Pouch Battery Protection Circuit Board Mounting
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Solution Overview
Problem
Conventional pouch-type lithium secondary batteries face challenges in efficiently attaching a protection circuit board due to limited sealing surface area, leading to potential short-circuits and damage during the bending process of electrode tabs.
Innovation Solution
An improved connection structure where the protection circuit board is attached parallel to the outer case wall, with electrode tabs bent to prevent short-circuits and minimize the sealing surface area, using insulating tapes and an adhesive element for electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection circuit board is mounted on the sealing surface and electrode tabs are bent to connect them, then electrical connection is achieved, but the sealing surface area is reduced and tab damage may occur
Solution Approach 1:
The protection circuit board is repositioned from the sealing surface to the outer surface of the case, utilizing a different spatial dimension. This allows the sealing surface to be fully dedicated to sealing functions while the outer surface accommodates the circuit board, eliminating the area conflict.
Solution Approach 2:
The electrode tabs are pre-bent into a substantially perpendicular orientation relative to the sealing surface before final assembly. This preliminary bending action prepares the tabs for connection to the protection circuit board on the outer surface, ensuring proper alignment and reducing the risk of damage during subsequent assembly steps.
2Reliability
If electrode tabs are bent to connect to the protection circuit board on the sealing surface, then electrical connection is achieved, but tab damage and short-circuits may occur
Solution Approach 1:
The protection circuit board is extracted from the sealing surface location and repositioned to the outer surface of the case. This separation removes the source of harmful bending stresses and short-circuit risks from the sealing area, allowing tabs to connect more safely.
Solution Approach 2:
The outer surface of the case serves as an intermediary platform that facilitates the connection between the battery unit and protection circuit board without requiring direct mounting on the sealing surface. This intermediate location reduces mechanical stress on the tabs during connection.
3Quantity of substance
If the sealing surface area is minimized, then battery capacity increases, but the protection circuit board cannot be properly mounted
Solution Approach 1:
The mounting location for the protection circuit board is shifted from the two-dimensional sealing surface to the outer surface of the case, which provides sufficient area without compromising the sealing surface. This dimensional shift allows both minimal sealing surface area for maximum battery capacity and adequate space for circuit board mounting.
Data Source
AI summary
A pouch-type lithium secondary battery including: a battery unit comprising a positive electrode plate, a separator, and a negative electrode plate, wherein the separator is disposed between the positive and negative electrode plates; electrode tabs extending from each of the positive and negative electrode plates of the battery unit, respectively; a case having a space to accommodate the battery unit and sealing surfaces formed along the periphery of the space, wherein the case is sealed at the sealing surfaces by thermal fusion; and a protection circuit board 600 electrically connected to the electrode tabs. The protection circuit board is disposed parallel to an outer wall of the case. Since the electrode tabs are bent in an upright position with respect to the sealing surfaces, and the protection circuit board electrically connected to the bent electrode tabs is disposed between the outer wall of the case and the electrode tabs, the size of the sealing surfaces of the case can be minimized.