Laminated Prismatic Cell Structure for Low-Resistance High Energy Density
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Solution Overview
Problem
Existing lithium batteries face a trade-off between internal resistance and energy density, with thicker electrode plates increasing internal resistance and reducing energy density, while thinner plates decrease capacity and increase manufacturing costs.
Innovation Solution
The laminated cell design includes specific ratios of electrode plate dimensions (6.3×10^2 to 9.4×10^2) and thicknesses (180 μm to 215 μm) to balance internal resistance and energy density, using lithium iron manganese phosphate material with a cladding layer for improved conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode plate is made thicker, then the energy density of the lithium battery increases, but the internal resistance increases and the diffusion distance of lithium ions becomes longer
Solution Approach 1:
The electrode plate is divided into multiple thin electrode plates stacked in sequence. Each thin electrode plate maintains low internal resistance and short lithium ion diffusion distance, while the stack of multiple thin plates collectively provides high energy density, effectively resolving the contradiction between thickness-related performance parameters.
2Reliability
If the electrode plate is made thinner, then the internal resistance of the cell decreases, but the energy density of the lithium battery decreases
Solution Approach 1:
Instead of using a single thick electrode plate, the design employs multiple thin electrode plates stacked together. This segmentation allows each individual plate to remain thin (maintaining low internal resistance) while the collective stack achieves the required energy density through increased total active material volume.
3Reliability
If the electrode plate thickness is reduced, then manufacturing costs increase, but internal resistance decreases
Solution Approach 1:
The electrode plate is segmented into multiple thin plates that can be manufactured using standard thin-plate manufacturing processes, avoiding the need for expensive ultra-thin plate production. The stacked configuration achieves low internal resistance through manageable thickness increments rather than requiring prohibitively thin single plates.
Data Source
AI summary
A laminated cell, a prismatic lithium battery and a battery pack are provided. The laminated cell includes a plurality of cell units stacked in sequence along a first direction, each of the cell units includes a positive electrode plate, a separator and a negative electrode plate that are stacked in sequence, and a separator is disposed between two adjacent ones of the cell units. A ratio of a length to a thickness of the positive electrode plate and a ratio of a length to a thickness of the negative electrode plate are respectively and independently selected from 6.3×102 to 9.4×102, and a ratio of a width to the thickness of the positive electrode plate and a ratio of a width to the thickness of the negative electrode plate are respectively and independently selected 6.3×102 to 9.4×102.