Prismatic Battery Tab Welding for Volumetric Energy Density
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Solution Overview
Problem
Secondary batteries for vehicles face challenges in achieving high volumetric energy density due to space constraints in prismatic battery designs, particularly with the arrangement of exposed electrode core portions and the need for additional spaces within the battery case.
Innovation Solution
A method for producing a secondary battery involving an electrode body with positive and negative electrode plates, a sealing plate, external terminals, and current collectors, where tabs are weld-connected to the current collectors to enhance energy density by stabilizing and strengthening the connection, allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery case contains left and right spaces for wound positive and negative electrode core-exposed portions and an upper space between sealing plate and wound electrode body, then the battery structure can accommodate the electrode components, but the volumetric energy density cannot be increased
Solution Approach 1:
The patent merges the positive and negative electrode core-exposed portions to the same side of the battery, eliminating the need for separate left and right spaces. This consolidation allows better space utilization in the battery case, directly improving volumetric energy density while maintaining structural completeness for accommodating all electrode components
Solution Approach 2:
The patent repositions the electrode core-exposed portions from a distributed arrangement (left and right sides) to a concentrated arrangement (one end side), effectively changing the spatial dimension of component layout. This dimensional reorganization optimizes the three-dimensional space utilization within the battery case, enabling higher volumetric energy density
2Quantity of substance
If the electrode body includes positive and negative electrode core-exposed portions in one end part, then the volumetric energy density can be increased, but the connection reliability between current collectors and tabs may be compromised
Solution Approach 1:
The patent applies preliminary protective actions by using current collectors with extended portions that protrude beyond the electrode plates, and by providing sealing plates with through-holes positioned to receive these extended portions. This preliminary positioning ensures reliable electrical connection and mechanical stability before the battery undergoes assembly or operation, preventing connection failures
Solution Approach 2:
The patent introduces current collectors as intermediary components between the electrode tabs and the external terminals. The current collectors extend beyond the electrode plates and are secured to the sealing plate, acting as a mediator that ensures reliable electrical connection while accommodating the compact electrode arrangement needed for high volumetric energy density
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 method results in a highly reliable secondary battery with increased volumetric energy density by securely connecting multiple tabs to the current collectors, optimizing space usage and improving battery performance.
Implementation Method 1
a first connection step of weld-connecting a stack of a plurality of the tabs to the second current collector
Data Source
AI summary
A method for producing a secondary battery including an electrode body having a positive electrode plate and a negative electrode plate, a prismatic outer body having an opening and houses the electrode body, a sealing plate that seals the opening of the prismatic outer body, and a positive electrode external terminal that is electrically connected to the positive electrode plate and attached to the sealing plate. The method includes a fixation step of electrically connecting a first positive electrode current collector to a positive electrode external terminal and fixing the first positive electrode current collector to the sealing plate, a first connection step of weld-connecting a stack of a plurality of positive electrode tabs to the second positive electrode current collector, and a second connection step of weld-connecting the first positive electrode current collector to the second positive electrode current collector after the fixation step and the first connection step.