UniBB Module Active Balancing for Parallel Electrochemical Accumulators
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Solution Overview
Problem
Existing electrochemical energy stores connected in parallel face challenges in balancing state of charge (SOC) across modules, leading to potential overcharging or deep discharge due to differences in cell constitution, which can result in damage or degradation, and existing solutions either incur high energy losses or fail to prevent undesired operating states.
Innovation Solution
The use of UniBB modules, configured as both voltage and current sources, allows for controlled charge shifting between modules with different SOC levels, operating in various modes (buck, boost, regulated, unregulated) to balance SOC while minimizing energy expenditure and wear, and modules not involved in balancing are put into blocking or bypass modes to optimize the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If modules are connected in parallel to provide high currents, then current capability is improved, but compensation currents flow between modules causing undesired operating states
Solution Approach 1:
A current source is introduced as an intermediary component between parallel-connected modules to actively compensate for compensation currents. The current source detects voltage differences between modules and injects compensating currents to prevent undesired operating states, thereby maintaining system reliability while preserving the high current capability provided by parallel connection.
2Ease of operation
If cells are connected in series for charging and discharging, then charging/discharging control is simplified, but differences in cell constitution cause unequal state of charge leading to overcharging or deep discharge
Solution Approach 1:
A monitoring system continuously measures the state of charge and voltage of each cell in the series connection. When differences in cell constitution cause unequal SOC, the system provides feedback to a control unit that adjusts charging currents individually for each cell or activates balancing circuits to equalize SOC, preventing overcharging and deep discharge while maintaining simplified series charging operation.
3Reliability
If balancing is performed between cells with different SOC, then charge equalization is achieved, but high compensation currents cause energy losses and wear
Solution Approach 1:
The balancing system dynamically adjusts balancing current parameters based on the degree of SOC difference between cells. When SOC differences are small, lower balancing currents are applied to minimize energy losses and wear. When SOC differences are large, higher currents are temporarily applied to achieve faster equalization. The system also switches between different balancing modes (resistive balancing, active balancing using UniBB modules) depending on operational conditions to optimize the trade-off between balancing speed and energy efficiency.
Data Source
AI summary
An electrochemical energy accumulator (100) and a method for balancing a multiplicity of sections (S1, S2, S3) of electrochemical accumulator modules (10) connected in parallel with one another by means of at least one UniBB module are proposed. In this context, the following steps are carried out: detecting (S100) a first state of charge (I) of a first accumulator module (M1), detecting (S200) a second state of charge (II) of a second accumulator module (M2), wherein the second accumulator module (M2) is a UniBB module, and operating (S300) the second accumulator module (M2) as a power source in order to adapt the first stage of charge (I) and the second state of charge (II) to one another.