JP2014199780A - Electricity storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a longer life of an electricity storage element by using an electrolyte in a housing container without waste.SOLUTION: A nonaqueous electrolyte secondary battery 1 includes: an electrode body 11; an electrolyte; a housing container housing the electrode body 11 and the electrolyte and comprising a lid part 20 and a container body 10; and an interposed body 12 disposed between the housing container and the electrode body 11. The interposed body 12 is provided with an exposed surface 12a1 as a first region which has insulation properties and permeability to the electrolyte.

Description

  The present invention relates to power storage elements such as secondary batteries and other batteries.

  Secondary batteries are widely used as power sources for electronic devices such as mobile phones and IT devices, as well as for replacing primary batteries. In particular, a non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery has a high energy density, and is therefore being applied to industrial large electric devices such as electric vehicles.

  Non-aqueous electrolyte secondary batteries generally contain an electrode body and an electrolytic solution formed by laminating or winding positive and negative electrode plates separated by a microporous membrane separator inside a conductive metal container. (See, for example, Patent Document 1 and FIG. 1). Such non-aqueous electrolyte secondary batteries are being modularized by arranging a plurality of batteries in order to obtain high output and large capacity.

Japanese Patent No. 4296522

  Such conventional non-aqueous electrolyte secondary batteries have the following problems. That is, in order to prevent a short circuit due to contact with the inner wall of the storage container, the electrode body is stored in the storage container in a state where the surface thereof is covered with an intervening body made of an insulating film.

  However, the electrolytic solution filled in the storage container is separated from the electrode body by the insulating film, and there is an electrolytic solution that cannot participate in the battery reaction in the electrode body. In particular, in the inner bottom of the storage container, the electrolytic solution isolated by the insulating film sometimes stays without contributing to the battery reaction.

  Thus, in the electrical storage element including the conventional nonaqueous electrolyte secondary battery, there existed a subject that the electrolyte solution in a storage container was not used effectively.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power storage device that improves the utilization efficiency of an electrolytic solution in a storage container for a battery reaction.

In order to achieve the above object, the first aspect of the present invention provides:
An electrode body;
An electrolyte,
A storage container for storing the electrode body and the electrolyte; and
An interposed body disposed between the storage container and the electrode body,
In the intervention body,
A first region having insulation and permeability to the electrolyte is provided;
It is a power storage element.

The second aspect of the present invention is
The intervening body is provided with a second region that is impermeable to the electrolytic solution.
It is an electrical storage element of the 1st side surface of this invention.

The third aspect of the present invention is
The first region of the interposer faces the inner bottom of the storage container;
It is an electrical storage element of the 1st or 2nd side surface of this invention.

The fourth aspect of the present invention is
The first region of the interposition body is located at a place where the distance between the inner wall of the storage container and the electrode body is the largest,
It is an electrical storage element of the 1st to 3rd side surface of this invention.

The fifth aspect of the present invention provides
The first region of the interposer faces an inner wall corresponding to a surface on which the storage container is placed;
It is an electrical storage element of any one of the 1st to 4th side of the present invention.

The sixth aspect of the present invention provides
The first region of the interposer has a deflection or a heel;
It is an electrical storage element of the 1st to 5th side surface of this invention.

  The present invention as described above has an effect that it is possible to increase the utilization efficiency of the electrolytic solution in the storage container for the battery reaction in the power storage element and to obtain a long life.

1 is an exploded perspective view showing a configuration of a nonaqueous electrolyte secondary battery according to Embodiment 1 of the present invention. The front view which shows the structure of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention. The side view which shows the structure of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention. (A) The figure for demonstrating the manufacturing process of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention (b) The manufacturing process of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention is demonstrated. Illustration to do The figure for demonstrating the effect of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention The side view which shows the other structural example of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention. The principal part perspective view which shows the structure of the nonaqueous electrolyte secondary battery which concerns on Embodiment 2 of this invention. The side view which shows the structure of the nonaqueous electrolyte secondary battery which concerns on Embodiment 2 of this invention. The principal part perspective view which shows the other structural example of the nonaqueous electrolyte secondary battery of this invention. The principal part perspective view which shows the other structural example of the nonaqueous electrolyte secondary battery of this invention. The side view which shows the other structural example of the nonaqueous electrolyte secondary battery which concerns on Embodiment 1 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view schematically showing a configuration of a nonaqueous electrolyte secondary battery 1 according to Embodiment 1 of the present invention in a partially disassembled state, and FIG. 2 is a nonaqueous electrolyte secondary battery 1. FIG. 3 is a side view of FIG.

  As shown in each drawing of FIGS. 1 to 3, the nonaqueous electrolyte secondary battery 1 is made of the same material as the container main body, which seals the opening box-shaped container main body 10 made of aluminum and the opening 10 x of the container main body 10. An outer hexahedron-shaped storage container composed of a plate-shaped lid portion 20 made of metal is provided as an exterior. In addition, in order to demonstrate the internal structure of the nonaqueous electrolyte battery 1, the container main body 10 showed the outline with the broken line in FIG. 1, and showed the principal part as a perspective view. For the same reason, the container body 10 is shown in FIG. 2 as a cross-sectional view taken along a plane parallel to the long side surface of the container body 10 itself, and in FIG. 3, it is parallel to the short side surface of the container body 10 itself. It was shown as a cross-sectional view cut along a plane.

  In the internal space 10z of the container body 10, an electrode body 11 having a configuration in which a positive electrode and a negative electrode, which are band-shaped electrodes, are wound in a long cylindrical shape with a separator interposed therebetween is disposed. In FIG. 1, for the sake of explanation, the electrode body 11 is shown in a state where it is combined with the lid portion 20 and is partially extracted from the container body 10.

  In the electrode body 11, positive and negative metal foils are exposed at both ends of the winding shaft with the separator 11 a 1 exposed at the outermost periphery in between, and a pair of short side surfaces of the container body 10 are exposed as metal foil exposed portions. Each is located. In the figure, only the configuration in the vicinity of the positive electrode-side metal foil exposed portion 11a2 that is the metal foil on the positive electrode side is described with reference numerals, but the same applies to the negative electrode side.

  The positive side metal foil exposed part 11a2 is connected to a current collector 11a3 fixed to the lid part 20, and the current collector 11a3 and the positive side metal foil exposed part 11a2 are sandwiched and welded by a thin metal plate sandwiching plate 11a4. Fixed. The current collector 11a3 is electrically and mechanically connected to a metal relay plate 22 located on the lid 20 by a known technical means such as caulking or crimping. Further, the relay plate 22 is for external connection. The electrode terminal 23 is electrically connected. Thereby, electricity is taken out from the electrode body 11 to the outside of the storage container.

  The conductive path connecting the electrode terminal 23 and the electrode body 11 is insulated from the storage container by a synthetic resin packing 21 which is an insulator. The packing 21 also serves to seal the space and gap between the conductive path and the storage container in order to prevent leakage of the electrolyte from the inside of the storage container.

  Next, the side surfaces and the bottom surface of the electrode body 11 that are opposed to the inner wall including the inner bottom 10y of the container body 10 are covered with an interposer 12 composed of insulating coating films 12a and 12b. ing. That is, between the side surface and bottom surface of the electrode body 11 and the inner surface of the container body 10, the interposition body 12 for insulating the electrode body 11 and the container body 10 is disposed. For convenience of showing the electrode body 11 and the like, in FIG. 2, only the outline of the covering film 12 a is shown by a one-dot chain line. Similarly, only the outline of the covering film 12b is indicated by a dotted line. In FIG. 3, the covering films 12 a and 12 b are shown as cross-sectional views of the interposition body 12.

  Each of the covering films 12a and 12b has a belt-like outer shape, and as schematically shown in FIGS. 4 (a) and 4 (b), the covering film 12a extends the electrode body 11 along the winding direction thereof. 10 wraps the main surface corresponding to the front and back surfaces of 10 and the bottom surface facing the inner bottom 10y, and then the covering film 12b is drawn to the side surface of the electrode body 11 together with the covering film 12a, whereby the interposer 12 is completed. To do. In the present embodiment, the boundary 12b1 between the covering films 12a and 12b shown in FIG. 3 is brought into close contact, whereby the interposer 12 is integrated and formed into a bag shape having an opening 12x. However, a gap may be formed between the covering film 12a and the covering film 12b without bringing the boundary 12b1 into close contact.

  In FIG. 4A, the constituent elements other than the covering film 12a are indicated by dotted lines for convenience of explanation. Similarly, in FIG. 4B, components other than the covering film 12b are indicated by dotted lines.

  The lid portion 20 is provided with an inlet 24x for injecting an electrolytic solution after the container body 10 is sealed by laser welding or the like. After the electrolytic solution is injected, the lid portion 20 is sealed by a sealing plug 24. The nonaqueous electrolyte secondary battery 1 is completed by welding the periphery of the sealing plug 24x by laser welding or the like.

  In the above configuration, the non-aqueous electrolyte secondary battery 1 corresponds to the electricity storage element of the present invention, the combination of the container body 10 and the lid 20 corresponds to the storage container of the present invention, and the container body 10 corresponds to the container body of the present invention. The lid portion 20 corresponds to the lid portion of the present invention. The intervention body 12 corresponds to the intervention body of the present invention.

  In the nonaqueous electrolyte secondary battery 1 according to the present embodiment having such a configuration, the covering film 12a having a surface facing the inner bottom 10y of the container body 10 in the interposer 12 is permeable to the electrolytic solution. It is characterized by that.

  That is, in the conventional non-aqueous electrolyte secondary battery, the electrode body is covered with the interposition body in order to ensure the insulation state with the storage container, but the electrode body is interposed in the storage container through the interposition body. In this state, the electrolyte solution was impregnated, and a part of the electrolyte solution stayed in the storage container in a state where it was shielded from the electrode body by the intervening body and could not participate in the battery reaction.

  In contrast, in the present embodiment, the interposition body 12 is configured as a combination of two covering films 12a and 12b, and the covering film 12b is drawn around the side surface of the electrode body 11 and faces the side surface portion of the container body. Is made of an insulating synthetic resin film such as polyethylene and polypropylene as in the conventional example, while the covering film 12a exposed to face the inner bottom 10y of the container body 10 and the inner wall 10a in the longitudinal direction has an insulating property. It is made of a porous synthetic resin film, woven fabric or non-woven fabric having permeability and absorbability to the electrolyte.

  Thereby, as shown in the schematic perspective views of FIG. 3 and FIG. 5, the electrolytic solution staying in the internal space 10z1 in the vicinity of the inner bottom 10y of the container body 10 travels to the electrode body 11 side through the coating film 12a. It becomes possible to do. Thereby, the electrolyte solution of the outer side of the interposed body 12 can be introduce | transduced into the inner side of the interposed body 12, and the utilization efficiency for the battery reaction of the electrolyte solution in a storage container can be improved. Further, it is possible to extend the life of the nonaqueous electrolyte secondary battery 1 by increasing the utilization efficiency of the electrolytic solution. Here, the exposed surface 12a1 of the covering film 12a corresponds to the first region of the present invention, and the portion where the covering film 12a and the covering film 12b overlap and the portion where the covering film 12b is exposed alone are the second portion of the present invention. It corresponds to the area.

  In the above description, the exposed surface 12a1 is provided to face the inner bottom 10y and the inner wall 10a of the container body 10, but the side facing the inner bottom 10y of the container body 10 is omitted. You may make it provide only in the side facing the inner wall 10a of the container main body 10. FIG.

  This is based on the following reason. That is, as shown in FIGS. 1 to 3 and the like, when the nonaqueous electrolyte secondary battery 1 is used with the lid portion 20 facing vertically upward and the bottom surface of the container body 10 as a mounting surface, in the internal space 10z of the storage container, The electrolytic solution always fills the internal space 10z1 in the vicinity of the inner bottom 10y of the container body 10, but when viewed locally, the location where the ratio of the electrolytic solution staying in the internal space 10z1 of the storage container is maximized is Due to the outer shape of the electrode body 11 having an oval cross section perpendicular to the winding axis, the distance between the container body 10 and the electrode body 11 is maximized. It is between the corners 10b, and is conversely smaller at the part facing the inner bottom 10y.

  Therefore, the exposed surface 12a1 may be formed only on the surface facing the corner 10b of the container main body, in which the ratio of the electrolytic solution in the internal space 10z1 is maximized. Can be introduced into the electrode body 11.

  In short, the first region of the present invention may be provided at any location in the storage container as long as the distance between the electrode body and the inner wall of the storage container is maximized. The electrolyte solution can be directly and promptly introduced without depending on the shape of the storage container and the electrode body. However, the inner bottom 10y of the rectangular parallelepiped container main body 10 is a place where the electrolytic solution is likely to stay, and in order to ensure the utilization efficiency of the electrolytic solution, the first region is positioned on the surface facing this. Is preferred.

  In the above description, the nonaqueous electrolyte secondary battery 1 is used in a state where the bottom surface of the container body 10 is placed, and the exposed surface 12a1 is provided facing the inner bottom 10y which is the back surface of the bottom surface. However, as shown in FIG. 11, the container body 10 may be provided to face the inner wall 10 w 1 in the longitudinal direction. In this configuration, the non-electrolyte secondary battery is used so as to fall sideways with the side surface 10w2 that is the outside of the inner wall 10w1 of the container body 10 as the mounting surface according to the arrow D in the drawing that indicates the vertically downward direction. In this case, the electrolytic solution always fills the inner space 10z3 in the vicinity of the inner wall 10w1 in the inner space 10z of the storage container, and is introduced to the electrode body 11 side through the exposed surface 12a1 facing the inner wall 10w1.

  Thus, if the first region of the present invention is a location facing the inner wall corresponding to the back surface of the surface to be the placement surface of the storage container in the usage state of the nonaqueous electrolyte secondary battery as the power storage element, You may make it provide in arbitrary places. The first region is surely positioned in the space always filled with the electrolytic solution, and the electrolytic solution can be introduced into the electrode body.

  In the above description, the exposed surface 12a1 of the covering film 12a is described as a uniform surface, but the surface may be wrinkled, shrunk, or bent. In this case, the absorption area of the electrolytic solution on the exposed surface 12a1 increases, and the electrolytic solution staying in the internal space 10z can be further aggregated on the internal space 10z1 side, thereby increasing the utilization efficiency of the electrolytic solution.

  Furthermore, as a modified example of the exposed surface 12a1, as shown in a schematic perspective view of FIG. 6, the exposed surface 12c1 having a plurality of convex lines 121 extending substantially parallel to the long side of the inner bottom 10y. It is good. The convex 121 is formed by bending the coating film 12a1 into a bellows shape.

  As shown in FIG. 1 and FIG. 2, the injection port 24 is located substantially at the center of the exposed surface 12 c 1 when viewed from the lid part 20, so that the electrolyte injected from the lid part 20 extends along the convex lines 121. Thus, the electrolyte solution can be smoothly and uniformly injected into the storage container. Further, the convex 121 functions as a buffer material between the inner bottom 10y and the electrode body 11, and has an effect of preventing the electrode body 11 from contacting the inner bottom 10y due to an impact on the nonaqueous electrolyte secondary battery.

(Embodiment 2)
The nonaqueous electrolyte secondary battery according to Embodiment 2 of the present invention has an interposer made of a single film material.

  FIG. 7 shows a configuration in which the electrode body 11 is covered with an interposer 13 formed by forming a single covering film in a bag shape in a nonaqueous electrolyte secondary battery, and the side surface of the electrode body 11 is covered. And a bottom surface coating 13a that covers the side facing the bottom surface 10y of the container body 10 in a state of being stored in the storage container. In the figure, the container body 10 is omitted.

  As shown in the cross-sectional view orthogonal to the winding axis of the electrode body 11 in FIG. 8, the intermediate body 13b1 has the same insulating property as the coating film 12a, and permeability and absorbability for the electrolytic solution. And a laminated film composed of a surface layer 13b2 having the same insulating properties and imperviousness to the electrolytic solution as the covering film 12b, which are bonded to both surfaces of the intermediate layer 13b1.

  The bottom surface coating 13a is formed by removing the surface layer 13b2 from the laminated film and only the intermediate layer 13b1, and the side surface coating 13b is formed by an unprocessed laminated film, that is, the intermediate layer 13b1 and the pair of surface layers 13b2. It is a thing. Here, the bottom surface coating 13a corresponds to the first region of the present invention, and the side surface coating 13b corresponds to the second region of the present invention.

  According to the present embodiment, in addition to the effects of the first embodiment, the following effects are further obtained. That is, the thickness of the film can be reduced compared to the first embodiment using a plurality of individual coating films, and the storage capacity of the electrolytic solution can be increased by increasing the tolerance of the storage container. . Further, when the electrode body 11 is incorporated into the container body 10, it is possible to suppress damage or peeling from the electrode body 11 due to the coating film coming into contact with the opening 10 x.

  In the above description, the intervening body 13 is described as having a three-layer structure of the intermediate layer b1 and the surface layer b2 bonded to both surfaces of the intermediate layer b1, but has only one surface layer b2. A two-layer structure may be used. At this time, the surface layer 13b2 may be provided on either the side facing the electrode body 11 or the side facing the inner wall of the container body 10. However, the container body 10 is taken into consideration that the coating film is in contact with the opening 10x. It is preferable to provide it on the side facing the inner wall.

  Further, in the laminated film, a layer having insulation properties and permeability to electrolyte solution, such as the intermediate layer 13b1, and a layer having insulation properties and impermeable properties to the electrolyte solution, such as the surface layer 13b2, are defined after completion. Any number of layers may be used as long as the first region of the present invention is formed in the intermediate body.

  As described above, according to the non-aqueous electrolyte secondary battery of each embodiment of the present invention, a part of the coating film that covers the electrode body is made to be permeable to the electrolytic solution, so that the storage container The electrolytic solution staying in the internal space 10z1 can be made to travel to the electrode body 11 side through the bottom surface coating 13a, so that the utilization efficiency of the electrolytic solution in the storage container for the battery reaction in the electrode body 11 can be increased. Can be increased. Furthermore, the lifetime of the non-aqueous electrolyte secondary battery 1 can be increased.

  However, the present invention is not limited to the above embodiment.

  In the above embodiment, the intervention body of the present invention has the first region having permeability to the electrolytic solution and the second region having impermeability to the electrolytic solution. It is good also as what has only 1 area | region.

  In the configuration example shown in FIG. 9, the saddle-shaped intercalation body 14 that mainly covers the facing surfaces of the positive and negative current collectors and the sandwiching plate and the inner bottom 10 y of the electrode body 11 is the same as the covering film 12 a. It is made of a porous synthetic resin film, woven fabric or non-woven fabric having insulating properties, permeability to electrolyte solution, and absorbability. Therefore, the interposer 14 can cause the electrolyte solution to travel to the electrode body 11 side through all the wall surfaces including the bottom surface coating 14 a that is the surface facing the bottom surface 10 y of the container body 10. In addition, the interposition body 14 may be formed in a bowl shape by combining a plurality of films, or may be configured from a single film. In FIG. 9, components other than the interposition body 14 are indicated by dotted lines for convenience of explanation.

  Further, the shape of the interposer may be a bag shape shown in the first and second embodiments in addition to the bag shape shown in FIG. Furthermore, the intervention body shown in the first and second embodiments may be the same shape as the intervention body 14.

  In the above description, the electrode body of the present invention is a wound type, but may be a stacked type electrode body.

  Furthermore, in the above description, the electrode body is a single body, but may have a structure having a plurality of electrode bodies. FIG. 10 shows, as an example, a configuration in which the first embodiment is applied to the nonaqueous electrolyte secondary battery provided in the electrode bodies 11a and 11b arranged in parallel with the winding shaft.

  In particular, when a wound electrode body is used, the cross-sectional shape orthogonal to the winding axis is deformed into an ellipse or an ellipse, and the distance from the inner wall of the storage container is not uniform. Further, in order to easily and safely incorporate the electrode body into the container body 10, in particular, when the shape of the intervention body is made to follow the electrode body with high accuracy, in particular, the internal space that is the gap between the electrode bodies 11 a and 11 b As shown in the space 10z3, as the number of electrode bodies accommodated in the storage container increases, the amount of the electrolyte solution enclosed in the intervention body and used for the battery reaction may decrease.

  With respect to the configuration of such an electrode body, as in the present invention, the side facing the inner bottom 10y of the storage container of the interposer is formed as an exposed surface 12a1 having permeability to the electrolytic solution, and the storage container side By replenishing the electrolyte solution, the utilization efficiency of the electrolyte solution for the battery reaction can be increased, and further, the battery life can be extended.

  In the above description, the storage element of the present invention is the non-aqueous electrolyte secondary battery 1 typified by a lithium ion secondary battery. However, if the battery can be charged and discharged by an electrochemical reaction, Nickel metal hydride batteries and other various secondary batteries may be used. Moreover, a primary battery may be sufficient. In short, the power storage element of the present invention is not limited by a specific method for generating electromotive force as long as it is an element capable of accumulating electricity formed by sealing an electrode body and an electrolyte in a storage container. .

In the above description, the storage container composed of the container main body 10 and the lid 20 corresponds to the storage container of the present invention, and the electrode body 11 is connected to the lid 20 and the electrode terminal 23 and the like. However, in the present invention, it is only necessary that the intervening body is positioned between the electrode body and the storage container, and the storage container is a specific example of the combination of the cover part and the container body. It is not limited to the specific embodiment.

  Although the container body 10 is made of aluminum, it may be made of an aluminum alloy, stainless steel or any other metal or metal compound, resin, or aluminum laminate. Moreover, although the shape is an external hexahedron, it may be a prismatic shape whose bottom surface is a triangle or a polygon more than a pentagon. Furthermore, a cylindrical shape may be sufficient.

  Further, in the above description, the single nonaqueous electrolyte secondary battery 1 is taken as an example, but the present invention is a power supply comprising a power storage element of the present invention in at least one power storage element among a plurality of power storage elements. It may be realized as a module.

  In short, the present invention may be implemented by adding various modifications to the above-described embodiment, including those described above, as long as they do not depart from the spirit of the present invention.

  The present invention as described above has the effect of making it possible to increase the utilization efficiency of the electrolytic solution in the storage container for the battery reaction in the power storage element, and is useful in the power storage element such as a secondary battery. .

DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery 10 Container main body 10a Side wall 10b Corner 10x Opening 10y Bottom surface 10z Internal space 10z1 Internal space 11, 11a, 11b Electrode body 11a1 Separator 11a2 Electrode 11a3 Current collector 11a4 Holding plate 11R Side edge 10z1 Space | gap 12,13 , 14 Interposer 12a, 12b Cover film 12a1 Exposed surface 21 Packing 22 Relay plate 23 Electrode terminal 24 Inlet 25 Sealing plug

Claims (6)

An electrode body;
An electrolyte,
A storage container for storing the electrode body and the electrolyte; and
An interposed body disposed between the storage container and the electrode body,
In the intervention body,
A first region having insulation and permeability to the electrolyte is provided;
Power storage element. The intervening body is provided with a second region that is impermeable to the electrolytic solution.
The electricity storage device according to claim 1. The first region of the interposer faces the inner bottom of the storage container;
The electrical storage element of Claim 1 or 2. The first region of the interposition body is located at a place where the distance between the inner wall of the storage container and the electrode body is the largest,
The electrical storage element in any one of Claim 1 to 3. The first region of the interposer faces an inner wall corresponding to a surface on which the storage container is placed;
The electrical storage element in any one of Claim 1 to 4. The first region of the interposer has a deflection or a heel;
The electrical storage element in any one of Claim 1 to 5.

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