Implantable Battery Tab Welding with Conductive Alignment Pin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Implantable medical device batteries face issues with weld failure due to stress concentration at the root of the welds, leading to reduced battery capacity and power capability, as well as internal shorting, caused by mechanical forces during battery discharge.
Innovation Solution
Incorporating an electrically conductive alignment member, such as a consumable pin, that extends through the stack of electrode tabs and spacers, allowing deeper weld penetration and reducing stress concentration at the weld roots, thereby enhancing the weld's strength and resistance to mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional welding methods are used on electrode tabs, then the battery can be assembled, but stress concentration occurs at the weld roots leading to weld failure
Solution Approach 1:
A pin is introduced as an intermediary element that extends through the electrode tabs and is welded to them. The weld penetrates through the tabs into the pin, creating a stronger anchor point that distributes stress away from the tab roots and prevents weld failure during battery operation.
2Strength
If weld penetration is increased to improve strength, then weld strength improves, but the complexity of the manufacturing process increases
Solution Approach 1:
The pin is pre-positioned through the electrode tabs before the welding process begins. This preliminary arrangement ensures proper alignment and allows the welding process to proceed systematically with controlled penetration into the pin, simplifying the overall manufacturing process while achieving strong welds.
3Reliability
If deeper weld penetration is achieved, then stress concentration is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The pin structure itself facilitates proper weld penetration by providing a target geometry that guides the welding process. The weld naturally penetrates through the tabs into the pin with appropriate depth control, reducing the need for complex external precision control systems while ensuring reliable stress distribution.
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
The use of an electrically conductive alignment member within the battery assembly significantly reduces stress concentration at the weld roots, resulting in stronger welds that can withstand higher loads and maintain electrical connectivity, thus improving battery capacity and power performance.
Implementation Method 1
a weld on a side of the electrode stack extending from the first tab to the second tab, wherein the weld penetrates into the alignment member
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In some examples, a battery assembly for an implantable medical device may include an electrode stack comprising a plurality of electrode plates. The plurality of electrode plates may comprise a first electrode plate including a first tab extending from the first electrode plate and a second electrode plate including a second tab extending from the second electrode plate, an alignment member extending through the first tab and the second tab, and a weld on a side of the electrode stack extending from the first tab to the second tab, wherein the weld penetrates into the alignment member.