Battery Module Voltage Equalization via Series-Parallel Switching
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Solution Overview
Problem
Existing battery devices with multiple cells connected in series suffer from significant power loss due to voltage equalization, which reduces energy efficiency, and may fail to supply power to a starter motor in internal combustion engines when the secondary battery is dead.
Innovation Solution
A battery device with multiple modules, each containing cells connected in series, featuring voltage equalization circuits and a connection switchover structure that switches between serial and parallel connections to minimize power loss, allowing for efficient voltage equalization and power transfer between modules without discharging, and an electric power supply system that uses both the secondary battery and the battery device as power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If voltage equalization is performed by discharging cells in series connection, then voltage equalization of cells is achieved, but significant power loss occurs reducing energy efficiency
Solution Approach 1:
The battery device is divided into multiple battery modules, each with its own voltage equalization circuit. This segmentation allows independent voltage equalization of each module when connected in parallel, avoiding the need to discharge the entire battery string and significantly reducing power loss while achieving voltage equalization.
Solution Approach 2:
The connection state of battery modules is dynamically switched between series and parallel configurations. When voltage equalization is needed, modules are connected in parallel to enable low-loss equalization; during normal operation, they are connected in series to provide required voltage output, thus adapting the system configuration to minimize energy loss.
2Reliability
If secondary battery is used as sole power source, then system simplicity is maintained, but engine starting fails when battery is dead
Solution Approach 1:
The battery device is pre-charged during engine operation through regenerative braking or alternator charging, storing energy in advance. When the secondary battery fails, this pre-stored energy in the battery device can immediately take over to start the engine, ensuring reliability without requiring a completely redundant power supply system.
Solution Approach 2:
The battery device acts as an intermediary power source between the secondary battery and the starter motor. It can accept charge from the secondary battery during normal operation and discharge to the starter motor when needed, providing a buffer that ensures engine start capability while maintaining relatively simple system architecture.
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 configuration reduces total power loss by minimizing voltage equalization losses and ensures reliable power supply to the starter motor even when the secondary battery is dead, enhancing energy efficiency and engine start capability.
Implementation Method 1
The voltage equalization of the multiple battery modules in the state of parallel connection enables the transfer of electric power between the respective battery modules and accordingly does not cause a power loss due to discharging
Implementation Method 2
a connection switchover structure that switches over a connection state of the multiple battery modules between serial connection and parallel connection
Data Source
AI summary
A battery device of the invention has a high-voltage battery unit, which includes three battery modules C1 through C3, three voltage equalization circuits B1 through B3, and six switches SW1 through SW6. Each of the three battery modules C1 through C3 includes plural lithium secondary cells arranged in series. Each of the voltage equalization circuits B1 through B3 works to equalize the voltages of the respective cells included in a corresponding one of the battery modules C1 through C3. The six switches SW1 through SW6 are individually switched on and off to switch over the connection state of the battery modules C1 through C3 between serial connection and parallel connection. In the battery device of the invention, the voltage equalization process activates the voltage equalization circuits B1 through B3 to respectively equalize the voltages of the plural cells included in each of the three battery modules C1 through C3 in the state of serial connection of the battery modules C1 through C3. After completion of the voltage equalization in each of the three battery modules C1 through C3, the voltage equalization process connects the three battery modules C1 through C3 in parallel and equalizes the voltages of the respective battery modules C1 through C3. This arrangement effectively reduces the power loss by the voltage equalization and thus enhances the total energy efficiency of the whole battery device.