Power-Densifying EV Charging Station Using DC Energy Storage
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Solution Overview
Problem
Existing charging technologies limit the convenience and practicality of direct current fast charging (DCFC) to residential and commercial locations due to the lack of high-power infrastructure, restricting EV owners to slower AC charging options.
Innovation Solution
A power-densifying charging station that accumulates high-voltage DC charge in a DC storage device using a low-power energy source, such as residential grid power, and selectively offloads it to a high-voltage battery pack via a Level 3 DC charge coupler, eliminating the need for a boost converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a low-power AC power supply is used for charging, then the charging station can be deployed at residential locations without specialized infrastructure, but the charging power is limited and cannot deliver DC fast charging
Solution Approach 1:
The system performs preliminary energy accumulation during off-peak hours when the low-power AC supply is available, storing energy in a DC storage device. This preliminary charging action enables the system to deliver high-power DC fast charging later when needed, resolving the contradiction between using accessible low-power infrastructure and delivering high charging power.
Solution Approach 2:
A DC storage device is introduced as an intermediary between the low-power AC power supply and the high-voltage battery pack. This intermediary accumulates energy from the limited AC source and releases it at high power levels, enabling DC fast charging capability at locations with only standard AC infrastructure.
2Power
If a boost converter is used to step up voltage from low-power AC to high-voltage DC, then DC fast charging can be delivered, but the system complexity increases and the invention specifically eliminates this component
Solution Approach 1:
The invention extracts and removes the boost converter from the traditional DC fast charging system architecture. Instead of using active power electronics to step up voltage, the system uses a DC storage device to accumulate voltage and energy passively, then delivers high power through direct connection, eliminating the complex boost converter while maintaining DC fast charging capability.
Solution Approach 2:
The system performs preliminary voltage accumulation in the DC storage device during the charging phase, so that when fast charging is needed, the high voltage is already stored and ready for immediate delivery without requiring real-time voltage conversion through complex power electronics.
3Productivity
If high-power DC fast charging is delivered directly from the power supply, then charging speed is maximized, but specialized high-power infrastructure is required at every location
Solution Approach 1:
The system accumulates high-voltage DC energy in the DC storage device during off-peak hours or when the vehicle is not connected, performing the energy accumulation action in advance. When the vehicle needs fast charging, the pre-accumulated energy is delivered immediately, achieving high charging speed without requiring continuous high-power infrastructure.
Solution Approach 2:
The DC storage device serves as an intermediary that decouples the low-power AC infrastructure from the high-power charging demand. It accumulates energy when available and delivers it at high power when needed, enabling fast charging at locations with standard AC infrastructure while maintaining location flexibility.
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 DCFC at locations with low-power energy sources by storing charge over an extended period and delivering it in a shorter duration, providing high-power charging without the need for specialized infrastructure, thus extending DCFC benefits to a wider range of locations.
Implementation Method 1
a DC storage device operable for accumulating a high-power DC charging voltage from the low-power input voltage during a charge accumulation stage of operation
Implementation Method 2
the LPCM may include an AC-to-DC converter operable for converting the low-power input voltage from an AC waveform to a DC waveform
Implementation Method 3
the DC storage device may include a flywheel arrangement having a low-power AC motor, a flywheel connected to the low-power AC motor, and a high-power DC generator connected to the flywheel
Data Source
AI summary
A power-densifying charging station includes a low-power charging module (LPCM), a direct current (DC) storage device, electrical switches, and a controller. The LPCM receives a low-power input voltage from a low-power energy source. The DC storage device accumulates a high-power DC voltage from the low-power input voltage during a charge accumulation stage of operation. The switches selectively connect the charging station to the energy source, the LPCM to the DC storage device, and the DC storage device to a high-voltage offboard battery pack during a charge delivery stage of operation. The controller is in communication with and operable for controlling the LPCM, the DC storage device, and the switches during the charge accumulation and delivery stages of operation via performance of a corresponding method.