Battery EIS Sense Cable Layout for EMI-Canceling Measurements

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Solution Overview

Problem

Existing battery measurement systems face errors due to electromagnetic interference caused by current loops in battery cables, which degrade electrochemical impedance spectroscopy (EIS) signals, particularly at the module or pack level, making it difficult to accurately assess battery health and performance.

Innovation Solution

A battery measurement system with sense cables disposed across battery cells to create counter-current loops that cancel out electromagnetic interference, allowing simultaneous measurement of two cells to reduce noise and enhance signal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional cabling is used for battery measurements, then the system structure is simple, but electromagnetic interference degrades measurement accuracy

Engineering Contradiction:

Improveimpedance measurement accuracyVSAvoidelectromagnetic interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by configuring sense cables to carry current in the opposite direction to the battery internal resistance current flow. This creates a counteracting electromagnetic field that cancels out the harmful electromagnetic interference generated by the measurement current itself, thereby improving impedance measurement accuracy without requiring complex shielding or filtering components.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful electromagnetic interference generated by the interrogatory current into a beneficial effect. By deliberately routing the sense cable to carry the same current in the opposite direction, the system uses the interference-generating current itself to create a canceling electromagnetic field, transforming the harmful factor into a useful cancellation mechanism that improves measurement precision.

Inventive Principle:

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

2Productivity

If multiple batteries are measured simultaneously, then productivity increases, but electromagnetic interference from multiple current loops increases measurement errors

Engineering Contradiction:

Improvemeasurement throughputVSAvoidbattery health measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent extends the preliminary anti-action principle to multi-battery measurements by configuring sense cables for each battery to carry current in opposition to the respective battery's internal resistance current. This creates individual counteracting electromagnetic fields for each measurement channel, allowing simultaneous measurement of multiple batteries while maintaining accuracy by canceling interference from each current loop independently.

Inventive Principle:

Principle #9Preliminary anti-action

3Measurement precision

If sense cables are routed to cancel electromagnetic interference, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:

Improvevoltage and current reading accuracyVSAvoidcable routing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements preliminary anti-action through a straightforward cable routing strategy where sense cables are positioned to carry current in the opposite direction to the battery's internal resistance current flow. This approach achieves electromagnetic interference cancellation through simple geometric arrangement rather than complex active compensation circuits, maintaining relatively low device complexity while significantly improving measurement precision.

Inventive Principle:

Principle #9Preliminary anti-action

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 approach significantly reduces electromagnetic interference, enabling accurate impedance measurements and diagnostics of battery health, temperature, and state of charge, thereby improving battery system performance and enabling timely replacement of defective cells.

Implementation Method 1

each sense cable of the plurality of sense cables is disposed across the corresponding battery such that the interrogatory current flows in a conduction channel in the corresponding battery in a first direction and in the corresponding cable in a second direction substantially opposite of the first direction

Methodology Applied

Scientific EffectElectromagnetic interference cancellation: Electromagnetic Induction

Data Source

PatentUS12618871B2Apparatuses and methods for electrochemical impedance spectroscopy measurements

Publication Date: 2026.05.05 ANALOG DEVICES INT UNLTD CO

AI summary

Aspects of the present disclosure include a battery measurement system having a plurality of capacitors, a plurality of probes each electrically coupled with a corresponding capacitor of the plurality of capacitors and a corresponding battery of a plurality of batteries, a controller configured to measure, via the plurality of probes, a plurality of voltages associated with the plurality of batteries in response to an interrogatory current, and a plurality of sense cables each associated with the corresponding battery of the plurality of batteries, wherein each sense cable of the plurality of sense cables is disposed across the corresponding battery such that the interrogatory current flows in a conduction channel in the corresponding battery in a first direction and in the corresponding cable in a second direction substantially opposite of the first direction.