Battery Control Device Using Current Integration for Temperature Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In battery systems with multiple unit cells connected in series, accurately determining the temperature of each cell for degradation assessment is challenging due to the impracticality of using a temperature sensor for each cell, leading to increased costs and potential errors in degradation status determination.
Innovation Solution
A battery control device with a temperature sensor attached to a predetermined unit cell calculates the integrated amount of current flow and acquires the temperature of that unit cell as representative of all cells when the current flow is below a predetermined value, allowing for internal resistance and SOC-based degradation determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is provided for all battery cells, then temperature detection accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent uses the temperature measurement from one representative battery cell as a copy/estimate for the temperature of all other cells. Instead of measuring each cell individually, the system copies the temperature data from a single cell (or limited cells) to represent the entire battery pack, thereby reducing the number of sensors needed while maintaining acceptable measurement accuracy for degradation assessment
Solution Approach 2:
The temperature sensor attached to a single battery cell serves a universal function for monitoring the entire battery pack's thermal state. The measured temperature from one cell is used to assess the degradation status of all cells, making the temperature measurement system multi-functional rather than requiring dedicated sensors for each cell
2Measurement precision
If a temperature sensor is provided for all battery cells, then degradation determination accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The system copies temperature information from a single measured cell to represent all cells in the battery pack. This approach allows accurate degradation determination to be achieved without the high manufacturing cost of installing multiple temperature sensors, as the temperature data from one cell is reused for assessing the entire pack's health status
Solution Approach 2:
The patent changes the approach from measuring multiple parameters (temperature of each individual cell) to measuring a single parameter (temperature of one representative cell) and using it for multiple assessment purposes. This parameter change reduces manufacturing cost while maintaining the capability to determine degradation accurately through internal resistance and SOC measurements
3Device complexity
If temperature sensors are reduced in number, then device cost is reduced, but temperature detection accuracy deteriorates
Solution Approach 1:
The system compensates for reduced temperature sensor quantity by copying the temperature measurement from the single measured cell to represent all cells. This copying approach maintains sufficient temperature detection accuracy for degradation assessment purposes, even though physical sensors are reduced in number
Solution Approach 2:
The patent introduces an intermediary approach where the temperature of one cell serves as a proxy or mediator for the temperature of all other cells. Instead of directly measuring each cell's temperature, the system uses the representative cell's temperature as an intermediary value to infer the thermal state of the entire battery pack
Data Source
AI summary
A battery control device incorporated in a battery system including a battery pack with a plurality of unit cells connected in series and a temperature sensor attached to a predetermined unit cell of the plurality of unit cells. In the battery control device, an integrated amount calculator calculates an integrated amount of current flow since start of current conduction through the battery pack. A temperature acquirer acquires a temperature of the predetermined unit cell detected by the temperature sensor as a temperature of each of the plurality of unit cells on a condition that the integrated amount of current flow calculated by the integrated amount calculator is smaller than a predetermined value.