High-Capacity Battery Pack Series Connection Design

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Solution Overview

Problem

Conventional battery packs for laptops face challenges in achieving high capacity without parallel connections, which lead to increased defect rates due to cell voltage unbalance and complex assembly processes, resulting in higher manufacturing costs and reduced productivity.

Innovation Solution

A battery pack design featuring a series connection of three or fewer high-capacity battery cells (each with 3 Ah or more) without a parallel connection structure, utilizing a simplified protection circuit module without voltage unbalance adjustment and a pack case with a spacer to manage thickness changes during charging and discharging, reducing manufacturing complexity and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If several low capacity battery cells are connected in parallel to provide desired capacity, then the battery pack capacity is improved, but cell voltage unbalance occurs leading to increased defect rates

Engineering Contradiction:

Improvebattery pack capacityVSAvoiddefect rate

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

Instead of connecting battery cells in parallel to increase capacity (conventional approach), the patent inverts the approach by using series connection of high capacity cells. This eliminates voltage unbalance issues inherent in parallel connections while achieving the desired capacity through higher individual cell capacity (3Ah or more).

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts and removes the voltage unbalance adjustment function from the protection circuit module. By using series connection instead of parallel connection, the source of voltage unbalance is eliminated, making the adjustment function unnecessary and simplifying the circuit design.

Inventive Principle:

Principle #2Taking out (Extraction)

2Quantity of substance

If several battery cells are connected in parallel to achieve high capacity, then the battery pack capacity is improved, but the protection circuit design becomes more complex

Engineering Contradiction:

Improvebattery pack capacityVSAvoidprotection circuit design

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent inverts the conventional parallel connection approach with a series connection approach. This fundamental inversion simplifies the protection circuit design by eliminating the need to manage voltage unbalance between parallel cells, reducing circuit complexity while maintaining high capacity.

Inventive Principle:

Principle #13The other way round (Inversion)

3Quantity of substance

If several battery cells are connected to provide desired capacity, then the battery pack capacity is improved, but manufacturing costs increase due to additional parts

Engineering Contradiction:

Improvebattery pack capacityVSAvoidmanufacturing cost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

By inverting from parallel to series connection, the patent reduces the number of battery cells needed and eliminates complex circuit components for voltage unbalance adjustment. This simplification directly reduces manufacturing costs while achieving the desired capacity through higher individual cell capacity.

Inventive Principle:

Principle #13The other way round (Inversion)

4Quantity of substance

If several battery cells are connected in parallel to achieve high capacity, then the battery pack capacity is improved, but productivity is lowered due to complicated assembly

Engineering Contradiction:

Improvebattery pack capacityVSAvoidassembly productivity

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent inverts the connection strategy from parallel to series, significantly reducing the number of cells and connection points. This simplification of the assembly structure directly improves productivity by reducing assembly complexity and time.

Inventive Principle:

Principle #13The other way round (Inversion)

5Quantity of substance

If parallel connection structure is used to provide high capacity, then the battery pack capacity is improved, but the defect rate increases due to voltage unbalance exceeding malfunction range

Engineering Contradiction:

Improvebattery pack capacityVSAvoiddefect rate

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent fundamentally inverts from parallel to series connection, eliminating the voltage unbalance phenomenon that causes defects in parallel configurations. This inversion resolves the reliability issue while maintaining high capacity through higher individual cell capacity.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP2506335B1Battery pack of high capacity

Publication Date: 2017.02.22 LG CHEM LTD

AI summary

Disclosed herein is a battery pack including a battery cell array including three or fewer battery cells, each of which has an electrode assembly of a cathode/separator/anode structure disposed in a battery case together with an electrolyte in a sealed state, arranged in the lateral direction, the battery cells having a current capacity of 3 amperes (Ah) or more and being electrically connected in series to each other, a protection circuit module (PCM) connected to the upper end of the battery cell array to control the operation of the battery pack, the protection circuit module including a protection circuit, from which a function to adjust voltage unbalance between the battery cells is removed, and a pack case in which the battery cell array and the protection circuit module are disposed.