Energy Storage Device Series-Parallel Switching for Low Voltage Charging
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Solution Overview
Problem
Existing energy management circuits for autonomous microsystems face inefficiencies when handling diverse energy sources with varying electrical specifications, requiring either dedicated circuits for specific sources or configurable circuits that often rely on external control systems, leading to reduced overall efficiency.
Innovation Solution
An energy storage device with a charge and discharge management circuit that alternately connects energy storage units in parallel or series mode, using comparators and switches to manage charging and discharging based on threshold voltages, allowing direct charging from low voltage sources and efficient energy transfer without an external load manager.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a configurable management circuit is used to handle multiple energy sources, then versatility is improved, but device complexity increases due to the need for external control systems
Solution Approach 1:
The management circuit uses the energy stored in the microbattery itself to power the control logic and switching operations. The microbattery voltage directly controls the gate of the transmission gate, enabling automatic switching between charging and discharging modes without external control voltage requirements
Solution Approach 2:
A single management circuit design can handle multiple energy sources with different voltage characteristics by configuring the transmission gate and switching networks appropriately, eliminating the need for separate dedicated circuits for each energy source type
2Adaptability or versatility
If an external control system is used to manage energy transfer, then adaptability is improved, but energy efficiency deteriorates due to additional power consumption
Solution Approach 1:
The control logic is powered directly from the microbattery voltage rather than requiring an external control voltage source. This eliminates the need for additional power supply circuits and reduces overall system power consumption while maintaining full energy management functionality
3Loss of energy
If dedicated management circuits are used for specific energy sources, then energy efficiency is improved, but adaptability deteriorates
Solution Approach 1:
The management circuit incorporates configurable switching networks and transmission gates that can be adjusted to accommodate different energy source characteristics. The same basic circuit architecture can efficiently manage photovoltaic, piezoelectric, or other energy sources by reconfiguring the switching elements
4Quantity of substance
If microbatteries are charged at high voltage, then energy density is improved, but charging compatibility deteriorates with low voltage sources
Solution Approach 1:
The circuit dynamically reconfigures the microbattery connections between series and parallel configurations based on the charging source voltage. When charged from low voltage sources, multiple microbatteries are connected in parallel to accept the lower voltage; when delivering power, they can be connected in series to provide higher voltage output
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 solution enables efficient energy storage and delivery from low voltage sources to higher voltage levels, optimizing energy transfer and autonomy in applications like radiofrequency, thermal, and photovoltaic energy harvesting, while eliminating the need for external control systems, thus enhancing overall system efficiency.
Implementation Method 1
energy storage units with n ≥ 2; a charge and discharge management circuit electrically connected to the n storage units
Implementation Method 2
of the first means to trigger the switch from parallel mode to series mode, by exceeding a first threshold voltage (V threshold1) at the level of one of the energy storage units
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
The subject of the invention is an energy storage device comprising at least one block, said block being connected to an input voltage Vin and delivering a voltage Vout that is higher than Vin and including: - n energy storage units, where n ≥ 2; - a charge and discharge management circuit that is electrically linked to the n storage units and making it possible to alternately connect all of the energy storage units of one and the same block to one another, in parallel or in series; - the energy storage units respectively having an end-of-charge voltage Vfin de charge and an end-of-discharge voltage Vfin de décharge; - said block having a block voltage VBloc defined between the low potential of the first energy storage unit and the high potential of the nth energy storage unit, wherein said charge and discharge management circuit includes: - first means for triggering the switch from parallel mode to series mode, by a first voltage threshold (Vseuil1) being exceeded at one of the energy storage units, said first threshold voltage corresponding to a target end-of-charge voltage of said storage unit; - second means for triggering the switch from series mode to parallel mode by the voltage VBloc falling below a second threshold voltage (Vseuil2), said second threshold voltage corresponding to a voltage that is equal to the sum of the n end-of-discharge voltages of the n energy storage units; - said first means and said second means comprising a comparator block.