Battery Cell Deactivation via Electronic Switching

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Solution Overview

Problem

Existing battery pack systems fail to effectively disconnect faulty or weak short-circuited cells during emergency situations, such as vehicle crashes or high thermal events, leading to potential electrocution risks and reduced battery longevity, and lack a cost-effective method for identifying and isolating problematic cells.

Innovation Solution

An intelligent architecture is implemented, where every cell in the battery pack is connected to an electronically controlled switch and an embedded processor, capable of detecting weak shorts by monitoring voltage balancing and self-discharge rates, allowing for the isolation of faulty cells through a network of switches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If mechanical breakable conductors are used to disconnect battery cells during crashes, then physical protection is provided, but the mechanical strength is excessive and prevents breaking during short circuit events

Engineering Contradiction:
Improveprotection from high voltage exposureVSAvoidmechanical strength of conductor
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent replaces mechanical breakable conductors with an electronically controlled switching system. A control device monitors cell voltage and current to detect weak short circuits, then electronically opens a switch to disconnect the faulty cell. This substitution allows disconnection based on electrical parameters rather than mechanical force, enabling response to weak short circuits that mechanical systems cannot detect.

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

Solution Approach 2:

The system implements feedback by continuously monitoring cell voltage and current through sensors, comparing readings against threshold values, and automatically actuating the switch when abnormal conditions are detected. This closed-loop control enables real-time detection and isolation of weak short circuits without mechanical intervention.

Inventive Principle:
Principle #23Feedback

2Difficulty of detecting and measuring

If electronic switching systems are implemented to detect weak shorts, then detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvedetection of weak short circuitsVSAvoidcomplexity of electronic control system
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The control device performs multiple functions: it monitors voltage and current across all battery cells, detects weak short circuits through threshold comparison, and actuates the switching mechanism. By consolidating these functions into a single multi-functional control unit, the system reduces overall complexity compared to having separate dedicated components for each function.

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

Solution Approach 2:

The system uses the battery pack's existing electrical parameters (voltage and current) for detection, requiring no external sensors or additional measurement infrastructure. The control device leverages the natural electrical signals present in the battery system to identify weak shorts, eliminating the need for complex external detection equipment.

Inventive Principle:
Principle #25Self-service

3Reliability

If individual cell monitoring is implemented, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvesafety and battery longevityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the monitoring and control functions into a single integrated control device that manages multiple battery cells through shared voltage and current sensors. By merging detection and actuation functions into one unit rather than implementing separate systems for each cell, the manufacturing cost is reduced while maintaining individual cell monitoring capability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2171824B1Method of deactivating faulty battery cells
Publication Date: 2016.01.27 TESLA INC
  • EP2171824B1 patent drawingFigure 1~3

AI summary

A method and apparatus for deactivating a bad battery cell from a battery pack for an energy storage system of an electric vehicle is disclosed. The apparatus and methodology includes a clamshell member arranged at an end of the cells and a printed circuit board arranged adjacent to the clamshell member. A collector plate is arranged adjacent to the printed circuit board and a switch is arranged on the printed circuit board. A wire bond is arranged between the switch and one of the cells and a second wire bond is arranged between the switch and the collector plate. The plurality of switches will allow for the identification of the one individual cell having a weak short circuit within the battery pack. Upon identification of the cell with the weak short circuit that cell will have its switch placed in an open position thus electrically isolating the faulty or bad cell from the battery pack.