Apparatus for inspecting electrode-tab assembly and inspection method using same

Abstract

According to exemplary embodiments, an apparatus for inspecting an electrode-tab assembly is provided. The apparatus for inspecting an electrode-tab assembly comprises: a first jig configured to retain an electrode including a coated portion and an uncoated portion; a second jig configured to pull an electrode tab welded to the uncoated portion of the electrode in a direction which is not parallel to the electrode; and a gauge configured to detect a tensile force applied to the electrode tab.

Description

Electrode-tab assembly inspection device and inspection method using the same

[0001] The present invention relates to an electrode-tab assembly inspection device and an inspection method using the same. More specifically, the present invention relates to an inspection device configured to measure the weld strength between an electrode tab and an electrode, and an inspection method using the same. This application claims the benefit of Korean Application No. 10-2023-0176700, filed December 7, 2023, which is incorporated herein by reference in its entirety.

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0003] The manufacturing of secondary batteries includes electrode processes, including mixing, coating, roll pressing, slitting, and notching; an assembly process, which embeds the electrode assembly in a case; and an activation process, which electrically activates and stabilizes the battery cells. After the activation process, the battery cells can be stacked to form a cell stack. The cell stack can be mounted in a housing with a module frame, or directly in the housing without a module frame.

[0004] The technical idea of ​​the present invention is to provide an electrode-tab assembly inspection device with improved reliability and an inspection method using the same.

[0005] According to exemplary embodiments of the present invention for solving the above-described problem, an electrode-tab assembly inspection device is provided. The electrode-tab assembly inspection device includes a first jig configured to secure an electrode including a holding portion and a non-conducting portion; a second jig configured to pull an electrode tab welded to the non-conducting portion of the electrode in a direction non-parallel to the electrode; and a gauge configured to detect a tensile force applied to the electrode tab.

[0006] The second jig is configured to pull the electrode tab in an oblique direction to the electrode.

[0007] The second jig is configured to pull the electrode tab in a direction perpendicular to the electrode.

[0008] The first jig is configured to move the electrode so that the angle between the electrode tab and the electrode is constant.

[0009] The above first jig is a rail jig.

[0010] The above electrode-tab assembly inspection device further includes a connecting device connecting the first jig and the second jig.

[0011] The magnitude of the displacement of the above first jig is the same as the magnitude of the displacement of the above second jig.

[0012] According to exemplary embodiments, a method of inspection is provided. The method comprises the steps of applying a tensile force in a non-parallel direction to an electrode-tab assembly including an electrode and an electrode tab, the electrode-tab assembly including a plurality of welds of the electrode and the electrode tab; and determining a fracture energy of the plurality of welds of the electrode and the electrode tab of the electrode-tab assembly.

[0013] The above tensile force is perpendicular to the electrode.

[0014] The above tensile force is oblique to the above electrode.

[0015] The direction of the tensile force is constant while the above plurality of welds are fractured.

[0016] In the step of applying a tensile force that is not parallel to the electrode to the electrode-tab assembly, the electrode is moved in a direction parallel to the electrode.

[0017] The fracture energy of the plurality of welds is calculated based on the integral of the displacement of the jig with respect to the tensile force applied to the electrode-tab assembly, and the jig is configured to fix the electrode tab and move the electrode tab.

[0018] While the above plurality of welds are broken, the jig is moved at a constant speed.

[0019] An electrode-tab assembly inspection device according to exemplary embodiments of the present invention may be configured to apply a tensile force to the electrode-tab assembly in a direction non-parallel to the electrode. Accordingly, the electrode tab can be prevented from breaking before the weld between the electrode and the electrode tab is broken, and the reliability of the electrode-tab assembly inspection device and a method using the same can be improved.

[0020] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0021] Figure 1 is a flowchart for explaining an inspection method according to exemplary embodiments.

[0022] FIG. 2 is a drawing showing an electrode-tab assembly inspection device according to exemplary embodiments.

[0023] Figure 3 is a perspective view showing an electrode-tab assembly.

[0024] Figure 4 is a perspective view showing an electrode-tab assembly.

[0025] Figure 5 is a graph showing the inspection of the electrode-tab assembly.

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0027] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0028] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0029] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0030]

[0031] (Embodiments 1 and 2)

[0032] Figure 1 is a flowchart for explaining an inspection method according to exemplary embodiments.

[0033] FIG. 2 is a drawing showing an electrode-tab assembly inspection device (100) according to exemplary embodiments.

[0034] Figure 3 is a perspective view showing an electrode-tab assembly (ETA).

[0035] Referring to FIGS. 1 to 3, at P110, an electrode-tab assembly (ETA) can be loaded into an electrode-tab assembly inspection device (100).

[0036] An electrode-tab assembly (ETA) may include an electrode (EL) and an electrode tab (ET) coupled to the electrode (EL). The electrode (EL) may be either a positive electrode or a negative electrode. The electrode (EL) may include a current collector and an active material.

[0037] The thickness of the positive electrode current collector may range from about 3 μm to about 500 μm. The positive electrode current collector may not cause chemical changes in the secondary battery to be ultimately manufactured and may have high conductivity. The positive electrode current collector may include, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum. The positive electrode current collector may also include stainless steel surface-treated with carbon, nickel, titanium, silver, or the like. The surface of the positive electrode current collector may include a micro-roughened structure to increase the adhesion of the active material. The positive electrode current collector may have a shape such as a film, a sheet, a foil, a net, a porous material, a foam, or a non-woven fabric.

[0038] The thickness of the negative electrode current collector may be in the range of about 3 μm to about 500 μm. The negative electrode current collector may not cause chemical changes in the secondary battery ultimately manufactured and may have high conductivity. The negative electrode current collector may include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, and an aluminum-cadmium alloy. The negative electrode current collector may also include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the negative electrode current collector may include a micro-roughened structure to increase the adhesion of the active material. The negative electrode current collector may have a shape such as a film, a sheet, a foil, a net, a porous material, a foam, or a non-woven fabric.

[0039] A cathode active material is a material capable of causing an electrochemical reaction. The cathode active material may be a lithium transition metal oxide. Examples of the cathode active material include layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; chemical formula LiNi 1-y M y Lithium nickel oxide expressed as O2 (wherein, M is any one of Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, and Ga, and 0.01≤y≤0.7); Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+zN i 0.4 Mn 0.4 Co 0.2 Li like O2 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e(wherein, -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d<1, M is any one of Al, Mg, Cr, Ti, Si, and Y, and A is any one of F, P, and Cl) Lithium nickel cobalt manganese composite oxide; chemical formula Li 1+x M 1-y M' y PO 4-z X z (wherein, M is a transition metal, more specifically, one of Fe, Mn, Co, and Ni, M' is one of Al, Mg, and Ti, X is one of F, S, and N, -0.5≤x≤+0.5, 0≤y≤0.5, and 0≤z≤0.1) and may include an olivine-based lithium metal phosphate.

[0040] The negative active material may include carbon, such as non-graphitizable carbon, graphitic carbon, etc. The negative active material may include, for example, Li x Fe2O3(0≤x≤1), LixWO2(0≤x≤1), Sn x Me 1-x Me' y O z (wherein Me is any one of Mn, Fe, Pb and Ge, and Me' is any one of Al, B, P, Si, elements of group 1, 2 and 3 of the periodic table and halogens; 0 <x≤1 이고; 1≤y≤3 이며; 1≤z≤8) 등의 금속 복합 산화물을 포함할 수 있다. 음극 활물질은, 예컨대, 리튬 금속; 리튬 합금; 규소계 합금; 주석계 합금을 포함할 수 있다. 음극 활물질은, 예컨대, SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5등의 금속 산화물을 포함할 수 있다. 음극 활물질은, 예컨대, 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni 계 재료 등을 포함할 수 있다.

[0041] The electrode (EL) may include a holding portion (CP), which is a portion to which an active material is applied, and a non-conductive portion (UCP), which is a portion to which an active material is not applied and thus exposes the positive electrode current collector. An electrode tab (ET) may be bonded to the non-conductive portion (UCP) of the electrode (EL). As a non-limiting example, the electrode tab (ET) may be fixed to the electrode (EL) by a method such as ultrasonic welding. The electrode tab (ET) may also be fixed to the electrode (EL) by a method such as resistance welding, laser welding, or arc welding.

[0042] An electrode-tab assembly (ETA) may include a plurality of welds (WP1, WP2, WP3). The plurality of welds (WP1, WP2, WP3) may be arranged sequentially along the extension direction of the electrode tab (ET). The weld (WP3) may be closest to the end of the electrode tab (ET) that contacts the electrode (EL). The weld (WP2) may be interposed between the welds (WP1, WP2).

[0043] An electrode-tab assembly inspection device (100) may be configured to measure the weld strength of an electrode-tab assembly (ETA). The electrode-tab assembly inspection device (100) may include a first jig (110), a second jig (120), a connecting device (130), and a gauge (140).

[0044] Loading the electrode-tab assembly (ETA) into the electrode-tab assembly inspection device (100) may include securing the electrode (EL) to a first jig (110) and securing the electrode tab (ET) to a second jig (120).

[0045] The first jig (110) may be configured to fix the electrode (EL) of the electrode-tab assembly (ETA). The first jig (110) may be a rail jig. The first jig (110) may be configured to move the electrode (EL) of the electrode-tab assembly (ETA). The first jig (110) may be configured to move the electrode (EL) of the electrode-tab assembly (ETA) in a direction parallel to the electrode (EL).

[0046] The first jig (110) may include a rail (111), a jig plate (113), and fixtures (115). The fixtures (115) may be, for example, fixing screws. By tightening the fixtures (115), the jig plate (113) may press the electrode (EL), thereby fixing the electrode (EL) to the jig plate (113). The jig plate (113) may include an electrode tab (ET) and a structure (e.g., a hollow or a slit) that exposes a portion of the electrode (EL) coupled to the electrode tab (ET) (e.g., a portion of the uncoated portion (UCP)). The jig plate (113) may be configured to move along the rail (111). The electrode (EL) may be moved by the movement of the jig plate (113).

[0047] The second jig (120) may include a jig frame (121), a first clamp (123), a second clamp (125), and a regulator (127). The jig frame (121) may support other elements of the second jig (120), such as the first clamp (123), the second clamp (125), and the regulator (127). The first clamp (123) may be fixed to the jig frame (121). The second clamp (125) may face the first clamp (123). The second clamp (125) may be configured to move forward or backward with respect to the first clamp (123) by operation of the regulator (127). The electrode tab (ET) pulled upward (i.e., toward the second jig (120)) through the slit or hollow of the jig plate (113) can be pressed by the second clamp (125) and the first clamp (123), and thus, the electrode tab (ET) can be fixed to the second jig (120). The first and second clamps (123, 125) can include a protruding structure, such as a knurled shape, to securely fix the electrode tab (ET). As a tensile force is applied to the second jig (120) (i.e., as an external force is applied to the second jig (120) to pull the second jig (120), a tensile force can be applied to the electrode-tab assembly (ETA).

[0048] The second jig (120) can be connected to the first jig (110). The second jig (120) can be connected to the first jig (110) by a connecting device (130). The connecting device (130) can include a core (131) and a connecting wire (133). The extension direction of the connecting wire (133) can be changed based on the core (131). The connecting wire (133) between the core (131) and the second jig (120) can be parallel to the tensile direction of the second jig (120) (i.e., the direction in which the electrode tab (ET) is pulled). The connecting wire (133) between the core (131) and the first jig (110) can be parallel to the electrode (EL).

[0049] The gauge (140) may be coupled to the second jig (120). The gauge (140) may be, for example, a push-pull gauge. The gauge (140) may be configured to detect the magnitude of the tensile force applied to the electrode tab (ET).

[0050]

[0051] Figure 4 is a perspective view showing the electrode-tab assembly (ETA) after the weld (WP1, see Figure 3) has been broken.

[0052] Referring to FIGS. 1 to 4, at P120, a tensile force in a direction non-parallel to the electrode (EL) can be applied to the electrode-tab assembly (ETA). The direction non-parallel to the electrode (EL) can include a direction substantially perpendicular to the electrode (EL) and a direction oblique to the electrode (EL). That is, the tensile force applied to the electrode-tab assembly (ETA) can be perpendicular to the electrode (EL) or oblique. By moving the second jig (120) in a direction non-parallel to the electrode (EL) so as to be away from the electrode (EL), a tensile force in a direction non-parallel to the electrode (EL) can be applied to the electrode-tab assembly (ETA).

[0053] According to exemplary embodiments, as a tensile force is applied to the electrode-tab assembly (ETA), a plurality of welded portions (WP1, WP2, WP3) of the electrode (ETA) assembly may be sequentially broken. That is, after the welded portion (WP1) is broken, the welded portion (WP2) may be broken, and after the welded portion (WP2) is broken, the welded portion (WP3) may be broken. According to exemplary embodiments, while the plurality of welded portions (WP1, WP2, WP3) are broken, the second jig (120) may be moved at a constant speed, but is not limited thereto.

[0054] By means of the connecting device (130), movement of the second jig (120) can cause movement of the first jig (110), and the movement distance of the second jig (120) can be substantially the same as the movement distance of the first jig (110). According to exemplary embodiments, by means of the movement of the first jig (110), even after the welded portion (WP1) is broken, the direction of the tensile force applied to the electrode-tab assembly (ETA) can be maintained. Accordingly, the tensile force in the same direction can be applied to the electrode-tab assembly (ETA) while each of the plurality of welded portions (WP1, WP2, WP3) is broken. That is, the direction of the tensile force applied to the electrode-tab assembly (ETA) can be maintained constant while the electrode-tab assembly (ETA) is inspected. Since multiple welds (WP1, WP2, WP3) can be fractured under the same conditions, the strength of the welds of multiple welds (WP1, WP2, WP3) can be accurately compared.

[0055] A person skilled in the art will readily arrive at any embodiment in which the displacements of the first and second jigs (110, 120) are synchronized, such as an embodiment in which the first and second jigs (110, 120) are driven by high-precision motors (e.g., linear servo motors), unlike the connecting device of FIG. 2, so that the displacements of the first and second jigs (110, 120) are the same.

[0056] Furthermore, by applying a tensile force in a direction non-parallel to the electrode (EL) to the electrode-tab assembly (ETA), the tensile force can be concentrated on the plurality of welded portions (WP1, WP2, WP3), and the unwelded portion of the electrode tab (ET) (i.e., the portion spaced apart from the plurality of welded portions (WP1, WP2, WP3)) can be prevented from being broken before the plurality of welded portions (WP1, WP2, WP3) are broken.

[0057]

[0058] Figure 5 is a graph showing the inspection of an electrode-tab assembly (ETA).

[0059] Referring to FIGS. 1 to 5, at P130, the fracture energy of a plurality of welds (WP1, WP2, WP3) can be determined. The gauge (140) can be configured to detect the magnitude of the tensile force applied to the electrode-tab assembly (ETA) and the displacement of the second jig (120) while the plurality of welds (WP1, WP2, WP3) are fractured. The vertical axis of FIG. 5 represents the magnitude of the tensile force applied to the electrode-tab assembly (ETA), and the vertical axis of FIG. 5 represents the displacement of the second jig (120). Accordingly, the fracture energy can be determined through integration of the graph of FIG. 5. In FIG. 5, the vertical axis and the horizontal axis are expressed in arbitrary units.

[0060] In the graph of FIG. 5, the fracture energy of the weld (WP1) can be calculated through integration of the first part (POR1), the fracture energy of the weld (WP2) can be calculated through integration of the second part (POR2), and the fracture energy of the weld (WP3) can be calculated through integration of the third part (POR3).

[0061] The distinction between the first to third portions (POR1, POR2, POR3) may be based on the magnitude of the tensile force applied to the electrode-tab assembly (ETA). For example, when the magnitude of the tensile force falls below a threshold value, it may be determined that the plurality of welded portions (WP1, WP2, WP3) are fractured. Accordingly, the first to third portions (POR1, POR2, POR3) may be matched to the plurality of welded portions (WP1, WP2, WP3) based on the change in the magnitude of the tensile force, and the fracture energy of each of the plurality of welded portions (WP1, WP2, WP3) may be calculated.

[0062]

[0063] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. A first jig configured to fix an electrode including a holding portion and a non-holding portion; A second jig configured to pull the electrode tab welded to the non-parallel portion of the electrode in a direction non-parallel to the electrode; and An electrode-tab assembly inspection device comprising a gauge configured to detect a tensile force applied to the electrode tab.

2. In paragraph 1, An electrode-tab assembly inspection device, characterized in that the second jig is configured to pull the electrode tab in an oblique direction to the electrode.

3. In paragraph 1, An electrode-tab assembly inspection device, characterized in that the second jig is configured to pull the electrode tab in a direction perpendicular to the electrode.

4. In paragraph 1, An electrode-tab assembly inspection device, characterized in that the first jig is configured to move the electrode so that the angle between the electrode tab and the electrode is constant.

5. In paragraph 4, An electrode-tab assembly inspection device, characterized in that the first jig is a rail jig.

6. In paragraph 1, An electrode-tab assembly inspection device further comprising a connecting device connecting the first jig and the second jig.

7. In paragraph 1, An electrode-tab assembly inspection device, characterized in that the size of the displacement of the first jig is the same as the size of the displacement of the second jig.

8. A step of applying a tensile force in a non-parallel direction to an electrode-tab assembly including an electrode and an electrode tab, wherein the electrode-tab assembly includes a plurality of welded portions of the electrode and the electrode tab; and An inspection method comprising the step of determining fracture energy of said plurality of welds of said electrode and said electrode tab of said electrode-tab assembly.

9. In paragraph 8, An inspection method characterized in that the above tensile force is perpendicular to the electrode.

10. In paragraph 8, An inspection method characterized in that the above tensile force is oblique to the electrode.

11. In paragraph 8, An inspection method characterized in that the direction of the tensile force is constant while the plurality of welds are fractured.

12. In paragraph 8, An inspection method characterized in that in the step of applying a tensile force that is not parallel to the electrode to the electrode-tab assembly, the electrode is moved in a direction parallel to the electrode.

13. In paragraph 8, The fracture energy of the above plurality of welds is calculated based on the integral of the displacement of the jig according to the tensile force applied to the electrode-tab assembly, and An inspection method characterized in that the jig is configured to fix the electrode tab and move the electrode tab.

14. In paragraph 13, An inspection method characterized in that the jig is moved at a constant speed while the plurality of welded parts are broken.

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