Battery SOC Control to Reduce Crystalline Carbon Phase Transitions
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Solution Overview
Problem
Existing energy storage systems face challenges in suppressing battery deterioration due to continuous small charge/discharge cycles, particularly affecting the negative electrode, which leads to particle size changes and distortion, reducing battery life.
Innovation Solution
An energy storage apparatus with a charge/discharge control method that maintains the state of charge (SOC) of secondary batteries between 50% and 70% to minimize phase transitions in crystalline carbon negative electrodes, using a control unit to alternate between low and high SOC ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small charge/discharge cycles are continuously repeated in secondary batteries, then the energy storage apparatus can respond to frequency fluctuations, but the battery deteriorates due to phase transitions in crystalline carbon
Solution Approach 1:
The patent applies preliminary action by pre-charging the secondary battery to a state of charge of 70% or more before it is needed for frequency fluctuation response. This advance preparation ensures that the battery starts in a high SOC state, which prevents phase transitions in crystalline carbon during subsequent small charge/discharge cycles, thereby extending battery life while maintaining the capability to respond to frequency fluctuations when needed.
2Productivity
If high SOC standby type battery is used for discharging and low SOC standby type battery for charging, then charge/discharge operations can be optimized, but recovery operations become difficult when small charge/discharge is continuously repeated
Solution Approach 1:
The system applies preliminary action by maintaining the secondary battery in a high SOC state (70% or more) as a preparatory measure before frequency fluctuation events occur. This ensures that when small charge/discharge cycles are needed for frequency response, the battery starts from an optimal state that allows easy recovery operations afterward, eliminating the difficulty of returning to original standby SOC after continuous small cycles.
Solution Approach 2:
The patent applies parameter changes by controlling the state of charge parameter to be 70% or more before frequency fluctuation response. This parameter control strategy changes the operational characteristics of the battery, enabling it to undergo small charge/discharge cycles without phase transitions, thus facilitating easier recovery operations while maintaining charge/discharge efficiency.
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 the frequency of phase transitions, thereby minimizing negative electrode deterioration and extending the battery's cycle life.
Implementation Method 1
This approach effectively extends the cycle life of secondary batteries by reducing the number of phase transitions in crystalline carbon
Data Source
AI summary
An energy storage apparatus includes a plurality of secondary batteries each including a negative electrode including crystalline carbon; and a charge/discharge control unit that controls charge/discharge of the plurality of secondary batteries so that a state of charge does not fall within a range of 50% or more and 70% or less.