Battery Adapter Circuit for Ni-Cd Charger Compatibility

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Solution Overview

Problem

Existing chargers for nickel-cadmium (Ni-Cd) batteries cannot safely charge lithium-ion (Li-Ion) batteries due to differences in end-of-charge voltage and overcharging tolerance, rendering direct substitution and charging impractical.

Innovation Solution

An adapter circuitry is developed that mimics the electrical characteristics of Ni-Cd batteries to enable safe charging of Li-Ion batteries using Ni-Cd battery chargers, incorporating a battery voltage detector and protector to prevent overcharging, and a pulsing circuit to manage charging indicators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Li-Ion batteries are charged using Ni-Cd battery chargers, then charging compatibility is improved, but battery safety deteriorates due to overcharging risks

Engineering Contradiction:
Improvecharging compatibilityVSAvoidbattery safety
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an adapter circuit as an intermediary device between the Li-Ion battery and the Ni-Cd charger. This adapter mimics the electrical characteristics of a Ni-Cd battery, allowing the charger to operate safely while actually charging the Li-Ion battery. The adapter mediates the incompatible charging parameters (voltage, current profile) between the two different battery systems, resolving the safety concern while maintaining charging compatibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adapter circuit dynamically changes electrical parameters during the charging process. It monitors the Li-Ion battery voltage and adjusts the charging current accordingly, transitioning from constant current charging to constant voltage charging as the battery approaches full charge. This parameter adjustment prevents overcharging while maintaining compatibility with the Ni-Cd charger's expected electrical characteristics.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If different battery types are used in existing devices, then performance and environmental safety are improved, but device compatibility deteriorates

Engineering Contradiction:
Improveenvironmental safetyVSAvoiddevice compatibility
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The adapter creates an electrical copy or simulation of a Ni-Cd battery's charging characteristics. By replicating the voltage profile, current response, and electrical behavior of a Ni-Cd battery, the adapter allows Li-Ion batteries (which are environmentally safer) to be used in devices designed for Ni-Cd batteries. This copying approach maintains device compatibility while enabling the use of superior battery technology.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The adapter serves multiple functions: it acts as an electrical interface, a parameter converter, a safety protector, and a communication bridge between the charger and battery. This multi-functionality allows a single adapter design to work with various Li-Ion batteries in different devices, providing universal compatibility while enabling the transition from Ni-Cd to Li-Ion battery technology.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If standard charging methods are used for Li-Ion batteries, then charging speed is improved, but charging infrastructure compatibility deteriorates

Engineering Contradiction:
Improvecharging speedVSAvoidcharger compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The adapter implements dynamic charging control by continuously monitoring battery voltage and adjusting charging parameters in real-time. It transitions the charging regime from the static constant-current method expected by Ni-Cd chargers to the dynamic constant-voltage method required by Li-Ion batteries. This dynamic adaptation maintains compatibility with existing chargers while enabling safe and efficient Li-Ion charging.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2422425B1Rechargeable flashlight, battery and charger adapter and protector therefor
Publication Date: 2019.10.23 STREAMLIGHT INC
  • EP2422425B1 patent drawingFigure 1A
  • EP2422425B1 patent drawingFigure 1B
  • EP2422425B1 patent drawingFigure 2

AI summary

An adapter (100, 100') for replacing an original battery, light or battery powered device utilizing a battery of a first type with a replacement battery (150), light (10, 10') or battery powered device (10, 10') utilizing a battery (150) of a second and different type may comprise first terminals (120, 122, 124, 58) configured similarly to terminals of an original battery, light or battery powered device, second terminals (58, 202, 204) for connecting to a replacement battery (150), light (10, 10'), or battery powered device (10, 10'), and an electronic circuit (200, 300, 300') for controlling charging of the replacement battery (150), light (10, 10'), or battery powered device (10, 10') connected to the second terminals (58, 202, 204) when a battery charging device (400) for a battery of the first type is connected to the first terminals (120, 122, 124, 58).