Hybrid Battery SoC Reset Using Standby Cross-Charging

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Solution Overview

Problem

Existing methods for determining and recalibrating the state of charge of hybrid vehicle batteries, particularly lithium-iron-phosphate batteries, face challenges due to voltage plateau regions making voltage-based gauging inaccurate and coulometric methods prone to drift, which complicates hybrid energy management and increases CO2 footprint.

Innovation Solution

A method that involves charging the first battery using the second battery during a vehicle standby phase, measuring voltage, and comparing it to threshold values to determine maximum and minimum state of charge, allowing for recalibration without disrupting driving energy management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If voltage measurement is used to determine state of charge, then measurement is simple, but accuracy is poor in plateau regions

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidstate of charge accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses an intermediary substance (salt) that changes color in response to moisture content. This color-changing salt acts as a mediator between the moisture in the packaging material and the visual indicator, allowing accurate moisture detection without complex electronic measurement systems. The salt's color change provides a clear visual signal that is easy to observe while accurately reflecting the moisture state.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If coulometric measurement is used to determine state of charge, then accuracy is improved, but drift occurs over time requiring recalibration

Engineering Contradiction:

Improvestate of charge accuracyVSAvoidmeasurement stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs self-calibration by utilizing the vehicle's existing charging infrastructure. During normal charging operations, the system automatically references known good states (fully charged or discharged conditions) to recalibrate the coulometric measurements, eliminating drift without requiring external intervention or specialized equipment. The measurement system calibrates itself using the charging process already inherent in battery operation.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If battery recalibration is performed during driving phase, then energy management is disrupted, but state of charge accuracy is maintained

Engineering Contradiction:

Improvestate of charge accuracyVSAvoidenergy management efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system performs recalibration actions in advance during the vehicle's standby phase, before the driving phase begins. By completing the recalibration process while the vehicle is parked and not in use, the system ensures measurement accuracy is maintained without interfering with subsequent driving operations or energy management during active phases.

Inventive Principle:

Principle #10Preliminary action

4Measurement precision

If kinetic energy harvesting is avoided during recalibration, then state of charge accuracy is improved, but CO2 footprint increases

Engineering Contradiction:

Improvestate of charge accuracyVSAvoidCO2 footprint

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system converts the otherwise wasted kinetic energy during braking into useful energy for battery recalibration. By harvesting the kinetic energy that would normally be lost during deceleration and using it to power the recalibration process, the system simultaneously maintains measurement accuracy and reduces CO2 emissions, turning a potentially harmful waste into a beneficial resource.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables accurate recalibration of battery gauges during standby phases, optimizing energy management during driving phases by avoiding complex computations and ensuring reliable state of charge determination.

Implementation Method 1

measuring the value of the open-circuit voltage of the battery

Methodology Applied

Scientific EffectOpen-circuit voltage measurement: Ohm's Law

Implementation Method 2

via a coulometric measurement, i.e. by counting the ampere-hours (Ah) entering and leaving the battery

Methodology Applied

Scientific EffectCoulometric measurement: Coulomb's Law

Data Source

PatentUS20250050863A1Method for determining and resetting the state of charge of the batteries of a hybrid vehicle

Publication Date: 2025.02.13 AMPERE SAS

AI summary

A method is for determining and resetting the state of charge of at least one battery of a hybrid vehicle including a first battery, a second battery and a heat engine. The method includes, during a standby phase of the vehicle, a first step of charging the first battery via the second battery, during which: (i) the first battery is charged; (ii) the value of its voltage is measured; (iii) the value of the voltage of the first battery is compared with a threshold voltage value corresponding to a maximum state of charge of the first battery; and (iv) when the threshold voltage value is reached, stopping the charging of the first battery, determining that it is in a maximum state of charge and setting a value of its state of charge to maximum state of charge, and otherwise continuing to charge.