Power Battery Cap Assembly Resistance Member Design
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Solution Overview
Problem
Conventional cap assemblies for power batteries lack a resistor that is moderate in resistance value, small in volume, and heat-resistant, leading to inadequate safety performance during abuse conditions such as overcharging, crush, or nail penetration, as they fail to effectively manage heat energy and prevent explosions.
Innovation Solution
A cap assembly with a resistance member comprising a heat-resistant insulating base body and a heat-resistant metal layer, forming a conductive path that allows for controlled resistance value, high heat resistance, and small volume, enabling effective current cutoff and heat dissipation during external short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single precise resistor with small resistance value is used, then the resistance value is moderate, but the resistor is not heat-resistant and cannot withstand high temperatures during abuse conditions
Solution Approach 1:
The patent employs a composite structure consisting of a heat-resistant ceramic base body with a metal layer deposited on its surface. The ceramic provides thermal stability and heat resistance, while the metal layer provides electrical conductivity and moderate resistance value. This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both heat resistance and appropriate electrical characteristics.
Solution Approach 2:
The patent changes the physical and chemical parameters of the resistor by using sintered ceramic material with specific porosity and density characteristics. The ceramic base body has controlled pore structure and composition that enables it to withstand high temperatures while the metal layer thickness and pattern are optimized to achieve the desired resistance value. This parameter optimization allows the resistor to function reliably under abuse conditions.
2Reliability
If a conventional heat-resistant resistor with small resistance value is used, then the resistor is heat-resistant, but the volume is too large
Solution Approach 1:
The patent uses a thin metal layer deposited on the ceramic base body surface to provide the electrical resistance function. This thin-film approach significantly reduces the volume of the resistor compared to conventional bulk heat-resistant resistors. The metal layer can be applied as a thin coating that maintains electrical functionality while minimizing space occupation within the battery cap assembly.
Solution Approach 2:
The patent extracts the electrical resistance function from a bulky conventional resistor and implements it as a surface-mounted metal layer on the ceramic base body. By separating the structural support function (ceramic base body) from the electrical resistance function (surface metal layer), the design achieves compact dimensions while maintaining heat resistance and electrical performance.
3Volume of moving object
If a conventional carbon membrane resistor with small volume is used, then the volume is small, but the resistance value is too high
Solution Approach 1:
The patent applies local quality by creating a metal layer with spatially varying thickness or pattern on the ceramic base body surface. The metal layer can be designed with different regions having different conductive properties, allowing precise control of the overall resistance value. This localized property variation enables achievement of moderate resistance values while maintaining compact dimensions.
Solution Approach 2:
The patent creates a dynamic balance between the conductive metal layer and the insulating ceramic base body. The metal layer provides conductive pathways while the ceramic provides insulation and structural support. By optimizing the geometry, thickness, and distribution of the metal layer, the design achieves the desired resistance value that is neither too high nor too low, while keeping the overall component volume small.
4Device complexity
If no resistor is used in the cap assembly, then the structure is simple, but the safety performance is inadequate during external short-circuit conditions
Solution Approach 1:
The patent integrates multiple functions into the cap assembly structure. The heat-resistant ceramic base body with metal layer serves as both a structural component of the cap assembly and a functional resistor for safety protection. This multi-functional design provides external short-circuit protection without significantly increasing overall structural complexity, as the resistor is incorporated into the existing cap architecture rather than being a separate additive component.
Solution Approach 2:
The patent introduces the heat-resistant resistor as an intermediary element between the positive electrode terminal and the cap plate. This intermediary component controls the current flow during external short-circuit conditions, preventing dangerous current levels while maintaining normal battery operation. The resistor acts as a protective mediator that enables safe current cutoff without requiring complex additional safety mechanisms.
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 cap assembly effectively controls external short-circuit current and dissipates internal heat energy, preventing fires and explosions during abuse conditions, thereby enhancing the safety performance of power batteries.
Implementation Method 1
The heat-resistant metal layer, the cap plate and the first electrode terminal are electrically connected to form a conductive path, the conductive path passes along the heat-resistant insulating base body positioned between cap plate and the first electrode terminal
Implementation Method 2
the resistance member is able to control the external short-circuit current of the power battery to be within a reasonable range even if an external short-circuit is established when the power battery is under the situation of abuse such as overcharging, the internal heat energy of the power battery is gradually consumed via the resistance member
Implementation Method 3
a heat-resistant insulating base body positioned between the cap plate and the first electrode terminal
Implementation Method 4
the internal heat energy of the power battery is gradually consumed via the resistance member, thereby preventing fire and explosion of the power battery
Data Source
AI summary
A cap assembly of a power battery comprises: a cap plate, a first electrode terminal provided to the cap plate, and a resistance member electrically connected to the cap plate and the first electrode terminal. The resistance member comprises: a heat-resistant insulating base body positioned between the cap plate and the first electrode terminal; and a heat-resistant metal layer provided to a circumferential side of the heat-resistant insulating base body. The heat-resistant metal layer and the cap plate and the first electrode terminal are electrically connected to form a conductive path. The formed conductive path is a curved path, therefore the resistance value of the resistance member can be controlled by controlling the conductive path.