Cell Balancing Voltage Source for Battery Pack Charging

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Solution Overview

Problem

Existing battery management systems struggle to efficiently and rapidly address cell voltage imbalances in battery packs, leading to reduced discharge capability, limited charge amounts, shortened battery life, and increased maintenance costs due to the inability to individually balance cell voltages during charging and discharging.

Innovation Solution

An apparatus and method that incorporate a cell balancing voltage source within an existing charger, allowing for the rapid and efficient application of a cell balancing voltage to individual cells experiencing imbalance, utilizing a micro-controller unit and switching unit to switch between charging and balancing voltages as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cell balancing scheme uses a resistor to consume cell voltage as heat energy, then cell voltage imbalance is corrected, but energy is wasted and charging time is extended

Engineering Contradiction:
Improvecell voltage balanceVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent introduces an intermediary device (voltage transfer device with capacitor) between the high-voltage cell and low-voltage cell to transfer energy directly. The capacitor acts as a temporary energy storage medium, enabling efficient energy transfer from the high-voltage cell to the low-voltage cell without dissipating energy as heat through a resistor.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of discarding excess voltage energy through resistive dissipation, the patent recovers the energy by transferring it from the high-voltage cell to the low-voltage cell using a capacitor-based voltage transfer mechanism, thereby utilizing the energy that would otherwise be wasted.

Inventive Principle:
Principle #34Discarding and recovering

2Productivity

If cell balancing is performed by a charger providing pack charging voltage, then the battery pack can be charged, but individual cell imbalance cannot be efficiently corrected

Engineering Contradiction:
Improvecharging speedVSAvoidcell voltage balance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the charging function into two independent parts: (1) pack charging voltage source for charging the entire battery pack, and (2) cell balancing voltage source for individually balancing specific cells. This segmentation allows simultaneous or separate operation of pack charging and cell balancing without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The charger is designed with multi-functionality, incorporating both pack charging capability and cell balancing capability. The voltage transfer device can operate in different modes: providing pack charging voltage or providing cell balancing voltage to specific cells, making the charger universally applicable for both functions.

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

3Productivity

If cell voltage imbalance is not corrected, then the battery can operate, but total discharge capability and charge amount are permanently limited

Engineering Contradiction:
Improvebattery performanceVSAvoidbattery capacity utilization
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements preliminary cell balancing action by detecting voltage imbalances and automatically initiating the voltage transfer process before the imbalance severely impacts battery performance. The control device continuously monitors cell voltages and activates the cell balancing function when imbalance is detected, preventing future performance degradation.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If cell balancing is performed using traditional methods, then voltage imbalance is corrected, but the process is time-consuming and reduces charging efficiency

Engineering Contradiction:
Improvecell voltage balanceVSAvoidbalancing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent enables continuous useful action by allowing the cell balancing process to occur simultaneously with pack charging or to quickly complete balancing without interrupting the overall charging process. The voltage transfer device efficiently transfers energy in a continuous manner rather than through intermittent resistive adjustments, significantly reducing balancing time.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3393000B1Charging voltage supply apparatus and supply method
Publication Date: 2021.04.21 LG ENERGY SOLUTION LTD
  • EP3393000B1 patent drawingFigure 1
  • EP3393000B1 patent drawingFigure 2~3

AI summary

The present invention relates to an apparatus and method for providing a charging voltage, and more particularly, to an apparatus and method for providing a charging voltage, which rapidly provide a stable charging voltage to a corresponding cell through a cell balancing voltage source that is one of two separate charging voltage sources, when cell balancing is necessary.