Battery Deterioration Feedback Control for Longer Cell Life

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Solution Overview

Problem

Existing secondary battery control devices are unable to effectively prolong the life of secondary batteries based on their deterioration states.

Innovation Solution

A secondary battery control device that calculates the degree of deterioration for each member factor of the secondary battery, such as positive electrode use rate, negative electrode use rate, and negative electrode capacity deviation, and adjusts the operating conditions accordingly to prolong battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the secondary battery is used continuously without control, then productivity is improved, but the battery life deteriorates due to deterioration

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidbattery life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The control device calculates the degree of deterioration of member factors based on charge and discharge curves, and uses this feedback information to adjust operating conditions dynamically. The system continuously monitors battery state and modifies charging/discharging parameters based on calculated deterioration levels, creating a closed-loop control system that balances productivity and battery life.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control device dynamically adjusts operating conditions based on real-time deterioration calculations. Instead of fixed operating parameters, the system continuously adapts charging/discharging rates, voltage limits, and current parameters according to the calculated deterioration state of member factors, enabling flexible operation that preserves battery life while maintaining productivity.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the charging upper limit voltage is increased to improve productivity, then charging speed is improved, but the deterioration of the secondary battery accelerates

Engineering Contradiction:
Improvecharging speedVSAvoidbattery deterioration resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device calculates the degree of deterioration of member factors and dynamically changes operating parameters including charging upper limit voltage based on these calculations. When deterioration of positive electrode active material or other member factors is detected, the system adjusts voltage parameters to optimize the balance between charging speed and battery durability.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the discharge lower limit voltage is decreased to increase capacity utilization, then energy storage utilization is improved, but the deterioration of the secondary battery accelerates

Engineering Contradiction:
Improveenergy storage capacityVSAvoidbattery deterioration resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The control device dynamically adjusts the discharge lower limit voltage parameter based on calculated deterioration degrees of member factors. When deterioration is detected, the system modifies voltage parameters to prevent excessive discharge that would accelerate degradation, while still maximizing usable capacity within safe limits.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3518372B1Secondary battery control device
Publication Date: 2025.04.23 VEHICLE ENERGY JAPAN INC
  • EP3518372B1 patent drawingFigure 1
  • EP3518372B1 patent drawingFigure 2(a)~2(c)
  • EP3518372B1 patent drawingFigure 3

AI summary

Life of a secondary battery has not been able to be prolonged according to deterioration of the secondary battery. In step S17, whether a difference between an average value of a negative electrode capacity deviations dn1 calculated in step S15 and a negative electrode capacity deviation dn2 calculated in step S16 is larger than a predetermined value D is determined. In a case where the average value of the measured negative electrode capacity deviations dn1 is larger than the ideal negative electrode capacity deviation dn2, and deterioration of the negative electrode capacity deviation dn1 is proceeding, a secondary battery 10 is controlled to operate at a high voltage in next step S18. With the control, the deterioration of the negative electrode capacity deviation dn1 is suppressed and the life of the secondary battery 10 is prolonged. Further, in a case where an average value of the measured positive electrode use rates mp1 is lower than an ideal positive electrode use rate mp2, and the deterioration of the positive electrode use rate mp1 is proceeding, an upper limit current of the secondary battery 10 is lowered and the secondary battery 10 is controlled to operate in step S20. With the control, the deterioration of the positive electrode use rate mp1 is suppressed, and the life of the secondary battery 10 is prolonged.