Passive Battery Module CAN Bus Powering

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Solution Overview

Problem

Modern rechargeable batteries without integrated electronics, such as lead-acid batteries, cannot be identified by intelligent chargers, preventing intelligent charging management and requiring additional power sources for passive add-on modules, which complicates installation and increases costs.

Innovation Solution

A passive add-on module for rechargeable batteries that uses a CAN transceiver, control device, voltage supply circuit, and energy storage device to communicate with CAN bus-compatible chargers, charging during communication pauses via voltage differences in the CAN bus data lines, eliminating the need for a separate power source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passive add-on module is equipped with its own independent power supply (battery), then it can operate independently and store data, but manufacturing costs and maintenance effort increase

Engineering Contradiction:
Improveoperational reliabilityVSAvoidmanufacturing costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The CAN bus data lines are made to serve dual functions: both data communication and power supply for the passive add-on module. The voltage differences between CAN bus lines (CAN_H to GND, CAN_L to GND, or CAN_H to CAN_L) are utilized to charge the energy storage device, eliminating the need for separate power lines and reducing overall system complexity.

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

Solution Approach 2:

The passive add-on module charges its own energy storage device using the power available from the CAN bus communication lines themselves. During communication pauses, the module extracts energy from the voltage differences in the CAN bus lines to maintain operation without requiring external power intervention.

Inventive Principle:
Principle #25Self-service

2Use of energy by moving object

If power is supplied via the battery's connections or connecting cables, then the module has power, but operational reliability is compromised and additional technical effort is required

Engineering Contradiction:
Improvepower supplyVSAvoidoperational reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The passive add-on module acts as an intermediary that draws power from the CAN bus communication infrastructure rather than directly from the battery connections. This isolation prevents potential interference with battery operations while still providing necessary power to the module.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If intelligent charging management is implemented for passive batteries, then charging efficiency improves, but device complexity increases due to additional electronics

Engineering Contradiction:
Improvecharging efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The passive add-on module uses a simple energy storage device (capacitor or small battery) with minimal electronics, accepting that it may need replacement rather than designing for long-term durability. This approach keeps costs low and complexity minimal while still enabling intelligent charging functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The intelligent charging management functionality is extracted from the battery itself and placed in the passive add-on module. This allows the battery to remain simple and unchanged while the add-on module handles all communication and charging management tasks.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If retrofitting is performed without interventions in battery connections, then cost-effectiveness improves, but ensuring operational reliability becomes more difficult

Engineering Contradiction:
Improvecost-effectivenessVSAvoidoperational reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The system is segmented into the existing battery and the separate passive add-on module. The add-on module connects to the battery through the existing charging plug infrastructure rather than requiring direct battery terminal connections, simplifying installation while maintaining reliability through proper electrical isolation and connection protocols.

Inventive Principle:
Principle #1Segmentation

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

Enables intelligent charging management for batteries without integrated electronics, reducing manufacturing and maintenance costs while ensuring operational reliability and ease of retrofitting, without compromising performance.

Implementation Method 1

the charging circuit (5) is designed to charge the energy storage device (9), at least during communication pauses, via the voltage difference between a CAN-bus data line and the reference potential or between both CAN-bus data lines

Methodology Applied
Scientific EffectVoltage difference: Electric Field

Data Source

PatentEP4046255B1Passive additional module for a battery, battery comprising such an additional module and method for supplying power to a passive additional module
Publication Date: 2025.07.30 FRONIUS INT GMBH
  • EP4046255B1 patent drawingFigure 1~3
  • EP4046255B1 patent drawingFigure 4
  • EP4046255B1 patent drawingFigure 5~6

AI summary

The invention relates to a passive supplementary module (1) for rechargeable batteries (2), comprising connections (3, 3') for connection to at least two CAN bus data lines (CANH, CANL) of a CAN bus-compatible charging device (6), relates to a rechargeable battery (2) comprising such a passive supplementary module (1) and relates to a method for supplying energy to such a passive supplementary module (1). In order to create a passive supplementary module (1) by way of which a rechargeable battery (2) can be identified, a CAN transceiver (4) which is connected to the connections (3, 3'), a control device (8) which is connected to the CAN transceiver (4), a voltage supply circuit (7) for providing a supply voltage (Vb) with respect to a reference potential (GND), an energy store (9) and a data memory (10) which is connected to the control device (8) are provided, and the voltage supply circuit (7) is connected to a charging circuit (5) via the energy store (9), and the charging circuit (5) is connected to the control device (8) and is designed to charge the energy store (9) by way of the CAN bus-compatible charging device (6) at least in the intervals in communication about the voltage difference between a CAN bus data line (CANH, CANL) and the reference potential (GND) or between two CAN bus data lines (CANH, CANL).