Systems and methods for determining self-discharge current characteristics of memory cells

Abstract

Systems and methods for determining self-discharge current characteristics of memory cells are disclosed herein. According to one illustrative embodiment, a system for determining a self-discharge current characteristic of a memory cell (or group of memory cells) includes a voltage source, first and second voltage measurement circuits, a current measurement circuit, and a processor. A voltage source provides a potentiostatic voltage to memory cells coupled to the system. A first voltage measurement circuit provides a first voltage resolution for measuring an open circuit voltage across a pair of terminals of the memory cell. The second voltage measurement circuit provides a second voltage resolution substantially higher than the first voltage resolution for measuring the terminal voltage at one of the pair of terminals of the memory cell. The processor performs a test process to determine a self-discharge leakage current characteristic of the memory cell by using the voltage source, the first and second voltage measurement circuits, and the current measurement circuit.

Description

Background technique [0001] Storage batteries, such as nickel-cadmium (NiCad) batteries or lithium-ion batteries, typically lose their charge over a period of time, primarily due to the self-discharge current that occurs in the storage battery. Unfortunately, considering the state of the art, it is practically impossible to completely eliminate the self-discharge current in these memory cells. Furthermore, while testing individual memory cells in a laboratory environment has limited success, measuring the self-discharge current characteristics of each of a batch of memory cells in a manufacturing environment is rather complex and impractical. [0002] More specifically, measuring the self-discharge current parameter of each of a batch of Li-ion cells during manufacturing is impractical for various reasons. Some of these reasons include disadvantages associated with existing lithium storage battery technology, while others are associated with commercially available potentiosta...

AI Technical Summary

Problems solved by technology

Understandably, such a process not only provides an approximation of the self-discharge current characteristics of each Li-ion cell, but also suffers from various other disadvantages, such as test cycles that must extend for several weeks or longer, storage requirements (including controlled environment conditions) and potential hazards during storage (fire, chemical spills, toxic emissions, etc.)

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