Lithium-Rich Pouch Battery Pack Design for High Energy Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion batteries used in electric and plug-in hybrid electric vehicles have limitations in energy density and capacity utilization, with existing cathode materials like LiMn2O4 and LiFePO4 not providing significant improvements in energy density, and existing battery designs facing challenges in achieving high energy output while maintaining compact size and weight.
Innovation Solution
The development of lithium ion pouch battery packs using a lithium rich metal oxide positive electrode active material with a specific composition (Li1+bNiαMnβ−δCoγAδO2−zFz) and a control system, allowing for efficient connection of batteries in series and parallel configurations to achieve high energy capacity and voltage, with each battery having a thickness of 7-18 mm and a planar area of 25,000-50,000 mm², enabling a compact and efficient battery pack design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium ion batteries are designed for high energy density, then energy capacity is improved, but rate performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the cathode particles have a lithium-rich metal oxide core with high capacity and a protective shell layer. This allows the core to provide high energy density while the shell maintains structural integrity and enables faster ion transport, thus achieving both high energy capacity and improved rate performance simultaneously
Solution Approach 2:
The patent uses composite materials by combining lithium-rich metal oxide with other lithium-based cathode materials in a core-shell or composite structure. This composite approach allows the system to leverage the high capacity of lithium-rich materials while the complementary materials provide structural stability and enhanced conductivity, resolving the contradiction between energy density and rate performance
2Volume of moving object
If battery pack size is reduced, then vehicle integration is improved, but energy capacity deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the electrochemical parameters of the cathode materials, achieving energy densities exceeding 900 Wh/L. This allows the battery pack to deliver high energy capacity (40 kWh) in a compact volume, directly resolving the contradiction between small size and high energy capacity
Solution Approach 2:
The use of composite cathode materials with optimized compositions enables higher energy density per unit volume, allowing the battery pack to maintain high energy capacity while reducing overall size for better vehicle integration
3Reliability
If nickel content is reduced, then safety is improved, but energy density deteriorates
Solution Approach 1:
The patent applies local quality by concentrating nickel in specific regions or phases within the cathode structure, such as in the core of core-shell particles or in specific crystallographic sites. This localized nickel placement maintains high energy density while the overall reduced nickel content and protective shell structure improve safety by limiting propagation of thermal runaway
Solution Approach 2:
The patent uses composite materials combining lithium-rich metal oxide with other cathode materials, allowing the system to achieve high energy density through synergistic effects while the diverse material composition inherently improves safety by distributing thermal stress and preventing runaway propagation
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
The solution achieves a high energy density of at least 300 Wh/L and a total capacity of 45 Ah, with a specific energy of 160 Wh/kg, allowing for a compact battery pack design suitable for electric vehicles, providing extended driving ranges and improved cycling performance while reducing weight and size, and offering safety features with reduced nickel content and stable cycling performance.
Implementation Method 1
lithium ion secondary batteries generally have a negative electrode material that intercalates lithium
Data Source
AI summary
High performance battery packs are described especially for use in electric vehicles and plug-in hybrid electric vehicles. Based on high energy lithium ion battery designs, the battery packs can have pairs of parallel connected batteries to supply an energy capacity at full discharge of at least about 40 kilowatt-hours or in alternative embodiments a set of all series connected batteries that can produce at full discharge at least about 15 kilowatt-hours. In some embodiments, lithium rich positive electrode active materials can be used to form the batteries in which the material comprises a composition approximately represented by a formula xLi2M′O3. (1−x)LiMO2 with x from about 0.05 to about 0.8.