NiMH Battery SOC Range Control Across Temperature Hysteresis
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Solution Overview
Problem
Nickel-metal hydride batteries exhibit reduced charging efficiency at high temperatures and output at low temperatures, along with hysteresis in voltage and State Of Charge (SOC) relationships, making stable charge/discharge control over a wide SOC range challenging.
Innovation Solution
A battery control system that adjusts SOC use ranges based on temperature, using a memory to store multiple SOC ranges and a control circuit to select and manage these ranges, ensuring stable charging and discharging across a wide SOC range by preventing extreme SOC levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charging/discharging is performed over a narrow SOC range (e.g., 40-60%), then stable charge/discharge control is achieved, but the effective use of battery performance is reduced
Solution Approach 1:
The patent applies dynamics by making the SOC use range adjustable rather than fixed. The control circuit dynamically selects different SOC use ranges based on temperature conditions, transitioning from a narrow range (40-60%) under high temperature to a wider range under low temperature, thereby adapting the system to varying operating conditions to simultaneously achieve stability and performance utilization
Solution Approach 2:
The patent changes the parameter of SOC use range based on temperature. By detecting temperature and selecting different SOC ranges from stored information, the system modifies its operational parameters to match environmental conditions, resolving the contradiction between control stability and performance utilization
2Productivity
If charging/discharging is performed over a wide SOC range, then effective use of battery performance is improved, but charge/discharge control stability deteriorates
Solution Approach 1:
The system changes the SOC use range parameter based on temperature detection. Under low temperature conditions where the battery can tolerate wider SOC variations, the system expands the SOC range to improve performance utilization. Under high temperature conditions, it narrows the range to maintain control stability, thus resolving the contradiction through conditional parameter adjustment
3Productivity
If SOC use range is expanded to improve battery performance utilization, then productivity increases, but the influence of temperature-related efficiency reduction and output reduction becomes more significant
Solution Approach 1:
The patent applies local quality by applying different SOC use ranges for different temperature conditions. Instead of a uniform approach, the system tailors the SOC range to local temperature conditions - using a narrower range (40-60%) when temperature is high to minimize efficiency loss, and a wider range when temperature is low to maximize performance utilization
Solution Approach 2:
The system changes the SOC use range parameter based on temperature detection. By detecting temperature and selecting different SOC ranges from stored information, the system modifies its operational parameters to match environmental conditions, resolving the contradiction between performance utilization and temperature influence
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
Enables effective use of nickel-metal hydride batteries by maintaining stable performance across varying temperatures, suppressing output reduction at low temperatures and efficiency loss at high temperatures, allowing for efficient charge/discharge over a wide SOC range.
Implementation Method 1
receives information regarding a temperature of the nickel-metal hydride battery detected by a temperature sensor
Implementation Method 2
while generating power, the nickel-metal hydride battery can store electric power generated by the rotating electrical machine
Data Source
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AI summary
A battery control system 6 according to an embodiment controls charging/discharging of a nickel-metal hydride battery 40 having a hysteresis characteristic for a relationship between voltage and SOC. A microcontroller 61 selects one of a plurality of SOC use ranges having different SOC upper and lower limits, and controls charging/discharging of the nickel-metal hydride battery 40. The microcontroller 61 changes an SOC use range to be selected from among a plurality of SOC use ranges depending on the temperature of the nickel-metal hydride battery 40.