Parallel Battery String Control by Available Capacity
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Solution Overview
Problem
Existing battery systems with multiple parallel-connected battery strings, each comprising a battery, an inverter, and a transformer, face inefficiencies in charging and discharging processes when batteries have either identical or varying maximum charge capacities, as prior art methods require distinct maximum charge capacities for efficient operation.
Innovation Solution
A control device distributes total charge or discharge outputs across battery strings based on their currently available capacities, prioritizing strings with higher available capacity for charging and discharging, and dynamically adjusts the number of simultaneously utilized battery strings to optimize output distribution and minimize parallel operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If batteries with identical maximum charge capacities are used in parallel battery strings, then system uniformity and ease of manufacturing are improved, but efficient charging and discharging operation cannot be achieved according to prior art
Solution Approach 1:
The control device dynamically determines the state of charge of each battery and dynamically adjusts the distribution of charge and discharge outputs. Instead of requiring static differences in battery capacities, the system adapts in real-time based on actual state of charge levels, allowing identical batteries to operate efficiently through dynamic control adjustments.
Solution Approach 2:
The system changes the operational parameters by distributing charge and discharge outputs based on the state of charge rather than fixed capacity differences. This parameter-based distribution approach allows identical batteries to be used while maintaining efficient operation through continuous monitoring and adjustment of charge states.
2Productivity
If batteries with different maximum charge capacities are used in parallel battery strings, then efficient charging and discharging can be achieved according to prior art, but system complexity and manufacturing difficulty increase
Solution Approach 1:
The control device performs multiple functions: it determines the state of charge of each battery, distributes the charge output accordingly, and manages the parallel battery strings. This universal control approach replaces the need for physically different batteries with a single control system that handles diverse operational requirements through software or control logic.
3Power
If all battery strings are utilized simultaneously for charging or discharging, then total output capacity is maximized, but the number of simultaneously used strings increases system complexity
Solution Approach 1:
The control device automatically manages the utilization of battery strings based on their state of charge without requiring external intervention. It self-adjusts which strings are active and to what extent, optimizing the number of simultaneously used strings based on real-time conditions rather than fixed configurations.
Data Source
AI summary
A method for operating a battery system connected to an electric energy system, having battery strings connected in parallel, including a battery, an inverter and a transformer Each battery is chargeable and dischargeable. Each battery has an installed, maximum charge capacity and a capacity that is available in the current operating state. During discharging the currently available capacity corresponds to a state-of-charge of the respective battery, and during charging the currently available capacity corresponds to a difference between the maximum charge capacity and the state-of-charge of the respective battery. A total charge output requested during the charging of the battery system and/or a total discharge output requested during the discharging of the battery system is distributed as part outputs over the battery strings and thus over the batteries dependent on the currently available capacities of the batteries of the battery strings connected in parallel.