Prismatic Cell Spacer Ribs for Electrolyte Retention in Battery Packs
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Solution Overview
Problem
Conventional assembled batteries with alternately stacked rectangular batteries and spacers face issues with electrolyte leakage and high-rate degradation due to insufficient electrolyte retention, especially in high-rate charging and discharging applications.
Innovation Solution
The battery design incorporates flat and curved electrode windings with spacers featuring ribs that extend perpendicular to the winding axis, effectively guiding and stocking electrolyte in the curved parts during expansion and returning it to the flat parts during shrinkage, thereby reducing electrolyte shortage and degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spacers with ribs are used to suppress electrolyte leakage, then electrolyte leakage is reduced, but electrolyte retention is insufficient for high-rate charging and discharging
Solution Approach 1:
The spacer is designed with different structural zones: a flat part that contacts the flat region of the electrode winding for stable support, and curved parts that contact the curved regions for electrolyte accumulation. This local differentiation allows simultaneous achievement of leakage suppression and electrolyte retention.
Solution Approach 2:
The curved parts of the spacer are pre-formed to create electrolyte accumulation spaces before the electrode winding expands. When the electrode winding expands during charging, electrolyte is already positioned in the curved parts, preventing leakage and maintaining retention during high-rate operation.
2Stability of the object's composition
If ribs are formed on spacers to pressurize the battery case, then structural stability is improved, but electrolyte distribution becomes insufficient during expansion and shrinkage
Solution Approach 1:
The spacer provides stable structural support through its flat part contacting the flat electrode region, while simultaneously maintaining electrolyte distribution through curved parts that follow the electrode's curved regions. This local functional differentiation resolves the contradiction between structural stability and electrolyte distribution.
Solution Approach 2:
The curved parts of the spacer dynamically adapt to the expansion and shrinkage of the electrode winding. As the electrode expands during charging, the curved parts move outward to maintain contact and electrolyte distribution, providing both structural stability and electrolyte management.
3Ease of manufacture
If conventional spacers are used for battery assembly, then manufacturing simplicity is maintained, but high-rate degradation occurs due to electrolyte shortage
Solution Approach 1:
The spacer incorporates locally differentiated structures (flat and curved parts) that can be integrated into conventional battery assembly processes. This design maintains manufacturing simplicity while the local structural variations provide the electrolyte management needed to prevent high-rate degradation.
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 effectively suppresses electrolyte leakage and reduces high-rate degradation by ensuring efficient electrolyte retention and distribution within the battery, enhancing the battery's performance and longevity.
Implementation Method 1
the ribs pressurize the top and both ends, defined with respect to the width direction, of the battery case
Implementation Method 2
the ribs face the flat part of the electrode winding and extend in a direction approximately perpendicular to the winding axis of the electrode winding
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Provided is a battery pack having prismatic cells and spacers. Each prismatic cell is provided with a rolled electrode assembly, and the rolled electrode assembly has a flat section with a flat outer peripheral surface and two curved sections with a curved outer peripheral surface. Each spacer has a substrate and multiple ribs protruding on at least one side of the substrate, and the ribs are formed so as to face the flat section of the rolled electrode assembly and extend in a direction substantially perpendicular to the rolling axis of the rolled electrode assembly. The ribs have a length of 60 to 100 when the height of the flat section of the rolled electrode assembly is represented by 100, and the relationship 2 ≤ B/A ≤ 10 is satisfied where A is the width of the ribs and B is the distance between adjoining ribs.