JP2014082071A - Electricity storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To possibly suppress a short circuit failure caused due to foreign matters present inside an electricity storage device housing.SOLUTION: An electricity storage device includes an electricity storage element in which electrode plates 31, 32 each having an active material layer formed on the surface thereof and a sheet-like separator 33 are alternately laminated to be arranged and the separator 33 extends from an edge of the electrode plates 31, 32 at one end of the electrode plates 31, 32. A first projecting part 34 projecting in the lamination direction is formed at a part extending from the edge of the electrode plates 31, 32 in the separator 33, and the first projecting part 34 and the separators 33 adjacent in the lamination direction are arranged at a place where the first projecting part 34 is formed, while a gap is formed therebetween.

Description

  In the present invention, electrode plates each having an active material layer formed on a surface thereof and sheet-like separators are alternately stacked, and the separator extends at one end of the electrode plate from the edge of the electrode plate. The present invention relates to a power storage device including the power storage element.

In such a power storage device, in the power storage element, electrical insulation between the positive and negative electrode plates is achieved by arranging a separator between the electrode plate on which the positive electrode active material layer is formed and the electrode plate on which the negative electrode active material layer is formed. And movement of ions by permeation of the electrolyte.
If the electrical insulation function between the electrode plates by the separator is impaired due to the structure as described above, a so-called short-circuit failure occurs.
One cause of such a short-circuit failure is the presence of foreign matter in the power storage device as described in Patent Document 1 below. For example, in a manufacturing process of the power storage device, a part of the metal member in the housing of the power storage device is detached and becomes a minute metal piece.
Incidentally, in the following Patent Document 1, the shape of the electrode plate is devised so that the influence is reduced as much as possible even when a foreign object interferes with the power storage element.

JP 2012-079501 A

Therefore, although the conventional configuration is effective as a countermeasure against foreign matter existing in the power storage device casing, further improvement is required from the viewpoint of further improving the reliability of the power storage device.
The present invention has been made in view of such circumstances, and an object of the present invention is to suppress as much as possible a short-circuit failure caused by a foreign substance present in the power storage device housing.

  According to a first aspect of the present application, an electrode plate having an active material layer formed on a surface thereof and a sheet-like separator are alternately stacked and disposed at one end of the electrode plate. A power storage device including a power storage element extending from an edge, wherein the first power protrusion protrudes in a stacking direction in a portion of the power storage element that extends from an edge of the electrode plate in the separator. The separators adjacent to each other in the stacking direction are arranged in a state where a gap is left at the place where the first protrusions are formed.

That is, when a structure in which the electrode plates are sandwiched between sheet-shaped separators and a structure in which these are stacked, by forming a first convex portion protruding in the stacking direction of the separator and the electrode plates at one end of the separator, The gap between the adjacent separators is set as the set interval at the location where the first protrusion is formed.
As a result of the analysis of the short-circuit failure, the foreign matter that enters the power storage element is almost always generated during the processing of the component parts in the manufacturing process of the power storage device, and it can be grasped how large it is.
By setting the set interval based on the analysis result of the foreign matter, the foreign matter is present in the space between the separators adjacent in the stacking direction, that is, in the existence space of the electrode plate on which the active material layer is formed. Intrusion is prevented, and foreign matter is prevented from entering between the separator and the electrode plate.
Considering only the prevention of foreign substance intrusion, it is preferable to eliminate the gap between the separators at the first convex portion formation location. However, if the gap between the separators disappears at all, In the step of injecting the electrolytic solution in the process, the working efficiency is lowered.
That is, the separator blocks the injected electrolyte from entering the power storage element. Although the separator is made of a material that allows the electrolytic solution to pass therethrough, a certain amount of time is required for the electrolytic solution to pass therethrough, thereby reducing the working efficiency of the electrolytic solution injection.
In this regard, as described above, by ensuring a gap between the separators, it is possible to suppress the deterioration of the electrolyte injection workability as much as possible.

Further, according to a second invention of the present application, in addition to the configuration of the first invention, the first convex portion is formed on each of the opposing surfaces of the separators adjacent in the stacking direction. The gap is formed between the first protrusions protruding from the first projection.
That is, by forming the first convex portion on each of the separators adjacent in the stacking direction and having the gap of the set interval at the location where the first convex portion is formed, only one separator is used. Since the height of the first convex portion can be reduced compared to the case where the first convex portion is formed, the first convex portion can be easily formed, and the manufacturing cost of the separator can be reduced. Reduction can be achieved.

According to a third invention of the present application, in addition to the configuration of the first or second invention, the electrode plate has a positive electrode plate and a negative electrode plate alternately arranged in the stacking direction. The first protrusion is disposed only on the surface facing the positive electrode plate.
In other words, the inventor of the present invention has found that the short-circuit failure caused by the invading foreign matter is characteristically caused by the foreign matter on the positive electrode plate breaking through the separator.
This is because foreign substances such as copper that have entered the space between the separators adjacent in the stacking direction elute on the electrode side of the positive electrode and deposit and grow on the electrode side of the negative electrode with the charge and discharge of the power storage device. It is presumed to break through the separator.
Therefore, by forming the first convex portion only on the surface facing the positive electrode plate, an increase in the manufacturing cost of the separator accompanying the formation of the first convex portion is suppressed as much as possible. Thereby, it can contribute to the manufacturing cost reduction of an electrical storage element.

  According to a fourth invention of the present application, in addition to the configuration of the first or second invention, the electrode plate has a positive electrode plate and a negative electrode plate alternately arranged in the stacking direction. And an unformed portion that does not form the active material layer is set at one end of the electrode plate, and the unformed portion of the positive electrode plate and the unformed portion of the negative electrode plate are The unformed portion of the electrode plate that is disposed in a position that does not overlap in the stacking direction as viewed from the end of the separator, and that is sandwiched between separators adjacent in the stacking direction. Is formed at an end portion where the non-existing portion does not exist, and the separator has a gap between the non-formed portion and the non-formed portion protruding in the stacking direction at a position overlapping the existing position of the non-formed portion in the stacking direction. The convex part is formed.

In other words, the electrode plate is often provided with the above-mentioned unformed portion in which the surface of the electrode plate is exposed without forming an active material layer for the purpose of electrical connection with an external circuit, etc. The non-formed part is disposed so that the non-formed part of the positive electrode plate and the non-formed part of the negative electrode plate do not overlap in the stacking direction view.
Since the unformed part extends beyond the edge of the separator, the first convex part is formed at the end where there is no unformed part in the electrode plate sandwiched between the separators adjacent in the stacking direction, The set interval set for the first convex portion is secured.
Therefore, in the location where the non-formed part is present, the first convex part does not prevent foreign matter from entering, and the first convex part alone does not necessarily have the effect of preventing foreign matter from entering the power storage element as a whole. Not enough.
Therefore, in the location where the non-formed part is present, a second convex part that protrudes from the separator in the stacking direction and has a gap of a set interval between the non-formed part is provided, thereby preventing foreign matter from entering. In addition, the workability of injecting the electrolyte can be improved.
Note that the set interval set for the second convex portion does not necessarily match the set interval set for the first convex portion.

According to a fifth aspect of the present application, in addition to the configuration of the fourth aspect, the first convex portion and the second convex portion are formed only on a surface facing the positive electrode plate. ing.
That is, the short-circuit failure due to the invading foreign matter is characteristically based on the knowledge that the foreign matter on the positive electrode plate breaks through the separator, and the first convex portion and the second convex portion are By forming it only on the surface facing the electrode plate of the positive electrode, an increase in the manufacturing cost of the separator accompanying the formation of the first convex portion and the second convex portion is suppressed as much as possible. Thereby, it can contribute to the manufacturing cost reduction of an electrical storage element.

In addition to the configuration of any one of the first to fifth inventions, the sixth invention of the present application is such that the electrode plate and the separator are formed in a long band shape, and the first convex portion is The separator is formed in a portion extending in the lateral width direction from the edge of the electrode plate in the separator, and the long strip-shaped electrode plate and the separator are wound around a winding axis extending in the lateral width direction. Has been.
That is, when a power storage element is configured as a so-called winding type power storage element by winding a long strip electrode plate and a separator, intrusion of foreign matter from the end in the lateral width direction becomes a problem.
Therefore, the first convex portion is formed in a portion extending in the lateral width direction from the edge of the electrode plate in the separator to prevent foreign matter from entering from the lateral width direction end portion.
Accordingly, in a so-called wound type power storage element, it is possible to suppress as much as possible a short-circuit failure due to a foreign substance present in the power storage device housing.

  According to the invention of the present application, by forming the first convex portion at the end of the separator, the gap between the separators adjacent in the stacking direction is narrowed, and foreign matter enters between the separator and the electrode plate. Therefore, it is possible to suppress as much as possible a short-circuit failure due to a foreign substance existing in the power storage device housing.

1 is an external perspective view of a secondary battery according to an embodiment of the present invention. The perspective view which shows the inside of the secondary battery concerning embodiment of this invention. The perspective view which shows the structure of the electric power generation element concerning embodiment of this invention. The expanded sectional view which shows the lamination | stacking state of the electric power generation element concerning embodiment of this invention The expanded sectional view which shows the lamination | stacking state of the electric power generation element concerning embodiment of this invention The expanded sectional view showing the separator concerning an embodiment of the invention The expanded sectional view of the edge part of the electric power generation element concerning embodiment of this invention The expanded sectional view which shows the lamination | stacking state of the electric power generation element concerning another embodiment of this invention The expanded sectional view which shows the lamination | stacking state of the electric power generation element concerning another embodiment of this invention The expanded sectional view showing the separator concerning another embodiment of the present invention. The expanded sectional view of the edge part of the electric power generation element concerning another embodiment of this invention

Hereinafter, an embodiment in which the power storage device of the present invention is configured as a battery, particularly a secondary battery, as an example of the power storage device will be described with reference to the drawings.
In the present embodiment, a nonaqueous electrolyte secondary battery (more specifically, a lithium ion battery) will be described as an example of the secondary battery.

As shown in the perspective view of FIG. 1, the nonaqueous electrolyte secondary battery RB includes a battery casing BC (hereinafter referred to as “casing”) formed by welding a cover 1 on the open surface of a can 1. BC ”). The lid portion 2 is formed of a strip-shaped rectangular plate material, and a terminal bolt 5 that is a positive electrode terminal and a terminal bolt 7 that is a negative electrode terminal are attached to a surface on the outer side of the casing BC. It has been.
The can 1 is a flat rectangular parallelepiped in accordance with the shape of the lid portion 2, and thus has a flat and substantially rectangular parallelepiped shape as a whole of the casing BC, and the internal space of the casing BC is also flat and substantially rectangular. It has become.

On the inner side of the casing BC, the storage element 3 and current collectors 4 and 6 indicated by a two-dot chain line in FIG. 2 are housed and arranged in a state where they are partially immersed in the electrolyte. FIG. 2 shows the inner side of the casing BC as a perspective view looking up from the lower side with the can 1 removed. In the present embodiment, secondary battery RB is illustrated as the power storage device, and “power storage element 3” is hereinafter referred to as “power generation element 3” using a general name as a battery.
The current collectors 4 and 6 are members for electrically connecting the power generation element 3 and the terminal bolts 5 and 7, and both are formed of a conductor.
The current collector 4 and the current collector 6 have a relationship in which substantially the same shape is arranged symmetrically, but the materials are different, and the current collector 4 on the positive electrode side is mainly composed of aluminum. The current collector 6 on the negative electrode side is formed of a material mainly composed of copper.

  The schematic shape of the current collectors 4 and 6 is such that the above-described metal material plate-like member is bent and formed in a posture along the side surface on the short side of the casing BC to have a substantially L shape. A portion extending along the surface of the lid portion 2 that is an arrangement surface of the lid portion, and a vertical posture portion that is bent 90 degrees downward near the longitudinal end portion of the lid portion 2 and extends in the normal direction of the lid portion 2. It has a continuous shape. Bifurcated connecting portions 4a and 6a for connecting to the power generation element 3 are formed by bending the current collectors 4 and 6 to the power generation element 3 side.

  As shown in FIG. 3, the power generating element 3 includes a pair of electrode plates 31, 32 each composed of a foil-like positive electrode plate 31 formed in a long strip shape and a foil-like negative electrode plate 32 formed in a long strip shape. The active material layers 31a and 32a are formed on both front and back surfaces by coating, and the so-called wound-type power generation elements are stacked in a state where the separators 33 are wound in a long strip shape. It is configured as. That is, the electrode plates 31 and 32 and the separator 33 are alternately stacked, and when viewed from the electrode plates 31 and 32, the positive electrode plate 31 and the negative electrode plate 32 are alternately arranged in the stacking direction. Has been placed.

The foil-like positive electrode plate 31 and the like are wound around a flat winding axis, and the wound one has a flat shape in accordance with the shape of the battery casing BC. In FIG. 3, the application area | region of an active material is shown with the double diagonal line.
The foil-shaped positive electrode plate 31 is formed of the same material as the main component of aluminum as the current collector 4, and the foil-shaped negative electrode plate 32 is formed of the same material as the main component of copper as the current collector 6. Has been.
The separator 33 is formed as a resin microporous film.

The active material layers 31a and 32a in the foil-like positive electrode plate 31 and the foil-like negative electrode plate 32 are formed in the active material layers 31a and 32a at the end portions in the horizontal width direction (direction indicated by arrow A in FIG. 3). Narrow band-like regions that are not set are set, and these regions serve as non-formed portions 3 a and 3 b for connection to the current collectors 4 and 6. The unformed portions 3a and 3b are welded to the connecting portions 4a and 6a of the current collectors 4 and 6, and the power generating element 3 and the terminal bolts 5 and 7 are electrically connected.
In the present embodiment, as described above, the active material layers 31a and 32a are applied and formed, and the unformed portions 3a and 3b are referred to as “uncoated” by using a general expression in that case. Part 3a, 3b ".

The uncoated part 3a of the foil-like positive electrode plate 31 and the uncoated part 3b of the foil-like negative electrode plate 32 are located at the opposite end (reverse side) end in the lateral width direction of the foil-like positive electrode plate 31 or the like. In addition, when viewed in the stacking direction, the position where the uncoated portion 3a of the foil-shaped positive plate 31 is present and the position where the uncoated portion 3b of the foil-shaped negative plate 32 is present are set so as not to overlap.
The uncoated portion 3a of the foil-like positive electrode plate 31 extends in the horizontal width direction from the edges of the foil-like negative electrode plate 32 and the separator 33, and the uncoated portion 3b of the foil-like negative electrode plate 32 is a foil-like positive electrode plate. 31 and the edge of the separator 33 extend in the lateral width direction. Therefore, in the state where the foil-like positive electrode plate 31, the foil-like negative electrode plate 32 and the separator 33 are wound, as shown in FIG. 3, the state is distributed to both ends in the winding axis direction extending in the lateral width direction of the separator 33 and the like. The uncoated portions 3a and 3b are located. The length of the separator 33 in the horizontal width direction is set to be slightly wider than the active material application width of the foil-like positive electrode plate 31 and the foil-like negative electrode plate 32, and the foil-like positive electrode plate 31 is not coated. At the end of the part 3a side, it extends in the horizontal width direction from the edge of the foil-like negative electrode plate 32 on which the negative electrode active material layer 32a is formed (see FIG. 5 described later), and the uncoated part 3b of the foil-like negative electrode plate 32 At the side end, it extends in the lateral width direction from the edge of the foil-like positive electrode plate 31 on which the positive electrode active material layer 31a is formed (see FIG. 4 described later).

The separator 33 as a whole has a sheet shape as described above. However, as shown in FIG. 6 which is a cross-sectional view in the lateral width direction, the separator 33 is formed on the front and back sides in the lateral width direction (the direction indicated by arrow A in FIG. 6). A first convex portion 34 and a second convex portion 35 projecting in the stacking direction of the separator 33 and the electrode plates 31 and 32 are formed so as to stand in the normal direction from both sheet surfaces. The first convex portion 34 and the second convex portion 35 are both formed as ridges along the edge of the separator 33, and in the present embodiment in which the separator 33 is in the shape of a long band, It is formed over the entire length in the longitudinal direction.
Projecting from each of the opposing surfaces of the separators 33 adjacent in the stacking direction and having the tips facing each other with a gap of a set interval therebetween is the first convex portion 34, and the separators 33 adjacent in the stacking direction It is the 2nd convex part 35 which protrudes from each opposing surface and the front-end | tips have faced in the state which pinched | interposed the uncoated parts 3a and 3b. There is also a gap at a set interval between the tip of the second convex portion 35 and the uncoated portions 3a and 3b.
That is, the first convex portion 34 is formed at the end where the uncoated portions 3a and 3b do not exist in the electrode plates 31 and 32 sandwiched between the separators 33 adjacent in the stacking direction, and the second convex portion 35 is It forms in the position which overlaps with the location of the uncoated parts 3a and 3b which are the objects to be contacted in the stacking direction.
Thereby, the separator 33 adjacent to the first convex portion 34 in the stacking direction has a positional relationship in which the first convex portion 34 is formed in a state where a gap of a set interval is provided. .
The first convex portion 34 and the second convex portion 35 can be formed by injection molding or a molding method in which heat or pressure in the width direction is applied to the end of the separator 33 to plastically deform it in an upright posture. . Further, if the height of the first and second convex portions 34 and 35 is low, the first convex portion 34 and the second convex portion 35 are thinned by applying pressure in the thickness direction to the region excluding the end portion in the lateral width direction. The convex portion 34 and the second convex portion 35 can be formed.

As shown in FIG. 6, among the separators 33, a separator 33a that is in contact with the active material layer 31a of the foil-like positive electrode plate 31 that is a positive electrode plate on the surface on the winding outer periphery side, and a foil-like negative electrode that is a negative electrode plate The separator 33b that is in contact with the active material layer 32a of the plate 32 on the surface on the winding outer periphery side is different in the arrangement form of the first protrusions 34 and the second protrusions 35.
Regarding the positional relationship between the first convex portion 34 and the second convex portion 35 and the electrode plates 31 and 32, one of the foil-like positive electrode plate 31, the foil-like negative electrode plate 32, and the separator 33 in a state of being laminated by winding. This will be described with reference to FIGS. 4 and 5, which are schematic cross-sectional views in which portions are extracted. FIG. 4 shows the end of the negative electrode on the uncoated portion 3b side in the horizontal width direction, and FIG. 5 shows the end of the positive electrode in the horizontal width direction on the uncoated portion 3a side. is there. In FIG. 4 and FIG. 5, the description of the parallel oblique lines indicating the cross section is omitted for easy understanding of the drawings.

As shown in FIG. 4, at the end of the negative electrode on the uncoated part 3 b side, a pair positioned with a foil-like positive electrode plate 31 (positive electrode plate) having positive electrode active material layers 31 a formed on both front and back surfaces. The separators 33a and 33b extend in the horizontal width direction from the edge in the horizontal width direction of the foil-like positive electrode plate 31, and the first protrusion 34 is formed in a portion extending from the edge. ing.
At the end of the separator 33a on the negative electrode uncoated portion 3b side, a first convex portion 34 (referred to as “first convex portion 34a” for convenience) is formed to protrude on the foil-like positive electrode plate 31 side. A second convex portion 35 (referred to as “second convex portion 35a” for convenience) protrudes from the foil-like negative electrode plate 32 side.
At the end of the separator 33b on the negative electrode uncoated portion 3b side, a first convex portion 34 (referred to as “first convex portion 34b” for convenience) is formed to protrude on the foil-like positive electrode plate 31 side. A second convex portion 35 (referred to as “second convex portion 35b” for convenience) protrudes from the foil-like negative electrode plate 32 side.

The first convex part 34 formed in this way is further enlarged on the negative electrode uncoated part 3b side, as shown in FIG. 7A illustrating a cross section near the end of the foil-like positive electrode plate 31. , The tip of the first protrusion 34a that protrudes from the end of the separator 33a toward the foil-shaped positive electrode plate 31 side, and the tip of the first protrusion 34b that protrudes from the end of the separator 33b to the foil-like positive electrode plate 31 side However, they face each other with a gap of the interval “D1”.
Further, the second convex portion 35 further expands the negative electrode uncoated portion 3b side, and as shown in FIG. 7B illustrating a cross section near the end of the foil-like negative electrode plate 32, the separator 33a The tip of the second convex portion 35a protruding from the end toward the foil-like negative electrode plate 32 side and the tip of the second convex portion 35b protruding from the end of the separator 33b toward the foil-like negative electrode plate 32 side are not negative electrodes. It is opposed across the coating part 3b. The gap between the tip of the second convex portion 35a and the surface of the uncoated portion 3b and the gap between the tip of the second convex portion 35b and the surface of the uncoated portion 3b are set to a distance “D2”. .

On the other hand, the end of the positive electrode on the uncoated portion 3a side is positioned with a foil-shaped negative electrode plate 32 (negative electrode plate) having negative electrode active material layers 32a formed on both front and back surfaces, as shown in FIG. The pair of separators 33a and 33b extend in the horizontal width direction from the edge in the horizontal width direction of the foil-shaped negative electrode plate 32, and the first convex portion 34 is formed in a portion extending from the edge. Is formed.
At the end of the separator 33a on the positive electrode uncoated portion 3a side, a first convex portion 34 (referred to as a “first convex portion 34c” for convenience) is formed to protrude on the foil-like negative electrode plate 32 side. A second convex portion 35 (referred to as a “second convex portion 35 c” for convenience) protrudes from the foil-like positive electrode plate 31 side.
At the end of the separator 33b on the positive electrode uncoated portion 3a side, a first convex portion 34 (referred to as a “first convex portion 34d” for convenience) is formed to protrude on the foil-like negative electrode plate 32 side. A second convex portion 35 (referred to as “second convex portion 35d” for convenience) protrudes from the foil-like positive electrode plate 31 side.

The first convex portion 34 formed in this way has the tip of the first convex portion 34c protruding from the end portion of the separator 33a toward the foil-like negative electrode plate 32 side, and the foil-like negative electrode plate 32 from the end portion of the separator 33b. The tip of the first convex portion 34d that protrudes to the side faces the gap with a set interval. The gap of the set interval is the same as the interval “D1” between the tip of the first protrusion 34a and the tip of the first protrusion 34b at the negative electrode uncoated portion 3b side end.
The second protrusion 35 protrudes from the end of the separator 33a toward the foil-shaped positive electrode plate 31 and the tip of the second protrusion 35c protrudes from the end of the separator 33b toward the foil-shaped positive electrode 31. The tip of the second convex portion 35d is opposed to the positive electrode uncoated portion 3a. The gap between the tip of the second convex portion 35c and the surface of the uncoated portion 3a and the gap between the tip of the second convex portion 35d and the surface of the uncoated portion 3a are end portions on the negative electrode uncoated portion 3b side. The distance “D2” is set similarly to the distance between the second convex portion 35a and the negative electrode uncoated portion 3b surface.
The thickness of the positive electrode active material layer 31a is thicker than the thickness of the negative electrode active material layer 32a, and the height of the first convex portion 34 and the second convex portion 35 is mainly due to the difference in thickness. The difference is occurring.

As described above, the gap between the tips of the first projections 34 is the set interval “D1”, and the tips of the second projections 35 and the surfaces of the uncoated portions 3a and 3b. The gap between the separators 33 is the set interval “D2”, so that the separator 33 has a sufficient passage to the space where the foil-like positive electrode plate 31 and the foil-like negative electrode plate 32 on which the active material layers 31a and 32a are formed exist. Thus, the entry of foreign matter into the power generation element 3 can be prevented, and the passage of the electrolyte solution can be secured by the presence of the passage.
For this reason, the values of “D1” and “D2” are set to the width of the gap that can analyze the foreign matter that has entered the power generation element 3 and prevent the foreign matter from entering.
Specifically, the foreign matter is mostly a copper piece (more strictly, a member piece mainly composed of copper) generated in the ultrasonic welding process of the negative electrode uncoated portion 3b, and is the smallest among them. In consideration of the thickness of the foil pieces separated by the uncoated portions 3a and 3b that fall into the size category, the values of “D1” and “D2” are set to be equal to or less than the thickness of the electrode plates 31 and 32. Yes.
When the thicknesses of the foil-like positive electrode plate 31 and the foil-like negative electrode plate 32 are compared, since the thickness of the foil-like negative electrode plate 32 is generally smaller, the values of “D1” and “D2” are more preferably set. The thickness is preferably set to be equal to or less than the thickness of the foil-like negative electrode plate 32.
Note that the value of “D1” and the value of “D2” may be the same value, but are not necessarily the same.

In the power generation element 3 having the above-described configuration, the uncoated portions 3a and 3b are welded and electrically connected to the connection portions 4a and 6a of the current collectors 4 and 6 by ultrasonic welding.
The current collectors 4 and 6 are fixed to the lid portion 2 together with the terminal bolts 5 and 7, the positive terminal bolt 5 is electrically connected to the positive current collector 4, and the negative terminal bolt 7. Is electrically connected to the current collector 6 on the negative electrode side.
The current collector 4 on the positive electrode side is electrically connected to the terminal bolt 5 via a rivet 8 integrally formed on the head side of the terminal bolt 5, and the rivet 8 includes the current collector 4, the current collector 4, and the current collector 4. Lower gasket 12 for electrical insulation between rivet 8 and lid 2, upper gasket 11 for electrical insulation between lid 2 and terminal bolt 5 including lid 2 and rivet 8 and lid 2 In this state, the current collector 4 is caulked at the inner end portion of the casing BC, thereby fixing the current collector 4 to the lid portion 2.
The negative electrode side has the same configuration, and the negative electrode side current collector 6 is electrically connected to the terminal bolt 7 via a rivet 15 integrally formed on the head side of the terminal bolt 7. The electrical current between the terminal 6 including the electrical current 6, the current collector 6 and the lower gasket 18 for electrical insulation between the rivet 15 and the lid 2, the lid 2 and the rivet 15 and the lid 2 The current collector 6 is fixed to the lid portion 2 by being caulked at the inner end of the casing BC in a state of passing through the upper gasket 17 for insulation.

In a state where the power generation element 3 or the like is assembled on the lid portion 2 side in this way, the power generation element 3 or the like is inserted into the can body 1 and the edge of the lid portion 2 and the open end of the can body 1 are welded. Further, an electrolytic solution is injected into the casing BC.
At this time, a gap is provided between the tips of the first protrusions 34 of the separator 33, and further, a gap is provided between the second protrusions 35 of the separator 33 and the uncoated portions 3a and 3b. The electrolyte smoothly enters the power generation element 3.

[Another embodiment]
Hereinafter, other embodiments of the present invention will be listed.
(1) In the above-described embodiment, the first and second convex portions 34 and 35 of the separator 33 have both front and back sheet surfaces at the end in the lateral width direction (the direction indicated by arrow A in FIG. 3 and the like). Although it is formed so as to stand up in the normal direction from each, it may be formed so as to protrude only on one of the front and back sides of the sheet surface.
Corresponding to FIG. 4, the end of the negative electrode uncoated portion 3 b side in the lateral width direction is shown in a laminated sectional view, and corresponding to FIG. 8 and FIG. 5, the positive uncoated portion 3 a in the lateral width direction. 9 and FIG. 6 illustrating the end portion on the side in a laminated sectional view, and FIG. 10 illustrating the sectional view of the separator 33 in the lateral width direction, which will be described in more detail. The configuration other than the configuration of the separator 33 is the same as that of the above embodiment.

8 and 9 are compared with FIG. 4 and FIG. 5 of the above embodiment, the separator 33a that contacts the positive electrode active material layer 31a on the winding outer peripheral side, and the positive electrode on the winding inner peripheral side The separator 33b that is in contact with the active material layer 31a has a first protrusion 34 that protrudes in an upright posture from the sheet surface in the stacking direction only on the surface facing the foil-like positive electrode plate 31 that is a positive electrode plate. And the 2nd convex part 35 is formed.
That is, in the separator 33a, the first convex portion 34e corresponding to the first convex portion 34a in the above embodiment, and the second convex portion 35e corresponding to the second convex portion 35c in the above embodiment. In the separator 33b, the first convex portion 34f corresponding to the first convex portion 34b in the above embodiment and the second convex portion corresponding to the second convex portion 35d in the above embodiment are formed. Only the portion 35f is formed. The shapes and arrangement positions of the first and second convex portions 34 and 35 are the same as those in the above embodiment.

As shown in FIG. 8 and FIG. 11 (b) illustrating an enlarged cross-sectional view of the vicinity of the end portion of the foil-like positive electrode plate 31 on the negative electrode uncoated portion 3b side, the end portion on the uncoated portion 3b side of the negative electrode , A pair of separators 33a and 33b positioned in a state of sandwiching a foil-like positive electrode plate 31 (positive electrode plate) having a positive electrode active material layer 31a formed on both the front and back surfaces are foils at the ends of the separators 33a and 33b. The distance between the tips of the first projections 34 protruding toward the positive electrode plate 31 side, that is, the tips of the first projection 34e of the separator 33a and the first projection 34f of the separator 33b is "D1". It is in a state of facing each other with a gap.
In addition, the pair of separators 33a and 33b positioned in a state of sandwiching the foil-like negative electrode plate 32 (negative electrode plate) having the negative electrode active material layer 32a formed on both the front and back surfaces, the end portions in the horizontal width direction of the negative electrode active material layer 32a. Open without covering.

On the other hand, at the end of the positive electrode uncoated portion 3a side, as shown in FIG. 9 and FIG. 11 (a) illustrating a further enlarged cross-sectional view of the vicinity of the base end portion of the positive electrode uncoated portion 3a, the positive electrode The pair of separators 33a and 33b positioned with the foil-like positive electrode plate 31 (positive electrode plate) having the active material layer 31a formed on both the front and back surfaces is sandwiched between the foil-like positive electrode plate 31 at the ends of the separators 33a and 33b. Each of the leading ends of the second convex portions 35 protruding to the side, that is, the leading end of the second convex portion 35e of the separator 33a and the leading end of the second convex portion 35f of the separator 33b, and the uncoated portion 3a A gap having a distance “D2” is formed between the surface and the surface.
The values of the interval “D1” and the interval “D2” may be the same as those in the above embodiment.
In addition, the pair of separators 33a and 33b positioned in a state of sandwiching the foil-like negative electrode plate 32 (negative electrode plate) having the negative electrode active material layer 32a formed on both the front and back surfaces, the end portions in the horizontal width direction of the negative electrode active material layer 32a. Open without covering.

As for the phenomenon that a foreign material penetrate | invades in the electric power generation element 3 and a short circuit failure occurs, the foreign material has almost penetrated into the existence space of the foil-like positive electrode plate 31 on which the positive electrode active material layer 31a is formed. Even if the first convex portion 34 and the second convex portion 35 are configured to protrude only to the foil-like positive electrode plate 31 side, it is possible to sufficiently prevent the entry of foreign matter that causes a short-circuit failure.
Thus, the manufacturing process of the separator 33 can be simplified by forming the first protrusion 34 and the second protrusion 35 so as to protrude from the sheet surface of the separator 33 only to one side.

(2) In the above embodiment, the pair of separators 33a and 33b positioned in a state where the foil-like positive electrode plate 31 and the foil-like negative electrode plate 32 are sandwiched between the pair of separators 33a and 33b project from both of the first convex portions 34. Although the tips are in contact with each other, the first convex portion 34 is formed only on one of the pair of separators 33a and 33b, and the tip of the first convex portion 34 and the counterpart separator 33 are formed. It is good also as a structure which has the clearance gap of the above-mentioned space | interval "D1" between sheet surfaces.
(3) In the above embodiment, the winding type power generating element 3 in which a long belt-like electrode plate or separator is wound and laminated is illustrated, but a simple sheet-like positive and negative electrode plate and separator, The present invention can also be applied to a power generation element of a type in which a plurality of layers are alternately stacked.
(4) In the above embodiment, the non-aqueous electrolyte secondary battery RB is described as an example of the power storage device, but the present invention can be applied to various power storage devices such as capacitors.

3 Power storage elements 31, 32 Electrode plates 31a, 32a Active material layer 33 Separator 34 First convex portion 35 Second convex portion

Claims (6)

Electrode plates having active material layers formed on the surfaces and sheet-like separators are alternately stacked and arranged, and the separator extends at one end of the electrode plate from the edge of the electrode plate. A power storage device comprising:
In the power storage element,
A first protrusion that protrudes in the stacking direction is formed on a portion that extends beyond the edge of the electrode plate in the separator,
A power storage device in which the first convex portion and a separator adjacent in the stacking direction are arranged at a position where the first convex portion is formed, with a gap therebetween. The first convex portion is formed on each of the opposing surfaces of the separators adjacent in the stacking direction,
The power storage device according to claim 1, wherein the gap is formed between the first convex portions that are formed to protrude from the respective separators. The electrode plate is arranged in a state in which positive electrode plates and negative electrode plates are alternately arranged in the stacking direction,
The power storage device according to claim 1, wherein the first protrusion is formed only on a surface facing the positive electrode plate. The electrode plate is arranged in a state in which positive electrode plates and negative electrode plates are alternately arranged in the stacking direction,
An unformed part that does not form the active material layer is set at one end of the electrode plate,
The non-formed part of the positive electrode plate and the non-formed part of the negative electrode plate are arranged at positions that do not overlap with each other in the stacking direction in a state of extending from an edge of the separator,
The first convex portion is formed at an end portion where the unformed portion does not exist in the electrode plate sandwiched between separators adjacent in the stacking direction,
2nd convex part which protrudes in the said lamination direction and has a clearance gap between said non-formation parts is formed in the said separator in the position which overlaps with the location where the said non-formation part exists in the said lamination direction. Item 3. The power storage device according to item 1 or 2.   The power storage device according to claim 4, wherein the first protrusion and the second protrusion are formed only on a surface facing the electrode plate of the positive electrode. The electrode plate and the separator are formed in a long band shape,
The first convex portion is formed in a portion extending in a lateral width direction from an edge of the electrode plate in the separator,
The power storage device according to any one of claims 1 to 5, wherein the long belt-like electrode plate and the separator are wound around a winding axis extending in the lateral width direction.

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