Device for simulating thermal characteristics of a lithium-ion battery

• US 9,622,294 B1
• Filed: 04/02/2014
• Issued: 04/11/2017
• Est. Priority Date: 04/02/2014
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Ostanek, Jason K.
• Primary Examiner(s): Jennison, Brian
• Application Number:
  US14/242,974
• Time in Patent Office: 1,105 Days
• CPC Class Codes: H05B 1/023 Industrial applications
• CPC Class Codes: H05B 3/44 heating conductor arranged within rods or tubes of insulating material

Abstract

The present invention, as frequently practiced, represents a methodology for carrying out thermal management testing. Inventive practice provides desired temperature characteristics without incurring the safety risks associated with Lithium-ion batteries. An exemplary inventive device includes a spiral-wound electrical resistance heater, and simulates the heat generation profile within a Lithium-ion cell through the use of the resistance heater. The construction of the resistance heater is tailored not only to mimic the localized heating profile of the Lithium-ion cell of interest, but also to match thermal properties of the Lithium-ion cell (such as radial thermal conductivity, axial thermal conductivity, and heat capacity). An exemplary inventive device is constructed out of inert materials and hence is inherently safe to carry out thermal management testing, thereby obviating the need for expensive and time-consuming safety qualifications.

Claims

1. A heat simulation device comprising a conductor strip that is emanative of resistive heat, said conductor strip being coiled so as to approximately describe a geometric cylinder, the coiled said conductor strip having different thermal properties at plural different locations of said geometric cylinder, wherein:

said conductor strip is characterized by a length and includes plural longitudinal strip sections along said length, each said longitudinal strip section extending a portion of said length;

said different thermal properties of the coiled said conductor strip at said different locations are associated with different electrical resistances characterizing said conductor strip when said conductor strip is uncoiled so as to be straight in the direction of said length;

a first said longitudinal strip section is characterized by a first said electrical resistance;

a second said longitudinal strip section is characterized by a second said electrical resistance;

the first said electrical resistance and the second said electrical resistance differ from each other.

9. The heat simulation device of claim 1, wherein:

the first said longitudinal strip section includes a first resistive heating element;

the second said longitudinal strip section includes a second resistive heating element;

said first resistive heating element has a first material composition;

said second resistive heating element has a second material composition;

said first material composition and said second material composition differ from each other;

said first material composition is characterized by the first said electrical resistance;

said second material composition is characterized by the second said electrical resistance;

the difference between the first said electrical resistance and the second said electrical resistance is associated with the difference between said first material composition and said second material composition.

10. The heat simulation device of claim 1, wherein:

the first said longitudinal strip section includes a first resistive heating element;

the second said longitudinal strip section includes a second resistive heating element;

said first resistive heating element is characterized by a first undulative structural shape, said first resistive heating element describing a longitudinal waveform profile along a surface of said first resistive heating element;

said second resistive heating element is characterized by a second undulative structural shape, said second resistive heating element describing a longitudinal waveform profile along a surface of said second resistive heating element;

said first undulative structural shape and said second undulative structural shape differ from each other;

said first undulative structural shape is characterized by the first said electrical resistance;

said second longitudinal strip section is characterized by the second said electrical resistance;

the difference between the first said electrical resistance and the second said electrical resistance is associated with the difference between said first undulative structural shape and said second undulative structural shape.

11. The heat simulation device of claim 10, wherein:

said longitudinal waveform profile described by said first resistive heating element is a first square waveform profile;

said longitudinal waveform profile described by said second resistive heating element is a second square waveform profile;

said first square waveform profile and said second square waveform profile differ from each other.

2. A thermal simulator comprising a substantially cylindrical heater and a substantially cylindrical casing having a geometric axis, said heater including at least two strips and fitting approximately coaxially inside said casing, each said strip being rolled up in a generally cylindrical form and including an electrically conductive resistance-heating element that extends approximately the length of said strip, a first said strip including a first said resistance-heating element, a second said strip including a second said resistance-heating element, the first said resistance-heating element being characterized by a first electrical resistance when the first said strip is straightened in the direction of its said length, the second said resistance-heating element being characterized by a second electrical resistance when the second said strip is straightened in the direction of its said length, said first electrical resistance and said second electrical resistance differing from each other, wherein when electrical current is conducted through said at least two strips each rolled up in said generally cylindrical form said heater is characterized by a heater electrical resistance that differs in at least two regions of said heater, a first said region of said heater being characterized by a said heater electrical resistance in accordance with said first electrical resistance, a second said region of said heater being characterized by a said heater electrical resistance in accordance with said second electrical resistance, said heater thereby exhibiting different thermal characteristics in said at least two regions of said heater.

3. The thermal simulator of claim 2 wherein said at least two strips are radially adjacent.

4. The thermal simulator of claim 2 wherein said at least two strips are axially adjacent.

5. The thermal simulator of claim 2 wherein at least one said strip includes electrical insulation that substantially covers said resistance-heating element and that extends approximately the length of said strip.

6. The thermal simulator of claim 2 wherein each said strip includes electrical insulation that substantially covers said resistance-heating element and that extends approximately the length of said strip.

7. The thermal simulator of claim 2 wherein said heater includes at least one insulative separator, each said insulative separator rolled up together with a said strip so as to prevent self-contact of said strip.

8. The thermal simulator of claim 7 wherein each said strip:

has associated therewith a said insulative separator;

includes electrical insulation that substantially covers said resistance-heating element and that extends approximately the length of said strip.

12. The thermal simulator of claim 2 wherein:

said first resistance-heating element is characterized by a first pair of opposite surfaces and a first cross-sectional area between said first pair of opposite surfaces;

said second resistance-heating element is characterized by a second pair of opposite surfaces and a second cross-sectional area between said second pair of opposite surfaces;

said first cross-sectional area and said second cross-sectional area differ from each other;

said first electrical resistance is related to said first cross-sectional area;

said second electrical resistance is related to said second cross-sectional area.

13. The thermal simulator of claim 12 wherein:

said first cross-sectional area is characterized by a first undulating pattern;

said second cross-sectional area is characterized by a second undulating pattern;

said first undulating pattern and said second undulating pattern differ from each other.

14. The thermal simulator of claim 2 wherein:

said first undulating pattern is a first square waveform pattern;

said second undulating pattern is a second square waveform pattern;

said first square waveform pattern and said second square waveform pattern differ from each other.

15. The thermal simulator of claim 13 wherein:

said first undulating pattern and said second undulating pattern each define a repetition of transverse portions of said strip along the length of said strip;

said first undulating pattern and said second undulating pattern differ from each other with respect to at least one of;

thicknesses of said transverse portions;

distances between said transverse portions.

16. The thermal simulator of claim 15 wherein:

said first undulating pattern is a first square waveform pattern;

said second undulating pattern is a second square waveform pattern;

said first square waveform pattern and said second square waveform pattern differ from each other.

17. The thermal simulator of claim 2 wherein:

said first resistance-heating element is characterized by a first material composition;

said second resistance-heating element is characterized by a second material composition;

said first material composition and said second material composition differ from each other,

said first electrical resistance is related to said first material composition;

said second electrical resistance is related to said second material composition.

18. A method for simulating heat characteristics of a battery, the method comprising:

providing at least two strips, each said strip including an electrically conductive resistance-heating element that extends approximately the length of said strip, a first said strip including a first said resistance-heating element, a second said strip including a second said resistance-heating element, the first said resistance-heating element being characterized by a first electrical resistance when the first said strip is in a straightened condition in the direction of its said length, the second said resistance-heating element being characterized by a second electrical resistance when the second said strip is in a straightened condition in the direction of its said length, said first electrical resistance and said second electrical resistance differing from each other;

fitting said at least two strips approximately coaxially inside an approximately cylindrical casing having a geometric axis, wherein said fitting includes coiling each said strip in a generally cylindrical form;

conducting electrical current through said at least two strips while each said strip is rolled up in said generally cylindrical form inside said casing, wherein a first said region of said at least two strips is characterized by said first electrical resistance, and a second said region of said heater is characterized by said second electrical resistance, said at least two strips thereby exhibiting different thermal characteristics in said at least two regions of said at least two strips.

19. The method for simulating of claim 18 wherein said fitting of said at least two strips includes positioning said at least two strips so as to be adjacent to each other in an axial direction.

20. The method for simulating of claim 19 wherein said fitting of said at least two strips includes positioning said at least two strips so as to be adjacent to each other in a radial direction.