Modular Charge Equalization for Series-Connected Batteries
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Solution Overview
Problem
Existing charge equalization apparatuses for series-connected batteries face challenges in efficiently equalizing lithium ion batteries due to small voltage differences, leading to deteriorated charge equalization characteristics, manufacturing difficulties of transformers with increasing battery counts, and increased voltage stress on diodes.
Innovation Solution
A charge equalization apparatus that divides series-connected batteries into modules for simultaneous intra-module and inter-module charge equalization, using separate intra-module and inter-module charge equalization units with a 1:1 transformer turns ratio to facilitate easy manufacturing and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional charge equalization apparatus with a single transformer and diode is used for series-connected batteries, then the structure is simple, but the charge equalization performance deteriorates with increasing battery counts and small voltage differences
Solution Approach 1:
The patent divides the battery system into multiple modules, each with its own charge equalization unit containing a transformer. Instead of using one large transformer for all batteries, the system segments the equalization function across multiple smaller transformers, each handling a specific module. This segmentation improves charge equalization performance by providing dedicated equalization paths while reducing the complexity of individual transformer designs.
2Quantity of substance
If the number of batteries increases in a series connection, then the total voltage increases, but the voltage difference between individual batteries becomes smaller, leading to deteriorated charge equalization characteristics
Solution Approach 1:
By segmenting the battery system into modules and providing dedicated charge equalization units for each module, the patent enables precise detection and equalization of small voltage differences within each module. The segmentation allows the system to focus on local voltage differences rather than trying to detect small differences across the entire battery string, thereby maintaining measurement precision even as the total number of batteries increases.
3Adaptability or versatility
If a conventional transformer with N primary windings and a single secondary winding is used, then the transformer can handle N batteries, but the manufacturing difficulty increases with increasing N
Solution Approach 1:
The patent adopts a modular approach where each charge equalization unit contains a transformer with a manageable number of primary windings (e.g., 3 windings for a 3-battery module). This segmentation allows manufacturers to produce smaller, simpler transformers with fewer windings, reducing manufacturing difficulty while maintaining adaptability to different battery configurations by simply replicating the modular units.
Solution Approach 2:
The modular charge equalization units are designed to be universal and can be replicated for different battery configurations. Each module uses the same transformer design with standardized windings, making the manufacturing process more consistent and easier to scale. The universal module design maintains adaptability to various battery arrangements without requiring custom transformers for each configuration.
4Device complexity
If diodes are used in the conventional charge equalization apparatus, then the circuit structure is simple, but the voltage stress on diodes increases with increasing battery voltage
Solution Approach 1:
By segmenting the battery system into modules and placing diodes within each module's charge equalization unit, the patent reduces the voltage stress on individual diodes. Each diode only needs to block the voltage of its local module rather than the total voltage of all series-connected batteries. This segmentation significantly reduces the voltage rating requirements for diodes while maintaining relatively simple circuit structures within each module.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables complete charge equalization, enhances performance by inducing magnetizing current in undercharged batteries, and simplifies transformer manufacturing, ensuring effective charge balancing across battery modules.
Implementation Method 1
a transformer T, configured such that it includes N primary windings and a single secondary winding, the N primary windings are connected to a common core... the transformer T... stores energy supplied by the M series-connected batteries and supplies the stored energy to undercharged batteries
Data Source
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AI summary
The present invention relates to a charge equalization apparatus, in which series- connected batteries are divided into modules having certain sizes, and intra-module charge equalization and inter-module charge equalization are simultaneously performed, thus improving charge equalization performance and reducing the circuit size.