Battery Pack Internal Short Detection via Cell Segmentation

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Solution Overview

Problem

Identifying internal shorts in battery packs is challenging due to their potential to cause performance degradation and hazardous conditions, especially during charging, and existing methods are not sufficiently accurate or reliable for large-scale battery systems like those used in electric vehicles.

Innovation Solution

A fault-detection system that includes a data-acquisition and monitoring system to identify anomalous conditions in battery packs during charging, comparing these conditions against predetermined profiles to establish an internal-short state, which can prevent unsafe charging conditions by terminating the charge and initiating diagnostic tests.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional monitoring methods are used for battery packs, then device complexity is reduced, but measurement precision and reliability of internal short detection deteriorate

Engineering Contradiction:
Improveinternal short detection accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The battery pack is divided into multiple individual cells, each equipped with its own monitoring circuit that measures voltage, current, and temperature independently. This segmentation allows precise detection of internal shorts in specific cells while keeping each monitoring unit relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A microcontroller unit acts as an intermediary between the distributed sensor nodes and the central control system. It collects data from multiple sensors, performs preliminary analysis, and communicates with the charging system, thereby reducing overall system complexity while maintaining high detection precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If continuous monitoring of all battery parameters is implemented, then reliability of hazard detection is improved, but use of energy increases

Engineering Contradiction:
Improvehazard detection reliabilityVSAvoidenergy consumption by monitoring system
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The monitoring system performs measurements at periodic intervals rather than continuously. During normal charging operation, parameters are sampled at predetermined time intervals, reducing energy consumption while maintaining reliable hazard detection capability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The monitoring system uses the existing charging current and voltage as part of its measurement inputs, rather than requiring separate dedicated measurement circuits for all parameters. This self-service approach reduces the energy overhead of the monitoring system.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If detailed individual cell data is collected and evaluated, then measurement precision for fault identification is improved, but difficulty of detecting and measuring increases

Engineering Contradiction:
Improvefault identification accuracyVSAvoiddata evaluation complexity
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system continuously compares measured cell parameters against expected values and provides feedback when deviations are detected. This feedback mechanism guides the evaluation process, focusing computational resources on anomalous conditions rather than uniformly processing all data, thereby reducing overall evaluation difficulty.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Complex data evaluation and pattern recognition tasks are performed by a microcontroller unit using embedded algorithms, replacing what would otherwise require complex manual analysis or sophisticated external measurement equipment. This substitution simplifies the physical measurement system while maintaining high fault identification precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10534028B2Methodology for charging batteries safely
Publication Date: 2020.01.14 TESLA INC
  • US10534028B2 patent drawing
  • US10534028B2 patent drawing
  • US10534028B2 patent drawing

AI summary

An apparatus and method for identifying a presence of a short circuit in a battery pack. A fault-detection apparatus for a charging system that rapidly charges a collection of interconnected lithium ion battery cells, the safety system includes a data-acquisition system for receiving a set of data parameters from the collection while the charging system is actively charging the collection; a monitoring system evaluating the set of data parameters to identify a set of anomalous conditions; and a controller comparing the set of anomalous conditions against a set of predetermined profiles indicative of an internal short in one or more cells of the collection, the controller establishing an internal-short state for the collection when the comparing has a predetermined relationship to the set of predetermined profiles.