Hybrid Energy Storage Layout for Fast-Charging Electric Machines
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Solution Overview
Problem
Conventional electric machines, such as battery electric vehicles and autonomous guided vehicles, face inefficiencies due to long charging times, which result in significant non-productive time, increased operational costs, and the need for over-dimensioned batteries, leading to bulky designs and premature aging, with no backup energy source in case of depletion.
Innovation Solution
A hybrid energy storage system comprising a high-power first energy storage device and a lower-power second energy storage device, where the first device can be quickly charged and directly powers the main energy-consuming unit, while the second device powers auxiliary systems and provides backup power when the first device is depleted, eliminating the need for complex converters and allowing charging during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional batteries (lead acid or lithium ion) are used as the sole energy storage device, then the electric machine can operate autonomously for extended periods, but the charging time becomes excessively long (hours), resulting in significant non-productive time and reduced productivity
Solution Approach 1:
The energy storage system is segmented into two distinct devices: a first energy storage device (high power, fast charging capability) and a second energy storage device (lower power, longer duration). This segmentation allows each device to specialize in different functions, resolving the contradiction between fast charging and long autonomy by distributing these requirements across separate components.
Solution Approach 2:
The first energy storage device is designed to provide excessive power capacity for fast charging and high-power consumption periods, while the second device provides partial power for extended autonomy. This partial/excessive action approach allows the system to charge quickly when needed without requiring the entire energy storage capacity to be optimized for fast charging, thus maintaining both fast charging capability and extended autonomy.
2Loss of time
If the battery is over-dimensioned to reduce charging frequency, then the autonomy duration increases, but the device becomes bulky, heavier, and more expensive
Solution Approach 1:
The energy storage system is divided into two specialized devices with different power and energy ratings. The first device handles high-power, short-duration demands enabling fast charging, while the second device handles lower-power, long-duration demands for extended autonomy. This segmentation eliminates the need for a single oversized battery, reducing overall weight and volume while achieving the same operational goals.
Solution Approach 2:
The system changes the power and energy parameters of the energy storage devices from a single uniform specification to two distinct specifications. The first device has high power but moderate energy capacity, while the second device has lower power but higher energy capacity. This parameter differentiation allows optimization of each device for its specific function, reducing total system mass and volume compared to an over-dimensioned single battery approach.
3Device complexity
If a single energy storage device is used, then the system design is simpler, but there is no backup energy source available when the battery is depleted
Solution Approach 1:
Both energy storage devices are designed to be capable of powering the energy consuming unit, providing multi-functionality. The first device can operate independently during fast charging cycles, while the second device can operate independently during extended autonomous operation or serve as backup when the first device is depleted. This universal capability of both devices ensures reliability without requiring complex switching mechanisms.
4Loss of time
If fast charging is implemented using conventional batteries, then the charging time is reduced, but the battery degrades rapidly due to excessive cycling (around 20 times/day)
Solution Approach 1:
The system segments the charging function from the energy storage function. The first energy storage device is optimized for fast charging with high power acceptance capability, while the second device provides stable, long-duration energy storage. This segmentation allows the first device to handle the stress of frequent fast charging cycles without compromising the overall system reliability, as the second device provides a buffer and can be cycled less frequently.
Solution Approach 2:
The two energy storage devices act as intermediaries between the charger and the energy consuming unit. The first device serves as a fast-charging buffer that can rapidly accept and deliver power, while the second device provides stable, long-term energy management. This intermediary arrangement protects the battery system from the detrimental effects of excessive fast charging cycles while maintaining fast charging capability.
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 approach significantly reduces charging time, decreases non-productive time, and enhances operational efficiency by minimizing the number of vehicles and chargers needed, while ensuring reliable backup power without additional space or cost, thus improving productivity and flexibility.
Implementation Method 1
a first energy storage device and a second energy storage device, the first energy storage device having a higher power with respect to the second energy storage device
Implementation Method 2
the second energy storage device is configured to power the second energy consuming unit
Data Source
AI summary
An electric machine including a first energy consuming unit and a second energy consuming unit, the first energy consuming unit requiring a higher power energy source and the second energy consuming unit requiring a lower power energy source, wherein the machine further includes a first energy storage device and a second energy storage device, the first energy storage device having a higher power with respect to the second energy storage device, wherein the first energy storage device is configured to power the first energy consuming unit, wherein the second energy storage device is configured to power the second energy consuming unit, and wherein the first energy storage device is connectable to a charger for charging, the first energy storage device requiring a lower charging time for reaching its maximum state of charge than the second energy storage device, and wherein the first energy storage device is configured to directly provide power to the first energy consuming unit.