EV Battery SOC Range Control for Lower Degradation
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Solution Overview
Problem
Existing methods for managing secondary batteries in electric vehicles prioritize traveling performance over degradation suppression, leading to insufficient control over battery degradation, which can limit the battery's capacity to travel necessary distances.
Innovation Solution
A management device that measures current and temperature, accumulates use history, and adjusts the state of charge (SOC) range by increasing the upper limit or decreasing the lower limit based on cycle and storage degradation characteristics to minimize degradation while ensuring necessary capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the use range of SOC is expanded to increase battery capacity for necessary travel distance, then the battery capacity becomes sufficient, but the degradation rate of the secondary battery accelerates
Solution Approach 1:
The patent applies dynamics by making the SOC use range adjustable and adaptive rather than fixed. The control unit dynamically modifies the upper and lower limit values of the SOC use range based on real-time battery status, temperature conditions, and degradation characteristics, allowing the system to optimize between capacity utilization and degradation suppression under varying operating conditions
Solution Approach 2:
The patent changes physical parameters by adjusting the SOC limit values (upper and lower bounds) based on temperature conditions and degradation characteristics. The system modifies these parameter thresholds to balance capacity requirements with degradation control, selecting optimal parameter settings that minimize degradation while ensuring sufficient travel distance
2Quantity of substance
If the upper limit value of SOC is increased to expand use range, then the battery capacity increases, but the cycle degradation rate increases
Solution Approach 1:
The patent applies parameter changes by adjusting the upper limit value of SOC based on temperature conditions and cycle degradation characteristics. When temperature is high, the system sets a lower upper limit value to reduce cycle degradation, while when temperature is low, it allows a higher upper limit value to maximize capacity utilization, thus optimizing the balance between capacity and degradation control
3Quantity of substance
If the lower limit value of SOC is decreased to expand use range, then the battery capacity increases, but the storage degradation rate increases
Solution Approach 1:
The patent applies parameter changes by adjusting the lower limit value of SOC based on temperature conditions and storage degradation characteristics. When temperature is high, the system sets a higher lower limit value to reduce storage degradation, while when temperature is low, it allows a lower lower limit value to maximize capacity utilization, thus optimizing the balance between capacity and degradation control
Data Source
AI summary
When a use range of an SOC (State Of Charge) of a secondary battery is expanded, the use range of the SOC is expanded by increasing an upper limit value or decreasing a lower limit value of the use range of the SOC. The increasing the upper limit value or decreasing the lower limit value of the use range of the SOC is determined to a side causing a smaller increase in a degradation rate of the secondary battery, based on at least one of a cycle degradation characteristic that defines a cycle degradation rate in accordance with the use range of the SOC and a current rate of the secondary battery and a storage degradation characteristic that defines a storage degradation rate in accordance with the SOC and a temperature of the secondary battery, and a typical use condition of the secondary battery based on a use history of the secondary battery.