JP2016046008A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device in which the worsening of sealability of a liquid inlet by a seal member can be suppressed.SOLUTION: A secondary battery 10 comprises: a lid 14; a liquid inlet 20; and ribs 21 provided on the lid. The ribs includes: a first rib 21a closer to a first long edge 14a of the lid 14 than the liquid inlet 20 in a first direction Y1; and a second rib 21b closer to a second long edge 14b. The first rib 21a and the second rib 21b are arrayed in the first direction Y1, and the liquid inlet 20 is sandwiched by them. In plan view of the lid 14, the length of the second rib 21b in its longitudinal direction is longer than that of the first rib 21a in its longitudinal direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power storage device having a liquid injection hole and a rib disposed around the liquid injection hole.

  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. In this type of secondary battery, an electrode assembly in which a positive electrode including a positive electrode active material layer and a negative electrode including a negative electrode active material layer are stacked with a separator interposed therebetween is housed in a case. Further, the lid constituting the wall portion of the case is provided with a liquid injection hole for injecting an electrolytic solution into the case, and the liquid injection hole is sealed by a sealing member after the injection of the electrolytic solution. (For example, refer to Patent Document 1).

JP 2000-182591 A

  However, in the secondary battery, when the reaction of the electrode assembly proceeds excessively due to gas generation accompanying initial charging during conditioning or overcharging, gas is generated inside the case and accumulated, and the internal pressure of the case is increased. May rise abnormally. In this case, there is a possibility that the pressure in the case acts on the wall portion of the case, and stress is generated in each wall portion to deform the wall portion. If the lid of the wall portion is deformed, the shape of the liquid injection hole may be changed before the stress is generated, or the shape around the liquid injection hole may be changed before the stress is generated. As a result, the sealing performance of the liquid injection hole by the sealing member may be reduced.

  This invention was made paying attention to the problem which exists in such a prior art, The objective is the electrical storage apparatus which can suppress the fall of the sealing performance of the liquid injection hole by a sealing member Is to provide.

  A power storage device for solving the above problems includes a case containing an electrode assembly and an electrolytic solution, a liquid injection hole penetrating a wall portion constituting the case, and a sealing member for sealing the liquid injection hole And at least a pair of ribs arranged around the liquid injection hole in the wall portion, extending along the surface of the wall portion and one of the two directions orthogonal to each other. The direction is set to a direction along a straight line connecting a pair of parallel edges at the shortest distance in the wall, and the other second direction is orthogonal to and parallel to the pair of edges at the wall. A direction along a straight line connecting another pair of edges at the shortest distance is set, and one edge of the pair of edges located on the straight line along the first direction is the first edge, the other When the second edge is the second edge, the liquid injection hole is the second edge in the first direction. The at least one pair of ribs is arranged in the first direction so as to sandwich the liquid injection hole, and the pair of ribs is closer to the first edge than the liquid injection hole. When the rib is a first rib and the rib close to the second edge is a second rib, the longitudinal length of the first rib and the second rib in plan view of the wall portion is: The gist is that the second rib is longer than the first rib.

  According to this, at least a pair of ribs was provided around the liquid injection hole. Of the pair of ribs, the longer second rib is not the first edge close to the liquid injection hole, but the first edge farther from the liquid injection hole. It was provided at a position close to two edges. Therefore, the longer second rib is provided at a position closer to the center of the wall portion in the first direction than the first rib, that is, at a place where the wall portion is easily deformed. Therefore, even if the internal pressure of the case increases and stress is generated in the wall portion, deformation of the portion that is easily deformed in the wall portion can be suitably suppressed by the second rib. As a result, by providing the ribs, the shape of the liquid injection hole and the shape around the liquid injection hole are prevented from changing, and the deterioration of the sealing performance of the liquid injection hole by the sealing member is suppressed. Can do.

  In the power storage device, the wall portion has a rectangular shape in plan view, and the first direction is a short direction perpendicular to the pair of long edge portions of the wall portion, and the first rib and the second The longitudinal direction of the ribs extends along the first direction.

According to this, deformation of the wall portion along the first direction (short direction) can be suitably suppressed by the rib.
In the power storage device, the wall portion has a rectangular shape in plan view, and the first direction is a short direction perpendicular to the pair of long edge portions of the wall portion, and the first rib and the second The longitudinal direction of the rib extends in the longitudinal direction of the wall portion orthogonal to the first direction.

According to this, the deformation of the wall portion along the first direction (longitudinal direction) can be suitably suppressed by the rib.
Further, regarding the power storage device, when one edge portion of another pair of edge portions positioned on a straight line along the second direction is a third edge portion and the other edge portion is a fourth edge portion, The liquid injection hole is disposed at a position closer to the third edge than the fourth edge in the second direction, and further includes a pair of other ribs that sandwich the liquid injection hole along the second direction, Of the pair of other ribs, if another rib closer to the third edge than the liquid injection hole is the third rib and another rib closer to the fourth edge is the fourth rib, the plane of the wall portion In terms of the length in the longitudinal direction of the third rib and the fourth rib as viewed, the fourth rib may be longer than the third rib.

  According to this, among the other ribs, the longer fourth rib is far from the liquid injection hole instead of the third edge close to the liquid injection hole among the third edge and the fourth edge. It was provided at a position close to the fourth edge. Therefore, the longer fourth rib is provided at a position closer to the center of the wall portion in the second direction than the third rib, that is, at a place where the wall portion is easily deformed. Therefore, even if the internal pressure of the case increases and stress is generated in the wall portion, deformation of the portion that is easily deformed in the wall portion can be suitably suppressed by the fourth rib. Therefore, the deformation in both the first direction and the second direction can be suitably suppressed by the ribs.

  A power storage device for solving the above problems includes a case containing an electrode assembly and an electrolytic solution, a liquid injection hole penetrating a wall portion constituting the case, and a sealing member for sealing the liquid injection hole And a rib disposed around the liquid injection hole in the wall portion, extending along the surface of the wall portion and having one first direction out of two directions orthogonal to each other, A direction along a straight line connecting a pair of edges parallel to each other at the shortest distance in the wall, and the other second direction is orthogonal to the pair of edges in the wall and A direction along a straight line connecting a pair of edges at the shortest distance is set, and a line passing through an intermediate point of the wall portion along the first direction is defined as a first center line on the surface of the wall portion. , When a line passing through the intermediate point of the length along the second direction is the second center line, The liquid hole is disposed on a center point of the wall portion where the first center line and the second center line intersect, and a concentric region surrounding the liquid injection hole is divided into four equal parts on the surface of the wall portion. The gist is that there are four regions, and the ribs are arranged in each of the four regions.

  According to this, even when the internal pressure of the case rises and stress is generated in the wall portion, the rib can suppress deformation of the wall portion around the liquid injection hole, and the liquid injection hole is the center point of the wall portion. It may be provided above. As a result, when the electrolytic solution is injected from the liquid injection hole, the electrolytic solution diffuses in each of the first direction and the second direction of the case, so that the electrode assembly can be impregnated with no variation. it can.

  The power storage device is a secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the sealing performance of the injection hole by a sealing member can be suppressed.

The perspective view which shows the external appearance of the secondary battery of 1st Embodiment. The top view which shows a secondary battery. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1 showing the liquid injection hole and the first rib. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1 showing the liquid injection hole and the second rib. The top view which shows the secondary battery of 2nd Embodiment. The top view which shows the secondary battery of 3rd Embodiment. The top view which shows the other example in 3rd Embodiment. The top view which shows the other example in 3rd Embodiment. The top view which shows the other example in 1st Embodiment.

Hereinafter, a first 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 FIG. 2, a secondary battery 10 as a power storage device includes a case 11, an electrode assembly 12 accommodated in the case 11, and an electrolytic solution. The case 11 is a plate-like and rectangular shape in plan view as a wall portion that closes a bottomed cylindrical case body 13 and an opening 13a (see FIG. 3) through which the electrode assembly 12 is inserted into the case body 13. And the lid 14. Both the case main body 13 and the lid body 14 are made of metal (for example, made of stainless steel or aluminum).

  In the secondary battery 10 of this embodiment, the case main body 13 has a bottomed rectangular tube shape, and the lid body 14 has a rectangular flat plate shape. Therefore, the secondary battery 10 is a rectangular battery having an external appearance. . Moreover, the secondary battery 10 of this embodiment is a lithium ion battery. And in the secondary battery 10, the cover body 14 is joined to the opening part 13a of the case main body 13 by welding (for example, laser welding). A welded portion W is formed around the opening 13a of the case body 13 and around the lid body 14 in contact with the opening 13a.

  A positive electrode terminal 15 and a negative electrode terminal 16 for taking out electricity from the electrode assembly 12 are electrically connected to the electrode assembly 12. The positive electrode terminal 15 and the negative electrode terminal 16 are each attached with a ring-shaped insulating ring 17 a for insulating from the case 11.

  The electrode assembly 12 includes a positive electrode and a negative electrode that are electrodes of different polarities, and a separator that insulates the positive electrode and the negative electrode. The positive electrode has a positive electrode active material layer on both surfaces of a positive electrode metal foil (aluminum foil). The negative electrode has a negative electrode active material layer on both surfaces of a negative electrode metal foil (copper foil). The electrode assembly 12 has a stacked structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked and a separator is interposed between the electrodes.

  The secondary battery 10 has a pressure release valve 18 on the lid 14. The pressure release valve 18 is cleaved when the pressure in the case 11 reaches an open pressure, which is a predetermined pressure, so that the pressure in the case 11 does not increase excessively, and the pressure in the case 11 is moved outside the case 11. Open. Further, the secondary battery 10 has a liquid injection hole 20 in the lid body 14, and the liquid injection hole 20 has a circular hole shape in plan view that penetrates the lid body 14 in the thickness direction.

  In the lid body 14, a surface facing the outside of the case 11 is an outer surface 14 e, and a surface facing the inside of the case 11 is an inner surface 14 f (see FIG. 3). A direction extending along the outer surface 14e of the lid 14 and a direction (short direction) along a straight line connecting the pair of long edges at the shortest distance among the pair of parallel edges of the lid 14 is a first. Direction Y1. In the lid body 14, of the pair of long edge portions located on the straight line along the first direction Y <b> 1, one long edge portion is the first long edge portion 14 a as the first edge portion, and the other is the first long edge portion. It is set as the 2nd long edge part 14b as 2 edge parts. Also, a pair of short edges that are another pair of edges that are perpendicular to the first and second long edges 14a and 14b and are parallel to each other in the direction extending along the outer surface 14e of the lid body 14. A direction (longitudinal direction) along a straight line connecting the two at the shortest distance is defined as a second direction Y2. The first direction Y1 and the second direction Y2 are two directions that extend along the outer surface 14e of the lid body 14 and are orthogonal to each other. Then, in the lid body 14, one short edge portion is a first short edge portion 14c as a third edge portion among a pair of short edge portions located on a straight line along the second direction Y2, and the other is a first edge. It is set as the 2nd short edge part 14d as 4 edge parts.

  Further, as shown in FIG. 2, when the line passing through the intermediate point of the length along the first direction Y1 in the lid body 14 is defined as the first center line L1, the liquid injection hole 20 has the first center line L1. Rather than the first long edge portion 14a. That is, the liquid injection hole 20 is located closer to the first long edge portion 14a than the second long edge portion 14b in the first direction Y1. Moreover, when the line which passes the intermediate point of the length along the 2nd direction Y2 in the cover body 14 is made into the 2nd centerline L2, the liquid injection hole 20 is a 1st short edge part rather than the 2nd centerline L2. It is in a position close to 14c. That is, the liquid injection hole 20 is located closer to the first short edge portion 14c than the second short edge portion 14d in the second direction Y2.

  As shown in FIGS. 3 and 4, the liquid injection hole 20 is sealed with a sealing member 30 made of rivets, and leakage of gas and electrolyte from the case 11 is prevented. The sealing member 30 is open at one end in the axial direction and has a hollow cylindrical body 31 having a bottom wall 31a at the other end in the axial direction, and an annular flange provided at the opening edge of the end in the axial direction of the body 31 32 and a mandrel 40 in which the diameter of the body 31 is expanded from the inside.

  The body portion 31 includes a caulking portion 34 whose diameter is expanded by the mandrel 40, and the sealing member 30 is fastened to the lid body 14 by the caulking portion 34 and the flange 32, and the flange portion 32 and the lid body 14 are interposed. Further, the seal member 50 is sandwiched. The seal member 50 is compressed in the thickness direction by the axial force accompanying the fastening, and the liquid injection hole 20 is sealed outside the case 11 by the compressed seal member 50.

  As shown in FIGS. 1 and 2, the secondary battery 10 has four ribs 21 protruding from the outer surface 14 e of the lid body 14, and the ribs 21 are formed when the lid body 14 is press-molded. Of the pair of ribs 21 arranged side by side in the first direction Y1 of the lid body 14, the rib 21 close to the first long edge portion 14a is defined as the first rib 21a, and the rib close to the second long edge portion 14b. 21 is a second rib 21b. The first long edge portion 14a and the second long edge portion 14b sandwich the liquid injection hole 20 in the first direction Y1. Therefore, the first rib 21a is located closer to the first long edge portion 14a than the liquid injection hole 20 in the first direction Y1, and the second rib 21b is the liquid injection hole 20 in the first direction Y1. Rather than the second long edge portion 14b.

  In a plan view of the lid body 14, the longitudinal direction of the first rib 21a and the second rib 21b is along the first direction Y1. Further, when a virtual straight line C1 that passes through the center point of the liquid injection hole 20 and extends along the first direction Y1 is defined, the first rib 21a and the second rib 21b are positioned on the virtual straight line C1. doing. In addition, the first rib 21a and the second rib 21b are at a position equidistant from the liquid injection hole 20 in the first direction Y1. And in the planar view of the cover body 14, the length to the longitudinal direction of the 2nd rib 21b is longer than the length to the longitudinal direction of the 1st rib 21a.

  In the lid body 14, the first rib 21 a is provided over substantially the entire portion along the first direction Y <b> 1 in a portion closer to the second long edge portion 14 b than the first center line L <b> 1. For this reason, in the lid body 14, the rigidity in the first direction Y <b> 1 is enhanced by the second rib 21 b at the site on the second long edge portion 14 b side than the liquid injection hole 20. Further, in the lid body 14, the rigidity in the first direction Y1 is enhanced by the first rib 21a at a portion closer to the first long edge portion 14a than the first center line L1.

  Of the pair of ribs 21 arranged side by side in the second direction Y2 of the lid body 14, the rib 21 closer to the first short edge portion 14c than the liquid injection hole 20 is defined as a third rib 21c, and the liquid injection hole 20 The rib 21 closer to the second short edge portion 14d than the second short edge portion 14d is referred to as a fourth rib 21d. In a plan view of the lid body 14, the longitudinal direction of the third rib 21c and the fourth rib 21d is along the second direction Y2. If a virtual straight line C2 that passes through the center point of the liquid injection hole 20 and extends along the second direction Y2 is defined, the third rib 21c and the fourth rib 21d are positioned on the virtual straight line C2. ing. Further, the third rib 21c and the fourth rib 21d are separated from the liquid injection hole 20 by an equal distance in the second direction Y2. In a plan view of the lid body 14, the lengths of the third rib 21c and the fourth rib 21d in the longitudinal direction are the same. In the lid 14, the rigidity of the portion sandwiching the liquid injection hole 20 in the second direction Y <b> 2 is enhanced by the third rib 21 c and the fourth rib 21 d.

Next, the operation of the secondary battery 10 will be described.
In the secondary battery 10, when the reaction of the electrode assembly 12 proceeds excessively due to gas generation accompanying initial charging during conditioning or overcharging, gas is generated and accumulated in the case 11 and the internal pressure becomes abnormal. To rise. In this case, the pressure in the case 11 acts on each wall portion of the case 11. When the pressure in the case 11 acts on the lid 14 that is a wall, stress is generated in the lid 14. At this time, deformation that curves along the first direction Y1 around the liquid injection hole 20 is suppressed by the first rib 21a and the second rib 21b. The deformation that curves along the second direction Y2 is suppressed by the third rib 21c and the fourth rib 21d.

According to the above embodiment, the following effects can be obtained.
(1) When stress is generated in the lid 14 due to an increase in internal pressure of the case 11, deformation around the liquid injection hole 20 is caused by the first to fourth ribs 21 a to 21 d arranged around the liquid injection hole 20. Can be suppressed. As a result, changes in the shape of the liquid injection hole 20 and the shape of the periphery of the liquid injection hole 20 in the lid 14 can be suppressed. Therefore, it can suppress suitably that a clearance gap produces between the injection hole 20 and the trunk | drum 31 in the sealing member 30, and between the cover body 14 and the sealing member 50, and the sealing member 30 and A decrease in the sealing performance of the liquid injection hole 20 by the seal member 50 can be suppressed.

  (2) The stress generated in the lid body 14 is larger as the center of the lid body 14 in the first direction Y1 and the center of the second direction Y2 are larger. Of the first rib 21a and the second rib 21b arranged in the first direction Y1, the second rib 21b having a longer length in the longitudinal direction is brought closer to the center of the first direction Y1. Arranged. That is, with respect to the first direction Y1 of the lid body 14, the longer second rib 21b was provided at a site formed by only the lid body 14 provided with nothing such as the liquid injection hole 20 or the like. For this reason, the 2nd rib 21b can suppress effectively the deformation | transformation in the site | part which is easy to deform | transform especially around the liquid injection hole 20 at the time of the internal pressure rise of the case 11. Therefore, in the present embodiment, the first rib 21 a and the second rib 21 b are not simply provided, but the position and length at which the effect of the rib 21 can be suitably exerted are specified and provided by the rib 21. The deformation of the lid body 14 around the liquid hole 20 can be suitably suppressed.

  (3) The longitudinal directions of the first rib 21a and the second rib 21b extend in a direction in which deformation is easy in the first direction Y1, and the deformation of the lid body 14 in the first direction Y1 is suitably suppressed. Can do.

  (4) The longitudinal directions of the third ribs 21c and the fourth ribs 21d extend in a direction that is easily deformed in the second direction Y2, and the deformation of the lid body 14 in the second direction Y2 is suitably suppressed. Can do.

  (5) The first to fourth ribs 21 a to 21 d protrude from the outer surface 14 e of the lid body 14 to the outside of the case 11. Therefore, even if the first to fourth ribs 21a to 21d are provided to suppress the deformation of the lid body 14, the space in the case 11 is not narrowed. Therefore, the electrode assembly 12 provided in the case 11 is not reduced, and the battery capacity is not reduced.

(Second Embodiment)
Next, a second embodiment in which the power storage device is embodied as a secondary battery will be described with reference to FIG. In the second embodiment, detailed description of the same parts as those in the first embodiment is omitted.

  As shown in FIG. 5, the secondary battery 10 has two ribs 22 protruding from the outer surface 14 e of the lid body 14, and the ribs 22 are formed when the lid body 14 is press-molded. Of the pair of ribs 22 arranged in the first direction Y1 of the lid body 14, the rib 21 closer to the first long edge portion 14a than the liquid injection hole 20 is defined as the first rib 22a, and the liquid injection hole 20 is provided. The rib 22 closer to the second long edge portion 14b is referred to as a second rib 22b. Therefore, the second rib 22b is located closer to the center in the second direction Y2 than the first rib 22a. In a plan view of the lid body 14, the longitudinal direction of the first rib 22a and the second rib 22b is along the second direction Y2.

  The first rib 22a and the second rib 22b are located on an imaginary straight line C1 that passes through the center point of the liquid injection hole 20 and extends along the first direction Y1. In addition, the first rib 22a and the second rib 22b are in a position sandwiching the liquid injection hole 20 along the first direction Y1, and the first rib 22a and the second rib 22b are in the first direction. In Y1, it is equidistant from the injection hole 20. And in the planar view of the cover body 14, the length to the longitudinal direction of the 2nd rib 22b is longer than the length to the longitudinal direction of the 1st rib 22a.

Therefore, according to the second embodiment, in addition to the effects described in the first embodiment, the following effects can be obtained.
(6) The length of the second rib 22b in the longitudinal direction is longer than the length of the first rib 22a in the longitudinal direction. In other words, the first rib 22a close to the first long edge portion 14a is shortened. Therefore, when the welding jig is brought into contact with the outer surface 14e of the lid body 14 in order to weld the lid body 14 to the case body 13, the first rib 22a and the second rib 22b have the same length. In comparison, it is possible to suppress a decrease in heat absorption in the vicinity of the first long edge portion 14a. As a result, the welding part W can be formed suitably and generation | occurrence | production of the welding defect of the case main body 13 and the cover body 14 can be suppressed.

(Third embodiment)
Next, a third embodiment in which the power storage device is embodied as a secondary battery will be described with reference to FIG. In the third embodiment, detailed description of the same parts as those in the first embodiment is omitted.

  As shown in FIG. 6, the center point P1 of the liquid injection hole 20 is along the first center line L1 passing through the intermediate point of the length along the first direction Y1 in the lid body 14, and along the second direction Y2. It is on the intersection with the second center line L2 passing through the intermediate point of the length. That is, the center point P <b> 1 of the liquid injection hole 20 is located at the center point of the lid body 14. The liquid injection hole 20 is located at a position equidistant from the first long edge portion 14a and the second long edge portion 14b along the first direction Y1, and the first short edge portion 14c along the second direction Y2. And at the same distance from the second short edge portion 14d.

  In the outer surface 14e of the lid body 14, when the concentric area surrounding the liquid injection hole 20 is divided into four equal parts, if the four areas in the outer surface 14e of the lid body 14 are divided areas Ra, the secondary battery 10 is divided into the divided areas Ra. The region Ra has ribs, and four ribs are provided around the liquid injection hole 20 at regular intervals.

  The two ribs arranged in the first direction Y1 with the liquid injection hole 20 in between are referred to as a first direction rib 23a, and the two ribs arranged in the second direction Y2 are referred to as a second direction rib 23b. The longitudinal direction of the two first direction ribs 23a extends in the first direction Y1. The lengths of the two first direction ribs 23a along the first direction Y1 are the same. Moreover, the longitudinal direction of the two second direction ribs 23b extends in the second direction Y2. The lengths of the two second direction ribs 23b along the second direction Y2 are the same. Moreover, all the lengths along the longitudinal direction of the four ribs are the same.

Therefore, according to the third embodiment, the following effects can be obtained in addition to the effects described in the first embodiment.
(7) When stress is generated in the lid 14 due to an increase in the internal pressure of the case 11, the deformation around the liquid injection hole 20 is suppressed by the four ribs 23 a and 23 b arranged around the liquid injection hole 20. Can do. As a result, even if the liquid injection hole 20 is on the center point of the lid 14, deformation of the liquid injection hole 20 and its surroundings is suppressed, and the sealing performance of the liquid injection hole 20 by the sealing member 30 is reduced. Can be suppressed.

  When the liquid injection hole 20 is on the center point of the lid body 14, the distance from the liquid injection hole 20 to the first long edge part 14a along the first direction Y1 is the same as the distance to the second long edge part 14b. Thus, the distance from the liquid injection hole 20 to the first short edge portion 14c along the second direction Y2 is the same as the distance from the second short edge portion 14d. For this reason, when the electrolytic solution is injected into the case 11 from the liquid injection hole 20, the electrolytic solution can be impregnated without variation along the first direction Y1 and the second direction Y2.

In addition, you may change this embodiment as follows.
In 3rd Embodiment, as shown in FIG. 7, you may provide the annular rib 24 so that the injection hole 20 may be surrounded. When configured in this manner, an arc-shaped portion obtained by dividing the annular rib 24 into four equal parts is disposed in the four divided regions Ra.

  In the third embodiment, as shown in FIG. 8, the longitudinal direction of the first direction rib 23a extends in the second direction Y2, and the longitudinal direction of the second direction rib 23b extends in the first direction Y1. You may do it. Even if comprised in this way, the 1st direction rib 23a or the 2nd direction rib 23b is arrange | positioned in each division area Ra.

  In the third embodiment, the first direction ribs 23a may have different lengths along the longitudinal direction of the lid body 14 in plan view, and the second direction ribs 23b may have different lengths of the lid body 14. The lengths in the longitudinal direction in plan view may be different. Further, the first direction ribs 23a and the second direction ribs 23b may all have different lengths in the longitudinal direction.

  In the second embodiment, in addition to the first rib 22a and the second rib 22b, a third rib and a fourth rib arranged side by side in the second direction Y2 may be provided. In this case, the longitudinal direction of the third rib and the fourth rib may be along the first direction Y1, or may be along the second direction Y2. In addition, the third rib and the fourth rib may have a length in the longitudinal direction of the fourth rib that is closer to the center of the second direction Y2 than the third rib.

In the first embodiment, the lengths of the third rib 21c and the fourth rib 21d in the longitudinal direction may be different.
As shown in FIG. 9, the third rib 21 c is a rib closer to the first short edge portion 14 c (third edge portion) than the liquid injection hole 20, and the fourth rib 21 d is more than the liquid injection hole 20. The rib is close to the second short edge portion 14d (fourth edge portion). The length in the longitudinal direction of the fourth rib 21d in plan view of the lid body 14 may be longer than the length in the longitudinal direction of the third rib 21c.

Or you may make the length to the longitudinal direction of the 4th rib 21d in planar view of the cover body 14 shorter than the length to the longitudinal direction of the 3rd rib 21c.
In the first embodiment, the longitudinal direction of the first rib 21a and the second rib 21b does not coincide with the first direction Y1, and the longitudinal direction of the first rib 21a and the second rib 21b. The direction may extend slightly deviating from the first direction Y1.

In the first embodiment, only the first rib 21a and the second rib 21b are provided on the lid body 14, and the third rib 21c and the fourth rib 21d may be omitted.
In the first embodiment, the ribs provided on the lid body 14 may be only a pair of ribs that sandwich the liquid injection hole 20 along the longitudinal direction of the lid body 14. In this case, the longitudinal direction of the lid body 14 is the first direction, and of the pair of parallel edges, the first short edge 14c is the first edge and the second short edge 14d is the second edge. Part.

  Of the pair of ribs that sandwich the liquid injection hole 20 in the longitudinal direction (first direction) of the lid body 14, the rib is closer to the first short edge portion 14 c than the liquid injection hole 20 (first implementation). In the embodiment, the third rib 21c) is the first rib, and the rib close to the second short edge portion 14d (the fourth rib 21d in the embodiment) is the second rib. And the length to the longitudinal direction of the 2nd rib (4th rib 21d) by planar view of the cover body 14 is made longer than the length to the longitudinal direction of the 1st rib (3rd rib 21c). .

In each embodiment, the rib may be provided on the inner surface 14 f of the lid body 14.
In the first embodiment, the surface of the lid body 14 provided with the first rib 21a and the second rib 21b is different from the surface of the lid body 14 provided with the third rib 21c and the fourth rib 21d. May be. For example, the first rib 21 a and the second rib 21 b may be provided on the outer surface 14 e of the lid body 14, and the third rib 21 c and the fourth rib 21 d may be provided on the inner surface 14 f of the lid body 14.

O The side wall and bottom wall which comprise the case main body 13 may be used as the wall part of the case 11, the liquid injection hole 20 may be provided in them, and you may seal with the sealing member 30.
A member other than a rivet, such as a bolt member, may be employed as the sealing member.

A foil made of a metal other than aluminum may be adopted as the metal foil for the positive electrode, and a foil made of a metal other than copper may be adopted as the metal foil for the negative electrode.
The positive electrode may have a structure having a positive electrode active material layer only on one side, or the negative electrode may have a structure having a negative electrode active material layer only on one side.

The electrode assembly 12 may be a wound type.
The secondary battery 10 is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery. In short, any ion may be used as long as ions move between the positive electrode active material and the negative electrode active material and charge is transferred.

  ○ The shape of the case 11 may be changed. For example, the case may have a square shape including a lid body having a square shape in plan view. In this case, in the lid body 14, the lengths along the first direction Y1 and the second direction Y2 are the same. Further, the case may be a cylindrical type provided with a lid having a circular shape in plan view. In this case, in the lid body 14, the lengths along the first direction Y1 and the second direction Y2 are the same. Further, the case may be a cylindrical type having a lid body having an elliptical shape in plan view.

  The present invention may be embodied in a power storage device such as an electric double layer capacitor.

  L1 ... first center line, L2 ... second center line, Ra ... divided region as four regions, Y1 ... first direction, Y2 ... second direction, 10 ... secondary battery as a power storage device, 11 ... Case, 12 ... Electrode assembly, 14 ... Lid as wall, 14a ... First long edge as first edge, 14b ... Second long edge as second edge, 14c ... Third edge First short edge as part, 14d Second short edge as fourth edge, 20 Liquid injection hole, 21a, 22a First rib, 21b, 22b Second rib, 21c 3 ribs, 21d ... 4th rib, 23a ... 1st direction rib as a rib, 23b ... 2nd direction rib as a rib, 24 ... annular rib, 30 ... sealing member.

Claims (6)

A case containing an electrode assembly and an electrolyte; and
A liquid injection hole penetrating a wall portion constituting the case;
A sealing member for sealing the liquid injection hole;
Having at least a pair of ribs arranged around the liquid injection hole in the wall,
A first direction of two directions extending along the surface of the wall portion and orthogonal to each other is set as a direction along a straight line connecting a pair of parallel edges at the shortest distance in the wall portion. The other second direction is set to a direction along a straight line connecting another pair of edges perpendicular to and parallel to the pair of edges at the wall,
When one edge of the pair of edges located on the straight line along the first direction is a first edge and the other edge is a second edge, the liquid injection hole is the first edge. In a direction closer to the first edge than the second edge in the direction of
At least a pair of ribs are lined up in the first direction and sandwich the liquid injection hole. Of the pair of ribs, a rib closer to the first edge than the liquid injection hole is defined as the first rib and the second edge. When the near rib is the second rib, the length of the first rib and the length of the second rib in the longitudinal direction of the wall portion in the plan view is longer than the first rib. A power storage device characterized by being longer.   The wall portion has a rectangular shape in plan view, and the first direction is a short direction perpendicular to the pair of long edge portions of the wall portion, and the longitudinal direction of the first rib and the second rib is The power storage device according to claim 1, wherein the power storage device extends along the first direction.   The wall portion has a rectangular shape in plan view, and the first direction is a short direction perpendicular to the pair of long edge portions of the wall portion, and the longitudinal direction of the first rib and the second rib is The power storage device according to claim 1, wherein the power storage device extends in a longitudinal direction of a wall portion orthogonal to the first direction. When one edge of another pair of edges positioned on the straight line along the second direction is the third edge and the other edge is the fourth edge, the liquid injection hole is In the direction of 2 is located closer to the third edge than the fourth edge,
It further has a pair of other ribs that sandwich the liquid injection hole along the second direction, and among the pair of other ribs, another rib closer to the third edge than the liquid injection hole is the third rib. If another rib close to the fourth edge is a fourth rib, the length of the third rib in the plan view of the wall and the length of the fourth rib in the longitudinal direction is the fourth rib. The power storage device according to any one of claims 1 to 3, wherein is longer than the third rib. A case containing an electrode assembly and an electrolyte; and
A liquid injection hole penetrating a wall portion constituting the case;
A sealing member for sealing the liquid injection hole;
A rib disposed around the liquid injection hole in the wall portion,
A first direction of two directions extending along the surface of the wall portion and orthogonal to each other is set as a direction along a straight line connecting a pair of parallel edges at the shortest distance in the wall portion. The other second direction is set to a direction along a straight line connecting another pair of edges perpendicular to and parallel to the pair of edges at the wall,
On the surface of the wall portion, a line passing through the intermediate point of the length along the first direction in the wall portion is defined as a first center line, and a line passing through the intermediate point of the length along the second direction. Is the second centerline,
The liquid injection hole is disposed on a center point of a wall portion where the first center line and the second center line intersect,
On the surface of the wall portion, there are four regions obtained by dividing a concentric region surrounding the liquid injection hole into four equal parts, and the rib is disposed in each of the four regions. .   The power storage device according to any one of claims 1 to 5, wherein the power storage device is a secondary battery.