Method and apparatus for evaluating phase stability of electrode mixture slurry

An apparatus for evaluating phase stability of an electrode mixture slurry, comprising:

• an input module configured to introduce the electrode mixture slurry to a rheometer;
• a shear rate applying module configured to apply a first shear rate, a second shear rate and a third shear rate to the electrode mixture slurry;
• a rate-controlling module configured to control the first shear rate, the second shear rate and the third shear rate when applying the second shear rate is carried out after carrying out a step of applying the first shear rate, wherein the second shear rate is higher than the first shear rate, and a step of applying the third shear rate is carried out after carrying out a step of applying the second shear rate, wherein the third shear rate is equal to the first shear rate, wherein an approximately instantaneous rate of change in shear rate from applying the first shear rate to applying the second shear rate, from applying the second shear rate to applying the third shear rate, or from applying the third shear rate to further applying a fourth shear rate has an absolute value of 100/s2 or more;
• a comparing module configured to compare the shear viscosity at the first shear rate with the shear viscosity at the third shear rate;
• and
• an evaluating module configured to evaluate the electrode mixture slurry as having phase stability, when the shear viscosity after carrying out the step of applying the third shear rate is within ±20% of the shear viscosity after carrying out the step of applying the first shear rate.