Electrode Recessed Conductor Plate for Battery Lead Bonding
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Solution Overview
Problem
The electrical and mechanical connection between the current collector and the lead in power storage devices, such as lithium ion secondary batteries, is not optimal, affecting the reliability of these devices.
Innovation Solution
An electrode design featuring a conductor plate with recessed portions and a composite film with insulative and conductive layers, where the conductive layers are connected to enhance the interface area and bonding strength between the lead and the composite film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional current collector with metal layers is used, then the basic electrical connection is achieved, but the bonding strength and reliability between the current collector and lead are insufficient
Solution Approach 1:
The current collector surface is segmented into recessed portions and flat portions, creating multiple discrete bonding zones. The recessed portions penetrate through the insulative layer to expose conductive layers, forming localized connection points that enhance mechanical interlocking and electrical contact with the lead.
Solution Approach 2:
The insulative layer has non-uniform thickness, being thinner at the recessed portions and thicker at the flat portions. This local variation in thickness creates regions with different bonding characteristics: the recessed portions provide strong electrical connection points while the thicker flat portions maintain electrical insulation, optimizing both connection and isolation functions.
Solution Approach 3:
The current collector uses a composite structure combining an insulative layer (resin film) with metal layers (aluminum or copper) on opposite surfaces. This composite material approach provides both electrical conductivity through the metal layers and mechanical strength plus insulation through the resin film, while the recessed portions expose the conductive metal layers for enhanced lead connection.
2Strength
If the connection area between current collector and lead is increased, then bonding strength improves, but the electrical insulation performance may be compromised
Solution Approach 1:
The connection interface is segmented into discrete recessed portions rather than a continuous contact area. Each recessed portion creates a localized bonding zone that concentrates mechanical strength without requiring extensive contact area, thereby maintaining insulation performance in the intervening regions.
Solution Approach 2:
The insulative layer thickness varies locally: it is thin at recessed portions to allow electrical connection and thick at flat portions to ensure insulation. This spatial variation in insulation thickness enables simultaneous optimization of both bonding strength and electrical insulation performance.
Data Source
AI summary
An electrode for power storage devices includes: a conductor plate having a first surface which has at least one first recessed portion and a second surface located opposite to the first surface, the first surface including a first region located outside the first recessed portion; and a first composite film including a first layer which contains an insulative material, a first electrically-conductive layer and a second electrically-conductive layer, the first layer being provided between the first electrically-conductive layer and the second electrically-conductive layer, wherein the first electrically-conductive layer of the first composite film is connected with the conductor plate at the first recessed portion, and the second electrically-conductive layer of the first composite film is connected with the first electrically-conductive layer at a position overlapping the first recessed portion as viewed in a normal direction of the first region of the conductor plate.