Battery Charging Equilibrium Method for Voltage Creep

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Solution Overview

Problem

Rechargeable batteries experience voltage creep after charge current removal, leading to reduced charge capacity and unstable voltage, which existing charging methods fail to prevent effectively.

Innovation Solution

A method and device for charging rechargeable batteries that involve supplying a charge current until a battery voltage threshold is reached, pausing, and resuming until a stop charge condition is satisfied, ensuring both capacitors reach equilibrium without voltage creep, thereby maximizing charge capacity without exceeding maximum allowable thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If charge current is supplied continuously until voltage threshold is reached, then charging speed is improved, but voltage creep occurs causing reduced charge capacity

Engineering Contradiction:

Improvecharging speedVSAvoidcharge capacity

Core Design Contradiction:

SpeedVSQuantity of substance

Solution Approach 1:

The charging method employs periodic action by alternating between charge phases and discharge phases. During the charge phase, charge current is supplied to the battery until a first voltage threshold is reached. Then a discharge phase occurs where charge current is removed and the battery voltage creeps down. This periodic charging-discharging cycle allows the battery to reach higher charge capacity (e.g., 4.2V steady state) without permanent voltage creep, as the discharge phase resets the voltage before the next charge phase begins.

Inventive Principle:

Principle #19Periodic action

2Quantity of substance

If charge current is paused frequently to prevent voltage creep, then charge capacity is improved, but charging time increases

Engineering Contradiction:

Improvecharge capacityVSAvoidcharging time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The invention applies partial action by performing discrete, controlled charging intervals rather than continuous charging. The charge current is supplied partially in bursts during charge phases, followed by discharge phases. This partial charging approach prevents excessive voltage accumulation that would lead to permanent creep, while still achieving high charge capacity over multiple cycles. The key is that the partial charging actions are optimized to reach the desired charge level without requiring complete discharge between cycles.

Inventive Principle:

Principle #16Partial or excessive action

3Quantity of substance

If voltage threshold is exceeded to maximize charge capacity, then charge capacity is improved, but battery damage risk increases

Engineering Contradiction:

Improvecharge capacityVSAvoidbattery damage risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention uses preliminary action by proactively removing charge current during discharge phases before voltage creep becomes permanent or damaging. The discharge phase acts as a preventive measure that resets the battery voltage before the next charge phase begins, ensuring that the voltage threshold is not permanently exceeded. This preliminary discharge action prevents the harmful effect of voltage creep accumulation while still allowing the battery to be charged to high capacity levels over multiple cycles.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9048679B2Maximized battery capacity charge based on equilibrium charging

Publication Date: 2015.06.02 MALIKIE INNOVATIONS LTD

AI summary

The present disclosure provides for repeatedly charging a rechargeable battery during a single charging session to a steady state voltage to attain a higher charge capacity of the rechargeable battery than a charge capacity of the rechargeable battery existing prior to the rechargeable battery being charged to the steady state voltage. The higher charge capacity is attained without exceeding a maximum allowable charge threshold of the rechargeable battery.