JP2014011114A - Power storage device and manufacturing method of electrode assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device in which positional deviation of each separator constituting an electrode assembly can be confirmed easily, and to provide a manufacturing method for electrode assembly.SOLUTION: A secondary battery includes an electrode assembly 14 constituted by laminating a plurality of rectangular positive electrode sheets 21 and a plurality of negative electrode sheets 22 while sandwiching a rectangular separator 23. The separators 23 have the same shape, and are laminated while being shifted by a length δx in the X direction orthogonal to the extension direction of one short side 23a. Consequently, each one short side 23a is visible in a state where the separators 23 are laminated.

Description

  The present invention relates to a power storage device and a method for manufacturing an electrode assembly.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery as a power storage device that stores power supplied to the traveling motor. The secondary battery includes, for example, an electrode assembly in which a positive electrode sheet and a negative electrode sheet in which an active material layer is formed on a metal foil are alternately stacked with a separator formed of a resin or the like interposed therebetween ( For example, see Patent Document 1).

JP 2002-343439 A

  Here, in order to confirm a short circuit or the like of each electrode sheet, it may be confirmed whether or not each electrode sheet and separator are misaligned. In this case, in each electrode sheet having a metal foil, misalignment can be easily confirmed by using X-rays, whereas in a separator formed of resin or the like, the position is not reflected in X-rays. It is difficult to confirm the deviation.

  The present invention has been made in view of the above-described circumstances, and provides a power storage device and a method for manufacturing an electrode assembly that can easily confirm the displacement of each separator that constitutes the electrode assembly. Objective.

  In order to achieve the above object, the invention according to claim 1 includes a plurality of rectangular positive electrode sheets, a plurality of rectangular negative electrode sheets, and a plurality of rectangular separators, wherein the positive electrode sheet and the negative electrode sheet include In the power storage device including an electrode assembly configured to be alternately stacked with the separator interposed therebetween, the plurality of positive electrode sheets are stacked so that two adjacent sides overlap each other when viewed from the stacking direction. The plurality of negative electrode sheets are stacked such that two adjacent side portions overlap each other when viewed from the stacking direction, and each protruding portion formed by protruding each separator is provided. The protruding lengths of the protruding portions are sequentially shortened toward one side in the stacking direction.

  According to this invention, since the protrusion length of each protrusion part is shortened sequentially toward one side of the lamination direction, each protrusion part of each separator is arrange | positioned sequentially. Thereby, when each electrode sheet and each separator are stacked, each protruding portion is visible when viewed from the stacking direction. Therefore, the position shift of each separator can be easily confirmed by checking each protrusion part from the lamination direction.

  The invention according to claim 2 is characterized in that the protruding portion is formed so as to protrude in a direction intersecting with a direction in which the one side portion of the separator extends. According to this invention, the protruding portion is formed so as to protrude in the direction intersecting with the extending direction of the one side portion of the separator, so that one side portion of each separator is sequentially shifted in the direction intersecting with the extending direction of the one side portion. . Thereby, one side part of each separator becomes visible when viewed from the stacking direction. Therefore, the position shift of each separator can be easily confirmed by confirming one side of each separator from the stacking direction.

  According to a third aspect of the present invention, the separators have the same shape, and the protruding portions have a predetermined length in a direction intersecting the extending direction of the one side part toward the one side in the stacking direction. It is characterized by being formed by sequentially laminating one by one. According to this invention, each separator has a protrusion length different by a predetermined length by sequentially laminating each separator by a predetermined length in a direction intersecting the extending direction of one side toward one side of the stacking direction. Part is formed, and one side part of the separator becomes visible from the stacking direction. Thereby, the state where each one side part shifted can be realized using a plurality of separators of the same shape.

  In the invention according to claim 4, each protruding portion has a side that is orthogonal to the one side of each separator shortened by a predetermined length toward one side in the stacking direction, and is viewed from the stacking direction. The positions of the opposite sides of the one side portions constituting the protruding portions are made to coincide with each other. According to this invention, by aligning the positions of the opposite sides of the separators, the protruding portions having different protruding lengths by a predetermined length are formed, and one side portion of each separator is shifted and disposed. Thus, when the separators are stacked, the separators can be easily stacked as much as it is not necessary to consider the deviation.

  The invention according to claim 5 is characterized in that each of the protruding portions is curved in the stacking direction. According to this invention, since each protrusion part curves in the lamination direction, the edge part of the protrusion direction of each electrode sheet pinched | interposed into each separator is covered with the aggregate | assembly which consists of each protrusion part. Thereby, when each electrode sheet tries to move in the protruding direction, each electrode sheet and the protruding portion come into contact with each other, and the movement is restricted. Thereby, the position shift of each electrode sheet with respect to a separator is controlled. Therefore, the position shift of each electrode sheet can be suppressed using the configuration relating to the confirmation of the position shift of each separator.

The invention according to claim 6 is characterized in that the power storage device is a secondary battery.
The invention according to claim 7 includes a plurality of rectangular positive electrode sheets, a plurality of rectangular negative electrode sheets, and a plurality of rectangular separators, and the positive electrode sheet and the negative electrode sheet sandwich the separator therebetween. In the method of manufacturing an electrode assembly that is alternately stacked, each positive electrode sheet is stacked so that two adjacent side portions thereof are overlapped when viewed from the stacking direction, and each negative electrode sheet is The separators are stacked such that two adjacent sides overlap each other when viewed from the stacking direction, and the separators are stacked such that one side of each separator is sequentially shifted when viewed from the stacking direction. To do. According to this invention, by separating the separators so that one side of each separator is sequentially displaced, one side of each separator can be visually recognized from the stacking direction, and therefore, by confirming one side of each separator. The position shift of each separator can be easily confirmed.

  According to this invention, it is possible to easily confirm the positional deviation of each separator.

The perspective view of a secondary battery. The exploded perspective view of an electrode assembly. The front view which shows the lamination | stacking aspect of an electrode assembly. Sectional drawing which cut | disconnected the secondary battery along the lamination direction of an electrode assembly. (A)-(e) is a front view for demonstrating the lamination | stacking process of an electrode assembly. (A), (b) is sectional drawing for demonstrating the manufacturing process of an electrode assembly. The perspective view which shows the electrode assembly of another example. (A) is a front view which shows the lamination | stacking aspect of the electrode assembly of another example, (b), (c) is sectional drawing for demonstrating the manufacturing process of the electrode assembly of another example. (A) is the front view and partial enlarged view of another example electrode assembly, (b) is the 1-1 sectional view taken on the line of (a).

  Hereinafter, a power storage device according to the present invention will be described with reference to FIGS. The power storage device is mounted on a vehicle (automobile and industrial vehicle) and is used to drive a traveling motor (electric motor) mounted on the vehicle. For the convenience of the drawings, some configurations such as the shift length δx related to the stacking of the separators 23 are shown different from the actual dimensions.

  As shown in FIG. 1, a secondary battery 10 as a power storage device is a lithium ion secondary battery, and includes a case 11 that forms an outer shell thereof. The case 11 is made of, for example, metal, and includes a rectangular box-shaped container 12 that opens in one direction, and a rectangular flat plate-shaped lid 13 that closes the opening of the container 12. For this reason, the secondary battery 10 has a rectangular outer shape.

  The case 11 accommodates an electrode assembly 14 as a charge / discharge element and an electrolyte solution (not shown) as an electrolyte. As shown in FIG. 2, the electrode assembly 14 includes a porous film (a positive electrode sheet 21 as a positive electrode and a negative electrode sheet 22 as a negative electrode that allow ions related to electric conduction to pass through and are difficult to be reflected in X-rays. For example, the sheet-like separators 23 made of polyethylene resin) are alternately stacked with the sheet-like separators 23 sandwiched therebetween. The separator 23 is also disposed on both end surfaces 14 a and 14 b in the stacking direction of the electrode assembly 14.

  In FIG. 1 and the like, the number of the positive electrode sheets 21 constituting the electrode assembly 14 is five, the number of the negative electrode sheets 22 is six, and the number of separators 23 is twelve. However, the number of stacked sheets is arbitrary. . Incidentally, the negative electrode sheet 22 is laminated one more than the positive electrode sheet 21 so that the negative electrode sheet 22 is arranged on both sides of the positive electrode sheet 21 in the lamination direction of the positive electrode sheet 21 and the negative electrode sheet 22.

  Each positive electrode sheet 21 has the same shape, and each negative electrode sheet 22 has the same shape. In addition, the same shape said in this specification means what permitted some shaping | molding error, for example, what was formed using the same metal mold | die, etc. can be considered.

  As shown in FIG. 2, each of the electrode sheets 21 and 22 is formed in a rectangular shape (in detail, a rectangular shape), and has a similar shape. Specifically, the positive electrode sheet 21 is formed slightly smaller than the negative electrode sheet 22.

  The positive electrode sheet 21 includes a rectangular positive electrode metal foil (for example, an aluminum foil) 31 and a positive electrode active material layer 32 formed by applying a positive electrode active material to both surfaces (sheet surfaces) of the positive electrode metal foil 31. It is configured. The positive electrode active material layer 32 is formed in the whole area | region other than the one part area along one long side part 21b among the sheet | seat surfaces of the positive electrode sheet 21 (positive electrode metal foil 31). The negative electrode sheet 22 is formed by applying a negative electrode active material on both sides of a rectangular negative metal foil (for example, copper foil) 33 that is formed to be slightly larger than the positive metal foil 31 and the negative electrode metal foil 33. And the negative electrode active material layer 34. The negative electrode active material layer 34 is formed on the entire region of the sheet surface of the negative electrode sheet 22 (negative electrode metal foil 33) other than a partial region along one long side portion 22 b, and from the positive electrode active material layer 32. Is also formed large.

  As shown in FIG. 2, the electrode sheets 21 and 22 are sequentially laminated with the centers of the electrode sheets 21 and 22 being aligned via the separator 23. In this case, each positive electrode sheet 21 is laminated in a state where one long side portion 21b and one short side portion 21a adjacent to each other are overlapped as two adjacent side portions, and each negative electrode sheet 22 is respectively stacked. As two adjacent side portions, one long side portion 22b and one short side portion 22a adjacent to the long side portion 22b are stacked. For this reason, as shown in FIG. 3, each positive electrode sheet 21 is disposed at the same position within a predetermined tolerance range when viewed from the stacking direction, and each negative electrode sheet 22 is within the predetermined tolerance range when viewed from the stacking direction. Arranged at the same position.

  Further, in the configuration in which the electrode sheets 21 and 22 are laminated via the separator 23 as described above, the positive electrode active material layer 32 and the negative electrode active material layer 34 face each other with the separator 23 interposed therebetween. Yes.

  As shown in FIG. 1, current collecting tabs 41 and 42 (each tab) projecting from the side surface are provided on the side surface in the direction orthogonal to the stacking direction of the electrode assembly 14. As shown in FIG. 2, the current collecting tabs 41 and 42 are formed by extending the metal foils 31 and 33 from a part of one of the long side portions 21 b and 22 b of the electrode sheets 21 and 22, respectively. ing. The extension dimensions of the current collecting tabs 41 and 42 are set so as to protrude from the separator 23 in a state in which the electrode assembly 14 is configured.

  For the sake of convenience, in this specification, it is assumed that the positive electrode sheet 21 does not include the positive electrode current collecting tab 41 in the present specification. Similarly, it is assumed that the negative electrode sheet 22 does not include the negative electrode current collecting tab 42.

  As shown in FIGS. 1 and 2, the electrode sheets 21 and 22 have the centers of the electrode sheets 21 and 22 coincided with each other, and the same polarities of the current collecting tabs 41 and 42 are arranged in a row in the stacking direction. On the other hand, they are stacked so that different polarities do not overlap in the stacking direction.

  As shown in FIG. 1, the secondary battery 10 includes a positive electrode terminal 51 and a negative electrode terminal 52 for taking out the electric power of the electrode assembly 14. Each of the terminals 51 and 52 is attached in a state of penetrating the case 11, and a part thereof is exposed outside the case 11. The secondary battery 10 includes a positive electrode conductive member 61 and a negative electrode conductive member 62 that electrically connect the same polarities of the terminals 51 and 52 and the current collecting tabs 41 and 42 to each other. Thereby, the electric power of the electrode assembly 14 can be taken out of the case 11 and the electrode assembly 14 can be charged by supplying electric power to the electrode assembly 14.

Here, each separator 23 which comprises the electrode assembly 14 is demonstrated in detail.
As shown in FIG. 2, each of the plurality of separators 23 has the same shape and is formed in a rectangular shape, and includes short side portions 23a and 23c and long side portions 23b and 23d. Each separator 23 is formed in a size capable of covering each electrode sheet 21, 22 (a portion other than each current collecting tab 41, 42). Specifically, the lengths of the short sides 23 a and 23 c of each separator 23 are set longer than the length of one short side 22 a of the negative electrode sheet 22. The lengths of the long side portions 23 b and 23 d of each separator 23 are set to be longer than the length of one long side portion 22 b of the negative electrode sheet 22.

  For convenience of explanation, in the following explanation, the long side direction is the X direction and the short side direction is the Y direction. The Y direction can also be said to be a direction along the protruding direction of the current collecting tabs 41 and 42, and the X direction can also be said to be a direction orthogonal to the direction along the protruding direction of the current collecting tabs 41 and 42.

  Here, the separators 23 are stacked in a state of being sequentially displaced in the X direction while covering the electrode sheets 21 and 22, respectively. Specifically, as shown in FIGS. 2 and 3, each separator 23 has a center line in the Y direction that coincides with a center line in the Y direction of each electrode sheet 21 and 22, and from one end side in the stacking direction. They are laminated in a state of being sequentially shifted by a predetermined shift length δx (for example, 20 μm) toward the other short side 23c toward the other end side (one side). As a result, as shown in FIG. 3, in the state where the electrode sheets 21 and 22 and the separator 23 are stacked, one short side portion 23a as one side portion of each separator 23 when viewed from the other end side in the stacking direction. And the other short side part 23c as one side part has shifted | deviated and arrange | positioned in the X direction. Therefore, when viewed from the other end side in the stacking direction, one short side portion 23a of each separator 23 is visible.

  Here, the length of the separator 23 in the X direction is such that each electrode sheet 21 and 22 can be entirely covered even when the separators 23 are sequentially stacked by the shift length δx. It is set corresponding to the shift length δx and the number of stacked separators 23. Specifically, the length of the separator 23 in the X direction is set longer than the length of the negative electrode sheet 22 in the X direction plus (shift length δx) × (number of stacked separators 23). ing. Thus, in the configuration in which the separators 23 are sequentially stacked with a shift length δx, the electrode sheets 21 and 22 are covered with the separators 23.

  As shown in FIG. 3, since the length of the separator 23 in the X direction is longer than the length of the negative electrode sheet 22 in the X direction, the electrode sheets 21 and 22 and the separator 23 are sequentially laminated as described above. A part of each separator 23 protrudes (extends) in the X direction from each short side portion 22 a, 22 c of the negative electrode sheet 22. The protruding portion on the one short side portion 23a side that protrudes from one short side portion 22a is protruded from the first protruding portion 71 and the other short side portion 22c, and the protruding portion on the other short side portion 23c side is the second. The protruding portion 72 is used. The first protruding portions 71 and the second protruding portions 72 are disposed on both sides in the X direction with respect to the electrode sheets 21 and 22. In other words, the electrode assembly 14 is provided with the first protruding portion 71 and the second protruding portion 72 formed by protruding each separator 23 from the negative electrode sheet 22 in the X direction.

  Since each separator 23 is gradually shifted in the X direction and stacked, the extension dimension (extraction length) of each first protrusion 71 from the negative electrode sheet 22 and the extension dimension of each second protrusion 72 are as follows: Each separator 23 is different. Specifically, as shown in FIG. 4, the extension dimension of each first protruding portion 71 is from one end side in the stacking direction, specifically from the bottom side of the container 12 to the other end side in the stacking direction. Is gradually shortened by a shift length (predetermined length) δx toward the one on the lid 13 side. On the contrary, the extension dimension of each second protruding portion 72 is sequentially shortened by a shift length δx from the other end side in the stacking direction toward the one end side. The extension dimension (protrusion length) of the first protrusion 71 is the maximum on one end side in the stacking direction, and is δx × (m−1), where m is the number of separators 23 stacked. Further, the extension dimension (projection length) of the second projecting portion 72 is the maximum on the other end side in the stacking direction, and is δx × (m−1). Further, the center of the separator 23 in the vicinity of the center of the electrode assembly 14 in the stacking direction is arranged so as to approach the center of each of the electrode sheets 21 and 22. In the present embodiment, as shown in FIG. 4, since the number of separators 23 is an even number, the sixth separators 231 and 232 from the one end and the other end in the stacking direction are the centers of the electrode sheets 21 and 22, respectively. To be closest.

  As shown in FIG. 4, each 1st protrusion part 71 is curving toward the other end side in the lamination direction. For this reason, the aggregate | assembly which consists of each 1st protrusion part 71 has covered one short side part 21a, 22a of each electrode sheet 21 and 22 in the curved state.

  Further, each first protruding portion 71 is configured such that its end portion, specifically, one short side portion 23a does not protrude from the end surface 14b on the lid 13 side in the stacking direction of the electrode assembly 14. Specifically, the shift length δx is set so that each short side portion 23a does not protrude from the end surface 14b on the lid 13 side in the stacking direction of the electrode assembly 14 when each first protrusion 71 is curved. It is set corresponding to the thickness of each electrode sheet 21, 22 and separator 23. Specifically, the shift length δx is the same as or equal to the dimension obtained by combining the thickness of one of the negative electrode sheet 22 or the positive electrode sheet 21 or the average thickness of the electrode sheets 21 and 22 and the thickness of the separator 23. Is set shorter. Thereby, each 1st protrusion part 71 is settled in the range from the one end of the lamination direction in the electrode assembly 14 to the other end.

  The second protruding portion 72 has the same configuration as that of the first protruding portion 71 except that the second protruding portion 72 is bent in the direction opposite to the bending direction of the first protruding portion 71, and detailed description thereof will be given. Omitted.

  Incidentally, as already described, the current collecting tabs 41 and 42 are provided on one of the long side portions 21b and 22b of the electrode sheets 21 and 22 (see FIG. 3). For this reason, each current collection tab 41 and 42 and the short side parts 23a and 23c of each separator 23 do not overlap.

Next, the manufacturing method of the electrode assembly 14 of this embodiment is demonstrated using FIG.
First, as shown in FIG. 5A, using a suction device or the like, the separator 23 is taken out from a magazine in which a plurality of separators 23 are stored, and the separator 23 is temporarily installed in a temporary installation work space S1 in which a stacking target is temporarily installed. Install in. Then, the separator 23 is installed in the stacking work space S2. In this case, the reference position P is such that the centers of the separators 231 and 232 near the center in the stacking direction of the electrode assembly 14 are close to the reference position P where the centers of the electrode sheets 21 and 22 are arranged in the stacking work space S2. The separator 23 is disposed at a position shifted by a specific length on one side (one short side 23a side) in the X direction relative to P. The specific length is δx × (m−1) / 2, which is half of the maximum value of the extension dimension of the first protruding portion 71, and varies depending on the number of stacked separators 23.

  Note that a specific mode of alignment is arbitrary. For example, the separator 23 is installed according to the reference position of the temporary installation workspace S1. Next, the center of the separator 23 may be shifted from the reference position P of the stacking work space S2 to one side in the X direction by a specific length corresponding to the number of stacked sheets.

  Further, for example, when the separator 23 is installed in the temporary installation workspace S1, the center of the separator 23 is shifted from the reference position of the temporary installation workspace S1 on one side in the X direction by a specific length according to the number of stacked layers, Next, it is good also as an aspect installed in the reference | standard position P of the workspace S2 for lamination | stacking, maintaining the state shifted | deviated. At this time, the reference position of the temporary installation work space S1 and the reference position P of the stacking work space S2 are reference points having the same coordinates.

  Thereafter, as shown in FIG. 5B, the negative electrode sheet 22 is taken out from a magazine in which a plurality of negative electrode sheets 22 are accommodated, and the negative electrode sheet 22 is installed in the temporary installation workspace S1. Then, the negative electrode sheet 22 is installed so that the reference position P of the stacking work space S2 coincides with the center of the negative electrode sheet 22. Through this step, the negative electrode sheet 22 is placed on the separator 23.

  Then, as shown in FIG. 5C, another separator 23 is installed. In this case, the separator 23 is arranged at a position shifted from the separator 23 previously installed by the shift length δx toward the other short side 23c.

  The position of the separator 23 installed last time may be grasped using a camera or the like, or the coordinate information of the separator 23 may be stored when the previous separator 23 is installed. .

  Thereafter, as shown in FIG. 5D, the positive electrode sheet 21 is taken out from a magazine in which a plurality of positive electrode sheets 21 are accommodated, and the positive electrode sheet 21 is installed in the temporary installation work space S1. And the positive electrode sheet 21 is installed so that the center of the negative electrode sheet 22 installed last time and the center of the positive electrode sheet 21 may correspond. Specifically, for example, the center coordinates of the negative electrode sheet 22 installed last time are stored, and the positive electrode sheet 21 is installed such that the center coordinates coincide with the central coordinates of the positive electrode sheet 21 installed this time. However, the present invention is not limited to this, and the positive electrode sheet 21 may be installed such that the reference position P of the stacking work space S2 is aligned with the center of the positive electrode sheet 21.

Then, as shown in FIG. 5E, the next separator 23 is installed at a position shifted from the previous separator 23 by the shift length δx toward the other short side 23c.
The electrode sheets 21 and 22 and the separator 23 are stacked by repeatedly executing the above steps. As a result, as shown in FIG. 6A, the electrode assembly 14 is formed in which the short sides 23a and 23c of each separator 23 are stacked while being shifted in the X direction. In addition, since each positive electrode sheet | seat 21 is laminated | stacked in the state where each was the same shape and the center corresponded, one adjacent short side part 21a and one long side part 21b have overlapped (refer FIG. 3). . The same applies to each negative electrode sheet 22.

  In addition, although illustration is abbreviate | omitted, the holding apparatus which hold | grips the laminated body installed in the workspace S2 for lamination | stacking is provided. The gripping device releases the gripping of the stacked body when the electrode sheets 21 and 22 and the separator 23 are installed in the stacking work space S2 while gripping the stacked body installed in the stacking work space S2. . Thereby, position shift of each electrode sheet 21 and 22 and separator 23 during lamination is regulated.

  After the lamination of the electrode sheets 21 and 22 and the separator 23 is completed, it is checked (inspected) whether there is any abnormality in the lamination mode of the electrode sheets 21 and 22 and the separator 23. Specifically, it is confirmed using X-rays whether or not the positional deviation between the electrode sheets 21 and 22 has occurred. Further, the electrode assembly 14 is observed from the stacking direction using a camera or the like, and it is confirmed whether or not the deviation of the short side portions 23a and 23c as one side portion of each separator 23 is normal.

  When there is no abnormality in the stacking mode, each first protruding portion 71 is bent toward the other end in the stacking direction, and each second protruding portion 72 is bent in a direction opposite to the bending direction of each first protruding portion 71. Bend to one end. Accordingly, as shown in FIG. 6B, each first protruding portion 71 and each second protruding portion 72 are curved within a range from one end to the other end in the stacking direction of the electrode assembly 14. Then, the electrode assembly 14 to which the conductive members 61 and 62 are attached is inserted into the container 12 from the stacking direction of the electrode assembly 14 through the opening of the container 12, and then the opening of the container 12 is closed with the lid 13. Then, the terminals 51 and 52 are attached, and the terminals 51 and 52 and the conductive members 61 and 62 are welded.

Next, the effect | action of the secondary battery 10 of this embodiment is demonstrated.
As already described, since each separator 23 is sequentially laminated in the X direction by a predetermined deviation length δx from one end side to the other end side in the lamination direction, each electrode sheet 21, 22 and separator 23 is In the stacked state, one short side portion 23a (and the other short side portion 23c) of each separator 23 is visible when viewed from the stacking direction. Thereby, the position shift of each separator 23 can be confirmed easily.

  Specifically, if the number of the short side portions 23a that can be visually recognized is different from the number of stacked separators 23, the separators 23 are erroneously stacked or the electrode sheets 21 and 22 are stacked. There is a probability that the separator 23 is not stacked between the two. Even when the numbers are the same, if the interval in the X direction of each one of the short side portions 23a is outside the allowable range, each electrode sheet 21 is caused by the displacement of the separator 23. , 22 are short-circuited.

  Furthermore, as shown in FIG. 3, since each one short side part 23a has shifted | deviated to the X direction, some long side parts 23b and 23d of each separator 23 are visually recognizable. Thereby, by visually recognizing each long side part 23b, 23d, the shift | offset | difference of the Y direction of each separator 23 and the rotation shift | offset | difference of each separator 23 can be confirmed.

  Moreover, the 1st protrusion part 71 and the 2nd protrusion part 72 are accommodated in the case 11 in the state curved in the lamination direction. In this case, since each end part (each short side part 21a, 21c, 22a, 22c) of each electrode sheet 21 and 22 is covered with the aggregate | assembly of each protrusion part 71,72, each electrode sheet 21 , 22 are restricted from moving in the X direction. Thereby, the position shift of each electrode sheet 21 and 22 is regulated.

  When the electrode sheets 21 and 22 and the separator 23 are stacked, when viewed from the other end side in the stacking direction, one short side portion 23a is visually recognized, and when viewed from one end side in the stacking direction. The other short side 23c on the side opposite to the one short side 23a is visually recognized. In such a configuration, when confirming the displacement of each separator 23, both may be confirmed, or only one of them may be confirmed.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) Each positive electrode sheet 21 is laminated by overlapping one short side portion 21a and one long side portion 21b as two adjacent side portions, and each negative electrode sheet 22 has two adjacent side portions. The one short side portion 22a and the one long side portion 22b are stacked so as to overlap each other. In such a configuration, the separators 23 are stacked such that one short side portion 23a of each separator 23 is sequentially shifted by a shift length δx along a direction intersecting the extending direction of the one short side portion 23a. . Specifically, the first protruding portion 71 formed by protruding a part of each separator 23 from the negative electrode sheet 22 in a direction intersecting with the direction in which one short side portion 23a of the separator 23 extends is provided. Then, the extension dimension (protrusion length) of each first protrusion 71 is set to be shorter by one shift length δx in the stacking direction, specifically from one end side to the other end side in the stacking direction. . Thereby, in the state where each electrode sheet 21 and 22 and each separator 23 were laminated, one short side part 23a (and the other short side part 23c) of each separator 23 became visible from the lamination direction. Thereby, by confirming each one short side part 23a using a camera etc., it is possible to confirm whether or not there is an abnormality in the stacking mode of each separator 23, in detail, the positional deviation of each separator 23. . Therefore, it is possible to easily check the positional deviation of each separator 23.

  In particular, in the stacking process of the electrode sheets 21 and 22 and the separator 23, when the stack 23 is installed in the stacking work space S2, when the stacked body is gripped by the gripping device, when the gripping is released, the separator 23 or the like Misalignment can occur. In particular, when the stacking speed is increased in order to shorten the stacking time, the above-mentioned positional deviation is likely to occur. In this case, for each of the electrode sheets 21 and 22, it is possible to easily confirm the positional deviation by X-ray inspection from the stacking direction, but for each separator 23 formed of a resin that does not appear in X-rays The confirmation is likely to be difficult.

  On the other hand, according to the present embodiment, the positional deviation of each separator 23 can be easily found through checking each one of the short sides 23a. Moreover, since each one short side part 23a is visible, the position shift of the separator 23 can be confirmed in real time while the separators 23 are stacked. Thereby, the position shift of each separator 23 can be confirmed more suitably.

  (2) Each separator 23 is formed in the same shape, and each separator 23 is displaced in the direction intersecting with the extending direction (Y direction) of one short side portion 23a (specifically, the displacement length δx in the X direction). It was set as the structure laminated | stacked by shifting. Thereby, each 1st protrusion part 71 from which an extension dimension differs by every shift length (delta) x is formed using each separator 23 of the same shape. Therefore, one short side part 23a of each separator 23 can be made visible.

  (3) In particular, by arranging the separators 23 so as to be stacked in a direction perpendicular to the direction in which the one short side portion 23a extends, the one short side portion 23a of each separator 23 is shifted and arranged. On the other hand, the long side portions 23b and 23d of the separators 23 are overlapped with each other. Thereby, it can suppress that the protrusion part which does not contribute to charging / discharging in the both ends side of the Y direction in the electrode assembly 14 can be suppressed, and the complexity etc. which bend an protrusion part can be avoided.

  (4) The current collecting tabs 41 and 42 are provided on each of the long side portions 21b and 22b which are the ends in the Y direction of the electrode sheets 21 and 22, respectively. In other words, each separator 23 was laminated so that a side portion (one short side portion 23a) different from the long side portion 23b on the side where the current collecting tabs 41 and 42 are formed is shifted. Thereby, it is avoided that each one short side part 23a and each current collection tab 41 and 42 overlap. Therefore, the current collecting tabs 41 and 42 are unlikely to get in the way when confirming each one of the short sides 23a. Furthermore, it is possible to simplify the configuration as long as it is not necessary to lengthen the current collecting tabs 41 and 42 so as to protrude outward from each one short side portion 23a.

  (5) The protrusions 71 and 72 are curved in the stacking direction. Thereby, the area which each protrusion part 71,72 occupies in case 11 is small. Therefore, it is possible to reduce the expansion of the region that does not contribute to charging / discharging due to the formation of the protruding portions 71 and 72.

  In addition, as the protruding portions 71 and 72 are curved in the stacking direction, the end portions (the short side portions 21 a, 21 c, 22 a, and 22 c) of the electrode sheets 21 and 22 are protruded from the protruding portions 71 and 72. It is covered by an aggregate. Thereby, the position shift to the X direction of each electrode sheet 21 and 22 can be suppressed. Therefore, the position shift of each electrode sheet 21, 22 with respect to each separator 23 can be suppressed using a configuration for easily confirming the position shift of each separator 23.

  Furthermore, since the end portions in the X direction of the electrode sheets 21 and 22 are covered with the protruding portions 71 and 72, the X direction in which the protruding portions 71 and 72 are provided exceeds the separator 23. The situation where the positive electrode sheet 21 and the negative electrode sheet 22 come into contact with each other is unlikely to occur. The contact between the end portions of the electrode sheets 21 and 22 in the X direction and the case 11 is restricted. Therefore, these short circuits can be suppressed.

  (6) In a state in which each first protruding portion 71 is curved, each one short side portion 23a which is a tip portion of each first protruding portion 71 is connected from one end to the other end in the stacking direction of the electrode assembly 14 It was configured to be installed within the range. Thereby, each one short side part 23a does not protrude from the end surface 14b on the lid 13 side in the stacking direction of the electrode assembly 14. Therefore, when the electrode assembly 14 is accommodated in the case 11, each one of the short side portions 23a is unlikely to get in the way. Therefore, inconveniences that may be caused by providing a configuration for confirming the displacement of each separator 23 can be avoided.

In addition, you may change the said embodiment as follows.
In the embodiment, each separator 23 has the same shape, but is not limited thereto. For example, as shown in FIGS. 7 and 8, an electrode assembly 80 formed by sequentially laminating a plurality of separators 81 having different lengths in the X direction may be employed.

  Specifically, as shown in FIGS. 7 and 8, each of the separators 81 formed in a rectangular shape is one of one short side 81a and one long side 81b as two adjacent sides. The length of the long side portion 81b of the separator 81, specifically, the length of the separator 81 in the X direction (long side direction) is different by the shift length δx. Each separator 81 has a length in the X direction so that the length of one long side portion 81b gradually decreases in a state where one adjacent short side portion 81a and one long side portion 81b are aligned. Laminated from the longest one. That is, the length of each one long side part 81b orthogonal to each one short side part 81a is gradually shortened from one end side to the other end side in the stacking direction. Accordingly, as shown in FIG. 8A, the other short side portion 81c as one side portion on the side opposite to the one short side portion 81a in each separator 81 is visible from the stacking direction.

  Further, as shown in FIG. 8B, on the other short side portion 81c side in the X direction of the electrode assembly 80, each protruding portion 82 protruding from each separator 81 is formed, whereas each separator 81 One short side portion 81a is aligned. In other words, each short side portion 81a that is the opposite side of each other short side portion 81c that constitutes each protruding portion 82 has the same position when viewed from the stacking direction. Thereby, compared with the separator 23 of embodiment, the length of the X direction of the separator 81 can be shortened, and the cost reduction of the separator 23 can be aimed at through this.

  Furthermore, since each protrusion 82 is formed only on one side of the electrode assembly 80 in the X direction, the electrode assembly 80 is downsized. Specifically, the length of the electrode assembly 80 in the X direction is shortened. The length of the container 83 in the X direction is shorter by the amount of the second protruding portion 72 than the container 12 of the above-described embodiment. Thereby, size reduction of a secondary battery can be achieved.

  In addition, it may replace with size reduction and you may use the accommodation space of the 2nd protrusion part 72 as an area | region which contributes to charging / discharging. Specifically, the length of each electrode sheet 21, 22 in the X direction may be increased by the amount of the accommodation space of the second protrusion 72. Thereby, the area | region which contributes to charging / discharging can be aimed at.

  In addition, when viewed from the other end side in the stacking direction, the stacking mode is sequentially stacked from the one having the short length in the X direction so that the length of each one long side portion 81b is gradually increased. It can be said that it is.

  In addition, in the configuration in which one short side portion 81 a of each separator 81 is aligned, an insulating sheet is provided between the side surface of the electrode assembly 14 formed by each one short side portion 81 a and the inner surface of the case 11. It may be provided separately.

  In the above configuration, for example, as illustrated in FIG. 8B, the protruding portions 82 may be accommodated in the container 83 in advance without being curved. In this case, as shown in FIG. 8C, the protruding portions 82 are naturally bent in the stacking direction by contact with the inner surface of the container 83. Thereby, simplification of a process can be achieved.

  Further, as shown in FIGS. 9 (a) and 9 (b), an electrode assembly 90 in which a plurality of separators 91 each having a similar shape are stacked in order from the largest is adopted. Good. Specifically, each separator 91 is formed in a rectangular shape, and the two adjacent side portions are formed with different lengths. And each separator 91 is laminated | stacked in an order from the big thing in the state in which the center has corresponded. For this reason, the electrode assembly 90 has a pyramid shape as a whole, and the entire peripheral edge of each separator 91 is visible when viewed from the stacking direction.

  In addition, in the structure using the some separator 91 which each made the similar shape, it is not restricted to the aspect laminated | stacked by making a center correspond, For example, it is good also as an aspect laminated | stacked by making one corner part correspond.

  In the embodiment, the shift length δx is a constant length, but is not limited thereto, and may be configured to be different. Specifically, the displacement length δx may be configured to be longer than others in a region where the displacement is likely to occur, for example, in the vicinity of the central portion of the electrode assembly 14 in the stacking direction.

  The deviation length δx may be set as appropriate in relation to a pitch or the like that can be grasped (viewed) when confirming the positional deviation. For example, the shift length δx may be set shorter than the thickness of each electrode sheet 21, 22. In this case, the region occupied by the first protrusions 71 in the X direction can be reduced by suppressing the overlap between the first protrusions 71.

  On the contrary, each electrode has a deviation length δx within a range that does not protrude from the end surface 14b on the lid 13 side in the stacking direction of the electrode assembly 14 when each first protruding portion 71 is bent in the stacking direction. It may be set longer than the thickness of the sheets 21 and 22.

  Further, when each first protruding portion 71 is bent in the stacking direction, a part of the first protruding portion 71 is allowed to protrude from the end surface 14b on the lid 13 side in the stacking direction of the electrode assembly 14, and the shift length δx is increased. It may be set. In this case, the position shift of each separator 23 can be easily confirmed.

  In the embodiment, each separator 23 is configured to shift in the X direction. However, the present invention is not limited thereto, and at least one of the long side portions 23b and 23d may be shifted to the Y direction as one side portion. Thereby, the long side parts 23b and 23d of each separator 23 become visible. In this case, the extension dimensions of the current collecting tabs 41 and 42 may be set (longer) so as to protrude from the separators 23.

  Moreover, it is good also as a structure which laminates | stacks each separator 23 shifting to both X direction and Y direction. In this case, when viewed from the stacking direction, one short side 23a and one long side 23b (the other short side 23c and the other long side 23d) as the two adjacent sides of each separator 23 are visible. It becomes possible.

  In the embodiment, the electrode sheets 21 and 22 have been laminated so that their centers coincide with each other. However, the present invention is not limited to this. For example, the corners may be laminated with each other. Any one of the long side portions 21b and 22b of the electrode sheets 21 and 22 may be made to coincide with each other.

  In the embodiment, the electrode assembly 14 is housed in the container 12 in a state where the protruding portions 71 and 72 are curved. However, the present invention is not limited to this, and the electrode assembly 14 and the electrode assembly 14 are not curved. It is good also as a structure which accommodates the solid 14 in the container 12. FIG.

  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.

In the embodiment, the secondary battery 10 is mounted on the vehicle, but is not limited thereto, and may be mounted on another device.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

(B) The power storage device according to claim 3, wherein the separators are stacked sequentially shifted in a direction orthogonal to a direction in which the one side extends.
(B) having a plurality of rectangular positive sheets, a plurality of rectangular negative sheets, and a plurality of rectangular separators, and the positive sheets and the negative sheets are stacked with the separators sandwiched therebetween In the power storage device including the electrode assembly, the plurality of positive electrode sheets are stacked such that two adjacent side portions overlap each other when viewed from the stacking direction, and the plurality of negative electrode sheets are stacked from the stacking direction. The separators are stacked such that two adjacent side portions overlap each other, and each separator covers the positive electrode sheet and the negative electrode sheet, and the one side portion extends along a direction intersecting with the extending direction of the one side portion. A power storage device, wherein the power storage devices are stacked so as to be sequentially shifted by a predetermined length.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 11 ... Case, 12 ... Container, 14 ... Electrode assembly, 21 ... Positive electrode sheet, 22 ... Negative electrode sheet, 23 ... Separator, 23a, 23c ... Short side part of separator, 23b, 23d: long side portion of the separator, 71: first protruding portion, 72: second protruding portion, 81, 91: another example separator.

Claims (7)

A plurality of rectangular positive electrode sheets, a plurality of rectangular negative electrode sheets, and a plurality of rectangular separators, and the positive electrode sheets and the negative electrode sheets are alternately stacked with the separators interposed therebetween. In a power storage device provided with an electrode assembly,
The plurality of positive electrode sheets are laminated so that two adjacent sides overlap each other when viewed from the lamination direction,
The plurality of negative electrode sheets are laminated so that two adjacent sides overlap each other when viewed from the lamination direction,
Each protruding portion formed by protruding each separator is provided,
The protruding length of each protruding portion is sequentially shortened toward one side in the stacking direction.   The power storage device according to claim 1, wherein the protruding portion is formed so that the separator protrudes in a direction intersecting with a direction in which one side portion of the separator extends. Each of the separators has the same shape,
Each of the protruding portions is formed by sequentially laminating each of the separators by a predetermined length in a direction intersecting the extending direction of the one side toward one side of the stacking direction. The power storage device according to claim 2.   Each protruding portion has a side that is orthogonal to the one side of each separator shortened by a predetermined length toward one side in the stacking direction, and configures each protruding portion when viewed from the stacking direction. The power storage device according to claim 2, wherein the positions of the opposite sides of each one side are matched.   5. The power storage device according to claim 1, wherein each of the protruding portions is curved in the stacking direction.   The power storage device according to claim 1, wherein the power storage device is a secondary battery. It has a plurality of rectangular positive electrodes, a plurality of rectangular negative sheets, and a plurality of rectangular separators, and the positive sheets and the negative sheets are alternately stacked with the separators in between. In the manufacturing method of the electrode assembly,
Each of the positive electrode sheets is laminated so that two adjacent sides overlap each other when viewed from the lamination direction,
Each of the negative electrode sheets is laminated so that the two adjacent sides overlap each other when viewed from the lamination direction,
The method of manufacturing an electrode assembly, wherein the separators are stacked such that one side of each separator is sequentially shifted when viewed from the stacking direction.