Battery Control Unit for Series-Connected Battery Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery charging systems for series-connected batteries face inefficiencies due to varying deterioration rates, leading to prolonged charging times as batteries are switched between constant current and voltage charging based on individual voltage thresholds, resulting in incomplete capacity utilization.
Innovation Solution
A battery control unit with switching units and a control unit that aligns the remaining chargeable capacity of all batteries to a common switching threshold, allowing simultaneous constant voltage charging once all batteries reach this threshold, thereby shortening the overall charging time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual batteries are bypassed when reaching charge end voltage in series-connected battery systems, then overcharging is prevented, but charging time increases due to sequential CCCV charging cycles
Solution Approach 1:
The charging process is segmented into two distinct phases: a constant current charging phase where all batteries are charged simultaneously at high current, and a constant voltage charging phase where batteries are charged individually after bypassing those that reach the threshold. This segmentation allows the system to maximize charging speed during the initial phase while ensuring safety during the final phase.
Solution Approach 2:
The system performs preliminary constant current charging on all batteries simultaneously before any battery reaches the charge end voltage. By aligning the charge switching voltage and charging all batteries to this threshold first, the system prepares all batteries for the subsequent constant voltage phase, preventing the need to wait for individual batteries to reach different voltage levels sequentially.
2Reliability
If charging current is reduced to match the battery reaching charge end voltage first, then CCCV charging is maintained, but overall charging speed decreases
Solution Approach 1:
The charging system dynamically transitions between two charging modes: a high-speed constant current mode where all batteries are charged simultaneously, and a constant voltage mode where individual batteries are charged after bypassing those that reach the threshold. This dynamic switching allows the system to operate at maximum speed during the constant current phase while maintaining safety compliance during the constant voltage phase.
Solution Approach 2:
The system changes the charging parameters by introducing a charge switching voltage threshold that triggers a mode transition. When batteries reach this threshold during constant current charging, the system switches to constant voltage charging for those specific batteries while continuing constant current charging for others, thereby optimizing both speed and safety.
3Reliability
If batteries are charged sequentially to different voltage levels, then individual battery requirements are met, but capacity utilization is incomplete
Solution Approach 1:
The system merges the charging processes of multiple batteries by charging all of them simultaneously during the constant current phase until they all reach the charge switching voltage. This merging approach ensures that all batteries are charged to the same level concurrently, maximizing capacity utilization while still allowing individual bypassing when needed during the subsequent constant voltage phase.
Solution Approach 2:
The system maintains continuous charging action on all batteries during the constant current phase without interruption or sequential pausing. By keeping all batteries in the charging circuit simultaneously and charging them at the same time, the system eliminates idle time and ensures continuous useful action, thereby maximizing productivity and capacity utilization.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A battery control unit includes a plurality of switching units, a control unit, a charger configured to charge batteries, and a charging control unit. The plurality of switching units is respectively provided for a plurality of batteries connected in series, and are configured to switch between a connected state and a non-connected state. The connected state is a state that a corresponding battery is connected in series with other batteries and a non-connected state is a state that the corresponding battery is disconnected from a series connection with the other batteries. The control unit is configured to determine whether each voltage of the plurality of batteries reaches a charge end voltage during charging, and to control the switching unit corresponding to the battery which is determined to reach the charge end voltage to switch to the non-connected state.