JP6696487B2 - Power storage device - Google Patents

Description

  The present disclosure relates to a power storage device.

  Conventionally, various power storage devices have been proposed. For example, the battery described in Japanese Patent Application Laid-Open No. 11-25951 includes an electrode group, a positive electrode side current collecting comb, a negative electrode side current collecting comb, a positive electrode side electrode column, and a negative electrode side electrode column. Including.

  The electrode group includes a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators. A positive electrode tab is formed on the upper side of the positive electrode plate so as to project from the upper side. A negative electrode tab protruding from the upper side is also formed on the upper side of the negative plate.

  A plurality of slits are formed on the positive electrode side current collecting comb. A plurality of positive electrode tabs are inserted in each slit.

  The electrode column on the positive electrode side includes a base, a column portion, and a ridge. The base is formed in a plate shape. The pillar portion is formed so as to project upward from the upper surface of the base. The ridge is formed so as to protrude downward from the outer peripheral edge of the lower surface of the base. The ridge of the electrode column is welded to the current collecting comb, and the electrode column and the current collecting comb are integrated.

  Since the electrode columns are arranged on the upper surface of the current collecting comb, the lid of the storage case of the power storage device and the upper surface of the electrode group are separated from each other.

  The power storage device described in JP 2013-196959A includes an electrode body and a current collecting terminal. The electrode body includes a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators.

  A tab portion is formed on the outer peripheral edge portion of the positive electrode, and a tab portion is also formed on the outer peripheral edge portion of the negative electrode.

  The collector terminal includes a first portion and a second portion. The first portion is formed with a slit into which the tab portions are inserted. The tab portion inserted in the slit is bent along the upper surface of the first portion. The second portion is fitted into the first portion from the upper surface side of the first portion. Therefore, the tab portion is sandwiched by the first portion and the second portion.

  Since the collector terminal is formed by the first portion and the second portion arranged on the upper surface of the first portion, the lid of the housing case of the power storage device and the electrode group are separated from each other to store the second portion. It is housed in the device.

JP-A-11-25951 JP, 2013-196959, A

  In the above conventional power storage device, the upper surface of the electrode body and the lid of the housing case are spaced from each other to secure a space for arranging various members. Along with this, a dead space is generated between the electrode body and the lid, which leads to an increase in size of the power storage device.

  The present disclosure has been made in view of the above problems, and an object thereof is to provide a power storage device in which a dead space in the power storage device is reduced.

  An electricity storage device according to the present disclosure includes an electricity storage body including a plurality of stacked metal plates, a current collecting terminal welded to the electricity storage body, and a welding portion that welds the current collecting terminal and the electricity storage body. Each metal plate of the plurality of metal plates includes a metal plate body and a tab formed to project from an outer peripheral edge portion of the metal plate. The collector terminal includes a facing surface located on the power storage body side and an opposite surface located on the opposite side to the facing surface. The current collector terminal has a slit formed so as to reach the opposite surface from the opposite surface and extend in one direction and into which the tab is inserted, and a groove portion is formed on the opposite surface. When the opposite surface is viewed in plan, the slit is formed so as to pass through the groove. The tab includes a joining portion joined to the collector terminal by a welding portion and a remaining portion adjacent to the joining portion, and the remaining portion is housed in the groove.

  According to the above power storage device, the remaining portion of the tab is housed in the groove, and the remaining portion does not project upward. Therefore, the collector terminal can be brought close to the inner surface of the housing case of the power storage device. Along with this, it is possible to suppress the formation of a large dead space between the collector terminal and the housing case, and it is possible to reduce the size of the power storage device.

  The power storage device according to the present disclosure can reduce the dead space.

FIG. 3 is a perspective view showing power storage device 1 according to the present embodiment. FIG. 3 is an exploded perspective view showing power storage device 1. It is a disassembled perspective view which disassembled a part of electrode body 3. It is a perspective view which shows the tab 18 typically. It is a perspective view showing the positive electrode current collector terminal 6. It is a top view which shows the positive electrode collector terminal 6. It is sectional drawing in the VII-VII line shown in FIG. It is a perspective view in the state where the positive electrode collector terminal 6 is welded to the electrode body 3. FIG. 4 is a plan view showing a state in which the positive electrode current collector terminal 6 is welded to the electrode body 3. It is sectional drawing in the XX line in FIG. FIG. 6 is a manufacturing flow chart showing a manufacturing process of power storage device 1. It is a perspective view which shows the electrode body formation process S1. It is a perspective view showing electrode body 3 formed by electrode body formation process S1. It is a perspective view which shows the preparation process S2. It is a manufacturing flow figure showing a manufacturing process of positive electrode current collection terminal 6A. It is a perspective view showing a casting process S10. It is a perspective view showing a press working step S11. It is a perspective view showing slit formation process S12. It is a perspective view which shows the insertion process S3 typically. It is a perspective view which shows the electrode body 3 in the state shown in FIG. It is a perspective view which shows the clamping process S4 typically. It is a perspective view showing the process of narrowing the width of slits 45a-45d. It is a perspective view which shows the welding process S5 typically. It is a perspective view which shows the process of forming the welded part 8. It is a perspective view which shows typically the tab 18 in the welding process S5. It is sectional drawing which shows the structure of the welding part 8c in FIG. 24, and its periphery. It is sectional drawing which shows the structure of the protrusion part 26 shown in FIG. 24, and its circumference. It is a perspective view which shows the bending process S6 typically. It is sectional drawing which shows the structure of the protrusion part 26 shown in the figure, and its circumference. It is sectional drawing which shows the modification of the bending direction of the protrusion part 26. It is a process which shows the assembly process S7 typically. FIG. 3 is an exploded perspective view showing power storage device 1A. It is a perspective view which shows the positive electrode collector terminal 6B. It is sectional drawing which shows the positive electrode current collector terminal 6B and the structure of the circumference | surroundings. FIG. 7 is a cross-sectional view showing a power storage device 1C which is a modification of power storage device 1. It is a top view which shows the modification of the positive electrode collector terminal 6.

  A power storage device 1 according to the present embodiment will be described with reference to FIGS. 1 to 36. Of the configurations shown in FIGS. 1 to 36, the same or substantially the same configurations are denoted by the same reference numerals, and duplicate description may be omitted.

  FIG. 1 is a perspective view showing power storage device 1 according to the present embodiment, and FIG. 2 is an exploded perspective view showing power storage device 1. The power storage device 1 includes a housing case 2, an electrode body 3, a positive electrode external electrode 4, a negative electrode external electrode 5, a positive electrode current collecting terminal 6, a negative electrode current collecting terminal 7, welding parts 8 and 9, and an electrolytic solution. 10, the insulating members 70 and 71, and the sealing member 80.

  The housing case 2 includes a lid 2A and a case body 2B. The case body 2B has an opening that opens upward. The lid 2A is welded to the opening edge of the opening.

  The lid 2A and the case body 2B are made of aluminum or aluminum alloy. A through hole 80a is formed in the lid 2A, and the sealing member 80 is formed so as to close the through hole 80a.

  The positive electrode external electrode 4 and the negative electrode external electrode 5 are provided on the upper surface of the lid 2A. The positive electrode external electrode 4 and the negative electrode external electrode 5 are arranged at intervals in the width direction of the lid 2A.

  The electrode body 3, the positive electrode current collector terminal 6, the negative electrode current collector terminal 7, and the electrolytic solution 10 are housed in the housing case 2.

  The electrode body 3 is formed in a flat plate-like rectangular parallelepiped shape. The electrode body 3 includes an upper surface 20, a lower surface 21, main side surfaces 22 and 23, and end side surfaces 24 and 25.

  The electrode body 3 is formed by stacking a plurality of positive electrode sheets 11, a plurality of separators 12, and a plurality of negative electrode sheets 13. The sheets are stacked in the stacking direction SD.

  FIG. 3 is an exploded perspective view in which a part of the electrode body 3 is disassembled. The electrode body 3 is formed by sequentially stacking the positive electrode sheet 11, the separator 12, the negative electrode sheet 13, and the separator 12.

  The positive electrode sheet 11 includes a metal plate 15 and a positive electrode mixture layer 16. The metal plate 15 is made of, for example, aluminum or aluminum alloy.

  The metal plate 15 includes a metal plate body 17 and a tab 18. The metal plate body 17 is formed in a substantially rectangular shape. The positive electrode mixture layer 16 is formed on the front and back surfaces of the metal plate body 17. The positive electrode mixture layer 16 contains a positive electrode active material, a binder, and the like. The tab 18 is formed so as to project upward from the upper side of the metal plate body 17. The tab 18 is formed on the end side surface 24 side of the electrode body 3. The upper side of each metal plate 15 is formed so as to extend in the width direction W of the negative electrode external electrode 5.

  FIG. 4 is a perspective view schematically showing the tab 18. A protruding portion (residual portion) 26, a protruding portion (residual portion) 27, and a joint portion 28 are formed on the upper end side of the tab 18. The protrusion 26 and the protrusion 27 are formed with a space therebetween. The protrusion 26 and the protrusion 27 are bent from the upper end side in the stacking direction SD.

  The joint portion 28 is located between the protruding portion 26 and the protruding portion 27, and is joined to the positive electrode current collector terminal 6 by a welding portion described later.

  In FIG. 3, the negative electrode sheet 13 includes a metal plate 30 and a negative electrode mixture layer 31. The metal plate 30 is formed of copper, a copper alloy, electrolytic copper, or the like. The metal plate 30 includes a metal plate body 32 and a tab 33. The metal plate body 32 is formed in a rectangular shape. The negative electrode mixture layer 31 is formed on the front and back surfaces of the metal plate body 32. The negative electrode mixture layer 31 contains a negative electrode active material, a binder, and the like.

  The tab 33 is formed so as to project upward from the upper side of the metal plate body 32. It should be noted that the tab 33 also includes two projecting portions, like the tab 18, and a joint portion is formed between the two projecting portions.

  In FIG. 2, the positive electrode current collector terminal 6 and the negative electrode current collector terminal 7 are arranged on the upper surface 20 of the electrode body 3. The positive electrode current collecting terminal 6 is arranged below the positive electrode external electrode 4, and the negative electrode current collecting terminal 7 is arranged below the negative electrode external electrode 5.

  The welded portion 8 joins the plurality of tabs 18 of the plurality of positive electrode sheets 11 to the positive electrode current collector terminal 6, and the positive electrode current collector terminal 6 is joined to the electrode body 3 by the welded portion 8. The welded portion 9 joins the plurality of tabs of the plurality of negative electrode sheets 13 and the negative electrode collector terminal 7, and the negative electrode collector terminal 7 is joined to the electrode body 3 by the welded portion 9.

  FIG. 5 is a perspective view showing the positive electrode current collector terminal 6. Note that FIG. 5 shows a state before the positive electrode collector terminal 6 is welded to the electrode body 3.

  The positive electrode current collector terminal 6 includes a facing surface 34 and an upper surface 35. The facing surface 34 faces the upper surface 20 of the electrode body 3. The upper surface 35 is an opposite surface located on the opposite side of the facing surface 34.

  The positive electrode current collector terminal 6 includes a plate portion 40 and a connecting shaft 41. The connection shaft 41 is formed so as to project upward from the upper surface of the plate portion 40. The connection shaft 41 includes a shaft 42 and an engagement portion 43. The shaft 42 is formed so as to project upward from the upper surface 35. The engagement portion 43 is formed on the upper end of the shaft 42 and is formed so as to project horizontally from the upper end of the shaft 42.

  The plate portion 40 is formed with a plurality of slits 45a to 45d. Each of the slits 45a to 45d is formed so as to extend in the width direction W from one end of the positive electrode current collector terminal 6.

  Thereby, the plate body 40 and the plurality of legs 46a to 46e are formed in the plate portion 40. The plate body 44 is formed in a plate shape.

  Slits 45a to 45d are formed between the legs 46a to 46e. One end of each leg 46a to 46e is connected to a side portion of the plate body 44 and serves as a fixed end. The other ends of the legs 46a to 46e are free ends. The legs 46a to 46e are also formed so as to extend in the width direction W.

  FIG. 6 is a plan view showing the positive electrode current collector terminal 6. A groove 50a and a groove 51a are formed on the leg 46a. The groove portion 50a and the groove portion 51a are formed at intervals in the width direction W. The groove 50a is formed on the other end side (free end side) of the leg 46a, and the groove 51a is formed on one end side (fixed end side) of the leg 46a.

  The leg 46a includes a pedestal 52a and a pedestal 53a. The pedestal 52a is formed between one end of the leg 46a and the groove 50a. The pedestal 53a is formed between the groove 51a and the groove 50a.

  Similarly, the legs 46b, 46c, 46d and 46e are provided with groove portions 50b, 50c, 50d and 50e and groove portions 51b, 51c, 51d and 51e.

  The legs 46b, 46c, 46d, 46e include pedestals 52b, 52c, 52d, 52e and pedestals 53b, 53c, 53d, 53e. The bases 52b, 52c, 52d, 52e are formed between the other ends of the legs 46b, 46c, 46d, 46e and the groove portions 50b, 50c, 50d, 50e. The pedestals 53b, 53c, 53d, 53e are formed between the groove portions 50b, 50c, 50d, 50e and the groove portions 51b, 51c, 51d, 51e.

  The grooves 50a to 50e are arranged in the stacking direction SD, and the grooves 47 are formed by the grooves 50a to 50e.

  The grooves 51a to 51e are arranged in the stacking direction SD, and the grooves 48 are formed by the grooves 51a to 51e.

  As shown in FIG. 6, when the upper surface 35 of the positive electrode current collector terminal 6 is viewed in a plan view, the slits 45 a to 45 d are formed so as to pass through the groove portion 47 and the groove portion 48. The plan view of the upper surface 35 means viewing from a position above the upper surface 35 in a direction perpendicular to the upper surface 35.

  FIG. 7 is a sectional view taken along line VII-VII shown in FIG. The upper surfaces of the base 52c and the base 53c are located above the bottom surface of the groove 50c and the bottom surface of the groove 51c. Here, in FIGS. 6 and 7, the thickness TH of the plate body 44 and the legs 46a to 46e is, for example, 1 mm or more and 3 mm or less. This is because if it is thinner than 1 mm, it becomes difficult to secure the strength of the positive electrode current collector terminal 6. When the thickness is greater than 3 mm, the volume occupied by the positive electrode current collector terminal 6 increases. Preferably, it is about 1.5 mm. The length L2 in the stacking direction SD is about 24 mm. The length L1 of the positive electrode current collector terminal 6 in the width direction W is about 45 mm. The widths L3 and L4 of the groove portions 50a to 50e and 51a to 51e in the width direction W are, for example, about 5 mm. The width L5 of each slit 45a to 45d is, for example, about 0.8 mm. The length of the slits 45a to 45e in the width direction W is about 30 mm.

  The negative electrode current collector terminal 7 is also formed similarly to the positive electrode current collector terminal 6. For example, the thickness of the negative electrode current collector terminal 7 is, for example, about 1 mm. The length of the negative electrode current collector terminal 7 in the stacking direction SD is, for example, about 24 mm. The length of the negative electrode current collector terminal 7 in the width direction W is, for example, about 45 mm. The slits formed in the negative electrode current collector terminal 7 have the same dimensions as the slits 45 a to 45 d formed in the positive electrode current collector terminal 6.

  FIG. 8 is a perspective view showing a state in which the positive electrode collector terminal 6 is welded to the electrode body 3, and FIG. 9 is a plan view showing a state in which the positive electrode collector terminal 6 is welded to the electrode body 3. .

  A plurality of tabs 18 are inserted into each of the slits 45a to 45d. For example, 18 tabs 18 are inserted into each of the slits 45a to 45d. Each of the welded portions 8a to 8d joins the tab 18 inserted into each of the slits 45a to 45d to the positive electrode current collector terminal 6. Specifically, the joint portion 28 of each tab 18 is joined to the legs 46a to 46e by the weld portions 8a to 8d.

  The protruding portion 26 of each tab 18 is bent and arranged in the groove portions 50b to 50e. For example, 18 protrusions 26 are stacked in each groove 50b to 50e.

  The protruding portion 27 of each tab 18 is bent and arranged in each of the groove portions 51b to 51e. For example, 18 protrusions 27 are stacked in each of the grooves 51b to 51e.

  FIG. 10 is a sectional view taken along line XX in FIG. A plurality of bent protrusions 26 are stacked in the groove 50c, and a bent protrusion 27 is stacked in the groove 51c.

  The depths DP1 and DP2 of the groove portions 50a to 50e and 51a to 51e are, for example, about 0.3 mm or more and about 0.6 mm. This is because when the depth is smaller than 0.3 mm, the stacked protruding portions 26 and 27 protrude from the groove portions 50a to 50e and 51a to 51e. Further, if it is deeper than 0.6 mm, the thickness of the bottom portions of the groove portions 50a to 50e and 51a to 51e becomes thin, and the strength of the bottom portions becomes low. Preferably, the depths DP1 and DP2 are about 0.27 mm or more and 0.5 mm or less. If the thickness of each protrusion 26, 27 is, for example, 0.015 mm and the number of each protrusion 26, 27 is 18, the thickness of the stacked protrusions 26, 27 is 0.27 mm. .. Therefore, the depths DP1 and DP2 are made deeper than 0.27 mm. This is because if the depth is more than 0.5 mm, the thickness of the bottom of each groove 50a to 50e and 51a to 51e becomes thin, and the strength of the bottom becomes low.

  In this way, it is possible to suppress the protruding portions 26 and 27 stacked from the groove portions 50b to 50e and 51b to 51e from protruding.

  Returning to FIG. 2, the positive electrode external electrode 4 includes an insulating member 60, a metal plate 61, and a terminal 62. The insulating member 60 is arranged on the upper surface of the lid 2A. The metal plate 61 is arranged on the upper surface of the insulating member 60. The terminal 62 is formed so as to project upward from the end portion side of the metal plate 61. A through hole 61 a is formed in the metal plate 61. The insulating member 60 also has a through hole communicating with the through hole 61a, and the lid 2A also has a through hole communicating with the through hole.

  The negative electrode external electrode 5 is formed similarly to the positive electrode external electrode 4. The negative electrode external electrode 5 includes an insulating member 63, a metal plate 64, and a terminal 65. The insulating member 63 is arranged on the upper surface of the lid 2A. The metal plate 64 is arranged on the upper surface of the insulating member 63. The terminal 65 is formed so as to project upward from the upper surface of the metal plate 64. A through hole 64 a is formed in the metal plate 64. The insulating member 63 has a through hole communicating with the through hole 64a, and the lid 2A has a through hole communicating with the through hole.

  The insulating member 70 includes a pedestal 72 and a tubular portion 73. The pedestal 72 is arranged between the positive electrode current collector terminal 6 and the lid 2A, and the pedestal 72 ensures insulation between the positive electrode current collector terminal 6 and the lid 2A. The tubular portion 73 is inserted into a through hole formed in the lid 2A. The shaft 42 is inserted into the cylindrical portion 73.

  The engagement portion 43 is arranged on the upper surface of the metal plate 61. By engaging the engaging portion 43 with the metal plate 61, the lid 2A, the positive electrode external electrode 4, the insulating member 70, the positive electrode current collector terminal 6, and the electrode body 3 are integrally connected.

  The insulating member 71 is also formed similarly to the insulating member 70. The insulating member 71 includes a pedestal 74 and a tubular portion 75. The pedestal 74 is arranged between the lid 2A and the negative electrode current collector terminal 7. The tubular portion 75 is formed in a hollow shape, and the tubular portion 75 is inserted into a through hole formed in the lid 2A. The shaft of the negative electrode current collector terminal 7 is inserted into the tubular portion 75, and the engaging portion of the negative electrode current collector terminal 7 is engaged with the metal plate 64. Thereby, the negative electrode external electrode 5, the lid 2A, the insulating member 71, the negative electrode current collector terminal 7, and the electrode body 3 are integrally connected.

  In FIG. 10, the protruding portions 26 and 27 are housed in the groove portions 50 and 51. Therefore, the positive electrode current collector terminal 6 and the lid 2A can be brought close to each other. Similarly, the gap between the negative electrode current collector terminal 7 and the lid 2A can be kept small.

  In this way, since the positive electrode current collector terminal 6 and the negative electrode current collector terminal 7 can be brought close to the lid 2A, the space between the electrode body 3 and the lid 2A becomes small, and the dead space can be suppressed to be small. Thereby, the power storage device 1 can be downsized.

  Next, a method for manufacturing power storage device 1 configured as described above will be described. FIG. 11 is a manufacturing flow chart showing the manufacturing steps of power storage device 1. The manufacturing process of the power storage device 1 includes an electrode body forming process S1, a preparing process S2, an inserting process S3, a sandwiching process S4, a welding process S5, a bending process S6, an assembling process S7, and an injecting process S8. And a sealing step S9.

  FIG. 12 is a perspective view showing the electrode body forming step S1. FIG. 13 is a perspective view showing the electrode body 3 formed in the electrode body forming step S1. The electrode body forming step S1 is a step of sequentially laminating the positive electrode sheet 11, the separator 12, the negative electrode sheet 13, and the separator 12. For example, the number of positive electrode sheets 11 is 72, and the number of negative electrode sheets 13 is 74. In the electrode body 3 after the electrode body forming step S1, the tabs 18 and the tabs 33 are formed so as to extend upward.

  In the positive electrode sheet 11, the metal plate 15 has a thickness of, for example, about 15 μm. The length of the metal plate body 17 in the height direction H (the length from the upper end side to the lower end side of the metal plate body 17) is, for example, about 75 mm. The length of the metal plate 15 (metal plate body 17) in the width direction W is, for example, about 140 mm.

  The length of the tab 18 in the width direction W is about 20 mm. The length of the tab 18 in the height direction H is about 10 mm.

  In the negative electrode sheet 13, the metal plate 30 has a thickness of, for example, about 10 μm. The length of the metal plate body 32 in the height direction H is about 80 mm. The length of the metal plate 30 (metal plate body 32) in the width direction W is about 144 mm.

  The length of the tab 33 in the width direction W is about 20 mm. The length of the tab 33 in the height direction H is about 7 mm.

  The length of the separator 12 in the height direction H is about 84 mm. The length of the separator 12 in the width direction W is about 147 mm. The thickness of the separator 12 is about 24 μm. The tab 18 and the tab 33 protrude from the separator 12 by about 5 mm.

  FIG. 14 is a perspective view showing the preparation step S2. The preparation step S2 is a step of disposing the positive electrode current collector terminal 6A and the negative electrode current collector terminal 7A which are manufactured in advance above the electrode body 3.

  The positive electrode collector terminal 6A is not provided with the engaging portion 43 shown in FIG. Similarly, the negative electrode current collector terminal 7A has no engaging portion.

  FIG. 15 is a manufacturing flow chart showing the manufacturing process of the positive electrode current collector terminal 6A. The method for manufacturing the positive electrode current collector terminal 6A includes a casting step S10, a pressing step S11, and a slit forming step S12.

  FIG. 16 is a perspective view showing the casting step S10. The casting step S10 is a step of forming the aluminum plate 6a on which the shaft 42 is formed.

  FIG. 17 is a perspective view showing the pressing step S11. The press working step S11 is a step of forming the groove portions 47 and 48 by subjecting the aluminum plate 6a formed in the casting step S10 to press working or the like. The groove width of the groove portions 47 and 48 is about 5 mm, and the depth of the groove portions 47 and 48 is about 0.5 mm.

  FIG. 18 is a perspective view showing the slit forming step S12. The slit forming step S12 is a step of forming the slits 45a to 45d by performing laser processing, press processing, or the like on the aluminum plate having the grooves 47 and 48 formed therein. In this step, the grooves 50a to 50e and 51a to 51e are formed in the legs 46a to 46e. The manufacturing process of the negative electrode collector terminal 7A is substantially the same as the manufacturing process of the positive electrode collector terminal 6A.

  FIG. 19 is a perspective view schematically showing the inserting step S3. In the inserting step S3, the tab 18 of the electrode body 3 is inserted into the slits 45a to 45d of the positive electrode current collector terminal 6A.

  For example, about 18 tabs 18 are inserted into each of the slits 45a to 45d. The upper end of each tab 18 projects from the positive electrode collector terminal 6A by, for example, about 2 mm.

  A plurality of tabs 33 are also inserted in each slit formed in the negative electrode current collector terminal 7A. For example, when four slits are formed in the negative electrode current collector terminal 7A, for example, 19 tabs 33 are inserted into each of the two central slits. For example, 18 tabs 33 are inserted into the two slits arranged on the end side. Each tab 33 projects from the negative electrode collector terminal 7A by, for example, about 2 mm.

  20 is a perspective view showing the electrode body 3 in the state shown in FIG. As shown in FIG. 20, since a plurality of tabs 18 are inserted into the slits 45a to 45d, a plurality of bundle portions 81 are formed on the upper surface of the electrode body 3. Each bundle 81 is formed by a plurality of tabs 18.

  Similarly, a plurality of bundles 82 are formed on the negative electrode side, and each bundle 82 is formed by a plurality of tabs 33.

  FIG. 21 is a perspective view schematically showing the sandwiching step S4. The sandwiching step S4 was formed on the negative electrode current collector terminal 7A by applying an external force P1 to the positive electrode current collector terminal 6A to reduce the width of the slits 45a to 45d and by applying an external force P2 to the negative electrode current collector terminal 7A. And a step of narrowing the width of the slit.

  FIG. 22 is a perspective view showing a step of narrowing the width of the slits 45a to 45d. In this step, the external force P1 is applied to the legs 46a and 46e. As a result, the legs 46a to 46e and the tab 18 can be brought into close contact with each other.

  Also in the negative electrode current collector terminal 7A, the legs formed on the negative electrode current collector terminal 7A and the tab 33 can be brought into close contact with each other.

  FIG. 23 is a perspective view schematically showing the welding step S5. The welding step S5 includes a step of forming a welded portion 8 on the positive electrode collector terminal 6A and a step of forming a welded portion 9 on the negative electrode collector terminal 7A.

  FIG. 24 is a perspective view showing a process of forming the welded portion 8. As shown in FIG. 24, welded portions 8a to 8d are formed on the positive electrode current collector terminal 6A. Specifically, the portion of the tab 33 protruding from between the pedestals 53a to 53e is irradiated with the laser.

  At this time, in the above-mentioned sandwiching step S4, since the slit width of each slit 45a to 45d is narrowed, it is possible to prevent the laser from passing through between the legs 46a to 46e and the tab 18 toward the electrode body 3 side. .. Further, when the tab 33 and the legs 46a to 46e are irradiated with the laser, a part of the tab 33 and the legs 46a to 46e is melted. At this time, the fused portion may scatter, or a part of the tab 33 may scatter. Even if such spatter occurs, since the legs 46a to 46e and the tab 18 are in close contact with each other, it is possible to prevent the molten portion and a part of the metal plate from coming off to the electrode body 3 side.

  A fiber laser is used, for example, in the step of forming the welded portions 8a to 8d. The output of the fiber laser is 1500 W, for example. The scanning speed of the laser is, for example, 1800 mm / s. As a result, the portion of the tab 33 protruding from between the pedestals 53a to 53e is joined to the pedestals 53a to 53e.

  On the other hand, in the tab 33, the portions located in the groove portions 50a to 50e remain, and the protruding portions 26 are formed. Similarly, in the tab 33, the portions located in the groove portions 51a to 51e remain, and the protruding portions 27 are formed.

  FIG. 25 is a perspective view schematically showing the tab 18 in the welding step S5. A protrusion 26 and a protrusion 27 are formed on the upper end of the tab 18. The welded portion 8 is formed in a portion located between the protruding portion 26 and the protruding portion 27.

  FIG. 26 is a cross-sectional view showing the structure of the welded portion 8c and its surroundings in FIG. The plurality of tabs 18 are joined to the legs 46c and 46d by the weld 8c by the weld 8c.

  FIG. 27 is a cross-sectional view showing the configuration of the protruding portion 26 shown in FIG. 24 and its surroundings. The projecting portion 26 projects from the upper surfaces of the legs 46c and 46d.

  The step of forming the welded portion 9 on the negative electrode current collector terminal 7A is substantially the same as the step of forming the welded portion 8 on the positive electrode current collector terminal 6A.

  The welded portion 9 is also formed by, for example, a fiber laser. When forming the welded portion 9, the laser output is about 2500 W. The laser scanning speed is, for example, 1800 mm / s.

  FIG. 28 is a perspective view schematically showing the bending step S6. In this bending step S6, the protrusions 26 protruding from the slits 45a to 45d are bent to accommodate the plurality of protrusions 26 in the grooves 50b to 50e. Further, in the bending step S6, the protruding portion 27 protruding from the slits 45a to 45d is bent and accommodated in the groove portions 51b to 51e. A roller or the like can be used as a means for bending the protrusions 26 and 27.

  FIG. 29 is a cross-sectional view showing the configuration of the projecting portion 26 shown in the figure and its surroundings. In the example shown in FIG. 29 and the like, an example in which the projecting portion 26 is bent to one side is described, but as the direction of bending the projecting portion 26, as shown in FIG. 30, the projecting portion 26 is bent to both sides. Good.

  FIG. 31 is a step schematically showing the assembling step S7. The assembling step S7 includes a first assembling step of integrally assembling the lid 2A, the positive electrode current collecting terminal 6A, the negative electrode current collecting terminal 7A, and the electrode body 3, and a second assembling the lid 2A to the case body 2B. And an assembling step.

  The first assembly step is an insertion step of passing the shaft 42 of the positive electrode current collector terminal 6A through the tubular portion 73 of the insulating member 70, the through hole of the lid 2A, the through hole of the insulating member 60, and the through hole 61a. Including. By this insertion step, the upper end of the shaft 42 projects from the upper surface of the metal plate 61. After the inserting step, the upper end of the shaft 42 is crimped to form the engaging portion 43. Thereby, the positive electrode collector terminal 6 is formed. As a result, the positive electrode external electrode 4, the lid 2A, the positive electrode current collector terminal 6, and the electrode body 3 are integrally assembled.

  Similarly, the shaft portion of the negative electrode current collector terminal 7A is inserted into the tubular portion 75 of the insulating member 71, the through hole formed in the lid 2A, and the through hole formed in the insulating member 63. Then, the upper end portion of the shaft portion is crimped to form the engaging portion. As a result, the negative electrode current collector terminal 7 is formed, and the negative electrode external electrode 5, the lid 2A, the negative electrode current collector terminal 7, and the electrode body 3 are integrally assembled.

  The second assembling step includes a step of inserting the electrode body 3 and the like into the case body 2B, disposing the lid 2A at the opening edge of the case body 2B, and a welding step. In the welding process, the outer peripheral edge of the lid 2A and the opening edge of the case body 2B are welded.

  In the injection step S8, the electrolytic solution 10 is supplied into the housing case 2 through the through hole 80a. Then, in the sealing step S9, the sealing member 80 is formed to close the through hole 80a.

As a result, the power storage device 1 shown in FIG. 1 is formed.
Next, the superiority of the power storage device 1 will be described by comparing the power storage device 1A according to the comparative example with the power storage device 1 according to the present embodiment.

  FIG. 32 is an exploded perspective view showing power storage device 1A. Power storage device 1A has substantially the same configuration as power storage device 1 except for the positive electrode current collector terminal and the negative electrode current collector terminal, and power storage device 1A has positive electrode current collector terminal 6B and negative electrode current collector terminal 7B. Including and

  FIG. 33 is a perspective view showing the positive electrode current collector terminal 6B. Like the positive electrode current collector terminal 6, the positive electrode current collector terminal 6B includes a plate portion 40 and a connecting shaft 41. The plate portion 40 is formed with a plurality of slits 45a to 45d. The positive electrode current collector terminal 6B includes a plate body 44 and a plurality of legs 46a to 46e. Then, welded portions 8a to 8e are also formed on the positive electrode current collector terminal 6B.

  On the other hand, the positive electrode collector terminal 6B is not formed with the grooves 50a to 50e and 53a to 53e.

  And a plurality of tabs 18 are inserted in each slit 45a-45d. The protrusions 26 and 27 are formed so as to protrude upward from both sides of each of 8a to 8e.

  FIG. 34 is a cross-sectional view showing the configuration of the positive electrode current collector terminal 6B and its surroundings. As shown in FIG. 34, the welded portion 8 is formed on the joint portion 28 of the tab 33, while the protruding portion 26 and the protruding portion 27 protrude upward from the upper surface of the positive electrode current collector terminal 6B.

  In order to prevent the upper ends of the protrusions 26 and 27 from coming into contact with the lid 2A, the lid 2A and the upper ends of the protrusions 26 and 27 are separated by a predetermined distance. As a result, a large space is formed between the upper surface of the positive electrode current collector terminal 6B and the lid 2A.

  Here, comparing FIG. 10 with FIG. 34, it can be seen that the power storage device 1 has a smaller dead space than the power storage device 1B.

  Similarly, also on the negative electrode side, the distance between the lid 2A of the power storage device 1 and the negative electrode current collecting terminal 7 may be shorter than the distance between the lid 2A of the power storage device 1B and the negative electrode current collecting terminal 7B. it can.

  As a result, power storage device 1 according to the present embodiment can be downsized as compared to power storage device 1B according to the comparative example.

  FIG. 35 is a cross-sectional view showing a power storage device 1C which is a modification of power storage device 1. In this power storage device 1C, the tab 18 is formed on the end side surface 24 of the electrode body 3, and the tab 33 is formed on the end side surface 25 of the electrode body 3. The positive electrode collector terminal 6 is arranged on the end side face 24 side, and the negative electrode collector terminal 7 is arranged on the end side face 25 side.

  FIG. 36 is a plan view showing a modified example of the positive electrode current collector terminal 6. In the example shown in FIG. 36, the groove portions 50a, 50b1, 50b2, 50c1, 50c2, 50d1, 50d2, 50e and the groove portions 51a, 51b1, 51b2, 51c1, 51c2, 51d1, 51d2, 51e have slits 45a to 45d. It is formed in the adjacent position. As described above, the groove portions formed in the legs 46a to 46e do not need to reach both sides in the width direction of the legs 46a to 46e.

  In the above embodiment, an example in which the configuration of the present disclosure is applied to the secondary battery has been described, but the present invention can also be applied to a power storage device such as a capacitor.

  Although the respective embodiments based on the present invention have been described above, the matters disclosed this time are examples in all respects and are not restrictive. The technical scope of the present invention is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

  1, 1A, 1B power storage device, 2 housing case, 2A lid, 2B case body, 3 electrode body, 4 positive electrode external electrode, 5 negative electrode external electrode, 6,6A, 6B, 7,7A, 7B, 62,65 terminals, 8, 8a, 8c, 8d, 8e, 9 Welds, 10 Electrolyte, 11 Positive electrode sheet, 12 Separator, 13 Negative electrode sheet, 15, 30, 61, 64 Metal plate, 16 Positive electrode mixture layer, 17, 32 Metal plate Main body, 18, 33 tabs, 20, 35 upper surface, 21 lower surface, 22, 23 main side surface, 24, 25 end side surface, 26, 27 protruding portion, 28 joint portion, 31 negative electrode mixture layer, 34 facing surface, 40 plate portion , 41 connecting shaft, 42 shaft, 43 engaging part, 44 plate body, 45a, 45d, 45e slit, 46a, 46b, 46c, 46d, 46e leg, 47, 48, 50a, 50b, 50c, 50d , 50e, 51, 51a, 51b, 51c, 51d, 51e, 53a, 53e Groove portion, 52a, 52b, 52c, 52d, 52e, 53a, 53b, 53c, 53d, 53e, 72, 74 Pedestal, 60, 63, 70 , 71 Insulating member, 61a, 64a, 80a Through hole, 73, 75 Cylindrical part, 80 Sealing member, 81, 82 Bundle part, 2013 JP, DP1, DP2 length, H direction, L1, L2 length, L3 , L4, L5 width, P1, P2 external force, S1 electrode body forming step, S2 preparing step, S3 inserting step, S4 clamping step, S5 welding step, S6 bending step, S7 assembling step, S8 injecting step, S9 sealing Step, S10 casting step, S11 pressing step, S12 slit forming step, SD stacking direction, TH thickness, W width direction.

Claims (1)

A power storage unit including a plurality of stacked metal plates;
A collector terminal welded to the power storage unit,
A welded portion for welding the collector terminal and the power storage unit;
Equipped with
Each metal plate of the plurality of metal plates includes a metal plate body and a tab formed so as to project from an outer peripheral edge portion of the metal plate,
The current collector terminal includes a facing surface located on the power storage body side and an opposite surface located on the opposite side to the facing surface,
The current collector terminal is formed so as to reach the opposite surface from the opposite surface and extend in one direction, and a slit into which the tab is inserted is formed,
A groove is formed on the opposite surface,
When the opposite surface is viewed in a plan view, the slit is formed so as to pass through the groove portion,
The tab includes a joining portion joined to the current collecting terminal by the welding portion, and a remaining portion adjacent to the joining portion,
The power storage device, wherein the remaining portion is housed in the groove.

Images