E-Bike Battery Switching to Block Reverse Current During Handover
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Solution Overview
Problem
In electric bicycles equipped with two batteries, switching from a higher output battery to a lower output battery can cause a temporary increase in the electric potential of the drive unit, leading to an electrical current flowing from the drive unit to the battery, which may harm the battery's operation.
Innovation Solution
The electric bicycle incorporates a battery switching device with a control system that manages two electricity control switches. The second switch has a bidirectional conduction state, an intermediate state, and a bidirectional inhibition state, allowing the control device to prevent current flow from the drive unit to the battery by setting the switch to the intermediate or inhibition state based on the electric potential comparison between the drive unit and the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the battery is switched from high output electric potential to low output electric potential, then the battery can supply electrical power to the drive unit, but the electric potential of the drive unit temporarily becomes higher than the battery, causing electrical current to flow from the drive unit to the battery which may harm battery operation
Solution Approach 1:
The control device sets the second electricity control switch to the intermediate state before battery switching occurs. This preliminary action prepares the switch to allow current from the second battery to the drive unit while blocking reverse current from the drive unit to the battery, preventing the harmful effect before it can occur.
Solution Approach 2:
The second electricity control switch acts as an intermediary between the second battery and the drive unit. By introducing this switching device with three states (bidirectional conduction, intermediate, and bidirectional inhibition), the system can control current flow direction and prevent harmful reverse current while maintaining normal power supply functionality.
2Loss of energy
If the second electricity control switch is set to bidirectional conduction state to allow current flow, then the battery can be charged from the drive unit during regenerative braking, but electrical current may flow from the drive unit to the battery when electric potential of drive unit exceeds battery potential
Solution Approach 1:
The second electricity control switch dynamically transitions between three states based on operating conditions: bidirectional conduction state for normal charging, intermediate state during battery switching to prevent reverse current, and bidirectional inhibition state when needed. This dynamic adaptation allows the system to recover energy when safe while protecting the battery when vulnerable.
Solution Approach 2:
The control device changes the conduction parameters of the second electricity control switch based on the comparative relationship between drive unit electric potential and battery electric potential. When the drive unit potential exceeds battery potential, the switch is set to intermediate state to block reverse current; otherwise, bidirectional conduction is allowed for energy recovery.
3Device complexity
If a simple switching mechanism is used to reduce device complexity, then the battery switching function can be achieved, but the system cannot prevent reverse current flow from drive unit to battery
Solution Approach 1:
The second electricity control switch is designed with multi-functionality, serving as a bidirectional switch that can operate in three distinct states: allowing bidirectional current flow for energy recovery, blocking reverse current during battery switching, and providing complete bidirectional inhibition when needed. This universal component handles multiple functions that would otherwise require separate devices.
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 prevents electrical current from flowing from the drive unit to the battery during switching, thereby protecting the battery's operation and extending its lifespan.
Implementation Method 1
The bidirectional conduction state allows both of an electrical current flowing from the second battery to the drive unit and an electrical current flowing from the drive unit to the second battery
Data Source
AI summary
A control device sets a second electricity control switch in an intermediate state in a process of switching a discharge battery for supplying a drive unit with an electrical current from a first battery to a second battery. Subsequently, when a comparative relationship between an electric potential of a smoothing capacitor and an electric potential of the second battery fulfills an intermediate state termination condition, the control device sets the second electricity control switch in a bidirectional conduction state. The intermediate state is when an electrical current flowing from the second battery to the drive unit is allowed, and an electrical current flowing from the drive unit to the second battery is inhibited. The bidirectional conduction state is when both of the electrical current flowing from the second battery to the drive unit and the electrical current flowing from the drive unit to the second battery are allowed.