Battery Storage Controller Managing Uneven SOC Distribution

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Solution Overview

Problem

In storage battery systems with multiple power conditioning systems (PCSes) of different capacities, the State Of Charge (SOC) of batteries varies due to unequal charge/discharge distribution, leading to uneven deterioration and reduced system stability.

Innovation Solution

A controller is introduced to manage charge/discharge requests across multiple PCSes, adjusting the power distribution based on the number and capacity ratio of storage battery modules connected to each PCS, ensuring uniform SOC across all modules through a relational expression that balances the charge/discharge amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the total charge/discharge amount is proportionately divided by multiple PCSes in a storage battery system with different maximum power storage capacities, then the system can operate with multiple PCSes of different capacities, but the SOC of storage batteries varies among PCSes leading to uneven deterioration

Engineering Contradiction:

ImproveAbility to combine PCSes with different maximum power storage capacitiesVSAvoidUniformity of SOC among storage batteries

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by making the charge/discharge amount allocation dependent on the specific characteristics of each PCS and its connected storage battery. Instead of uniform proportional division, each PCS receives a customized charge/discharge amount based on its maximum power storage capacity and the SOC state of its connected battery, ensuring localized optimization for each subsystem while maintaining overall system balance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the control parameter from simple proportional division based on PCS capacity to a more complex allocation method that considers both PCS maximum power storage capacity and the real-time SOC state of connected batteries. This parameter change enables the system to dynamically adjust charge/discharge amounts to maintain uniform SOC across all batteries despite differences in PCS capacities.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If proportional charge/discharge division is used among multiple PCSes, then the control method remains simple, but the SOC uniformity among storage batteries deteriorates when PCSes have different capacities

Engineering Contradiction:

ImproveSimplicity of charge/discharge control methodVSAvoidUniformity of SOC distribution

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces dynamics into the charge/discharge control by making the allocation ratios variable rather than fixed. The control method dynamically adjusts the charge/discharge amount for each PCS based on real-time SOC measurements and the specific capacity characteristics of each PCS-battery pair, enabling adaptive optimization without requiring complex manual configuration or fixed allocation schemes.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If storage batteries with different maximum power storage capacities are connected to different PCSes, then the system can handle diverse power storage needs, but uneven SOC variation leads to reduced system stability

Engineering Contradiction:

ImproveAbility to accommodate different power storage capacitiesVSAvoidSystem stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent implements feedback control by continuously monitoring the SOC of each storage battery and using this information to adjust the charge/discharge amount allocation among PCSes. The control method incorporates SOC feedback from each battery-PCS pair and dynamically modifies the distribution strategy to maintain uniform SOC levels, thereby ensuring system stability despite heterogeneous PCS capacities.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10141753B2Storage battery system

Publication Date: 2018.11.27 TMEIC CORP

AI summary

A storage battery system relating to the present invention includes N PCSes. Each of the N PCSes is connected to an individual storage battery module group. The storage battery module group is formed by connecting one or more storage battery modules in parallel. A maximum power storage capacity of the storage battery modules configuring at least one storage battery module group is different from a maximum power storage capacity of the storage battery modules configuring the other storage battery module groups. A controller determines charge/discharge amounts of the individual PCSes on the basis of a charge/discharge request from an EMS, the maximum power storage capacity of the storage battery module, the number of the storage battery modules and a storage battery capacity ratio.