Manufacturing method of secondary battery and secondary battery

Abstract

To provide a manufacturing method of a secondary battery configured not to damage an electrode body in a battery case when fixing a sealing plate to an opening of an angular outer can, and the secondary battery.SOLUTION: In a manufacturing method of a secondary battery 1, the secondary battery comprises: an electrode body 200 an angular outer can 110 including an opening 110h; and a sealing plate 120 which seals the opening 110h in a state where the electrode body 200 is stored inside of the angular outer can 110. The manufacturing method of the secondary battery includes the step of fixing the sealing plate 120 to the opening 110h using a laser beam and includes the steps of: disposing the sealing plate 120 to the opening 110h; performing temporary welding to a plurality of selected locations between the opening 110h and the sealing plate 120 with a laser beam; and then performing full circumferential welding on a full circumference between the opening 110h and the sealing plate 120 continuously with a laser beam.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present technology relates to a manufacturing method of a secondary battery and a secondary battery. [Background technology]

[0002] A prismatic secondary battery having a configuration in which an electrode body is housed in a battery case together with an electrolyte is disclosed in, for example, JP 2013-187087 A (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-187087 A Summary of the Invention [Problem to be solved by the invention]

[0004] The battery case of the secondary battery described above is composed of a rectangular outer can having an opening and a sealing plate that seals the opening of the rectangular outer can. The sealing plate is attached to the opening of the battery case by laser welding. During laser welding, the gap between the rectangular outer can and the sealing plate increases due to the heat caused by the temperature rise. As a result, the laser for the laser welding may penetrate into the inside of the rectangular outer can through the gap and cause damage to the electrode body in the battery case.

[0005] An object of the present technology is to provide a manufacturing method for a secondary battery, and a secondary battery that has a configuration that does not damage an electrode body inside a battery case when a sealing plate is fixed to an opening of a rectangular outer can. [Means for solving the problem]

[0006] The present technology provides the following method for producing a secondary battery.

[0007] [1] A method for manufacturing a secondary battery comprising an electrode body, an outer can having an opening, and a sealing plate that houses the electrode body inside the outer can and seals the opening, the method comprising the steps of: fixing the sealing plate to the opening using laser light; placing the sealing plate in the opening and temporarily welding selected locations between the opening and the sealing plate with the laser light; and then continuously welding the entire circumference between the opening and the sealing plate with the laser light.

[0008] [2] The method for manufacturing a secondary battery according to [1], wherein in the step of performing the temporary welding, when the sealing plate is placed over the opening of the outer casing and viewed in plan, the laser light is irradiated in a state in which an optical axis of the laser light is inclined from the inside to the outside of the opening.

[0009] [3] The method for manufacturing a secondary battery according to [1] or [2], wherein in the step of performing the temporary welding, an optical axis of the laser light intersects with a side edge of the sealing plate and is moved from the inside to the outside of the opening while performing the welding.

[0010] [4] The method for manufacturing a secondary battery according to any one of [1] to [3], wherein in the step of performing the all-around welding, the laser light is irradiated in a state in which the sealing plate is placed at the opening of the outer can and an optical axis of the laser light is perpendicular to the sealing plate.

[0011] [5] The method for manufacturing a secondary battery according to any one of [2] to [4], wherein the outer can is a bottomed, rectangular cylindrical outer can having the opening, a length of the rectangular outer can is 300 mm or more, a plate thickness of the rectangular outer can is 0.65 mm or less, a spacing of the temporary welds is 80 mm or less, and in the step of performing the temporary welding, an irradiation angle of the laser light is inclined by approximately 3 degrees or more with respect to a perpendicular to the sealing plate, the laser light has a core diameter of 0.26 mm to 0.34 mm and a ring diameter of the beam of 0.77 mm to 0.98 mm, and the laser light has an output of 700 (W) to 1000 (W) for the core and 4800 (W) to 7000 (W) for the ring, and a scanning speed of the laser light is 100 mm / s to 220 mm / s.

[0012] [6] The method for manufacturing a secondary battery described in any one of [1] to [5], wherein the sealing plate includes a first electrode and a second electrode, and a spacing between the temporary welds provided around the first electrode and the second electrode is smaller than a spacing between the temporary welds provided in other regions.

[0013] [7] The method for producing a secondary battery according to any one of [1] to [6], wherein the secondary battery is a lithium ion battery.

[0014] The present technology provides the following secondary battery. [8] A secondary battery comprising an electrode body, an outer can having an opening, and a sealing plate that houses the electrode body inside the outer can and seals the opening, wherein between the sealing plate and the opening there is a full circumferential weld provided around the entire circumference of the opening, and a plurality of temporary welds that are provided in contact with the inside of the full circumferential weld and are recessed in the thickness direction of the sealing plate.

[0015] [9] The secondary battery described in [8], wherein the sealing plate includes a first electrode and a second electrode, and the spacing between the pre-welded portions provided around the first electrode and the second electrode is smaller than the spacing between the pre-welded portions provided in other regions.

[0016]

[10] The secondary battery according to [8] or [9], wherein the outer can is a bottomed rectangular cylindrical outer can having the opening, and the battery is a lithium ion battery. Effect of the Invention

[0017] According to the present technology, it is possible to provide a method for manufacturing a secondary battery and a secondary battery having a configuration that does not damage the electrode body inside the battery case when fixing the sealing plate to the opening of the rectangular outer can. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view of a prismatic secondary battery according to an embodiment of the present invention; [Diagram 2] 1A to 1C are first plan views illustrating a manufacturing process for a prismatic secondary battery according to the present embodiment. [Diagram 3] 5A to 5C are second plan views illustrating the manufacturing process of the prismatic secondary battery according to the present embodiment. [Figure 4] 4 is a plan view showing details of temporary welding in a manufacturing process of the prismatic secondary battery according to the present embodiment. FIG. [Diagram 5] 5 is a vertical cross-sectional view showing details of temporary welding in a manufacturing process of the prismatic secondary battery according to the present embodiment. FIG. [Figure 6] FIG. 4 is a flow diagram showing a welding process according to the present embodiment. [Figure 7] 4A to 4C are diagrams showing a process of performing temporary welding according to the present embodiment. [Figure 8] 4A and 4B are schematic diagrams showing irradiation angles of laser light according to the embodiment; [Figure 9] FIG. 2 is a schematic diagram showing a scanning direction of a laser beam according to the present embodiment. [Figure 10] 1A to 1C are diagrams showing a process of performing full circumference welding according to the present embodiment. [Figure 11] 5A to 5C are diagrams illustrating irradiation conditions of laser light according to the present embodiment. [Figure 12] 3A and 3B are schematic diagrams showing the diameter of a core of a laser beam and the diameter of a ring of the beam in the present embodiment. [Figure 13]FIG. 4 is a schematic diagram showing a welding state of a comparative example. [Figure 14] FIG. 2 is a schematic diagram showing a welding state according to the present embodiment. [Figure 15] 10 is a diagram showing a schematic diagram of a gap generated between an opening and a sealing plate before welding. FIG. [Figure 16] FIG. 13 is a diagram showing the evaluation results of the relationship between the total output (W) of the laser light and the change in the gap generated between the opening and the sealing plate. [Figure 17] FIG. 13 is a diagram showing an evaluation of the presence or absence of laser welds when no temporary welds are provided. [Figure 18] FIG. 13 is a diagram showing an evaluation of the presence or absence of laser weld loss when a temporary weld is provided. [Figure 19] FIG. 13 is a diagram showing an evaluation of laser penetration depending on the irradiation angle of the laser light when a temporary weld is provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof will not be repeated.

[0020] In the embodiments described below, when numbers, amounts, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to the numbers, amounts, etc. In addition, in the embodiments described below, each component is not necessarily essential to the present technology, unless otherwise specified.

[0021] In this specification, the words "comprise", "include", and "have" are open-ended. That is, when a certain configuration is included, other configurations may or may not be included. In addition, the present technology is not limited to those that necessarily achieve all of the effects mentioned in the present embodiment.

[0022] When geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0023] In this specification, the term "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, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0024] In the drawings, the width direction (left-right direction on the paper) of the secondary battery's rectangular exterior is the X direction, the thickness direction (depth direction on the paper) is the Y direction, and the height direction (up-down direction on the paper) is the Z direction, and the X direction, Y direction, and Z direction are mutually orthogonal. To facilitate understanding of the invention, the dimensions of each component in the drawings may be altered from their actual dimensions.

[0025] The configuration of a prismatic secondary battery will be described as an example of a secondary battery according to the present embodiment with reference to Fig. 1 to Fig. 5. Fig. 1 is a perspective view of the prismatic secondary battery, Fig. 2 is a first enlarged photograph showing the welded state between the exterior body and the sealing plate, Fig. 3 is an enlarged vertical cross-sectional view of Fig. 2, Fig. 4 is a second enlarged photograph showing the welded state between the exterior body and the sealing plate, and Fig. 5 is an enlarged vertical cross-sectional view of Fig. 3.

[0026] The secondary battery 1 includes a battery case 100, an electrode assembly 200, a first electrode 400 (positive electrode terminal), a second electrode 500 (negative electrode terminal), and a sealing member 900.

[0027] The battery case 100 has, as an outer can, a rectangular outer can 110 in the form of a bottomed rectangular cylinder having an opening 110h, and a sealing plate 120 that seals the opening 110h of the rectangular outer can 110. The rectangular outer can 110 and the sealing plate 120 are each preferably made of metal, and are preferably made of aluminum or an aluminum alloy. The outer dimensions of the rectangular outer can 110 are preferably a width of 30 mm or more, a length of 300 mm or more, and a plate thickness of 0.65 mm or less. The outer dimensions of the sealing plate 120 are preferably a width of 30 mm or more, a length of 300 mm or more, and a thickness of 2 mm or less.

[0028] An electrolyte injection hole 121 is provided in the sealing plate 120. After the electrolyte is injected into the battery case 100 through the electrolyte injection hole 121, the electrolyte injection hole 121 is sealed with a sealing member 900 (such as a rivet).

[0029] The sealing plate 120 is provided with a gas exhaust valve 122. The gas exhaust valve 122 breaks when the pressure inside the battery case 100 reaches or exceeds a predetermined value, thereby allowing the gas inside the battery case 100 to be exhausted to the outside of the battery case 100.

[0030] The electrode assembly 200 is accommodated together with an electrolyte in the battery case 100. The electrode assembly 200 is formed by stacking a positive electrode plate and a negative electrode plate with a separator interposed therebetween. A resin insulating sheet (not shown) is disposed between the electrode assembly 200 and the rectangular outer can 110.

[0031] The first electrode 400 is fixed to the sealing plate 120 via an external insulating member 410 made of resin. The second electrode 500 is fixed to the sealing plate 120 via an external insulating member 510 made of resin.

[0032] The first electrode 400 is preferably made of a metal, more preferably aluminum or an aluminum alloy. The second electrode 500 is preferably made of a metal, more preferably copper or a copper alloy.

[0033] The sealing plate 120 is fixed by welding to the opening 110h of the rectangular outer can 110. Between the sealing plate 120 and the opening 110h, there are provided a circumferential weld WH provided around the entire circumference of the opening 110h, and a plurality of temporary welds WK provided so as to be in contact with the inside of the circumferential weld WH and recessed in the plate thickness direction of the sealing plate 120. The locations where the temporary welds WK are provided will be described in the welding method described below, but depending on the size of the temporary welds WK, there may be locations where the temporary welds WK are lost by the circumferential weld WH.

[0034] 2 and 3, when the inward protruding portion G1 of the tack weld WK at the circumferential weld WH is large, the surface of the tack weld WK has a curved shape that is recessed in the plate thickness direction of the sealing plate 120. When the inward protruding portion G1 of the tack weld WK at the circumferential weld WH is small, as shown in Figures 4 and 5, the surface of the tack weld WK has a recessed shape in which groove 120G provided on the side of the sealing plate 120 is exposed.

[0035] (Process of welding sealing plate 120 to opening 110h of rectangular exterior can 110) Next, with reference to Fig. 6 to Fig. 14, a process of welding the sealing plate 120 to the opening 110h of the rectangular outer can 110 will be described in relation to the manufacturing method of the secondary battery. Fig. 6 is a flow diagram showing the welding process, Fig. 7 is a diagram showing the process of performing temporary welding, Fig. 8 is a schematic diagram showing the irradiation angle of the laser light, Fig. 9 is a schematic diagram showing the scanning direction of the laser light, Fig. 10 is a diagram showing the process of performing full circumference welding, Fig. 11 is a diagram showing the irradiation conditions of the laser light, Fig. 12 is a schematic diagram showing the diameter of the core of the laser light beam and the diameter of the ring of the beam, Fig. 13 is a schematic diagram showing the welding state of a comparative example, and Fig. 14 is a schematic diagram showing the welding state of this embodiment.

[0036] Referring to FIG. 6, the process of welding sealing plate 120 to opening 110h of rectangular outer can 110 includes a step (S10) of checking the component fitting gap between opening 110h and sealing plate 120, a can insertion step (S20) of placing sealing plate 120 on opening 110h, a step (S30) of clamping the temporary weld, a step (S40) of performing temporary welding (diagonal welding), a step (S50) of clamping the entire surface, and a step (S60) of performing main welding (all-around welding).

[0037] 7, the sealing plate 120 is placed in the opening 110h, and temporary welds WK are provided by laser welding at a plurality of selected locations between the opening 110h and the sealing plate 120. In this embodiment, when the outer dimensions of the battery case 100 in a plan view are 300 mm in the width direction (X direction) and 40 mm in the width (Y direction), the temporary welds WK are provided at six locations on each side of the opening 110h in the width direction (X direction), totaling 12 locations. In the width direction (Y direction) of the opening 110h, the temporary welds WK are provided at two locations on each side, totaling four locations. Thus, the temporary welds WK (WK1 to WK16) are provided at 16 locations around the entire circumference of the opening 110h.

[0038] In this embodiment, the first electrode 400 and the second electrode 500 are provided on the sealing plate 120, and the intervals of the temporary fixations provided around the first electrode 400 and the second electrode 500 are set smaller than the intervals of the temporary fixations provided in other regions. Note that in this embodiment, the intervals of the temporary fixations provided around the gas release valve 122 are set smaller than the intervals of the temporary fixations provided in other regions, but the intervals of the temporary fixations provided around the gas release valve 122 may be equal to the intervals of the temporary fixations provided in other regions.

[0039] In this embodiment, in the width direction (X direction) of the sealing plate 120, when the gas exhaust valve 122 is provided at the center CL position in the width direction (X direction) of the sealing plate 120, the temporary welds WK (WK3, 4, 11, 12) are provided at a position with a distance L2 (20 mm in this embodiment) from the center CL, the temporary welds WK (WK2, 5, 10, 13) are provided at a position with a distance L1 (80 mm in this embodiment) from the temporary welds WK, and the temporary welds WK (WK1, 6, 9, 14) are provided at a position with a distance L3 (20 mm in this embodiment) from the temporary welds WK. In the thickness direction (Y direction) of the sealing plate 120, the temporary welds WK (WK7, 8, 15, 16) are provided at a position with a distance L4 (5 mm in this embodiment) from the side edge. The interval between adjacent temporary welds WK is preferably 80 mm or less at most.

[0040] As a result, many temporary welds WK are provided around the first electrode 400 and the second electrode 500. By providing many temporary welds WK around the first electrode 400 and the second electrode 500 in this manner, it is also possible to previously determine the positioning of the opening 110h of the rectangular outer can 110 and the sealing plate 120 in the height direction (Z direction). As a result, it is possible to satisfy the height precision required during busbar welding in a later process.

[0041] 8, when forming the temporary welded portion WK, the optical axis of the laser beam LB is irradiated in a state inclined from the inside to the outside of the opening 110h. The irradiation angle θ of the laser beam LB is preferably inclined by about 3 degrees or more with respect to the perpendicular line VL to the sealing plate 120. By inclining the irradiation angle θ of the laser beam LB from the inside to the outside of the opening 110h in this manner, even if the laser beam LB enters the inside of the rectangular outer can 110 through a gap between the opening 110h and the sealing plate 120, the laser beam LB can be prevented from being directly irradiated to the electrode body 200 accommodated inside the rectangular outer can 110.

[0042] 9, in a plan view, the scanning direction of the laser light LB when forming the temporary welded portion WK may intersect with the side edge 120a of the sealing plate 120, and the welding may be performed while moving from the inside to the outside of the opening 110h. In this embodiment, the crossing angle with respect to the side edge 120a of the sealing plate 120 is about 45 degrees, and the scanning distance D1 in the width direction (X direction) and the scanning distance D2 in the thickness direction (Y direction) are both about 0.7 mm.

[0043] 10, after the temporary weld WK is formed, the entire circumference between the opening 110h and the sealing plate 120 is continuously welded with the laser beam LB to form the entire circumference weld WH. In forming the entire circumference weld WH, a single stroke is preferable in terms of quality assurance and cycle time, and for this purpose, it is preferable to irradiate the laser beam with the optical axis of the laser beam perpendicular to the sealing plate 120. In particular, in this embodiment, since the temporary weld WK is provided in the previous process, welding without laser dropout is possible in the entire circumference welding even if the optical axis of the laser beam is perpendicular to the sealing plate 120.

[0044] The conditions of the laser beam LB in the tack welding and the full circumference welding will be described with reference to Fig. 11 and Fig. 12. A ring mode laser is used for the laser beam LB. The diameter of the core LB1 of the beam of the laser beam LB is preferably 0.26 mm to 0.34 mm, and the diameter of the ring LB2 of the beam is preferably 0.77 mm to 0.98 mm.

[0045] The core power (W) during tack welding is preferably 700 (W) to 1000 (W), the ring power (W) is preferably 4800 (W) to 7000 (W), the scanning speed (mm / s) is preferably 100 mm / s to 220 mm / s, the irradiation angle (degrees) is preferably 8 degrees or less, and the spacing (mm) of the tack welds is preferably 80 mm or less.

[0046] The core power (W) during main welding is preferably 1600 (W) to 2000 (W), the ring power (W) is preferably 3800 (W) to 5000 (W), and the scanning speed (mm / s) is preferably 240 mm / s to 380 mm / s.

[0047] 12, in welding between the opening 110h and the sealing plate 120, when the scanning direction of the laser light LB is set to S1, if the rectangular outer can 110 and the sealing plate 120 are made of aluminum, a molten pool R1 of aluminum is formed on the upstream side of the moving laser light LB. By irradiating the laser light LB through this molten pool R1 and further melting the aluminum, it is possible to prevent the laser from entering the center of the rectangular outer can 110 (laser missing). Thereafter, by moving the laser light, the molten aluminum portion is cooled and solidified, and a weld completion region R2 is formed on the downstream side.

[0048] 13, when the full-circumference welding between the opening 110h and the sealing plate 120 is started, it is considered that the gap between the opening 110h and the sealing plate 120 increases due to the thermal distortion of the laser beam LB. If the gap increases, there is a high possibility that the laser will enter the inside of the rectangular outer can 110.

[0049] 14, in this embodiment, a temporary weld WK is provided between the opening 110h and the sealing plate 120 before starting the full-circumference welding, thereby making it possible to prevent an increase in the gap between the opening 110h and the sealing plate 120 due to thermal distortion of the laser light LB. This makes it possible to prevent the laser from penetrating into the interior of the rectangular outer can 110.

[0050] In the case of the full circumference welding shown in Fig. 13, in order to suppress the expansion of the gap due to the thermal distortion of the laser light LB, a method of dividing the full circumference welding into several steps and providing a cooling time has been adopted. However, dividing the full circumference welding into several steps increases the time required for the full circumference welding. However, in this embodiment, the full circumference welding process is completed in one step, so that the time required for the full circumference welding can be shortened. This can improve the efficiency of the manufacturing process of the secondary battery.

[0051] (Evaluation Results) The evaluation results of the secondary battery 1 described above will be described below with reference to Fig. 15 to Fig. 19. Fig. 15 is a diagram showing a schematic diagram of a gap occurring between the opening 110h and the sealing plate 120 before welding, Fig. 16 is a diagram showing the evaluation results of the total output (W) of the laser light and the change in the gap occurring between the opening and the sealing plate, Fig. 17 is a diagram showing an evaluation of the presence or absence of laser leakage when no temporary welds are provided, Fig. 18 is a diagram showing an evaluation of the presence or absence of laser leakage when temporary welds are provided, and Fig. 19 is a diagram showing an evaluation of laser leakage according to the irradiation angle of the laser light when temporary welds are provided.

[0052] With reference to Fig. 15, the gap (before welding) occurring between the opening 110h and the sealing plate 120 used in the evaluation described below will be described. The above-mentioned rectangular outer can 110 having the opening 110h and the sealing plate 120 were used. Before welding, the end face T1 of the opening 110h and the end face T2 of the sealing plate 120 each have waviness, and the dimensional tolerance of each end face is ±0.05 mm. Therefore, the maximum gap S1 occurring between the end face T1 of the opening 110h and the sealing plate 120 is about 0.2 mm.

[0053] In the evaluation described below, tack welding and full circumference welding were performed in sequence to evaluate the amount of gap increase during welding and the presence or absence of laser penetration. A ring mode laser consisting of a core and a ring, as shown in Figure 12, was used for the laser beam. The laser welding conditions for tack welding and full circumference welding were as shown in Figure 11. Tack welding was performed under the conditions shown in Figures 8 and 9.

[0054] With reference to Fig. 16, the evaluation results of the total output (W) of the laser beam and the change in the gap occurring between the opening and the sealing plate will be described. In the figure, the horizontal axis indicates the total output (W) of the laser beam, and the vertical axis indicates the increase in the gap. The total output (W) of the laser beam is the sum of the core output and the ring output. In the figure, S1 indicates the evaluation result when the can thickness of the rectangular outer can 110 is 0.65 mm (this embodiment) and a temporary weld is provided, S2 indicates the evaluation result when no temporary weld is provided in S1 (comparative example), and S3 indicates the evaluation result when the can thickness of the rectangular outer can 110 is 0.8 mm and no temporary weld is provided (comparative example).

[0055] Comparing S2 and S3 from the evaluation results shown in Fig. 16, it was found that when the can thickness is small and the total output of the laser beam is increased, the size of the gap between the opening and the sealing plate increases. However, as shown in S1, it was confirmed that the provision of a temporary weld can prevent the gap between the opening and the sealing plate from becoming larger.

[0056] 17 and 18, when the gap between the opening and the sealing plate before welding was 0.2 mm, the occurrence of laser leakage was confirmed when no temporary weld was provided (FIG. 17) and when a temporary weld was provided (FIG. 18). In the figure, the horizontal axis shows the core power of the laser light, and the vertical axis shows the ring power of the laser light.

[0057] When no temporary welds were provided as shown in Fig. 17, laser leakage was confirmed by appropriately combining the ring output and core output of the laser light (six locations), and laser leakage was confirmed in every combination (locations indicated by "x" in the figure). On the other hand, as shown in Fig. 18, laser leakage was confirmed when the ring output and core output of the laser light shown in Fig. 17 were combined in the same way, but laser leakage was not confirmed in every combination (locations indicated by "o" in the figure). Comparing Fig. 17 and Fig. 18, it was confirmed that laser leakage can be suppressed by providing temporary welds.

[0058] Referring to Fig. 19, the horizontal axis indicates the irradiation angle (°) of the laser light when forming the temporary weld, and the vertical axis indicates the size of the gap that occurs between the opening and the sealing plate. In this way, the laser leakage associated with the irradiation angle when forming the temporary weld was evaluated. The guaranteed gap on the equipment side that does not cause laser leakage is 0.05 mm. The inclination angle here is the irradiation angle θ shown in Fig. 8.

[0059] The area above line BL1 in the figure indicates an area where laser light may directly penetrate (penetrate) through a gap into the interior of rectangular outer can 110. The area below line BL2 in the figure indicates an area where laser light does not penetrate through a gap into the interior of rectangular outer can 110. An "x" mark in the figure indicates that laser leakage has occurred, and an "o" mark indicates that laser leakage has not occurred.

[0060] From FIG. 19, it is preferable that the irradiation angle θ of the laser light when forming the temporary weld is 3 degrees or more in order to guarantee the above-mentioned equipment-side guaranteed gap of 0.05 mm.

[0061] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0062] 1 secondary battery, 100 battery case, 110 rectangular outer can, 110h opening, 120 sealing plate, 120G groove, 120a side edge, 121 electrolyte injection hole, 122 gas exhaust valve, 200 electrode body, 400 first electrode, 410, 510 outer insulating member, 500 second electrode, 900 sealing member.

Claims

1. An electrode body; an outer can having an opening; a sealing plate that houses the electrode assembly inside the exterior can and seals the opening; A method for producing a secondary battery comprising the steps of: Fixing the sealing plate to the opening using a laser beam; placing the sealing plate in the opening and temporarily welding selected portions between the opening and the sealing plate by the laser light; thereafter, continuously welding the entire circumference between the opening and the sealing plate by the laser light; having A method for manufacturing a secondary battery.

2. In the step of performing the temporary welding, the laser light is irradiated in a state where an optical axis of the laser light is inclined from the inside to the outside of the opening when the sealing plate is viewed in a plan view in a state where the sealing plate is disposed on the opening of the exterior can. The method for producing the secondary battery according to claim 1 .

3. In the step of performing the all-around welding, the laser light is irradiated in a state where the sealing plate is placed on the opening of the exterior can and an optical axis of the laser light is perpendicular to the sealing plate. The method for producing the secondary battery according to claim 1 .

4. In the step of performing the temporary welding, welding is performed while an optical axis of the laser light intersects a side edge of the sealing plate and moves from the inside to the outside of the opening; The method for producing the secondary battery according to claim 1 .

5. the outer can is a rectangular outer can having a bottomed rectangular cylinder shape and the opening, The length of the rectangular outer can is 300 mm or more, The plate thickness of the rectangular outer can is 0.65 mm or less, The interval between the temporary welds is 80 mm or less, In the step of performing the temporary welding, the irradiation angle of the laser light is inclined at about 3 degrees or more with respect to a perpendicular line to the sealing plate, The laser light has a core diameter of a beam of 0.26 mm to 0.34 mm and a ring diameter of the beam of 0.77 mm to 0.98 mm; The laser light has an output of 700 (W) to 1000 (W) for the core and 4800 (W) to 7000 (W) for the ring; The scanning speed of the laser light is 100 mm / s to 220 mm / s. The method for producing the secondary battery according to any one of claims 2 to 4.

6. the sealing plate includes a first electrode and a second electrode, The intervals of the temporary welds provided around the first electrode and the second electrode are set smaller than the intervals of the temporary welds provided in other regions. The method for producing the secondary battery according to claim 1 .

7. The secondary battery is a lithium ion battery. The method for producing the secondary battery according to claim 1 .

8. An electrode body; an outer can having an opening; a sealing plate that houses the electrode assembly inside the exterior can and seals the opening; A secondary battery comprising: Between the sealing plate and the opening, a circumferential weld is provided around the entire circumference of the opening; A plurality of temporary welds are provided in contact with the inside of the circumferential weld and are recessed in the plate thickness direction of the sealing plate; A secondary battery comprising:

9. the sealing plate includes a first electrode and a second electrode, The intervals between the temporary welds provided around the first electrode and the second electrode are smaller than the intervals between the temporary welds provided in other regions. The secondary battery according to claim 8.

10. the outer can is a rectangular outer can having a bottomed rectangular cylinder shape and the opening, The secondary battery is a lithium ion battery. The secondary battery according to claim 8.

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