Laser welding jig and method for manufacturing battery

Abstract

The invention relates to a jig for laser welding and a method for manufacturing a battery. This laser welding jig (2) can be used when laser welding is performed by irradiating a portion to be welded (115) with laser light, and is provided with: a housing section (10) capable of housing the portion to be welded (115) in a first direction; and an inclined surface (20) extending in the circumferential direction so as to surround the portion to be welded (115) around an axis in the first direction, the inclined surface (20) being capable of reflecting laser light emitted toward the laser welding jig (2) in a second direction intersecting the first direction and toward the portion to be welded (115).

Description

Technical Field

[0001] This technology relates to methods for manufacturing fixtures and batteries for laser welding. Background Technology

[0002] Japanese Patent Application Publication No. 2015-163412 shows a method of joining two components that constitute the battery casing by laser welding.

[0003] If the laser used for bonding reaches the interior of the housing, it may affect the electrode body housed within the housing. On the other hand, it is also necessary to reduce the complexity of the laser welding process. Summary of the Invention

[0004] The purpose of this technology is to provide a method for manufacturing a laser welding fixture and a battery that can suppress the complexity of the laser welding process and obtain a highly reliable laser welded part.

[0005] This technology provides the following methods for manufacturing laser welding fixtures and batteries.

[0006] [1] A laser welding fixture is used when laser welding is performed by irradiating a part to be welded with a laser. The laser welding fixture includes: a receiving portion that can receive the part to be welded along a first direction; and an inclined surface that extends in the circumferential direction around the part to be welded on an axis about the first direction. The inclined surface can cause the laser emitted toward the laser welding fixture to be reflected toward a second direction that intersects with the first direction and toward the part to be welded.

[0007] [2] According to the laser welding fixture described in [1], the laser welding fixture includes a substrate and a coating, the coating being disposed on the surface of the substrate located on the inclined surface, and the laser has superior reflectivity compared to the substrate.

[0008] [3] The laser welding fixture described in [1] or [2], wherein the aforementioned receiving portion and the aforementioned inclined surface are made of a single metal component.

[0009] [4] The laser welding fixture described in any one of [1] to [3] further comprises an outlet capable of ejecting inert gas toward the part to be welded.

[0010] [5] A method for manufacturing a battery, wherein the method comprises: a step of preparing a housing body having an opening opening toward the first direction and a sealing body for sealing the opening; a step of arranging a laser welding fixture described in any one of [1] to [4] in such a way as to surround the joint between the housing body and the sealing body; and a step of irradiating the laser from a laser device parallel to the laser welding fixture in the first direction toward the inclined surface of the laser welding fixture, and performing laser welding on the housing body and the sealing body by means of the laser reflected from the inclined surface in the second direction.

[0011] [6] According to the battery manufacturing method described in [5], the laser device includes optical components of a scanning optical system or a beam rotator system.

[0012] [7] The battery manufacturing method described in [5] or [6] includes reflecting the laser from the laser device onto the inclined surface and reflecting other light with a wavelength different from the laser onto the inclined surface.

[0013] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description relating to the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0014] Figure 1 This is a front view showing the structure of a secondary battery according to one embodiment.

[0015] Figure 2 This indicates viewing from the direction of arrow II. Figure 1 The diagram shows the state of the secondary battery.

[0016] Figure 3 This indicates viewing from the direction of arrow III. Figure 1 The diagram shows the state of the secondary battery.

[0017] Figure 4 This indicates viewing from the direction of arrow IV. Figure 1 The diagram shows the state of the secondary battery.

[0018] Figure 5 This indicates viewing from the direction of arrow V. Figure 1 The diagram shows the state of the secondary battery.

[0019] Figure 6 This is the front view of a laser welding fixture.

[0020] Figure 7 yes Figure 6 Sectional view VII-VII in the figure.

[0021] Figure 8 This is a schematic diagram showing the structure of a laser welding device.

[0022] Figure 9 This is a cross-sectional view showing an example of the shape of the sealing plate.

[0023] Figure 10 This is a cross-sectional view showing another example of the shape of the sealing plate.

[0024] Figure 11 This is a diagram (Figure 1) illustrating the laser welding process.

[0025] Figure 12 This is a diagram (Figure 2) illustrating the laser welding process.

[0026] Figure 13 This is a diagram (Figure 3) illustrating the laser welding process.

[0027] Figure 14 This is a diagram used to illustrate the position of laser irradiation.

[0028] Figure 15 This is a diagram showing the laser welding fixture involved in the modified example. Detailed Implementation

[0029] The embodiments of this technology will be described below. Furthermore, there are instances where the same or equivalent parts are labeled with the same reference numerals without repeating their description.

[0030] Furthermore, in the embodiments described below, when numbers, quantities, etc., are mentioned, the scope of this technology is not limited to those numbers, quantities, etc., unless specifically stated otherwise. Additionally, in the embodiments described below, unless specifically stated otherwise, each constituent element is not necessarily essential to this technology. Furthermore, this technology is not limited to technologies that must perform all the effects mentioned in this embodiment.

[0031] Furthermore, in this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a component is included, other components besides that component may be included, or they may not be included.

[0032] Furthermore, when using geometric terms and terms indicating positional or directional relationships, such as "parallel," "orthogonal," "tilted at 45°," "coaxial," and "along," these terms allow for some degree of error or variation. When using terms indicating relative positional relationships, such as "upper side" and "lower side," these terms are used to indicate relative positional relationships in a given state. Depending on the orientation of each mechanism (e.g., reversing the overall orientation of the mechanism), the relative positional relationships can be reversed or rotated to any angle.

[0033] In this specification, "secondary battery" is not limited to lithium-ion batteries, but may include other secondary batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" can be used to refer to both the positive and negative electrode.

[0034] Furthermore, in the accompanying drawings, the direction of the long side (the direction of the longest side) of the electrode body of the secondary battery is designated as the X direction. Additionally, the direction of the short side of the electrode body when viewed from the X direction is designated as the Y direction, and the direction of the long side of the electrode body when viewed from the X direction is designated as the Z direction. For ease of understanding of the invention, some dimensions of the structures in the accompanying drawings are shown as variations from actual dimensions.

[0035] In this application specification, the Y direction is sometimes referred to as the "thickness direction" of the secondary battery or the main body of the casing, the Z direction is referred to as the "height direction" of the secondary battery or the main body of the casing, and the X direction is referred to as the "width direction" of the secondary battery or the main body of the casing.

[0036] Figure 1 This is a front view of a secondary battery 1 according to an embodiment. Figures 2-5 These represent observations from the directions of arrows II, III, IV, and V, respectively. Figure 1 The diagram shows the state of secondary battery 1 (non-aqueous electrolyte secondary battery).

[0037] The secondary battery 1 can be installed in electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs). However, the application of the secondary battery 1 is not limited to vehicle use.

[0038] like Figures 1-5 As shown, the secondary battery 1 (square secondary battery) includes a casing 100 (battery casing), electrode bodies (not shown), and electrode terminals 300. The casing 100 includes a casing body 110, a sealing plate 120, and a sealing plate 130.

[0039] When constructing a battery pack including secondary batteries 1, multiple secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 can be constrained by a constraint member in the stacking direction (Y direction) to form a battery module, or the battery pack can be directly supported on the side of the battery pack's outer casing without using a constraint member.

[0040] The outer casing 110 is composed of a cylindrical component, preferably a square cylindrical component. This results in a square secondary battery 1. The outer casing 110 is made of metal. Specifically, the outer casing 110 is made of aluminum, aluminum alloy, iron, or an iron alloy, etc.

[0041] like Figure 1 , Figure 2 As shown, sealing plates 120 and 130 are respectively provided at both ends of the outer casing body. The outer casing body 110 is constructed, for example, by having the end edges of a bent plate-like component abut against each other (in... Figure 2 The joints 115 shown in the example are joined together by laser welding and can be formed into a square tube shape. The corners of the "square tube shape" can also have rounded shapes.

[0042] In this embodiment, the outer casing 110 is formed to be longer in the width direction (X direction) than in the thickness direction (Y direction) and height direction (Z direction) of the secondary battery 1.

[0043] The outer casing body 110 includes a pair of first side faces 111 and a pair of second side faces 112. The pair of first side faces 111 form part of the side surface of the outer casing 100. The pair of second side faces 112 form the bottom surface and the top surface of the outer casing 100. The pair of first side faces 111 and the pair of second side faces 112 are respectively arranged to intersect each other. The pair of first side faces 111 and the pair of second side faces 112 are connected at their respective ends. Preferably, the area of ​​each of the pair of first side faces 111 is larger than the area of ​​each of the pair of second side faces 112.

[0044] like Figure 5 As shown, a gas discharge valve 150 is provided on one of the pair of second side surfaces 112, specifically on the second side surface 112B (first wall portion). Figure 5 In the example, the gas discharge valve 150 is located in the central portion of the secondary battery 1 in the width direction (X direction). In this embodiment, the gas discharge valve 150 is located on a wall surface different from the sealing plates 120 and 130. The position and shape of the gas discharge valve 150 can be appropriately changed.

[0045] The thickness of the plate-shaped component at the gas discharge valve 150 is thinner than the thickness of the plate-shaped components other than the gas discharge valve 150 in the housing body 110. As a result, when the pressure inside the housing 100 becomes above a predetermined value, the gas discharge valve 150 ruptures preferentially compared to other parts in the housing body 110, thereby discharging the gas inside the housing 100 to the outside.

[0046] like Figure 2 As shown, a joining portion 115 is formed on another second side surface portion 112A (second wall portion) of a pair of second side surface portions 112. The joining portion 115 extends in the width direction (X direction) of the secondary battery 1. At the joining portion 115, the end edges of the plate-shaped members constituting the housing body 110 are joined together.

[0047] like Figure 3 As shown, an opening 113 (first opening) is provided at the end of the first side in the X direction of the outer casing 110. The opening 113 is sealed by a sealing plate 120. A joint 115 is formed in the opening 113 to seal it. The opening 113 and the sealing plate 120 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction. Furthermore, the generally rectangular shape includes a rectangular shape, or a shape whose corners are rounded, etc., that is substantially rectangular.

[0048] A negative terminal 301 is provided on the sealing plate 120 (the first sealing plate). The position of the negative terminal 301 can be changed appropriately.

[0049] like Figure 4 As shown, an opening 114 (second opening) is provided at the end of the second side of the outer casing 110, opposite to the first side in the X direction. That is, the opening 114 is located at the end opposite to the opening 113, and the openings 113 and 114 are opposite to each other. The opening 114 is sealed by a sealing plate 130. A joint 115 is formed in the opening 114 to seal it. The opening 114 and the sealing plate 130 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction.

[0050] A positive terminal 302 and a liquid injection hole 140 are provided on the sealing plate 130 (the second sealing plate). The positions of the positive terminal 302 and the liquid injection hole 140 can be changed appropriately.

[0051] Sealing plates 120 and 130 are made of metal. Specifically, sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0052] The negative terminal 301 (first electrode terminal) is electrically connected to the negative terminal of the electrode body (not shown). The negative terminal 301 is mounted on the sealing plate 120, that is, on the housing 100.

[0053] The positive terminal 302 (second electrode terminal) is electrically connected to the positive electrode of the electrode body (not shown). The positive terminal 302 is mounted on the sealing plate 130, that is, on the housing 100.

[0054] The negative terminal 301 is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. A portion or layer of aluminum or an aluminum alloy may also be provided on the outer surface of the negative terminal 301.

[0055] The positive terminal 302 is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy.

[0056] The injection port 140 is sealed by a sealing component (not shown). As a sealing component, for example, a blind-hole rivet or other metal component can be used.

[0057] The following describes the laser welding process for forming the joint 115 between the outer casing body 110 and the sealing plates 120 and 130, and the laser welding fixture used in this process. However, the laser welding involved in this technology is not limited to applications in... Figures 1-5 The laser welding used to form the joint 115 is illustrated in the example. Furthermore, the laser welding involved in this technology is not limited to laser welding applied to the manufacture of secondary batteries.

[0058] Figure 6 This is the front view of fixture 2 for laser welding. Figure 7 yes Figure 6 Sectional view VII-VII in the figure. Figure 8 This is a schematic diagram showing the structure of a laser welding apparatus, including the laser welding fixture 2.

[0059] like Figure 6 , Figure 7 As shown, the laser welding fixture 2 includes a receiving portion 10 and an inclined surface 20. The receiving portion 10 is formed by a through hole along the direction of arrow DR1. The inclined surface 20 extends in a direction that intersects obliquely with respect to the direction of arrow DR1. In addition, the inclined surface 20 extends circumferentially around the joint portion 115 about an axis about the direction of arrow DR1.

[0060] like Figure 8 As shown, the laser welding fixture 2 can be used when laser welding the joint 115 between the outer shell body 110 and the sealing plates 120 and 130. At this time, the receiving part 10 can receive the joint 115 in the direction of arrow DR1 (first direction).

[0061] The inclined surface 20 enables the laser F1 emitted from the laser device 3 toward the laser welding fixture 2 to be reflected toward the direction of arrow DR2 (the second direction), which intersects with the direction of arrow DR1. Furthermore, arrow DR1 and arrow DR2 are typically approximately orthogonal, but the scope of this technology is not limited thereto.

[0062] The substrate of the laser welding fixture 2 can be made of a metal material that is heat-resistant to lasers (e.g., Cu (copper)). The receiving part 10 and the inclined surface 20 of the laser welding fixture 2 can be made of a single metal component or a combination of multiple components.

[0063] On the surface of the inclined surface 20, a coating with superior laser reflectivity compared to the substrate can also be applied. Examples of coatings with superior reflectivity include metal layers (Au (gold), Ag (silver), Al (aluminum), etc.) and dielectric multilayer films.

[0064] In addition, dielectric multilayer films are coatings formed by alternating layers of transparent and high refractive index films (such as TiO2, HfO2, etc.) and transparent and low refractive index films (SiO2, MgF2) with a phase of 90° (1 / 4 phase).

[0065] The laser device 3 is positioned parallel to the laser welding fixture 2 in the direction of arrow DR1. The laser device 3 may also include optical components of a scanning optical system or a beam rotator system.

[0066] The laser device 3 irradiates laser F1 towards the inclined surface 20 of the laser welding fixture 2. Laser F1 is reflected by the inclined surface 20 and becomes laser F2 directed towards arrow DR2. The focal length is set in a manner that obtains a predetermined output at the joint 115.

[0067] In addition to reflecting the laser F1 from the laser device 3 onto the inclined surface 20, other light with a different wavelength than the laser (e.g., light used in OCT (Optical Coherence Tomography)) can also be reflected onto the inclined surface 20.

[0068] The wavelength of the laser is, for example, between 180 nm and 10800 nm (more preferably between 1030 nm and 1080 nm). The wavelength of the light used in OCT is, for example, between 800 nm and 1500 nm (more preferably between 800 nm and 900 nm). The wavelength of the light used in OCT can be set so that it does not overlap with the wavelength of the laser.

[0069] Figure 9 , Figure 10 This is a cross-sectional view showing an example of the shape of the sealing plate 130. It can be like... Figure 9As in the example, the sealing plate 130 is set on the outside of the outer shell body 110, or it can be like... Figure 10 As in the example, a portion of the sealing plate 130 is inserted into the inside of the housing body 110.

[0070] Next, use Figures 11-14 The manufacturing method of the secondary battery 1, including the laser welding process using the laser welding fixture 2, will be described.

[0071] like Figure 11 As shown, a housing body 110 with openings 113 and 114 (opening portions) is prepared, and a sealing plate 130 (sealing body) is prepared to seal the openings 113 and 114. An electrode body (not shown) is housed in the housing body 110.

[0072] Next, as Figure 12 As shown, a laser welding fixture 2 is provided in such a way that it surrounds the joint 115 between the outer shell body 110 and the sealing plate 130.

[0073] Next, laser F1 is irradiated from the laser device 3 toward the inclined surface 20 of the laser welding fixture 2, as follows: Figure 13 As shown, laser welding is performed on the outer shell body 110 and the sealing plate 130 by laser F2 reflected in the direction of arrow DR2 from the inclined surface 20.

[0074] like Figure 14 As shown, laser F1 is irradiated from the irradiation start point A and in a manner that surrounds the inclined surface 20 extending circumferentially.

[0075] According to the laser welding fixture 2 of this embodiment, by reflecting the laser on the inclined surface 20 and changing its direction, the laser can be irradiated on the joint 115 from any angle. Therefore, it is possible to obtain a laser welded part that suppresses the large-scale manufacturing equipment, the increase in production interval time, and has high reliability.

[0076] Figure 15 This is a diagram showing the laser welding fixture 2 involved in the modified example. Figure 15 In a modified example, the laser welding fixture 2 has an outlet 30 capable of ejecting inert gas toward the joint 115. By ejecting inert gas toward the part to be welded, the reliability of the welding can be further improved.

[0077] While embodiments of the invention have been described, it should be understood that the disclosed embodiments are exemplary in all respects and not restrictive. The scope of the invention is defined by the claims and is intended to include all modifications within the meaning and scope of the claims.

Claims

1. A laser welding fixture, which is used for laser welding by irradiating the part to be welded with a laser, wherein, The laser welding fixture includes: The receiving portion is capable of receiving the welded portion along the first direction; and An inclined surface extends circumferentially around the welded portion in such a way that it surrounds the welded portion about an axis in the first direction. The inclined surface enables the laser emitted toward the laser welding fixture to be reflected toward a second direction that intersects with the first direction and toward the part to be welded.

2. The laser welding fixture according to claim 1, wherein, The laser welding fixture includes a substrate and a coating, the coating being disposed on the surface of the substrate located on the inclined surface, and the laser exhibiting superior reflectivity compared to the substrate.

3. The laser welding fixture according to claim 1 or 2, wherein, The receiving portion and the inclined surface are made of a single metal component.

4. The laser welding fixture according to claim 1 or 2, wherein, The laser welding fixture also has an outlet capable of spraying inert gas toward the part to be welded.

5. A method for manufacturing a battery, wherein, The method for manufacturing the battery comprises: A process for preparing a housing body having an opening facing the first direction and a sealing body for sealing the opening; The process of setting up the laser welding fixture according to claim 1 or 2 in such a way as to surround the joint between the outer shell body and the sealing body; and The process of laser welding the outer shell body and the sealing body by irradiating the laser device, which is parallel to the laser welding fixture in the first direction, toward the inclined surface of the laser welding fixture, and performing laser welding on the outer shell body and the sealing body by the laser reflected from the inclined surface in the second direction.

6. The method for manufacturing a battery according to claim 5, wherein, The laser device includes optical components of a scanning optical system or a beam rotator system.

7. The method for manufacturing a battery according to claim 5, wherein, The method of manufacturing the battery includes reflecting the laser light from the laser device onto the inclined surface and reflecting other light with a wavelength different from the laser light onto the inclined surface.

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