Prismatic Battery Cap Plate Current Cutoff Under Pressure Rise
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Solution Overview
Problem
Secondary batteries are prone to thermal runaway, cell explosion, and heat propagation due to overcharging or external short circuits, leading to catastrophic accidents such as fires and explosions, necessitating a safety mechanism to automatically stop current application in abnormal states.
Innovation Solution
A cap plate is hermetically coupled to a prismatic case with a pressure or temperature deformation portion that deforms upon increased pressure or temperature, causing a second part to separate from the electrode lead, thereby disconnecting the electrical connection and preventing further current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure deformation portion is added to the cap plate to enable automatic disconnection upon pressure increase, then safety is improved, but device complexity increases
Solution Approach 1:
The cap plate is divided into a first part (fixed to the case) and a second part (movable relative to the first part). The electrode terminal is segmented between these two parts, allowing the second part to disconnect from the first part when pressure increases, thereby stopping current flow automatically.
Solution Approach 2:
The cap plate structure transitions from a static design to a dynamic one where the second part can move relative to the first part. The pressure deformation portion enables this dynamic response, allowing the structure to automatically adjust its state based on internal pressure conditions.
2Reliability
If a temperature deformation portion is added to the cap plate to enable automatic disconnection upon temperature increase, then safety is improved, but device complexity increases
Solution Approach 1:
The temperature deformation portion utilizes thermal expansion principles where materials expand when heated. When the internal temperature increases due to overheating or thermal runaway, the temperature deformation portion expands or deforms, causing the second part to move and disconnect from the first part, thereby stopping current flow.
3Extent of automation
If the cap plate is designed with movable second part and deformation portions, then automatic current stopping capability is improved, but manufacturing complexity increases
Solution Approach 1:
The cap plate structure performs self-protection by automatically detecting abnormal conditions (pressure or temperature increase) and stopping current flow without external intervention. The deformation portions and movable second part enable this self-service safety mechanism, eliminating the need for external sensors or control systems.
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 solution effectively prevents thermal runaway, cell explosion, and heat propagation by automatically disconnecting the electrical connection in emergency situations, enhancing the safety of prismatic secondary batteries.
Implementation Method 1
a pressure deformation portion configured to deform toward the electrode terminal upon receiving a pressure
Implementation Method 2
a temperature deformation portion configured to deform toward the electrode terminal based on an increase in temperature
Data Source
AI summary
A cap plate is hermetically coupled to an open side of a prismatic case and provided with an electrode terminal. The cap plate includes a first part coupled and electrically connected to the electrode terminal. The first part includes a pressure deformation portion configured to deform toward the electrode terminal upon receiving a pressure. The cap plate includes a second part includes a first portion coupled to the pressure deformation portion of the first part, and a second portion coupled to an electrode lead of an electrode assembly.