Cylindrical Cell Stack Assembly for Stable PCB Wire Bonding
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Solution Overview
Problem
Existing battery cell assembly methods using wire bonding face challenges with inefficient production times due to glue hardening and safety risks from screws, and require improved cell positioning and fixation.
Innovation Solution
A battery cell stack design with cylindrical through-holes in a cell holder, an electrically insulating layer, and adhesive layers for secure wire bonding, allowing efficient assembly and reduced risk of thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glue is used to secure battery cells in the cell pack, then the cells are held in place, but the manufacturing time is prolonged due to long hardening time and glue releases harmful gases
Solution Approach 1:
The patent extracts the harmful hardening process and harmful gases from the cell fixation system by replacing chemical adhesive with a mechanical positioning system using a cell holder with through-holes that physically secure cells without requiring chemical bonding or hardening time
Solution Approach 2:
The patent replaces the chemical bonding system (glue hardening) with a mechanical positioning system (cell holder with through-holes) that secures cells through physical constraints rather than chemical adhesion, eliminating the need for hardening time and harmful emissions
2Reliability
If screws are used to hold battery cells in place, then the cells are securely fixed, but safety risks increase due to potential short-circuits from dropped screws
Solution Approach 1:
The patent uses a disposable cell holder made of electrically insulating material that is designed to be used once and then discarded with the battery pack, eliminating the need for removable fasteners like screws that could be dropped and cause short-circuits
Solution Approach 2:
The cell holder acts as an intermediary component between the battery cells and the cell pack structure, providing electrical insulation and mechanical positioning without requiring direct metal-to-metal contact that could create short-circuit pathways
3Reliability
If shoulders extending above and below each cell are used in the cell holder, then upward and downward cell movement is restricted, but the device complexity and material usage increase
Solution Approach 1:
The patent segments the cell holder into a simple base structure with through-holes, relying on the adhesive layer and PCB contact to provide the necessary constraints in the vertical direction, rather than creating a complex enclosed structure with shoulders on all sides
Solution Approach 2:
The cell holder's through-holes serve multiple functions: providing mechanical positioning, enabling adhesive bonding, and allowing PCB contact for electrical connection, eliminating the need for separate shoulder structures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates faster production with enhanced safety by minimizing material deflection and contact forces, reducing the risk of fires and explosions, and enabling easier disassembly for recycling.
Implementation Method 1
a first adhesive layer disposed on the electrically insulating layer such that a second side of each of the battery cells is in contact with the first adhesive layer. The battery cell stack further comprises a second adhesive layer provided between and in contact with the PCB and the first side of each of the battery cells
Implementation Method 2
During the wire bonding process, ultrasonic vibrations are used which may cause the cells to vibrate or rotate
Data Source
Figure 1
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AI summary
A battery cell stack (100) is provided. The battery cell stack comprises a plurality of cylindrical battery cells (110) and a cell holder (120). The cell holder comprises a plurality of cylindrical through-holes (122) having a height smaller than a height of a battery cell. Each of the battery cells is arranged in a respective cylindrical through-hole such that the battery cell protrudes at a first side (124) of the cell holder. The battery cell stack further comprises an electrically insulating layer (130) arranged at a second side (126) of the cell holder, and a printed circuit board, PCB, (140) arranged at a first side (112) of the battery cells and configured to electrically interconnect the battery cells. A first adhesive layer (150) is disposed on the electrically insulating layer such that a second side (114) of each of the battery cells is in contact with the first adhesive layer. A second adhesive layer (160) is provided between and in contact with the PCB and the first side of each of the battery cells. Each of the battery cells is electrically connected to the PCB by wire bonding