Nonvolatile Memory Retention Sensing for Power-Off Temperature Estimation
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Solution Overview
Problem
Existing battery management systems in electric vehicles struggle to accurately manage battery performance and lifespan due to temperature variations, especially in power-off states, leading to issues like fire risks and reduced charge capacity.
Innovation Solution
A method and storage device that estimate exposure temperature of nonvolatile memory devices in power-off states by generating reference information on retention values, performing monitoring operations, and using retention characteristics to calculate exposure temperature without continuous power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature monitoring is performed continuously using temperature sensors in power-on state, then temperature detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by performing temperature monitoring during the power-off period before the device is fully powered on. The exposure temperature information is captured and stored in advance, so when the device powers on, the temperature management system already has the necessary data to make immediate control decisions, eliminating the need for continuous monitoring during power transitions.
Solution Approach 2:
The nonvolatile memory device performs self-service by autonomously monitoring its own exposure temperature during power-off states and storing this information internally. The device uses its own retention characteristics as a natural temperature indicator, eliminating the need for external temperature sensors and continuous power consumption for monitoring.
2Use of energy by moving object
If temperature monitoring is stopped in power-off state to reduce power consumption, then power consumption is reduced, but temperature management capability is lost
Solution Approach 1:
The patent introduces an intermediary approach by using the retention characteristics of nonvolatile memory as a passive temperature indicator. Instead of actively monitoring temperature with sensors during power-off, the system uses the natural physical property of memory retention degradation at different temperatures as an indirect but reliable temperature proxy, which is then read out when power is restored.
Solution Approach 2:
The patent replaces the mechanical/active temperature sensing system with a passive physical property-based measurement. Instead of using active temperature sensors that require continuous power, the system substitutes with a method that exploits the inherent retention characteristics of nonvolatile memory, which naturally respond to temperature exposure without requiring active measurement during power-off states.
3Use of energy by moving object
If exposure temperature is estimated using retention characteristics of nonvolatile memory, then power consumption is reduced, but measurement complexity increases
Solution Approach 1:
The patent applies universality by making the nonvolatile memory serve multiple functions: it simultaneously performs its primary data storage function and acts as a temperature sensor through its retention characteristics. This multi-functionality eliminates the need for separate temperature sensing hardware and reduces overall system complexity despite the sophisticated measurement algorithm required.
Solution Approach 2:
The patent uses parameter changes by exploiting how the retention characteristic parameter of nonvolatile memory changes with temperature exposure. By monitoring changes in retention values (such as threshold voltage shifts or data hold capability) after power-off periods, the system can infer temperature history without direct measurement, transforming a storage parameter into a temperature indicator.
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 reduces power consumption and enhances battery performance by providing accurate temperature management in power-off states, ensuring efficient control of temperature-vulnerable components.
Implementation Method 1
a retention value indicates retention characteristic of the nonvolatile memory device
Data Source
AI summary
A method of providing an exposure temperature includes generating reference information indicating relationships between an exposure condition and a retention value, where the exposure condition include an exposure temperature and an exposure time of a nonvolatile memory device and the retention value indicates retention characteristic of the nonvolatile memory device, before a power-off time point when the nonvolatile memory device is powered-off, performing a monitoring program operation to write monitoring data in target memory cells included in the nonvolatile memory device, after a power-on time point when the nonvolatile memory device is powered on, generating a measured retention value by performing a monitoring read operation to read data from the target memory cells, and estimating, based on the reference information, a measured exposure temperature corresponding to the measured retention value and a measured exposure time between the power-off time point and the power-on time point.