OPTICAL MONITORING OF BATTERY HEALTH

• US 20150155605A1
• Filed: 08/09/2013
• Published: 06/04/2015
• Est. Priority Date: 08/10/2012
• Status: Active Grant

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Dvorsky, James E., Risser, Steven M., Saunders, James H., Morrow, C. Alexander, Nippa, David W.
• Granted Patent: US 10,439,255 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 1/07 Non contact-making probes
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/457 comprising three or more layers
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Light is transmitted through or from a separator of a battery cell or scattered within a battery cell and received by one or more light detectors. The light that is normally transmitted through the separator is scattered, absorbed, wavelength-shifted or otherwise distorted by an impending fault in the vicinity of or within the separator. The change in light due to the impending fault is measured by a detector and a signal from the detector is processed to identify the impending fault so that a warning can be generated indicative of the impending fault.

Claims

1. A battery cell structure for monitoring the development of impending faults of the battery cell comprising:

a battery cell separator formed of a light transmitting material that has light transmission characteristics that are a function of the state of impending faults of the battery cell including said separator;

a first optical fiber for transmitting light into said separator and being integrated into said separator;

a second optical fiber for receiving light transmitted through said separator and being integrated into said separator;

a light source coupled to said first optical fiber; and

a light detector coupled to said second optical fiber;

wherein the fault state of a first portion of said battery cell associated with said second optical fiber can be determined.

2. The battery cell structure for monitoring the fault state of the battery cell of claim 1 wherein the cell separator is formed as a gelled polymer membrane.

3. The battery cell structure for monitoring the fault state of the battery cell of claim 1 wherein the cell separator is formed as a porous polyolefin drawn to produce a highly porous membrane.

4. The battery cell structure for monitoring the fault state of the battery cell of claim 3 wherein an associated electrolyte is selected so that its refractive index is within a range corresponding to the range of refractive index of the highly porous membrane.

5. The battery cell structure for monitoring the fault state of the battery cell of claim 4 wherein the associated electrolyte is an ionic liquid.

6. The battery cell structure for monitoring the fault state of the battery cell of claim 1 further comprising:

a third optical fiber for receiving light transmitted through said separator and being integrated into said separator; and

a light detector coupled to said third optical fiber;

wherein the fault state of a second portion of said battery cell associated with said third optical fiber can be determined.

7. The battery cell structure for monitoring the fault state of the battery cell of claim 1 further comprising an outer layer on at least one side of said separator imparting waveguide characteristics to said separator.

8. The battery cell structure for monitoring the fault state of the battery cell of claim 7 wherein the at least one side of the separator includes spaced apart regions of reduced porosity.

9. The battery cell structure for monitoring the fault state of the battery cell of claim 8 wherein spacing between the regions of reduced porosity are of the same order of magnitude or smaller than fault structures to be detected.

10. The battery cell structure for monitoring the fault state of the battery cell of claim 7 further comprising an outer layer on first and second sides of said separator imparting waveguide characteristics to said separator.

11. The battery cell structure for monitoring the fault state of the battery cell of claim 7 wherein said outer layer comprises a material having a refractive index lower than that of a core of said separator.

12. A method for monitoring the fault state of a battery cell comprising:

forming a battery cell separator from a light transmitting material having light transmission characteristics that are a function of the fault state of the battery cell including said separator;

integrating a first optical fiber for transmitting light into said separator;

integrating a second optical fiber for receiving light transmitted through said separator into said separator;

coupling a light source to said first optical fiber;

coupling a light detector to said second optical fiber; and

determining the fault state of a first portion of said battery cell associated with said second optical fiber from an output of said light detector.

13. The method for monitoring the fault state of a battery as claimed in claim 12 further comprising:

integrating a third optical fiber for receiving light transmitted through said separator into said separator;

coupling a light detector to said third optical fiber; and

determining the fault state of a second portion of said battery cell associated with said third optical fiber from an output of said light detector coupled to said third optical fiber.

14. The method for monitoring the fault state of a battery as claimed in claim 12 further comprising forming an outer layer on at least one side of said separator to impart waveguide characteristics to said separator.

15. The method for monitoring the fault state of a battery as claimed in claim 14 further comprising forming an outer layer on first and second sides of said separator to impart waveguide characteristics to said separator.

16. The method for monitoring the fault state of a battery as claimed in claim 14 further comprising forming said outer layer of a material to have a refractive index lower than that of a core of said separator.

17. A battery cell structure for monitoring the development of impending faults of the battery cell comprising:

a battery cell separator formed of a light transmitting material that has light scattering characteristics that are a function of the state of impending faults of the battery cell including said separator;

a first optical fiber for transmitting light into said separator and being integrated into said separator;

a second optical fiber for receiving light scattered within said separator and being integrated into said separator;

a light source coupled to said first optical fiber; and

a light detector coupled to said second optical fiber;

wherein the fault state of a first portion of said battery cell associated with said second optical fiber can be determined.

18. The battery cell structure for monitoring the fault state of the battery cell of claim 17 wherein said light transmitting material also has light transmission characteristics that are a function of the state of impending faults of the battery cell including said separator and further comprising:

a third optical fiber for receiving light transmitted through said separator and being integrated into said separator; and

a light detector coupled to said third optical fiber;

wherein the fault state of a second portion of said battery cell associated with said third optical fiber can be determined.

19. The battery cell structure for monitoring the fault state of the battery cell of claim 17 wherein the second optical fiber receives light scattered at a sharp angle relative to an original light propagation direction within said separator.

20. The battery cell structure for monitoring the fault state of the battery cell of claim 17 wherein the cell separator is formed as a gelled polymer membrane.

21. The battery cell structure for monitoring the fault state of the battery cell of claim 17 wherein the cell separator is formed as a porous polyolefin drawn to produce a highly porous membrane.

22. The battery cell structure for monitoring the fault state of the battery cell of claim 21 wherein an associated electrolyte is selected so that its refractive index is within a range corresponding to the range of refractive index of the highly porous membrane.

23. The battery cell structure for monitoring the fault state of the battery cell of claim 22 wherein the associated electrolyte is an ionic liquid.