JP2022030155A - Power storage device - Google Patents

Abstract

To suppress impregnation nonuniformity of an electrolyte.SOLUTION: A spacer 50 is disposed between a positive electrode collector 32 and a negative electrode collector which are adjacent to each other in a lamination direction Z. The positive electrode collector 32 and the negative electrode collector which are adjacent to each other in the lamination direction Z define and form a space together with the spacer 50. The spacer 50 is formed in a rectangular frame shape in a planar view in the lamination direction Z and comprises a first edge part 51, a second edge part 52 and a third edge part 53. The spacer 50 comprises an opening 60 extending from the space to the outside of the space. The opening 60 includes a first opening part 61, a second opening part 62 and a third opening part 63. The first opening part 61 penetrates the first edge part 51 in a first direction X. The second opening part 62 penetrates the second edge part 52 in a second direction Y. The third opening part 63 penetrates the third edge part 53 in the first direction X.SELECTED DRAWING: Figure 3

Description

The present invention relates to a power storage device.

As a power storage device, a current collector having a plurality of stacked current collectors, a positive electrode active material layer, a negative electrode active material layer, and a spacer is known. The positive electrode active material layer is arranged on one surface of the current collector in the stacking direction of the current collector. The negative electrode active material layer is arranged on the other surface of the current collector in the stacking direction. The spacer is arranged between two current collectors adjacent to each other in the stacking direction, and surrounds the positive electrode active material layer and the negative electrode active material layer. A space is partitioned inside the power storage device by two current collectors and spacers that are adjacent to each other in the stacking direction. This space is filled with an electrolytic solution.

Further, in the power storage device described in Patent Document 1, a pair of openings facing each other are formed in the spacer so as to sandwich the internal space of the power storage device in which the electrode active material layer is arranged. By immersing one opening in the electrolytic solution and sucking up the electrolytic solution from the other opening, the electrode active material layer arranged in the internal space is impregnated with the electrolytic solution.

Japanese Unexamined Patent Publication No. 2007-95653

By the way, in the power storage device described in Patent Document 1, the flow of the electrolytic solution in the internal space generated when the electrolytic solution is impregnated is dominated by a linear flow in one direction from one opening to the other opening. It becomes. Therefore, in the space inside the power storage device, the electrolytic solution does not sufficiently reach the end of the electrode active material layer in the direction intersecting the flow direction of the electrolytic solution, and the electrode active material layer is impregnated with the electrolytic solution unevenly. May occur. Occurrence of uneven impregnation of the electrolytic solution is not preferable because it may lead to deterioration of battery performance in the power storage device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a power storage device capable of suppressing uneven impregnation of an electrolytic solution.

The power storage device that solves the above problems includes a current collector that is laminated in the stacking direction, a positive electrode active material layer that is arranged on the first surface that is one surface of the current collector in the stacking direction, and a positive electrode active material layer that is arranged in the stacking direction. The negative electrode active material layer arranged on the second surface which is the other surface of the current collector and the positive electrode active material layer and the negative electrode are arranged between the two adjacent current collectors in the stacking direction. A power storage device including a spacer surrounding the active material layer, wherein the spacer has a square frame shape in a plan view seen from the stacking direction, and has a positive electrode active material layer and a negative electrode active material layer. , A first edge portion arranged on one side in the first direction intersecting the stacking direction, and a second edge portion arranged on one side in the second direction intersecting both the stacking direction and the first direction. An opening extending outward from the space formed by the third edge portion facing the first edge portion in the first direction and the two adjacent current collectors and spacers adjacent to each other in the stacking direction. The opening comprises a first opening penetrating the first edge along the first direction and a second opening penetrating the second edge along the second direction. It is characterized by comprising a portion and a third opening that penetrates the third edge portion along the first direction.

According to the above configuration, a part of the first opening, the second opening, and the third opening is used as an injection port for injecting the electrolytic solution into the space inside the power storage device, and the others. By using the opening of the above as a discharge port for discharging the electrolytic solution from the space, the positive electrode active material layer and the negative electrode active material layer can be impregnated with the electrolytic solution. Each of the first opening, the second opening, and the third opening is arranged at different edges of the spacer. By injecting the electrolytic solution into the space through the injection port while discharging the electrolytic solution from the discharge port, the electrolytic solution can flow into the space near the three edges of the spacer. Immediately after flowing into the space from the injection port, the electrolytic solution flows along the penetrating direction of the opening used as the injection port to the spacer. The electrolytic solution immediately before reaching the discharge port flows along the penetrating direction of the opening used as the discharge port to the spacer. The first direction and the second direction intersect each other. Therefore, the electrolytic solution reaches the ends of the positive electrode active material layer and the negative electrode active material layer in the direction intersecting the inflow direction of the electrolytic solution. Therefore, uneven impregnation of the electrolytic solution can be suppressed.

In the power storage device, the first opening is an injection port for injecting the electrolytic solution into the space, and the second opening and the third opening are for discharging the electrolytic solution from the space. It is preferably an outlet.

According to the above configuration, the electrolytic solution flows from the first opening toward the second opening and the third opening, so that the electrolytic solution can flow toward the second edge and the third edge. Here, the first edge portion is arranged on one side in the first direction with respect to the positive electrode active material layer and the negative electrode active material layer. The second edge portion is arranged on one side in the second direction with respect to the positive electrode active material layer and the negative electrode active material layer. Therefore, the flow of the electrolytic solution from the first opening to the second opening is from the first edge to the second edge. By this flow of the electrolytic solution, the electrolytic solution can be impregnated at the ends of the positive electrode active material layer and the negative electrode active material layer in the direction intersecting the inflow direction of the electrolytic solution. On the other hand, the third edge portion faces the first edge portion in the first direction. Therefore, the flow of the electrolytic solution from the first opening to the third opening is a linear flow from the first edge to the third edge. The linear flow of the electrolytic solution allows the electrolytic solution to be impregnated at the ends of the positive electrode active material layer and the negative electrode active material layer in the inflow direction of the electrolytic solution. Therefore, each end of the positive electrode active material layer and the negative electrode active material layer in the direction intersecting the inflow direction of the electrolytic solution, and the end of the positive electrode active material layer and the negative electrode active material layer in the inflow direction of the electrolytic solution. Since the electrolytic solution can be impregnated into the water, uneven impregnation of the electrolytic solution can be further suppressed.

In the power storage device, the first opening is an injection port for injecting the electrolytic solution into the space, and the third opening is a discharge port for discharging the electrolytic solution from the space. It is preferable that the first opening and the third opening face each other in the first direction.

According to the above configuration, the path of the electrolytic solution flowing from the first opening to the third opening is shorter than that in the case where the first opening and the third opening do not face each other in the first direction. Therefore, since the time required for the electrolytic solution to reach the first opening to the third opening can be shortened, the working time for impregnating the electrolytic solution can be shortened.

In the power storage device, the first opening is an injection port for injecting the electrolytic solution into the space, and the second opening is a discharge port for discharging the electrolytic solution from the space. It is preferable that the second opening is arranged at a position of the second edge portion closer to the connection end portion with the third edge portion than the connection end portion with the first edge portion.

According to the above configuration, the electrolytic solution flowing from the first opening to the second opening flows through the space portion near the third edge. Therefore, as compared with the case where the second opening is arranged at a position closer to the connection end with the first edge than the connection end with the third edge in the second edge, the first direction In, the range of the space through which the electrolytic solution flows can be increased. Therefore, uneven impregnation of the electrolytic solution can be further suppressed.

In the power storage device, the spacer may include a fourth edge portion facing the second edge portion in the second direction, and the opening portion may include a fourth opening portion arranged in the fourth edge portion. preferable.

According to the above configuration, of the first opening, the second opening, the third opening, and the fourth opening, some of the openings are used as injection ports, and the other openings are used as discharge ports. Thereby, the positive electrode active material layer and the negative electrode active material layer can be impregnated with the electrolytic solution. Each of the first opening, the second opening, the third opening, and the fourth opening is arranged at different edges of the spacer. By flowing the electrolytic solution from the injection port toward the discharge port, the electrolytic solution can flow into the space near the four edges of the spacer. Therefore, the impregnation unevenness of the electrolytic solution can be further suppressed as compared with the case where the openings are arranged only at the three edges of the spacer.

In the power storage device, the first opening is an injection port for injecting the electrolytic solution into the space, and the second opening and the fourth opening are for discharging the electrolytic solution from the space. It is preferably an outlet.

According to the above configuration, the electrolytic solution flows from the first opening toward the second opening and the fourth opening, so that the electrolytic solution can flow toward the second edge and the fourth edge. Here, the second edge portion is arranged on one side in the second direction with respect to the positive electrode active material layer and the negative electrode active material layer. The fourth edge portion faces the second edge portion in the second direction. Therefore, as the electrolytic solution flows from the first opening to the second opening and the fourth opening, the electrolytic solution is applied to both ends of the positive electrode active material layer and the negative electrode active material layer in the direction intersecting the inflow direction of the electrolytic solution. Can be impregnated. Therefore, uneven impregnation of the electrolytic solution can be further suppressed.

In the power storage device, it is preferable that the second opening and the fourth opening face each other in the second direction.
If the second opening and the fourth opening do not face each other in the second direction, the path of the electrolytic solution flowing from the first opening to the second opening and the path from the first opening to the fourth opening The path length differs depending on the path of the electrolytic solution flowing toward. When the electrolytic solution is injected from the first opening while discharging the electrolytic solution from both the second opening and the fourth opening, a large amount of the electrolytic solution flows in a short path, so that the second edge and the second edge The electrolytic solution is unevenly flowed into the space near any of the fourth edges. By shifting the timing of discharging the electrolytic solution between the second opening and the fourth opening, it is possible to avoid unevenness in the amount of the electrolytic solution due to the path difference. However, in order to shorten the working time related to the impregnation of the electrolytic solution, it is preferable to impregnate the electrolytic solution while discharging the electrolytic solution from both the second opening and the fourth opening.

According to the above configuration, the second opening and the fourth opening face each other in the second direction. Therefore, the path of the electrolytic solution flowing from the first opening to the second opening and the path of the electrolytic solution flowing from the first opening to the fourth opening have the same path length. Therefore, since the electrolytic solution can be impregnated while discharging the electrolytic solution from both the second opening and the fourth opening, the working time related to the impregnation of the electrolytic solution can be shortened.

In the power storage device, the first opening is an injection port for injecting the electrolytic solution into the space, and the fourth opening is a discharge port for discharging the electrolytic solution from the space. It is preferable that the fourth opening is arranged at a position of the fourth edge portion closer to the connection end portion with the third edge portion than the connection end portion with the first edge portion.

According to the above configuration, the electrolytic solution flowing from the first opening to the fourth opening flows through the space portion near the third edge. Therefore, as compared with the case where the fourth opening is arranged at a position closer to the connection end with the first edge of the fourth edge than with the connection end with the third edge, the first direction Since the range of the space through which the electrolytic solution flows can be increased, the impregnation unevenness of the electrolytic solution can be further suppressed.

According to the present invention, uneven impregnation of the electrolytic solution can be suppressed.

Sectional drawing which shows the power storage device. The cross-sectional view which shows the storage cell in the state before forming a cell stack. FIG. 3 is a sectional perspective view showing a storage cell. Sectional drawing which shows the spacer and the opening. The cross-sectional view for demonstrating the case where the injection of the electrolytic solution into a space is performed using a 1st opening and a 3rd opening. FIG. 3 is a cross-sectional view for explaining a case where injection of an electrolytic solution into a space is performed using the first opening, the second opening, and the fourth opening. The cross-sectional view for demonstrating the case where the injection of the electrolytic solution into a space is performed using the 1st opening and the 5th opening.

Hereinafter, embodiments in which the power storage device is embodied will be described with reference to FIGS. 1 to 7. The power storage device is, for example, a power storage module used for batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device of this embodiment is a lithium ion secondary battery.

As shown in FIG. 1, the power storage device 10 includes a cell stack 11, a positive electrode energizing plate 12b, and a negative electrode energizing plate 12a. The positive electrode energizing plate 12b and the negative electrode energizing plate 12a face each other with the cell stack 11 interposed therebetween. The positive electrode energizing plate 12b and the negative electrode energizing plate 12a are made of a metal good conductive material. The cell stack 11, the positive electrode energizing plate 12b, and the negative electrode energizing plate 12a are laminated in the stacking direction Z. The stacking direction Z is a direction perpendicular to the outer surface of the positive electrode energizing plate 12b and the negative electrode energizing plate 12a adjacent to the cell stack 11. The cell stack 11 is a laminated body in which a plurality of storage cells 20 are laminated in the stacking direction Z.

The positive electrode energizing plate 12b and the negative electrode energizing plate 12a are electrically connected to the cell stack 11, respectively. Although not shown, terminals are connected to each of the positive electrode energizing plate 12b and the negative electrode energizing plate 12a. The power storage device 10 is charged and discharged through this terminal.

The cell stack 11, the positive electrode energizing plate 12b, and the negative electrode energizing plate 12a are constrained in the stacking direction Z from both sides in the stacking direction Z by a restraining unit or the like. As a result, the restraining load in the stacking direction Z is applied to the cell stack 11, the positive electrode energizing plate 12b, and the negative electrode energizing plate 12a.

Each storage cell 20 includes a positive electrode 31, a negative electrode 21, a separator 40, and a spacer 50. The positive electrode 31 includes a positive electrode current collector 32 and a positive electrode active material layer 33 arranged on the positive electrode surface 32a, which is one surface of the positive electrode current collector 32. The negative electrode 21 includes a negative electrode current collector 22 and a negative electrode active material layer 23 arranged on the negative electrode surface 22a, which is one surface of the negative electrode current collector 22. The positive electrode current collector 32 does not have the positive electrode active material layer 33 on the positive electrode back surface 32b, which is the back surface of the positive electrode surface 32a. The negative electrode current collector 22 does not have the negative electrode active material layer 23 on the negative electrode back surface 22b, which is the back surface of the negative electrode surface 22a.

As shown in FIG. 2, in the present embodiment, the positive electrode current collector 32 and the negative electrode current collector 22 have a rectangular shape in a plan view from the stacking direction Z. The positive electrode active material layer 33 has a rectangular shape smaller than that of the positive electrode current collector 32 in a plan view seen from the stacking direction Z. The negative electrode active material layer 23 has a rectangular shape that is smaller than the negative electrode current collector 22 and larger than the positive electrode active material layer 33 in a plan view from the stacking direction Z.

As shown in FIG. 3, the direction in which the long side of the positive electrode current collector 32 extends is referred to as the first direction X, and the direction in which the short side of the positive electrode current collector 32 extends is referred to as the second direction Y. Although not shown in FIG. 3, the long side of the negative electrode current collector 22 extends along the first direction X, and the short side of the negative electrode current collector 22 extends along the second direction Y. .. The first direction X is a direction orthogonal to the stacking direction Z. The second direction Y is a direction orthogonal to both the stacking direction Z and the first direction X.

As shown in FIG. 1, the separator 40 has a base material layer 40a and adhesive layers 40b provided on both sides of the base material layer 40a in the stacking direction Z. The separator 40 is located between the positive electrode active material layer 33 and the negative electrode active material layer 23 in the stacking direction Z. The adhesive layer 40b provided on one surface of the base material layer 40a faces the positive electrode active material layer 33 in the stacking direction Z. The adhesive layer 40b provided on the other surface of the base material layer 40a faces the negative electrode active material layer 23 in the stacking direction Z. In the separator edge portion 40c, which is the edge portion of the separator 40 in the first direction X, the adhesive layer 40b is adhered to the negative electrode current collector 22.

The separator 40 is located between the positive electrode active material layer 33 and the negative electrode active material layer 23 in the stacking direction Z, thereby separating the positive electrode 31 and the negative electrode 21. The separator 40 is a member that allows charge carriers such as lithium ions to pass through while preventing a short circuit due to contact between the positive electrode 31 and the negative electrode 21.

The positive electrode active material layer 33 and the negative electrode active material layer 23 face each other in the stacking direction Z via the separator 40. In a plan view from the stacking direction Z, the entire positive electrode active material layer 33 overlaps with the negative electrode active material layer 23. In a plan view from the stacking direction Z, the separator 40 has a rectangular shape larger than the positive electrode active material layer 33 and the negative electrode active material layer 23, and the central portion is each of the positive electrode active material layer 33 and the negative electrode active material layer 23. It overlaps with the whole of. The long side of the separator 40 extends along the first direction X, and the short side of the separator 40 extends along the second direction Y.

The spacer 50 is arranged between the positive electrode current collector 32 and the negative electrode current collector 22 that are adjacent to each other in the stacking direction Z. The spacer 50 is joined or fixed to the positive electrode current collector 32 and the negative electrode current collector 22. The spacer 50 contains an insulating material and insulates between the positive electrode current collector 32 and the negative electrode current collector 22 to prevent a short circuit between the two current collectors. Examples of the material constituting the spacer 50 include various resin materials such as polyethylene (PE), polystyrene, ABS resin, modified polypropylene (modified PP), and acrylonitrile styrene (AS) resin.

As shown in FIG. 3, the spacer 50 has a square frame shape in a plan view seen from the stacking direction Z. The spacer 50 includes four edge portions 55, a first edge portion 51, a second edge portion 52, a third edge portion 53, and a fourth edge portion 54. The first edge portion 51 and the third edge portion 53 face each other in the first direction X. The second edge portion 52 and the fourth edge portion 54 face each other in the second direction Y.

As shown in FIG. 1, a space S is partitioned inside the power storage cell 20 by a positive electrode current collector 32, a negative electrode current collector 22, and a spacer 50 that are adjacent to each other in the stacking direction Z. The space S houses the positive electrode active material layer 33, the negative electrode active material layer 23, the separator 40, and the electrolytic solution.

The spacer 50 is adhered to the adhesive layer 40b at the separator edge 40c. The separator edge portion 40c is embedded in the spacer 50 in a state of being sandwiched between the spacer 50 and the negative electrode current collector 22.

Further, the positive electrode 31, the negative electrode 21, the separator 40 and the spacer 50 are laminated to form the storage cell 20, and in a state where the electrolytic solution is injected into the space S, the storage cell 20 is pressurized by a known method such as hot pressing. Then, the adhesive layer 40b of the separator 40 is adhered.

As shown in FIGS. 1 and 3, the spacer 50 includes an opening 60. The opening 60 of the present embodiment is a tubular member made of resin. The axial direction of the opening 60 coincides with the direction extending from the space S toward the outside of the space S through the spacer 50. When the opening 60 is viewed from the outside along the axial direction, the opening 60 has a flat shape in which the dimension in the stacking direction Z is smaller than the dimension in the stacking direction Z and the width direction intersecting the axial direction. The opening 60 is formed, for example, by laminating the widthwise end portions of two films and providing a hollow portion along the axial direction at the center of the widthwise direction. The opening 60 is fixed by the spacer 50 in a state of being sandwiched between the spacer 50 and the negative electrode current collector 22 (separator 40).

Of both ends of the opening 60, one first end 60a closer to the space S is open, and the second end 60b closer to the outside of the other space S is a closing portion 60c that closes the opening. There is. That is, the spacer 50 includes a closing portion 60c that closes the opening of the opening 60 toward the outside of the space S. The closed portion 60c is formed by joining the wall portions of the opening 60 to each other by welding or the like.

The opening end of each of the first end portions 60a of the opening portion 60 protrudes inward of the space S from the spacer main body 56. As a result, each of the openings 60 before the closing portion 60c is provided communicates the space S inside the storage cell 20 with the outside of the space S. Each second end 60b of the opening 60 projects from the inside of the spacer 50 to the outside of the spacer 50.

As shown in FIGS. 3 and 4, the opening 60 of the present embodiment includes a first opening 61, a second opening 62, a third opening 63, a fourth opening 64, and a fifth opening 65. Be prepared. The first opening 61 is arranged at the first edge 51. The second opening 62 is arranged at the second edge 52. The third opening 63 is arranged at the third edge 53. The fourth opening 64 is arranged at the fourth edge 54. The fifth opening 65 is arranged at the second edge 52 and the fourth edge 54.

The first opening 61 penetrates the first edge 51 along the first direction X. Three first openings 61 are arranged in the first edge 51. One first opening 61 is located at an intermediate portion in the second direction Y, and two first openings 61 are located so as to sandwich the first opening 61 in the second direction Y. In the first edge portion 51, the distances between adjacent first openings 61 in the second direction Y in the second direction Y are equal.

The third opening 63 penetrates the third edge 53 along the first direction X. Three third openings 63 are arranged at the third edge 53. One third opening 63 is located at an intermediate portion in the second direction Y, and two third openings 63 are located so as to sandwich the third opening 63 in the second direction Y. In the third edge 53, the distances between adjacent third openings 63 in the second direction Y in the second direction Y are equal.

The three first openings 61 and the three third openings 63 face each other in the first direction X.
The second opening 62 penetrates the second edge 52 along the second direction Y. The second opening 62 is arranged at a position closer to the connection end with the third edge 53 than the connection end with the first edge 51 in the second edge 52.

The fourth opening 64 penetrates the fourth edge 54 along the second direction Y. The fourth opening 64 is arranged at a position closer to the connection end with the third edge 53 than the connection end with the first edge 51 in the fourth edge 54.

Each fifth opening 65 penetrates the second edge 52 and the fourth edge 54 along the second direction Y. The fifth opening 65 is arranged at a position closer to the connection end with the first edge 51 than the connection end with the third edge 53 in each of the second edge 52 and the fourth edge 54. To.

The second opening 62 and the fourth opening 64 face each other in the second direction Y. The fifth opening 65 arranged in the second edge 52 and the fifth opening 65 arranged in the fourth edge 54 face each other in the second direction Y.

In the present embodiment, the state in which the two openings 60 face each other means that the opening surfaces of the two openings 60 facing each other at least partially overlap each other when viewed from the first direction X. To say. Further, in the present embodiment, the first opening 61 has a larger dimension in the width direction than each of the other openings 60. Therefore, the opening area of the first opening 61 is larger than that of each of the other openings 60.

Next, the storage cell 20 before being stacked to form the cell stack 11 will be described in more detail with a focus on the configuration of the spacer 50 and the opening 60.
As shown in FIG. 2, each of the edge portions 55 in the spacer 50 includes a spacer main body 56 and a spacer end portion 57. The spacer main body 56 is arranged between the positive electrode surface 32a of the positive electrode current collectors 32 adjacent to each other in the stacking direction Z and the negative electrode surface 22a of the negative electrode current collector 22. In the first edge portion 51 and the third edge portion 53, the spacer end portion 57 extends outward from the spacer main body 56 to the positive electrode current collector 32 and the negative electrode current collector 22 in the first direction X. Although not shown, in the second edge portion 52 and the fourth edge portion 54, the spacer end portion 57 is outside the positive electrode current collector 32 and the negative electrode current collector 22 in the second direction Y from the spacer main body 56. Extends to. The spacer 50 surrounds the positive electrode active material layer 33 and the negative electrode active material layer 23 by four edge portions 55.

The closed portion 60c is formed in each of the opening portions 60 after the impregnation of the positive electrode active material layer 33 and the negative electrode active material layer 23 with the electrolytic solution is completed. The injection of the electrolytic solution into the space S is performed in each of the openings 60 in a state where the opening of the second end portion 60b is not closed by the closing portion 60c.

When the electrolytic solution is injected into the space S inside the storage cell 20, the three first openings 61 are used as injection ports for injecting the electrolytic solution into the space S. The openings 60 other than the first opening 61 are used as discharge ports for discharging the electrolytic solution from the space S. For injection of the electrolytic solution into the space S, for example, a liquid injection nozzle (not shown) is inserted from the second end portion 60b of the three first openings 61, and the electrolytic solution is injected through the injection nozzle while being injected by a suction device. This can be done by sucking the electrolytic solution from the openings 60 other than the first opening 61.

In each of the storage cells 20, after the impregnation of the electrolytic solution into the space S is completed, the closed portions 60c are formed in all the openings 60. A plurality of storage cells 20 are stacked to form the cell stack 11 in a state where the openings of all the openings 60 are closed by the closed portions 60c.

Next, the configuration of the storage cell 20 will be described in more detail in a state where the cell stack 11 is configured by being stacked.
As shown in FIG. 1, of the two storage cells 20 adjacent to each other in the stacking direction Z, the positive electrode back surface 32b of one storage cell 20 and the negative electrode back surface 22b of the other storage cell 20 are in contact with each other. As a result, in the two storage cells 20 adjacent to each other in the stacking direction Z, the positive electrode 31 of one storage cell 20 and the negative electrode 21 of the other storage cell 20 are in contact with each other.

A pseudo bipolar electrode 25 is formed by the positive electrode 31 and the negative electrode 21 in contact with each other. The positive electrode current collector 32 and the negative electrode current collector 22 in contact with each other function as electrode bodies of the bipolar electrode 25. One bipolar electrode 25 includes a positive electrode current collector 32 and a negative electrode current collector 22 that are in contact with each other in the stacking direction Z, and a positive electrode active material layer 33 and a negative electrode active material layer 23. The bipolar electrodes 25 are alternately laminated with the separator 40 in the stacking direction Z.

The set of the positive electrode current collector 32 and the negative electrode current collector 22 constituting one bipolar electrode 25 is referred to as one current collector 26. A plurality of current collectors 26 are stacked in the stacking direction Z. The positive electrode surface 32a is one surface of the current collector 26 in the stacking direction Z. The negative electrode surface 22a is the other surface of the current collector 26 in the stacking direction Z. Hereinafter, the positive electrode surface 32a is also referred to as a first surface 26b of the current collector 26, and the negative electrode surface 22a is also referred to as a second surface 26a of the current collector 26. It can be said that the positive electrode active material layer 33 is arranged on the first surface 26b of the current collector 26 in the stacking direction Z. It can be said that the negative electrode active material layer 23 is arranged on the second surface 26a of the current collector 26 in the stacking direction Z.

The power storage device 10 includes a positive electrode 31 at one end in the stacking direction Z and a negative electrode 21 at the other end in the stacking direction Z. The positive electrode energizing plate 12b is electrically connected to the positive electrode current collector 32 of the positive electrode 31 located at one end in the stacking direction Z. The negative electrode current-carrying plate 12a is electrically connected to the negative electrode current collector 22 of the negative electrode 21 located at the other end in the stacking direction Z.

In the storage cells 20 adjacent to each other in the stacking direction Z, the spacer end portions 57 of the spacer 50 are joined and integrated. The spacer end 57s of all the storage cells 20 to be laminated in the stacking direction Z are integrated. The integrated spacer end portion 57 is referred to as a sealing body 57a.

The sealing body 57a covers the peripheral portions of the positive electrode current collector 32 and the negative electrode current collector 22. In the first edge portion 51 and the third edge portion 53, the sealing body 57a extends along the short edge portion of the positive electrode current collector 32 and the short edge portion of the negative electrode current collector 22. Although not shown in FIG. 1, in the second edge portion 52 and the fourth edge portion 54, the sealing body 57a is attached to the long edge portion of the positive electrode current collector 32 and the long edge portion of the negative electrode current collector 22. It extends along.

The sealing body 57a extends from the positive electrode current collector 32 arranged at one end of the cell stack 11 in the stacking direction Z to the negative electrode current collector 22 arranged at the other end of the cell stack 11 in the stacking direction Z. Examples of the joining method include heat welding, ultrasonic welding, infrared welding and the like.

The spacer 50 also functions as a sealing portion for sealing the space S between the positive electrode 31 and the negative electrode 21. The spacer 50 can prevent the electrolytic solution contained in the space S from leaking to the outside of the power storage device 10. The spacer 50 can prevent moisture from entering the space S from the outside of the power storage device 10. Further, the spacer 50 can prevent the gas generated from the positive electrode 31 or the negative electrode 21 from leaking to the outside of the power storage device 10 due to, for example, a charge / discharge reaction.

The positive electrode current collector 32 and the negative electrode current collector 22 are chemically inert electric conductors. As the material constituting the positive electrode current collector 32 and the negative electrode current collector 22, for example, a metal material, a conductive resin material, a conductive inorganic material, or the like can be used. Examples of the conductive resin material include a conductive polymer material and a resin obtained by adding a conductive filler to a non-conductive polymer material as needed. The positive electrode current collector 32 and the negative electrode current collector 22 may include a plurality of layers including one or more layers including the above-mentioned metal material or conductive resin material.

A coating layer may be formed on the surface of the positive electrode current collector 32 and the surface of the negative electrode current collector 22 by a known method such as plating treatment or spray coating. The positive electrode current collector 32 and the negative electrode current collector 22 may be formed in, for example, a plate shape, a foil shape, a sheet shape, a film shape, a mesh shape, or the like.

When the positive electrode current collector 32 and the negative electrode current collector 22 are metal foils, for example, aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil, or the like can be used. When stainless steel foil is used as the positive electrode current collector 32 and the negative electrode current collector 22, the mechanical strength of the positive electrode current collector 32 and the negative electrode current collector 22 can be ensured. Examples of the stainless steel foil include SUS304, SUS316, SUS301, and SUS304 specified in JIS G4305: 2015. The positive electrode current collector 32 and the negative electrode current collector 22 may be the alloy foil or the clad foil of the above metal. When the foil-shaped positive electrode current collector 32 and the negative electrode current collector 22 are used, the thickness thereof may be, for example, 1 to 100 μm.

As the material constituting the positive electrode current collecting plate 12b, the same material as the material constituting the positive electrode current collector 32 can be used. As the material constituting the negative electrode current collecting plate 12a, the same material as the material constituting the negative electrode current collector 22 can be used. The positive electrode current collecting plate 12b and the negative electrode current collecting plate 12a may be made of a metal plate thicker than the positive electrode current collector 32 and the negative electrode current collector 22.

The positive electrode active material layer 33 contains a positive electrode active material that can occlude and release charge carriers such as lithium ions. As the positive electrode active material, a material that can be used as a positive electrode active material for a lithium ion secondary battery, such as a lithium composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, and a polyanionic compound, may be adopted. Further, two or more kinds of positive electrode active materials may be used in combination.

The negative electrode active material layer 23 can be used without particular limitation as long as it is a simple substance, an alloy, or a compound capable of occluding and releasing charge carriers such as lithium ions. For example, examples of the negative electrode active material include Li, carbon, a metal compound, an element that can be alloyed with lithium, or a compound thereof. Examples of carbon include natural graphite, artificial graphite, hard carbon (non-graphitizable carbon), and soft carbon (easy graphitizable carbon). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon and tin.

The positive electrode active material layer 33 and the negative electrode active material layer 23 are also simply referred to as an active material layer. The active material layer contains a conductive auxiliary agent, a binder, an electrolyte (polymer matrix, an ionic conductive polymer, an electrolytic solution, etc.) for enhancing electrical conductivity, and an electrolyte supporting salt for enhancing ionic conductivity, if necessary. (Lithium salt) and the like may be further contained. The components contained in the active material layer, the compounding ratio of the components, and the thickness of the active material layer are not particularly limited, and conventionally known findings regarding a lithium ion secondary battery can be appropriately referred to. The thickness of the active material layer is, for example, 2 to 150 μm. In order to form the active material layer on the surface of the current collector 26, a conventionally known method such as a roll coating method may be used. In order to improve the thermal stability of the positive electrode 31 and the negative electrode 21, a heat-resistant layer may be provided on at least one of the first surface 26b and the second surface 26a of the current collector 26, or on the surface of the active material layer. The heat-resistant layer may contain, for example, inorganic particles and a binder, and may also contain an additive such as a thickener.

The conductive auxiliary agent is added to increase the conductivity of the positive electrode 31 or the negative electrode 21. Conductive aids are, for example, acetylene black, carbon black, graphite and the like.
Examples of the binder include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide-based resins such as polyimide and polyamideimide, resins containing an alkoxysilyl group, and poly (poly). Meta) Acrylic resins such as acrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, sodium alginate, arginates such as ammonium alginate, water-soluble cellulose ester cross-linking products, starch-acrylic acid graft polymers can be exemplified. can. These binders can be used alone or in combination. As the solvent, for example, water, N-methyl-2-pyrrolidone (NMP) and the like are used.

The base material layer 40a may be, for example, a porous sheet or a non-woven fabric containing a polymer that absorbs and retains an electrolyte. Examples of the material constituting the base material layer 40a include polypropylene, polyethylene, polyolefin, polyester and the like. The base material layer 40a may have a single-layer structure or a multi-layer structure. The multilayer structure may have, for example, a ceramic layer as a heat-resistant layer. The base material layer 40a may be impregnated with an electrolyte, or the base material layer 40a itself may be composed of an electrolyte such as a polymer electrolyte or an inorganic type electrolyte.

The electrolyte impregnated in the base material layer 40a is, for example, an electrolyte solution which is a liquid electrolyte containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, or a polymer gel containing an electrolyte held in a polymer matrix. Examples include electrolytes.

When the base material layer 40a is impregnated with an electrolytic solution, the electrolyte salts thereof include LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (FSO ₂ ) ₂ , and LiN (CF ₃ SO ₂ ) ₂ . And other known lithium salts can be used. Further, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers can be used. In addition, you may use two or more kinds of these known solvent materials in combination.

The positive electrode current collector 32 in this embodiment is an aluminum foil. The negative electrode current collector 22 in this embodiment is a copper foil. The positive electrode active material layer 33 in the present embodiment contains olivine-type lithium iron phosphate (LiFePO ₄ ) as a composite oxide. The negative electrode active material layer 23 in the present embodiment contains graphite as a carbon-based material. In the present embodiment, the base material layer 40a is impregnated with the electrolytic solution.

Next, a method of injecting the electrolytic solution into the space S of the storage cell 20 will be described.
The injection of the electrolytic solution into the space S of the storage cell 20 is performed on the storage cell 20 before stacking to form the cell stack 11. The storage cell 20 when the electrolytic solution is injected is in a state in which the opening of the second end portion 60b is not closed by the closing portion 60c. In the present embodiment, the first opening 61 is used as an injection port for injecting the electrolytic solution into the space S, and the other opening 60 is used as an discharge port for discharging the electrolytic solution from the space S. The opening 60 for sucking the electrolytic solution is changed in the order of the third opening 63, the second opening 62, the fourth opening 64, and the fifth opening 65. As a result, the opening 60 used as the discharge port is sequentially changed.

As shown in FIG. 5, first, the three first openings 61 are used as injection ports, and the three third openings 63 are used as discharge ports. In this case, in each of the third openings 63, the electrolytic solution is sucked from the second end portion 60b as shown by the arrow of the alternate long and short dash line in FIG. As a result, the electrolytic solution flows into the space S from the first end 60a of each of the first openings 61 through the inside of the three first openings 61, as shown by the arrows of the two-dot chain line in FIG. In the space S, the electrolytic solution flows from the three first openings 61 toward the three third openings 63. When the electrolytic solution reaches each of the third openings 63, the electrolytic solution is discharged from the space S through each of the third openings 63.

Subsequently, as shown in FIG. 6, the three first openings 61 are continuously used as injection ports, and the openings 60 used as discharge ports are used from the third opening 63 to the second opening 62 and the fourth opening. Change to 64. In this case, the suction of the electrolytic solution from each of the third openings 63 is stopped. Further, in the second opening 62 and the fourth opening 64, the electrolytic solution is sucked from the second end portion 60b as shown by the arrow of the alternate long and short dash line in FIG. As a result, as shown by the alternate long and short dash line in FIG. 6, the electrolytic solution is directed from the three first openings 61 to each of the second opening 62 and the fourth opening 64 in the space S. It will flow. When the electrolytic solution reaches each of the second opening 62 and the fourth opening 64, the electrolytic solution is discharged from the space S through each of the second opening 62 and the fourth opening 64.

The second opening 62 is located at an intermediate position between the first opening 61 arranged in the first edge 51 at the position closest to the second edge 52 and the first edge 51 in the first direction X. A large amount of electrolytic solution flows from the first opening 61 to be arranged. The path of the electrolytic solution flowing from the first opening 61 arranged in the first edge 51 at the position closest to the second edge 52 toward the second opening 62 is called the first path R1. The path of the electrolytic solution flowing from the first opening 61 arranged at the intermediate position of the first edge 51 in the first direction X toward the second opening 62 is referred to as a second path R2. In FIG. 6, the first path R1 and the second path R2 are schematically shown by arrows of a two-dot chain line, respectively.

The fourth opening 64 is arranged at an intermediate position between the first opening 61 arranged in the first edge 51 at the position closest to the fourth edge 54 and the first edge 51 in the first direction X. A large amount of electrolytic solution flows from the first opening 61. The path of the electrolytic solution flowing from the first opening 61 arranged in the first edge 51 at the position closest to the fourth edge 54 toward the fourth opening 64 is called the third path R3. The path of the electrolytic solution flowing from the first opening 61 arranged at the intermediate position of the first edge 51 in the first direction X toward the fourth opening 64 is referred to as a fourth path R4. In FIG. 6, the third path R3 and the fourth path R4 are schematically shown by arrows of a two-dot chain line, respectively.

Here, the second opening 62 and the fourth opening 64 face each other in the second direction Y. Therefore, the first path R1 and the third path R3 have the same length, and the second path R2 and the fourth path R4 have the same length. As a result, the path of the electrolytic solution flowing from the first opening 61 to the second opening 62 and the path of the electrolytic solution flowing from the first opening 61 toward the fourth opening 64 have the same path length. It can be said that

Subsequently, as shown in FIG. 7, the three first openings 61 are continuously used as injection ports, and the openings 60 used as discharge ports are used as two fifth openings from the second opening 62 and the fourth opening 64. Change to opening 65. In this case, the suction of the electrolytic solution from the second opening 62 and the fourth opening 64 is stopped. Further, in each of the fifth openings 65, as shown by the alternate long and short dash line in FIG. 7, the electrolytic solution is sucked from the second end portion 60b. As a result, as shown by the alternate long and short dash line in FIG. 7, the electrolytic solution flows from the three first openings 61 to each of the five fifth openings 65 in the space S. When the electrolytic solution reaches each of the fifth openings 65, the electrolytic solution is discharged from the space S through each of the fifth openings 65.

Then, the injection of the electrolytic solution through the first opening 61 and the suction of the electrolytic solution through the fifth opening 65 are stopped. This completes the impregnation of the electrolytic solution into the space S of the storage cell 20. When the impregnation of the electrolytic solution into the space S is completed, the closing portions 60c are formed in all the openings 60 in the storage cell 20 to close the openings of the second end portion 60b in all the openings 60. Then, a plurality of storage cells 20 are stacked to form the cell stack 11.

Next, the operation of this embodiment will be described.
By using the first opening 61 as an injection port for injecting the electrolytic solution into the space S, and using the second opening 62 and the third opening 63 as an discharge port for discharging the electrolytic solution from the space S. , The positive electrode active material layer 33 and the negative electrode active material layer 23 can be impregnated with the electrolytic solution. Each of the first opening 61, the second opening 62, and the third opening 63 is arranged at different edges 55 of the spacer 50. By injecting the electrolytic solution into the space S through the first opening 61 while discharging the electrolytic solution from the second opening 62 and the third opening 63, the space S near the three edges 55 of the spacer 50 The electrolytic solution can be flowed into. The electrolytic solution immediately after flowing into the space S from the first opening 61 flows along the first direction X, which is the penetrating direction of the first opening 61 to the spacer 50. The electrolytic solution immediately before reaching the second opening 62 flows along the second direction Y, which is the penetrating direction of the second opening 62 to the spacer 50. The electrolytic solution immediately before reaching the third opening 63 flows along the first direction X, which is the penetrating direction of the third opening 63 to the spacer 50. The first direction X and the second direction Y intersect each other. Therefore, the electrolytic solution reaches the ends of the positive electrode active material layer 33 and the negative electrode active material layer 23 in the direction intersecting the inflow direction of the electrolytic solution.

According to the above embodiment, the following effects can be obtained.
(1) The first opening 61 is used as an injection port for injecting the electrolytic solution into the space S, and the second opening 62 and the third opening 63 are used as discharge ports for discharging the electrolytic solution from the space S. I am using it. As a result, each of the first opening 61, the second opening 62, and the third opening 63 is arranged at different edges 55 of the spacer 50. Therefore, since the electrolytic solution can flow into the space S near the three edge portions 55, uneven impregnation of the electrolytic solution can be suppressed.

(2) The electrolytic solution is flowing from the first opening 61 toward the second opening 62 and the third opening 63. As a result, the electrolytic solution can flow toward the second edge portion 52 and the third edge portion 53. Here, the first edge portion 51 is arranged on one side in the first direction X with respect to the positive electrode active material layer 33 and the negative electrode active material layer 23. The second edge portion 52 is arranged on one side in the second direction Y with respect to the positive electrode active material layer 33 and the negative electrode active material layer 23. Therefore, the flow of the electrolytic solution from the first opening 61 to the second opening 62 becomes a flow from the first edge 51 to the second edge 52. By this flow of the electrolytic solution, the electrolytic solution can be impregnated at the ends of the positive electrode active material layer 33 and the negative electrode active material layer 23 in the direction intersecting the inflow direction of the electrolytic solution. On the other hand, the third edge portion 53 faces the first edge portion 51 in the first direction X. Therefore, the flow of the electrolytic solution from the first opening 61 to the third opening 63 is a linear flow from the first edge 51 to the third edge 53. The linear flow of the electrolytic solution allows the electrolytic solution to be impregnated at the ends of the positive electrode active material layer 33 and the negative electrode active material layer 23 in the inflow direction of the electrolytic solution. Therefore, the ends of the positive electrode active material layer 33 and the negative electrode active material layer 23 in the direction intersecting the inflow direction of the electrolytic solution, and the end portions of the positive electrode active material layer 33 and the negative electrode active material layer 23 in the inflow direction of the electrolytic solution. Since the electrolytic solution can be impregnated at each end of the above, uneven impregnation of the electrolytic solution can be further suppressed.

(3) The first opening 61 and the third opening 63 face each other in the first direction X. Therefore, the path of the electrolytic solution flowing from the first opening 61 to the third opening 63 is shorter than that in the case where the first opening 61 and the third opening 63 do not face each other in the first direction X. Therefore, since the time required for the electrolytic solution to reach the first opening 61 to the third opening 63 can be shortened, the working time related to the impregnation of the electrolytic solution can be shortened.

(4) The second opening 62 is arranged at a position closer to the connection end with the third edge 53 than the connection end with the first edge 51 in the second edge 52. In this case, the electrolytic solution flowing from the first opening 61 to the second opening 62 flows through the portion of the space S near the third edge 53. Therefore, as compared with the case where the second opening 62 is arranged at a position closer to the connection end with the first edge 51 than the connection end with the third edge 53 in the second edge 52. , The range of the space S through which the electrolytic solution flows in the first direction X can be increased. Therefore, uneven impregnation of the electrolytic solution can be further suppressed.

(5) Of the first opening 61, the second opening 62, the third opening 63, and the fourth opening 64, the first opening 61, which is a part of the opening 60, is used as an injection port, and is also used. The second opening 62, the third opening 63, and the fourth opening 64, which are the other openings 60, are used as discharge ports. As a result, the positive electrode active material layer 33 and the negative electrode active material layer 23 are impregnated with the electrolytic solution. Each of the first opening 61, the second opening 62, the third opening 63, and the fourth opening 64 is arranged at different edges 55 of the spacer 50. By flowing the electrolytic solution from the first opening 61 toward the second opening 62, the third opening 63, and the fourth opening 64, the electrolytic solution can flow into the space S near the four edges 55. can. Therefore, as compared with the case where the opening 60 is arranged only on the three edges 55 of the spacer 50, the impregnation unevenness of the electrolytic solution can be further suppressed.

(6) The electrolytic solution is flowing from the first opening 61 toward the second opening 62 and the fourth opening 64. As a result, the electrolytic solution can flow toward the second edge portion 52 and the fourth edge portion 54. Here, the second edge portion 52 is arranged on one side in the second direction Y with respect to the positive electrode active material layer 33 and the negative electrode active material layer 23. The fourth edge portion 54 faces the second edge portion 52 in the second direction Y. Therefore, the electrolytic solution flows from the first opening 61 to the second opening 62 and the fourth opening 64, so that the positive electrode active material layer 33 and the negative electrode active material layer 23 in the direction intersecting the inflow direction of the electrolytic solution. Both ends can be impregnated with electrolyte. Therefore, uneven impregnation of the electrolytic solution can be further suppressed.

(7) The second opening 62 and the fourth opening 64 face each other in the second direction Y. Therefore, the path of the electrolytic solution flowing from the first opening 61 to the second opening 62 and the path of the electrolytic solution flowing from the first opening 61 toward the fourth opening 64 have the same path length. Become. Therefore, since the electrolytic solution can be impregnated while discharging the electrolytic solution from both the second opening 62 and the fourth opening 64, the working time related to the impregnation of the electrolytic solution can be shortened.

(8) The fourth opening 64 is arranged at a position closer to the connection end with the third edge 53 than the connection end with the first edge 51 in the fourth edge 54. In this case, the electrolytic solution flowing from the first opening 61 to the fourth opening 64 flows through the portion of the space S near the third edge 53. Therefore, as compared with the case where the fourth opening 64 is arranged at a position closer to the connection end with the first edge 51 than the connection end with the third edge 53 in the fourth edge 54. Since the range of the space S through which the electrolytic solution flows can be increased in the first direction X, uneven impregnation of the electrolytic solution can be further suppressed.

The above embodiment can be modified and implemented as follows. Each of the above embodiments and the following modifications can be implemented in combination with each other within a technically consistent range.

○ The first direction X, which is the penetrating direction of the first opening 61 and the third opening 63 to the spacer 50, and the second direction, which is the penetrating direction of the second opening 62 and the fourth opening 64 to the spacer 50. Y and Y do not have to be orthogonal to each other, and may intersect with each other. Further, the first direction X and the second direction Y do not have to be orthogonal to the stacking direction Z, and may intersect with each other. Also in this case, since the electrolytic solution can be impregnated at the ends of the positive electrode active material layer 33 and the negative electrode active material layer 23 in the direction intersecting the inflow direction of the electrolytic solution, uneven impregnation of the electrolytic solution can be suppressed.

○ The second opening 62 may be used as an injection port for injecting the electrolytic solution into the space S, and the first opening 61 may be used as a discharge port for discharging the electrolytic solution from the space S. Further, if one of the first opening 61 and the second opening 62 is an injection port and the other is a discharge port, the other opening 60 may be either an injection port or a discharge port.

○ The electrolytic solution may be injected from a plurality of openings 60. In this case, for example, the electrolytic solution is injected from the openings 60 provided in the first edge 51 and the second edge 52, and electrolyzed from the openings 60 provided in the third edge 53 and the fourth edge 54. It is preferable to perform injection and discharge through a plurality of openings 60 having different penetration directions so as to drain the liquid.

○ The width direction dimension of the opening 60 used as the inlet may be larger than the width direction dimension of the opening 60 used as the discharge port, or less than or equal to the width direction dimension of the opening 60 used as the discharge port. You may. Regardless of whether it is used as an inlet or an outlet, the dimensions in the width direction may be different for each of the openings 60.

○ The dimension in the thickness direction that coincides with the stacking direction Z of the opening 60 used as the inlet may be larger than the dimension in the thickness direction of the opening 60 used as the discharge port, or the thickness of the opening 60 used as the discharge port. It may be less than or equal to the dimension in the direction. Regardless of whether it is used as an inlet or an outlet, the dimensions in the thickness direction may be different for each of the openings 60.

○ The order of changing the openings 60 used as discharge ports when injecting the electrolytic solution into the space S is not limited to the order of changing the above-described embodiment.
○ By shifting the suction timing of the electrolytic solution of the second opening 62 and the fourth opening 64, the injection of the electrolytic solution using the second opening 62 as the discharge port and the use of the fourth opening 64 as the discharge port. The injection of the electrolytic solution that has been used may be performed at a different timing.

○ The closing portion 60c may be provided in the opening 60 other than joining the walls of the opening 60 to each other. For example, the closing portion 60c may be a lid member separate from the opening 60. In this case, by attaching the closing portion 60c to the second end portion 60b of the opening portion 60, the opening in the second end portion 60b can be closed by the closing portion 60c.

○ A part or all of the opening 60 is not limited to the one formed by laminating the widthwise end portions of two films. For example, a through hole may be formed in the edge portion 55 of the spacer 50, and this through hole may be used as the opening 60. In this case, by inserting the nozzle for injecting the electrolytic solution into the through hole, the opening 60 can be used as an injection port for injecting the electrolytic solution into the space S. Further, a closing portion may be provided at the outer end of the through hole in the spacer 50. Also in this case, the opening penetrates the spacer as a whole due to the through hole and the closing portion.

O One or both of the two fifth openings 65 may be omitted from the spacer 50.
○ The second opening 62 and the fourth opening 64 do not have to face each other in the second direction Y.

○ The position of the second opening 62 in the second edge 52 is closer to the connection end with the first edge 51 than the connection end with the third edge 53 in the second edge 52. It may be a position or an intermediate position between the connection end portion with the third edge portion 53 and the connection end portion with the first edge portion 51.

○ The position of the fourth opening 64 in the fourth edge 54 is closer to the connection end with the first edge 51 than the connection end with the third edge 53 in the fourth edge 54. It may be a position or an intermediate position between the connection end portion with the third edge portion 53 and the connection end portion with the first edge portion 51.

○ The number of arrangements of the second opening 62 in the second edge 52 may be two or more. The number of arrangements of the fourth opening 64 in the fourth edge 54 may be two or more. The number of arrangements of the second opening 62 in the second edge 52 and the number of arrangements of the fourth opening 64 in the fourth edge 54 may be different.

○ The fourth opening 64 may be omitted from the spacer 50.
○ The number of arrangements of the first opening 61 in the first edge 51 may be two or less, or may be four or more. The number of arrangements of the third opening 63 in the third edge 53 may be two or less, or may be four or more. The number of arrangements of the first opening 61 in the first edge 51 and the number of arrangements of the third opening 63 in the third edge 53 may be different.

○ The first opening 61 and the third opening 63 do not have to face each other in the first direction X. When the number of arrangements of the first opening 61 in the first edge 51 and the number of arrangements of the third opening 63 in the third edge 53 are each, a part of the first openings. The 61 and a part of the third opening 63 may face each other in the first direction X, or all the first openings 61 and all the third openings 63 may not face each other.

○ The shapes of the positive electrode current collector 32 and the negative electrode current collector 22 are not limited to the rectangular shape in the plan view seen from the stacking direction Z. For example, the positive electrode current collector 32 and the negative electrode current collector 22 may have a square shape in a plan view seen from the stacking direction Z. In this case, the first edge portion 51 and the third edge portion 53 are a pair of edge portions extending in the second direction Y of the positive electrode current collector 32 and a pair of edge portions extending in the second direction Y of the negative electrode current collector 22. And extends along. The second edge portion 52 and the fourth edge portion 54 have a pair of edge portions extending in the first direction X of the positive electrode current collector 32 and a pair of edge portions extending in the first direction X of the negative electrode current collector 22. It extends along.

○ A part or all of the four edges 55 of the spacer 50 may be separate bodies. In this case, by arranging the four edge portions 55 so as to surround the positive electrode active material layer 33 and the negative electrode active material layer 23, the spacer 50 can be formed into a square frame shape in a plan view seen from the stacking direction Z.

○ One or both of the first edge portion 51 and the third edge portion 53 may be discontinuously arranged along the second direction Y. One or both of the second edge 52 and the fourth edge 54 may be discontinuously arranged along the first direction X.

○ The current collector 26 of the bipolar electrode 25 is not limited to the one composed of the two members of the positive electrode current collector 32 and the negative electrode current collector 22 as in the above embodiment. For example, the current collector 26 may be composed of one member. In this case, one surface of the current collector 26 in the stacking direction Z is the first surface 26b having the positive electrode active material layer 33. The other surface of the current collector 26 in the stacking direction Z is the second surface 26a having the negative electrode active material layer 23.

○ The power storage device 10 may be a secondary battery other than a lithium ion secondary battery such as a nickel hydrogen secondary battery. The power storage device 10 may be an electric double layer capacitor or an all-solid-state battery.

S ... space, 10 ... power storage device, 22 ... negative electrode current collector, 23 ... negative electrode active material layer, 26 ... current collector, 26a ... second surface, 26b ... first surface, 32 ... positive electrode current collector, 33 ... Positive electrode active material layer, 50 ... spacer, 51 ... first edge, 52 ... second edge, 53 ... third edge, 54 ... fourth edge, 55 ... edge, 60 ... opening, 61 ... 1 opening, 62 ... 2nd opening, 63 ... 3rd opening, 64 ... 4th opening.

Claims (8)

With a current collector that stacks multiple layers in the stacking direction,
A positive electrode active material layer arranged on the first surface, which is one surface of the current collector in the stacking direction,
A negative electrode active material layer arranged on the second surface, which is the other surface of the current collector in the stacking direction,
A power storage device that is arranged between two adjacent current collectors in the stacking direction and includes a positive electrode active material layer and a spacer surrounding the negative electrode active material layer.
The spacer has a square frame shape in a plan view from the stacking direction, and is arranged on one side of the positive electrode active material layer and the negative electrode active material layer in a first direction intersecting the stacking direction. A first edge portion, a second edge portion arranged on one side in a second direction intersecting both the stacking direction and the first direction, and a third edge portion facing the first edge portion in the first direction. It comprises a portion and an opening extending outward from the space partitioned by the two adjacent current collectors and the spacer in the stacking direction.
The opening is
A first opening that penetrates the first edge along the first direction,
A second opening that penetrates the second edge along the second direction,
A power storage device including a third opening that penetrates the third edge portion along the first direction. The first opening is an injection port for injecting an electrolytic solution into the space.
The power storage device according to claim 1, wherein the second opening and the third opening are discharge ports for discharging the electrolytic solution from the space. The first opening is an injection port for injecting an electrolytic solution into the space.
The third opening is a discharge port for discharging the electrolytic solution from the space.
The power storage device according to claim 1 or 2, wherein the first opening and the third opening face each other in the first direction. The first opening is an injection port for injecting an electrolytic solution into the space.
The second opening is a discharge port for discharging the electrolytic solution from the space.
Claims 1 to claim that the second opening is arranged at a position of the second edge portion closer to the connection end portion with the third edge portion than the connection end portion with the first edge portion. The power storage device according to any one of 3. The spacer comprises a fourth edge facing the second edge in the second direction.
The power storage device according to any one of claims 1 to 4, wherein the opening includes a fourth opening arranged at the fourth edge. The first opening is an injection port for injecting an electrolytic solution into the space.
The power storage device according to claim 5, wherein the second opening and the fourth opening are discharge ports for discharging the electrolytic solution from the space. The power storage device according to claim 6, wherein the second opening and the fourth opening face each other in the second direction. The first opening is an injection port for injecting an electrolytic solution into the space.
The fourth opening is a discharge port for discharging the electrolytic solution from the space.
Claims 5 to claim that the fourth opening is arranged at a position of the fourth edge portion closer to the connection end portion with the third edge portion than the connection end portion with the first edge portion. The power storage device according to any one of 7.

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