JP2018049738A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of suppressing a part of an electrode from scattering from a pressure release valve having been cleaved in a nail penetration test, and also suppressing a part adjoining the pressure release valve from being fused at a wall part.SOLUTION: A shield member 60 of a secondary battery 10 comprises a shield part 61 supported on a tab-side end face 12b with a pressure release valve 18 covered from the side of an electrode assembly 12. The shield member 60 comprises a first abutting part 67 which is integrated with the shield part 61 and can abut on a negative electrode-side end face 51a of a negative electrode conductive member 51, and a second rib 63 which protrudes from the shield part 61 toward the lid body 14 and can abut on a positive electrode-side end face 41a of a positive electrode conductive member 41. Further, the shield member 60 comprises an opening part 61b which is present closer to the shield part 61 than to the first abutting part 67 in a juxtaposition direction in plan view where the lid body 14 is viewed from an outer surface 14b, and exposes a tab-side end face 12b in plan view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device including a pressure release valve.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. For example, as described in Patent Document 1, the secondary battery includes a case in which an electrode assembly and an electrolytic solution are housed, and a pressure relief valve that releases the pressure inside the case to the outside of the case on the wall portion of the case Is provided.

  In such a secondary battery, when a nail penetration test, which is one of the evaluation tests, is performed, the separator between the positive electrode and the negative electrode is broken by the nail, and the positive electrode and the negative electrode are short-circuited in the case. To do. When a short circuit occurs, heat is generated around the short circuit part, the electrolyte component is decomposed by the heat generated around the short circuit part, and gas is generated in the case. Then, the pressure in the case rises and the pressure release valve is opened, but when the gas is released from the pressure release valve to the outside of the case, a part of the electrode is scraped off by the high pressure gas, and it gets on the gas as it is. There is a risk of splashing outside.

  When a part of the electrode is released out of the case, it can spark. In order to prevent the sparks from being scattered, for example, as shown in FIG. 8, Patent Document 1 includes a safety protection device 92 disposed opposite to a pressure relief valve 91 (pressure release valve) provided on the battery upper lid 90. . The safety protection device 92 includes a baffle plate 93 that faces the pressure relief valve 91 and covers the pressure relief valve 91, and a pair of frame-shaped side walls 94 that are erected from the baffle plate 93. Further, the safety protection device 92 includes a first gas flow passage 95 formed in the frame of each side wall 94 and a second gas flow passage 96 that opens at a position sandwiched between the side walls 94.

  In the nail penetration test, even if a part of the electrode is scraped by the gas, a part of the electrode is rebounded by the baffle plate 93 together with the gas. Then, it is suppressed that a part of electrode is discharged | emitted out of a case with gas, and scattering of a spark is suppressed. The gas from which a part of the electrode has been removed is discharged from the pressure relief valve 91 to the outside of the case via the gas flow passages 95 and 96.

Japanese Patent Laid-Open No. 2006-96129

  However, when the generated gas has a strong momentum, even if the gas collides with the baffle plate 93 and flows toward the gas flow passages 95, 96, when the gas flows toward the pressure relief valve 91, There is a possibility that it will melt by colliding with a portion adjacent to the pressure relief valve 91.

  An object of the present invention is to provide a power storage device that can prevent a part of an electrode from scattering from a cleaved pressure release valve during a nail penetration test and can suppress melting of a portion adjacent to the pressure release valve in a wall portion. There is.

  A power storage device for solving the above problems includes an electrode assembly configured in layers with electrodes having different polarities insulated by a separator, an electrolytic solution, and a case for housing the electrode assembly and the electrolytic solution. A pressure release valve that is present in the wall of the case and is opened when the pressure in the case reaches an open pressure, and releases the pressure in the case to the outside of the case, and is connected to each electrode of each polarity And a pair of conductive members interposed between the inner surface of the wall portion and the end surface of the electrode assembly facing the inner surface, and arranged in parallel along the end surface of the electrode assembly. An apparatus comprising: a shielding member positioned between the pair of conductive members in the juxtaposition direction of the pair of conductive members and placed on an end face of the electrode assembly, wherein the shielding member includes the pressure Whether the release valve is on the electrode assembly side A shielding part supported on the end face of the electrode assembly in a covered state, a first abutting part integral with the shielding part and capable of abutting against one conductive member, and from the shielding part toward the wall part And a second contact portion that can contact the other conductive member, and in the plan view when the wall portion is viewed from the outer surface, the shield is more shielded than the first contact portion in the juxtaposed direction. And an opening that is present near the portion and exposes an end surface of the electrode assembly in the plan view.

  According to this, when the nail is inserted into the power storage device during the nail penetration test, electrodes having different polarities are short-circuited in the case via the nail. When a short circuit occurs, heat is generated around the short circuit part, and the electrolyte component is decomposed to generate gas. Due to the generation of gas, the pressure in the power storage device increases. When the internal pressure of the case reaches the open pressure of the pressure release valve, the pressure release valve is cleaved and the gas in the case is released out of the case.

  The gas generated in the short circuit part collides with the shielding part on the way to the cleaved pressure relief valve, and changes its direction along the outer surface of the shielding part. On the first contact portion side and the second contact portion side, since the first contact portion side where the opening exists is a wider flow path, a large amount of gas flows to the first contact portion side. And the gas which flowed into the opening part bends at the edge part of a shielding part, and goes to a pressure relief valve.

  Compared with the case where there is no opening, the position where the gas bends toward the pressure release valve (the edge of the shield) can be brought closer to the pressure release valve in the juxtaposition direction. Then, by adjusting the dimension of the shielding part in the juxtaposed direction and the opening width of the opening part, adjusting the position of the edge part of the shielding part, and adjusting the angle at which the gas is bent, the gas is turned into the pressure release valve. Can be flowed directly. As a result, it is possible to prevent the gas bent at the edge of the shielding portion from colliding with a portion adjacent to the pressure release valve in the wall, and to prevent the wall from being melted by the gas.

  Then, the movement of the shielding member in the juxtaposition direction is restricted by the contact between the first contact portion and the one conductive member, and the contact between the second contact portion and the other conductive member. For this reason, it can suppress that the position of an opening part and the position of the edge part of the shielding part where gas bends are moved by the collision of gas, and the state which gas flows directly into a pressure release valve can be maintained.

  In the power storage device, the shielding member includes a first rib erected from a pair of edges extending in the juxtaposition direction in the shielding part, and the extending in a direction orthogonal to the juxtaposition direction in the shielding part. A second rib standing from an edge near the other conductive member of the pair of edges of the shielding part, and the second rib is the second contact part.

  According to this, since the 2nd rib functions as the 2nd contact part, the 2nd rib has stood up to the position which can contact the other conductive member. Therefore, the gas flow toward the pressure release valve is narrowed by the second rib as compared with the first contact portion side, so that the gas becomes easier to flow to the opening.

  The power storage device is a secondary battery.

  According to the present invention, at the time of a nail penetration test, it is possible to prevent a part of the electrode from scattering from the cleaved pressure release valve, and it is possible to inhibit melting of a portion adjacent to the pressure release valve in the wall portion.

The disassembled perspective view which shows the secondary battery of embodiment. The perspective view which shows the external appearance of a secondary battery. The disassembled perspective view which shows the component of an electrode assembly. The top view which shows a secondary battery. The fragmentary sectional view which shows the inside of a secondary battery. The partially broken front view which shows the secondary battery at the time of a nail penetration test. The perspective view which shows the secondary battery provided with the shielding member of another example. The figure which shows background art.

Hereinafter, an embodiment in which the power storage device is embodied as a secondary battery will be described with reference to FIGS.
As shown in FIG. 1 or 2, the secondary battery 10 as the power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 12 accommodated in a case 11 and an electrolytic solution. The case 11 includes a case main body 13 having an opening 13 a and a lid body 14 that closes the opening 13 a of the case main body 13.

  Both the case body 13 and the lid body 14 are made of aluminum. The case main body 13 includes a rectangular plate-like bottom wall 13b, a short side wall 13c having a shape protruding from the short side edge of the bottom wall 13b, and a long side wall 13d having a shape protruding from the long side edge of the bottom wall 13b. The case 11 has a rectangular parallelepiped shape, and the electrode assembly 12 has a rectangular parallelepiped shape according to the case 11. The secondary battery 10 is a square lithium ion battery.

  As shown in FIG. 3, the electrode assembly 12 includes a plurality of positive electrodes 21 having a rectangular sheet shape and a plurality of negative electrodes 31 having a rectangular sheet shape. The positive electrode 21 and the negative electrode 31 are electrodes having different polarities. The positive electrode 21 includes a positive metal foil (aluminum foil in the present embodiment) 21a and a positive electrode active material layer 21b present on both surfaces of the positive metal foil 21a. The negative electrode 31 includes a negative electrode metal foil (copper foil in this embodiment) 31a and a negative electrode active material layer 31b present on both surfaces of the negative electrode metal foil 31a. The electrode assembly 12 is a laminated type having a layered structure in which separators 24 are interposed between a plurality of positive electrodes 21 and a plurality of negative electrodes 31. The separator 24 insulates the positive electrode 21 and the negative electrode 31. The stacking direction of the positive electrode 21 and the negative electrode 31 is the short direction of the lid 14 in the case 11.

  The positive electrode 21 has a tab 25 having a shape protruding from a part of one side of the positive electrode 21. The negative electrode 31 has a tab 35 having a shape protruding from a part of one side of the negative electrode 31. The plurality of positive electrode tabs 25 and the plurality of negative electrode tabs 35 do not overlap each other in a state where the positive electrode 21 and the negative electrode 31 are laminated. The electrode assembly 12 has a tab-side end face 12b from which the tabs 25 and 35 protrude.

  As shown in FIG. 1, the secondary battery 10 includes a positive electrode tab group 26 having a shape protruding from the tab-side end surface 12 b. The positive electrode tab group 26 is configured by collecting and stacking all the positive electrode tabs 25 on one end side in the stacking direction of the electrode assembly 12. The secondary battery 10 includes a negative electrode tab group 36 having a shape protruding from the tab-side end surface 12b. The negative electrode tab group 36 is configured by collecting and stacking all the negative electrode tabs 35 on one end side in the stacking direction of the electrode assembly 12. The positive electrode tab group 26 and the negative electrode tab group 36 exist on the tab-side end surface 12b, which is the same end surface.

  The secondary battery 10 includes a positive electrode conductive member 41. The positive electrode conductive member 41 has a rectangular plate shape with the length extending in the longitudinal direction of the lid body 14. A positive electrode tab group 26 is joined to one end in the longitudinal direction of the positive electrode conductive member 41. A positive electrode terminal 42 is joined to the other end in the longitudinal direction of the positive electrode conductive member 41.

  The secondary battery 10 includes a negative electrode conductive member 51. The negative electrode conductive member 51 is in the shape of a rectangular plate whose length extends in the longitudinal direction of the lid body 14. A negative electrode tab group 36 is joined to one end side in the longitudinal direction of the negative electrode conductive member 51. A negative electrode terminal 52 is joined to the other end side in the longitudinal direction of the negative electrode conductive member 51. The positive electrode conductive member 41 and the negative electrode conductive member 51 are interposed between the inner surface 14a of the lid 14 and the tab side end surface 12b of the electrode assembly 12 facing the inner surface 14a.

  The positive electrode conductive member 41 and the negative electrode conductive member 51 are juxtaposed along the surface direction of the lid body 14. The surface direction of the lid body 14 is a direction along the inner surface 14a of the lid body 14. In the present embodiment, the positive electrode conductive member 41 and the negative electrode conductive member 51 are arranged in the longitudinal direction of the lid body 14 which is one of the surface directions of the lid body 14. Therefore, the side-by-side direction X of the positive electrode conductive member 41 and the negative electrode conductive member 51 is also the longitudinal direction of the lid body 14. The direction along the surface direction of the lid body 14 and perpendicular to the parallel direction X is the stacking direction Y of the positive electrode 21 and the negative electrode 31 and is the short direction of the lid body 14.

  As shown in FIG. 4, the positive electrode conductive member 41 and the negative electrode conductive member 51 are juxtaposed with a gap in the juxtaposition direction X. The positive electrode conductive member 41 and the negative electrode conductive member 51 arranged in the parallel direction X are positioned at the same height, and the tip of the positive electrode conductive member 41 and the tip of the negative electrode conductive member 51 are opposed to each other. The positive electrode conductive member 41 includes a positive electrode side end surface 41a at the tip, and the negative electrode conductive member 51 includes a negative electrode side end surface 51a at the tip. The positive electrode side end surface 41a and the negative electrode side end surface 51a face each other in the juxtaposed direction X, and the dimension between the positive electrode side end surface 41a and the negative electrode side end surface 51a in the juxtaposed direction X is the interval L1.

  As shown in FIG. 1, the positive electrode terminal 42 and the negative electrode terminal 52 pass through the lid body 14 and a part thereof is exposed outside the case 11. In addition, ring-shaped insulating members 17 a for insulating from the case 11 are attached to the positive terminal 42 and the negative terminal 52, respectively.

  The secondary battery 10 includes a pressure release valve 18 in a lid body 14 as a wall portion. The pressure release valve 18 is cleaved when the pressure in the case 11 reaches an open pressure that is a predetermined pressure. The pressure in the case 11 is released outside the case 11 by the cleavage of the pressure release valve 18.

  The release pressure of the pressure release valve 18 is set to a pressure at which the case 11 itself or the joint portion between the case body 13 and the lid body 14 can be broken before a crack or breakage can occur. The pressure release valve 18 has a thin plate-like valve body 19 that is thinner than the plate thickness of the lid body 14. The valve body 19 is positioned at the bottom of the recess 20 formed in the outer surface 14 b positioned outside the case 11 out of both surfaces of the lid 14, and is formed integrally with the lid 14.

  The pressure release valve 18 is located closer to the positive electrode terminal 42 than the center of the lid body 14 in the longitudinal direction. Further, the pressure release valve 18 is located at the center of the lid 14 in the short direction. In a plan view of the lid body 14 as viewed from the outer surface 14b, the pressure release valve 18 has a long hole shape.

  As shown in FIG. 1, FIG. 4 or FIG. 5, the secondary battery 10 includes a shielding member 60. The shielding member 60 is disposed between the positive electrode conductive member 41 and the negative electrode conductive member 51 as a pair of conductive members in the parallel direction X (longitudinal direction of the lid body 14).

  The shielding member 60 is disposed between the inner surface 14a of the lid body 14 and the tab side end surface 12b, and is placed on the tab side end surface 12b. The shielding member 60 is made of a resin having heat resistance and insulation. For this reason, the shielding member 60 does not short-circuit the positive potential member and the negative potential member in the case 11.

  The shielding member 60 includes a rectangular plate-shaped shielding part 61. The shielding part 61 has a rectangular plate shape when viewed from the outer surface 14 b of the lid body 14. The shielding part 61 has a shape in which the long side extends in the side-by-side direction X and the short side extends in the stacking direction Y. The shielding part 61 includes a first short edge part 61 d at the edge part near the positive electrode conductive member 41 in the juxtaposed direction X, and a second short edge part 61 f at an edge part near the negative electrode conductive member 51.

  The shielding member 60 includes an opening 61 b aligned with the shielding portion 61 in the juxtaposed direction X on the bottom side of the shielding member 60. In a plan view of the lid body 14 as viewed from the outer surface 14b, the opening 61b is adjacent to the second short edge portion 61f of the shielding portion 61 along the juxtaposed direction X and exposes the tab side end surface 12b.

  As shown in FIG. 4, the dimension M1 of the shielding part 61 in the juxtaposed direction X, that is, the dimension from the first short edge part 61d to the second short edge part 61f along the juxtaposed direction X is the positive electrode conductive member 41. And the distance L1 between the negative electrode conductive member 51 is shorter. Moreover, the dimension M1 of the shielding part 61 is longer than the dimension of the pressure release valve 18 in the parallel direction X. The dimension of the shielding part 61 in the stacking direction Y is longer than the dimension of the pressure release valve 18 in the stacking direction Y. The shield 61 covers the entire pressure release valve 18 from the electrode assembly 12 side.

  The shielding member 60 includes first ribs 62 having a shape standing from the pair of long edges extending in the parallel direction X toward the lid body 14. The first ribs 62 have a shape that extends in the parallel direction X. The dimension of the first ribs 62 in the side-by-side direction X is slightly shorter than the distance L1 between the conductive members 41 and 51. The shielding member 60 is supported by the tab side end surface 12b in a state where the first rib 62 is accommodated between the positive electrode side end surface 41a and the negative electrode side end surface 51a.

  The outer surface of one first rib 62 can be in contact with the inner surface of one long side wall 13d of the case body 13, and the outer surface of the other first rib 62 can be in contact with the inner surface of the other long side wall 13d. is there. The shielding member 60 is in a state of being separated from the inner surface of each long side wall 13 d that is the inner surface of the case 11. However, when the shielding member 60 moves slightly in the stacking direction Y, it immediately comes into contact with any of the long side walls 13d. For this reason, the movement of the shielding member 60 in the stacking direction Y is restricted.

  The first short edge portion 61d of the shielding portion 61 is closer to the positive electrode conductive member 41 than the pressure release valve 18 in the juxtaposed direction X, and the second short edge portion 61f of the shielding portion 61 is pressure relieved in the juxtaposed direction X. It is closer to the negative electrode conductive member 51 than the valve 18. In the juxtaposed direction X, the second short edge portion 61f is located farther from the pressure release valve 18 than the first short edge portion 61d. Therefore, the opening 61b aligned with the second short edge 61f is also farther from the pressure release valve 18 than the first short edge 61d.

  Each of the first ribs 62 includes a portion protruding from the second short edge portion 61f of the shielding portion 61 toward the opening 61b side (the negative electrode conductive member 51 side). Each of the first ribs 62 includes a protruding portion 66 at a portion protruding from the second short edge portion 61f. The protrusion 66 of one first rib 62 and the protrusion 66 of the other first rib 62 face each other in the stacking direction Y.

  The shielding member 60 includes a first abutment portion 67 at each protrusion 66. The first abutting portion 67 is located at the tip portion near the negative electrode conductive member 51 in each protruding portion 66. The first contact portions 67 are plate-like shapes that protrude toward the protruding portions 66 that face each other. In a plan view as viewed from the outer surface 14 b of the lid body 14, the protruding direction of the first contact portion 67 from the protruding portion 66 is orthogonal to the longitudinal direction of the first rib 62. Further, the first contact portions 67 are respectively in the immediate vicinity of the negative electrode side end surface 51 a of the negative electrode conductive member 51.

  In a plan view of the shielding member 60 viewed from the outer surface 14b of the lid body 14, the opening 61b is surrounded by the second short edge portion 61f, the pair of protrusions 66, and a part of the negative electrode side end surface 51a. . In plan view, the opening 61b is closer to the shielding part 61 than the first contact part 67 in the parallel direction X.

  Each first contact portion 67 includes a contact surface 67a on a surface facing the negative electrode side end surface 51a in the parallel direction X. Each first contact portion 67 is in a position where the contact surface 67a can contact the negative electrode side end surface 51a. Therefore, in the present embodiment, the negative electrode conductive member 51 is one conductive member. Each first abutment portion 67 has a shape that projects from the position closer to the lid body 14 than the shielding portion 61 and the opening portion 61 b toward the projecting portion 66 facing each first rib 62.

  The shielding member 60 includes a second rib 63. The second rib 63 has a plate shape that is erected from the first short edge portion 61 d of the shielding portion 61 toward the lid body 14. The pair of first ribs 62 and second ribs 63 are connected to each other. The protruding end of the second rib 63 is at a position beyond the positive electrode conductive member 41 to the lid body 14 side. For this reason, the positive electrode side end surface 41 a of the positive electrode conductive member 41 faces the outer surface of the second rib 63 and can contact. Therefore, in this embodiment, the positive electrode conductive member 41 is the other conductive member, and the second rib 63 is the second contact portion.

  As shown in FIG. 5, in the shielding member 60, among the dimensions along the standing direction of the first rib 62 from the shielding part 61, the dimension of the first rib 62 from the outer surface 61a of the shielding part 61 is the standing distance H1. And In the shielding member 60, the dimension from the outer surface 61a of the shielding part 61 among the dimensions along the standing direction of the second rib 63 from the shielding part 61 is defined as the standing distance H2. The standing distance H <b> 2 of the second rib 63 is shorter than the standing distance H <b> 1 of the first rib 62. This is to secure a flow path for the gas flowing from the positive electrode conductive member 41 side toward the pressure release valve 18.

  As shown in FIG. 4, in the shielding member 60 placed on the tab-side end surface 12 b, the pair of first ribs 62 is located in the stacking direction Y among the locations surrounding the pressure release valve 18 on the inner surface 14 a of the lid body 14. It is possible to contact the outside of the pressure release valve 18. The second rib 63 is located on the outer side closer to the positive electrode conductive member 41 than the pressure release valve 18 in the parallel direction X. Therefore, the 1st rib 62 and the 2nd rib 63 exist in the position which does not overlap with the pressure release valve 18 in the planar view which looked at the cover body 14 from the outer surface 14b. When the shielding member 60 moves toward the lid body 14, the first rib 62 contacts the inner surface 14 a of the lid body 14. The shielding part 61 and the lid body 14 are separated by this contact.

  The dimension of the opening 61b in the parallel direction X is defined as an opening width M2. The opening width M2 of the opening 61b is a straight line that connects the second short edge portion 61f of the shielding portion 61 and the first contact portion 67 with the shortest distance in a plan view of the lid body 14 when viewed from the outer surface 14b. It's about length.

  The dimension M1 of the shielding part 61 and the opening width M2 of the opening part 61b are such that when the gas generated during the nail penetration test bends at the second short edge part 61f of the shielding part 61 toward the pressure relief valve 18, Many are set so that they can flow directly into the pressure relief valve 18. That is, after the gas is bent at the second short edge portion 61f, the gas is set so as not to collide with a portion adjacent to the pressure release valve 18 in the lid body 14.

  As shown in FIG. 6, the nail penetration test is performed by inserting a nail into the central portion P in the front view of the electrode assembly 12. As shown by the arrow G, the gas rises straight from the center of the electrode assembly 12 toward the pressure relief valve 18. The gas collides with the outer surface 61a of the shield 61 and changes its direction along the outer surface 61a.

  A part of the gas rises along the outer surface of the second rib 63, bends at the protruding end of the second rib 63, and reaches the pressure release valve 18. Further, part of the gas is directed to the opening 61 b, bent at the second short edge portion 61 f of the shielding portion 61, and reaches the pressure release valve 18. Further, the other gas rises along the outer surface of the first rib 62, flows between the protruding end of the first rib 62 and the inner surface 14 a of the lid body 14, and reaches the pressure release valve 18.

  With regard to such a gas flow path, the opening 61b is wider than the gas flow path defined between the protruding ends of the first rib 62 and the second rib 63 and the lid body 14. For this reason, most of the gas flows into the opening 61 b and reaches the pressure release valve 18. The gas flowing into the opening 61b bends at the second short edge portion 61f of the shielding portion 61. Here, the closer the second short edge portion 61f is to the negative electrode conductive member 51 along the side-by-side direction X, the sharper the angle at which the gas is bent to go to the pressure release valve 18, and the gas becomes the lid 14 It becomes easy to collide with the part adjacent to the pressure release valve 18 in FIG.

  The position of the second short edge portion 61f, that is, the dimension M1 of the shielding portion 61 and the opening width M2 of the opening portion 61b are set by experiments or the like so that the gas does not collide with the portion adjacent to the pressure release valve 18 in the lid body 14. doing.

Next, the operation of the secondary battery 10 will be described.
As shown in FIG. 6, when a nail is inserted into the central portion P of the case 11 in a front view of the secondary battery 10 in order to perform a nail penetration test, the nail penetrates the electrode assembly 12 in the stacking direction. . Then, the separator 24 between the positive electrode 21 and the negative electrode 31 is broken or melted via the nail, and the positive electrode 21 and the negative electrode 31 are short-circuited in the case 11.

  When a short circuit occurs in the electrode assembly 12, heat is generated around the short circuit part, and the electrolyte component is decomposed to generate gas. Due to the generation of gas, the pressure in the secondary battery 10 increases. When the internal pressure of the case 11 reaches the open pressure of the pressure release valve 18, the valve body 19 of the pressure release valve 18 is cleaved and the gas in the case 11 is released to the outside of the case 11.

  The high-pressure gas generated in the short-circuit portion rises straight toward the cleaved pressure release valve 18. Moreover, a part of each electrode 21 and 31 is stripped off by the generated gas. The gas toward the pressure release valve 18 exits the electrode assembly 12 from the tab side end face 12b. Then, the gas collides with the outer surface 61a of the shielding part 61 and changes its direction along the outer surface 61a.

  A part of the gas whose direction is changed due to the collision with the shielding part 61 rises along the first rib 62 and the second rib 63, and a gap between the tip surface of each rib 62, 63 and the inner surface 14 a of the lid body 14. Through to the pressure relief valve 18. Further, most of the gas flows into the opening 61b. The gas flowing into the opening 61b bends at the second short edge portion 61f and changes its direction to the pressure release valve 18. Thereafter, the gas is discharged out of the case 11 from the cleaved pressure release valve 18.

  Even if the gas collides with the shielding part 61 or each of the ribs 62 and 63, the positive electrode side end face 41a and the outer surface of the second rib 63 abut, and the negative electrode side end face 51a and the abutment surface 67a of the first abutment part 67. Movement of the shielding member 60 in the juxtaposed direction X is restricted. Further, the movement of the shielding member 60 in the stacking direction Y is restricted by the contact between the outer surface of each first rib 62 and the inner surface of each long side wall 13d.

According to the above embodiment, the following effects can be obtained.
(1) The shielding member 60 includes an opening 61 b adjacent to the shielding part 61, and since the opening 61 b is present, the dimension M 1 of the shielding part 61 is a distance between the positive electrode conductive member 41 and the negative electrode conductive member 51. It is shorter than L1. Therefore, by providing the opening 61b, the position where the gas bends toward the pressure release valve 18 can be brought close to the pressure release valve 18 in the parallel direction X. Then, by adjusting the dimension M1 of the shielding part 61 and the opening width M2 of the opening part 61b, adjusting the position of the second short edge part 61f of the shielding part 61, and adjusting the angle at which the gas is bent, the gas pressure is increased. It can flow directly into the release valve 18. As a result, it is possible to prevent the gas bent at the second short edge portion 61f of the shielding portion 61 from colliding with the portion adjacent to the pressure release valve 18 in the lid body 14 and to prevent the lid body 14 from being melted by the gas. it can.

  (2) The shielding member 60 includes a second rib 63 that contacts the positive electrode side end surface 41a, and includes a first contact part 67 that contacts the negative electrode side end surface 51a. The movement of the shielding member 60 in the juxtaposed direction X can be restricted by the first contact portion 67 and the second rib 63. As a result, the position of the shielding part 61 and the opening 61b with respect to the pressure release valve 18 can be maintained, and the gas can be prevented from colliding with the lid body 14.

  (3) The shielding member 60 includes the second rib 63 on the first short edge portion 61 d near the positive electrode conductive member 41 in the shielding portion 61. The second rib 63 abuts on the positive electrode side end surface 41 a and restricts the movement of the shielding member 60. For this reason, the protruding end of the second rib 63 is closer to the lid body 14 than the positive electrode conductive member 41. As a result, the second rib 63 constricts the gas flow path from the positive electrode conductive member 41 side to the pressure release valve 18, and the gas becomes easier to flow to the opening 61 b.

  (4) Each first rib 62 includes a protruding portion 66 that protrudes along the juxtaposed direction X toward the opening 61b from the second short edge portion 61f. The first contact portion 67 is formed at the tip of the protrusion 66 near the negative electrode conductive member 51. For this reason, even if the shielding member 60 includes the first contact portion 67, the first contact portion 67 is in a position where the opening 61b is widened to the maximum. Therefore, it is possible to minimize the hindering of the gas flow by the first contact portion 67.

  (5) The second rib 63 is located closer to the positive electrode conductive member 41 in the shielding member 60. For this reason, even if a part of the positive electrode conductive member 41 made of aluminum or the tab 25 is melted or scraped off by high-temperature and high-pressure gas, it is discharged out of the case 11 by colliding with the second rib 63. Can be suppressed.

  (6) The 1st rib 62 of the shielding member 60 contacts the inner surface 14a of the cover body 14, maintains the state which separated the shielding part 61 and the cover body 14, and maintains the space | interval of both surfaces. For this reason, even if it is the structure by which the shielding member 60 was mounted in the tab side end surface 12b, the gas flow path is ensured and the gas discharge function from the pressure release valve 18 out of the case 11 can be maintained.

  (7) The pair of first ribs 62 of the shielding member 60 contacts the outside of the pressure release valve 18 in the stacking direction Y on the inner surface 14a of the lid body 14. For this reason, the first rib 62 does not block the pressure release valve 18.

  (8) The first rib 62 of the shielding member 60 is located outside the pressure release valve 18 in the stacking direction Y. During the nail penetration test, the electrode assembly 12 expands in the stacking direction due to a temperature rise, and the gas flows from both sides of the electrode assembly 12 in the stacking direction Y toward the pressure release valve 18. These gases can collide with the first rib 62, and a part of each electrode 21, 31 can be dropped from the gas.

In addition, you may change the said embodiment as follows.
As shown in FIG. 7, in the shielding member 60, a support protrusion 68 is projected in a plate shape from the second short edge portion 61 f of the shielding portion 61 toward the negative electrode conductive member 51, and the tip end portion of the support protrusion 68 is formed. A plate-like first abutting portion 69 may be provided so as to protrude from the lid toward the lid body 14. In this case, the opening 61b exists between the support protrusion 68 and the first rib 62 in the stacking direction Y and closer to the shielding part 61 than the first contact part 69 in the juxtaposition direction X.

In the form shown in FIG. 7, the first rib 62 may not include the protruding portion 66, and the first rib 62 may exist up to the second short edge portion 61 f of the shielding portion 61.
Furthermore, in the embodiment shown in FIG. 7, the first rib 62 may be omitted.

  ○ The shielding member 60 may be made of metal. When the shielding member 60 is made of metal, an insulating member is interposed between the positive potential member (the positive electrode conductive member 41 and the positive electrode 21) and the negative potential member (the negative electrode conductive member 51 and the negative electrode 31). Let The insulating member may be integrated with one of the charged member and the shielding member 60, or may be integrated with both. The insulating member may be an insulating resin or ceramic coating.

  Alternatively, when the shielding member 60 is made of metal, the shielding member 60 is any of a positive potential member (the positive electrode conductive member 41 and the positive electrode 21) and a negative potential member (the negative electrode conductive member 51 and the negative electrode 31). When contacting one of them, it arrange | positions in the state which does not contact the other.

  One of the tab 25 of the positive electrode 21 and the tab 35 of the negative electrode 31 may have a shape protruding from an end face different from the tab-side end face 12 b in the end face of the electrode assembly 12. In this case, one tab group also exists on an end surface different from the tab-side end surface 12b. The conductive member connected to one tab group has a bent shape from an end surface different from the tab side end surface 12b to the tab side end surface 12b. The tab side end surface 12b is a tab group existing on the tab side end surface 12b. The other conductive member connected and a part of the one conductive member are arranged with a space therebetween.

  In the embodiment, the negative electrode conductive member 51 is one conductive member with which the first contact portion 67 can contact, and the positive electrode conductive member 41 can be contacted with the second rib 63 as the second contact portion. Although it was set as the other electrically-conductive member, it is not restricted to this. When the pressure release valve 18 is close to the negative electrode conductive member 51 along the juxtaposed direction X, the second rib 63 is erected from the short edge near the negative electrode conductive member 51, and the protrusion 66 is connected to the positive electrode conductive member 41. And a first abutting portion 67 that can abut on the positive electrode side end surface 41a. The opening 61 b may be provided closer to the shielding part 61 than the first contact part 67 in the juxtaposed direction X, and the opening 61 b may be disposed closer to the positive electrode conductive member 41.

If the gas can flow directly into the pressure release valve 18, the dimension M1 of the shielding part 61 and the opening width M2 of the opening part 61b may be changed as appropriate.
In the shielding member 60, the first rib 62 may be erected from only one of the long edges of the shielding part 61.

  The second contact portion does not have to be a rib shape like the second rib 63 but has a shape protruding from the shielding portion 61 toward the lid body 14, and is in contact with the positive electrode side end surface 41 a of the positive electrode conductive member 41. A columnar shape protruding from the first short edge portion 61d may be used as long as contact is possible.

The separator 24 may not be a type in which the separator 24 is interposed between the positive electrode 21 and the negative electrode 31 one by one. For example, the separator 24 may be a bag-like separator that accommodates the positive electrode 21.
Alternatively, the separator may have a long shape, and may be a type that is interposed between the positive electrode 21 and the negative electrode 31 by being folded.

  ○ The secondary battery may be cylindrical. A cylindrical secondary battery has a wound electrode assembly in which a strip-shaped positive electrode and a strip-shaped negative electrode are stacked and wound via a separator inside a hollow columnar case. The case is made of metal and has a shape in which one end in the axial direction is closed and the other end is opened. An electrolyte is injected into the case and impregnated in the separator. In addition, the secondary battery includes insulating plates at both axial ends of the electrode assembly.

  The secondary battery includes a lid at the open end of the case, and a pressure release valve provided inside the lid. The secondary battery includes a shielding member that covers the pressure release valve from the electrode assembly side. The shielding member may have the same form as the shielding member of the first embodiment, or the form shown in FIG.

The electrode assembly may be a wound type in which one belt-like positive electrode and one belt-like negative electrode are wound around a winding shaft in a state where they are insulated by a separator.
The power storage device may be another power storage device such as an electric double layer capacitor.

  In embodiment, although the secondary battery 10 was a lithium ion secondary battery, it is not restricted to this, Other secondary batteries, such as nickel hydride, may be sufficient. In short, any ion may be used as long as ions move between the positive electrode active material layer and the negative electrode active material layer and transfer charge.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(1) Each of the pair of first ribs includes a protrusion that protrudes from the edge of the shielding portion toward the opening along the juxtaposed direction, and the first contact portion includes the protrusion The electrical storage apparatus which is the shape protruded in the state which mutually approaches from the front-end | tip part.

  (2) The power storage device, wherein the first contact portion is closer to the wall portion than the opening portion.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as a power storage device, 11 ... Case, 12 ... Electrode assembly, 12b ... Tab side end face as end face, 14 ... Lid as wall part, 14a ... Inner face, 18 ... Pressure release valve, 21 ... Positive electrode as electrode, 24... Separator, 31. Negative electrode as electrode, 41. Positive electrode conductive member as conductive member, 51. Negative electrode conductive member as conductive member, 60... Shield member, 61. Opening part 62 ... 1st rib 63 ... 2nd rib as 2nd contact part, 67 ... 1st contact part.

Claims (3)

An electrode assembly configured in layers with electrodes of different polarities insulated by separators;
An electrolyte,
A case for accommodating the electrode assembly and the electrolyte;
A pressure release valve that is present in the wall portion of the case, cleaves when the pressure in the case reaches an open pressure, and releases the pressure in the case to the outside of the case;
A pair connected to each electrode of each polarity, interposed between the inner surface of the wall portion and the end surface of the electrode assembly facing the inner surface, and arranged in parallel along the end surface of the electrode assembly A power storage device comprising:
A shielding member positioned between the pair of conductive members in the direction in which the pair of conductive members are arranged, and placed on an end surface of the electrode assembly;
The shielding member is
A shielding portion supported on an end face of the electrode assembly in a state of covering the pressure release valve from the electrode assembly side;
A first abutting portion that is integral with the shielding portion and is capable of abutting against one of the conductive members;
A shape projecting from the shielding part toward the wall part, and a second contact part capable of contacting the other conductive member;
An opening for exposing the end face of the electrode assembly in the planar view, in the plan view when the wall is viewed from the outer surface, is located closer to the shielding part than the first contact part in the juxtaposed direction; A power storage device comprising:   The shielding member includes a first rib erected from a pair of edges extending in the juxtaposition direction in the shielding part, and a pair of edges of the shielding part extending in a direction orthogonal to the juxtaposition direction in the shielding part. 2. The power storage device according to claim 1, further comprising: a second rib that is erected from an edge portion near the other conductive member among the portions, wherein the second rib is the second contact portion.   The power storage device according to claim 1, wherein the power storage device is a secondary battery.

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