Automotive Battery Pack Segmentation for On-Board Network Power

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Solution Overview

Problem

Lead-acid batteries used in electric and hybrid vehicles are inefficient due to limited usable energy, high mass, bulkiness, and difficulty in determining state of charge, requiring frequent replacement and additional power components like DC/DC converters.

Innovation Solution

A battery pack with two groups of cells, where one group supplies the electric motor and another group directly supplies the on-board network without an intermediate converter, allowing for separate charging and operation, reducing mass and installation complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a lead-acid battery is used to power the on-board network, then the battery can provide sufficient energy capacity, but the mass increases significantly and the battery becomes bulky

Engineering Contradiction:
Improveenergy capacityVSAvoidbattery mass
Core Design Contradiction:
Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The battery pack is segmented into two distinct groups: a first group of cells for powering the electric motor and a second group of at least one cell for powering the on-board network. This segmentation allows each group to be optimized for its specific function, with the second group sized appropriately for on-board power needs rather than requiring a large lead-acid battery for the entire system.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a lead-acid battery is used to power the on-board network, then the battery can maintain sufficient charge, but the device complexity increases due to required DC/DC converters and voltage regulation components

Engineering Contradiction:
Improvebattery functionVSAvoidpower conversion components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the on-board network power function from the traction battery system by providing a dedicated second group of cells. This eliminates the need for DC/DC converters and intermediate voltage conversion stages, as the second group directly powers the on-board network at the appropriate voltage level.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If a lead-acid battery is used, then the battery can provide adequate power output, but the state of charge is difficult to determine and the battery requires frequent replacement

Engineering Contradiction:
Improvepower outputVSAvoidstate of charge
Core Design Contradiction:
PowerVSDifficulty of detecting and measuring

Solution Approach 1:

The invention applies local quality by using lithium-ion cells with advanced state-of-charge monitoring capabilities in the second group, which are easier to measure and manage than lead-acid batteries. The control system can precisely monitor the state of charge of individual cells in the second group, enabling accurate determination without the difficulties associated with lead-acid battery measurement.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If a standard rectangular battery casing is used, then the battery can be manufactured with standard dimensions, but the installation difficulty increases due to space constraints

Engineering Contradiction:
Improvestandard casingVSAvoidinstallation
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The battery pack is divided into two separate groups of cells that can be independently configured and installed. The second group, dedicated to on-board network power, can be positioned in optimal locations within the vehicle based on space availability and electrical connection requirements, rather than being constrained by a single large rectangular casing.

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

This configuration enhances energy efficiency, reduces mass and cost, simplifies installation, and eliminates the need for frequent battery replacements and high-power converters, while improving power availability and safety by isolating the traction network from the chassis.

Implementation Method 1

a battery pack for a motor vehicle equipped with an electric traction motor and an on-board electrical system, comprising a set of cells

Methodology Applied
Scientific EffectElectrochemical energy storage and conversion: Battery (electricity)

Data Source

PatentEP3224923B1Battery pack for an automotive vehicle
Publication Date: 2020.09.09 RENAULT SA
  • EP3224923B1 patent drawingFigure 1~2
  • EP3224923B1 patent drawingFigure 3~4
  • EP3224923B1 patent drawingFigure 5

AI summary

Battery pack for an automotive vehicle equipped with an electric traction motor and with an onboard electric network (R2), comprising a set of cells (C1 to CN) which comprises a first group of cells (G1) intended to supply the electric motor and a second group (G2) of at least one cell, adapted to supply the onboard network of the vehicle.