Li-Ion Battery Formation for Short-Circuit Screening
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Solution Overview
Problem
Existing methods for detecting conductive foreign substances in lithium-ion secondary batteries, such as stainless steel, are not sensitive enough to identify potential short circuits between positive and negative electrodes within a practical time frame, leading to unreliable battery manufacturing and evaluation.
Innovation Solution
A method involving initial charging at temperatures between -20°C and 15°C, followed by an aging process at temperatures between 30°C and 80°C, and measuring voltage drop quantities to detect short circuits, with specific viscosity ranges for the electrolytic solution to enhance sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection methods are used to identify conductive foreign substances, then the manufacturing process can proceed, but the detection sensitivity is insufficient and cannot detect minute amounts of stainless steel within a practical time frame
Solution Approach 1:
The patent applies preliminary action by performing an initial charging step before the main detection process. This initial charging prepares the battery by localizing metal impurities on the electrode and causing them to precipitate, which enhances the sensitivity of subsequent detection methods and enables detection of minute amounts of conductive foreign substances within a practical time frame
Solution Approach 2:
The patent uses an intermediary substance (electrolyte solution) to facilitate the detection process. The electrolyte solution acts as a mediator that enables the initial charging step to occur, which in turn prepares the system for sensitive detection of conductive foreign substances through voltage drop measurement
2Productivity
If the battery is charged at higher temperatures to accelerate the process, then the detection speed increases, but the reliability of short circuit detection decreases
Solution Approach 1:
The patent applies parameter changes by specifying precise temperature ranges for different process steps: initial charging at -20°C to 15°C and aging at 30°C to 80°C. These controlled temperature parameters enable both efficient processing and reliable detection, resolving the contradiction between speed and accuracy
3Measurement precision
If the battery undergoes extended aging at high temperatures to improve detection accuracy, then detection sensitivity increases, but the manufacturing cycle time increases
Solution Approach 1:
The patent optimizes the aging process by specifying a temperature range of 30°C to 80°C, which balances detection accuracy with manufacturing efficiency. This parameter optimization allows sufficient time for metal impurity precipitation and localization while maintaining a practical manufacturing cycle time
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 detects and eliminates batteries with conductive foreign substances, ensuring a high reliability of lithium-ion secondary batteries by preventing short circuits and maintaining battery performance over time.
Implementation Method 1
an initial charging step of performing initial charging of a secondary battery at a predetermined temperature by localizing metal impurities on an electrode and causing the metal impurities to be precipitated
Implementation Method 2
an aging step of leaving the lithium-ion secondary battery under a temperature environment ranging of equal to or higher than 30° C. and equal to or lower than 80° C. after the initial charging step
Implementation Method 3
a short circuit detecting step of detecting the presence or absence of a short circuit of the lithium-ion secondary battery by measuring a voltage drop quantity of the lithium-ion secondary battery
Data Source
AI summary
A method of manufacturing a lithium-ion secondary battery of the present invention includes at least four steps as follows: an initial charging step of charging the lithium-ion secondary battery, which has not been subjected to initial charging, under a temperature environment ranging of equal to or higher than −20° C. and equal to or lower than 15° C.; an aging step of leaving the lithium-ion secondary battery under a temperature environment ranging of equal to or higher than 30° C. and equal to or lower than 80° C. after the initial charging step; a short circuit detecting step of detecting the presence or absence of a short circuit of the lithium-ion secondary battery by measuring a voltage drop quantity of the lithium-ion secondary battery and comparing the voltage drop quantity with a reference value; and a sorting step of sorting out a lithium-ion secondary battery in which no short circuit is detected.