Apparatus for inspecting electrode for secondary battery

Abstract

An apparatus for inspecting an electrode for a secondary battery, according to one embodiment of the present invention, comprises a front surface inspector including: a front inspection camera for inspecting a front surface of an electrode; and a side illumination that irradiates light onto the front surface of the electrode at a predetermined angle with respect to the front inspection camera. In one embodiment of the present invention, the front inspection camera may be a contact image sensor (CIS) camera, and a single camera may simultaneously perform inspection of a notched tab and width and surface inspection of the electrode.

Description

Secondary battery electrode inspection device

[0001] The present invention relates to an electrode inspection device for a secondary battery, and more specifically, to an inspection device for inspecting an electrode used in a secondary battery.

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries refer to batteries capable of charging and discharging, and are applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven by electric power sources.

[0003] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, or unit battery cells, is approximately 2.5V to 4.6V. Therefore, if a higher output voltage is required, a battery pack is formed by connecting multiple battery cells in series. Additionally, a battery pack is formed by connecting multiple battery cells in parallel depending on the charge / discharge capacity required for the battery pack. Accordingly, the number of battery cells included in the battery pack can be varied depending on the required output voltage or charge / discharge capacity.

[0004] When configuring a battery pack by connecting multiple battery cells in series or parallel, it is common practice to first configure a battery module consisting of at least one battery cell, preferably multiple battery cells, and then use at least one such battery module and add other components to form a battery pack. Here, a battery module refers to a component in which multiple battery cells are connected in series or parallel, and a battery pack may refer to a component in which multiple battery modules are connected in series or parallel to increase capacity and output.

[0005] Battery cells are classified into pouch type, cylindrical type, prismatic type, etc., depending on the shape of the battery case.

[0006] Among these, cylindrical cells offer excellent safety as they primarily utilize a metal case with a cylindrical structure. They also have the advantage of high energy density by housing a jelly-roll type electrode assembly inside the case, and make it easy to configure a large-capacity power storage device by connecting multiple cells in series or parallel.

[0007] The electrode assembly, housed in a cylindrical case, is a rechargeable power generation device composed of a stacked structure of an anode, a separator, and a cathode, and is classified into jellyroll, stack, and stack / folding types. The jellyroll type is formed by winding a separator between long sheet-shaped anodes and cathodes coated with active material; the stack type is formed by sequentially stacking multiple anodes and cathodes of a predetermined size with a separator in between; and the stack / folding type is a composite structure of the jellyroll and stack types. Among these, the jellyroll electrode assembly has the advantages of being easy to manufacture and having a high energy density per unit weight.

[0008] The jelly roll electrode assembly is in the form of a wound structure with a separator interposed between an anode and a cathode, each coated with an active material, and an anode tab protruding from the upper part of the electrode assembly is disposed on the anode, and a cathode tab protruding from the lower part of the electrode assembly can be disposed on the cathode.

[0009] During the manufacturing process of these electrode assemblies, four cameras are used per winder to inspect both the positive and negative sides, and two cameras are used per winder to inspect the notching tab after notching. Therefore, a total of six cameras are used per winder to inspect products in the form of individual electrodes; however, conventional cameras require a large inspection space due to optical system characteristics that have a long working distance (the distance from the camera lens to the object being inspected).

[0010] The present invention aims to solve the problems described above and provides an electrode inspection device for a secondary battery capable of inspecting electrodes with a small number of cameras.

[0011] An electrode inspection device for a secondary battery according to one embodiment of the present invention includes an electrode front inspection device comprising: a front inspection camera for inspecting the front surface of an electrode; and a side illumination device that irradiates light onto the front surface of the electrode at a certain angle with respect to the front inspection camera.

[0012] In addition, the above-mentioned front inspection camera may be a Contact Image Sensor (CIS) camera.

[0013] In addition, the angle formed by the front inspection camera with the electrode may be 50 to 70 degrees.

[0014] In addition, the angle formed by the side lighting with the front inspection camera may be 40 to 50 degrees.

[0015] In addition, the electrode front inspection device further includes a backlight that irradiates light onto the rear surface of the electrode.

[0016] In addition, the illumination direction of the above rear light can be aligned with the front inspection camera.

[0017] In addition, the electrode front inspection device further includes two rollers that guide the movement of the electrode.

[0018] In addition, an electrode inspection device for a secondary battery according to one embodiment of the present invention further includes an electrode rear inspection device comprising: a rear inspection camera for inspecting the rear surface of the electrode; and a side illumination device that irradiates light onto the rear surface of the electrode at a certain angle with respect to the rear inspection camera.

[0019] In addition, the above rear inspection camera may be a CIS camera.

[0020] In addition, the angle formed by the rear inspection camera with the electrode may be 30 to 60 degrees.

[0021] In addition, the angle formed by the side illumination of the electrode rear inspection device with the rear inspection camera may be 80 to 100 degrees.

[0022] In addition, the electrode back inspection device further includes two rollers that guide the movement of the electrode.

[0023] An electrode inspection device for a secondary battery according to one embodiment of the present invention can inspect electrodes with a small number of cameras and can reduce the inspection space.

[0024] In one embodiment of the present invention, notching tab and width / surface inspection can be performed simultaneously with a single camera.

[0025] FIG. 1 is a drawing illustrating a cylindrical battery cell in one embodiment of the present invention, and

[0026] FIG. 2 is a drawing showing a cross-sectional view of a cylindrical battery cell in one embodiment of the present invention, and

[0027] FIG. 3 is a drawing illustrating an electrode assembly in an embodiment of the present invention, and

[0028] FIG. 4 is a drawing illustrating the appearance of an electrode assembly before it is wound in an embodiment of the present invention, and

[0029] FIG. 5 is a drawing for explaining the wound form of an electrode assembly in one embodiment of the present invention, and

[0030] FIG. 6 is a diagram illustrating the configuration of an inspection device for inspecting the front surface of an electrode in an electrode inspection device in an embodiment of the present invention, and

[0031] FIG. 7 is a diagram illustrating the configuration of an inspection device for inspecting the rear surface of an electrode in an electrode inspection device in an embodiment of the present invention, and

[0032] Figure 8 is an anode test inspection image acquired with a conventional inspection device, and

[0033] FIG. 9 is an anode test inspection image acquired by an electrode inspection device according to an embodiment of the present invention, and

[0034] FIG. 10 is a perspective view of a battery pack in one embodiment of the present invention, and

[0035] FIG. 11 is a perspective view of an electric vehicle equipped with a battery pack in one embodiment of the present invention.

[0036] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques are not specifically described to avoid the present invention being interpreted ambiguously. Throughout the specification, like reference numerals refer to like components.

[0037] In drawings, thicknesses may be enlarged to clearly represent multiple layers and regions. Throughout the specification, the same reference numerals are used for similar parts. When a part such as a layer, film, region, or plate is described as being "above" another part, this includes not only cases where it is "immediately above" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately above" another part, it means that there is no other part in between. Furthermore, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only cases where it is "immediately below" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately below" another part, it means that there is no other part in between.

[0038] Before describing the electrode inspection device (1000) for a secondary battery according to one embodiment of the present invention, the battery cell (100) is described first.

[0039] FIG. 1 is a drawing illustrating a cylindrical battery cell in an embodiment of the present invention, FIG. 2 is a drawing showing a cross-sectional view of a cylindrical battery cell in an embodiment of the present invention, FIG. 3 is a drawing illustrating an electrode assembly in an embodiment of the present invention, FIG. 4 is a drawing illustrating the appearance of an electrode assembly before it is wound in an embodiment of the present invention, and FIG. 5 is a drawing for explaining the wound form of an electrode assembly in an embodiment of the present invention.

[0040] The battery cell (100) may be a cylindrical battery cell (100) in which an electrode assembly (110) is embedded in a cylindrical can.

[0041] A cylindrical battery cell (100) may include a jelly roll-shaped electrode assembly (110) and a battery case (120) for accommodating the electrode assembly (110), and an upper insulating member (150) may be disposed on the top of the electrode assembly (110), and a lower insulating member (160) may be disposed on the bottom of the electrode assembly (110).

[0042] The electrode assembly (110) has a jelly roll-shaped structure with a first electrode (111), a second electrode (113), and a separator (112) interposed between them, and a center pin (140) can be inserted in the center thereof.

[0043] A cylindrical battery cell (100) can be formed by housing an electrode assembly (110) in a battery case (120), injecting an electrolyte into the battery case (120), and then attaching a cap assembly (130) to the top of the battery case (120). The battery case (120) is cylindrical, and a jelly-roll type electrode assembly (110) can be housed in the cylindrical battery case (120) to realize a cylindrical secondary battery.

[0044] The battery case (120) may include a beading portion (122) and a crimping portion (123).

[0045] The above beading portion (122) is for stable coupling of the cap assembly (130) and can be formed along the circumferential direction on the upper outer surface of the battery case (120), or can be formed by being concavely recessed from the outer surface of the battery case (120) toward the center of the electrode assembly (110). The beading portion (122) can prevent movement of the electrode assembly (110).

[0046] The crimping portion (123) may be positioned on the upper part of the beading portion (122) and formed to wrap around the edge portion of the cap assembly (130) along the circumferential direction. The crimping portion (123) can facilitate a stable connection of the cap assembly (130).

[0047] The cap assembly (130) may include an upper cap (131) forming an electrode terminal, a cap plate (132), and a gasket (133) for airtightness.

[0048] The top cap (131) can form a positive terminal.

[0049] The gasket (133) is mounted on the upper inner surface of the crimping portion (123) and the beading portion (122) to increase the sealing force between the cap assembly (130) and the battery case (120).

[0050] The second electrode tab (111c) may extend upward from the electrode assembly (110). Specifically, it may extend from the second electrode (111) of the electrode assembly (110). The second electrode tab (111c) may be an anode tab.

[0051] This second electrode tab (111c) is connected to the cap plate (132), so that the upper cap (131) can function as an electrode terminal (positive terminal). An opening (151) is formed in the upper insulating member (150), and the second electrode tab (111c) can be connected to the cap plate (132) through the opening (151).

[0052] The center pin (140) generally comprises a metal material to provide a certain strength and is formed as a cylindrical structure formed by bending a plate into a round shape. In addition to self-heating, this center pin (140) can function as a passage to fix and support the electrode assembly (110) and to release gas generated by internal reactions during charging, discharging, and operation.

[0053] The electrolyte injected into the battery case (120) may be a lithium salt-containing non-aqueous electrolyte, and the lithium salt-containing non-aqueous electrolyte is composed of a non-aqueous electrolyte and a lithium salt. Non-aqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, etc. are used as non-aqueous electrolytes, but are not limited to these.

[0054] The battery cell (100) is not necessarily provided as a cylindrical battery cell (100), and may be provided as a battery cell of other shapes, such as a rectangular battery cell.

[0055] FIG. 4 is a drawing showing the appearance of the electrode assembly (110) before it is wound. The electrode assembly (110) can be formed into a jelly roll shape by winding together a long sheet-shaped first electrode (113), a second electrode (111), and a separator (112). The separator (112) can be interposed between the first electrode (113) and the second electrode (111). Additionally, the separator (112) can be additionally placed under the second electrode (111) to prevent the first electrode (113) and the second electrode (111) from coming into contact when wound into a jelly roll shape.

[0056] The first electrode (113) may include a first electrode current collector (113a) and a first active material layer (113b) on the first electrode current collector (113a). The first active material layer (113b) may be formed by applying an electrode active material to one or both sides of the first electrode current collector (113a). Additionally, a first electrode tab (113c) may be attached to an area of ​​the first electrode current collector (113a) where the electrode active material is not applied.

[0057] As illustrated in the example, the electrode active material may not be applied to the core-side end of the first electrode current collector (113a), and the first electrode tab (113c) may be attached to this area. The first electrode (113) may be a negative electrode, and the first electrode tab (113c) may be a negative electrode tab.

[0058] An exposed portion (113d) in which the electrode active material is not applied may be disposed in the area disposed on the outer edge of the electrode assembly (110) in the first electrode current collector (113a). The exposed portion (113d) may be a negative electrode-free portion.

[0059] The second electrode (111) may include a second electrode current collector (111a) and a second active material layer (111b) on the second electrode current collector (111a). The second active material layer (111b) may be formed by applying an electrode active material to one or both sides of the second electrode current collector (111a). Additionally, a second electrode tab (111c) may be attached to an area of ​​the second electrode current collector (111a) where the electrode active material is not applied. As illustrated in the example, the second electrode tab (111c) may be attached to the center of the second electrode current collector (111a), and the second active material layer (111b) may be disposed on both sides of the second electrode tab (111c) on the second electrode current collector (111a). The second electrode (111) may be a positive electrode, and the second electrode tab (111c) may be a positive electrode tab.

[0060] A sealing tape (170) may be placed on the outer surface of the electrode assembly (110). In one embodiment of the present invention, the sealing tape (170) may be placed along the circumferential direction on the outer surface of the jelly roll-shaped electrode assembly (110) as shown in FIG. 3, and may be attached to the upper and lower parts of the jelly roll-shaped electrode assembly (110), respectively.

[0061] The sealing tape (170) can be attached to the outer surface of the separator (112) or electrode (111, 113) that is positioned on the outer side of the electrode assembly (110).

[0062] In this embodiment, the sealing tape (170) can be placed along the entire circumferential direction of the electrode assembly (110) and can wrap around the entire outer surface of the electrode assembly (110). In this way, the sealing tape (170) is placed on the outer surface of the electrode assembly (110) to prevent the jelly roll-shaped electrode assembly (110) from unraveling.

[0063] Meanwhile, FIGS. 6 and 7 are drawings illustrating an electrode inspection device (1000) in an embodiment of the present invention. FIG. 6 is a drawing illustrating the configuration of a front inspection device that inspects the front surface of an electrode in an electrode inspection device in an embodiment of the present invention, and FIG. 7 is a drawing illustrating the configuration of a rear inspection device that inspects the rear surface of an electrode in an electrode inspection device in an embodiment of the present invention.

[0064] In one embodiment of the present invention, the electrode inspection device may include an electrode front inspection device (1100) and an electrode rear inspection device (1300).

[0065] The electrode front inspection device (1100) may be a device for inspecting the front (top surface) of the electrodes (111, 113). The electrode front inspection device (1100) may include a front inspection camera (1110) and a side light (1200) as shown in FIG. 6.

[0066] As shown in FIG. 6, the front inspection camera (1110) may be a camera for acquiring an image or video of the front of an electrode (111, 113) guided by two rollers (1101a, 1101b).

[0067] One of the two rollers (1101a, 1101b) may be an entry roller (1101a) and the other may be an exit roller (1101b). The electrodes (111, 113) may be guided and moved by the entry roller (1101a) and the exit roller (1101b).

[0068] The front inspection camera (1110) can acquire a front image or video of the electrode (111, 113) while the electrode (111, 113) moves between the entry side roller (1101a) and the exit side roller (1101b).

[0069] The front inspection camera (1110) may be positioned at an angle rather than perpendicular to the electrodes (111, 113). That is, the angle (γ) that the front inspection camera (1110) makes with the electrodes may be 90 degrees or less, 40 to 80 degrees, or 50 to 70 degrees.

[0070] The front inspection camera (1110) may be a Contact Image Sensor (CIS) camera. The CIS camera is characterized by a short working distance (WD), which allows the inspection space to be reduced compared to a line scan camera with a long working distance.

[0071] Additionally, the image sensor, lens, and LED can be integrated into the CIS camera. Also, while line scan cameras have a field of view in the lens when viewing a wide area, the CIS camera can be telecentric. The working distance of a line scan camera changes depending on the lens, but the working distance (WD) of a CIS camera can be fixed. The FOV of a line scan camera changes depending on the lens, but the CIS camera can be manufactured to match the FOV (Field Of View). In this embodiment, the FOV of the CIS camera as the front inspection camera (110) can be, for example, 146mm.

[0072] Accordingly, in this embodiment, by applying a CIS camera as the front inspection camera (1110), the inspection space can be reduced, and notching tab inspection can be performed with clear image quality. Therefore, it is possible to simultaneously inspect the notching tab and the width / surface with a single camera. In this embodiment, the front inspection camera (110) may be located about 14 mm away from the object to be inspected.

[0073] The side light (1200) can irradiate light onto the front surface of the electrodes (111, 113) at a predetermined angle from the direction of the front inspection camera (1110). The angle (α) formed by the side light (1200) with the front inspection camera (1110) may be approximately 40 to 50 degrees, or approximately 45 degrees. In this embodiment, the front inspection camera (1110) is positioned obliquely with respect to the electrodes (111, 113) (angle (γ)), ​​and the side light (1200) is positioned at a predetermined angle (α) from the direction of the front inspection camera (1110), thereby allowing the inspection space to be reduced while ensuring inspection image quality.

[0074] Additionally, the electrode front inspection device (1100) may further include a rear light (1250). The rear light (1250) may be positioned opposite the front inspection camera (1110) to the electrodes (111, 113). That is, the rear light (1250) may illuminate the rear surface of the electrodes (111, 113) from the opposite side of the front inspection camera (1110). The light irradiation direction of the rear light (1250) may be in a straight line with the front inspection camera (1110) as shown in FIG. 6. The rear light (1250) may irradiate light between two rollers (1101a, 1101b).

[0075] In this way, the rear lighting (1250) can illuminate the rear surface of the electrodes (111, 113) to perform a slitting burr inspection. A slitting burr may be a type of foreign matter generated during the electrode slitting process.

[0076] The electrode rear inspection device (1300) may be a device for inspecting the rear surface of electrodes (111, 113). The electrode rear inspection device (1300) may include a rear inspection camera (1310) and a side light (1350) as shown in FIG. 7.

[0077] As illustrated in FIG. 7, the rear inspection camera (1310) may be a camera for acquiring an image or video of the rear of an electrode (111, 113) guided by two rollers (1301a, 1301b).

[0078] One of the two rollers (1301a, 1301b) may be an entry roller and the other may be an exit roller. The electrode (111, 113) may be guided and moved by the entry and exit rollers (1301a, 1301b). For example, as shown in FIG. 7, the electrode (111, 113) moving on the entry roller (1301a) may move to the underside of the exit roller (1301b) and then exit by riding on the exit roller (1301b).

[0079] The rear inspection camera (1310) can acquire a rear image or video of the electrode (111, 113) while the electrode (111, 113) moves between two rollers (1301a, 1301b).

[0080] The rear inspection camera (1310) may be positioned obliquely with respect to the electrodes (111, 113). That is, the angle (θ) formed by the rear inspection camera (1310) with respect to the electrodes (111, 113) may be 90 degrees or less, 30 to 60 degrees, or 40 to 50 degrees.

[0081] The rear inspection camera (1310) may be a Contact Image Sensor (CIS) camera. The CIS camera is characterized by a short working distance (WD), which allows the inspection space to be reduced compared to a line scan camera with a long working distance.

[0082] The side light (1350) can irradiate light onto the rear surface of the electrodes (111, 113) at a predetermined angle from the direction of the rear inspection camera (1310). The angle (β) formed by the side light (1350) with the rear inspection camera (1310) may be approximately 80 to 100 degrees, and may be approximately 90 degrees.

[0083] In this embodiment, the rear inspection camera (1310) is positioned obliquely with respect to the electrodes (111, 113) (angle (θ)), and the side lighting (1350) is positioned at a predetermined angle (β) from the direction of the rear inspection camera (1310), thereby allowing the inspection space to be reduced while ensuring clear inspection image quality.

[0084] Figure 8 is an anode test inspection image acquired with a conventional line scan inspection machine, and as shown, it is determined that notching tab inspection is impossible because there is shading on the notching tab.

[0085] In contrast, FIG. 9 is an anode test inspection image acquired by an electrode inspection device according to an embodiment of the present invention, in which the notching tab is clearly visible without shading and the tab is not bent or attached, making notching tab inspection possible. In addition, the electrode width line is clearly distinguished, so width / surface inspection can also be performed on the same image.

[0086] In this embodiment, the electrode inspection device has the configuration described above, so that notching tab and width / surface inspection can be performed simultaneously with one camera, the quality of the inspection image is improved, and the inspection space can be reduced by about 70%.

[0087] Meanwhile, a plurality of cylindrical battery cells (100) can be accommodated in a pack case (2100) to form a battery pack (2000) (see FIG. 10).

[0088] The battery pack (2000) may additionally include various control and protection systems such as a Battery Management System (BMS), and the battery pack (2000) may be applied to various devices. Specifically, it may be applied to means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles, or to an Energy Storage System (ESS), but is not limited thereto and can be applied to various devices capable of using secondary batteries.

[0089] FIG. 11 is a drawing illustrating an electric vehicle (V) equipped with a battery pack (2000). In the electric vehicle (V), the wheels are driven by a motor that receives power from the battery pack (2000), allowing the electric vehicle to operate.

[0090] Although the present invention has been described with reference to preferred embodiments as described above, it is not limited to the aforementioned embodiments, and various changes and modifications may be made by those skilled in the art within the scope of the invention without departing from the spirit of the invention.

[0091] The present invention can provide an electrode inspection device for a secondary battery that can inspect electrodes with a small number of cameras and reduce the inspection space.

Claims

1. A front inspection camera for inspecting the front surface of an electrode; and An electrode inspection device for a secondary battery comprising an electrode front inspection device that includes a side illumination device that irradiates light onto the front surface of the electrode at a certain angle with the front inspection camera.

2. In Paragraph 1, The above-mentioned front inspection camera is a CIS (Contact Image Sensor) camera, an electrode inspection device for secondary batteries.

3. In Paragraph 1, An electrode inspection device for a secondary battery in which the angle formed by the front inspection camera with the electrode is 50 to 70 degrees.

4. In Paragraph 1, An electrode inspection device for a secondary battery in which the angle formed by the side illumination with the front inspection camera is 40 to 50 degrees.

5. In Paragraph 1, The above electrode front inspection device is an electrode inspection device for a secondary battery that further includes a back light that irradiates light onto the back surface of the electrode.

6. In Paragraph 5, A secondary battery electrode inspection device in which the direction of illumination of the above-mentioned rear light is aligned with the above-mentioned front inspection camera.

7. In Paragraph 1, The above electrode front inspection device is an electrode inspection device for a secondary battery that further includes two rollers for guiding the movement of the electrode.

8. In Paragraph 1, A rear inspection camera for inspecting the rear surface of the above electrode; and An electrode inspection device for a secondary battery further comprising an electrode rear inspection device comprising: a side light that irradiates light onto the rear surface of the electrode at a certain angle with the rear inspection camera.

9. In Paragraph 8, The above rear inspection camera is a CIS camera, an electrode inspection device for secondary batteries.

10. In Paragraph 8, An electrode inspection device for a secondary battery in which the angle formed by the rear inspection camera with the electrode is 30 to 60 degrees.

11. In Paragraph 8, An electrode inspection device for a secondary battery in which the angle formed by the side illumination of the electrode rear inspection device with the rear inspection camera is 80 to 100 degrees.

12. In Paragraph 8, The above electrode rear inspection device is an electrode inspection device for a secondary battery that further includes two rollers for guiding the movement of the electrode.

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