Flexible Power Storage Device with Segmented Pouch Elements
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Solution Overview
Problem
Conventional lithium secondary batteries lack flexibility and are prone to short-circuiting and cracking when curved or bent, making it difficult to create sheet-like batteries with solid electrolytes that are practical for use in flexible electronic devices.
Innovation Solution
A power storage device with a flexible substrate and non-flexible power storage elements arranged two-dimensionally, where each element consists of a sheet-like positive electrode, negative electrode, and electrolyte, with tabs for electrical connection, allowing the device to be curved and bent without losing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If solid electrolyte is used to create thin and flexible battery structure, then flexibility and thinness are improved, but short-circuit risk increases when curved or bent
Solution Approach 1:
The battery is divided into multiple independent pouch-type power storage elements arranged in an array, where each element is sealed independently. This segmentation allows the flexible substrate to bend without causing short-circuits, as the rigid pouch structures maintain their integrity while the overall array flexes.
Solution Approach 2:
The invention uses a composite structure combining flexible substrate material with rigid pouch-type sealed elements. The flexible substrate provides overall flexibility while the sealed pouches maintain structural integrity and prevent short-circuits during bending, creating a composite system that exhibits both flexibility and reliability.
2Shape
If solid secondary battery structure is used, then flexibility is improved, but film flaking and cracks occur due to repeated bending
Solution Approach 1:
By sealing each power storage element in an independent pouch, the film structure is protected from mechanical stress during bending. The pouch structure acts as a protective enclosure that prevents flaking and cracking of the internal films while allowing the overall battery to flex.
Solution Approach 2:
The pouch-type sealing provides beforehand protection to the internal battery components, cushioning them against the mechanical stresses of bending. This pre-protective structure prevents film damage before it can occur during repeated flexing operations.
3Reliability
If conventional rolled battery structure is used, then high capacity and long life are achieved, but flexibility is completely lost
Solution Approach 1:
The conventional rolled battery structure is segmented into multiple smaller pouch-type power storage elements that can be arranged in arrays on a flexible substrate. This segmentation maintains the high-capacity rolled electrode structures within each pouch while allowing the overall battery to flex, thus preserving both capacity and flexibility.
Solution Approach 2:
The invention uses flexible pouch-type shells to enclose the rigid rolled battery structures. These flexible shells allow the battery to bend and flex while protecting the internal rolled structures, effectively decoupling the flexibility requirement from the capacity-storing rolled structure.
Data Source
AI summary
To provide a flexible, highly reliable, and sheet-like power storage device. The power storage device including a flexible substrate; a positive electrode lead and a negative electrode lead over the flexible substrate; and a plurality of power storage elements over the flexible substrate. The plurality of power storage elements each includes a stack body including a sheet-like positive electrode; a sheet-like negative electrode; and an electrolyte therebetween in an exterior body. An edge portion of the sheet-like positive electrode which extends to the outside of the exterior body is electrically connected to the positive electrode lead through a positive electrode tab provided for the exterior body. An edge portion of the sheet-like negative electrode which extends to the outside of the exterior body is electrically connected to the negative electrode lead through a negative electrode tab provided for the exterior body.