Rechargeable Cell Voltage Control for Aging Mitigation
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Solution Overview
Problem
Rechargeable energy storage devices, such as double-layer capacitors and Li-ion storage devices, face reduced service life due to manufacturing variations affecting internal resistance and storage capacity, leading to uneven heating and voltage distribution, which accelerates aging and potential failure.
Innovation Solution
Monitoring and adjusting the voltage of each storage cell by discharging it slightly when temperature or capacity falls below reference levels to maintain optimal operating conditions, thereby extending the service life by reducing voltage to counteract temperature and capacity-related stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the rechargeable energy store operates with storage cells having manufacturing variations, then the device can be produced cost-effectively, but the service life decreases due to uneven aging and temperature distribution
Solution Approach 1:
The patent applies local quality by implementing cell-specific monitoring and control measures. Each storage cell is equipped with individual temperature sensors and voltage monitoring, allowing differentiated treatment of cells based on their specific conditions. The control unit adjusts charging currents and discharging operations on a per-cell basis, addressing the unique characteristics of each cell rather than treating all cells uniformly.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting operating parameters such as charging current, discharging current, and voltage thresholds based on real-time cell conditions. The control unit modifies these parameters in response to temperature variations and capacity measurements, optimizing the operation of each cell to extend service life while maintaining manufacturing simplicity.
2Use of energy by moving object
If the operating voltage of storage cells is maintained at high levels, then the energy density and performance are improved, but the service life decreases due to accelerated aging and overheating
Solution Approach 1:
The patent applies dynamics by implementing dynamic voltage and current adjustment during charging and discharging operations. The control unit continuously monitors cell voltage, temperature, and capacity, and dynamically modifies operating parameters to prevent excessive voltage levels that would accelerate aging. This allows the system to maintain high energy density when conditions permit while protecting cell longevity when temperature or capacity indicators suggest risk.
Solution Approach 2:
The patent employs feedback mechanisms through continuous monitoring of cell voltage, temperature, and capacity by sensors connected to the control unit. This feedback information is used to adjust charging and discharging operations in real-time, preventing voltage levels that would compromise service life while maximizing energy utilization when conditions are favorable.
3Productivity
If the charging current is increased to reduce charging time, then the productivity is improved, but the temperature increases and service life decreases
Solution Approach 1:
The patent applies dynamics by implementing dynamic current adjustment during charging operations. The control unit monitors cell temperature in real-time and dynamically modifies charging current levels accordingly. When temperature remains within acceptable ranges, higher charging currents are permitted to maintain productivity. When temperature approaches critical thresholds, the current is automatically reduced to prevent thermal damage.
Solution Approach 2:
The patent employs periodic action through intermittent charging pulses and rest periods. The charging process is structured in cycles with varying current levels, allowing heat dissipation during lower-current intervals while maintaining overall charging efficiency. This periodic approach prevents continuous high-temperature exposure that would accelerate aging.
4Productivity
If the discharge depth is increased to maximize energy utilization, then the productivity is improved, but the service life decreases due to deeper stress on storage cells
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting discharge voltage thresholds and current levels based on real-time cell capacity measurements. The control unit modifies discharge parameters to optimize the balance between energy utilization and cell stress. Cells with higher remaining capacity can discharge to lower voltage thresholds, while cells showing signs of degradation maintain higher minimum voltage levels.
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 method significantly extends the service life of rechargeable energy storage devices by evenly distributing aging and preventing premature failure, ensuring the weakest cell is not overwhelmed, while maintaining overall system voltage and performance.
Implementation Method 1
rechargeable energy storage device, such as in particular a double-layer capacitor, a Li-ion storage device or an NiMH storage device which has a number of storage cells
Implementation Method 2
storage cells that are essentially the same vary, for example, with regard to their storage capacity and their internal resistance. This leads to different warming at the same load
Data Source
AI summary
The invention relates, in particular, to a method for extending the useful life of a rechargeable energy store for use in a motor vehicle, such as for example, a double layer capacitor, a Li-ion store, a Li-ion capacitor or a NiMH store with several storage cells. According to the invention, the useful life of the energy store may be extended whereby the temperature of each storage cell is measured. Should the temperature of a storage cell exceed a reference value for the temperature of the storage cell the storage cell is partially discharged and the voltage thereof thus reduced.