Power storage device

Abstract

To provide a power storage device in which a safety valve portion of a pressure relief type can be easily provided in a case member, regardless of the thickness and material of the case member made of metal.SOLUTION: A power storage device 1 includes: a case 10 having a case member 21 made of metal and including a valve hole 21i; a safety valve member 30 made of metal and including a safety valve portion 31 of a pressure relief type which fractures and opens when the internal pressure of the case 10 exceeds a valve opening pressure; and an annular valve fixing resin member 40 which is made of resin, and which is interposed between a hole surrounding portion 23 of the case member 21 surrounding the valve hole 21i and a peripheral portion 33 of the safety valve member 30 to be hermetically joined to these portions over the entire circumferences, thereby fixing the safety valve member 30 to the case member 21.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a power storage device provided with a pressure release type safety valve portion in a metal case member constituting a case.

Background Art

[0002] As a power storage device, a battery provided with a pressure release type safety valve portion in a metal case is known. The safety valve portion breaks and opens when the internal pressure of the case exceeds the opening pressure, and discharges the gas in the case to the outside of the case. This safety valve portion is formed by thinning a part of the case member (for example, a case lid member, etc.) by press working or forming a groove portion for cracking partially. For example, Patent Document 1 discloses a battery provided with such a safety valve portion (see FIGS. 1 and 2 of Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a part of the case member is press-worked as described above to integrally form a safety valve portion in the case member, it may be difficult to appropriately form a safety valve portion having a desired shape depending on the thickness and material of the case member. For example, as the battery is enlarged, if the thickness of the case member is increased, it may become difficult to integrally form a safety valve portion having a thickness that can obtain a desired opening pressure and a bottom thickness of the groove portion in the case member.

[0005] The present invention has been made in view of such a situation, and provides a power storage device capable of easily providing a pressure release type safety valve portion in a case member regardless of the thickness and material of the metal case member.

Means for Solving the Problems

[0006] (1) One aspect of the present invention for solving the above problems is a storage device including: a case having a metal case member including a valve hole; a metal safety valve member including a pressure release type safety valve portion that breaks and opens the valve when the internal pressure of the case exceeds the valve opening pressure; and an annular resin valve fixing resin member interposed between a peripheral portion around the hole surrounding the valve hole in the case member and a peripheral edge portion of the safety valve member, and hermetically joined to each of them over the entire circumference to fix the safety valve member to the case member.

[0007] In the above storage device, a safety valve member including a pressure release type safety valve portion that breaks and opens the valve due to an increase in the internal pressure of the case is fixed to the case member via a valve fixing resin member. The safety valve member is a separate member from the case member and is formed separately from the case member. Therefore, a safety valve member having a desired shape can be appropriately formed without being affected by the thickness and material of the case member. Then, by subsequently fixing the safety valve member to the case member via the valve fixing resin member, a safety valve portion can be easily provided in the case member.

[0008] In addition, compared with the case member made of metal, the valve fixing resin member made of resin is soft. For this reason, even when distortion occurs in the case member when forming the case using the case member, it is difficult for distortion to occur in the safety valve member connected via the valve fixing resin member. Therefore, in the above storage device, even when distortion occurs in the case member, there is little distortion in the safety valve member, and it is possible to suppress the influence on the valve opening pressure of the safety valve portion.

[0009] Note that examples of the "storage device" include secondary batteries such as lithium ion secondary batteries, sodium ion secondary batteries, and calcium ion secondary batteries, and capacitors such as lithium ion capacitors.

[0010] (2) Further, it is the power storage device described in (1), wherein the valve fixing resin member is made of a thermoplastic resin material, and the safety valve member and the valve fixing resin member form a temperature release type safety valve that opens when the resin material softens or melts due to a temperature rise of the valve fixing resin member. It is preferable to use a power storage device.

[0011] The safety valve member and the valve fixing resin member constitute a temperature release type safety valve that opens due to a temperature rise. That is, the above-described power storage device has a pressure release type safety valve portion and also has a temperature release type safety valve. Therefore, the power storage device can be made into a power storage device with higher safety.

[0012] (3) Further, it is the power storage device described in (1) or (2), wherein the peripheral portion of the hole of the case member is annular over the entire circumference of the peripheral portion of the hole, and particles derived from the metal forming the case member are connected in a bead-like manner to form a columnar shape. It is preferable to use a power storage device including a peripheral roughened portion with nanocolumns having a height of 50 nm or more standing upright, and the valve fixing resin member is filled with a resin material forming the valve fixing resin member between the standing nanocolumns and is hermetically joined to the peripheral roughened portion over the entire circumference.

[0013] In the above-described power storage device, a peripheral roughened portion at the nanolevel (nanoorder) where the above-described nanocolumns stand is provided at the peripheral portion of the hole of the case member, a resin material is filled between the standing nanocolumns, and the valve fixing resin member is hermetically joined to the peripheral roughened portion. Therefore, the sealing property and the bonding strength between the peripheral portion of the hole of the case member and the valve fixing resin member can be increased.

[0014] (4) Further, it is the power storage device described in any one of (1) to (3), wherein the peripheral edge portion of the safety valve member is annular over the entire circumference of the peripheral edge portion, and particles derived from the metal forming the safety valve member are connected in a bead-like manner to form a columnar shape. It is preferable to use a power storage device including a valve peripheral roughened portion with nanocolumns having a height of 50 nm or more standing upright, and the valve fixing resin member is filled with a resin material forming the valve fixing resin member between the standing nanocolumns and is hermetically joined to the valve peripheral roughened portion over the entire circumference.

[0015] In the above-described power storage device, a valve peripheral roughened portion at the nanolevel where the above-described nanocolumns stand is provided at the peripheral edge of the safety valve member, and a resin material is filled between the standing nanocolumns, and a valve fixing resin member is hermetically joined to the valve peripheral roughened portion. Therefore, the sealing performance and the joining strength between the peripheral edge of the safety valve member and the valve fixing resin member can be enhanced.

[0016] (5) Furthermore, it is a power storage device according to any one of (1) to (4), and it is preferable that the safety valve member is made of an aluminum plate having a thickness of 500 μm or less, and the safety valve portion is a power storage device formed by press molding.

[0017] Since the safety valve member uses a thin aluminum plate having a thickness of 500 μm or less, the safety valve portion can be formed by press molding easily and with high precision. Therefore, the above-described power storage device can be a power storage device provided with a safety valve member in which the opening pressure of the safety valve portion is particularly stable.

[0018] (6) Furthermore, it is a power storage device according to (5), and it is preferable that the case member is a power storage device made of an aluminum plate having a thickness of 600 μm or more.

[0019] In the conventional form in which a part of the case member is press-processed to integrally form the safety valve portion on the case member, when the thickness of the case member made of aluminum is increased to 600 μm or more, it may be difficult to integrally press-mold the safety valve portion on the case member. On the other hand, in the above-described power storage device, since the case member and the safety valve member are separate members, the safety valve portion can be press-molded on the safety valve member easily and with high precision regardless of the thickness of the case member. Therefore, the above-described power storage device can be a power storage device provided with a safety valve member in which the opening pressure of the safety valve portion is particularly stable even though the case member is made of an aluminum plate having a thickness of 600 μm or more.

[0020] (7) Furthermore, it is preferable that the power storage device described in (5) be a power storage device made of a metal other than aluminum.

[0021] There may be cases where it is desired to use a case member made of a metal other than aluminum, such as stainless steel, as the case member. In contrast, in the above-described power storage device, since the case member and the safety valve member are separate members, regardless of the material of the case member, the safety valve portion can be press-molded onto the safety valve member easily and with high accuracy. Therefore, in the above-described power storage device, even though the case member is made of a metal other than aluminum, it is possible to provide a power storage device provided with a safety valve member in which the opening pressure of the safety valve portion is particularly stable.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0023] (Embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. A perspective view of the battery (power storage device) 1 of the present embodiment is shown in FIG. 1, and a partial cross-sectional view of the battery 1 is shown in FIG. 2. Further, regarding the vicinity of the safety valve portion 31 of the battery 1, a top view is shown in FIG. 3, and a cross-sectional view is shown in FIG. 4. Furthermore, an enlarged cross-sectional view of the joint portion between the hole peripheral portion 23 of the case lid member 21 (or the peripheral edge portion 33 of the safety valve member 30) and the valve fixing resin member 40 is shown in FIG. 5. In the following, the battery height direction AH, the battery width direction BH, and the battery thickness direction CH of the battery 1 are defined as the directions shown in FIGS. 1 and 2 for explanation.

[0024] The battery 1 is a rectangular (cuboid-shaped) and sealed lithium-ion secondary battery mounted on vehicles such as hybrid cars, plug-in hybrid cars, and electric vehicles. This battery 1 is composed of a metal case 10 provided with a safety valve portion 31, an electrode body 50 and an electrolytic solution 5 housed in the case 10, and positive and negative terminal members 60 fixed to the case 10 via terminal fixing resin members 70, respectively. The electrode body 50 is covered with an insulating holder 7 in the case 10. This insulating holder 7 is made of an insulating film and is in a bag shape that opens upward AH1 in the battery height direction AH.

[0025] The electrode body 50 is rectangular parallelepiped-shaped and laminated, and is formed by alternately laminating a plurality of rectangular positive electrode plates 51 and a plurality of rectangular negative electrode plates 52 in the battery thickness direction CH via a rectangular separator 53 made of a resin porous film. Among the electrode body 50, on one side BH1 in the battery width direction BH, the current collector foils of the respective positive electrode plates 51 overlap in the battery thickness direction CH to form a positive electrode current collector portion 50c. Also, among the electrode body 50, on the other side BH2 in the battery width direction BH, the current collector foils of the respective negative electrode plates 52 overlap in the battery thickness direction CH to form a negative electrode current collector portion 50d.

[0026] The case 10 is in the shape of a rectangular parallelepiped box made of metal (aluminum in this embodiment), has a bottomed rectangular tube shape with a rectangular opening 11c, and is composed of a case body member 11 that houses the electrode body 50 inside and a rectangular plate-shaped case lid member 21 that closes the opening 11c of the case body member 11. The opening 11c of the case body member 11 and the peripheral edge 21f of the case lid member 21 are airtightly welded over the entire circumference. In this embodiment, the case lid member 21 corresponds to the aforementioned "case member". The case lid member 21 is made of an aluminum plate with a thickness ta (see FIG. 4) of 600 μm or more (thickness ta = 600 μm in this embodiment). A liquid injection hole 21k is provided in the case lid member 21, and this liquid injection hole 21k is airtightly sealed with a disc-shaped sealing member 15.

[0027] Also, in the vicinity of the center in the battery width direction BH of the case lid member 21, an oval valve hole 21i is provided. An oval plate-shaped safety valve member 30 including a pressure release type safety valve portion 31 is attached to this valve hole 21i via an oval annular valve fixing resin member 40 (see FIGS. 1 to 4). That is, the valve fixing resin member 40 is interposed between the hole peripheral portion 23 that surrounds the valve hole 21i in the case lid member 21 and the peripheral edge 33 of the safety valve member 30, and is airtightly joined to the hole peripheral portion 23 and the peripheral edge 33 over the entire circumference thereof to fix the safety valve member 30 to the case lid member 21.

[0028] The safety valve member 30 is made of a metal plate (aluminum plate in this embodiment), is oval-shaped slightly smaller than the valve hole 21i, and is plate-shaped with a thickness tb of 500 μm or less (thickness tb = 80 μm in this embodiment), which is thinner than the thickness ta of the case lid member 21. The dimension in the longitudinal direction (battery width direction BH) of the safety valve member 30 is 15 mm, and the dimension in the short direction (battery thickness direction CH) is 5 mm. In this embodiment, the entire central portion of the safety valve member 30 excluding the peripheral edge 33 becomes a pressure release type safety valve portion 31 that breaks and opens when the internal pressure of the case 10 exceeds the opening pressure. This safety valve portion 31 is press-molded and has a fracture portion 32 with a predetermined shape formed by a V-shaped groove. The thickness at the bottom of the V-shaped groove of the fracture portion 32 (the thickness of the thinnest portion of the safety valve portion 31) is 50 μm.

[0029] A valve fixing resin member 40 is joined to the peripheral edge portion 33 of the safety valve member 30. Specifically, among the surfaces 33m of the peripheral edge portion 33, excluding the outer peripheral end surface, that is, the peripheral edge outer surface 33ma facing the outside (upper side AH1 in this embodiment) and the peripheral edge inner surface 33mb facing the inside (lower side AH2 in this embodiment) each have an oval annular shape over the entire circumference of the peripheral edge portion 33 and are roughened valve peripheral roughened portions 34 (first valve peripheral roughened portion 34a and second valve peripheral roughened portion 34b). The widths (sealing widths) of the first valve peripheral roughened portion 34a (peripheral edge outer surface 33ma) and the second valve peripheral roughened portion 34b (peripheral edge inner surface 33mb) are each 0.5 mm or more (0.5 mm in this embodiment).

[0030] The valve peripheral roughened portion 34 is subjected to a roughening process using a pulsed laser beam LB described later (see FIG. 7) and is a nano-level nano-roughened portion. Specifically, a large number of bowl-shaped recesses 35 having a bowl-shaped recessed diameter Da of 30 to 300 μm (approximately diameter Da = 80 μm in this embodiment) are arranged side by side while partially overlapping in the valve peripheral roughened portion 34 (see FIG. 7). In these bowl-shaped recesses 35, nano-columns 36 having a height ha of 50 nm or more (approximately height ha = 200 nm in this embodiment), in which particles 36p derived from the metal forming the safety valve member 30 are connected in a bead-like manner and form a columnar shape, stand upright (see FIGS. 5 and 7). The metal forming the safety valve member 30 is aluminum as described above, and the nano-columns 36 are made of particles 36p composed of aluminum and aluminum oxide.

[0031] Also, the valve fixing resin member 40 is joined to the periphery of the hole 23 of the case lid member 21. Specifically, among the surfaces 23m of the periphery of the hole 23, the portions excluding the inner peripheral surface of the hole, that is, the outer peripheral surface 23ma facing the outside (upper side AH1 in this embodiment) and the inner peripheral surface 23mb facing the inside (lower side AH2 in this embodiment) each have an oval annular shape over the entire circumference of the hole periphery 23 and are roughened hole periphery roughened portions 24 (first hole periphery roughened portion 24a and second hole periphery roughened portion 24b). The widths (sealing widths) of the first hole periphery roughened portion 24a (outer peripheral surface 23ma of the periphery) and the second hole periphery roughened portion 24b (inner peripheral surface 23mb of the periphery) are each 0.5 mm or more (0.5 mm in this embodiment).

[0032] Similar to the valve periphery roughened portion 34 of the safety valve member 30 described above, the hole periphery roughened portion 24 is a nano-roughened portion at the nano level. That is, the hole periphery roughened portion 24 has a large number of bowl-shaped recesses 25 (see FIG. 7), and in each bowl-shaped recess 25, particles 26p derived from the metal (specifically, aluminum) forming the case lid member 21 are connected in a bead-like manner and form columns, and nano-columns 26 with a height ha of 50 nm or more (generally a height ha = 200 nm in this embodiment) stand upright (see FIGS. 5 and 7).

[0033] The valve fixing resin member 40 is made of a thermoplastic resin material 41. This resin material 41 includes a thermoplastic main resin (polyphenylene sulfide (PPS) in this embodiment), a thermoplastic elastomer (thermoplastic polyurethane elastomer in this embodiment), and a filler (fibrous glass filler in this embodiment). The valve fixing resin member 40 is filled with the above-mentioned resin material 41 between the nano-columns 36 standing in the valve periphery roughened portion 34 of the safety valve member 30 and is joined to the valve periphery roughened portion 34 with a strong airtight joint force over the entire circumference. Also, the valve fixing resin member 40 is filled with the above-mentioned resin material 41 between the nano-columns 26 standing in the hole periphery roughened portion 24 of the case lid member 21 and is joined to the hole periphery roughened portion 24 with a strong airtight joint force over the entire circumference.

[0034] Also, the resin material 41 that forms the valve fixing resin member 40 generally softens or melts at approximately 250°C. Therefore, the valve fixing resin member 40 and the aforementioned safety valve member 30 constitute a temperature release type safety valve 45 that opens when the resin material 41 softens or melts due to the temperature rise of the valve fixing resin member 40, specifically, when the valve fixing resin member 40 reaches about 250°C.

[0035] Next, the terminal member 60 and the terminal fixing resin member 70 will be described (see FIGS. 1 and 2). In the case lid member 21, rectangular insertion holes 21h are provided near the ends on one side BH1 and the other side BH2 in the battery width direction BH, respectively. A positive terminal member 60 made of aluminum is inserted into the insertion hole 21h on one side BH1. The positive terminal fixing resin member 70 insulates between the case lid member 21 and this terminal member 60, and is hermetically joined to the case lid member 21 and the terminal member 60 to fix the terminal member 60 to the case lid member 21. A negative terminal member 60 made of copper is inserted into the insertion hole 21h on the other side BH2. The negative terminal fixing resin member 70 insulates between the case lid member 21 and this terminal member 60, and is hermetically joined to the case lid member 21 and the terminal member 60 to fix the terminal member 60 to the case lid member 21. Since the positive and negative terminal members 60 have the same form, and the positive and negative terminal fixing resin members 70 also have the same form, they will be described together below.

[0036] The terminal member 60 is formed by pressing a metal plate (aluminum plate for the positive electrode and copper plate for the negative electrode). This terminal member 60 is located on the upper side AH1 of the case lid member 21 and includes a rectangular plate-shaped terminal top plate portion 60a that extends in the battery width direction BH and the battery thickness direction CH, and a terminal extension portion 60b that extends from this terminal top plate portion 60a to the lower side AH2 in the battery height direction AH. The terminal extension portion 60b bends at the end of one side CH1 in the battery thickness direction CH of the terminal top plate portion 60a and extends to the lower side AH2, passes through the insertion hole 21h of the case lid member 21, and further penetrates the terminal fixing resin member 70 and extends to the lower side AH2. The terminal extension portion 60b of the positive electrode is welded to the positive current collector portion 50c of the electrode body 50 at the tip of the lower side AH2. On the other hand, the terminal extension portion 60b of the negative electrode is welded to the negative current collector portion 50d of the electrode body 50 at the tip of the lower side AH2.

[0037] The terminal fixing resin member 70 is made of a thermoplastic resin material 71. In this embodiment, the resin material 71 is the same as the resin material 41 that forms the valve fixing resin member 40, but the resin material 71 and the resin material 41 can also be different resin materials. The terminal fixing resin member 70 is hermetically joined to the portion of the case lid member 21 that surrounds the insertion hole 21h and is hermetically joined to the portion of the terminal member 60 near the insertion hole 21h to fix the terminal member 60 to the case lid member 21.

[0038] Although detailed description is omitted, nano roughened portions at the nano level where the aforementioned nano pillars stand are also provided at the portion of the case lid member 21 where the terminal fixing resin member 70 is joined and at the portion of the terminal member 60 where the terminal fixing resin member 70 is joined. And the resin material 71 is filled between the nano pillars standing in these nano roughened portions, and the terminal fixing resin member 70 is hermetically joined to the case lid member 21 and the terminal member 60 with a strong bonding force.

[0039] In the battery 1 of the present embodiment, a safety valve member 30 including a pressure release type safety valve portion 31 that breaks and opens due to an increase in the internal pressure of the case 10 is fixed to the case lid member 21 via a valve fixing resin member 40. The safety valve member 30 is a separate member from the case lid member 21 and is formed separately from the case lid member 21. Therefore, the safety valve member 30 having a desired shape can be appropriately formed without being affected by the thickness ta or the material of the case lid member 21. Then, by subsequently fixing the safety valve member 30 to the case lid member 21 via the valve fixing resin member 40, the safety valve portion 31 can be easily provided on the case lid member 21.

[0040] Further, compared with the case lid member 21 made of metal, the valve fixing resin member 40 made of resin is soft. For this reason, when the case 10 is formed by welding the peripheral portion 21f of the case lid member 21 to the opening 11c of the case body member 11 over the entire circumference, even when distortion occurs in the case lid member 121, the safety valve member 30 connected via the valve fixing resin member 40 is less likely to be distorted. Therefore, in the battery 1, even when distortion occurs in the case lid member 21, the safety valve member 30 has less distortion, and the influence on the opening pressure of the safety valve portion 31 can be suppressed.

[0041] Furthermore, in the present embodiment, the valve fixing resin member 40 is made of a thermoplastic resin material 41, and the safety valve member 30 and the valve fixing resin member 40 constitute a temperature release type safety valve 45 that opens due to a temperature rise. That is, the battery 1 has a pressure release type safety valve portion 31 and also has a temperature release type safety valve 45. Therefore, the battery 1 can be made into a battery with even higher safety.

[0042] Also, in the present embodiment, a nano-level hole peripheral roughened portion 24 in which nano-columns 26 stand is provided in the hole peripheral portion 23 of the case lid member 21, and the resin material 41 is filled between the standing nano-columns 26, and the valve fixing resin member 40 is hermetically joined to the hole peripheral roughened portion 24. For this reason, the sealing property and the joining strength between the hole peripheral portion 23 of the case lid member 21 and the valve fixing resin member 40 can be increased. Further, a valve peripheral roughened portion 34 at the nanolevel where nanocolumns 36 stand upright is provided at the peripheral edge portion 33 of the safety valve member 30, and a resin material 41 is filled between the standing nanocolumns 36, and a valve fixing resin member 40 is hermetically joined to the valve peripheral roughened portion 34. For this reason, the sealing performance and the joining strength between the peripheral edge portion 33 of the safety valve member 30 and the valve fixing resin member 40 can be enhanced.

[0043] Also, in the present embodiment, since the safety valve member 30 uses a thin aluminum plate with a thickness tb of 500 μm or less, the safety valve portion 31 can be formed by press molding easily and with high precision. For this reason, the battery 1 can be a battery including a safety valve member 30 in which the opening pressure of the safety valve portion 31 is particularly stable. Also, since the case lid member 21 and the safety valve member 30 are separate members, regardless of the thickness ta of the case lid member 21, the safety valve portion 31 can be press molded on the safety valve member 30 easily and with high precision. Therefore, in the battery 1, even though the case lid member 21 is made of an aluminum plate with a thickness ta of 600 μm or more, the battery can be a battery including a safety valve member 30 in which the opening pressure of the safety valve portion 31 is particularly stable.

[0044] Next, a method for manufacturing the battery 1 will be described (see FIGS. 6 and 7). First, a case lid member 21Z before roughening, a safety valve member 30Z before roughening, and positive and negative terminal members 60Z before roughening are prepared. In the safety valve member 30Z before roughening, a safety valve portion 31 including a breaking portion 32 is formed by press molding. Then, in the case roughening step S1 (see FIG. 6), among the surfaces 23m of the peripheral portion 23 of the hole of the above-described case lid member 21Z, the outer peripheral surface 23ma and the inner peripheral surface 23mb of the peripheral portion are intermittently irradiated with the pulsed laser beam LB while shifting the irradiation position, and a plurality of bowl-shaped recesses 25 in which the nanocolumns 26 stand are arranged with partial overlap to form a hole peripheral roughened portion 24 (a first hole peripheral roughened portion 24a and a second hole peripheral roughened portion 24b) (see FIG. 7). The irradiation conditions of the laser are as follows: the wavelength is 1064 nm, the peak power is 5 kW, the pulse width is 150 ns, the pitch pb is 75 μm, and the spot diameter is 80 μm. Also, the portion of the case lid member 21Z surrounding the pair of insertion holes 21h is similarly irradiated with the pulsed laser beam LB to form a nano-roughened portion.

[0045] In the portion of the case lid member 21Z irradiated with the pulsed laser beam LB, the metal (specifically, aluminum) forming the vicinity of the surface is melted and further becomes vapor. Then, when the temperature of the vapor decreases, it becomes particles 26p of aluminum and aluminum oxide and deposits on the bowl-shaped recess 25. By intermittently irradiating the pulsed laser beam LB while shifting the irradiation position, the particles 26p are deposited and bonded in a bead-like manner to form a columnar shape, and the standing nanocolumns 26 are formed (see FIGS. 5 and 7).

[0046] Separately, in the valve roughening step S2 (see FIG. 6), among the surfaces 33m of the peripheral edge portion 33 of the above-described safety valve member 30Z, the outer peripheral surface 33ma and the inner peripheral surface 33mb of the peripheral edge portion are intermittently irradiated with the pulsed laser beam LB while shifting the irradiation position, and a plurality of bowl-shaped recesses 35 in which the nanocolumns 36 stand are arranged with partial overlap to form a valve peripheral roughened portion 34 (a first valve peripheral roughened portion 34a and a second valve peripheral roughened portion 34b) (see FIG. 7). Note that the irradiation conditions of the laser on the safety valve member 30Z are the same as those in the case roughening step S1. Separately, in the terminal roughening step S3 (see FIG. 6), the pulsed laser beam LB is intermittently irradiated on predetermined portions of the above-described positive and negative terminal members 60Z while shifting the irradiation position to form a nano-roughened portion.

[0047] Next, in the resin molding step S4, using a molding die (not shown), the safety valve member 30 is disposed within the valve hole 21i of the case lid member 21, and the positive and negative terminal members 60 are inserted through the pair of insertion holes 21h of the case lid member 21. Thereafter, the molten resin of the resin materials 41, 71 is injected into each cavity (not shown), and the valve fixing resin member 40 joined to the case lid member 21 and the safety valve member 30 is insert-molded, and the pair of terminal fixing resin members 70 joined to the case lid member 21 and the positive and negative terminal members 60 are insert-molded.

[0048] Next, in the electrode body connection step S5, an electrode body 50 obtained by laminating a positive electrode plate 51, a negative electrode plate 52, and a separator 53 is prepared, and the terminal extension portion 60b of the positive terminal member 60 is ultrasonically welded to the positive current collector portion 50c of the electrode body 50. Also, the terminal extension portion 60b of the negative terminal member 60 is ultrasonically welded to the negative current collector portion 50d of the electrode body 50. Thereafter, this electrode body 50 is wrapped with the bag-shaped insulating holder 7.

[0049] Next, in the electrode body housing / case forming step S6, the case main body member 11 is prepared, the electrode body 50 covered with the above-described insulating holder 7 is inserted into the case main body member 11, and the opening 11c of the case main body member 11 is closed with the case lid member 21. Then, the opening 11c of the case main body member 11 and the peripheral edge portion 21f of the case lid member 21 are hermetically laser-welded over the entire circumference to form the case 10. Next, in the liquid injection / sealing step S7, the electrolytic solution 5 is injected into the case 10 through the liquid injection hole 21k, and the electrolytic solution 5 is impregnated into the electrode body 50. Thereafter, the liquid injection hole 21k is hermetically sealed with the sealing member 15. Next, in the initial charging / aging step S8, the battery 1 is initially charged. Thereafter, the battery 1 is allowed to stand for a predetermined time to age the battery 1. Thus, the battery 1 is completed.

[0050] (Modified form) Next, a modified form of the above embodiment will be described. Note that the description of the same parts as in the embodiment will be omitted or simplified. In the battery 1 of the embodiment, the case 10 is formed of an aluminum plate. In contrast, in the battery (power storage device) 100 of this modified form, the case 110 is formed of a stainless steel plate. That is, the case 110 is composed of a case body member 111 made of a stainless steel plate and a case lid member (case member) 121 made of a stainless steel plate. On the other hand, the safety valve member 30 having the safety valve portion 31 is the same as in the embodiment.

[0051] Also in this modified form, the case lid member 121 and the safety valve member 30 are separate members. Therefore, regardless of the material of the case lid member 121, the safety valve portion 31 can be press-formed on the safety valve member 30 easily and with high precision. Accordingly, in the battery 100, even though the case lid member 121 is made of a metal other than aluminum, a battery can be provided with a safety valve member 30 in which the opening pressure of the safety valve portion 31 is particularly stable. In addition, the same parts as in the embodiment exhibit the same operational effects in the battery 100 of this modified form.

[0052] As described above, the present invention has been described in accordance with the embodiment and the modified form. However, it goes without saying that the present invention is not limited to the embodiment and the modified form, and can be appropriately changed and applied without departing from the gist thereof.

Explanation of Reference Numerals

[0053] 1, 100 Battery (Power Storage Device) 10, 110 Case 11, 111 Case Body Member 21, 121 Case Lid Member (Case Member) 21i Valve Hole 23 Peripheral Portion of Hole 24 Roughened Portion around Hole 24a First Roughened Portion around Hole 24b Second Roughened Portion around Hole 26 Nanopillars 26p Particles 30 Safety Valve Member 31 (Pressure-release type) safety valve part 33 Peripheral part (of the safety valve member) 34 Valve peripheral roughened part 34a First valve peripheral roughened part 34b Second valve peripheral roughened part 36 Nanopillars 36p Particles 40 Valve fixing resin member 41 Resin material 45 (Temperature-release type) safety valve 50 Electrode body 60 Terminal member 70 Terminal fixing resin member ta Thickness (of the case lid member) tb Thickness (of the safety valve member) ha Height (of the nanopillars)

Claims

1. A case having a metal case member including a valve hole, A metal safety valve member including a pressure release type safety valve portion that breaks and opens when the internal pressure of the case exceeds the opening pressure, An annular resin valve fixing resin member interposed between a hole peripheral portion surrounding the valve hole in the case member and a peripheral edge portion of the safety valve member, and hermetically joined to each of them over the entire circumference to fix the safety valve member to the case member, A power storage device.

2. The power storage device according to claim 1, The valve fixing resin member is made of a thermoplastic resin material, The safety valve member and the valve fixing resin member form a temperature release type safety valve in which the resin material softens or melts and opens due to an increase in the temperature of the valve fixing resin member. A power storage device.

3. The power storage device according to claim 1 or claim 2, The hole peripheral portion of the case member, An annular portion extending over the entire circumference of the hole peripheral portion, including a hole peripheral roughened portion in which nanoparticles having a height of 50 nm or more and formed by connecting particles derived from the metal forming the case member in a bead-like manner stand in a columnar shape, The valve fixing resin member, The resin material forming the valve fixing resin member is filled between the standing nanoparticles, and is hermetically joined to the hole peripheral roughened portion over the entire circumference. A power storage device.

4. The power storage device according to claim 1 or claim 2, The peripheral edge portion of the safety valve member, An annular portion extending over the entire circumference of the peripheral edge portion, including a valve peripheral roughened portion in which nanoparticles having a height of 50 nm or more and formed by connecting particles derived from the metal forming the safety valve member in a bead-like manner stand in a columnar shape, The valve fixing resin member, The resin material forming the valve fixing resin member is filled between the standing nanoparticles, and is hermetically joined to the valve peripheral roughened portion over the entire circumference. A power storage device.

5. The power storage device according to claim 1, The safety valve member is made of an aluminum plate having a thickness of 500 μm or less, The safety valve portion is formed by press molding. A power storage device.

6. The power storage device according to claim 5, The case member is made of an aluminum plate having a thickness of 600 μm or more. A power storage device.

7. The power storage device according to claim 5, The case member is made of a metal other than aluminum. A power storage device.

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