Modular E-Bike Battery Pack With Releasable Series Booster
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Solution Overview
Problem
Electric assist bicycles are often equipped with heavy and expensive batteries that are not efficiently utilized for shorter rides, as secondary cell stacks connected in parallel do not increase the total voltage, leading to unnecessary energy expenditure and limited range extension.
Innovation Solution
A battery system comprising a main battery with a charge controller and an auxiliary battery, where the auxiliary battery is releasably coupled in series to the main battery, increasing the total output voltage and capacity, and can be decoupled for storage or replaced with a storage container for shorter rides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a heavy and expensive battery is used to extend range, then the battery capacity is increased, but the weight and energy expenditure for shorter rides increases unnecessarily
Solution Approach 1:
The battery system is divided into a main battery and a secondary battery that can be used independently or combined. The main battery is permanently installed and provides power for short rides, while the secondary battery can be added for longer rides to extend range without carrying it for every ride.
Solution Approach 2:
The battery configuration is made dynamic and adaptable to different ride requirements. The system can switch between using only the main battery for short rides, or combine both batteries for longer rides, allowing the rider to optimize weight vs. capacity based on specific trip needs.
2Quantity of substance
If secondary and primary cell stacks are connected in parallel, then the battery capacity is extended, but the total voltage of the system does not increase
Solution Approach 1:
The system changes the electrical configuration parameter from parallel connection to series connection when both batteries are used. This parameter change transforms the electrical output, doubling the voltage when both main and secondary batteries are connected in series, thereby increasing power delivery capability along with capacity.
3Power
If the auxiliary battery is releasably coupled in series, then the total output voltage and capacity are increased, but the system complexity increases
Solution Approach 1:
The secondary battery unit is designed with multi-functionality: it can be used as a power source when attached to the main battery, and it can also serve as a storage container when not needed for power extension. This universal design reduces system complexity by eliminating the need for separate storage solutions.
4Duration of action of moving object
If a larger battery is used to provide additional capacity, then the range is extended, but the energy expenditure for transporting the battery increases
Solution Approach 1:
The battery system is segmented into essential (main battery) and optional (secondary battery) components. For short rides, only the lighter main battery is used, minimizing energy expenditure. For longer rides, the secondary battery is added to extend range, accepting the additional energy cost only when necessary.
Data Source
AI summary
A battery system includes an auxiliary battery releasably coupled to a main battery. The main battery includes a charge controller and has a first output voltage. The main battery is configured to be electrically coupled to a bicycle drive unit and supply power to the drive unit. The auxiliary battery has a second output voltage. The auxiliary battery is releasably coupled to the main battery in series such that a total output voltage of the main battery and auxiliary battery is equal to a sum of the first and second output voltages.