EV Battery Pack Series Charging With DC-DC Charge Balancing
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Solution Overview
Problem
Existing recharge stations capable of delivering high voltages like 800 V are expensive, and existing batteries and components to support these voltages are costly, limiting the widespread use of high-power recharge stations.
Innovation Solution
A power-supply and recharge circuit for electric vehicles that connects two battery packs in series, using DC-to-DC converters to balance charge between them and enable efficient use of high-power recharge stations with standard, lower-voltage batteries and components, allowing for voltage adjustment and charge balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power recharge stations delivering 800 V are used, then charging speed and power are improved, but battery and component cost increase significantly
Solution Approach 1:
The battery system is divided into multiple battery packs (first battery pack and second battery pack) that can be connected in series during recharging. This segmentation allows the system to interface with high-voltage recharge stations while each individual battery pack can use standard, lower-voltage components, reducing overall cost.
Solution Approach 2:
A DC-to-DC converter is introduced as an intermediary device between the recharge station and the battery packs. This converter enables voltage transformation and charge balancing, allowing standard batteries to be used with high-power recharge stations without requiring expensive 800V-rated battery components.
2Adaptability or versatility
If multiple battery packs are connected in series to support high voltage, then recharge station compatibility is improved, but charge balancing complexity increases
Solution Approach 1:
The DC-to-DC converter incorporates feedback control mechanisms that continuously monitor the charge state of each battery pack and automatically adjust the charging current distribution. This feedback system simplifies charge balancing by making it an automatic, controlled process rather than a manual or complex coordinated operation.
Solution Approach 2:
The DC-to-DC converter performs multiple functions: voltage transformation, charge balancing, and protection. By consolidating these functions into a single device, the overall system complexity is reduced compared to having separate systems for each function.
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
Enables efficient use of high-power recharge stations with standard, affordable batteries and components, reducing charging time and cost while ensuring safe and effective operation of the electric vehicle.
Implementation Method 1
using DC-to-DC converters to balance charge between them
Data Source
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AI summary
A power-supply and recharge group (1) for an electric vehicle comprising: a first battery pack (2a); a second battery pack; a first DC-to-DC converter (22); a second DC-to-DC converter; a low-voltage power-supply source; and a control unit configured to: detect a charge difference between a first and a second battery pack; transfer an electric current from a low-voltage power-supply source to the one of the first and second battery pack having a lower charge, until said charge difference is cancelled; connect the first and the second battery pack to one another in series and recharge them by means of a recharge station on the outside of the vehicle. A direct connection between the DC-to-DC converters can replace the auxiliary low-voltage source.