EV Battery Module Switching for 400V and 800V Charging
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Solution Overview
Problem
Conventional multi-charging systems for electric vehicles suffer from poor charging efficiency and limited charging speed due to the need to boost charging voltage, which can also lead to durability issues in the motor and inverter.
Innovation Solution
A battery system with a voltage switching circuit unit that selectively switches between series and parallel connections of battery modules based on the charger supply voltage, allowing for efficient charging without voltage boosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voltage boosting is used to charge an 800V battery with a 400V charger, then charging compatibility is improved, but charging efficiency deteriorates and motor-inverter durability is compromised
Solution Approach 1:
The battery pack is divided into two independent groups (first group module and second group module), each capable of being connected in series or parallel. This segmentation allows the system to present different voltage configurations (400V or 800V) to the charger without requiring voltage boosting, thereby maintaining charging efficiency while achieving compatibility with both 400V and 800V chargers.
Solution Approach 2:
The system dynamically switches between series and parallel connections of the two battery group modules based on the charger type detected. When a 400V charger is detected, the modules are connected in parallel to present 400V; when an 800V charger is detected, they are connected in series to present 800V. This dynamic reconfiguration eliminates the need for voltage boosting while maintaining optimal charging efficiency.
2Adaptability or versatility
If voltage boosting is used during charging, then charging compatibility is improved, but motor and inverter durability deteriorates
Solution Approach 1:
By segmenting the battery pack into two independently controllable group modules, the system can directly match the charger voltage without requiring the motor-inverter to perform voltage boosting. This eliminates the stress and heat generation associated with boosting operations, thereby preserving motor and inverter durability while maintaining charging compatibility.
Solution Approach 2:
The voltage switching circuit unit acts as an intermediary between the battery pack and the charger, handling the voltage adaptation through series/parallel switching rather than through the motor-inverter. This protects the motor-inverter from the harmful effects of voltage boosting while still achieving compatibility with different charger types.
3Adaptability or versatility
If multi-charging circuit is used for 800V battery charging, then charging capability is achieved, but charging speed is limited
Solution Approach 1:
The system dynamically configures the battery module connections based on the charger capability. When an 800V super-fast charger is detected, the system switches to series connection mode, presenting an 800V battery configuration that enables direct high-speed charging without the limitations of voltage boosting circuits, thereby achieving both charging capability and high charging speed.
Data Source
AI summary
A battery system of an electric vehicle includes a first group module configured by connecting a plurality of battery modules in series, a second group module configured by connecting a plurality of battery modules in series, a voltage switching circuit unit configured between the first group module and the second group module to switch and vary a circuit connection state between the first group module and the second group module between a series connection state and a parallel connection state, and a controller configured to control an operation of the voltage switching circuit unit based on information of a charger connected to the vehicle and battery state information when a battery of the vehicle is charged.