities.
2Reliability
If cooling plates are arranged between all energy storage cells, then thermal event propagation is prevented, but system complexity and coolant quantity requirements increase
Solution Approach 1:
Cooling plates are strategically positioned only between cells or cell groups that pose the highest thermal risk, rather than uniformly between all cells. This localized approach maintains effective thermal event containment while reducing the total number of cooling plates and coolant requirements, thereby lowering system complexity.
Solution Approach 2:
The cooling system is designed to provide more than sufficient cooling capacity at critical locations where thermal events are most likely to propagate. By concentrating cooling resources at these partial locations rather than distributing them uniformly, the system achieves effective thermal management with reduced overall complexity and coolant quantity.
3Ease of operation
If emergency switching devices are provided for each cell and cooling plate, then localized cooling control is achieved, but device complexity and weight increase
Solution Approach 1:
Multiple emergency switching devices are merged into single centralized control units that can manage cooling for multiple cells and cooling plates simultaneously. This consolidation maintains the capability for localized cooling control through electronic actuation while significantly reducing the total weight and complexity compared to having separate mechanical switches at each location.
Solution Approach 2:
Traditional mechanical emergency switching devices are replaced with electronic or electromechanical actuators that can be controlled remotely and simultaneously. This substitution reduces the weight and complexity of the switching mechanism while maintaining the ability to quickly activate localized cooling control when thermal events are detected in specific cells.
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 solution effectively prevents or slows the jump of thermal events from affected cells to adjacent cells, ensuring safety by localized cooling with minimal coolant usage and weight, while integrating with existing cooling systems for efficiency.
Implementation Method 1
emergency switching devices each of which is assigned to one energy storage cell and to one or two cooling plates. The emergency switching devices permit an inflow of the coolant or refrigerant into the associated cooling plates only if a temperature of the respectively associated energy storage cell overshoots a defined threshold temperature
Implementation Method 2
along with a heating device to assist melting for faster cooling
Implementation Method 3
cooling plates which are arranged between the energy storage cells and into which coolant or refrigerant can be introduced
Data Source
AI summary
An energy store has a plurality of electrical energy storage cells, which are connected electrically in series or parallel and are combined to form an energy storage module. Cooling plates are arranged between the energy storage cells and into which coolant or refrigerant can be introduced. A plurality of emergency switching devices are provided, each of which is associated with an energy storage cell and one or two cooling plates. The emergency switching devices allow the coolant or refrigerant to flow into the associated cooling plates only if a temperature of the associated energy storage cell exceeds a defined limit temperature.