Vehicular Control Device for Lithium Deposition Estimation

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Solution Overview

Problem

Existing lithium-ion battery charge control systems, like those described in Japanese Unexamined Patent Application Publication No. 2019-125558 A, face difficulties in accurately detecting regenerative current from electric power steering systems, leading to inaccurate estimation of lithium deposition and delayed reporting of battery change needs due to current sensor detection limitations.

Innovation Solution

A vehicular control device that determines the absolute value of the steering angle and estimates lithium deposition based on vehicle information, including steering angle speed, battery temperature, and state of charge, to accurately report when a lithium-ion battery needs to be changed, even when regenerative current from EPS motors cannot be detected by current sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a current sensor with a large detection cycle (e.g., 100 milliseconds) is used to detect charging current, then the device complexity is reduced, but the measurement precision of regenerative current from EPS motor is insufficient

Engineering Contradiction:

Improvecurrent sensor detection systemVSAvoidregenerative current detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses steering angle information as an intermediary to indirectly detect regenerative current events. Instead of relying on the current sensor to directly detect the short-duration regenerative current, the system uses the steering angle sensor (which has higher measurement precision and faster response) to detect when full-lock steering occurs, then estimates the regenerative current based on this information.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the electrical detection method (current sensor) with a mechanical/physical parameter-based detection method (steering angle sensing). By substituting the direct electrical measurement with indirect detection through steering angle monitoring, the system overcomes the limitation of current sensor detection cycle while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If regenerative current from EPS motor is not detected due to short duration (about 30 milliseconds), then the current sensor can operate with lower specifications, but the estimation accuracy of lithium deposition amount deviates from actual value

Engineering Contradiction:

Improvedetection capability for short-duration currentVSAvoidlithium deposition amount estimation accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The system performs preliminary detection of the condition that generates regenerative current (full-lock steering) before the actual current flows. By monitoring steering angle in advance and identifying when full-lock steering occurs, the system can estimate and account for the regenerative current that will flow, even though the current itself is too brief to be detected by the current sensor.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where steering angle information is continuously monitored and used to adjust the lithium deposition estimation. When full-lock steering is detected through steering angle monitoring, this information feeds back into the estimation algorithm to compensate for the regenerative current effect, ensuring accurate lithium deposition calculation despite the current sensor's inability to directly detect the short-duration current.

Inventive Principle:

Principle #23Feedback

3Device complexity

If charge control is based only on detectable current, then the control system is simpler, but the reliability of battery change timing report is reduced

Engineering Contradiction:

Improvecharge control systemVSAvoidbattery change timing report accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent makes the steering angle sensor serve multiple functions: it not only controls the electric power steering system but also provides data for detecting regenerative current events and estimating lithium deposition. This multi-functional use of the steering angle sensor allows the system to improve reliability without adding dedicated detection hardware, thus maintaining simplicity while enhancing accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11518437B2Vehicular control device, control method, non-temporary storage medium, and vehicle

Publication Date: 2022.12.06 TOYOTA JIDOSHA KK

AI summary

A vehicular control device includes a determining unit configured to determine whether an absolute value of a steering angle as a rotation angle of a steering wheel exceeds a first threshold value, an estimating unit configured to estimate a lithium deposition amount as an amount of lithium metal deposited on the lithium-ion battery by regenerative current flowing into the lithium-ion battery, based on vehicle information obtained from the vehicle, when the determining unit determines that the absolute value of the steering angle exceeds the first threshold value, and a reporting command unit configured to give a command to report that the vehicle is in a first state, based on the lithium deposition amount estimated by the estimating unit.