Battery SOC Estimation Using a Simplified Many-Particle Model

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for estimating the state of charge (SOC) of storage batteries using the many particle model increase computation load on processors, particularly in devices with limited resources like vehicle-mounted ECUs, due to high memory usage and complex calculations.

Innovation Solution

A simplified many particle model is employed, where charge carriers are assumed equal among particles in each phase, allowing collective calculation of overvoltages and reaction current densities, reducing the computation load while maintaining high accuracy in SOC estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the many particle model is used to estimate SOC with high accuracy, then the measurement precision is improved, but the computation load on the processor increases excessively

Engineering Contradiction:
ImproveSOC estimation accuracyVSAvoidcomputation load
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The positive electrode active material is divided into multiple particles, each representing a different reaction sequence. This segmentation allows the model to capture individual particle behavior while still using simplified calculations for each particle, balancing accuracy with computational efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a particle number as a new parameter to distinguish particles by their reaction sequence. By using this parameter to organize and categorize particle behavior, the model achieves higher SOC estimation accuracy without proportionally increasing computational complexity, as particles can be processed in groups or sequences.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If thousands of particles are used in the many particle model, then the SOC estimation accuracy is improved, but the memory usage increases excessively

Engineering Contradiction:
ImproveSOC estimation accuracyVSAvoidmemory usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The model segments particles into distinct groups based on reaction sequences, allowing efficient memory management. Instead of treating all particles uniformly, the segmentation enables reusable calculation patterns across particle groups, reducing overall memory requirements while maintaining high particle counts for accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses representative particles or particle groups to model the behavior of multiple particles with similar characteristics. By creating simplified representations (copies) of particle behavior patterns, the system can simulate thousands of particles without requiring proportional memory resources for each individual particle.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20250020724A1Method of managing storage battery and battery management system
Publication Date: 2025.01.16 TOYOTA JIDOSHA KK
  • US20250020724A1 patent drawing
  • US20250020724A1 patent drawing
  • US20250020724A1 patent drawing

AI summary

A positive electrode active material includes: a rich phase; a poor phase; and a two-phase coexistence phase in which the rich phase and the poor phase coexist. A method of managing a battery includes, in a many particle model in which the positive electrode active material is represented by a plurality of particles each distinguished by a particle number indicating a reaction sequence of the positive electrode active material, assuming that the charge carriers are equal in content among one or more particles belonging to each of the rich phase, the poor phase, and the two-phase coexistence phase: calculating an overvoltage of each of the particles for each of the phases; calculating a reaction current density based on the overvoltage for each of the phases; and estimating an SOC of the storage battery based on the reaction current density in each of the phases.