Three-electrode battery and performance analysis system using the same

Abstract

The present invention relates to a three-electrode battery and a performance analysis system using the same, and provides a three-electrode battery in which electrode denting and internal short circuit phenomena are suppressed, and a performance analysis system using the same.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0182857, filed December 20, 2021, and Korean Patent Application No. 10-2022-0131188, filed October 13, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a three-electrode battery and a performance analysis system using the same, and more particularly to a three-electrode battery in which electrode depression and internal short-circuiting phenomena are suppressed, and a performance analysis system using the same. [Background technology]

[0003] For the separate analysis of the positive and negative electrodes of secondary batteries, a three-electrode analytical system using a reference electrode is mainly used. Conventional three-electrode systems use LTO (Li4Ti5O 12 ) A thin copper wire coated with active material is used as the reference electrode.

[0004] Specifically, as shown in FIG. 1, in a three-electrode battery, a Cu wire coated with an LTO active material is inserted as a reference electrode 14 into a separator 13 laminated between a positive electrode 11 and a negative electrode 12. More specifically, the separator 13 between the positive electrode 11 and the negative electrode 12 may be composed of two layers, and the reference electrode 14 may be located between the two layers of separator 13.

[0005] In this case, when a wire-type reference electrode is used, a blocking area occurs depending on the shape of the reference electrode 14 as shown in FIG. 2, which results in an unreacted area, making it difficult to accurately separate and analyze the positive and negative electrodes.

[0006] The size of the interruption area increases depending on the stiffness and thickness of the electrode itself, which becomes a problem. In particular, as the thickness of the electrode increases and the internal pressure of the battery increases due to gas generation while the battery is in operation, the pressure increases in the area where the reference electrode is located, which can cause damage to the electrode and the separator.

[0007] Therefore, there is a need for a technology for a battery or system that can perform stable three-electrode analysis regardless of the physical properties of the electrodes themselves and how they are driven. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention relates to a three-electrode battery and a performance analysis system using the same, and aims to provide a three-electrode battery in which electrode depression and internal short circuit phenomena are suppressed, and a performance analysis system using the same.

[0009] The technical problems that the present invention aims to solve are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0010] The three-electrode battery of the present invention includes a main separator; a film-like reference electrode laminated on one side of the main separator; an auxiliary separator laminated on the one side of the main separator with the reference electrode sandwiched therebetween; a first electrode and a second electrode laminated with the main separator, the reference electrode, and the auxiliary separator sandwiched therebetween; and a battery case having an internal space in which the main separator, the reference electrode, the auxiliary separator, the first electrode, and the second electrode are accommodated.

[0011] In the three-electrode battery of the present invention, the reference electrode has a plurality of perforations formed therein.

[0012] The performance analysis system of the present invention includes a working electrode connector connected to the first electrode to measure the electrode potential of the first electrode; a counter electrode connector connected to the second electrode; a reference electrode connector connected to the reference electrode; and a measuring unit connected to the working electrode connector, the counter electrode connector, and the reference electrode connector to measure the potential of the first electrode. [Effects of the Invention]

[0013] The three-electrode battery and performance analysis system using the same of the present invention can minimize the size of the blocking area caused by the reference electrode, thereby preventing electrode damage such as electrode dents caused by changes in the internal pressure of the battery and circuit problems such as internal short circuits.

[0014] The three-electrode battery and the performance analysis system using the same of the present invention are capable of separate analysis of the positive and negative electrodes with high reliability, regardless of the physical properties and driving conditions of the electrodes themselves.

[0015] The three-electrode battery of the present invention is advantageous for analyzing Si / SiO batteries, which have large thickness variations, and for long-term degradation analysis.

[0016] The three-electrode battery of the present invention is expected to have the effect of reducing the deviation of the three electrodes due to the reduction in the blocking area.

[0017] The three-electrode battery of the present invention has a structure that is easy to design for medium- to large-sized batteries and is applicable regardless of the electrode stack or area. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a conceptual diagram showing a conventional three-electrode battery. [Figure 2] FIG. 1 is a cross-sectional view showing a conventional three-electrode battery. [Figure 3] FIG. 1 is a cross-sectional view showing a three-electrode battery of the present invention. [Figure 4]FIG. 1 is an exploded perspective view showing the stacked structure of a three-electrode battery of the present invention. [Figure 5] FIG. 3 is a plan view showing the positional relationship between a first electrode and a reference electrode. [Figure 6] 10 is a graph showing battery characteristics depending on the porosity of the first region. [Figure 7A] Photographs showing the state of the battery electrodes relative to the reference electrode. [Figure 7B] Photographs showing the state of the battery electrodes relative to the reference electrode. [Figure 7C] Photographs showing the state of the battery electrodes relative to the reference electrode. [Figure 8] 10 is a graph showing the depth of charge at 1C charge and 2C charge. DETAILED DESCRIPTION OF THE INVENTION

[0019] The three-electrode battery of the present invention includes a main separator; a film-like reference electrode laminated on one side of the main separator; an auxiliary separator laminated on the one side of the main separator with the reference electrode sandwiched therebetween; a first electrode and a second electrode laminated with the main separator, the reference electrode, and the auxiliary separator sandwiched therebetween; and a battery case having an internal space in which the main separator, the reference electrode, the auxiliary separator, the first electrode, and the second electrode are accommodated.

[0020] In the three-electrode battery of the present invention, the reference electrode has a plurality of perforations formed therein.

[0021] In the three-electrode battery of the present invention, the reference electrode includes a first region facing the first electrode or the second electrode and a second region protruding from one side of the first electrode or the second electrode, and the plurality of perforations are formed in the first region.

[0022] The three-electrode battery of the present invention further includes a reference electrode lead having one end fused to the second region of the reference electrode and the other end protruding outside the battery case.

[0023] In the three-electrode battery of the present invention, the first electrode or the second electrode has a rectangular shape with edges in a first direction and a second direction that are perpendicular to each other, and when the length of the first electrode or the second electrode in the first direction is longer than the length in the second direction, the length of the first region in the first direction is 1 to 3% of the length of the first electrode or the second electrode in the first direction, and the length of the first region in the second direction is 5 to 95% of the length of the first electrode or the second electrode in the second direction.

[0024] In the three-electrode battery of the present invention, the reference electrode includes a foil member forming a body and a reference electrode active material coated on the foil member.

[0025] In the three-electrode battery of the present invention, the material of the foil member includes one or more of Cu-foil and Al-foil.

[0026] In the three-electrode battery of the present invention, the reference electrode active material is LTO (Li4Ti5O 12 ), LFP (LiFePO4), Li metal, and combinations thereof.

[0027] The performance analysis system of the present invention includes a working electrode connecting part connected to the first electrode in order to measure the electrode potential of the first electrode; a counter electrode connecting part connected to the second electrode; a reference electrode connecting part connected to the reference electrode; and a measuring part connected to the working electrode connecting part, the counter electrode connecting part, and the reference electrode connecting part, and for measuring the potential of the first electrode.

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, the size and shape of components shown in the drawings may be exaggerated for clarity and convenience. Furthermore, terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intentions or practices of users and operators. Definitions of such terms should be based on the overall content of this specification.

[0029] In describing the present invention, it should be noted that the orientations or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "one side," and "other side" are based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships in which the product of the present invention is normally arranged when in use, and are merely for the purpose of explaining and simplifying the present invention. They do not present or imply that the displayed devices or elements must necessarily be configured or operated in a specific orientation, and should not be understood as limiting the present invention.

[0030] FIG. 3 is a cross-sectional view showing a three-electrode battery of the present invention. FIG. 4 is an exploded perspective view showing the stacked structure of a three-electrode battery of the present invention. FIG. 5 is a plan view showing the relative positions of the first electrode 140 and the reference electrode 110. FIG. 6 is a graph showing battery characteristics depending on the porosity of the first region A1. FIGS. 7A to 7C are photographs showing the state of the battery electrodes using the reference electrode 110. FIG. 8 is a graph showing the depth of charge at 1C charge and 2C charge.

[0031] The three-electrode battery of the present invention will be described in detail below with reference to Figures 3 to 8. In the xyz coordinate system shown in Figures 3 to 5, the x-axis direction is the first direction, the y-axis direction is the second direction, and the z-axis direction is the up-down direction.

[0032] The three-electrode battery of the present invention is applicable to various types of batteries, but is optimized for pouch-type batteries.

[0033] As shown in FIG. 3, the three-electrode battery of the present invention includes a main separator 120; a film-shaped reference electrode 110 laminated on one side of the main separator 120; an auxiliary separator 130 laminated on one side of the main separator 120 with the reference electrode 110 sandwiched therebetween; a first electrode 140 and a second electrode 150 laminated with the main separator 120, the reference electrode 110, and the auxiliary separator 130 sandwiched therebetween; and a battery case 160 in which the main separator 120, the reference electrode 110, the auxiliary separator 130, the first electrode 140, and the second electrode 150 are accommodated.

[0034] One of the first electrode 140 and the second electrode 150 may be formed as a positive electrode, and the other may be formed as a negative electrode.

[0035] As shown in FIGS. 3 and 4, the first electrode 140 may include a first electrode collector 141, a first electrode active material 142 coated on the surface of the first electrode collector 141, a first electrode tab 144 welded to an uncoated portion of the first electrode collector 141 where the first electrode active material 142 is not coated, and a first electrode lead 145 having one end welded to the first electrode tab 144 inside the battery case 160 and the other end protruding outside the battery case 160. The second electrode 150 may also include a second electrode collector 151, a second electrode active material 152 coated on the surface of the second electrode collector 151, a second electrode tab 154 welded to an uncoated portion of the second electrode collector 151 where the second electrode active material 152 is not coated, and a second electrode lead 155 having one end welded to the second electrode tab 154 inside the battery case 160 and the other end protruding outside the battery case 160.

[0036] The material of the main separator 120 and the auxiliary separator 130 includes at least one of ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer.

[0037] The main separator 120 is located between the first electrode 140 and the second electrode 150 .

[0038] A plurality of main separators 120, first electrodes 140 and second electrodes 150 may be provided, and in this case, the auxiliary separator 130 and the reference electrode 110 may be provided on one of the plurality of main separators 120.

[0039] The main separator 120, the first electrode 140, and the second electrode 150 are each formed in a sheet shape and are stacked so as to cross each other.

[0040] The auxiliary separator 130 may be formed to a size that can cover the reference electrode 110 so that the reference electrode 110 does not directly contact the first electrode 140 or the second electrode 150 .

[0041] As shown in FIG. 4, the three-electrode battery of the present invention is completed by injecting an electrolyte into a battery case 160 together with an electrode assembly formed by stacking a first electrode 140, a main separator 120, a reference electrode 110, an auxiliary separator 130, and a second electrode 150 in this order, or by stacking the first electrode 140, the auxiliary separator 130, the reference electrode 110, the main separator 120, and a second electrode 150 in this order, and then sealing the battery case 160.

[0042] In this case, when a plurality of first electrodes 140 and a plurality of second electrodes 150 are provided, the first electrode tabs 144 welded to each of the plurality of first electrodes 140 are welded to one first electrode lead 145, and the second electrode tabs 154 welded to each of the plurality of second electrodes 150 are welded to one second electrode lead 155, and one end of the first electrode lead 145 and one end of the second electrode lead 155 protrude outside the battery case 160.

[0043] In the three-electrode battery of the present invention, the reference electrode 110 has a plurality of perforation holes 113 formed therein. By forming a plurality of perforation holes 113 in the reference electrode 110, the reference electrode 110 can be prevented from interfering with the movement of ions between the first electrode 140 and the second electrode 150, and the formation of a blocking region can be suppressed.

[0044] 3 and 5, the reference electrode 110 includes a first region (A1) facing the first electrode 140 or the second electrode 150, and a second region (A2) protruding from one side of the first electrode 140 or the second electrode 150, and the plurality of perforation holes 113 are formed in the first region (A1). That is, the first region (A1) serves as a reference for the potential applied to the first electrode 140 or the second electrode 150, and the second region (A2) is for electrical connection.

[0045] The total area of ​​the plurality of punch holes 113 may be 30 to 70% of the area of ​​the first region (A1). That is, the total area of ​​the plurality of punch holes 113 may be 30 to 70% of the area of ​​the first region (A1). If the porosity in the first region (A1) is 30% or less, ion diffusion is difficult, and if it is 70% or more, there is a problem of the reference electrode being broken. Therefore, it is preferable that the porosity of the plurality of punch holes 113 formed in the first region (A1) is 30 to 70%.

[0046] FIG. 6 is a graph showing battery characteristics as a function of the porosity of the first region. Specifically, for a battery including an electrode assembly in which a positive electrode, a separator, and a negative electrode are stacked in this order, a test foil with perforations was inserted between the separator and the negative electrode, and the graph shows battery characteristics as a function of the porosity (open ratio) of the test foil. Four batteries were prepared, and test foils with porosities of 17%, 32%, and 50% were inserted into three batteries, respectively, while no test foil was inserted into the remaining battery. As shown in FIG. 7, the battery equipped with a test foil with a porosity of less than 30% (17% porosity) exhibited impaired ion migration, while the batteries equipped with test foils with porosities of 30% or more (32% and 50% porosity) exhibited behavior similar to that of a secondary battery without a test foil.

[0047] The three-electrode battery of the present invention further includes a reference electrode lead 115, one end of which is fused to the second region (A2) of the reference electrode 110 and the other end of which protrudes outside the battery case 160. Because the reference electrode 110 is formed of a thin metal film or foil, it does not have the minimum rigidity required for fusion to seal the battery case 160 or for connection to an external electrical terminal. Therefore, the reference electrode lead 115, which is a conductor for electrical connection, is connected to the reference electrode 110, and the reference electrode lead 115 is welded to the second region (A2).

[0048] The reference electrode 110 is provided to have a thickness of 45 to 120 μm. The thickness of the reference electrode 110 is determined in consideration of the lifting phenomenon between the first electrode 140 and the second electrode 150, and the dent phenomenon due to impact or vibration applied to the three-electrode battery itself.

[0049] 5, in the three-electrode battery of the present invention, the first electrode 140 or the second electrode 150 has a rectangular shape with edges in a first direction and a second direction that are perpendicular to each other. More specifically, the length of the first electrode 140 or the second electrode 150 in the first direction may be longer than the length of the second direction.

[0050] In this case, the length Wr of the first region (A1) in the first direction is formed to be 1 to 3% of the length FL of the first electrode 140 or the second electrode 150 in the first direction, and the length Lr of the first region (A1) in the second direction is formed to be 5 to 95% of the length Fw of the first electrode 140 or the second electrode 150 in the second direction. The length Lr of the first region (A1) in the second direction is determined in consideration of the specifications, material, number of layers, layer configuration, etc. of the first electrode or the second electrode.

[0051] That is, the reference electrode 110 has a shape that extends in a direction perpendicular to the longitudinal direction of the first electrode 140 or the second electrode 150.

[0052] 1, the reference electrode 110 includes a foil member 111 forming a body and a reference electrode active material 112 coated on the foil member 111. The reference electrode active material 112 may be applied to a first region (A1), and the second region (A2) may be a plain region where the reference electrode active material 112 is not applied. For example, the width of the first region (A1) and the second region (A2) in the first direction may be 2 mm, and the length of the first region (A1) in the second direction may be 15 mm, and the length of the second region (A2) may be 3 mm.

[0053] The material of the foil member 111 includes one or more of Cu-foil and Al-foil, and the reference electrode active material 112 is LTO (Li4Ti5O 12 ), LFP (LiFePO4), Li metal, and combinations thereof.

[0054] The performance analysis system using the three-electrode battery of the present invention includes a working electrode connector connected to the first electrode 140 to measure the electrode potential of the first electrode 140; a counter electrode connector connected to the second electrode 150; a reference electrode connector connected to the reference electrode 110; and a measuring unit connected to the working electrode connector, the counter electrode connector, and the reference electrode connector to measure the potential of the first electrode 140.

[0055] The first electrode 140 may be either a positive electrode or a negative electrode depending on the purpose of the analysis.

[0056] 7A to 7C are photographs of the electrode surfaces of a three-electrode battery using the reference electrode 110 of the present invention and a conventional wire-type reference electrode. In Figures 7A to 7C, the left side shows the battery using the conventional wire-type reference electrode, and the right side shows the battery using the reference electrode 110 of the present invention.

[0057] Figure 7A is a photograph of an electrode extracted from a battery with a state of charge (SoC) of 100%. While unreacted regions are observed in the conventional type, no unreacted regions are observed in the electrodes of the three-electrode battery of the present invention.

[0058] Figure 7B shows a photograph of an electrode extracted from a battery that had been subjected to 20 1C / 1C charge-discharge cycles. The conventional type exhibits uneven Li deposition near the wire reference electrode.

[0059] 7C is a photograph of an electrode extracted from a battery that has undergone fast charging. While conventional types exhibit deepening of precipitation in the area adjacent to the wire-type reference electrode, the electrodes of the three-electrode battery of the present invention show less precipitation in the area adjacent to the reference electrode 110.

[0060] 8 is a graph showing the depth of charge at 1 C charge and 2 C charge. It can be seen that the three-electrode battery of the present invention has a smaller deviation in depth of charge than the conventional battery.

[0061] While the embodiments of the present invention have been described above, they are merely illustrative, and those skilled in the art will recognize that various modifications and equivalent embodiments are possible. Therefore, the true technical scope of the present invention should be determined by the following claims. [Industrial Applicability]

[0062] The three-electrode battery and performance analysis system using the same of the present invention can minimize the size of the blocking area caused by the reference electrode, thereby preventing electrode damage such as electrode dents caused by changes in the internal pressure of the battery and circuit problems such as internal short circuits.

[0063] The three-electrode battery and the performance analysis system using the same of the present invention are capable of separate analysis of the positive and negative electrodes with high reliability, regardless of the physical properties and driving conditions of the electrodes themselves.

[0064] The three-electrode battery of the present invention is advantageous for analyzing Si / SiO batteries, which have large thickness variations, and for long-term degradation analysis.

[0065] The three-electrode battery of the present invention is expected to have the effect of reducing the deviation of the three electrodes due to the reduction in the blocking area.

[0066] The three-electrode battery of the present invention has a structure that is easy to design for medium- to large-sized batteries and is applicable regardless of the electrode stack or area. [Explanation of symbols]

[0067] 110:Reference electrode 111: Foil material 112: Reference electrode active material 113: Hole punching 115: Reference electrode lead 120: Main separation membrane 130:Auxiliary separation membrane 140: 1st electrode 141: First electrode current collector 142:First electrode active material 144: First electrode tab 145: First electrode lead 150: 2nd electrode 151: Second electrode current collector 152: Second electrode active material 154: Second electrode tab 155: Second electrode lead 160: Battery case A1:First area A2:Second area

Claims

1. A main separation membrane; a film-type reference electrode laminated on one side of the main separator; an auxiliary separator laminated on the one side of the main separator with the reference electrode interposed therebetween; a first electrode and a second electrode stacked on each other with the main separator, the reference electrode, and the auxiliary separator sandwiched therebetween; a battery case having an internal space in which the main separator, the reference electrode, the auxiliary separator, the first electrode, and the second electrode are accommodated; Including, The reference electrode is a first region facing the first electrode or the second electrode; a second region protruding from one side of the first electrode or the second electrode, A plurality of punch holes are formed in the first region; the first electrode or the second electrode has a rectangular shape with edges in a first direction and a second direction that are orthogonal to each other, When the length of the first electrode or the second electrode in the first direction is longer than the length of the second electrode in the second direction, a length of the first region in the first direction is formed to be 1 to 3% of a length of the first electrode or the second electrode in the first direction; the length of the first region in the second direction is 5 to 95% of the length of the first electrode or the second electrode in the second direction; 3 electrode battery.

2. 2. The three-electrode battery according to claim 1, further comprising a reference electrode lead having one end fused to the second region of the reference electrode and the other end protruding outside the battery case.

3. The total area of ​​the plurality of punching holes is 30 to 70% of the area of ​​the first region, The three-electrode battery of claim 1 .

4. The reference electrode is a foil member forming a fuselage; a reference electrode active material coated on said foil member.

5. 5. The three-electrode battery according to claim 4, wherein the material of the foil member includes one or more of Cu-foil and Al-foil.

6. The reference electrode active material is LTO (Li ４ Ti ５ O １２ ), LFP (LiFePO ４ 5. The three-electrode battery of claim 4, wherein the anion is selected from the group consisting of: ZnO, Li metal, Li metal, and combinations thereof.

7. A performance analysis system using a three-electrode battery, The three-electrode battery is A main separation membrane; a film-type reference electrode laminated on one side of the main separator; an auxiliary separator laminated on the one side of the main separator with the reference electrode interposed therebetween; a first electrode and a second electrode stacked on each other with the main separator, the reference electrode, and the auxiliary separator sandwiched therebetween; a battery case having an internal space in which the main separator, the reference electrode, the auxiliary separator, the first electrode, and the second electrode are accommodated; Including, The reference electrode is a first region facing the first electrode or the second electrode; a second region protruding from one side of the first electrode or the second electrode, A plurality of punch holes are formed in the first region; a total area of ​​the plurality of punching holes is 30 to 70% of an area of ​​the first region; The performance analysis system includes: a working electrode connector connected to the first electrode for measuring the electrode potential of the first electrode; a counter electrode connector connected to the second electrode; a reference electrode connector connected to the reference electrode; a measuring unit connected to the working electrode connector, the counter electrode connector, and the reference electrode connector, for measuring the potential of the first electrode; A performance analysis system, including:

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