Battery Capacity Indicator Limiting Charge Discharge Fluctuations
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Solution Overview
Problem
Existing secondary battery remaining capacity estimation methods often result in discrepancies between indicated and actual capacity changes, causing odd readings for drivers, particularly during charging and discharging.
Innovation Solution
A secondary battery remaining capacity estimating apparatus that includes a charge/discharge determining section, a remaining capacity estimating section, and a limiting section to prevent excessive decreases or increases in indicated capacity, ensuring accurate representation of the battery's state by selecting between current integration and open circuit voltage methods based on charging or discharging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the remaining capacity is estimated using the current integration method or open circuit voltage method, then the remaining capacity can be quantified, but the indicated estimation value may change differently from the actual remaining capacity (e.g., decreasing during charging or increasing during discharging)
Solution Approach 1:
The system continuously monitors the charge/discharge state of the battery and uses this feedback to control the updating of the indicated remaining capacity. When charging is detected, the system prevents the indicated capacity from decreasing even if the estimation value decreases. When discharging is detected, the system prevents the indicated capacity from increasing even if the estimation value increases. This feedback mechanism ensures the indicated value consistently reflects the actual battery state.
Solution Approach 2:
The system dynamically adjusts the updating rule of the indicated remaining capacity based on the charge/discharge state. The update behavior changes depending on whether the battery is charging or discharging, making the system adaptive to different operational conditions rather than using a fixed update rule.
2Productivity
If the indicated remaining capacity is updated continuously based on estimation values, then the estimation can track battery state changes, but the indicated value may show unnatural behavior that confuses drivers
Solution Approach 1:
The system takes preliminary action to prevent unnatural behavior by detecting the charge/discharge state before the estimation value can cause contradictory changes. When charging is detected, the system preemptively prevents the indicated capacity from decreasing. When discharging is detected, it preemptively prevents the indicated capacity from increasing, thus avoiding unnatural behavior before it occurs.
Solution Approach 2:
The system uses feedback from the charge/discharge state detection to control the updating behavior of the indicated remaining capacity, ensuring that the indication remains intuitive and consistent with driver expectations during different operational modes.
Data Source
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AI summary
A secondary battery remaining capacity estimating apparatus basically includes a secondary battery (1), a charge/discharge determining section (2005), a remaining capacity estimating section (20), a remaining capacity indicating section (7) and a remaining capacity indication limiting section (21). The charge/discharge determining section (2005) determines if the secondary battery is charging or discharging. The remaining capacity estimating section (20) estimates a remaining electric power capacity of the secondary battery. The remaining capacity indicating section (7) indicates a remaining capacity of the secondary battery based on an estimation value by the remaining capacity estimating section (20). The remaining capacity indication limiting section (21) limits a decrease of a remaining capacity indicated upon determining that the secondary battery is charging and the estimation value will decrease, and limits an increase of a remaining capacity indicated upon determining that the secondary battery is discharging and the estimation value will increase.