Li-Ion Battery Pack Voltage Balancing via Supervision Feedback

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Solution Overview

Problem

Hybrid vehicles using battery packs formed by serially-connected battery cells face issues due to random differences in working parameters such as internal resistances and chemical material non-homogeneities, leading to operational inefficiencies and potential overheating or voltage imbalances, which can prevent proper operation of the vehicle.

Innovation Solution

A battery management system that includes a supervision unit and activating circuit to monitor and adjust the operation conditions of the battery pack by sampling voltages, temperatures, and currents, and generating control signals to balance voltages and disconnect the battery pack when critical thresholds are exceeded, ensuring proper operation and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If battery cells are serially connected to form a battery pack, then the voltage is increased to meet hybrid vehicle power requirements, but random differences in working parameters among cells lead to voltage imbalances and operational inefficiencies

Engineering Contradiction:
ImprovevoltageVSAvoidvoltage balance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements a battery management system with supervision unit that continuously monitors voltage, temperature, and current of each battery cell. The system uses feedback control to detect voltage imbalances and activate balancing circuits that transfer charge between cells, ensuring voltage equilibrium while maintaining the high voltage output required for hybrid vehicle operation.

Inventive Principle:
Principle #23Feedback

2Power

If battery cells are closely packed to increase energy density, then the power output is improved, but thermal distribution becomes non-uniform causing overheating and reduced reliability

Engineering Contradiction:
Improvepower outputVSAvoidthermal distribution
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent incorporates temperature sensors at multiple locations within the battery pack to detect local thermal conditions. The supervision unit processes this spatially-resolved temperature data and activates cooling mechanisms or adjusts cell connections based on local thermal states, enabling differentiated thermal management that maintains high power density while preventing overheating in specific regions.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If a conventional battery pack structure is used, then manufacturing is simplified, but assembly and disassembly are difficult and time-consuming

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidassembly and disassembly
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent divides the battery pack into modular units with standardized interfaces. Each module contains a subset of battery cells with integrated management circuits and connection terminals. This segmentation allows individual modules to be independently assembled, tested, and replaced, significantly reducing assembly time and facilitating maintenance while maintaining manufacturing efficiency through standardized production processes.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3216078B1Modular design of a 48-volt li-ion battery for ease of assembly and disassembly
Publication Date: 2021.07.21 CPS TECHNOLOGY HOLDINGS LLC
  • EP3216078B1 patent drawingFigure 1A
  • EP3216078B1 patent drawingFigure 1B
  • EP3216078B1 patent drawingFigure 1C

AI summary

The present invention provides a battery that includes a plurality of serially connected battery cells. The battery includes an upper housing and a lower housing. The battery comprises : a wire harness assembly; a middle housing that includes a plurality of cell chambers for accommodating the top sections of the plurality of serially connected battery cells. The lower housing includes a plurality of cell chambers for accommodating the bottom sections of the plurality of serially connected battery cells 102; and the middle housing has a top surface for installing the wire harness assembly (1106) and the plurality of cell chambers beneath the top surface (1102) of the middle housing.