Prelithiated Anode Composite Cathode Lithium Ion Battery Formation Loss

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium ion batteries face significant formation loss during the first charging cycle, leading to reduced specific energy and increased demand for costly and toxic metals like cobalt and nickel, due to the need for overdimensioning of cathode active materials and complex production processes.

Innovation Solution

A lithium ion battery design featuring a composite cathode active material with a first material at a higher degree of lithiation and a second material with an olivine structure at a lower degree of lithiation, combined with a prelithiated anode, allowing lithium ions to be incorporated into the second cathode during discharging and reducing formation losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cathode active material is overdimensioned to compensate for formation loss, then formation loss is compensated, but specific energy decreases and production costs increase

Engineering Contradiction:

Improveformation loss compensationVSAvoidspecific energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The anode is prelithiated before battery assembly by contacting it with a lithium source (such as lithium foil or lithium-containing powder) to introduce additional lithium ions. This preliminary action ensures that sufficient lithium is available during formation to create the SEI layer without requiring overdimensioning of the cathode, thereby maintaining high specific energy while compensating for formation loss.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If cathode active material is overdimensioned to compensate for formation loss, then formation loss is compensated, but production costs increase

Engineering Contradiction:

Improveformation loss compensationVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

3Reliability

If additional lithium depot is provided to compensate lithium losses, then lithium loss compensation is achieved, but cell construction complexity increases

Engineering Contradiction:

Improvelithium loss compensationVSAvoidcell construction complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lithium compensation function is merged with the anode structure itself through prelithiation. Instead of adding a separate lithium depot component, lithium is directly introduced into the anode (e.g., by coating lithium foil onto the anode or mixing lithium-containing powder with the anode material), integrating the compensation mechanism into the existing anode design and avoiding increased construction complexity.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If formation process is performed with exacting safety standards, then safety is ensured, but production time and costs increase

Engineering Contradiction:

ImprovesafetyVSAvoidproduction efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The anode is prelithiated before battery assembly, which ensures that sufficient lithium is available for SEI formation during the first charge cycle. This preliminary preparation reduces the risks associated with formation (such as dendrite formation or insufficient SEI coverage) while enabling more efficient formation processes, thereby improving production efficiency without compromising safety.

Inventive Principle:

Principle #10Preliminary action

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 approach enhances the specific energy and current-carrying capacity of lithium ion batteries, reduces the need for expensive cathode active materials, simplifies production, and eliminates the need for a precharge step, thereby lowering production costs and time.

Implementation Method 1

the lithium ions depart the cathode and are intercalated in the anode

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

The formation of the SEI, which is also regarded as a protective layer, is attributed substantially to decomposition reactions of the electrolyte with the surface of the anode active material

Methodology Applied

Scientific EffectSolid electrolyte interface formation: Decomposition (biological)

Implementation Method 3

both the cathode active material and the anode active material must be capable of reversibly receiving and releasing lithium ions

Methodology Applied

Scientific EffectReversible lithium ion intercalation: Absorption (physical)

Data Source

PatentUS20230016431A1Lithium Ion Battery and Method for Producing a Lithium Ion Battery

Publication Date: 2023.01.19 BAYERISCHE MOTOREN WERKE AG

AI summary

A lithium ion battery includes a cathode, which has a composite cathode active material, and an anode, which has an anode active material. The composite cathode active material includes at least a first and a second cathode active material, wherein the second cathode active material is a compound having an olivine structure, and wherein at least a lithiation degree of the first cathode active material differs from a lithiation degree of the second cathode active material. Prior to electrolyte filling or the first discharging and/or charging process of the lithium ion battery, the lithiation degree of the first cathode active material is higher than the lithiation degree of the second cathode active material. Prior to electrolyte filling or the first discharging and/or charging process of the lithium ion battery, the anode active material is pre-lithiated. A method for producing a lithium ion battery of this kind is also described.