Decoupling Traction Battery During Auxiliary Charging
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Solution Overview
Problem
In electrified vehicles, when the traction battery is fully charged but the auxiliary battery is depleted, existing systems often draw power from the traction battery to charge the auxiliary battery, leading to inefficiencies and energy wastage, as they fail to isolate the traction battery during auxiliary battery charging.
Innovation Solution
A controller is programmed to decouple the traction battery from the power converter and charger when the traction battery is fully charged and the auxiliary battery voltage falls below a threshold, allowing the auxiliary battery to be charged directly from the charger, thereby isolating the traction battery and optimizing energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traction battery is used to charge the auxiliary battery when the traction battery is fully charged, then the auxiliary battery can be charged, but energy is wasted and charging efficiency is reduced
Solution Approach 1:
The controller checks the charge status of both batteries before initiating charging. When the traction battery is fully charged, the controller preemptively switches the charging source to the external charger, preventing the need to discharge the fully charged traction battery and avoiding energy wastage from circular charging
2Productivity
If the traction battery remains coupled to the power converter during auxiliary battery charging, then power transfer is maintained, but charging efficiency is reduced due to unnecessary power transfer
Solution Approach 1:
The controller extracts the fully charged traction battery from the charging circuit by decoupling it from the power converter. This isolation prevents unnecessary power transfer and energy wastage, while the external charger continues to charge the auxiliary battery independently
3Loss of energy
If the traction battery is isolated from the charger, then energy wastage is reduced, but the system complexity increases
Solution Approach 1:
The controller acts as an intermediary that manages the coupling and decoupling of the traction battery based on charge status. This centralized control logic simplifies the overall system architecture while achieving energy efficiency, as the controller handles all decision-making about battery connections without requiring complex hardware modifications
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 prevents unnecessary discharge of the traction battery, reduces energy wastage, and maximizes charging efficiency by isolating the traction battery during auxiliary battery charging, ensuring both batteries are maintained effectively without wasting energy.
Implementation Method 1
a power converter configured to transfer power from a charger and a traction battery to an auxiliary battery
Data Source
AI summary
A vehicle charging system includes a controller programmed to, in response to a charger being coupled to a power source and parameters being indicative of a low charge level of an auxiliary battery and a full charge level of a traction battery, decouple the traction battery from the power converter and the charger and charge the auxiliary battery from the charger.