Method and apparatus for evaluating movement tendency of ions in electrolyte membrane

Patent metadata

Field	Value
Publication number	US-10840526-B2
Application number	US-201816197183-A
Country	US
Kind code	B2
Filing date	Nov 20, 2018
Priority date	Jul 30, 2018
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A method of evaluating a movement tendency of ions in an electrolyte membrane includes counting inter-movement ions, counting intra-movement ions and calculating the ratio of the intra-movement ions and inter-movement of ions. The movement tendency of ions is predicted based on the ratio. In the case of evaluating a movement tendency of ions using the method, since the structure of the electrolyte membrane in which the ratios of intra-movement and inter-movement are maximized is predicted through measurement of the ratios of the intra-movement and inter-movement of ions, ohmic resistance that may occur in a membrane-electrode assembly (MEA) may be reduced. The electrolyte membrane having the optimal structure predicted by the method can be applied to a fuel cell to increase its performance.

First claim

What is claimed is:

1. A method of evaluating a movement tendency of ions in an electrolyte membrane, the method comprising:
collecting an identification number (N P1 ) given to a first polymer (P1) including a first target atom (A1), if condition 1 is satisfied and one of condition 2a and condition 2b is also satisfied:
(condition 1) at the time of T 1 , a distance (d T1 ) between the first target atom (A1) which is electrically charged and present on a skeleton of the first polymer (P1) forming an electrolyte membrane and a counterpart ion (I) which has electric charges opposite to the target atom and present outside the polymer is within a predetermined reference distance (d s ),
(condition 2a) at the time of T 1 +Δt1, a distance (d T1+Δt1 ) between the first target atom (A1) and the counterpart ion (I) exceeds the reference distance (d s ) and is within a predetermined cutoff distance (d c ),
(condition 2b) at the time of T 1 +Δt1, both the distance (d T1+Δt1 ) between the first target atom (A1) and the counterpart ion (I) and the distance (d T1+Δt1 ) between a second target atom (A2) which is electrically charged and present on a skeleton of the second polymer (P2) forming the electrolyte membrane and the counterpart ion (I) are within the reference distance (d s );

collecting an identification number (N P2 ) given to the second polymer P2 including a second target atom A2, if condition 3a or condition 3b is satisfied, and condition 4 is also satisfied:
(condition 3a) from the time of T 1 +Δt1 to the time of T 2 , a distance (d T2 ) between the first target atom (A1) and the counterpart ion (I) exceeds the reference distance (d s ) and is present within the predetermined cutoff distance (d c ),
(condition 3b) from the time of T 1 +Δt1 to the time of T 2 , both the distance (d T2 ) between the first target atom (A1) and the counterpart ion (I) and the distance (d T2 ) between the second target atom (A2) and the counterpart ion (I) are present within the reference distance (d s ),
(condition 4) at the time of T 2 +Δt2, a distance (d T2+Δt2 ) between the second target atom (A2) and the counterpart ion (I) is present within the reference distance (d s );

determining whether the identification number (N P1 ) of the first polymer (P1) and the identification number (N P2 ) of the second polymer (P2) are the same; and
counting the number of the counterpart ions (I) when the identification number (N P1 ) and the identification number (N P2 ) are different or counting the number of the counterpart ions (I) when the identification number (N P1 ) and the identification number (N P2 ) are the same.

2. The method according to claim 1 , wherein Δt1 and Δt2 are 0.1 to 500 picoseconds.

3. The method according to claim 1 , wherein the first polymer P1 and the second polymer P2 each include a fluororesin or a hydrocarbon resin terminated with a negative charge function group containing the first target atom A1 and a negative charge function group containing the second target atom A2.

4. The method according to claim 3 , wherein the fluororesin includes a copolymer including repeat units derived from tetrafluoroethylene and repeat units derived from perfluorinated vinyl ether.

5. The method according to claim 3 , wherein the hydrocarbon resin includes any one selected from the group consisting of a polystyrene-based resin, a polyarylene ether-based resin, and a polypenylene-based resin.

6. The method according to claim 3 , wherein the negative charge function group containing the first target atom A1 and the negative charge function group containing the second target atom A2 each are a sulfonic acid group containing a sulfur atom.

7. The method according to claim 1 , wherein the counterpart ion I is a hydronium ion.

8. The method according to claim 1 , wherein the distance (d T1 ), the distance (d T1+Δt1 ), the distance (d T2 ), and the distance (d T2+Δt2 ) are calculated through position information of the target atom and the counterpart ion in the time frame of T 1 , T 1 +Δt1, T 2 , and T 2 +Δt2 using a molecular dynamics simulation.

9. The method according to claim 1 , wherein the reference distance (d s ) is the sum of a van der Waals distance between the target atom A and the counterpart ion I and a vibration distance of each of the target atom A and the counterpart ion I.

10. The method according to claim 1 , wherein the cutoff distance (d c ) is a distance between the target atom and another homogeneous atom which has the same electric charges as those of the target atom and is present.

11. The method according to claim 1 , further comprising:
calculating the sum of the numbers of counterpart ions (I) in case where the identification number N P1 and the identification number N P2 are different as a result of a movement tendency between polymers.

12. The method according to claim 1 , further comprising:
calculating the sum of the numbers of counterpart ions (I) in case where the identification number N P1 and the identification number N P2 are the same as a result of a movement tendency in a polymer.

13. The method according to claim 11 , wherein, in the calculation, a value having a valid ion movement tendency is calculated by dividing the sum of the counterpart ions I in case where the identification number N P1 and the identification number N P2 are different by the number of the counterpart ions I in case where the identification number N P1 and the identification number N P2 are different and the number of counterpart ions I in case where the identification number N P1 and the identification number N P2 are the same.

14. The method according to claim 12 , wherein, in the calculation, a value having a valid ion movement tendency is calculated by dividing the sum of the counterpart ions I in case where the identification number N P1 and the identification number N P2 are the same by the number of the counterpart ions I in case where the identification number N P1 and the identification number N P2 are different and the number of counterpart ions I in case where the identification number N P1 and the identification number N P2 are the same.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Cha Jin Hyeok
• Yun Suk Hwan
• Hong Woong Pyo
• Shim Sun Bo

Classifications

• C08J5/2268

  based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds, and by reactions not involving this type of bond · CPC title

• H01M8/1067

  characterised by their physical properties, e.g. porosity, ionic conductivity or thickness · CPC title

• G01N30/96

  using ion-exchange (G01N30/02, G01N30/90 take precedence) · CPC title

• G01N27/333 Primary

  Ion-selective electrodes or membranes (glass electrodes G01N27/36) · CPC title

• C08J5/2237

  containing fluorine · CPC title