Module Bypass Switch for Battery Pack Inter-Module Balancing

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Solution Overview

Problem

Conventional battery pack systems face challenges in inter-module balancing, leading to safety hazards due to heat generation from resistors in bypass switches and prolonged downtime for balancing new modules, which can take days or weeks, causing operational disruptions.

Innovation Solution

The system incorporates a module bypass switch, charge switch, and discharge switch to allow for rapid inter-module balancing without resistors, reducing heat dissipation and enabling faster balancing by redirecting currents through a low resistance path, and includes current monitoring to optimize charging and discharging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resistor is coupled in series with the bypass switch to prevent short circuiting, then battery cell safety is improved, but heat generation increases causing dangerous conditions

Engineering Contradiction:

Improvebattery cell safetyVSAvoidheat generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the resistor from the bypass circuit entirely. Instead of using a resistor to limit current, the system uses intelligent control of switches to redirect current away from the battery cell during bypass operations, eliminating the heat-generating component while maintaining safety through active current management

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the passive resistive current limiting mechanism with an active electronic control system using switches and control circuitry. This substitution allows for precise control of current paths without the energy dissipation inherent in resistive elements, solving the heat generation problem while maintaining battery protection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-generated harmful factors

If conventional balancing is used without bypass switches, then heat generation is reduced, but balancing time extends to days or weeks causing operational disruptions

Engineering Contradiction:

Improveheat generationVSAvoidbalancing time

Core Design Contradiction:

Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent implements dynamic current management where the bypass switch can be activated temporarily during charging to rapidly equalize voltage between battery cells. This dynamic approach allows high current bypass operations during brief intervals, achieving balance in minutes rather than days, while the overall heat generation remains controlled through selective rather than continuous bypass operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic bypass activation during the charging process. Rather than continuous bypass which would generate excessive heat, the bypass switch is activated in periodic intervals to achieve voltage equalization, then deactivated to allow normal charging to continue, achieving fast balancing with controlled thermal output

Inventive Principle:

Principle #19Periodic action

3Loss of time

If a module bypass switch is used for rapid balancing, then balancing time is reduced, but current monitoring capability is lost

Engineering Contradiction:

Improvebalancing timeVSAvoidbypass current information

Core Design Contradiction:

Loss of timeVSLoss of information

Solution Approach 1:

The patent integrates current monitoring functionality into the existing bypass switch circuitry. The same switch that enables rapid balancing also serves as the sensing element for monitoring bypass current, allowing the system to achieve fast balancing while simultaneously capturing valuable current information for optimization and safety purposes

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution reduces safety hazards, shortens balancing times significantly, and ensures faster module integration by allowing high current inter-module balancing, extending battery life and reducing maintenance costs.

Implementation Method 1

redirecting currents through a low resistance path

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

the resistor 120 consumes power and generates heat in the system 100 through Joule heating

Methodology Applied

Scientific EffectJoule Heating: Joule Heating

Data Source

PatentEP2721716B1Module bypass switch for balancing battery pack system modules with bypass current monitoring

Publication Date: 2017.03.08 SOUTHWEST ELECTRONIC ENERGY CORP

AI summary

A battery pack system module may include a module bypass switch for allowing charge current to bypass the battery pack system module. The module bypass switch may be activated to divert charging current from the battery pack system module to other battery pack system modules. The charging current may be diverted to bring other battery pack system modules into balance with the battery pack system module. That is, to bring the state of charge of all battery pack system modules into coarse balance. When the module bypass switch is activated, charging current through the module bypass switch may be monitored by a current sensing device such as a current sensing resistor. A microprocessor may receive information about the bypass current level and use the information to determine when to de-activate the module bypass switch. Sensing current through a module bypass switch allows more accurate and quicker inter-module balancing.