Resonant Self-Heating Battery Circuit for Cold-Start Prewarming
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Solution Overview
Problem
Batteries and devices powered by them do not perform efficiently at cold temperatures, necessitating a method to warm the battery without adverse effects on device operation.
Innovation Solution
A self-heating battery circuit utilizing a resonant circuit connected across the battery terminals, generating high alternating currents through an energy superposition unit with an inductor and switch, which heats the battery efficiently by dissipating power across internal resistance, and includes a freewheeling circuit for safe operation and reduced power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a battery is warmed to operating temperature, then battery performance is improved, but energy is consumed and device operation may be adversely affected
Solution Approach 1:
The battery warms itself by utilizing its own internal resistance and the power management circuit's existing components. The heating current flows through the battery's internal resistance, generating heat without requiring an external heating element or additional energy source beyond what the power management circuit already provides.
Solution Approach 2:
The patent converts the typically harmful effect of internal resistance (power loss and heat generation during normal operation) into a beneficial heating mechanism. By deliberately applying a heating current through the internal resistance, the previously wasted energy becomes a useful heating source that warms the battery to optimal operating temperature.
2Productivity
If a resonant circuit is used to generate high alternating currents for heating, then heating efficiency is improved, but device complexity increases
Solution Approach 1:
The power management circuit components (inductor, capacitor, switch) are designed to serve dual functions: normal power management operations and battery heating operations. The same inductor and capacitor that function in the regular power conversion circuit also form the resonant circuit for heating, eliminating the need for separate dedicated heating components.
Solution Approach 2:
The heating function is merged with the existing power management circuit rather than being implemented as a separate system. The resonant heating circuit shares components with the power management circuit, combining two functions into one integrated system that reduces overall device complexity.
3Temperature
If heating current flows through the battery, then battery is warmed efficiently, but power loss occurs during conduction and switching
Solution Approach 1:
The heating is implemented using periodic alternating current at resonant frequency rather than continuous direct current. The resonant circuit oscillates current through the battery, and the heating effect accumulates over multiple cycles while allowing the circuit to reset and minimize losses during switching transitions.
Solution Approach 2:
The patent changes the parameters of current flow by using alternating current at resonant frequency instead of direct current. This parameter change enables the circuit to operate at peak efficiency points, minimizing resistive losses and optimizing the heating effect while reducing overall power loss.
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 solution achieves high efficiency, improved battery performance, low conduction and switching losses, and independent heating current magnitude, enabling effective pre-warming of batteries for optimal operation without excessive cost or energy waste.
Implementation Method 1
heats the battery efficiently by dissipating power across internal resistance
Implementation Method 2
A self-heating battery circuit utilizing a resonant circuit connected across the battery terminals, generating high alternating currents
Data Source
AI summary
The disclosed exemplary apparatuses, systems and methods may provide a self-heating battery circuit, that comprises: a high voltage battery having terminals, and a parasitic internal resistance (R1) and a parasitic terminal inductance (L1); a resonant circuit connected across the battery terminals suitable to generate high alternating currents about its resonant frequency, fr; an energy superposition unit connected across a capacitance of the resonant circuit, and including a switch (K1), wherein K1 is switched on and off at the resonant frequency, fr, and at a first duty cycle pursuant to a switch control signal, thereby generating a high alternating current through the high voltage battery.