Battery Control Device Slope-Adjusted Permissible Current Computation

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Solution Overview

Problem

Existing battery control methods fail to accurately compute permissible current in steep change regions of the SOC-OCV curve, leading to excessive safety margins that limit battery output, as they do not account for predicted changes in battery state over time.

Innovation Solution

A battery control device that calculates permissible current by using an absolute value of the slope greater than the present battery characteristic slope, specifically in steep change regions, allowing for accurate prediction of battery information without increasing data requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed permissible current computation method is used without considering steep change regions, then the control method is simple, but the permissible current is excessively limited in steep change regions

Engineering Contradiction:
Improvecontrol method simplicityVSAvoidbattery output
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent applies dynamics by making the permissible current computation adaptive to different SOC regions. The control method dynamically switches between fixed computation (non-steep regions) and slope-adjusted computation (steep regions), allowing the system to optimize battery output based on real-time operating conditions while maintaining simplicity where applicable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the computation parameters based on the SOC region. In steep change regions, the method uses the absolute value of the OCV slope as an additional parameter to adjust the permissible current calculation, whereas in non-steep regions, it uses the conventional fixed computation method, thereby optimizing battery output without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a margin is added to suppress excessive current in steep change regions, then safety is improved, but battery output is excessively limited

Engineering Contradiction:
Improvebattery safetyVSAvoidbattery output
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by implementing different safety margins for different SOC regions. In steep change regions, a moderate margin based on OCV slope is applied to ensure safety, while in non-steep regions, no additional margin is needed, allowing maximum battery output. This localized approach prevents excessive current only where necessary.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The safety margin is made dynamic by adjusting it based on the SOC region. The system automatically applies the slope-based margin only when operating in steep change regions and uses conventional margins elsewhere, thereby maintaining safety without unnecessarily limiting battery output in safe operating regions.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If conventional permissible current computation is used, then the computation is simple, but prediction accuracy of battery state is insufficient in steep change regions

Engineering Contradiction:
Improvecomputation complexityVSAvoidbattery state prediction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the computation parameters based on the SOC region. In steep change regions, it incorporates the absolute value of the OCV slope as an additional parameter to improve prediction accuracy, while in non-steep regions, it uses the conventional simpler computation method, thereby balancing accuracy and complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the SOC range into steep change regions and non-steep regions, applying different computation methods to each segment. This segmentation allows the system to use enhanced computation only where needed for accuracy while maintaining simplicity in other regions, optimizing the balance between complexity and precision.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the same permissible current computation is used in the entire SOC region, then the control method is uniform, but it cannot achieve both safety and high output in steep change regions

Engineering Contradiction:
Improvecontrol method uniformityVSAvoidbattery control adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent makes the control method dynamic by automatically adapting to different SOC regions. The system uniformly applies the appropriate computation method based on real-time SOC position, switching between fixed computation and slope-adjusted computation as needed, thereby achieving both uniformity of implementation and adaptability to specific operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal control method that handles both steep and non-steep regions within a single framework. The method universally checks the SOC region and applies the appropriate computation strategy, making the control system adaptable to various operating conditions while maintaining a unified control architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11084385B2Battery control device, battery system, and vehicle
Publication Date: 2021.08.10 VEHICLE ENERGY JAPAN INC
  • US11084385B2 patent drawing
  • US11084385B2 patent drawing
  • US11084385B2 patent drawing

AI summary

In an existing permissible current computation algorithm, an excessive current is caused to flow by controlling the battery having a steep change region in the battery characteristic. On the other hand, when the current is reduced and the output is suppressed, the battery performance cannot be sufficiently utilized. Moreover, with countermeasures to increase the number of data points, the amount of data increases and thus can not be installed in the microcomputer. A battery control device that computes a permissible current of a battery having a battery characteristic non-steep change region having a small battery characteristic change and a battery characteristic steep change region having a battery characteristic change greater than in the battery characteristic non-steep change region, in which in a case where the battery enters the battery characteristic steep change region after a predetermined time from a present state, a battery characteristic value is calculated by using an absolute value of a slope greater than an absolute value of a slope in the present battery characteristic.