Heating Circuit for Battery Electrolyte Warming at Very Low Temperatures
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Solution Overview
Problem
Current energy storage devices such as supercapacitors and lithium ion batteries face significant challenges in charging and discharging at very low temperatures, with electrolytes becoming solid, hindering ion transportation and causing irreversible damage due to lithium plating, which limits their performance in applications like munitions and vehicles.
Innovation Solution
A method involving high frequency current application to short the internal surface capacitance of energy storage devices, generating heat to raise electrolyte temperature and enable rapid charging and discharging, using a controller to manage switching between input voltage and grounding inputs to maintain symmetric current flow without a DC component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high rate charging is attempted at very low temperatures, then charging speed is improved, but the electrolyte becomes solid and ion transportation is hindered
Solution Approach 1:
The heating circuit is activated before charging to pre-heat the electrolyte to a temperature where it remains liquid and conductive. This preliminary thermal preparation ensures that when charging begins, the electrolyte is already in a state suitable for ion transportation, preventing the contradiction between fast charging and maintained ion mobility at low temperatures.
2Reliability
If heating is applied to raise electrolyte temperature, then ion mobility is improved, but energy loss increases
Solution Approach 1:
The heating circuit uses the battery's own internal resistance to generate heat through controlled current flow, rather than requiring an external heating source. This self-heating mechanism reduces energy loss by utilizing the battery's inherent properties and allows for precise temperature control during the heating process, minimizing unnecessary energy consumption while ensuring adequate ion mobility.
3Reliability
If charging is delayed to allow temperature increase, then charging efficiency is improved, but charging time increases
Solution Approach 1:
The heating and charging processes are overlapped and executed simultaneously rather than sequentially. The heating circuit operates during the charging process to maintain optimal electrolyte temperature, ensuring continuous efficient charging without interruption or delay. This eliminates the time loss associated with separate heating and charging stages while maintaining high charging efficiency throughout the entire charging duration.
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
Enables rapid charging and discharging of energy storage devices at temperatures as low as -65 to -45°F, maintaining peak performance by preventing damage and ensuring efficient ion mobility.
Implementation Method 1
A heating circuit is provided for heating a core of a battery or energy storage device
Implementation Method 2
switching between an input voltage and a grounding input provided to one of the inputs at a frequency sufficient to effectively short the internal surface capacitance of the energy storage device to generate heat
Data Source
AI summary
A heating circuit for an energy storage device having a core with an electrolyte, inputs, a capacitance across the electrolyte and the core, and internal surface capacitance between inputs which can store electric field energy between internal electrodes of the energy storage device that are coupled to the inputs, including: a power supply coupled to an input, the power supply provides positive and negative input currents to one input, the positive input current flows in to the input and the negative input current flows out of another input; and a controller that switches between the positive and negative input currents to provide the positive input current and the negative input current to the one of the inputs at a frequency sufficient to effectively short the internal surface capacitance of the energy storage device to generate heat and raise a temperature of the electrolyte.