Parallel Battery Module Current Balancing Across Cell Blocks

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Solution Overview

Problem

In battery modules with multiple cell blocks connected in parallel, variations in performance and deterioration between cell blocks lead to uneven current loads and increased deterioration, which can result in excessive current variations and uneven wear, necessitating a solution to balance and stabilize the charging and discharging process.

Innovation Solution

A charge and discharge control device and method that utilizes a controller to monitor and adjust current flows through each cell block based on their specific current loads and parameters, such as capacity and internal resistance, to maintain balanced current loads and suppress variations, particularly by controlling the State of Charge (SOC) within predetermined ranges to prevent excessive current fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If cell blocks are connected in parallel to achieve high capacity, then the battery capacity is improved, but current load variations between cell blocks increase

Engineering Contradiction:
Improvebattery capacityVSAvoidcurrent load uniformity
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by individually controlling the current load of each cell block based on its specific characteristics (capacity, internal resistance, temperature). The controller adjusts charging/current parameters for each cell block separately, ensuring that each cell block operates within its optimal range, thereby preventing excessive current load variations while maintaining high overall capacity.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If cell blocks with different performances are used to meet capacity requirements, then the battery capacity is improved, but deterioration variations between cell blocks increase

Engineering Contradiction:
Improvebattery capacityVSAvoiddeterioration uniformity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting charging parameters (current, voltage, temperature) for each cell block based on real-time monitoring of their performance parameters (capacity, internal resistance). This allows the system to accommodate cell blocks with different performances while maintaining uniform deterioration rates through adaptive parameter optimization.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If individual current control for each cell block is implemented, then current load balance is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent load balanceVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies merging by integrating multiple control functions into a single centralized controller that manages all cell blocks. The controller combines monitoring, calculation, and adjustment functions for all cell blocks, reducing the need for separate control systems for each cell block while maintaining individual current load balance through unified management.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3852219B1Charge and discharge control device, charge and discharge system, charge and discharge control method, and charge and discharge control program
Publication Date: 2023.10.04 KK TOSHIBA
  • EP3852219B1 patent drawingFigure 1
  • EP3852219B1 patent drawingFigure 2
  • EP3852219B1 patent drawingFigure 3A~3C

AI summary

According to an approach, there is provided a charge and discharge control device (7) that controls charging and discharging of a battery module (2) in which a plurality of cell blocks (B1 to Bn), each including one or more unit cells (11), are connected in parallel to one another. A controller (12) of the charge and discharge control device (7) controls a current flowing through each of the cell blocks (B1 to Bn) based on at least one of a current load of each of the cell blocks (B1 to Bn) or a parameter relating to the current load.