Convection-enhanced electrochemical energy storage devices and related methods

Patent metadata

Field	Value
Publication number	US-12218316-B2
Application number	US-202117504909-A
Country	US
Kind code	B2
Filing date	Oct 19, 2021
Priority date	Oct 19, 2020
Publication date	Feb 4, 2025
Grant date	Feb 4, 2025

Abstract

A convection enhanced energy storage system includes an electrochemical cell with a positive electrode, a separator, and a negative electrode, a tank holding an electrolyte, and a pump connected to the electrochemical cell and the tank to circulate the electrolyte. The electrochemical cell has large γ and β values, which has high transport resistance from diffusion and there is limited salt in the electrolyte solution to compensate. A computer system can implement a model of a convection enhanced energy storage system, for example for simulation to select parameters for such an energy storage system. The model includes: a convection term in a Nernst-Planck equation representing the convection enhanced energy storage system; boundary conditions of a cell of the convection enhanced energy storage system to account for forced convection at boundaries; gauging conservation of anions within an external tank; and calculating electrode active area as a function of porosity.

First claim

What is claimed is:

1. A method for determining upper and/or lower limits of convection in a flow cell battery, the method comprising:
circulating a single electrolyte comprising an electroactive species in an electrochemical cell comprising a positive electrode, a separator, a negative electrode, wherein the electromigrative flux of the electroactive species is greater than the sum of the diffusive flux of the electroactive species and the convective flux of the electrolyte;
applying a voltage between the positive electrode and the negative electrode to generate an electromigrative flux of the electroactive species; and
circulating the single electrolyte in the electrochemical cell, wherein the electromigrative flux of the electroactive species is less than a sum of the diffusive flux of the electroactive species and the convective flux of the electrolyte.

2. A method for determining upper and/or lower limits of convection in a flow cell battery, the method comprising:
circulating a single electrolyte in an electrochemical cell comprising a positive electrode, a separator, a negative electrode, wherein the electromigrative flux of the electroactive species is greater than the sum of the diffusive flux of the electroactive species and the convective flux of the electrolyte; and
applying a voltage between the positive electrode and the negative electrode to generate an electromigrative flux of an electroactive species; and
circulating the single electrolyte in the electrochemical cell, wherein a ratio of an applied current density to an effective diffusivity is greater than 1 and wherein a ratio of a convective flowrate to an initial electrolyte concentration is greater than 1.

3. The method of claim 2 , wherein:

I
app

⁡

(

1
-

t
+

)

⁢
L

F
⁢

⁢

D
eff

⁢

c
initial

>

0.5
⁢

⁢
and
⁢

⁢

Q
A

⁡

(

1
-

t
+

)

F
⁢

⁢

c
initial

⁢
ɛ
⁢

⁢
L

>
0.5

,

where I app defines an applied current density, t + defines a transference number of the electroactive species of the electrolyte, L defines a dimension of the electrochemical cell or electrode, D eff defines an effective diffusivity of the electrolyte, c initial defines the initial concentration of the electrolyte, Q A defines an areal capacity of the electrochemical cell or electrode, and ε defines an electrode porosity.

4. The method of claim 2 , wherein:
the electrochemical cell satisfies

I
app

⁡

(

1
-

t
+

)

⁢
L

F
⁢

⁢

D
eff

⁢

c
initial

+

F
⁢

⁢
v
⁢

⁢

c
initial

⁢
L

<
3

,

where I app defines an applied current density, t + defines a transference number of the electroactive species of the electrolyte, L defines a dimension of the electrochemical cell or electrode, D eff defines an effective diffusivity of the electrolyte, c initial defines the initial concentration of the electrolyte, and v defines the flow velocity.

5. The method of claim 1 , wherein circulating comprises flowing the single electrolyte with an average velocity of greater than or equal to 0.001 μm/s and/or less than or equal to 10,000 μm/s.

6. The method of claim 1 , wherein a thickness of the positive electrode is greater than or equal to 5 μm and/or less than or equal to 5 cm.

7. The method of claim 1 , wherein a thickness of the negative electrode is less than or equal to 5 μm and/or less than or equal to 5 cm.

8. The method of claim 1 , wherein the single electrolyte has an effective diffusivity of greater than or equal to 1×10 −10 cm 2 /s and/or less than or equal to 1×10 −1 cm 2 /s.

9. The method of claim 1 , wherein the electrolyte has an initial electrolyte concentration

Assignees

• Massachusetts Inst Technology

Inventors

• Brushett Fikile Richard
• Gao Weiran
• Drake Javit
• Orella Michael

Classifications

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title