Asymmetric Battery Cell Lines for High Power

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Solution Overview

Problem

Lithium secondary batteries face challenges in simultaneously exhibiting superior high-rate charge and discharge characteristics due to complementary nature of electrode active materials, making it difficult to achieve both high performance and extended calendar life.

Innovation Solution

A battery system with two or more cell lines, each with distinct charge and discharge characteristics, where one line exhibits high-rate charge and the other high-rate discharge, maintaining balance and optimizing charge levels between 30-70% to enhance both charge and discharge performance and extend calendar life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single type of electrode active material is used in the battery system, then the structure is simple and easy to manufacture, but it is difficult to achieve both superior charge characteristic and superior discharge characteristic simultaneously

Engineering Contradiction:
Improveease of manufactureVSAvoidcharge and discharge performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The battery system is divided into multiple battery modules, where each module contains battery cells with different electrode active materials optimized for specific functions (charge vs. discharge). This segmentation allows each module to specialize in one characteristic while the overall system benefits from both characteristics simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different battery modules within the system use different electrode active materials tailored to their specific roles. Modules designated for charging use materials with superior charge characteristics, while modules designated for discharging use materials with superior discharge characteristics, creating local optimization throughout the system.

Inventive Principle:
Principle #3Local quality

2Speed

If battery cells with high-rate charge characteristic are used, then charge performance is improved, but discharge performance deteriorates

Engineering Contradiction:
Improvecharge rateVSAvoiddischarge characteristic
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The battery system segments charge and discharge functions into separate battery modules. Modules with high-rate charge capability are dedicated to charging operations, while modules with high-rate discharge capability are dedicated to discharge operations, eliminating the trade-off present in single-material systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects and activates specific battery modules based on operational requirements. When charging is needed, modules optimized for charge are activated; when discharging is needed, modules optimized for discharge are activated, allowing the system to adapt its characteristics to the current operational mode.

Inventive Principle:
Principle #15Dynamics

3Speed

If battery cells with high-rate discharge characteristic are used, then discharge performance is improved, but charge performance deteriorates

Engineering Contradiction:
Improvedischarge rateVSAvoidcharge characteristic
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The battery system separates discharge-optimized modules from charge-optimized modules. Modules using electrode active materials with superior discharge characteristics are deployed during discharge operations, while modules with superior charge characteristics handle charging, resolving the performance trade-off.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If a single cell line is used in the battery system, then the structure is simple, but it is difficult to achieve both high power and large capacity

Engineering Contradiction:
Improvesystem structureVSAvoidpower and capacity
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The battery system is divided into multiple cell lines with different configurations. Some cell lines are optimized for power delivery with higher discharge rates, while other cell lines are optimized for capacity with higher energy density. The system controller manages these cell lines to achieve both high power and large capacity simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery system uses a composite architecture combining different cell line types. By integrating cell lines with different electrode active materials and configurations, the system achieves a composite performance that delivers both high power and large capacity, surpassing what a single cell line could achieve.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2076929B1High power secondary battery system comprising asymmetric charged cells
Publication Date: 2012.03.14 LG CHEM LTD

AI summary

Disclosed herein is a battery system including two or more kinds of cell lines having different charge and discharge characteristics, wherein each cell line includes one or more battery cells connected in series with each other. In the battery system according to the present invention, the battery cells of at least one cell line exhibit a high-rate charge characteristic, whereas the battery cells of at least another cell line exhibit a high-rate discharge characteristic. Consequently, the high-rate charge and discharge characteristics are improved, and the balance between the charge and discharge characteristics is maintained, whereby the battery system according to the present invention is used as a power source having a high power.