Battery Lead Welding Stability via Pre-compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery manufacturing methods face challenges in achieving stable and reliable welding between the upper current collecting plate and the lid, often resulting in defective welds due to variations in welding conditions and pressure, leading to inconsistent internal resistance and battery performance.
Innovation Solution
A method involving a nickel-plated cold rolled steel lead with specific structural features, subjected to compressive stress exceeding its elastic deformation range, is used to weld the lead to the upper current collecting plate, ensuring firm connections and minimizing defective welds by stabilizing the pressure at the point of contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding methods are used to connect the lead to the upper current collecting plate, then the manufacturing process is simple, but the welding quality is unstable and defective welds occur frequently
Solution Approach 1:
The lead is pre-compressed to exceed its elastic deformation range before welding, creating a predetermined compressive stress state. This preliminary action ensures that during welding, the lead maintains stable contact pressure with the upper current collecting plate, eliminating welding quality instability without requiring complex real-time pressure control systems
Solution Approach 2:
The invention changes the stress state parameter of the lead from normal elastic deformation to plastic deformation by applying compressive stress exceeding the elastic deformation range. This parameter change transforms the lead's mechanical properties, enabling it to maintain constant contact pressure during welding, thereby improving weld quality while keeping the manufacturing process relatively simple
2Manufacturing precision
If the lead is not pre-compressed, then the manufacturing process is simpler, but the contact pressure during welding varies causing inconsistent internal resistance
Solution Approach 1:
The lead undergoes preliminary compression beyond its elastic limit to establish a predetermined stress state. This pre-compression ensures that during battery assembly and welding, the lead maintains consistent contact pressure with the upper current collecting plate, guaranteeing uniform internal resistance across all batteries without requiring additional precision control devices
Solution Approach 2:
The lead's own elastic-plastic deformation characteristics are utilized to automatically maintain constant contact pressure. The pre-compressed lead acts as a self-regulating mechanical element that compensates for variations in assembly conditions, ensuring consistent internal resistance through its inherent material properties rather than external control systems
3Reliability
If welding is performed without pre-compression, then the process is faster, but defective welds are difficult to detect
Solution Approach 1:
The lead is pre-compressed to create a known stress state before welding. This preliminary action ensures that any welding defects will manifest as anomalies in the overall battery performance or structure, making them detectable through subsequent inspection methods while maintaining high manufacturing speed
Solution Approach 2:
The pre-compressed state of the lead creates a feedback mechanism where welding quality directly affects the structural integrity and electrical performance of the battery. Defective welds result in measurable deviations in internal resistance or mechanical strength, enabling quality control through performance testing rather than requiring complex real-time welding monitoring
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
This approach significantly reduces the proportion of defective products and achieves high power density batteries with consistent internal resistance, suitable for applications requiring rapid charge and discharge cycles.
Implementation Method 1
subjected to compressive stress exceeding its elastic deformation range
Implementation Method 2
compressive stress exceeding its elastic deformation range of the lead
Implementation Method 3
welding a point of contact between the lead and the upper current collecting plate, in that the point of contact is welded by passing a current between a positive electrode terminal and a negative electrode terminal
Data Source
AI summary
A method for manufacturing highly reliable batteries includes the steps of placing in a battery container an electrode assembly; arranging an upper current collecting plate to be electrically connected to one of the electrodes of the electrode assembly; bringing a lead previously welded to the inner surface of a lid in contact with the upper current collecting plate; and welding the points of contact between the lead and the upper current collecting plate. Also batteries are produced by the method, and a method for inspecting battery including the steps of detecting defective welds by measuring alternating-current resistance of a battery.