Mixed-Chemistry Battery Module for Fast-Charge Lithium Plating Control
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Solution Overview
Problem
Existing battery modules with cells of different chemical systems face challenges in achieving uniform fast charging and discharging capabilities while ensuring safety, particularly in preventing lithium plating during fast charging processes.
Innovation Solution
A battery module design that connects first-type and second-type battery cells with different chemical systems, optimizing the conductivity ratio of the electrolyte solution to the coating mass per unit area of their negative electrode plates, ensuring M1 > M2 within specific ranges, to match lithium plating windows and enhance charging safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery cells of different chemical systems are connected in series to form a battery module, then the battery module can achieve higher energy density and safety, but the battery cells exhibit significant differences in charging and discharging characteristics making uniform fast charging difficult
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio of electrolyte solution conductivity to negative electrode plate coating mass per unit area (M1 and M2) within specific ranges. This parameter optimization ensures that battery cells of different chemical systems have matched lithium plating windows, enabling uniform fast charging performance while maintaining safety. The specific parameter ranges (0.08≤M1≤11, 0.03≤M2≤4.62, with M1>M2) directly address the contradiction by adjusting physical-chemical parameters to achieve both high safety and fast charging capability.
2Reliability
If the conductivity ratio M1 and M2 are optimized within specific ranges, then lithium plating is prevented during fast charging, but the design complexity increases due to multiple parameter constraints
Solution Approach 1:
The patent defines specific parameter ranges (0.08≤M1≤11, 0.03≤M2≤4.62, with M1>M2) that directly control the lithium plating window matching between different battery cell types. By establishing these quantitative constraints on the conductivity-to-coating-mass ratio, the patent transforms a complex multi-parameter optimization problem into a manageable parameter specification, enabling fast charging safety without excessive design complexity.
Solution Approach 2:
The patent enables the battery module to self-regulate lithium ion diffusion and prevent lithium plating through the optimized M1 and M2 parameters. The battery cells' inherent chemical characteristics, when matched through these parameter ratios, automatically ensure uniform charging behavior and prevent safety issues during fast charging, reducing the need for complex external control mechanisms.
3Use of energy by moving object
If battery cells with different chemical systems are used, then energy density can be improved, but the charging and discharging characteristics differ significantly affecting uniform performance
Solution Approach 1:
The patent uses parameter changes to harmonize the charging and discharging characteristics of battery cells with different chemical systems. By optimizing the electrolyte conductivity to coating mass ratio (M1 and M2) within specific ranges, the patent ensures that despite different chemical compositions (e.g., ternary vs. lithium iron phosphate), the battery cells exhibit matched lithium plating windows and uniform charging behavior, maintaining stability in charging characteristics while preserving high energy density benefits.
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
The design enables effective fast charging and discharging capabilities while preventing lithium plating, ensuring higher safety and compatibility of lithium ion diffusion paths in the battery module.
Implementation Method 1
a ratio of a conductivity of an electrolyte solution (25° C.) of the first battery cell to a coating mass per unit area of the first negative electrode plate
Implementation Method 2
the first battery cell includes a first negative electrode plate, the second battery cell includes a second negative electrode plate
Data Source
AI summary
The present application relates to a battery module, including a first-type battery cell and a second-type battery cell electrically connected at least in series, the first-type battery cell and the second-type battery cell are battery cells of different chemical systems, the first-type battery cell includes N first battery cell(s), the second-type battery cell includes M second battery cell(s); the first battery cell includes a first negative electrode plate, the second battery cell includes a second negative electrode plate, a ratio of a conductivity of an electrolyte solution (25° C.) of the first battery cell to a coating mass per unit area of the first negative electrode plate is denoted as M1, and a ratio of a conductivity of an electrolyte solution (25° C.) of the second battery cell to a coating mass per unit area of the second negative electrode plate is denoted as M2, M1>M2, and 0.08≤M1≤11, 0.03≤M2≤4.62.