Battery Charging Pulses to Prevent Separator Pore Clogging
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Solution Overview
Problem
Charging of rechargeable batteries, particularly lithium-ion batteries, is hindered by pore clogging in separators due to charge carriers, leading to increased internal resistance and thermal stress, which delays the charging process.
Innovation Solution
The method involves dividing the charging process into intervals with voltage pulses adjusted based on state and material parameters, including negative voltage pulses to reduce the force on separators and prevent blockages, optimizing the charging voltage to minimize internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct current charging is used to charge the battery, then the charging process can proceed continuously, but charge carriers clog the separator pores increasing internal resistance and thermal stress
Solution Approach 1:
The patent applies periodic action by switching between charging and discharging modes in cycles. During charging, charge carriers move through the separator and may clog pores. By periodically reversing to discharging mode, the patent prevents pore clogging and maintains low internal resistance, enabling sustained high charging speeds without the harmful effects of continuous charging.
2Loss of time
If higher charging currents are applied to reduce charging time, then charging speed increases, but thermal stress on the system increases
Solution Approach 1:
The patent uses periodic charging and discharging cycles to manage thermal stress. By alternating between charging (which generates heat) and discharging (which allows cooling), the system can apply higher charging currents to reduce charging time while preventing excessive thermal accumulation through the periodic rest periods during discharging.
Solution Approach 2:
The patent maintains continuous useful action by ensuring that during discharging intervals, the battery serves a useful function (powering a load or regenerating energy) rather than simply resting. This allows the system to manage thermal stress while maintaining productive operation throughout the entire charging-discharging cycle.
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 reduces charging time by minimizing internal resistance and thermal load, allowing higher charging currents and faster charging.
Implementation Method 1
A negative voltage pulse can be regarded as a relaxation pulse that reduces the force with which the charge carriers are pressed against the separator
Implementation Method 2
charge carriers, such as lithium ions, pass through the openings or pores of the separator
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
According to a method for charging an accumulator unit (2) during a plurality of successive charging intervals, at least one pulse parameter is determined by means of a computing unit (4) depending on at least one state variable of the accumulator unit (2) and/or depending on at least one material parameter of the accumulator unit (2). During the charging intervals, at least one voltage pulse (9, 9a, 9b) of a time-dependent charging voltage is generated depending on the at least one pulse parameter.