Assembled Battery Parallel Connection Member Current Limiting
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Solution Overview
Problem
Existing battery packs face safety concerns due to internal short-circuits in secondary battery cells, which can lead to excessive current flow and heat generation, particularly in assembled batteries with multiple cells connected in series or parallel, and current limiting solutions like constant current diodes are costly and complex.
Innovation Solution
An assembled battery design using secondary battery cell series modules connected in series with a first connection member and in parallel with a second connection member, where the second connection member has a higher electrical resistance and lower melting point, acting as a fuse to manage current flow and prevent overheating, and optionally incorporating current breakers at each module to stop output in case of abnormality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current limiting element such as a constant current diode is disposed at a portion where the secondary battery cells are connected in parallel, then generation of excessive electric current is suppressed, but the disposition of the secondary battery cell is limited by the shape of the current limiting element, the conductive member which interconnects the secondary battery cells becomes complicated, and production costs increase
Solution Approach 1:
The patent extracts the current limiting function from a separate component (constant current diode) and integrates it into the connection member itself. The connection member is designed with a specific electrical resistance value that inherently limits current flow, eliminating the need for additional current limiting components and simplifying the overall structure.
Solution Approach 2:
The connection member serves multiple functions simultaneously: it electrically connects battery cells in parallel and inherently limits current flow through its designed electrical resistance. This multi-functionality eliminates the need for separate current limiting elements, reducing device complexity while maintaining safety.
2Reliability
If a current limiting element such as a constant current diode is disposed at a portion where the secondary battery cells are connected in parallel, then generation of excessive electric current is suppressed, but production costs increase
Solution Approach 1:
The patent removes the need for expensive separate current limiting components by integrating the current limiting function directly into the connection member. This reduces the bill of materials and simplifies the manufacturing process, thereby lowering production costs.
Solution Approach 2:
The patent combines the electrical connection function and current limiting function into a single integrated connection member. This merging of functions reduces the total number of components, simplifies assembly, and decreases production costs while maintaining the safety benefit of current suppression.
3Reliability
If the second connection member has higher electrical resistance and lower melting point than the first connection member, then excessive current flow and heat generation are prevented during internal short-circuits, but the configuration becomes more complex
Solution Approach 1:
The patent applies different electrical resistance values and melting points to different connection members based on their specific functions. The first connection member (series connection) has lower resistance for efficient current flow, while the second connection member (parallel connection) has higher resistance to limit current and lower melting point to act as a fuse, optimizing safety and performance locally.
Solution Approach 2:
The patent changes key parameters (electrical resistance and melting point) of the connection members to achieve different functional outcomes. By adjusting these parameters, the second connection member inherently limits current flow and can melt to interrupt circuits during short-circuits, providing passive safety without additional components.
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
This design ensures high safety with a simple configuration and structure, preventing excessive current flow and heat generation during internal short-circuits without the need for special elements, while maintaining low production costs and facilitating handling and operation.
Implementation Method 1
the electrical resistance value of the second connection member is higher than the electrical resistance value of the first connection member
Implementation Method 2
the melting point of a material constituting the second connection member is lower than the melting point of a material constituting the first connection member
Implementation Method 3
excessive current flows in from all other secondary battery cells parallel-connected to the secondary battery cell... the other secondary battery cells which are discharged rapidly produce heat
Data Source
AI summary
An assembled battery includes a plurality of secondary battery cell series modules each having a plurality of secondary battery cells connected in series, wherein in each secondary battery cell series module, the secondary battery cells are connected in series by a first connection member, the secondary battery cell constituting the secondary battery cell series module and the secondary battery cell constituting the secondary battery cell series module adjacent to the above secondary battery cell series module are connected in parallel by a second connection member, the electrical resistance value of the second connection member is higher than the electrical resistance value of the first connection member, and the melting point of a material constituting the second connection member is lower than the melting point of a material constituting the first connection member.