Redox Shuttle Battery Charge Control for Power Tools
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Solution Overview
Problem
Lithium-based rechargeable batteries in power tools are prone to rapid deterioration due to overcharging, over-discharging, and overheating, necessitating extensive protective measures that increase product costs.
Innovation Solution
A simplified charge control scheme for power tools using lithium-ion battery cells with a microcontroller powered by an AC adapter, which monitors voltage and terminates charging, combined with a redox shuttle material in the electrolyte, reducing the need for expensive charge and discharge controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extensive protective measures are employed to prevent overcharging, over-discharging, and overheating of lithium battery cells, then battery safety and reliability are improved, but product cost significantly increases
Solution Approach 1:
The redox shuttle material enables the battery cell to automatically regulate its own charging process. When the battery reaches full charge, the redox shuttle material physically blocks further lithium ion insertion, causing the charging current to automatically cease without requiring external control circuits. This self-regulating mechanism eliminates the need for complex protective electronics while maintaining battery safety.
Solution Approach 2:
The patent extracts the protective function from external control circuits and embeds it directly into the battery cell's electrolyte through the redox shuttle material. By moving the protection mechanism from the system level (external controllers) to the component level (internal electrolyte), the patent eliminates expensive protective circuits while retaining safety functionality.
2Reliability
If complex charge and discharge control circuits are used to protect lithium battery cells, then battery deterioration is prevented, but device complexity increases
Solution Approach 1:
The redox shuttle material provides autonomous protection against overcharging and overheating without requiring external monitoring or control systems. The material's inherent chemical properties enable it to automatically stop charging at full capacity and prevent thermal runaway, eliminating the need for microcontrollers, voltage sensors, and temperature sensors.
Solution Approach 2:
The patent replaces electronic control systems with a chemical mechanism. Instead of using electronic sensors and control circuits to monitor and regulate charging, the system uses the redox shuttle material's chemical behavior to automatically regulate ion flow based on the battery's charge state.
3Reliability
If multiple protective measures are implemented for lithium battery cells, then battery performance under adverse conditions is improved, but manufacturing cost increases
Solution Approach 1:
The patent incorporates redox shuttle materials into the battery's electrolyte composition to create a composite system with inherent protective properties. This single material addition provides multiple protective functions simultaneously, including overcharge protection, thermal runaway prevention, and cycle life extension, replacing the need for multiple separate protective components.
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 solution effectively reduces the cost of power tools by eliminating the need for expensive protective measures while ensuring safe and efficient charging of lithium-ion battery cells, thereby enhancing the tool's operational reliability and reducing the risk of battery deterioration.
Implementation Method 1
each of the battery cells preferably employs an electrolyte composition comprised of a redox shuttle material
Data Source
AI summary
A simplified control scheme is presented for use in a power tool. The power tool may be comprised of two or more lithium-ion battery cells connected in series and operable to drive the motor in the tool. A charging circuit is configured to receive a charging current from an AC adapter and to supply the charging current to the battery cells. A microcontroller monitors the voltage of the battery cells and terminates charging of the battery cells in accordance with the monitored voltages of the battery cells. The microcontroller does not receive power from the battery cells but is only powered by the AC adapter. Of note, each of the battery cells preferably employs an electrolyte composition comprised of a redox shuttle material. In combination with other tool components, the use of the redox shuttle material reduces or eliminates the need for expensive charge and discharge controls, thereby reducing the cost of the tool.