JP2019046613A - Power storage device - Google Patents

Abstract

To suppress generation of a high-temperature portion even in a case a heavy current flows for quick charge or the like in a power storage device comprising a CID.SOLUTION: A power storage device 1 includes an electrode body including an electrode, an accommodation case in which the electrode body is accommodated and an external terminal which is provided in the accommodation case, and comprises a collector terminal 6 which is connected to the electrode, and a cutout device 8 which is provided between the collector terminal 6 and the external terminal. The cutout device 8 includes a reverse plate 45, a rivet 46 which holds the reverse plate 45, and a bypass member 47. The reverse plate 45 includes a junction which is connected to a fragile part 49. The reverse plate 45 is formed so as to be reversely deformed away from the collector terminal 6. The rivet 46 includes a holding part which holds the reverse plate 45, and a hollow engage part 54 which is connected to the holding part and engaged with the external terminal. The bypass member 47 is inserted into the engage part 54 and electrically connected to the reverse plate 45 and the external terminal, and the bypass member 47 is moved away from the collector terminal 6 with the reverse deformation of the reverse plate 45.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a power storage device.

  Conventionally, a power storage device including an electrode body and a housing case for housing the electrode body is known. In such a power storage device, during overcharge or the like, the electrolytic solution is decomposed to generate gas, and the internal pressure in the housing case increases.

  In recent years, various types of power storage devices including a CID (Current Interrupt Device) have been proposed in order to suppress an excessive increase in internal pressure in the housing case (see Patent Documents 1 and 2).

  For example, a power storage device described in JP-A-2015-141879 includes an electrode body, a housing case, a negative external terminal, a positive external terminal, and a current interrupt mechanism.

  The current interruption mechanism includes a diaphragm and a rivet. The diaphragm is welded to the current collecting tab of the current collecting terminal. The rivet includes a holding portion that holds the outer peripheral side of the reversing plate, and a cylindrical portion that is formed so as to protrude upward from the holding portion. The cylinder portion of the rivet is engaged with the external terminal.

JP 2008-066254 A JP 2013-161712 A JP, 2015-141879, A

  In the above conventional power storage device, the current collecting terminal and the external terminal are electrically connected through an inversion plate and a rivet. On the other hand, the contact area between the reversing plate and the current collecting tab is small, and the contact area between the rivet and the reversing plate is also small. For this reason, when many electric currents flow like the time of quick charge, the temperature of each said contact part will become high.

  The present disclosure has been made in view of the above-described problems, and the object of the present disclosure is a portion that becomes high temperature even when a large amount of current flows, such as rapid charging, in a power storage device including a CID. It is providing the electrical storage apparatus which can suppress that generation | occurrence | production occurs.

  The power storage device includes an electrode body having an electrode, a housing case for housing the electrode body, an external terminal provided in the housing case, a current collecting terminal connected to the electrode, and between the current collecting terminal and the external terminal. And a provided shut-off device. The said interruption | blocking apparatus contains the rivet arrange | positioned at intervals from the current collection terminal, the inversion board hold | maintained by the rivet, and a bypass member. The rivet includes a holding portion that holds the reversing plate, and a hollow engaging portion that is connected to the holding portion and engages with an external terminal. A part of the reversing plate is joined to a current collecting terminal. The reversing plate is deformed so as to be separated from the current collecting terminal when the joined state with the current collecting terminal is released by the internal pressure in the housing case. The bypass member is inserted into the engaging portion and disposed on the upper surface of the reversing plate, and is electrically connected to the reversing plate and the external terminal. The bypass member moves away from the current collecting terminal as the reversing plate is deformed.

  According to the above power storage device, the external terminal and the current collecting terminal are electrically connected by the bypass member in a state before the reversing plate is reversely deformed. As a result, the electrical resistance between the external terminal and the current collecting terminal is kept low. Therefore, even if a large amount of current flows between the external terminal and the current collecting terminal, a portion that generates heat is hardly generated between the external terminal and the current collecting terminal.

  On the other hand, when the internal pressure in the housing case becomes higher than the CID operating pressure, the load for pushing up the reverse plate increases, and the reverse plate is reversely deformed so as to be separated from the current collecting terminal. As the reversal plate is deformed, the bypass member also moves away from the current collecting terminal. As a result, the electrical connection between the current collecting terminal and the external terminal is disconnected.

  According to the power storage device according to the present disclosure, even when a large amount of current flows, such as rapid charging, in the power storage device including the CID, it is possible to suppress the occurrence of a high temperature portion.

It is a section perspective view showing power storage device 1 according to the present embodiment. 2 is an exploded perspective view showing an electrode body 2. FIG. It is a cross-sectional perspective view which shows the structure of the positive electrode external terminal 4 and its periphery. FIG. 3 is a cross-sectional perspective view showing a blocking device 8. 2 is a cross-sectional perspective view showing a negative electrode external terminal 5. FIG. It is a cross-sectional perspective view which shows the state which the cutoff device 8 act | operated. 3 is a process flow diagram illustrating a manufacturing process of the power storage device 1. FIG. It is a cross-sectional perspective view which shows rivet insertion process S1. It is a section perspective view showing caulking process S2. It is a cross-sectional perspective view which shows welding process S3. It is a cross-sectional perspective view which shows welding process S4. It is a cross-sectional perspective view which shows insertion process S5. This is a step showing the caulking step S6. It is a cross-sectional perspective view which shows a part of 1 A of electrical storage apparatuses which concern on the modification of an electrical storage apparatus. FIG. 6 is a cross-sectional perspective view showing a state where the reversal plate 45 is reversed and deformed in the power storage device 1A. It is a cross-sectional perspective view which shows the electrical storage apparatus 1B which concerns on the 2nd modification of an electrical storage apparatus. In the electrical storage device 1B, it is a cross-sectional perspective view showing a state in which the reverse plate 45 is reversely deformed. It is a cross-sectional perspective view which shows a part of 1 C of electrical storage apparatuses which concern on a comparative example.

  A power storage device according to the present embodiment will be described with reference to FIGS. Among the configurations shown in FIGS. 1 to 18, the same or substantially the same configuration may be denoted by the same reference numeral and redundant description may be omitted.

  FIG. 1 is a cross-sectional perspective view showing a power storage device 1 according to the present embodiment. The power storage device 1 includes an electrode body 2, a housing case 3, a positive electrode external terminal 4, a negative electrode external terminal 5, a positive electrode current collector terminal 6, a negative electrode current collector terminal 7, a blocking device 8, and an electrolyte solution 9. Prepare.

  The electrode body 2, the positive electrode current collector terminal 6, the negative electrode current collector terminal 7, the blocking device 8, and the electrolyte solution 9 are accommodated in the accommodation case 3.

  The electrode body 2 includes a plurality of positive electrode sheets 10, a plurality of separators 11, and a plurality of negative electrode sheets 12. The electrode body 2 is formed in a substantially rectangular parallelepiped shape. The electrode body 2 includes a positive electrode 15 formed on one end side and a negative electrode 16 formed on the other end side.

  FIG. 2 is an exploded perspective view showing the electrode body 2. The electrode body 2 is formed by sequentially laminating a positive electrode sheet 10, a separator 11, and a negative electrode sheet 12.

  The positive electrode sheet 10 includes a metal foil 20 and a positive electrode mixture layer 21. The metal foil 20 is made of aluminum or an aluminum alloy. The positive electrode mixture layer 21 is formed on the front and back surfaces of the metal foil 20. The positive electrode mixture layer 21 includes a positive electrode active material and a binder. The metal foil 20 is formed in a rectangular shape, and an uncoated portion 22 in which the positive electrode mixture layer 21 is not formed is formed on the metal foil 20.

  The negative electrode sheet 12 includes a metal foil 25 and a negative electrode mixture layer 26. The metal foil 25 is made of copper or a copper alloy. The negative electrode mixture layer 26 is formed on the front and back surfaces of the metal foil 25. The negative electrode mixture layer 26 includes a negative electrode active material and a binder. In the metal foil 25, an uncoated portion 27 in which the negative electrode mixture layer 26 is not formed is formed.

  In FIG. 1, the positive electrode 15 is formed by laminating a plurality of uncoated portions 22. The negative electrode 16 is formed by laminating a plurality of uncoated portions 27.

  The housing case 3 includes a case body 30 and a lid 31. The case body 30 and the lid 31 are made of, for example, aluminum or an aluminum alloy. The case main body 30 has an opening that opens upward.

  The lid 31 is disposed at the opening of the case body 30, and the outer peripheral edge of the lid 31 is welded to the opening edge of the case body 30. A liquid injection port 32 a is formed in the lid 31, and the liquid injection port 32 a is sealed with a sealing member 32. The electrolytic solution 9 is stored on the bottom surface side of the storage case 3.

  The positive external terminal 4 and the negative external terminal 5 are disposed on the upper surface of the lid 31. FIG. 3 is a cross-sectional perspective view showing the configuration of the positive external terminal 4 and its surroundings. The positive external terminal 4 includes an insulator 35, a terminal plate 36, and a terminal bolt 37.

  The insulator 35 is provided on the upper surface of the lid 31. The terminal board 36 is provided on the upper surface of the insulator 35. The terminal plate 36 is a metal plate. The terminal bolt 37 is disposed on the upper surface side of the insulator 35 and on the lower surface side of the terminal plate 36. The terminal bolt 37 is formed so as to protrude from the upper surface of the terminal plate 36 through a through hole formed in the terminal plate 36.

  The positive electrode current collector terminal 6 includes a current collector plate 40 and a pedestal 41. The current collector plate 40 is welded to the positive electrode 15 of the electrode body 2. The current collector plate 40 is formed to extend in the vertical direction. The pedestal 41 is provided at the upper end portion of the current collector plate 40. The pedestal 41 is formed in a plate shape. The base 41 is disposed below the positive external terminal 4 and the lid 31. The blocking device 8 is disposed between the pedestal 41 and the lid 31, and an insulating member 42 is disposed between the blocking device 8 and the lid 31.

  FIG. 4 is a cross-sectional perspective view showing the blocking device 8. The insulating member 42 includes a pedestal 43 and a cylindrical portion 44. The pedestal 43 is formed in a plate shape. The cylindrical portion 44 is formed so as to protrude upward from the upper surface of the pedestal 43. The cylinder part 44 is formed in a hollow shape, and a through hole 44a is formed.

  Note that a through hole 36 a is formed in the terminal plate 36, and a through hole 35 a is also formed in the insulator 35. A through hole 31 a is formed in the lid 31. The cylindrical portion 44 of the insulating member 42 is inserted into the through hole 31a.

  The insulating member 42, the insulator 35, and the terminal plate 36 are disposed so that the through hole 44a, the through hole 35a, and the through hole 36a communicate with each other.

  A fragile portion 49 is formed on the pedestal 41 of the positive electrode current collecting terminal 6. The thickness of the fragile portion 49 is thinner than the thickness of the portion of the pedestal 41 located around the fragile portion 49. For this reason, the strength of the fragile portion 49 is lower than the strength of the portion of the base 41 located around the fragile portion 49. A through hole 49 a is formed in the fragile portion 49.

  The shut-off device 8 includes a reversing plate 45, a rivet 46, a bypass member 47, and a fixing plate 48. The reversing plate 45 is formed in a plate shape, and the central portion of the reversing plate 45 is welded to the upper surface of the fragile portion 49. Specifically, the reversing plate 45 is welded to the opening edge portion of the through hole 49a, and the reversing plate 45 closes the through hole 49a. The outer peripheral edge of the reversing plate 45 is welded to the rivet 46.

  The rivet 46 includes a pedestal 50, an engagement portion 54, and a fixing plate 48. The rivet 46 is made of a conductive metal material. The engaging portion 54 is formed in a hollow shape, and the engaging portion 54 includes a cylindrical portion 51 and an overhang portion 52. The tube portion 51 is formed in a hollow shape, and the overhang portion 52 is formed at the upper end portion of the tube portion 51. The cylinder part 51 is arrange | positioned so that it may pass through the through-hole 44a, the through-hole 35a, and the through-hole 36a. The overhang portion 52 is formed in an annular shape, and the overhang portion 52 is engaged with the terminal board 36. For this reason, the engaging part 54 is engaged with the terminal plate 36 (positive electrode external terminal 4). An outer peripheral edge portion of the overhang portion 52 is welded to the terminal plate 36. Thereby, the terminal board 36, the insulator 35, the lid | cover 31, the insulating member 42, and the rivet 46 are being fixed integrally.

  The pedestal 50 is formed in a substantially plate shape. A recess 53 is formed on the lower surface of the pedestal 50. The through hole 51 a of the cylindrical portion 51 communicates with the recess 53, and the outer peripheral edge of the reversing plate 45 is welded to the inner peripheral surface of the recess 53. The inside of the housing case 3 and the outside of the housing case 3 are partitioned by the reversing plate 45. The upper surface side of the reversing plate 45 is the atmospheric pressure, and the lower surface side of the reversing plate 45 is the internal pressure in the housing case 3. The rivet 46 is disposed at a distance from the pedestal 41.

  The bypass member 47 is formed so as to extend in the vertical direction, and is formed of a conductive metal member. A lower end portion of the bypass member 47 is disposed on the reversing plate 45. Specifically, the bypass member 47 is disposed in a portion of the reversing plate 45 located on the fragile portion 49. The bypass member 47 is inserted into the through hole 51 a of the cylindrical portion 51. The upper end portion of the bypass member 47 is located above the upper surface of the terminal board 36.

  The fixing plate 48 is provided so as to cover the upper end of the bypass member 47 and the upper surface of the overhang portion 52. The fixing plate 48 is made of a conductive metal material. The fixing plate 48 is welded to the bypass member 47 and the overhanging portion 52. For this reason, the bypass member 47 is electrically connected to the base 41 and the terminal plate 36.

  In the state shown in FIG. 4, the current flowing between the positive electrode 15 of the electrode body 2 and the positive external terminal 4 mainly includes the positive current collector terminal 6, the reverse plate 45, the bypass member 47, and the fixed plate. 48 and the overhanging portion 52 pass through. The contact area between the bypass member 47 and the reversing plate 45 is large, and the contact area between the bypass member 47 and the fixed plate 48 is large. Therefore, a large amount of current passes through the bypass member 47 and the amount of current passing through the welded portion between the outer peripheral edge of the reversing plate 45 and the base 50 is small. The contact area between the outer peripheral edge of the reversing plate 45 and the pedestal 50 is small, and the electrical resistance of the portion is high. If a large amount of current flows between the outer peripheral edge of the reversing plate 45 and the pedestal 50, the portion may become hot. On the other hand, in power storage device 1 according to the present embodiment, the amount of current passing through the outer peripheral edge of reversing plate 45 and pedestal 50 can be reduced, so that there is a large amount between electrode body 2 and positive electrode external terminal 4. The amount of heat generated when this current flows can be reduced.

  FIG. 5 is a cross-sectional perspective view showing the negative electrode external terminal 5. The negative external terminal 5 includes an insulator 60, a terminal plate 61, and a terminal bolt 62. The insulator 60 is provided on the upper surface of the lid 31. The terminal board 61 is provided on the upper surface of the insulator 60. The terminal board 61 is made of a conductive metal material. The terminal bolt 62 is provided on the upper surface of the insulator 60, and is formed in the terminal plate 61 so as to protrude upward from the upper surface of the terminal plate 61 through a through hole.

  The negative electrode current collector terminal 7 includes a connection member 65, a pedestal 66, and a current collector plate 67. The pedestal 66 is formed in a plate shape and is disposed below the lid 31. An insulating member 64 is disposed between the pedestal 66 and the lid 31.

  The connection member 65 is formed so as to protrude upward from the upper surface of the base 66. An overhang portion 68 is formed at the upper end portion of the connection member 65, and the connection member 65 is engaged with the terminal board 61. The overhanging portion 68 is welded to the terminal plate 61. The current collector plate 67 is welded to the negative electrode 16 of the electrode body 2. For this reason, the negative electrode 16 and the negative external terminal 5 are electrically connected by the negative current collecting terminal 7.

  In the power storage device 1 configured as described above, an overcharge or an internal short circuit may occur. When overcharging or an internal short circuit occurs, a large amount of current flows in the electrode body 2, and the electrolytic solution 9 is decomposed in the vicinity of the positive electrode current collector terminal 6 to generate gas. As a result, the internal pressure in the storage case 3 increases.

  When the internal pressure in the housing case 3 rises, the reversing plate 45 is pushed upward by the pressure difference between the pressure on the lower surface side of the reversing plate 45 and the pressure on the upper surface side of the reversing plate 45. FIG. 6 is a cross-sectional perspective view showing a state where the blocking device 8 is activated. When the internal pressure in the housing case 3 becomes the CID operating pressure, the fragile portion 49 is broken by the load applied to the fragile portion 49 from the reversing plate 45. When the fragile portion 49 is broken, the reverse plate 45 is reversely deformed as shown in FIG. Specifically, the reversing plate 45 is deformed so that the central portion protrudes upward.

  As described above, when the reversing plate 45 is deformed, the reversing plate 45 and the pedestal 41 are separated, and the electrical connection between the reversing plate 45 and the pedestal 41 is cut. Thereby, the electrical connection between the positive external terminal 4 and the positive electrode 15 is disconnected.

  Thereby, it can suppress that an electric current flows into the electrode body 2, can suppress the decomposition reaction of the electrolyte solution 9, and can stop the internal pressure rise in the storage case 3. FIG.

  The reversing plate 45 is deformed upward by the internal pressure in the housing case 3, and the fixed plate 48 is separated from the overhanging portion 52 by a load applied to the reversing plate 45. Specifically, the welded portion that welds the fixing plate 48 and the overhanging portion 52 is broken.

  Thereby, the bypass member 47 and the fixed plate 48 move upward along with the reverse deformation of the reverse plate 45.

  Thus, according to the power storage device 1 according to the present embodiment, in a normal state, the electrical resistance is kept low between the electrode body 2 and the positive electrode external terminal 4, and further, the housing case When the internal pressure in 3 increases, the electrical connection between the electrode body 2 and the positive external terminal 4 can be disconnected.

  A method for manufacturing the power storage device 1 configured as described above will be described. FIG. 7 is a process flowchart showing the manufacturing process of the power storage device 1. As shown in FIG. 7, the manufacturing process of the power storage device 1 includes the rivet insertion process S1, the caulking process S2, the welding process S3, the welding process S4, the insertion process S5, the caulking process S6, and the welding process S7. And an insertion step S8, a liquid injection step S9, and a sealing step S10.

  FIG. 8 is a cross-sectional perspective view showing the rivet insertion step S1. The rivet inserting step S1 includes a member arranging step and a rivet 46A inserting step.

  The member arranging step includes a step of arranging the positive external terminal 4 on the upper surface of the lid 31 and a step of arranging the insulating member 42 on the lower surface side of the lid 31.

  The rivet 46A includes a cylindrical portion 51A and a pedestal 50. The overhanging portion is not formed at the upper end portion of the cylindrical portion 51A.

  In the insertion process of the rivet 46A, the cylindrical portion 51A is inserted into each through hole formed in the insulating member 42, the lid 31 and the terminal plate 36. Thereby, the upper end portion of the cylinder portion 51 </ b> A protrudes from the upper surface of the terminal plate 36.

  FIG. 9 is a cross-sectional perspective view showing the caulking step S2. In the caulking step S2, the upper end portion of the cylindrical portion 51A is deformed to form the overhang portion 52. Then, the outer peripheral edge portion of the overhang portion 52 is welded to the upper surface of the terminal plate 36 by a laser L or the like.

  FIG. 10 is a cross-sectional perspective view showing the welding step S3. The welding step S <b> 3 includes a step of disposing the reversing plate 45 in the recess 53 of the rivet 46 and a step of welding the outer peripheral edge of the reversing plate 45 to the rivet 46. The outer peripheral edge of the reversing plate 45 is welded with, for example, a laser L.

  FIG. 11 is a cross-sectional perspective view showing the welding step S4. The welding step S4 includes a step of attaching the positive electrode current collecting terminal 6 and a step of welding the reversing plate 45.

  The step of attaching the positive electrode current collecting terminal 6 is a step of welding the base 41 to the bases 70 and 71 provided on the lower surface of the lid 31. The welding process of the reversing plate 45 is a process of welding the central portion of the reversing plate 45 to the fragile portion 49 of the base 41 using a laser L or the like.

  FIG. 12 is a cross-sectional perspective view showing the insertion step S5. The insertion step S <b> 5 is a step of inserting the connecting member 65 of the negative electrode current collecting terminal 7 into each through hole of the insulating member 64, the lid 31, the insulator 60 and the terminal plate 61. In addition, in this insertion process S5, the overhang | projection part 68 is not formed in the upper end part of the connection member 65. FIG.

  FIG. 13 is a step showing the caulking step S6. In the caulking step S6, the upper end portion of the connecting member 65 is caulked to form the overhanging portion 68. The outer peripheral edge portion of the overhang portion 68 is welded to the terminal plate 61.

  In the welding step S <b> 7, the positive electrode current collector terminal 6 and the negative electrode current collector terminal 7 are welded to the electrode body 2. As a result, the electrode body 2, the positive electrode current collector terminal 6, the negative electrode current collector terminal 7, the lid 31, the positive electrode external terminal 4, and the negative electrode external terminal 5 are integrated.

  In the insertion step S <b> 8, the electrode body 2 is inserted into the case body 30, and then the lid 31 is welded to the opening edge of the case body 30.

  In the injection step S9, the electrolyte 9 is injected into the housing case 3 from the injection port 32a, and the injection port 32a is closed with the sealing member 32 in the sealing step S10. Thereby, the electrical storage apparatus 1 can be manufactured.

  FIG. 14 is a cross-sectional perspective view showing a part of a power storage device 1A according to a modification of the power storage device. The configuration of power storage device 1A is the same as that of power storage device 1 except for the configuration of fixing plate 48A.

  A fragile portion 75 is formed on the fixing plate 48A. The fragile portion 75 extends along the upper end surface of the bypass member 47 and is formed in an annular shape.

  The thickness of the portion of the fixed plate 48A where the fragile portion 75 is located is thinner than the thickness of the portion of the fixed plate 48A located around the fragile portion 75. For this reason, the strength of the fragile portion 75 is lower than the strength of the portion located around the fragile portion 75.

  FIG. 15 is a cross-sectional perspective view showing a state where the reversal plate 45 is reversed and deformed in the power storage device 1A. When the internal pressure in the housing case 3 rises, the reversing plate 45 receives the internal pressure in the housing case 3 and the reversing plate 45 tends to deform.

  At this time, part of the load received by the reversing plate 45 is transmitted to the bypass member 47. The load transmitted to the bypass member 47 is applied to the fixed plate 48A. When the load applied to the fixing plate 48A exceeds a predetermined value, the fragile portion 75 is broken. When the fragile portion 75 is broken, the bypass member 47 can move upward and the reversing plate 45 can be reversibly deformed.

  Thus, the fixed plate 48A prevents the reverse deformation of the reverse plate 45, and when the internal pressure in the housing case 3 becomes equal to or higher than the CID operating pressure, the reverse plate 45 is reversely deformed. Thereby, the electrical connection between the positive electrode external terminal 4 and the electrode body 2 can be cut off.

  FIG. 16 is a cross-sectional perspective view showing a power storage device 1B according to a second modification of the power storage device. The power storage device 1B is substantially the same as the power storage device 1 except for the configurations of the bypass member 47B and the fixing plate 48B.

  The bypass member 47B provided in the power storage device 1B is formed to be tapered toward the upper end side. In other words, the area of the upper end portion of the bypass member 47B is smaller than the area of the lower end portion of the bypass member 47B.

  A marking portion 76 is formed on the fixed plate 48B. The marking part 76 is formed in the position which opposes the upper end surface of the bypass member 47B among the fixed plates 48B. The marking part 76 is formed in a cross-shaped groove shape. The strength of the portion of the fixed plate 48B where the stamped portion 76 is located is lower than the strength of the portion of the fixed plate 48B located around the stamped portion 76.

  FIG. 17 is a cross-sectional perspective view showing a state where the reversal plate 45 is reversed and deformed in the power storage device 1B. A load due to the internal pressure in the housing case 3 is applied to the lower surface of the reversing plate 45. A part of the load applied to the storage case 3 is applied to the lower end surface of the bypass member 47B.

  The load applied to the lower end surface of the bypass member 47B is transmitted from the upper end surface of the bypass member 47B to the fixed plate 48B.

  Here, the area of the upper end surface of the bypass member 47B is smaller than the area of the lower end surface of the bypass member 47B. For this reason, the stress that the upper end portion of the bypass member 47B presses the fixing plate 48B per unit area is larger than the stress applied to the lower end surface of the bypass member 47B. As a result, the stress applied to the stamped portion 76 of the fixed plate 48B increases, and the stamped portion 76 is easily broken.

  When the marking portion 76 is broken, the bypass member 47B can move upward, and the reversing plate 45 is reversed and deformed.

  As described above, according to the power storage device 1B, when the internal pressure in the housing case 3 becomes the CID operating pressure, it is possible to suppress the deformation of the reversing plate 45 by the fixing plate 48B.

  Next, a case where the power storage device 1C according to the comparative example is compared with the power storage devices 1, 1A, 1B will be described.

  FIG. 18 is a cross-sectional perspective view showing a part of a power storage device 1C according to a comparative example. Unlike the power storage devices 1, 1 </ b> A, 1 </ b> B, the power storage device 1 </ b> C does not include the fixed plate 48 and the bypass member 47. On the other hand, in the configuration other than the fixed plate 48 and the bypass member 47, the power storage device 1 </ b> C has the same configuration as the power storage device 1.

  Referring to FIG. 3, terminal plate 36 of each power storage device 1, 1A, 1B, 1C is made of aluminum, specifically, A1050. The length in the width direction W of the terminal board 36 is 35 mm, and the length in the depth direction TH is 16 mm. The length in the height direction H is 1.5 mm.

  Referring to FIG. 4, the hole diameter of through hole 51a of rivet 46 of each power storage device 1, 1A, 1B, 1C is 2.4 mm. The outer diameter of the cylindrical part 51 is 4 mm, and the outer diameter of the pedestal 50 is 18 mm. The length in the height direction H from the lower surface of the pedestal 50 to the upper surface of the overhang portion 52 is 6.6 mm. The rivet 46 is made of aluminum, specifically, A1050.

  The reverse plate 45 has an outer diameter of 16.6 mm, and the reverse plate 45 has a length (thickness) in the height direction H of 0.3 mm. The reverse plate 45 is made of aluminum, specifically, A1050. The plate thickness of the positive electrode current collector terminal 6 is, for example, 0.8 mm. The thickness of the fragile portion 49 is 0.2 mm.

  Next, the configuration of the power storage device 1 will be described. In the power storage device 1, the outer diameter of the bypass member 47 is 2 mm, and the length in the height direction H of the bypass member 47 is 7 mm. The bypass member 47 is formed in a cylindrical shape. The bypass member 47 is made of aluminum, specifically, A1050. The outer diameter of the fixing plate 48 is 6 mm, and the thickness of the fixing plate 48 is 0.3 mm. The overhang portion 52 and the fixing plate 48 are through-welded at three locations. The diameter of through welding is 1 mm.

  Next, the configuration of the power storage device 1A will be described. Referring to FIG. 14, in power storage device 1A, the outer diameter of bypass member 47 is 2 mm. The height in the height direction H of the bypass member 47 is 7 mm. The bypass member 47 is made of aluminum, specifically, A1050.

  The outer diameter of the fixing plate 48 is 6 mm, and the thickness of the fixing plate 48 is 0.3 mm. The thickness of the fragile portion 75 is 0.05 mm. The fixed plate 48 and the overhanging portion 52 are through welded over the entire circumference.

  Next, the power storage device 1B will be described. Referring to FIG. 16, the outer diameter of the lower end portion of bypass member 47B is 2.4 mm, and the diameter of the upper end portion of bypass member 47B is 1.6 mm. The height in the height direction H of the bypass member 47B is 7 mm. The bypass member 47B has a truncated cone shape. The bypass member 47B is made of aluminum, specifically, A1050.

  The outer diameter of the fixing plate 48B is 6 mm, and the thickness of the fixing plate 48B is 0.3 mm. The thickness of the stamped portion 76 is 0.05 mm, and the groove width of the stamped portion 76 is 4 mm. The fixed plate 48B and the overhanging portion 52 are welded through the entire circumference.

  The manufacturing process of each power storage device 1, 1A, 1B, 1C is the manufacturing process shown in FIG. The power storage devices 1, 1A, 1B configured as described above and the power storage device 1C of the comparative example were each evaluated by the following methods.

  In each power storage device 1, 1 </ b> A, 1 </ b> B, 1 </ b> C, a current 200 </ b> A is applied to the upper surface of the terminal bolt 37. And the electric current was sent in the state of the voltage 0V by making the base 41 of the positive electrode current collection terminal 6 into earth | ground. Under these conditions, CAE (Computer Aided Engineering) analysis is performed.

  Starting from an atmosphere of 25 ° C., the temperature of the insulator 35 after 1000 seconds is measured. Table 1 below shows the evaluation results.

  As apparent from Table 1 above, in the power storage devices 1, 1 </ b> A, 1 </ b> B, it can be seen that the temperature of the insulator 35 is less than 100 degrees. That is, it can be seen that the power storage devices 1, 1 </ b> A, 1 </ b> B can suppress the thermal degradation of the insulator 35. The above results were obtained because in the power storage devices 1, 1 </ b> A, 1 </ b> B, a portion having a high electrical resistance occurs between the positive external terminal 4 and the positive current collector terminal 6. It can be inferred that this is because of the suppression. On the other hand, in the power storage device 1 </ b> C, it can be inferred that the electrical resistance is high at the joint between the reversing plate 45 and the rivet 46 and that the part generates heat. As a result, in the power storage device 1C, it can be inferred that the temperature of the insulator 35 has increased.

  As mentioned above, although each embodiment and Example based on this invention were demonstrated, the matter disclosed this time is an illustration and restrictive at no points. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 1A, 1B, 1C Power storage device, 2 electrode body, 3 housing case, 4 positive external terminal, 5 negative external terminal, 6, 7 terminal, 8 interruption device, 9 electrolyte, 10 positive electrode sheet, 11 separator, 12 negative electrode Sheet, 15 Positive electrode, 16 Negative electrode, 20, 25 Metal foil, 21 Positive electrode mixture layer, 22, 27 Uncoated part, 26 Negative electrode mixture layer, 30 Case body, 31 Lid, 31a, 35a, 36a, 44a, 51a through hole, 32 sealing member, 32a liquid port, 35, 60 insulator, 36, 61 terminal plate, 37, 62 terminal bolt, 40, 67 plate, 41, 43, 50, 66 base, 42, 64 insulating member, 44, 51, 51A cylinder part, 45 reversing plate, 46, 46A rivet, 47, 47B bypass member, 48, 48A, 48B fixing plate, 49, 75 weak part, 2,68 overhang, 53 recess, 65 connection member, 70, 71 units, 76 engraved part, H height direction, L laser, S1 rivet insertion process, S2, S6 caulking process, S3, S4, S7 welding process, S5, S8 insertion process, S9 liquid injection process, S10 sealing process, W width direction.

Claims (1)

An electrode body having an electrode;
A housing case for housing the electrode body;
An external terminal provided in the housing case;
A current collecting terminal connected to the electrode;
A breaking device provided between the current collecting terminal and the external terminal;
With
The shut-off device includes a rivet disposed at a distance from the current collecting terminal, a reversing plate held by the rivet, and a bypass member,
The rivet includes a holding portion that holds the reversing plate, and a hollow engaging portion that is connected to the holding portion and engages with the external terminal,
A part of the reversing plate is joined to the current collecting terminal,
The reversing plate is deformed so that the joined state with the current collecting terminal is released by the internal pressure in the housing case and separated from the current collecting terminal,
The bypass member is inserted into the engagement portion and disposed on the upper surface of the reversing plate, and is electrically connected to the reversing plate and the external terminal,
The bypass member moves away from the current collecting terminal as the reversing plate is deformed.

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