Power Battery Pack Series-Parallel Loop Topology

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Solution Overview

Problem

The existing power battery systems in electric vehicles face issues where a short circuit or open circuit in one series-connected battery can cause the entire in-vehicle power battery circuit to malfunction, leading to the vehicle being unable to run, and there is a need to ensure efficient use of increased battery capacity without compromising normal operation.

Innovation Solution

A power battery pack is designed with four single batteries, each comprising two battery units connected in series to form two loops, allowing for parallel connection of these loops to ensure normal operation even if one loop fails, and a test switch assembly with relay switches and state collectors is used to detect faults and disconnect faulty loops, maintaining vehicle functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If power batteries are connected in series by hard wires to provide high output voltage, then the output voltage is improved, but the reliability deteriorates because a short circuit or open circuit in one battery causes the entire in-vehicle power battery circuit to malfunction

Engineering Contradiction:
Improveoutput voltageVSAvoidcircuit reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The power battery system is divided into multiple independent battery packs, each containing series-connected battery units. These packs are then connected in parallel to form the overall power battery system. This segmentation allows individual packs to fail independently without affecting the entire system, resolving the contradiction between maintaining high voltage through series connection and ensuring system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A battery management unit is introduced as an intermediary component to monitor and control the voltage of each battery pack. The management unit detects voltage imbalances and controls switching between series and parallel connections accordingly, enabling the system to maintain reliability while achieving high output voltage through dynamic configuration management.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the number of battery cores is increased to extend electric vehicle travel distance, then the capacity is improved, but the device complexity increases making it difficult to ensure normal operation

Engineering Contradiction:
Improvebattery capacityVSAvoidsystem complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The large number of battery cores are organized into modular battery units, with each unit containing a manageable number of series-connected cores. Multiple units are then arranged in parallel groups. This segmentation reduces system complexity by creating standardized, interchangeable modules while achieving the required total capacity through parallel expansion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each battery unit is designed with universal characteristics, including standardized terminals and management interfaces. The battery management unit can control multiple units through unified protocols, enabling simplified operation and maintenance of large-capacity systems through multi-functional management capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple power batteries are equipped in an electric vehicle to ensure normal running, then the reliability is improved, but the device complexity increases requiring dozens or hundreds of batteries and complex series connections

Engineering Contradiction:
Improvevehicle operation reliabilityVSAvoidbattery system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple battery units are merged into integrated battery packs with unified management systems. Each pack functions as an independent yet controllable entity, reducing the overall number of discrete components needed while maintaining high reliability through parallel redundancy. The management unit coordinates multiple packs as a single system, simplifying control architecture.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2812942B1Power battery pack and power battery system
Publication Date: 2018.03.28 SHENZHEN BYD AUTO R&D
  • EP2812942B1 patent drawingFigure 1~2
  • EP2812942B1 patent drawingFigure 3

AI summary

A power battery pack and a power battery system are provided. The power battery pack comprises: a plurality of single batteries, each single battery comprising a plurality of battery units, in which an nth battery unit in the plurality of battery units in each single battery is connected with an nth battery unit in the plurality of battery units in an adjacent single battery in series to form an nth loop, where n>=1.