In-situ measurement technique for nondestructive determination of end-of-mixing time during slurry preparation for battery manufacturing process

1 . A method of producing an electrode slurry for use in battery manufacturing, the method comprising:

mixing a plurality of slurry components within an internal volume of a mixing container;

transmitting acoustic signals across the internal volume of the mixing container;

monitoring an acoustic attenuation of the acoustic signals over a period of time;

determining when an end-of-mixing condition is met when the acoustic attenuation reaches a predetermined value; and

stopping the mixing when the end-of-mixing condition is met.

2 . The method of claim 1 , wherein the predetermined value is a target value of the acoustic attenuation.

3 . The method of claim 1 , wherein the predetermined value is a rate of change of an acoustic attenuation coefficient.

4 . The method of claim 1 , wherein the plurality of slurry components comprise carbon and a polyvinylidene fluoride (PVDF) binder.

5 . The method of claim 1 , wherein the acoustic signals are transmitted by a plurality of transducers located at a plurality of heights on the mixing container.

6 . The method of claim 1 , wherein a plurality of acoustic signals are transmitted by an array of transducers.

7 . A method of producing an electrode slurry for use in battery manufacturing, the method comprising:

mixing a plurality of slurry components within an internal volume of a mixing container;

transmitting ultrasonic signals across the internal volume of the mixing container;

monitoring an attenuation of the ultrasonic signals over a period of time;

determining when an end-of-mixing condition is met when the acoustic attenuation reaches a predetermined value; and

stopping the mixing when the end-of-mixing condition is met.

8 . The method of claim 7 , wherein the predetermined value is a target value of the attenuation of the ultrasonic signals.

9 . The method of claim 7 , wherein the predetermined value is a rate of change of the attenuation of the ultrasonic signals.

10 . The method of claim 7 , wherein the ultrasonic signals are transmitted and received by an array of ultrasonic transducers.

11 . A method of producing an electrode slurry for use in battery manufacturing, the method comprising:

mixing a plurality of slurry components within an internal volume of a mixing container;

transmitting acoustic signals across the internal volume of the mixing container;

monitoring an attenuation for the acoustic signals over a period of time; and

adjusting at least one mixing parameter based on the attenuation the acoustic signals.

12 . The method of claim 11 , wherein the acoustic signals are transmitted and received by a plurality of acoustic transducers.

13 . The method of claim 12 , wherein the acoustic transducers are located on an outside of the mixing container.

14 . The method of claim 12 , wherein the acoustic transducers are located on an inside of the mixing container.

15 . The method of claim 12 , wherein the acoustic transducers are located at a plurality of heights on the mixing container.

16 . The method of claim 12 , wherein the acoustic signals are transmitted and received by an array of acoustic transducers.

17 . The method of claim 11 , wherein the mixing parameter is adjusted based on a rate of change of the attenuation of at least one of the plurality of acoustic signals.

18 . The method of claim 11 , wherein the mixing parameter is selected from a group consisting of: a mixing speed, a mixing start, and a mixing stop.

19 . The method of claim 11 , wherein the mixing parameter is selected from a group consisting of a location of a mixing blade within the internal volume and an angle of the mixing blade.

20 . The method of claim 11 , wherein the mixing parameter is a mixing profile.