Prismatic Battery Current Interrupt Structure for Overcharge Sealing
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Solution Overview
Problem
Existing prismatic secondary batteries lack a reliable mechanism to prevent overcharge and maintain sealability, leading to potential leaks and unreliable electrical connections.
Innovation Solution
A secondary battery design featuring a current collector with a through-hole and a deformation plate that deforms upon increased internal pressure, ensuring stable electrical disconnection and sealability through a weld connection, with a thick portion and annular welds for strong connection and easy deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the periphery of the through-hole in the current collector is welded to the deformation plate by means of energy irradiation, then welding can be performed, but the diffuse reflection of energy rays may damage surrounding components and the welding condition may not be stable
Solution Approach 1:
A reflective member is introduced as an intermediary between the energy irradiation source and the through-hole periphery. This reflective member concentrates the diffusely reflected energy rays back onto the welding area, preventing damage to surrounding components while stabilizing the welding condition through concentrated energy delivery
2Reliability
If a current interrupting mechanism is installed in a secondary battery, then overcharge protection is provided, but the flatness of the current collector surface may be compromised affecting weld quality
Solution Approach 1:
The current collector is divided into two functional regions: a first region with a through-hole for current interruption functionality, and a second region with high flatness for reliable welding. This segmentation allows each region to optimize its specific function without compromising the other
Solution Approach 2:
Different surface quality requirements are applied to different regions of the current collector. The second region (welding area) is specifically designed with high flatness, while the first region (through-hole area) accommodates the current interrupting mechanism, allowing local optimization of surface properties for each functional requirement
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 design provides a reliable secondary battery with low internal resistance, immediate current interruption during overcharge, and assured sealability, preventing leaks and ensuring stable electrical connections.
Implementation Method 1
the deformation plate deforms when an internal pressure of the battery case reaches a predetermined value or higher, and the deformation of the deformation plate causes electrical disconnection between the positive electrode plate or the negative electrode plate and the terminal
Implementation Method 2
a portion of the current collector distant from the through-hole is welded to the deformation plate to form a weld
Data Source
AI summary
A secondary battery includes an electrode body including a positive electrode plate and a negative electrode plate; a battery case containing the electrode body; a terminal attached to the battery case; a conductive member having an opening adjacent to the electrode body; a deformation plate that seals the opening, and a current collector. The positive electrode plate and a positive electrode terminal are electrically connected to each other via a first positive electrode current collector, the deformation plate, and the conductive member. The first positive electrode current collector has a through-hole. The deformation plate is disposed to face the through-hole. A portion of the first positive electrode current collector distant from the through-hole is welded to the deformation plate to form a weld.