Non-Aqueous Rechargeable Battery Electrolyte Balance Under Electrode Expansion
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Solution Overview
Problem
Non-aqueous rechargeable batteries, such as lithium-ion batteries, face issues with uneven distribution of electrolyte solution due to expansion and contraction of negative electrode active materials, leading to increased battery resistance during high-rate charge-discharge cycles.
Innovation Solution
The battery design incorporates a specific ratio of parameters A×B to C×D, where A represents the mass of negative electrode active material, B is the lattice volume change, C is the load change, and D is the reciprocal of the spring constant of the positive electrode plate and separator, ensuring the electrolyte solution is evenly distributed by setting E within a range of 0.48 to 0.69, thereby balancing the solution expulsion from the negative and positive electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the non-aqueous rechargeable battery is repeatedly charged and discharged at a high rate, then the battery provides high power output, but the negative electrode active material repeatedly expands and contracts, expelling non-aqueous electrolyte solution out of the electrode body, causing uneven distribution and locally insufficient electrolyte solution, which increases battery resistance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the spring constant of the positive electrode plate within a specific range (0.05 to 0.15 N/mm) to balance electrolyte solution expulsion between positive and negative electrodes. This parameter optimization ensures that during high-rate charge-discharge cycles, the electrolyte solution distribution remains uniform, preventing locally insufficient conditions that would increase battery resistance, thereby maintaining both high power output and low resistance over repeated cycles
2Stability of the object's composition
If the spring constant of the positive plate is set to balance electrolyte solution expulsion, then uneven distribution of electrolyte solution is reduced, but the deformation behavior of the separator during negative electrode expansion is not adequately considered
Solution Approach 1:
The patent merges the consideration of both positive electrode plate and separator deformation behaviors into a unified design approach. By setting the spring constant of the positive electrode plate within the specific range of 0.05 to 0.15 N/mm, the invention simultaneously accounts for the compression effects on both the positive electrode plate and the separator during negative electrode expansion. This combined approach ensures balanced electrolyte solution expulsion from both electrodes while maintaining simple manufacturing processes
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 approach effectively maintains the electrolyte solution distribution, preventing excessive solution expulsion and subsequent resistance increases, ensuring stable battery performance even after multiple charge-discharge cycles.
Implementation Method 1
B represents a lattice volume change amount (nm3) of the negative electrode active material when the non-aqueous rechargeable battery is charged from an SOC of 0% to 100%
Implementation Method 2
D represents a sum (mm/kN) of a reciprocal of a spring constant of the positive electrode plate and a reciprocal of the spring constant of the separator in the stacking direction
Data Source
AI summary
A non-aqueous rechargeable battery includes an electrode body and a non-aqueous electrolyte solution. The electrode body includes positive and negative electrode plates and a separator. The negative electrode plate includes a substrate and a mixture layer applied to opposite surfaces of the substrate. When A represents a sum of a mass (mg/cm2) of an active material in the mixture layer per unit area on each substrate surface, B represents a lattice volume change amount (nm3) of the active material when the battery is charged from SOC 0% to 100%, C represents a change amount of the load (N) acting on the electrode body if the battery is charged from SOC 0% to 100%, D represents a sum (mm/kN) of a reciprocal of the positive electrode plate spring constant and a reciprocal of the separator spring constant, and E=A×B/(C×D) is satisfied, E is between 0.48 to 0.69, inclusive.