NiMH Battery Control System for Saddle Vehicle Memory Effect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nickel-metal hydride batteries exhibit reduced charging efficiency at high temperatures and output at low temperatures, along with hysteresis and memory effects, making stable charge/discharge control over a wide State Of Charge (SOC) range challenging.
Innovation Solution
A battery control system that selects SOC use ranges based on temperature, using a control circuit to manage charging and discharging by detecting voltage and calculating SOC, thereby precisely grasping the memory effect and adjusting the lower limit voltage to optimize battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charging/discharging is limited to a narrow SOC range (e.g., 40-60%) to achieve stable control, then charge/discharge control stability is improved, but battery performance utilization is worsened
Solution Approach 1:
The patent applies dynamics by making the SOC use range adjustable rather than fixed. The control circuit dynamically selects between a first SOC use range (narrower, e.g., 40-60%) for stable control and a second SOC use range (wider, e.g., 20-80%) for better performance utilization. This dynamic adaptation allows the system to switch between stability and productivity based on operational requirements, resolving the contradiction between control stability and battery performance utilization.
2Productivity
If charging/discharging is performed over a wide SOC range to make effective use of battery performance, then battery performance utilization is improved, but control complexity is worsened due to hysteresis and memory effects
Solution Approach 1:
The patent applies segmentation by dividing the battery's operating SOC range into multiple distinct use ranges. The first SOC use range (e.g., 40-60%) is segmented for stable control with reduced hysteresis and memory effects, while the second SOC use range (e.g., 20-80%) is segmented for broader performance utilization. The control circuit selectively activates appropriate segments based on operational needs, making wide-range operation manageable by treating it as coordinated control of multiple smaller, more controllable segments.
3Device complexity
If a single SOC use range is used for all conditions, then device complexity is reduced, but adaptability to different temperature conditions is worsened
Solution Approach 1:
The patent applies universality by designing a control system that can perform multiple functions through a single unified architecture. The control circuit is capable of selecting between multiple SOC use ranges (first and second ranges) depending on temperature conditions and operational requirements. This multi-functional capability allows the same control system to adapt to various temperature conditions (cold, moderate, hot) and different operational modes (stable control vs. performance optimization) without requiring separate dedicated control systems for each condition.
Data Source
Figure 1
Figure 2
Figure 3
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 depending on the condition of use, and controls the charging/discharging of the nickel-metal hydride battery 40 in accordance with the selected SOC use range. The microcontroller 61 determines whether the current SOC of the nickel-metal hydride battery 40 is equal to a predetermined SOC that corresponds to the lower limit of an SOC use range 130. When it is determined that the current SOC is equal to the predetermined SOC, information regarding the memory effect of the nickel-metal hydride battery 40 is obtained. The microcontroller 61 controls the discharging of the nickel-metal hydride battery 40 using the obtained information regarding the memory effect.