Battery-Capacitor Hybrid ESS for High-Temperature Power Bursts
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Solution Overview
Problem
Conventional battery-only energy storage systems are oversized and unsafe when required to handle high power at elevated temperatures, as they necessitate the use of high-rate lithium cells, which limits their power handling capability per unit weight and volume.
Innovation Solution
A battery-capacitor hybrid energy storage system that combines a battery with a high-temperature electrochemical double-layer capacitor (EDLC) to provide a suitable combination of power handling and energy capacity, reducing the need for high-rate lithium cells and enhancing safety, with the EDLC designed to minimize leakage current at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a battery-only energy storage system uses high-rate lithium cells to meet high power handling requirements, then power handling capability is improved, but system weight and volume increase significantly
Solution Approach 1:
The energy storage system is segmented into two functional components: a battery for energy capacity and an EDLC for power handling. This segmentation allows each component to be optimized for its specific function, with the EDLC handling high-power bursts and the battery providing sustained energy, thereby reducing the overall weight compared to using high-rate lithium cells for the entire system.
Solution Approach 2:
The patent combines a battery and an EDLC into a hybrid energy storage system. The EDLC is electrically connected in parallel with the battery, creating a unified system where the EDLC handles high-power transient demands while the battery provides sustained energy, achieving superior power-to-weight ratio compared to battery-only systems.
2Power
If a battery-only energy storage system is oversized to meet high power requirements, then power handling capability is improved, but energy capacity efficiency deteriorates
Solution Approach 1:
The system segments power delivery functions between the EDLC and battery. The EDLC handles high-power transient demands due to its low ESR and high power density, while the battery maintains steady-state operation. This segmentation allows the battery to be sized for energy capacity rather than being oversized for power requirements, improving energy capacity efficiency.
3Power
If high-rate lithium cells are used to meet high power requirements, then power handling capability is improved, but system safety deteriorates
Solution Approach 1:
The patent merges a battery with an EDLC in a hybrid configuration. The EDLC, being inherently safer with no thermal runaway risk, handles high-power transient demands that would otherwise require high-rate lithium cells. This combination maintains high power handling capability while improving system safety by eliminating the need for high-rate lithium cells.
4Temperature
If an EDLC operates at high temperatures, then high temperature application capability is improved, but leakage current increases
Solution Approach 1:
The patent employs parameter changes in the EDLC design, specifically using a solid polymer electrolyte instead of liquid electrolyte. This material parameter change enables the EDLC to operate at high temperatures (up to 330°C) while maintaining low leakage current (less than 1 amp per liter), as the solid polymer electrolyte exhibits significantly reduced temperature-dependent leakage compared to conventional liquid electrolytes.
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 system effectively handles high power bursts while maintaining energy capacity and reducing weight and volume, with the EDLC exhibiting low leakage current and efficient operation from -20°C to 300°C, ensuring the battery is not excessively drained and achieving lower overall weight and volume compared to high-rate lithium systems.
Implementation Method 1
including a high power electrochemical double layer capacitor (EDLC) for providing intermittent bursts of high power output
Implementation Method 2
a battery having an impedance for providing a substantially constant power output
Data Source
AI summary
A hybrid energy storage system (ESS) includes a first energy storage device including a battery having an impedance for providing a substantially constant power output, and a second energy storage device linked to the first energy storage and including a high power electrochemical double layer capacitor (EDLC) for providing intermittent bursts of high voltage output in a range of 1.5 to 3.0 volts, wherein an operation rating of the second energy source is within a temperature range between 75 degrees Celsius and 330 degrees Celsius while exhibiting a leakage current less than 1 amp per liter of volume over the range of operating temperatures and at a voltage up to a rated voltage.