Folded Battery Terminals for Short Circuit Prevention
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Solution Overview
Problem
Existing battery designs with flat welded electrode tabs face issues of increased short-circuit risk, higher assembly precision requirements, higher scrap rates, uncertain self-discharge, and reduced energy density due to wasted volume and electrode movement against the case under external forces.
Innovation Solution
The battery design features folded positive and negative terminals, with cathode and anode tabs welded together to form terminals that are folded vertically into the case, along with insulating packing tape and holding means like adhesive tape or clamps to secure the electrode stack, minimizing contact risks and optimizing volume utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flat welded electrode tabs are used, then the assembly process is simpler, but the risk of short circuits increases and manufacturing precision requirements increase
Solution Approach 1:
The patent transforms the flat, planar electrode tabs into three-dimensional folded structures. The tabs are bent at specific angles (e.g., 90 degrees) to fold back into the cell housing, moving from a 2D configuration to a 3D configuration. This dimensional change allows the tabs to be securely positioned within the cell without requiring high assembly precision, while simultaneously preventing short circuits by isolating positive and negative tabs through spatial separation.
Solution Approach 2:
The folded electrode tabs are nested within the cell housing structure. The tabs fold back into the internal space of the cell, utilizing the available volume efficiently. This nesting approach secures the tabs within the housing without requiring external mounting structures or complex assembly procedures, thereby maintaining ease of manufacture while improving reliability through secure positioning.
2Device complexity
If flat welded electrode tabs are used, then the device complexity is reduced, but the energy density decreases due to wasted volume
Solution Approach 1:
By folding the electrode tabs into three-dimensional configurations within the cell housing, the patent eliminates large empty spaces that would otherwise be required to accommodate flat tabs. The folded tabs conform to the internal geometry of the cell, maximizing the utilization of available volume for active materials and electrolyte, thereby increasing energy density without significantly increasing device complexity.
3Manufacturing precision
If flat welded electrode tabs are used, then the manufacturing process is less precise, but the electrode stack moves under external forces increasing defects
Solution Approach 1:
The folded electrode tabs are nested within the cell housing, where they are mechanically constrained by the housing walls and internal structures. This nesting configuration prevents the electrode stack from moving under external forces during transportation or use, thereby stabilizing the cell composition without requiring high manufacturing precision for tab positioning.
4Reliability
If folded terminals are used, then the tightness and reliability are enhanced, but the device complexity increases
Solution Approach 1:
The folded terminal structure uses simple geometric folding (e.g., 90-degree bends) rather than complex mechanical assemblies. This dimensional transformation achieves enhanced tightness and reliability through spatial configuration alone, without introducing complex fastening mechanisms, seals, or adjustment components, thereby limiting the increase in device complexity.
Data Source
AI summary
A cell includes a metal case having a positive side and a negative side designed to form a housing, an assembly of stacked electrodes placed inside the housing and including one or more units each having a positive electrode, a negative electrode and a separator between the positive and negative electrodes, wherein the positive electrodes of the one or more units are electrically connected together to form a positive terminal and the negative electrodes of the one or more units are electrically connected together to form a negative terminal, the positive terminal being folded substantially vertically towards the positive side of the case and the negative terminal being folded substantially vertically towards the negative side of the case.