In-situ stress detector for an electrode and a method of use

1. A stress detector for detecting an in-situ stress profile of an electrode of a battery comprising a current collector having a surface on which electrode active material is applied, the stress detector comprising:

a liquid cell;

a holder configured to attach to one end of the current collector so that the electrode is cantilevered in the liquid cell;

a piezo sensor comprising a piezo material in the liquid cell and having a movable end configured to contact the current collector at an end opposite the holder and a fixed end fixedly engaged within the liquid cell on a wall opposite the holder; and

a measurement sensor in contact with the piezo sensor.

2. The stress detector of claim 1 , wherein the measurement sensor is a voltmeter configured to measure a voltage generated from a change in shape of the piezo sensor.

3. The stress detector of claim 1 , wherein the piezo sensor is non-conductive.

4. The stress detector of claim 1 , wherein the piezo sensor is a piezo thin film.

5. The stress detector of claim 4 , wherein the piezo thin film is a polyvinylidene fluoride material.

6. The stress detector of claim 1 , wherein the measurement sensor is in contact with the movable end of the piezo sensor.

7. The stress detector of claim 1 , wherein the measurement sensor is configured to measure a movement of the piezo sensor.

8. A stress detector for detecting an in-situ stress profile of an electrode in a liquid cell representing a lithium ion battery, the stress detector comprising:

the electrode comprising a current collector having a surface on which electrode active material is applied, opposing ends of the current collector remaining uncovered;

a holder configured to attach to one end of the current collector so that the electrode is cantilevered in the liquid cell;

a piezo sensor comprising a piezo material in the liquid cell and having a movable end configured to contact the current collector at an end opposite the holder and a fixed end fixedly engaged within the liquid cell;

a measurement sensor in contact with the piezo sensor;

a separator spaced from the electrode active material opposite the current collector;

lithium metal spaced from the separator opposite the electrode active material; and

electrolyte filling the liquid cell.

9. A method for in-situ detection of a stress profile of an electrode, the method comprising:

suspending the electrode in a liquid cell comprising a piezo sensor, the electrode comprising a current collector having a surface on which electrode active material is applied, opposing ends of the current collector remaining uncovered, by:

attaching a fixed end of the current collector to the liquid cell; and

contacting a movable end of the current collector opposite the fixed end with a movable end of the piezo sensor, wherein the piezo sensor is fixedly attached at an opposite end to the liquid cell;

cycling the liquid cell through charge and discharge;

measuring a movement of the movable end of the piezo sensor with a measurement meter.

10. The method of claim 9 , wherein the measurement sensor is a voltmeter that measures a voltage generated from a change in shape of the piezo sensor.

11. The method of claim 9 , wherein the piezo sensor is non-conductive.

12. The method of claim 9 , wherein the piezo sensor is a piezo thin film.

13. The method of claim 12 , wherein the piezo thin film is a polyvinylidene fluoride material.

14. The method of claim 9 , wherein the liquid cell represents a lithium ion battery, the liquid cell comprising:

a separator spaced from the electrode active material opposite the current collector;

lithium metal spaced from the separator opposite the electrode active material; and

electrolyte filling the liquid cell.

15. The method of claim 9 , wherein the measurement sensor is in contact with the movable end of the piezo sensor.

16. The method of claim 9 , wherein the fixed end of the piezo sensor is attached to a wall of the liquid cell.

17. The method of claim 16 , wherein the fixed end of the current collector is attached to a wall of the liquid cell opposite the fixed end of the piezo sensor.