United States Patent and Trademark Office >>
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United States Patent and Trademark Office >>
As the world transitions to clean energy and all-electric mobility, rapid and efficient charging of the lithium-ion battery is becoming increasingly important to the smooth rollout of technologies that rely on electrical energy storage. As a result, manufacturers are developing new innovative approaches to optimize the charging processes and manage the battery cells to maximize their output and efficiency.
StoreDot’s patents describe innovations that increase the charging efficiency of the charger by implementing voltage amplitude modulation or charging multiple cells directly from an AC source, by adjusting, momentarily, the number of charged cells to the instantaneous voltage level of the AC source.
United States Patent and Trademark Office: Direct charging of battery cell stacks >>
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United States Patent and Trademark Office: Chargers with voltage amplitude modulation >>
These two related inventions define a novel approach to charging a battery pack, using an alternating current (AC) source, whilst also describing a method of increasing the charging efficiency of the charger, by modulating the charging voltage amplitude using feedback from at least one cell or energy storage device.
Thus, the first patent describes a method for charging an arrangement of battery cells in a battery pack using an alternating current (AC) source. Charging takes place by supplying a voltage at an AC cycle while adjusting the cell groups being charged according to voltage and/or current levels. The adjustment takes place instantaneously with the cells continuously rearranged to equalize at least one cell parameter among the cells selected from a state of charge (SoC) or a state of health (SoH) and related parameters.
The battery referred to in the patent consists of groups of cells with several parallel-connected branches, each branch having serially connected cells. The groups in the charged assembly each comprise at least one cell, and each cell group is switchable within and/or between the branches.
Whereas this patent describes the process of arranging and re-arranging the charged assembly of cells in various configurations to optimize the charging scheme, the second, related invention, outlines a method of increasing the charging efficiency of a charger by modulating the charging voltage amplitude instead of voltage frequency modulation.
This is achieved by modulating the charging voltage amplitude from a DC-rectified AC power source using feedback from at least one cell or energy storage device that is being charged by the charger while maintaining a charging voltage frequency constant at an LLC resonance frequency of the charger.
By implementing the inventions described in these patents battery-charging equipment manufacturers can expect to improve not only the charger’s performance and efficiency but also the overall performance, safety, and longevity of the battery pack. This is especially important in case of high power battery charging equipment essential for extreme fast charging.
