Solid Battery Overdischarge Recovery for Internal Resistance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Solid secondary batteries experience deterioration in output characteristics due to repeated charge and discharge cycles, leading to increased internal resistance, which is difficult to recover, especially when stored at high temperatures.

Innovation Solution

Incorporating an overdischarge processing unit that intentionally discharges the battery until a state of charge less than 0% or specific cathode potential is reached, reducing internal resistance and recovering output characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If solid secondary batteries undergo repeated charge and discharge cycles, then battery capacity is maintained, but internal resistance increases and output characteristics deteriorate

Engineering Contradiction:

Improvebattery cycle lifeVSAvoidoutput characteristics

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by performing overdischarge processing before the battery is fully degraded. By intentionally discharging the battery to a state of charge below 0% (negative SOC) at predetermined intervals, the high-resistive membranes forming at the electrode-s electrolyte interfaces are removed before they cause significant performance degradation, thus maintaining output characteristics throughout the battery's operational life

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of overdischarge (which traditionally damages batteries) into a beneficial process. By intentionally applying overdischarge conditions, the high-resistive membranes that normally form during aging are removed, reducing internal resistance and improving output characteristics. This transforms what was previously considered a destructive process into a restorative maintenance method

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Stability of the object's composition

If solid secondary batteries are stored at high temperature, then storage stability is improved, but internal resistance increases and output characteristics deteriorate

Engineering Contradiction:

Improvestorage stabilityVSAvoidoutput characteristics

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies the blessing in disguise principle by using high-temperature storage conditions to accelerate the formation of high-resistive membranes, then removing them through overdischarge processing. The high temperature speeds up the membrane formation process, making it easier to detect and remove these membranes through controlled overdischarge, thereby restoring output characteristics without compromising long-term storage stability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If conventional overdischarge protection means is implemented, then battery safety is improved, but ability to recover output characteristics is lost

Engineering Contradiction:

Improvebattery safetyVSAvoidrecovery capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies segmentation by separating the battery management functions into two distinct modes: normal operation mode with overdischarge protection to ensure safety, and maintenance mode with controlled overdischarge to recover output characteristics. The control unit switches between these modes based on battery state, allowing both safety and performance recovery to be achieved without conflict

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic action by performing overdischarge processing at predetermined intervals rather than continuously. The control unit monitors battery state and applies controlled overdischarge only when needed for maintenance, alternating between normal protected operation and recovery processing. This periodic approach enables the battery to maintain both safety through protection during normal use and performance through periodic recovery treatments

Inventive Principle:

Principle #19Periodic 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

The overdischarge processing unit effectively reduces internal resistance and extends the lifetime of solid secondary batteries by removing high-resistive membranes at interfaces, thereby recovering degraded output characteristics.

Implementation Method 1

a solid electrolyte layer formed between the cathode active material layer and the anode active material layer

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

an overdischarge processing unit that discharges the at least one solid secondary battery until a state of charge of the at least one solid secondary battery becomes less than 0%

Methodology Applied

Scientific EffectElectrochemical reaction: Redox Reactions

Data Source

PatentUS9893386B2Solid secondary battery system and manufacturing method of recoverable solid secondary battery

Publication Date: 2018.02.13 TOYOTA JIDOSHA KK

AI summary

The invention provides a solid secondary battery system including a solid secondary battery having a cathode active material layer, an anode active material layer, and a solid electrolyte layer formed between the cathode active material layer and the anode active material layer, and an overdischarge processing unit for discharging the solid secondary battery until a SOC of the solid secondary battery becomes less than 0%.