JP2018181617A - Manufacturing method of secondary battery and secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of secondary battery capable of restraining occurrence of poor weld between the injection hole and the sealant of a secondary battery, and to provide a secondary battery.SOLUTION: A secondary battery is housing electricity generation elements in a battery jar consisting of a battery case and a lid 12. In the secondary battery, the lid 12 has an injection hole 15 for injecting electrolyte into the battery case, the injection hole 15 has a through hole 5c penetrating to the battery jar in the center P0, and a sealant placement part 5a for placing a sealant 30 on the outer boundary of the through hole 5c. The sealant 30 for sealing the injection hole 15 is welded to the injection hole 15, and includes an air vent 33 penetrating the sealant 30, and an inclined plane 32 recessed toward the air vent 33 in the internal surface 30b facing the injection hole 15, where the air vent 33 is sealed by welding.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method of manufacturing a secondary battery having an injection hole into which an electrolytic solution is injected, and a secondary battery.

  Usually, in the manufacturing process of the secondary battery, there is an injection process in which the electrolytic solution is injected into the battery case accommodating the electrode body. In this injection step, the electrolytic solution is injected into the battery case from the electrolytic solution injection nozzle connected to the injection hole provided in the lid of the secondary battery. Thereafter, the injection hole into which the electrolytic solution is injected is sealed with a sealing material to seal the secondary battery. Patent Document 1 describes an example of such a secondary battery.

  The secondary battery described in Patent Document 1 includes a metal battery case containing battery components, an injection hole for injecting an electrolyte, and a lid plate for sealing the opening of the battery case, and an injection hole. And a sealing material to be sealed. The cover plate is formed such that the entire circumference in the vicinity of the injection hole is thinner than the outer peripheral portion in the vicinity thereof. In the secondary battery, after the electrolytic solution is injected, the injection hole is sealed by the sealing material by melting the thin portion of the cover plate and the sealing material.

JP 2004-259584 A

  By the way, according to the secondary battery described in Patent Document 1, when welding the sealing material to the injection hole, the temperature of the injection hole is raised to the temperature at which the metal which is the material is melted, and accordingly, The temperature also rises around it, and it can not be avoided that the electrolyte is vaporized at all. Therefore, for example, the electrolytic solution remaining in the injection hole or the component thereof may be vaporized by heating to cause welding defects such as holes, cavities, unevenness in thickness, etc. in the fusion portion with the sealing material. is there. In addition, evaporation of the electrolyte around the injection hole raises the internal pressure in the battery case, and this air may be ejected from the welding portion to cause welding defects.

  This invention is made in view of such a situation, The objective is manufacture of the secondary battery which can suppress generation | occurrence | production of the welding defect between the injection hole of a secondary battery, and a sealing material. Abstract: A method and a secondary battery are provided.

  A method of manufacturing a secondary battery that solves the above-mentioned problems is a method of manufacturing a secondary battery in which a secondary battery in which a power generation element is housed in a battery case consisting of a battery case and a lid is provided. Heating the sealing material for sealing the injection hole having the through hole provided in the above, and the electrolyte heated in the heating step after the electrolytic solution is injected into the battery case through the injection hole A mounting step of mounting a sealing material on a sealing material mounting portion provided around the through hole, and removing the electrolytic solution attached to the sealing material mounting portion by the heat of the sealing material And welding the sealing material to the injection hole.

  When the electrolytic solution is injected into the battery case, it is inevitable that the electrolytic solution adheres to the injection hole. However, the electrolytic solution adhering to the injection hole may be vaporized during welding of the sealing material to cause welding defects. Therefore, according to such a method, by placing the heated sealing material on the sealing material placement portion of the injection hole prior to welding, the sealing material adheres to the portion to be welded by the heat of the sealing material. The electrolytic solution can be vaporized beforehand. Thereby, generation | occurrence | production of the welding defect between the injection hole of a secondary battery and a sealing material can be suppressed.

As a preferred method, the sealing material has one or more vents, and after the welding step, the step of closing the vents.
When welding the sealing material, the temperature of the injection hole and its periphery rises, the electrolytic solution is vaporized, and this is discharged from the injection hole. Therefore, according to such a method, since the electrolytic solution vaporized during welding is discharged from the vent, generation of pores, spaces and the like by the gas of the electrolytic solution vaporized to the melted portion is suppressed. Ru.

  As a preferable method, the injection hole includes an annular intermediate portion between the through hole and the sealing material placement portion, and the vent hole is provided at a position facing the intermediate portion, and the vent hole is provided. In the step of closing the air hole, the air hole is closed by laser welding by irradiating the air hole with the laser beam for welding so that the laser light for welding which has passed through the air hole is irradiated to the intermediate portion.

According to such a method, when sealing the vent, it is possible to prevent the laser light from being irradiated to the power generation element in the battery through the through hole.
As a preferable method, the sealing material is provided with an inclined surface which is recessed toward the air hole of the sealing material, and in the placing step, the inclined surface of the sealing material is made to face the injection hole and the sealing is performed. A stopper is placed in the injection hole.

  According to such a method, the vaporized gas is introduced to the vent along the inclined surface, so that the gas of the vaporized electrolyte is preferably discharged even if the vaporization of the electrolyte is rapid. To be done.

As a preferable method, the secondary battery is a lithium ion secondary battery, and in the heating step, the sealing material is heated to 90 ° C. or more.
According to such a method, it is possible to vaporize at least a part of the components of the electrolytic solution of the lithium ion secondary battery. Note that the sealing material can be heated to a temperature at which it does not melt, and for example, if it is a metal material containing aluminum as its main component, it can be heated to the melting point of aluminum (660 ° C. or less).

  The secondary battery which solves the said subject is a secondary battery which accommodates an electric power generation element in the battery case which consists of a battery case and a cover body, Comprising: The said cover body is the injection which injects electrolyte solution in the said battery case It has a hole, and the injection hole has a penetration hole which penetrates to a battery case in the center, and a sealing material placement part by which a sealing material is laid in the perimeter of the penetration hole, and the injection hole The sealing material for sealing the injection hole is welded, the sealing material includes a vent that penetrates the sealing material, and the vent is sealed.

  According to such a configuration, when sealing the sealing material in the injection hole, it is possible to discharge the gas of the electrolytic solution vaporized in the injection hole or lid heated by welding of the sealing material from the pores. . Therefore, defects in welding can be suppressed.

  As a preferable configuration, the sealing material includes an inclined surface recessed toward the vent hole on the inner side surface facing the injection hole, and an annular contact surface on the inner side surface in surface contact with the sealing material placement portion. Equipped with

  According to such a configuration, surface contact between the sealing material placement portion and the contact surface makes it easy for the heat of the sealing material to be transmitted to the sealing material placement portion, and the heat remains in the sealing material placement portion. Preferably, the vaporization of the electrolyte solution is made to make welding preferable.

Further, since the vaporized gas is guided to the vent along the inclined surface, the vaporized electrolyte is preferably discharged even if the vaporization of the electrolyte is rapid.
As a preferable configuration, the injection hole further includes an annular intermediate portion between the through hole and the sealing material placement portion, and the sealing material is disposed at a position where the vent hole faces the intermediate portion. It is provided.

According to such a configuration, when the vent is sealed by laser welding or the like, it is possible to prevent the laser light or the like from being irradiated to the power generation element inside the battery.
Preferably, the sealing material comprises two semicircular members covering the injection hole, and the two semicircular members are disposed with their arcs facing each other, and the two arcs are disposed. Each of the portions has an overhang portion overlapping the other arc in the thickness direction of the sealing material, and the overlap of the overhang portions is the vent.

  According to such a configuration, when the vent is sealed by laser welding or the like, it is possible to prevent the laser light or the like from being irradiated to the power generation element inside the battery.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the welding defect between the injection hole of a secondary battery and a sealing material can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows the general | schematic perspective view structure about one Embodiment of a secondary battery. Sectional drawing which shows the expanded cross-section of the injection hole in the embodiment. Sectional drawing which shows the cross-section which the sealing material is arrange | positioned to the injection hole in the same embodiment, and the bottom view which shows the bottom face structure of a sealing material. The flowchart which shows the process sequence of the process which seals an injection hole in the embodiment. Sectional drawing which shows the cross-section in which the sealing material is arrange | positioned at the injection hole about the other embodiment of a secondary battery, and the bottom view which shows the bottom face structure of a sealing material. The top view which shows the upper surface structure of the sealing material arrange | positioned at the injection hole about the other embodiment of a secondary battery, and sectional drawing which shows the cross-section which the sealing material is arrange | positioned. Sectional drawing which shows the cross-section in which the sealing material was arrange | positioned at the injection hole about the further another embodiment of the secondary battery.

  A method of manufacturing a secondary battery and an embodiment of a secondary battery will be described with reference to FIGS. 1 to 4. In the secondary battery 10 of the present embodiment, a plurality of external terminals 13 are connected by bus bars to configure a battery pack. The assembled battery is mounted on an electric car or a hybrid car, and supplies power to an electric motor and the like. The secondary battery 10 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, and is a sealed battery having a rectangular parallelepiped outer shape.

  As shown in FIG. 1, the secondary battery 10 has a rectangular parallelepiped battery case 11 having an opening, a lid 12 for sealing the opening of the battery case 11, and a pole housed inside the battery case 11. The plate group 17 and the electrolytic solution 75 (see FIG. 2) are provided. The battery case 11 and the lid 12 are made of a metal material mainly composed of aluminum. The secondary battery 10 has a battery case sealed by attaching the lid 12 to the battery case 11 by welding. In the secondary battery 10, the two external terminals 13 used for charge and discharge of electric power, the safety valve 14, and the electrolyte solution 75 into the battery case are injected into the outer surface 2a of the lid 12 (see FIG. 2). And the injection hole 15 to be In addition, the injection hole 15 shown in FIG. 1 has shown the state to which the sealing material 30 which seals the opening of the injection hole 15 is welded. The sealing material 30 is also made of a metal material whose main component is aluminum.

FIG. 2 shows the injection hole 15 before the sealing material 30 is welded.
The injection hole 15 is provided as a hole penetrating from the inner surface 2 b to the outer surface 2 a in the lid 12. The injection hole 15 is one step lower than the outer surface 2 a of the lid 12 so as to surround the through hole 5 c which is a circular hole penetrating to the lid 12 and the through hole 5 c (in the thickness direction of the sealing member 30 And a mounting stage 5a as a sealing material mounting portion which is recessed. Further, the injection hole 15 is formed between the through hole 5c and the mounting stage 5a as an intermediate step 5b as an annular middle portion which is one step lower than the mounting stage 5a (recessed in the thickness direction of the sealing material 30). Prepare. The through hole 5c is a hole of radius P3 with respect to the center P0 of the through hole 5c, the intermediate stage 5b is between the radius P3 and the radius P2, and the mounting stage 5a is from the radius P2 to the radius P1. In between.

  The mounting stage 5 a is a portion on which the sealing material 30 is mounted and to which the sealing material 30 is welded. The middle stage 5b is a portion with which the seal portion 7A of the injection nozzle 7 of the electrolyte solution 75 is fitted when the electrolyte solution 75 is injected into the battery case. The liquid injection portion 7B of the injection nozzle 7 of the electrolytic solution 75 enters the through hole 5c, and the electrolytic solution 75 is injected from the liquid injection portion 7B.

The upper view of FIG. 3 is a cross-sectional view of the injection hole 15 on which the sealing material 30 is placed, and the lower view is a plan view of the sealing material 30 viewed from an inner surface 30b as an inner side surface.
As shown in FIG. 3, the sealing material 30 has a circular shape that can be placed on the mounting stage 5 a formed in the injection hole 15, and the circular radius P <b> 11 is smaller than the radius P <b> 1 of the injection hole 15. A weldable groove 35 is formed by laser welding between the inner periphery of the injection hole 15 located at the radius P1 and the outer periphery of the sealing material 30 located at the radius P11.

  The sealing material 30 includes an outer surface 30a facing the battery outer side and an inner surface 30b facing the battery inner side. Moreover, the sealing material 30 is equipped with the vent 33 which penetrates the outer surface 30a and the inner surface 30b (penetrates in the thickness direction of the sealing material 30). The vent 33 has a radius P13 and is provided at the center of the sealing material 30. The sealing material 30 is provided with a seating portion 31 as an annular contact surface that abuts on the mounting stage 5a. The seating portion 31 is provided between the radius P12 and the radius P11 near the outer periphery of the inner surface 30b. The seating portion 31 has a surface parallel to the placement stage 5a, and abuts on the placement stage 5a by surface contact. For example, the parallel plane is a plane parallel to the outer surface 30a. The sealing material 30 has an inclined surface 32 between the seating portion 31 of the inner surface 30 b and the vent 33. The inclined surface 32 is provided in a shape recessed from the seating portion 31 toward the vent 33 with respect to the inner surface 30 b. In other words, the inclined surface 32 has an inclination in which the thickness in the thickness direction in the inner peripheral (radius P13) portion is thinner than the thickness in the thickness direction in the outer peripheral (radius P12) portion, The inner peripheral surface is tapered from the radius P12 toward the radius P13.

(Function of secondary battery)
That is, in the secondary battery 10 of the present embodiment, the battery case 11 is sealed by the lid 12, and the sealing material 30 is welded and sealed in the injection hole 15 of the lid 12. That is, the outer periphery of the sealing material 30 is laser welded to the inner periphery at the radius P1 of the injection hole 15. Further, in the sealing material 30, the vent 33 is sealed by laser welding. The outer periphery of the sealing material 30 is laser-welded on the outer periphery prior to the air holes 33. When laser welding is performed, the gas generated due to the component of the electrolytic solution 75 generated by heat in laser welding is It will be released from the vent 33. In addition, the inclined surface 32 can smoothly flow the gas pressurized to the sealing material 30 toward the air holes 33. Moreover, the secondary battery 10 of the present embodiment is placed in the injection hole 15 after the sealing material 30 is heated to a high temperature of 90 ° C. or higher. Thereby, the mounting stage 5a is heated by the seating portion 31 of the sealing material 30, and the component of the electrolytic solution 75 remaining there is removed by evaporation. That is, the components of the electrolytic solution 75 of the mounting stage 5a are removed prior to the laser welding. The components of the electrolytic solution 75 vaporized at this time are led to the vent 33 along the inclined surface 32. Thus, since the sealing material 30 is subjected to laser welding after the components of the electrolytic solution 75 have been removed, the components of the electrolytic solution 75 vaporized during laser welding cause unevenness, holes, cavities, etc. in the molten pool, and welding defects occur. Risk of occurrence of

(Function of manufacturing method of secondary battery)
A method of manufacturing the secondary battery of the present embodiment will be described with reference to FIG. Here, in particular, the step of sealing the injection hole 15 with the sealing material 30 will be described.

  First, prior to the sealing step being performed, the battery case 11 is sealed with the lid 12 and then the injection nozzle 7 is attached to the injection hole 15 of the lid 12, and the through hole 5 c of the injection hole 15 There is a liquid injection process in which the electrolytic solution 75 is injected into the battery case 11 through the

  Here, referring to FIG. 2, in the liquid injection step, when the electrolytic solution 75 is injected, the seal portion 7A of the injection nozzle 7 is fitted to the intermediate stage 5b, but the seal portion 7A and the intermediate stage 5b It is inevitable that the electrolyte solution 75 infiltrates in between. In addition, the electrolyte solution 75 which has infiltrated into the space between the seal portion 7A and the intermediate stage 5b often spreads to the intermediate stage 5b. That is, the electrolytic solution 75 adheres to the intermediate stage 5b, and often remains. Further, since the components of the electrolytic solution 75 include those that are vaporized when heated to high temperature, the electrolytic solution 75 is heated and vaporized by the heat when welding the sealing material 30 to the injection hole 15, and holes and cavities are formed in the welding portion There is a risk of forming unevenness in thickness. For example, gas escapes from the molten pool of aluminum heated by laser light to form a hole, enters into the molten pool to form a cavity, or presses the molten pool to form a thin portion corresponding to the inflow of gas. There is a risk of solidification as it is.

  Further, when laser welding is performed, the temperature at which aluminum is melted at the welding portion is raised, so the temperature around the injection hole 15 is also raised in the lid 12 integral with the melting portion, and the components of the electrolytic solution 75 are vaporized. For example, there is a possibility that the electrolytic solution 75 adhering to the back side of the lid 12 may be dispersed by being scattered in the battery case. Since the electrolytic solution 75 vaporized in this way is also discharged from the injection hole 15, there is a possibility that gas leakage holes, cavities, and thickness unevenness may occur in the molten pool during laser welding, and solidify as it is.

  So, in this embodiment, the sealing process which can suppress generation | occurrence | production of the welding defect between the injection hole 15 of the secondary battery 10 and the sealing material 30 is performed. In the method of manufacturing the secondary battery, when the sealing step is started, the sealing material heating process (step S10) as the heating process, the sealing material placement process (step S11) as the mounting process, the welding process The manufacturing process is performed in the order of the sealing material welding process (step S12) and the vent sealing process (step S13).

  The sealing material heating process (step S10) is a process of heating the sealing material 30 to a predetermined temperature. The predetermined temperature is a temperature at which the lowest temperature can vaporize at least one or more of the components of the electrolytic solution 75, and the highest temperature is a temperature at which the shape can be handled while maintaining the shape of the sealing material 30. It is below. For example, it is preferable to set a predetermined temperature from this range by setting the minimum temperature to 90 ° C. or higher and the maximum temperature to the melting point of aluminum (660 ° C.) or lower. As such a range, there is, for example, a range of 400 ° C. or less which is hard to cause heat deterioration in aluminum. The sealing material 30 is placed in an oven, electromagnetically heated, mechanically vibrated, or heated by a known method.

  The sealing material placement process (step S11) is a process of disposing the heated sealing material 30 in the injection hole 15 while the temperature thereof is high. The sealing member 30 disposed in the injection hole 15 raises the temperature of the mounting stage 5a by the seating portion 31 coming into contact with the mounting stage 5a, and the sealing material 30 attached to the mounting stage 5a Vaporize at least a portion of the components. As a result, the components of the electrolytic solution 75 adhering to the mounting stage 5a are eliminated or reduced, so that the components of the electrolytic solution 75 are vaporized during welding, and the vaporized gas is sealed with the injection holes 15 The possibility of causing a welding defect with the stopper 30 is suppressed. At this time, the inclined surface 32 of the sealing material 30 is opposed to the injection hole 15 so that the sealing material 30 is disposed in the injection hole 15 in order to guide the gas to the vent 33. Do.

  In addition, the temperature of the sealing material 30 is also raised around the injection holes 15 to vaporize the components of the electrolytic solution 75. As a result, it is expected that the components of the electrolytic solution 75 adhering to the periphery of the lid 12, in particular, around the injection hole 15, to be heated by the transfer of heat at the time of welding are also vaporized. That is, the reduction of the gas discharged from the injection hole 15 at the time of welding is expected, and the possibility of the occurrence of welding defects between the injection hole 15 and the sealing material 30 is suppressed.

  The sealing material welding process (step S12) is a process of laser welding the sealing material 30 disposed in the injection hole 15 to the injection hole 15. In laser welding, laser light is applied to the grooves 35 around the sealing material 30. Then, the inner periphery and mounting stage 5a at the radius P1 of the injection hole 15 and the outer periphery of the sealing material 30 and the seating portion 31 mutually melt and mix to form a molten pool. Then, the molten pool is solidified to weld the injection hole 15 and the sealing material 30. At this time, if the components of the electrolytic solution 75 remaining in the mounting stage 5a are vaporized by heating and gas is generated, there is a possibility that holes, cavities and unevenness in the thickness direction may be generated in the molten pool. In addition, if spattering of molten metal occurs due to rapid vaporization, the amount of metal in the molten pool may decrease. This may cause the above-described welding failure. However, in the present embodiment, since at least a part of the components of the electrolytic solution 75 is vaporized by placing the sealing material 30 heated in advance in the injection hole 15, sealing with the injection hole 15 is performed. In the laser welding with the material 30, the possibility of the occurrence of welding defects caused by the vaporization of the components of the electrolytic solution 75 is suppressed.

  Further, in the present embodiment, the vent 33 is open. Therefore, even if the component of the electrolyte solution 75 is vaporized by the temperature rise around the injection hole 15 and a gas is generated during the laser welding, the generated gas passes through the air hole 33 instead of the molten pool at the welding point. As a result, the generation of welding defects caused by the generation of gas is suppressed. Further, since the sealing material 30 is provided with the inclined surface 32 directed to the air vent 33, the gas directed to the injection hole 15 is also guided to the air vent 33 along the inclined surface 32 in the sealing material 30. Become.

  The vent sealing process (step S13) is a process for sealing the vent 33 of the sealing material 30 by laser welding. The secondary battery 10 is sealed by sealing the vent 33 here.

As described above, according to the method for manufacturing a secondary battery of the present embodiment and the secondary battery, the effects described below can be obtained.
(1) Prior to welding, the heated sealing material 30 is placed on the mounting stage 5 a of the injection hole 15 so that the electrolytic solution 75 adhering to the portion to be welded by the heat of the sealing material 30 is Pre-vaporize. As a result, the occurrence of welding defects between the injection holes 15 of the secondary battery 10 and the sealing material 30 can be suppressed.

(2) Since the electrolytic solution 75 vaporized during welding is discharged from the vent 33, the gas of the electrolytic solution 75 vaporized in the melted portion suppresses the generation of pores, spaces and the like.
(3) Since the vaporized gas is introduced to the vent 33 along the inclined surface 32, even if the vaporization of the electrolyte solution 75 is rapid, the gas of the vaporized electrolyte solution 75 is preferably discharged. To be done.

  (4) At least a part of the components of the electrolytic solution 75 of the lithium ion secondary battery can be vaporized. Note that the sealing material can be heated to a temperature at which it does not melt, and, for example, a metal material containing aluminum as its main component can be heated to 660 ° C.

  (5) When sealing the sealing material 30 in the injection hole 15, the gas of the electrolytic solution 75 vaporized by the injection hole 15 heated by welding of the sealing material 30 and the lid 12 is discharged from the air hole 33 be able to.

Further, since the vaporized gas is guided to the vent 33 along the inclined surface 32, even if the vaporization of the electrolyte solution 75 is rapid, the vaporized electrolyte solution 75 is suitably discharged.
(6) The surface contact between the mounting stage 5a and the seating portion 31 facilitates the heat of the sealing material 30 to be transferred to the mounting stage 5a, and the vaporization of the electrolyte solution 75 remaining in the mounting stage 5a is preferable. And the welding is preferably done.

(Other embodiments)
In addition, the said embodiment can also be implemented with the following forms.
-In the said embodiment, it illustrated about the case where the lid 12 and the sealing material 30 are the metal materials which have aluminum as a main component. However, the present invention is not limited to this, and as long as the lid and the sealing material are made of a material that can be welded, they may be made of a metal material that is not aluminum as a main component, or made of a resin material It may be done. As a result, the component of the electrolytic solution is vaporized due to the temperature rise at the time of welding, and it is possible to suppress the possibility that holes, cavities, or unevenness in thickness may be generated in the molten material.

In the above embodiment, the case where the number of the vent holes 33 of the sealing material 30 is one at the center is exemplified, but the arrangement of the vent holes is not limited to this.
An example is described with reference to FIG. The upper view of FIG. 5 is a cross-sectional view of the injection hole 15 on which the sealing material 40 is placed, and the lower view is a plan view of the sealing material 40 as viewed from the inner surface 40b.

  As shown in FIG. 5, from the inner surface 40 b to the outer surface 40 a on the circumference at a position offset from the center P 0 of the sealing material 40 having the radius P 21 and at the radius P 23 that is inside the seating portion 41. Two arc-shaped air vents 44 may be provided circumferentially spaced apart and penetrating up to the end. By making the vent hole 44 into an arc shape having a width of the radius P22 and the radius P23, the width can be narrowed, so it becomes easy to close by laser welding. On the other hand, by making the vent holes 44 arc-shaped, the length can be secured and the opening area can be increased. Therefore, the gas resulting from the component of the electrolytic solution generated when the groove 45 between the injection hole 15 and the sealing material 40 is laser-welded is suitably discharged from the air hole 44.

  Further, as shown in FIG. 5, a circumference having a radius P23 which is a position shifted from the center P0 may be provided at a position facing the intermediate step 5b. That is, the vent hole 44 may be provided at a position facing the intermediate step 5b. When the vent hole 44 is opposed to the intermediate step 5 b, the risk of the laser light being irradiated to the power generation element in the battery through the through hole 5 c is reduced when the vent hole 44 is sealed by laser welding. Specifically, the laser beam for welding is irradiated to the air hole 44 so that the laser beam for welding passing through the air hole 44 is irradiated to the intermediate stage 5 b so that the air hole 44 is closed by the laser welding do it.

  Also, at this time, the inner surface 40 b may have an outer inclined surface 42 facing the air vent 44 and an inner inclined surface 43. That is, the outer inclined surface 42 has a shape in which the thickness of the sealing material 40 decreases toward the air hole 44, and the inner inclined surface 43 has the thickness of the sealing material 40 at the center P0. It has a shape which becomes thinner toward the pores 44. In addition, even if the outer side inclined surface 42 and the inner side inclined surface 43 are not provided, or any one may be provided.

Also, an example will be described with reference to FIG. The upper view of FIG. 6 is a cross-sectional view of the injection hole 15 on which the sealing material 50 is placed, and the lower view is a plan view of the sealing material 50 viewed from the inner surface 50b.
As shown in FIG. 6, the sealing material 50 of radius P31 covers the injection hole 15 with two semicircular members 51 and 52. The two semicircular members 51, 52 are arranged in the injection hole 15 with their arc parts facing each other. The two arc portions have overhang portions 51a and 52a overlapping with the other arc portion in the thickness direction of the sealing material 50, and the overlapping portions of the overhang portions 51a and 52a are from the inner surface 50b to the outer surface 50a. It becomes an air vent 53 penetrating to the end. The overhanging portions 51a and 52a function as vents 53 for the passage of gas only when they overlap.

  Specifically, the overhanging portions 51a and 52a overlap in the thickness direction at the center P0. Specifically, the overhanging portion 51a projects a distance P33 in a direction perpendicular to the chord on the inner surface 50b, and the overhanging portion 52a projects a distance P33 in a direction perpendicular to the chord on the outer surface 50a. Then, by facing the end face of the overhanging portions 51a and 52a which are receded from the center P0 by the distance P32 in the direction perpendicular to the chord, from the inner surface 50b in the thickness direction of the sealing material 50 to the outer surface 50a. Overlap in the direction to go. And, when the air vent 53 on the outer surface 50a side, that is, the grooves 55 of the two semicircular members 51 and 52 are laser welded, transmission of laser light may be prevented and the power generation element may be irradiated. Is suppressed.

  -In addition, in the case of the sealing material 50 like FIG. 6, welding of the circumference | surroundings of the sealing material 50 and welding of the vent hole 53 can be performed continuously. For example, the laser welding apparatus is moved in the direction of the arrow M1 to start irradiating the laser light to the groove 55 between the injection hole 15 and the sealing material 50, which is a position past the air hole 53. Thereafter, the laser beam is moved along the groove 55 in the directions of the arrows M2 and M3. Then, when approaching the position where the laser light has started to be irradiated, the irradiation direction is changed from the groove 55 to the direction of the vent hole 53 as shown by the arrow M4, and the vent hole 53 is welded. Thereby, since welding of the vent hole 53 is continuously performed following welding of the circumference | surroundings of the sealing material 50, the effort concerning laser welding is reduced.

  In the above embodiment, the seating portion 31 is illustrated as being in surface contact with the placement stage 5a. However, the invention is not limited thereto. If the seating portion is supported by the placement stage, the surface contact does not occur. It is also good. For example, the placement stage may have an inclination, and the seating portion and the placement stage may be in line contact, or the seating portion may be supported by a plurality of convex portions provided on the placement stage.

  In the above embodiment, the injection hole 15 is illustrated as being provided with the intermediate step 5b between the mounting step 5a and the through hole 5c. However, the invention is not limited thereto, and the intermediate stage may not be provided in the injection hole as long as the placement stage and the through hole are provided. For example, if the liquid injection portion 7B of the injection nozzle 7 is inserted into the through hole and the seal portion 7A is inserted into the mounting stage for injection, the intermediate stage may not be provided. Alternatively, the injection nozzle 7 may be provided with the injection portion 7B inserted into the through hole without providing the seal portion 7A. In any case, since the component of the electrolytic solution 75 remaining in the mounting stage can be vaporized prior to welding, the influence of the vaporization of the component of the electrolytic solution 75 in welding can be suppressed.

  -Although the case where the sealing material 30 was heated to 90 degreeC or more was illustrated in the said embodiment, if it can vaporize not only this but the component of electrolyte solution, temperature of a sealing material shall be less than 90 degreeC It is also good.

  -Although the case where the maximum temperature of the sealing material 30 was 660 degrees C or less was illustrated in the said embodiment, while being able to vaporize the component of electrolyte solution, the shape of a sealing material and the shape of an injection hole are maintained. If possible, the maximum temperature of the encapsulant may be higher than 660 ° C. For example, if the encapsulant and the injection holes are made of a metallic material, the maximum temperature may be higher than 660.degree.

  On the other hand, when the sealing material and the injection hole are made of resin, the maximum temperature may be 660 ° C. or less according to the temperature at which the resin melts. If the temperature is lowered, the possibility of vaporization will increase, but the components that do not vaporize at the melting temperature of the resin will not evaporate at the time of resin welding, so if the temperature is close to the melting temperature of the resin, the components of the electrolytic solution will evaporate. It is possible to suppress welding defects resulting from the above.

  -Although the case where the sealing material 30 has one vent 33 was illustrated in the said embodiment, not only this but two vents are three or more as shown in FIG. Alternatively, there may be no vent.

  For example, as shown in FIG. 7, the sealing material 20 of radius P 41 may not be provided with a vent that penetrates from the inner surface 20 b to the outer surface 20 a. Even at this time, by placing the heated sealing material 20 in the injection hole 15 prior to welding, the components of the electrolyte solution 75 remaining in the injection hole 15, in particular, in the mounting stage 5 a are vaporized. Ru. Therefore, in the subsequent welding, the occurrence of welding defects caused by the vaporization of the components of the electrolytic solution 75 is suppressed.

  -In the said embodiment, the sealing material 30 illustrated about the case where the inclined surface 32 dented toward the vent 33 is provided in the inner surface 30b. However, not limited to this, the inner surface of the sealing material may be flat. Also by this, the gas consisting of the component of the vaporized electrolyte solution can be discharged from the pores.

  -In the said embodiment, it illustrated about the case where the intermediate step 5b of the step shape exists between the mounting stage 5a and the through-hole 5c. However, the shape of the intermediate stage is not limited to this, as long as the necessary distance and space between the mounting stage and the through hole or the necessary distance and space between the sealing material and the mounting stage can be secured. It does not have to be a letter.

  For example, as shown in FIG. 7, the mounting stage 5a and the through hole 5c may be connected by the inclined surface 5d. Also, for example, the horizontal surface of the mounting stage 5a and the vertical surface of the through hole 5c may be connected by a curved surface.

  -Although the above-mentioned embodiment illustrated about a case where welding is laser welding, not only this but welding may be electromagnetic welding and mechanical welding. In any case, the occurrence of welding defects caused by the vaporization of the components of the electrolytic solution due to the temperature rise is suppressed.

  In the above embodiment, although the case where the secondary battery 10 is a lithium ion secondary battery is illustrated, the present invention is not limited thereto, and the secondary battery may be a sealed secondary battery in which an electrolyte is injected from an injection hole. For example, a nickel hydrogen secondary battery may be used.

  -In the said embodiment, the secondary battery 10 illustrated about the case where it is used as a power supply of a motor vehicle. However, the secondary battery is not limited to this, and as long as it is used as a power source, it may be used as a power source other than an automobile, such as various moving bodies and fixed bodies.

  2a: outer surface, 2b: inner surface, 5a: mounting stage, 5b: middle stage, 5c: through hole, 5d: inclined surface, 7: injection nozzle, 7A: seal portion, 7B: liquid injection portion, 10: 2 Next battery 11 Battery case 12 Lid 13 13 External terminal 14 Safety valve 15 Injection hole 17 Electrode plate group 20 Sealing material 20a Outer surface 20b Inner surface 30 , 40, 50: Sealing material, 30a, 40a, 50a: outer surface, 30b, 40b, 50b: inner surface, 31: seating portion, 32: inclined surface, 33, 44, 53: vent hole, 35: groove, 42: outer side inclined surface, 43: inner side inclined surface, 51, 52: member, 51a, 52a: overhanging portion, 75: electrolytic solution.

Claims (9)

A method of manufacturing a secondary battery, comprising: manufacturing a secondary battery containing a power generation element in a battery case comprising a battery case and a lid;
Heating a sealing material for sealing an injection hole having a through hole provided in the lid;
After the electrolyte solution is injected into the battery case through the injection hole, the sealing material heated in the heating step is placed on a sealing material placement portion provided around the through hole, A placement step of removing the electrolytic solution attached to the encapsulant placement portion by the heat of the encapsulant;
And a welding step of welding the sealing material to the injection hole. The encapsulant has one or more vents,
The method of manufacturing a secondary battery according to claim 1, further comprising the step of closing the air vent after the welding step. The injection hole includes an annular intermediate portion between the through hole and the sealing material placement portion,
The air vent is provided at a position facing the middle portion,
In the step of closing the vent hole, the laser beam for welding is irradiated to the vent hole so that the laser beam for welding which has passed through the vent hole is irradiated to the intermediate portion. The method of manufacturing a secondary battery according to claim 2. The sealing material has an inclined surface recessed toward the vent of the sealing material,
The secondary cell according to any one of claims 1 to 3, wherein in the mounting step, the sealing material is disposed in the injection hole with the inclined surface of the sealing material facing the injection hole. Production method. The secondary battery is a lithium ion secondary battery,
The manufacturing method of the secondary battery as described in any one of Claims 1-4 which heats the said sealing material at 90 degreeC or more in the said heating process. A secondary battery in which a power generation element is accommodated in a battery case comprising a battery case and a lid,
The lid has an injection hole for injecting an electrolyte into the battery case,
The injection hole has a through hole penetrating to the battery case at the center, and a sealing material placement portion on which a sealing material is placed on the outer periphery of the through hole,
The injection hole is welded with the sealing material for sealing the injection hole,
The sealing material includes a vent that penetrates the sealing material,
The air vent is sealed secondary battery. The sealing material includes an inclined surface recessed toward the vent hole on an inner side surface facing the injection hole, and an annular contact surface on the inner side surface that contacts the sealing material placement portion. The secondary battery as described in 6. The injection hole further includes an annular intermediate portion between the through hole and the sealing material placement portion,
The secondary battery according to claim 6, wherein the sealing material is provided at a position where the vent hole faces the middle portion. The sealing material is composed of two semicircular members covering the injection hole, and the two semicircular members are disposed with their arc parts facing each other, and the two arc parts are The secondary battery according to claim 6, further comprising an overhang portion overlapping the other arc in the thickness direction of the sealing material, wherein the overlap of the overhang portions is the vent.

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