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EP-4742363-A1 - BATTERY THERMAL MODEL BASED ON ELECTROCHEMICAL IMPEDANCE SPECTROMETRY

EP4742363A1EP 4742363 A1EP4742363 A1EP 4742363A1EP-4742363-A1

Abstract

Surface temperatures for battery cells in a battery pack can be inferred or estimated using internal or core temperatures of the battery cell and a thermal model. The internal temperature may be generated using electrochemical impedance spectrometry (EIS). Delta values from the EIS estimations to the cell surface temperature may be generated based on a thermal model of the battery. The thermal model of the battery may be created using probe points on the surface of a test battery, such as thermocouples.

Inventors

  • LEVEUGLE, CLAIRE

Assignees

  • Analog Devices International Unlimited Company

Dates

Publication Date
20260513
Application Date
20251103

Claims (15)

  1. A method to estimate a surface temperature of a battery, the method comprising: receiving a first temperature estimation of a battery cell based on at least one impedance measurement from the battery cell, the first temperature estimation representing a volumetric body temperature of the battery cell; generating a delta value for the battery cell based on a thermal model; and modifying the first temperature estimation based on the delta value to generate a second temperature estimation of the battery cell.
  2. The method of claim 1, wherein the second temperature estimation is a surface temperature estimation of the battery cell.
  3. The method of any preceding claim, further comprising: receiving a present condition associated with the battery, wherein generating the delta value is further based on the present condition using the thermal model.
  4. The method of any preceding claim, further comprising: receiving at least one temperature measurement from a thermocouple coupled to the battery, wherein generating the delta value is further based on the at least one temperature measurement.
  5. The method of any preceding claim, wherein the delta value includes a minimum surface temperature delta value and a maximum surface temperature delta value.
  6. The method of any preceding claim, wherein the thermal model includes a look up table.
  7. The method of any preceding claim, wherein the thermal model is created by using probe points on a surface of a test battery.
  8. The method of any preceding claim, wherein the first temperature estimation is based on an electrochemical impedance spectrometry of the at least one impedance measurement.
  9. A system comprising: one or more processors of a machine; and a memory storing instructions that, when executed by the one or more processors, cause the machine to perform operations: receiving a first temperature estimation of a battery cell based on at least one impedance measurement from the battery cell, the first temperature estimation representing a volumetric body temperature of the battery cell; generating a delta value for the battery cell based on a thermal model; and modifying the first temperature estimation based on the delta value to generate a second temperature estimation of the battery cell.
  10. The system of claim 9, wherein the second temperature estimation is a surface temperature estimation of the battery cell.
  11. The system of claim 9 or claim 10, the operations further comprising: receiving a present condition associated with the battery, wherein generating the delta value is further based on the present condition using the thermal model.
  12. The system of any of claims 9 to 11, the operations further comprising: receiving at least one temperature measurement from a thermocouple coupled to the battery, wherein generating the delta value is further based on the at least one temperature measurement.
  13. The system of any of claims 9 to 12, wherein the delta value includes a minimum surface temperature delta value and a maximum surface temperature delta value.
  14. The system of any of claims 9 to 13, wherein at least one of the following applies: (a) the thermal model includes a look up table; (b) the thermal model is created by using probe points on a surface of a test battery; (c) the first temperature estimation is based on an electrochemical impedance spectrometry of the at least one impedance measurement.
  15. A machine-readable storage medium embodying instructions that, when executed by a machine, cause the machine to perform the method of any of claims 1 to 8.

Description

This application claims priority from United States patent application no. 18/941,903 filed 8 November 2024. TECHNICAL FIELD The present disclosure generally relates to battery temperature monitoring, and more particularly, to a technique for estimating surface temperature of a battery using a battery thermal model. BACKGROUND Rechargeable batteries, such as lithium-ion batteries, are commonly used for portable electronics and electric vehicles (EVs), as well as a variety of other applications, such military and aerospace applications. It is important to monitor the temperature of such batteries during a variety of operations, such as fast charge and rapid discharge operations, to maximize the performance of the batteries. For example, temperature monitoring enables maintenance of cell temperature within prescribed boundaries or ranges (maximum and minimum) during fast charging, limitation of current to avoid overheating during rapid discharge, and prevention of damage to a battery due to abnormal usage to ensure safety. SUMMARY The disclosure describes a method to estimate a surface temperature of a battery. The method comprises receiving a first temperature estimation of a battery cell based on at least one impedance measurement from the battery cell, the first temperature estimation representing a volumetric body temperature of the battery cell; generating a delta value for the battery cell based on a thermal model; and modifying the first temperature estimation based on the delta value to generate a second temperature estimation of the battery cell. The disclosure also describes a system comprising one or more processors of a machine; and a memory storing instructions that, when executed by the one or more processors, cause the machine to perform operations: receiving a first temperature estimation of a battery cell based on at least one impedance measurement from the battery cell, the first temperature estimation representing a volumetric body temperature of the battery cell; generating a delta value for the battery cell based on a thermal model; and modifying the first temperature estimation based on the delta value to generate a second temperature estimation of the battery cell. This disclosure also describes a machine-readable storage medium embodying instructions that, when executed by a machine, cause the machine to perform operations: receiving a first temperature estimation of a battery cell based on at least one impedance measurement from the battery cell, the first temperature estimation representing a volumetric body temperature of the battery cell; generating a delta value for the battery cell based on a thermal model; and modifying the first temperature estimation based on the delta value to generate a second temperature estimation of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS Various ones of the appended drawings merely illustrate example embodiments of the present disclosure and should not be considered as limiting its scope. FIG. 1 illustrates a block diagram of example portions of a battery monitoring system.FIG. 2 is a flow diagram of a method for generating surface temperature estimations.FIG. 3 is a flow diagram of a method for generating surface temperature estimations.FIG. 4 shows example portions of a test battery setup.FIG. 5 is a flow diagram of a method for generating a thermal model.FIG. 6 illustrates a block diagram of an example comprising a machine upon which any one or more of the techniques (e.g., methodologies) discussed herein may be performed. DETAILED DESCRIPTION Improved techniques for surface temperature estimations of battery cells are described. Surface temperatures for battery cells in a battery pack can be inferred or estimated using internal or core temperatures of the battery cell and a thermal model. The internal temperature may be generated using electrochemical impedance spectrometry (EIS). Delta values from the EIS estimations to the cell surface temperature may be generated based on a thermal model of the battery. The thermal model of the battery may be created using probe points on the surface of a test battery, such as thermocouples. FIG. 1 illustrates a block diagram of example portions of a battery monitoring system 100. The battery monitoring system 100 includes a battery pack with a plurality of battery cells 102.1-102.n. The plurality of battery cells 102.1-102.n may be provided in different shapes, such as cube with six sides, cylindrical, etc. In the example of FIG. 1, the battery pack includes four rows of twelve battery cells resulting in a total of forty-eight battery cells. The battery monitoring system 100 includes a electrochemical impedance spectrometry (EIS) printed circuit boards (PCBs) 104.1-104.m coupled to the plurality of battery cells 102.1-102.n. The EIS PCBs 104.1-104.m may measure impedance changes in respective battery cells 102.1-102.n. As explained in further detail below, the impedance changes are used to generate in