Busbar Sensor Array for Individual Battery Cell Current Monitoring

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Solution Overview

Problem

Existing battery monitoring systems, such as those described in US 9748612, US 2012/0182021 A, KR 2016 0026469 A, EP 2 541 641 A, CN 109 742 821 A, and JP 2004 194410, are limited in their ability to accurately monitor current flow in individual battery cells within a battery pack, requiring invasive modifications and lacking real-time monitoring capabilities.

Innovation Solution

A sensor arrangement comprising an array of magnetic field sensors, such as fluxgates or optically-pumped magnetometers, positioned on a busbar network to non-invasively measure current flow in each busbar link, allowing determination of current magnitude and direction, and a processor to calculate overall current at nodes, enabling real-time monitoring and identification of faulty cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single sensor is used to monitor battery cells, then device complexity is reduced, but measurement precision of individual cell current is insufficient

Engineering Contradiction:
Improvesensor arrangement complexityVSAvoidindividual cell current measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The battery pack is divided into multiple segments, each monitored by a dedicated sensor. The sensor array is segmented to align with individual busbar links, allowing each sensor to measure current in a specific busbar link independently. This segmentation enables precise measurement of individual cell currents while maintaining a relatively simple overall system architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The monitoring system transitions from a single-point measurement to a multi-dimensional array of sensors. By arranging sensors in a two-dimensional pattern that corresponds to the busbar network geometry, the system captures current distribution across multiple spatial dimensions, enabling precise individual cell monitoring without requiring complex invasive modifications to each cell.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If invasive modifications are made to monitor individual cells, then measurement precision is improved, but ease of manufacture and installation deteriorates

Engineering Contradiction:
Improveindividual cell current measurementVSAvoidbattery pack assembly
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The busbar links serve as intermediaries that carry both the electrical current and the magnetic field signature of individual cells. By placing sensors on the busbar links rather than directly on the cells, the system obtains precise individual cell current measurements through the intermediary busbar structure, avoiding invasive modifications to the cells themselves while maintaining measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The busbar network naturally provides the magnetic field information needed for current measurement as part of its normal current-carrying function. The sensors passively detect the magnetic fields generated by current flow in the busbar links, allowing the busbar structure to 'self-service' the monitoring function without requiring additional active components or invasive cell modifications.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If multiple sensors are used to monitor each cell, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent flow monitoring accuracyVSAvoidsensor array configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each sensor in the array is designed to be universal in its function, measuring current in any busbar link it is positioned against. The sensors share a common design and measurement principle, allowing the system to scale to different battery configurations without requiring different sensor types or complex individual sensor configurations. This universality simplifies the overall device complexity while maintaining precise monitoring capability.

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

Solution Approach 2:

Multiple sensors are merged into a coordinated array system with centralized processing. Rather than treating each sensor as an independent complex unit, the sensors are combined into a unified monitoring system where data from all sensors is processed together to determine individual cell currents. This merging reduces overall system complexity by sharing processing resources and using a unified analysis approach.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If real-time monitoring is implemented, then reliability is improved, but use of energy increases

Engineering Contradiction:
Improvebattery health monitoringVSAvoidsensor power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system replaces active current measurement methods with passive magnetic field detection. Instead of using active sensors that require significant power to measure current directly in the cells, the system uses magnetic field sensors that passively detect the magnetic fields generated by current flow in the busbar links. This substitution dramatically reduces power consumption while maintaining real-time monitoring capability and reliability.

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

Solution Approach 2:

The monitoring approach changes the measurement parameter from direct electrical current measurement to magnetic field strength detection. By measuring the magnetic field parameter instead of directly measuring electrical current, the system achieves real-time monitoring with much lower power consumption, as magnetic field detection requires significantly less energy than active electrical measurement techniques.

Inventive Principle:
Principle #35Parameter changes

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

Provides accurate, real-time monitoring of current flow in battery cells, facilitating early detection of faults, improving battery health assessment, and enabling dynamic reconfiguration to balance load and extend battery life, while being compatible with existing battery modules.

Implementation Method 1

an array of magnetic field sensors, such as fluxgates or optically-pumped magnetometers, positioned on a busbar network to non-invasively measure current flow in each busbar link

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP4025925B1Battery sensor arrangement and method of balancing batteries
Publication Date: 2025.10.22 CDO2 LTD
  • EP4025925B1 patent drawingFigure 1
  • EP4025925B1 patent drawingFigure 2
  • EP4025925B1 patent drawingFigure 3

AI summary

A sensor arrangement for a network of busbar links of a battery module, the sensor arrangement comprising: an array of sensors, each sensor having an output arranged to provide an indication of current in a respective busbar link of the network; a processor coupled to the outputs of the sensors and configured to: receive data from the sensor outputs; process the data to determine a current in each of a set of busbar links that are connected at a node of the network; and compare the currents in the busbar links of the set to determine an overall current at the node.