JP2014075280A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device which enables a worker to easily conduct welding work for sealing an opening and improves the productivity.SOLUTION: A secondary battery 10 includes a peripheral wall side inclined surface 13f which narrows a storage part S of a body member 13 in a direction from the exterior toward the interior of a case 11. Further, a lid member 14 includes a lid side inclined surface 14c which narrows the lid member 14 in a direction from the exterior toward the interior of the case 11. The lid member 14 is welded at a position that is spaced away from an opening end edge of the body member 13 so as to be located at the inner side of the case 11 than the opening end edge of the body member 13.

Description

  The present invention relates to a power storage device in which an electrode assembly and an electrolytic solution are housed in a housing portion of a case.

  Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. Generally, a secondary battery (power storage device) having a large capacity includes a case, and an electrode assembly and an electrolytic solution are accommodated in the case. In assembling the secondary battery, after the electrode assembly is accommodated in the main body member of the case, the lid member of the case is welded to the main body member to close the main body member. Then, after pouring electrolyte solution into the case from the liquid inlet of the lid member, the liquid inlet is sealed.

  As a welding structure which a case has, patent document 1 is mentioned, for example. As shown in FIG. 7, in the secondary battery of Patent Document 1, the first taper portion on the outer surface side of the cap plate 80 is formed on the inner peripheral surface of the electrolyte injection port 81 that is an opening formed in the cap plate 80. 81a is formed, and a second tapered portion 81b is formed on the inner surface side of the cap plate 80 from the first tapered portion 81a.

  The sealing member 83 that seals the electrolyte injection port 81 and is welded to the cap plate 80 includes a main body portion 83a whose outer peripheral surface is in close contact with the first tapered portion 81a, and an outer peripheral surface extending from the main body portion 83a. It consists of the extension part 83b closely_contact | adhered to the taper part 81b. Then, the sealing member 83 is press-fitted into the electrolytic solution injection port 81, and a welded portion 84 is formed along a boundary portion where the tip edge of the main body 83a and the opening edge of the electrolytic solution injection port 81 coincide with each other. The inlet 81 is sealed and a welded structure is formed.

Patent No. 4463512

  However, in order to form the welded portion 84 and seal the electrolyte solution injection port 81, the upper surface of the main body portion 83a and the upper surface of the cap plate 80 are positioned on the same surface, and the opening edge of the electrolyte solution injection port 81 Therefore, there is a problem that the front end edge of the sealing member 83 must be matched, and the welding operation for sealing the electrolyte injection port 81 is troublesome and the productivity of the secondary battery is low.

  An object of the present invention is to provide a power storage device that can easily perform a welding operation for sealing an opening and improve productivity.

  In order to solve the above problems, the invention according to claim 1 is characterized in that the electrode assembly and the electrolytic solution are accommodated in a housing portion of the case, and the case includes a main body member having the housing portion, and the housing portion. A lid member that closes, a pressure release structure that opens when the internal pressure of the case exceeds an open pressure, and a storage device that includes the electrolyte sealing structure in the case, wherein the case, the pressure At least one of an open structure and the sealing structure has a welded structure, and the welded structure closes the opening and is welded to the first welded member. A second welding member, the first welding member has a first inclined surface that narrows the opening as it goes from the outside of the case to the inside, and the second welding member is from the outside of the case. The second welding member is narrowed as it goes inward And the second welding member is welded to the first welding member at a position further away from the opening edge of the opening toward the inside of the case. And

  According to this, in the state where the second welding member is disposed in the opening of the first welding member, the second welding member is separated closer to the inside of the case than the opening edge of the opening. The outer peripheral edge of the welding member is disposed at a position one step below the opening edge of the opening. Then, when the first inclined surface and the second inclined surface are in contact with each other, the second welding member can be held at a position lowered by one step from the opening edge, and there is no need to position with a jig or the like. And if the outer periphery of the 2nd welding member positioned using the 1st and 2nd inclined surface is welded to a 1st inclined surface, an opening part can be sealed with a 2nd welding member. Therefore, compared with the case where the outer peripheral edge of the second welding member and the opening edge of the opening are matched and welded, and the opening is sealed, the welding operation for sealing can be easily performed. The productivity of the power storage device is improved.

  Moreover, the 1st inclined surface has stood up in the state which spreads outward from the outer periphery of the 2nd welding member. Therefore, the welding of the second welding member and the first inclined surface can be performed from above the second welding member, and the welding operation is performed as compared with the case where the welding operation is performed from the side or the lower side of the welding location. It is easy to perform a welding operation for sealing the opening, and the productivity of the power storage device is improved.

  In the case, the first welding member is the main body member, the second welding member is the lid member, and the lid member has a lid main body and a rib rising from a peripheral edge of the lid main body. And while having the said 2nd inclined surface in the outer peripheral surface of the said rib, you may have the said 1st inclined surface in the inner peripheral surface of the said main body member.

According to this, since the lid member has the rib, the outer peripheral surface and the second inclined surface of the lid member can be made large. Further, the rigidity of the lid member can be increased by the rib.
Further, in the sealing structure, the first welding member is the case having a liquid injection port as the opening, and the second welding member is a stopper for sealing the liquid injection port, and the liquid injection port Is located inside the liquid injection port forming portion of the case, has the first inclined surface in the liquid injection port forming portion and has the second inclined surface on the outer peripheral surface of the stopper, and forms the liquid injection port. The portion may include a receiving portion extending toward the liquid injection port.

  According to this, even when the stopper is disposed at the liquid inlet and the outer peripheral edge of the stopper and the first inclined surface of the liquid inlet forming portion are welded, the molten material may fall into the case. Can be received by the receiving part.

  The power storage device is a secondary battery.

  According to the present invention, a welding operation for sealing the opening can be easily performed, and productivity can be improved.

The perspective view which shows the secondary battery of embodiment. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 showing a secondary battery. FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1 showing a secondary battery. The fragmentary sectional view which shows another example of a liquid injection port. The fragmentary sectional view which shows another example of a liquid injection port. Sectional drawing which shows a pressure release port and a pressure release valve. Sectional drawing which shows background art.

Hereinafter, an embodiment in which a power storage device of the present invention is embodied in a secondary battery will be described with reference to FIGS.
As shown in FIGS. 1 and 2, in the secondary battery 10, an electrode assembly 12 and an electrolytic solution 21 are accommodated in the case 11. The case 11 includes a rectangular parallelepiped main body member 13 and a rectangular flat plate-shaped lid member 14. The main body member 13 includes a rectangular flat plate-like bottom portion 13a and a rectangular tubular peripheral wall 13b that is erected from a side edge of the bottom portion 13a. The main body member 13 has an accommodating part S surrounded by a bottom part 13a and a peripheral wall 13b on the inner side, and an opening part is constituted by the accommodating part S. The electrode assembly 12 and the electrolytic solution 21 are accommodated in the accommodating portion S.

  The lid member 14 is welded to the peripheral wall 13 b and seals the housing portion S. The case 11 has a welded structure between the main body member 13 and the lid member 14. In the case 11, the main body member 13 corresponds to a first welding member having an accommodating portion S as an opening, and the lid member 14 closes the accommodating portion S and corresponds to a second welding member welded to the main body member 13. To do. Both the main body member 13 and the lid member 14 constituting the case 11 are made of metal (for example, stainless steel or aluminum). Further, the secondary battery 10 of the present embodiment is a prismatic battery whose appearance is square. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

  A positive electrode terminal 15 and a negative electrode terminal 16 for taking out electricity from the electrode assembly 12 are electrically connected to the electrode assembly 12. The positive electrode terminal 15 and the negative electrode terminal 16 penetrate the lid member 14 and protrude out of the case 11, and the positive electrode terminal 15 and the negative electrode terminal 16 have a ring-shaped insulating ring 17 a for insulation from the case 11. Each is attached.

Next, the main body member 13 and the lid member 14 will be described in detail.
2 and 3, the peripheral wall 13b has a peripheral wall side inclined surface 13f as a first inclined surface on the inner peripheral surface on the opening side, and the peripheral wall side inclined surface 13f is a tip surface of the peripheral wall 13b. It is continuous to 13e. The peripheral wall side inclined surface 13f has a shape that narrows the opening width of the accommodating portion S from the front end surface 13e of the peripheral wall 13b toward the bottom portion 13a. Further, the peripheral wall side inclined surface 13f has a flat surface shape. The boundary portion N1 between the distal end surface 13e of the peripheral wall 13b and the peripheral wall side inclined surface 13f is the opening edge of the main body member 13, and is the position where the opening width is the widest in the accommodating portion S.

  The lid member 14 is formed into a predetermined shape by press molding. The lid member 14 has a rectangular plate-like lid body 14a, and has a square annular rib 14b that rises from an edge of the lid body 14a. As the rib 14b rises from the edge of the lid main body 14a, the interval between the opposing ribs 14b is increased. The rib 14b has a lid-side inclined surface 14c as a second inclined surface on the outer peripheral surface thereof, and the lid-side inclined surface 14c is formed from the outside of the case 11 along the direction orthogonal to the outer surface 14e of the lid body 14a. The shape is such that the lid member 14 is contracted as it goes to and the surface is flat.

  The lid member 14 is disposed in the accommodating portion S, and the lid-side inclined surface 14c is in surface contact with the peripheral wall-side inclined surface 13f. Further, the outer peripheral edge of the rib 14b is welded to the peripheral wall side inclined surface 13f. In the lid member 14, the outer peripheral edge of the rib 14 b is farther from the inside of the case 11 than the boundary portion N <b> 1 between the distal end surface 13 e of the peripheral wall 13 b and the peripheral wall side inclined surface 13 f.

  As shown in FIG. 3, the lid member 14 has a liquid injection port forming portion 39 that is recessed in a conical cylinder shape toward the main body member 13, and has a liquid injection port 30 inside the liquid injection port formation portion 39. The liquid injection port 30 has a first hole 31 that decreases in diameter as it goes from the outer surface 14e of the lid member 14 to the inner surface 14g. Further, the bottom of the liquid injection port forming portion 39 extends toward the central axis of the liquid injection port forming portion 39 from a position farthest from the inner surface 14 g of the lid member 14 in the inner peripheral surface of the liquid injection port forming portion 39. ing. The lid member 14 has a receiving portion 32 formed from the bottom of the liquid injection port forming portion 39. The liquid injection port 30 has a second hole 33 penetrating the receiving portion 32, and the second hole 33 has a smaller diameter than the first hole 31 and communicates the first hole 31 with the accommodating portion S. Let The liquid injection port 30 configured as described above is sealed by the stopper 20 welded to the liquid injection port forming part 39 (lid member 14). Therefore, the case 11 has a sealing structure for the electrolytic solution 21, and this sealing structure has a welding structure for the lid member 14 and the stopper 20. In the sealing structure, the lid member 14 (case 11) corresponds to a first welding member having a liquid injection port 30 as an opening, and the plug 20 closes the liquid injection port 30 and is welded to the lid member 14. This corresponds to the second welded member.

  The lid member 14 has a liquid inlet side inclined surface 39a as a first inclined surface on the inner peripheral surface of the liquid inlet forming portion 39, and the liquid inlet side inclined surface 39a is an outer surface 14e of the lid body 14a. It is continuous. The liquid injection side inclined surface 39a narrows the first hole 31 in the liquid injection port 30 as it goes from the outer surface 14e of the lid main body 14a to the inner surface 14g. A boundary portion N2 between the outer surface 14e of the lid body 14a and the liquid injection side inclined surface 39a is an opening edge of the liquid injection port 30, and is the outermost edge having the widest opening width in the liquid injection port 30. .

  The plug 20 has a plug-side inclined surface 20a as a second inclined surface on the outer peripheral surface thereof, and the plug-side inclined surface 20a extends from the outside of the case 11 along a direction orthogonal to the outer surface 14e of the lid member 14. The shape is such that the stopper 20 is narrowed toward the inside. Therefore, the length of the outer peripheral edge of the lid member 14 on the outer surface 14e side is longer than the length of the outer peripheral edge of the lid member 14 on the inner surface 14g side, and the area on the outer surface 14e side is the area on the inner surface 14g side. It is getting bigger.

  The stopper 20 is disposed in the first hole 31 in the liquid inlet 30, and the stopper-side inclined surface 20 a is in surface contact with the liquid inlet-side inclined surface 39 a. Further, the outer peripheral edge of the stopper 20 is welded to the liquid inlet side inclined surface 39a, and the outer peripheral edge of the stopper 20 is from a boundary portion N2 between the outer surface 14e of the lid body 14a and the liquid inlet side inclined surface 39a. Is further away from the inside of the case 11.

Next, the manufacturing method of the secondary battery 10 will be described together with the operation.
After the electrode assembly 12 is inserted into the housing portion S of the main body member 13, the lid member 14 is welded to the main body member 13 in a state where the housing portion S is closed by the lid member 14, and the housing portion S is sealed by the lid member 14. To do. Specifically, first, the lid member 14 is inserted into the accommodating portion S. Then, the lid-side inclined surface 14c comes into sliding contact with the peripheral wall-side inclined surface 13f and is dropped toward the bottom portion 13a. Since the opening width of the peripheral wall side inclined surface 13f is narrower toward the bottom 13a side of the main body member 13, the lid member 14 is positioned on the opening side of the accommodating portion S by surface contact between the peripheral wall side inclined surface 13f and the lid side inclined surface 14c. Is done. In this positioning state, the rib 14b is located away from the boundary N1 toward the inside of the case 11, and is positioned in a state where the peripheral wall side inclined surface 13f rises while widening the opening width outside the outer peripheral edge of the rib 14b. Yes. And the welding of the rib 14b of the cover member 14 and the surrounding wall side inclined surface 13f is performed from the upper direction of the rib 14b.

  Thereafter, the electrolytic solution 21 is injected into the case 11 from the injection port 30 into the accommodating portion S. Then, the stopper 20 is welded to the lid member 14, and the liquid injection port 30 is sealed with the stopper 20. First, the stopper 20 is inserted into the first hole 31 in the liquid injection port 30. Then, the stopper side inclined surface 20a is brought into sliding contact with the liquid inlet side inclined surface 39a and dropped toward the bottom portion 13a. Since the opening width of the liquid inlet side inclined surface 39a becomes narrower toward the bottom 13a side, the stopper 20 is positioned in the first hole 31 by the surface contact between the liquid inlet side inclined surface 39a and the stopper side inclined surface 20a. The In this positioning state, the stopper 20 is located at a position away from the boundary portion N2 toward the inside of the case 11, and is positioned in a state where the liquid injection side inclined surface 39a rises outside the outer peripheral edge of the stopper 20 while widening the opening width. doing. Then, the welding of the stopper 20 and the liquid inlet side inclined surface 39 a is performed from above the stopper 20. As a result, the secondary battery 10 is manufactured.

According to the above embodiment, the following effects can be obtained.
(1) The peripheral wall-side inclined surface 13f is formed on the inner peripheral surface of the peripheral wall 13b in the main body member 13, and the lid-side inclined surface 14c is formed on the outer peripheral surface of the rib 14b in the lid member 14. For this reason, in a state in which the lid member 14 is disposed on the opening side of the housing portion S, the rib 14b of the lid member 14 is farther from the inside of the case 11 than the opening edge (boundary portion N1) of the main body member 13. For this reason, the outer peripheral edge of the rib 14 b is disposed at a position one step below the opening edge of the main body member 13. And the peripheral wall side inclined surface 13f and the lid side inclined surface 14c are in surface contact, whereby the lid member 14 can be held at a position one step down from the opening edge, and there is no need to position it with a jig or the like. Therefore, if the outer peripheral edge of the rib 14b of the positioned lid member 14 is welded to the peripheral wall-side inclined surface 13f, the housing portion S can be sealed with the lid member 14. For this reason, compared with the case where the welding operation for sealing the accommodating part S by matching the outer peripheral edge of the rib 14b and the opening edge of the main body member 13 is performed, the welding operation is facilitated. Productivity is improved.

  (2) Further, on the outer side of the outer peripheral edge of the rib 14b, the peripheral wall-side inclined surface 13f rises in a state of widening the opening width. Therefore, welding of the rib 14b of the lid member 14 and the peripheral wall side inclined surface 13f can be performed from above the rib 14b. Therefore, for example, compared with the case where the lid member 14 is placed on the distal end surface 13e of the peripheral wall 13b and welding is performed from the side or the lower side of the peripheral wall 13b, the welding operation is easier to perform and it is difficult to perform the welding. It is possible to eliminate the occurrence of blowholes in the welded portion and insufficient welding.

  (3) The inlet side inclined surface 39 a is formed on the lid member 14, and the stopper side inclined surface 20 a is formed on the outer peripheral surface of the stopper 20. For this reason, in the state where the stopper 20 is disposed in the liquid inlet 30, the outer peripheral edge of the stopper 20 is farther from the inside of the case 11 than the opening edge (boundary portion N2) of the liquid inlet 30. The outer peripheral edge of the stopper 20 is arranged at a position one step down from the opening edge of the liquid injection port 30. Then, the stopper 20 inclined surface 20a of the stopper 20 and the liquid inlet side inclined surface 39a are in surface contact with each other so that the stopper 20 can be held at a position one step down from the opening edge and does not need to be positioned with a jig or the like. . Therefore, if the outer peripheral edge of the positioned stopper 20 is welded to the liquid inlet side inclined surface 39a, the liquid inlet 30 can be sealed with the stopper 20. For this reason, compared with the case where the outer peripheral edge of the stopper 20 and the opening edge of the liquid injection port 30 are matched and the welding operation for sealing the liquid injection port 30 is performed, the welding operation is easier to perform. Productivity of the battery 10 is improved.

  Further, on the outer side of the outer peripheral edge of the stopper 20, a liquid injection side inclined surface 39 a stands up in a state of widening the opening width. Therefore, the welding of the outer peripheral edge of the stopper 20 and the liquid inlet side inclined surface 39a can be performed from above the stopper 20, and the welding operation is easy to perform, and it is difficult to perform the welding. It is possible to eliminate the formation of blow holes and insufficient welding.

  (4) The rib 14b (lid side inclined surface 14c) and the liquid injection port 30 (liquid injection side inclined surface 39a) are formed at the same time as the lid member 14 is press-molded. Therefore, it is possible to easily form a configuration that facilitates the welding operation.

  (5) The liquid injection port 30 has a first hole 31 in which the stopper 20 is disposed, and a receiving portion 32 that extends from the inner periphery of the first hole 31. The receiving part 32 can receive the material melted when the lid member 14 is welded, and can prevent the molten high-temperature material from reaching the electrode assembly 12.

  (6) The liquid injection port 30 has a liquid injection port side inclined surface 39 a formed continuously from the opening edge thereof, and the liquid injection port side inclined surface 39 a is inclined toward the inside of the case 11. Therefore, the electrolyte solution 21 injected into the injection port 30 is guided toward the second hole 33 to facilitate the injection operation of the electrolyte solution 21.

(7) Since the lid member 14 has the ribs 14b, the lid side inclined surface 14c of the lid member 14 can be made large. Further, the rigidity of the lid member 14 can be increased by the ribs 14b.
In addition, you may change the said embodiment as follows.

  As shown in FIG. 4, the lid member 14 includes a liquid injection port forming portion 34 that rises in a conical cylinder shape from the inner surface 14 g side to the outer surface 14 e side, and the liquid injection is provided inside the liquid injection port formation portion 34. It may have a mouth 35. The liquid injection port 35 has a first hole 36 that increases in diameter as it rises from the outer surface 14 e of the lid member 14. Further, the bottom of the liquid injection port forming portion 34 is located on the same plane as the inner surface 14 g and the outer surface 14 e of the lid member 14 and constitutes a receiving portion 37. The liquid injection port 35 has a second hole 38 that penetrates the receiving portion 37. The second hole 38 has a smaller diameter than the first hole 36 and communicates the first hole 36 and the accommodating portion S. Let And the liquid injection port 35 is the liquid injection port side inclined surface 34a as a first inclined surface that narrows the liquid injection port 35 from the outside to the inside of the case 11 by the inner peripheral surface of the liquid injection port forming portion 34. Have On the other hand, the plug 20 has a plug-side inclined surface 20a on the outer peripheral surface as in the embodiment.

  When configured in this way, the liquid inlet forming part 34 for forming the liquid inlet 35 rises from the outer surface 14 e of the lid member 14 and does not protrude toward the accommodating part S. Therefore, the space between the inner surface 14g of the lid member 14 and the electrode assembly 12 does not have to be narrowed.

  As shown in FIG. 5, the receiving portion 32 in the embodiment may rise toward the inner surface 14 g of the lid member 14. When configured in this manner, the receiving portion 32 can reliably prevent the molten material from falling to the electrode assembly 12 side when the molten material is received when the lid member 14 is welded. .

  As shown in FIG. 6, the lid member 14 may be provided with a pressure release structure that opens when the internal pressure of the case 11 exceeds the open pressure. This pressure release structure is a pressure release port of the lid member 14. 41 and a pressure release valve 40 which is disposed in the pressure release port 41 and welded to the lid member 14. Therefore, the pressure release structure has a welded structure of the pressure release port 41 and the pressure release valve 40, the lid member 14 corresponds to a first welding member having the pressure release port 41 (opening), and the pressure release valve 40 corresponds to a second welding member that closes the pressure release port 41 and is welded to the lid member 14. The lid member 14 has an open port forming portion 42 that is recessed in a cylindrical shape toward the main body member 13, and has a pressure release port 41 inside the open port forming portion 42. The pressure release port 41 has a first hole 44 whose diameter is reduced from the outer surface 14e of the lid member 14 toward the inner surface 14g. The pressure release port 41 has a second hole 45 penetrating the bottom of the open port forming part 42. The second hole 45 has a smaller diameter than the first hole 44, and the first hole 44 and the accommodating part. Communicate with S.

  An open port side inclined surface 42a as a first inclined surface is provided on the inner peripheral surface of the open port forming portion 42, and the open port side inclined surface 42a is continuous with the outer surface 14e of the lid body 14a. The opening side inclined surface 42 a narrows the first hole 44 in the pressure release port 41 as it goes from the outside to the inside of the case 11. Further, a boundary portion N3 between the outer surface 14e of the lid body 14a and the opening-side inclined surface 42a is an opening edge of the pressure release port 41, and is the outermost edge having the widest opening width in the pressure release port 41. Yes.

  On the other hand, the pressure release valve 40 includes a plurality of grooves 40c on the outer surface 40a and the inner surface 40b, and includes a thin portion 40d in which the plate thickness is partially reduced by the grooves 40c. Thus, the pressure release valve 40 partially having the thin portion 40d is opened when the thin portion 40d is broken when the internal pressure of the case 11 exceeds the open pressure. Further, the pressure release valve 40 has a valve-side inclined surface 40f as a second inclined surface that narrows the outer peripheral surface of the pressure release valve 40 toward the inside from the outside of the case 11 on the outer peripheral surface thereof.

  When configured in this manner, in the state where the pressure release valve 40 is disposed in the pressure release port 41, the outer peripheral edge of the pressure release valve 40 is inside the case 11 with respect to the opening edge (boundary portion N <b> 3) of the pressure release port 41. Since the pressure release valve 40 is farther away, the outer peripheral edge of the pressure release valve 40 is disposed at a position one step lower than the opening edge of the pressure release port 41. The valve-side inclined surface 40f and the opening-side inclined surface 42a are in surface contact with each other, so that the pressure release valve 40 can be held at a position one step down from the opening edge, and there is no need to position with a jig or the like. Therefore, the pressure release port 41 can be sealed with the pressure release valve 40 if the outer peripheral edge of the positioned pressure release valve 40 is welded to the open side inclined surface 42a. For this reason, compared with the case where the outer periphery of the pressure release valve 40 and the opening edge of the pressure release port 41 are matched and the welding operation for sealing the pressure release port 41 is performed, the welding operation becomes easier. The productivity of the secondary battery 10 is improved.

  Further, on the outer side of the outer peripheral edge of the pressure release valve 40, an open port side inclined surface 42a rises in a state of widening the opening width. Therefore, the welding of the outer peripheral edge of the pressure release valve 40 and the open port side inclined surface 42a can be performed from above the pressure release valve 40, and the welding work is easy to perform, and the welding is difficult to perform. It is possible to reduce the occurrence of blowholes in the welded portion and insufficient welding.

  The secondary battery 10 includes a peripheral wall side inclined surface 13f of the main body member 13, a lid side inclined surface 14c of the lid member 14, an opening side inclined surface 42a of the pressure release port 41, and a valve side inclined surface 40f of the pressure release valve 40, And at least one of the stopper-side inclined surface 20a of the stopper 20 and the inlet side inclined surface 39a of the inlet 30 may be provided.

The lid member 14 does not have the ribs 14b, and the lid body 14a may be inclined to form the lid-side inclined surface 14c.
The pressure release structure and the sealing structure for the electrolyte solution 21 may be provided in the main body member 13 instead of the lid member 14. In this case, the main body member 13 having the pressure release port 41 and the liquid injection ports 30 and 35 corresponds to the first welding member, and the pressure release valve 40 and the plug 20 correspond to the second welding member.

The case 11 may be formed in a columnar shape or an elliptical columnar shape.
The present invention may be embodied as a nickel hydride secondary battery as an electricity storage device or an electric double layer capacitor.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(B) The power storage device according to claim 3, wherein the second hole has a smaller diameter than the first hole.

  DESCRIPTION OF SYMBOLS S ... Storage part as an opening part, 10 ... Secondary battery as an electrical storage apparatus, 11 ... Case, 12 ... Electrode assembly, 13 ... Main body member as 1st welding member, 13f ... Peripheral wall side as 1st inclined surface Inclined surface, 14 ... Lid member as first and second welding members, 14a ... Lid main body, 14b ... Rib, 14c ... Lid side inclined surface as second inclined surface, 20 ... Plug as second welding member, 20a ... Plug side inclined surface as second inclined surface, 21... Electrolyte, 30, 35... Injection hole as opening, 32, 37... Receiving portion, 34, 39. Liquid inlet side inclined surface as the first inclined surface, 40 ... Pressure release valve as the second welding member, 40f ... Valve side inclined surface as the second inclined surface, 41 ... Pressure release port as the opening, 42a ... The opening side inclined surface as the first inclined surface.

Claims (4)

The electrode assembly and the electrolytic solution are accommodated in the accommodating portion of the case,
The case includes a main body member having the housing portion, and a lid member that closes the housing portion,
A pressure release structure that opens when the internal pressure of the case exceeds the open pressure, and a storage device that includes the electrolyte sealing structure in the case,
At least one of the case, the pressure release structure, and the sealing structure has a welded structure,
The welding structure includes a first welding member having an opening, and a second welding member that closes the opening and is welded to the first welding member.
The first welding member has a first inclined surface that narrows the opening as it goes from the outside to the inside of the case;
The second welding member has a second inclined surface that narrows the second welding member as it goes from the outside to the inside of the case;
The power storage device, wherein the second welding member is welded to the first welding member at a position farther toward the inside of the case than the opening edge of the opening.   In the case, the first welding member is the main body member, the second welding member is the lid member, and the lid member has a lid main body and a rib rising from a peripheral edge of the lid main body, The power storage device according to claim 1, wherein the outer peripheral surface of the rib has the second inclined surface, and the inner peripheral surface of the main body member has the first inclined surface.   In the sealing structure, the first welding member is the case having a liquid injection port as the opening, the second welding member is a plug for sealing the liquid injection port, and the liquid injection port is the It is located inside the liquid inlet forming part of the case, has the first inclined surface in the liquid inlet forming part and has the second inclined surface on the outer peripheral surface of the stopper, the liquid inlet forming part is The power storage device according to claim 1, further comprising a receiving portion that extends toward the liquid injection port.   The power storage device according to any one of claims 1 to 3, wherein the power storage device is a secondary battery.