Battery Balancing Circuit Heating via Joule Effect

Solution Overview

Problem

Existing battery pack systems face challenges in maintaining cell temperatures above a minimum threshold without increasing weight or cost, especially at low ambient temperatures, as methods like increasing cell count or adding heating elements lead to inefficiencies and higher costs.

Innovation Solution

Incorporating a battery management system (BMS) with heat dissipating resistors and a charger directly coupled to balancing circuits, which monitors temperature and activates current flow through the resistors to maintain cell temperatures above a threshold without discharging the battery cells, thus preserving their life and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heating elements are added to maintain battery cell temperature, then temperature control is improved, but device complexity and cost increase

Engineering Contradiction:

Improvebattery cell temperatureVSAvoidsystem complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The balancing circuit is made multi-functional by enabling it to perform both its traditional cell balancing function and a heating function. The same balancing circuitry that equalizes charge across cells is repurposed to generate heat for warming cells in cold conditions, eliminating the need for separate heating elements and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Temperature

If heating elements are added to maintain battery cell temperature, then temperature control is improved, but weight increases

Engineering Contradiction:

Improvebattery cell temperatureVSAvoidbattery pack weight

Core Design Contradiction:

TemperatureVSWeight of moving object

Solution Approach 1:

The balancing circuit is made multi-functional by enabling it to perform both its traditional cell balancing function and a heating function. The same balancing circuitry that equalizes charge across cells is repurposed to generate heat for warming cells in cold conditions, eliminating the need for separate heating elements and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The balancing circuit generates its own heat as a byproduct of its operation, which is then utilized to warm the battery cells. This self-service approach means the system uses its existing components to provide the heating function without requiring external power sources or additional heating hardware, thereby avoiding weight penalties.

Inventive Principle:

Principle #25Self-service

3Temperature

If cell count is increased to maintain temperature, then temperature maintenance is improved, but cost and weight increase

Engineering Contradiction:

Improvebattery cell temperatureVSAvoidnumber of battery cells

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The balancing circuit generates its own heat as a byproduct of its operation, which is then utilized to warm the battery cells. This self-service approach means the system uses its existing components to provide the heating function without requiring external power sources or additional heating hardware, thereby avoiding weight penalties.

Inventive Principle:

Principle #25Self-service

4Temperature

If balancing circuit current is increased for heating, then temperature control is improved, but energy loss increases

Engineering Contradiction:

Improvebattery cell temperatureVSAvoidenergy dissipation

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The resistive heating that traditionally represents energy loss and inefficiency in the balancing circuit is converted into a beneficial heating source. Instead of dissipating heat wastefully, the system captures and utilizes this thermal energy to warm the battery cells, transforming an energy loss into a useful function that improves overall system efficiency.

Inventive Principle:

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

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 effectively maintains battery cell temperatures within a desired range without significant weight or cost increases, ensuring optimal performance and extending battery life by using existing BMS components and preventing cell discharge.

Implementation Method 1

charging, by a current directly from a charger, a balancing circuit including a resistor in proximity to the cell... sending a current, directly from a charger, to a balancing circuit coupled to the cell to dissipate heat from a resistor

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11145917B2Cell balancing network to heat battery pack

Publication Date: 2021.10.12 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A method for increasing temperature of a battery pack includes determining whether a temperature of a cell in the battery pack is above a lower threshold temperature. The method further includes charging, by a current directly from a charger, a balancing circuit including a resistor in proximity to the cell. The method also includes increasing the temperature of the cell in the battery pack.