Secondary Battery Electrode Width Ratio for High Current
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Solution Overview
Problem
Secondary batteries with thinner tabs than electrodes face limitations in handling large current inputs and outputs, restricting their ability to achieve high output due to restricted current capacity.
Innovation Solution
The design includes a battery device with positive and negative electrodes having current collector exposed portions and active material layers, where the ratios of these widths satisfy specific equations, allowing for larger current input and output capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the tab width is made thinner than the electrode width (conventional design), then the battery structure is more compact and easier to manufacture, but the current input and output capability is restricted
Solution Approach 1:
The patent applies local quality by creating different width zones on the electrode: the active material layer has a first width while the current collector exposed portion has a second width that is equal to or greater than the first width. This local differentiation allows the tab region to have sufficient width for high current capability while the electrode body maintains its functional active material area, resolving the contradiction between compact structure and high power output.
2Power
If the current collector exposed portion width is increased to improve current capability, then the power output is enhanced, but the active material layer area is reduced
Solution Approach 1:
The patent segments the electrode into distinct functional zones: the active material layer region and the current collector exposed portion region. By separating these functions spatially, the design allows the active material layer to maintain its area for capacity while the exposed current collector portion provides the necessary width for high current capability, thus resolving the trade-off between power and quantity of active material.
Data Source
AI summary
There is provided a secondary battery including a battery device that has a thickness of 3 to 20 mm, and a battery discharge capacity of 3 to 50 Ah, and an exterior material that packages the battery device. The battery device includes a positive electrode that has a positive electrode current collector and a positive electrode active material layer, a negative electrode that has a negative electrode current collector and a negative electrode active material layer, a separator that is interposed between the positive electrode and the negative electrode that are alternately laminated, a positive electrode tab that is electrically connected to a positive electrode current collector exposed portion and is led-out to the outside of the exterior material, and a negative electrode tab that is electrically connected to a negative electrode current collector exposed portion and is led-out to the outside of the exterior material.