JP6637675B2 - Storage module and battery pack - Google Patents

Description

  The present invention relates to an assembled battery that is lightweight, has high heat dissipation, and saves space.

  In this specification, the term “aluminum” is used to mean Al and an Al alloy, the term “copper” is used to mean Cu and a Cu alloy, and the term “nickel” is Ni and The term "titanium" is used to include Ti and Ti alloys. In this specification, the term “metal” is used to include a single metal and an alloy.

  Lithium ion secondary batteries and lithium polymer secondary batteries used in hybrid and electric vehicle batteries, home or industrial stationary storage batteries have been downsized and lightened. Instead, a laminate exterior material in which a resin film is bonded to both sides of a metal foil is often used. In addition, it has been studied to mount an electric double layer capacitor, a lithium ion capacitor, or the like using a laminate exterior material on an automobile or a bus.

For devices that require high energy, such as electric vehicles, in order to obtain a large amount of electric energy in a small volume, it is necessary to stack power storage modules and connect them in series, but due to the internal resistance of the module when charging and discharging Since heat easily accumulates and the temperature inside the module becomes high, not only acceleration of battery deterioration and deterioration of performance are affected, but also safety is affected. For this reason, in an assembled battery in which a plurality of power storage modules are stacked, it has been proposed to cool the modules by interposing a heat radiating member between the power storage modules (see Patent Documents 1 and 2).
In the battery pack described in Patent Literature 1, a corrugated material is interposed between power storage modules as a heat radiating member to form a cool air circulation space to obtain a heat radiating effect. Further, in the battery pack described in Patent Document 2, a tube member for flowing a cooling liquid is arranged between the power storage modules, and a leaf spring is interposed between the tube member and the power storage module for air cooling. By forming the space, a high cooling effect is obtained by both liquid cooling and air cooling.

JP 2012-84551 A JP 2014-170697 A

  However, the cooling methods described in Patent Literatures 1 and 2 require a bulky heat radiating member such as a corrugated material, a pipe member, and a leaf spring, and further require a supply device of a cool air or a cooling liquid. Cooling system occupies a large space. Therefore, even if the size of the power storage module is reduced, it is difficult to reduce the size of the battery pack.

  The present invention has been made in view of such a technical background, and an object of the present invention is to provide a power storage module and a battery pack with good heat dissipation efficiency.

  That is, the present invention has the configurations described in the following [1] to [5].

[1] A first heat-resistant resin layer is laminated on one surface of the first metal foil, a first thermoplastic resin layer is laminated on the other surface, and a first metal foil is laminated on the surface on the first thermoplastic resin layer side. A first exterior material having a first metal foil inner exposed portion where is exposed,
A second heat-resistant resin layer is laminated on one surface of the second metal foil and a second thermoplastic resin layer is laminated on the other surface, and the second metal foil is exposed on the surface on the second thermoplastic resin layer side. A second exterior material having a second metal foil inner exposed portion,
A positive electrode active material layer stacked on the first metal foil inner exposed portion, a negative electrode active material layer stacked on the second metal foil inner exposed portion, and a battery element having a separator disposed therebetween. ,
At least one of the first exterior material and the second exterior material has an embossed portion in a region including the first metal foil inside exposed portion and the second metal foil inside exposed portion, and the first exterior material has a first embossed portion. By facing the thermoplastic resin layer and the second thermoplastic resin layer of the second exterior material and being surrounded by the heat sealing portion where the first thermoplastic resin layer and the second thermoplastic resin layer are fused, An exterior body having one or more battery element chambers facing the first metal foil inner exposed portion and the second metal foil inner exposed portion, and having an outer surface having irregularities by the embossed portion is formed,
In the battery element sealed together with the electrolyte in the battery element chamber, the positive electrode active material layer is electrically connected to the first metal foil inside exposed portion, and the negative electrode active material layer is electrically connected to the second metal foil inside exposed portion. Power storage module.

  [2] The method according to the above item 1, wherein at least one of the first metal foil outer exposed portion where the first metal foil is exposed and the second metal foil outer exposed portion where the second metal foil is exposed is formed on the outer surface of the exterior body. The power storage module as described in the above.

  [3] Two or more power storage modules described in 1 or 2 above, the power storage modules are stacked in such a manner that a space is formed between adjacent power storage modules by the uneven surface of the exterior body, and An assembled battery, wherein the power storage modules are connected in series.

  [4] The assembled battery according to the above item 3, wherein a plurality of power storage modules are stacked such that the battery element chamber and the heat sealing portion overlap in the stacking direction of the power storage modules.

  [5] The battery pack according to the above item 3 or 4, wherein the heat transfer body is arranged between the power storage modules adjacent in the stacking direction.

  In the power storage module according to the above [1], the first metal foil of the first exterior material and the second metal foil of the second exterior material are electrodes of a battery, and the positive electrode active material layer of the battery element is inside the first metal foil. This is a thin module where the negative electrode active material layer is laminated on the exposed part and the negative electrode active material layer is laminated on the exposed part inside the second metal foil. Is good. Since the heat generated by the module is efficiently dissipated, a decrease in battery performance can be suppressed.

  In the power storage module according to the above [2], since the first metal foil outer exposed portion and the second metal foil outer exposed portion are provided on the outer surface of the exterior body, there is no need to pull out the tab lead. Therefore, the heat sealing operation becomes easy. In addition, since the first thermoplastic resin layer and the second thermoplastic resin layer are generally fused to each other in a portion in contact with the battery element chamber of the heat-sealed portion, the adhesion is high, and the tab lead is pulled out from the battery element chamber. High sealing performance can be obtained. Furthermore, by not using a tab lead, weight reduction and space saving can be achieved.

  In the battery pack according to the above [3], a space is formed between adjacent modules in the stacking direction due to irregularities on the outer surface of the exterior body of the power storage module. The heat generated by the module is radiated to the space, and the gas flows into the space to promote heat radiation to cool the battery pack. Since the space is formed without using a heat radiating member, a cooling effect can be obtained without increasing the size of the assembled battery.

  In the battery pack according to the above [4], since the distance between the battery element chambers of adjacent modules in the stacking direction is increased and the battery element chambers are dispersed in the battery pack, the heat dissipation efficiency is improved, and the cooling effect is high. Is obtained.

  The battery pack according to the above [5] has a high cooling effect because the heat is discharged to the heat transfer body.

It is a perspective view of one embodiment of a storage module of the present invention. FIG. 1B is a sectional view taken along line 1B-1B in FIG. 1A. It is a perspective view of one embodiment of an assembled battery concerning the present invention. It is 2B-2B sectional view taken on the line in FIG. 2A. It is sectional drawing of other embodiment of the assembled battery concerning this invention. It is sectional drawing of further another embodiment of the assembled battery concerning this invention.

  1A and 1B show an embodiment of a power storage module of the present invention, and FIGS. 2A to 4 show embodiments of an assembled battery using the power storage module.

In the following description, the same reference numerals denote the same items, and redundant description will be omitted. Also, in the first exterior material and the second exterior material constituting the exterior body, when the metal foil is exposed regardless of the exterior material and the formation position, the metal foil is generally referred to as “exposed portion of the metal foil”, and the inside of the battery element chamber is referred to. The exposed portion is generically referred to as a “metal foil inner exposed portion”, and the portion exposed to the outer surface of the exterior body is generically referred to as a “metal foil outer exposed portion”.
[Power storage module]
1A and 1B, the exterior body 30 is composed of the first exterior material 10 and the second exterior material 20, and is divided into 3 rows × 3 rows by heat sealing portions 50 crossing vertically and horizontally. Each of the battery element chambers 40 has a core cell 60 as a battery element and an electrolyte (no symbol) sealed therein.

  The first exterior material 10 is a laminated material in which a first heat-resistant resin layer 12 is laminated on one surface of a first metal foil 11 and a first thermoplastic resin layer 13 is laminated on the other surface. Nine first embossed portions 18 projecting from the surface on the side of the conductive resin layer 12 are formed. On the inner surface of each first embossed portion 18, that is, on the surface on the first thermoplastic resin layer 13 side, the first metal foil inner exposed portion where the first thermoplastic resin layer 13 is removed and the first metal foil 11 is exposed 14 are formed. In addition, one side of the first exterior material 10 is extended from the heat sealing portion 50 and both surfaces are exposed to form a first flange 15 serving as an outer surface of the exterior body 30, and a part of the first thermoplastic resin layer 13 is formed. The first metal foil outer exposed portion 16 from which the first metal foil 11 is removed and removed is formed.

  The second exterior material 20 is a laminated material in which a second heat-resistant resin layer 22 is laminated on one surface of a second metal foil 21 and a second thermoplastic resin layer 23 is laminated on the other surface. Nine second embossed portions 28 projecting from the surface on the side of the plastic resin layer 23 are formed. On the outer surface of each second embossed portion 28, that is, on the surface on the second thermoplastic resin layer 23 side, the second metal foil inner exposed portion where the second thermoplastic resin layer 23 is removed and the second metal foil 21 is exposed. 24 are formed. On the opposite side of the first flange 15, the second exterior material 20 is extended from the heat sealing portion 50 and both surfaces are exposed to form a second flange 25 serving as an outer surface of the exterior body 30. A second metal foil outer exposed portion 26 from which a part of the resin layer 23 is removed to expose the second metal foil 21 is formed.

  The core cell 60 includes a positive electrode active material layer 61, a separator 62, a negative electrode active material layer 63, and layers associated therewith. The positive electrode active material layer 61 is laminated on the first metal foil inside exposed portion 14 of the first exterior material 10 via the binder layer 64, and the negative electrode active material layer 63 is formed on the second metal foil inside exposed portion 24 of the second exterior material 20. Are laminated via a binder layer 65.

  The battery element chamber 40 faces the first thermoplastic resin layer 13 of the first exterior material 10 and the second thermoplastic resin layer 23 of the second exterior material 20 with a separator 62 interposed therebetween. It is formed by fitting the second embossed portion 28 therein and assembling the exterior body 30. The battery element chamber 40 is heat-sealed around the embossed portions 18 and 28 in a state in which the electrolyte is injected, and a heat-sealed portion 50 in which the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 are fused. Is sealed. The battery element chamber 40 is a space occupied by the binder layer 64, the positive electrode active material layer 61, the separator 62, the negative electrode active material layer 63, the binder layer 65, and the electrolyte. The separator 62 needs to have a size that covers at least the openings of the embossed portions 18 and 28 in order to reliably separate the positive electrode active material layer 61 and the negative electrode active material layer 63, and preferably has a size that overlaps the heat sealing portion 50. Preferably it is enlarged. Further, in the power storage module 1 having the plurality of battery element chambers 40 as in the present embodiment, instead of using a separate separator for each battery element chamber 40, the plurality of battery element chambers 40 span the heat sealing portion 50. Can be used. In FIG. 1B, one separator 62 is used for the nine battery element chambers 40, and the separator 62 is also sandwiched in the entire region of the heat sealing portion 50.

  Since the positive electrode active material layer 61 constituting the core cell 60 is laminated on the first metal foil inner exposed portion 14 and the negative electrode active material layer 63 is laminated on the second metal foil inner exposed portion 24, the positive electrode active material layer 61 is formed. , The outer package 30 and the core cell 60 by a process of assembling three members, that is, the first package 10 provided with the negative electrode active material layer 63, and the separator 62. Thus, the power storage module 1 is manufactured in a state where is integrated.

  In the power storage module 1, the first metal foil 11 of the first exterior material 10 serves as a positive electrode, and the second metal foil 21 of the second exterior material 20 serves as a negative electrode. These are separated by a separator 62 in each battery element chamber 40. Have been. The connection between the power storage module 1 and an external device is performed at the first metal foil outside exposed portion 16 and the second metal foil outside exposed portion 26 of the exterior body 30.

  Since the battery element chambers 40 are formed by fitting the embossed portions 18 and 28 in the exterior body 30, each battery element chamber 40 protrudes toward the first exterior material 10 with respect to the heat sealing portion 50. . In the drawing, the battery element chamber 40 protrudes upward, and the heat sealing portion 50 protrudes downward. Since each of the plurality of battery element chambers 40 is surrounded by the heat sealing portion 50 and the battery element chambers 40 and the heat sealing portions 50 are alternately arranged, the cross-sectional shape of the exterior body 30 is such that the convex portions and the concave portions are different. It is formed in a rectangular waveform that is repeated alternately. As described above, the exterior body 30 formed three-dimensionally with irregularities on the outer surface has a larger surface area than that of the flat outer surface, so that the heat radiation efficiency is good, and the heat generated by the module is efficiently dissipated. By radiating the heat satisfactorily, a rise in the temperature of the power storage module 1 is suppressed, and a decrease in battery performance can be suppressed. Although the thickness of the exterior body 30 is increased by providing the embossed portions 18 and 28, the heat radiation performance can be enhanced by a slight increase in dimension corresponding to the height of the embossed portions 18 and 28.

  In the power storage module 1, the function as an electrode of the battery is performed by the first metal foil 11 and the second metal foil 21 which are a part of the exterior body 30. This is the total thickness of the layer 64, the positive electrode active material layer 61, the separator 62, the negative electrode active material layer 63, and the binder layer 65, and can be reduced in thickness. On the other hand, the first metal foil inner exposed portion 14 and the second metal foil inner exposed portion 24 facing the inside of the battery element chamber 40 are portions where the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 are removed, respectively. Therefore, when the two exterior materials 10 and 20 face each other, a space for these two layers is generated. Since the separator 62 is a layer sandwiched between the heat sealing portions 50, the thickness of the first thermoplastic resin layer 13 and the total thickness of the binder layer 64 and the positive electrode active material layer 61 are substantially the same, and the second thermoplastic resin If the thickness of the layer 23 and the total thickness of the binder layer 65 and the negative electrode active material layer 63 are substantially the same, the battery element chamber 40 will fall within the total thickness of the first exterior material 10 and the second exterior material 20. Also in the power storage module 1 of the illustrated example, since the core cell is housed in the space created by the formation of the first metal foil exposed portion 14 and the second metal foil inner exposed portion 24, the core cell is a flat exterior body having no embossed portion. It can accommodate a core cell. In the present invention, the first exterior material 10 and the second exterior material 20 having the embossed portions 18 and 28 are used in order to form irregularities on the outer surface of the exterior body 30 even when the battery element fits in the thickness of the exterior material. Although the total thickness of the exterior body 30 is increased by forming the embossed portions 18 and 28, the substantial external thickness in the battery element chamber 40 is equal to the total thickness of the two exterior materials, and is thin. As described above, the power storage module 1 has a higher heat radiation property even when the battery element chamber 40 is thin, and furthermore has a good heat radiation efficiency because the surface area of the exterior body 30 is enlarged.

  The height of the embossed portions 18 and 28 can be freely set within a range in which molding is possible. As the height of the embossed portions 18 and 28 increases, the surface area of the exterior body 30 increases, and the heat radiation efficiency improves.

  The present invention does not specify the relationship between the thickness of the first thermoplastic resin layer 13 and the thickness of the positive electrode active material layer 61 and the relationship between the thickness of the second thermoplastic resin layer 23 and the thickness of the negative electrode active material layer 63. Even if the positive electrode active material layer 61 is thicker than the first thermoplastic resin layer 13 and the negative electrode active material layer 63 is thicker than the second thermoplastic resin layer 23, the first metal foil 11 and the second metal Since the foil 21 is included in the thickness of the exterior body 30, it is still a thin module.

  In a thin module in which the substantial external thickness of the battery element chamber is equivalent to the total thickness of the exterior material, if the surface area is to be increased by forming irregularities on the exterior body, the embossed portion of one exterior material will The structure in which the embossed portion of the exterior material is fitted. As described above, the electrode element chamber formed by the fitting of the embossed portion has a higher sealing property than the battery element chamber formed by the flat exterior material, and the fitting structure of the embossed portion enhances the barrier property of the battery element chamber. ing. In the power storage module 1, the embossed portion 28 of the second exterior material 20 is fitted to the embossed portion 18 of the first exterior material 10, but fitting in the opposite direction is also possible. They can be mixed. Note that, as described above, the present invention does not specify the relationship between the thickness of the thermoplastic resin layer of the exterior material and the thickness of the pole active material layer, so that the battery element chamber is formed by the fitting structure of the embossed portion. Is not limited. If the embossed portion is formed on at least one of the two exterior materials, the embossed portion is included in the technical scope of the present invention, and the effect of improving the heat radiation performance by increasing the surface area of the exterior body can be obtained. In a thin module, since the space height required as a battery element chamber is small, if the embossed portion of one of the exterior materials is made higher, it is necessary to form and fit the embossed portion also to the other exterior material. Therefore, the fitting structure of the embossed portion is a preferable form in terms of both improvement of heat dissipation and improvement of barrier property of the battery element chamber.

  The number of battery element chambers in the power storage module of the present invention is not limited. This is because, even in one battery element chamber, if the battery element chamber is formed by the embossed portion, the surface area is larger than that of the flat exterior body. Further, when the battery capacity of the whole module is the same, the module with a plurality of battery element chambers has a larger surface area of the outer package than the module with one battery element chamber, so that the heat radiation efficiency is good.

  In the power storage module of the present invention, it is essential that the first metal foil inner exposed portion 14 and the second metal foil inner exposed portion 24 are provided in the battery element chamber 40. The presence or absence of the one metal foil outer exposed portion 16 and the second metal foil outer exposed portion 26 can be arbitrarily set. Further, the first metal foil outer exposed portion 16 can be formed at an arbitrary position on the outer surface of the first outer packaging material 10, and the second metal foil outer exposed portion 26 can be formed at an arbitrary position on the outer surface of the second outer packaging material 20. . The exposed portion of the metal foil outside can be formed on the surface on the heat resistant resin layer side, and can be formed on the outer surface of the battery element chamber 40 or the heat sealing portion 40 without providing the flanges 15 and 25. In a module having no metal foil exposed portion on the outer surface of the exterior body 30, the first metal foil 11 and / or the second metal foil 21 is exposed at a portion to be a heat sealing portion on the outer peripheral portion of the module, and a tab lead is joined. By drawing the tip to the outside of the exterior body, conduction with an external device can be obtained.

In the power storage module 1 of the present embodiment, since the first metal foil outer exposed portion 16 and the second metal foil outer exposed portion 26 are provided on the outer surface of the exterior body 30, there is no need to pull out the tab lead. Therefore, the heat sealing operation becomes easy. Further, since the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 are generally fused to each other, the heat-sealed portion 50 has a high adhesion and a higher sealing performance than the module from which the tab lead is drawn out. Can be Furthermore, by not using a tab lead, weight reduction and space saving can be achieved.
[Battery pack]
The assembled battery 5 shown in FIGS. 2A and 2B alternately changes the direction of the four power storage modules 1 so that the first flange 15 and the second flange 25 of the adjacent modules in the stacking direction overlap. Of battery element chambers 40 are stacked in an overlapping manner, and these are connected in series. That is, the four power storage modules 1 are exposed to the second metal foil outside exposed portion 26 of the second flange 25 of the uppermost first layer module and the first metal foil outside exposed portion 26 of the first flange 15 of the second stage module. 16 is connected by passing a connection pin 35 made of a conductive material through the connection holes 27 and 17, and similarly, the second metal foil outer exposed portion 26 of the second layer module and the third layer module are exposed. The first metal foil outer exposed portion 16 is connected, and the second metal foil outer exposed portion 26 of the third layer module and the first metal foil outer exposed portion 16 of the lowermost fourth layer module are connected. I have. Further, a positive electrode pin 36 made of a conductive material is attached to the connection hole 17 of the first metal foil outer exposed portion 16 of the first layer module, and the connection of the fourth metal foil outer exposed portion 26 of the fourth layer is performed. A negative electrode pin 37 made of a conductive material is attached to the hole 27. With the above connection, the four power storage modules 1 are connected in series, the positive electrode pin 36 and the negative electrode pin 37 are used as electrode terminals of the battery pack 5, and the electric wire 38 can be pulled out and connected to another device.

Since the power storage module 1 has the irregularities formed on the exterior body 30, spaces 70 and 71 are formed between the power storage modules 1 that are adjacent in the stacking direction. That is, a space 70 having a rectangular cross section of (width of the battery element chamber 40) × (height of the embossed portion 28) is formed below the battery element chamber 40, and is formed above the heat sealing section 50 (heat sealing section 50). A space 71 having a rectangular cross section of (width of) × (height of the embossed portion 18) is formed. Since the battery element chambers 40 and the heat sealing portions 50 are alternately arranged, all the battery element chambers 40 are in contact with the spaces 70 and 71 in both the laminating direction and the direction orthogonal to the laminating direction.

  The capacity of the battery pack 5 is increased by connecting a plurality of power storage modules 1, but the amount of generated heat is large. In the battery pack 5, the heat generated by the power storage module 1 is radiated to the spaces 70 and 71, and the gas flows into the spaces 70 and 71 to promote the heat radiation and cool the battery. The spaces 70 and 71 are heat radiation spaces formed by laminating the power storage modules 1, and can exhibit heat radiation performance without using a heat radiation member such as a corrugated material, and can provide a cooling effect without increasing the size of the assembled battery. Can be obtained. Cooling using such spaces 70 and 71 is an effect peculiar to a structure in which a plurality of power storage modules 1 are stacked, and cannot be obtained by a single module.

  The cooling effect is enhanced by forcibly blowing air into the spaces 70 and 71, and further enhanced by sending cool air. However, even if the air is not forcibly blown, if a temperature difference occurs in the battery pack 5 due to heat generation, natural convection occurs, so that an appropriate cooling effect can be obtained.

  In order to form a space in the assembled battery, it is a condition that the battery element chamber is formed by the embossed portion and has a convex portion on the outer surface of the exterior body. The form of the embossed portion and the battery element chamber is not limited to the embodiment shown in FIG. 1B and the like, and if the embossed portion is formed on at least one of the first exterior material and the second exterior material, the exterior body Can be formed on the outer surface of the substrate. However, as in the above embodiment, when the height of the space required as the battery element chamber 40 is satisfied by the space generated by the formation of the first metal foil inner exposed portion 14 and the second metal foil inner exposed portion 24, The embossed portions 18 and 28 are provided on both the one exterior material 10 and the second exterior material 20, and the other embossed portion 28 is fitted into one of the embossed portions 18 so that the battery element chamber 40 can be attached to the exterior body 30 without increasing its thickness. This is an aspect in which unevenness is formed. Also, the width of the heat sealing portion 50 is naturally set to a size that can secure the tightness of the battery element chamber 40, but the size of the heat sealing portion is further increased in order to enlarge the heat radiation space. You are free to make it bigger.

  Further, the layout of the heat radiation space can be changed depending on the lamination mode of the power storage module.

  In the battery pack 6 shown in FIG. 3, the power storage modules 1 are stacked alternately at different positions, and the center of the battery element chamber 40 of one module 1 is formed by the heat sealing portion 50 of the module 1 adjacent in the stacking direction. It is arranged so as to overlap the intersection. The shift amount is １ ／ of the distance between the battery element chambers 40. By shifting the position of the power storage module 1 in this manner, the battery element chambers 40 and the spaces 70 and 71 are arranged in a staggered manner in the stacking direction. Since the positions of the connection holes 17 and 27 of the adjacent modules are shifted by shifting the power storage module 1, the widths of the first flange 15 and the second flange 25 are changed to adjust the positions of the connection holes 17 and 27. Is going. Therefore, the shape of the power storage module 1 shown in FIG. 3 is not strictly the same as that of the power storage module 1 shown in FIGS. 1A to 2B, but the same reference numerals are used to simplify the description and illustration. The assembled battery 6 is similar to the assembled battery 5 in that four power storage modules 1 are connected in series by connection pins 35, and are attached to the positive electrode pins 36 attached to the first layer module and the fourth layer module. The negative electrode pin 37 is used as an electrode terminal of the battery pack 6.

  According to the above-described stacked structure, the battery element chambers 40 are arranged in a staggered manner in the stacking direction, the distance between the battery element chambers 40 is increased, and the battery element chambers 40 are dispersed in the assembled battery 6. The temperature rise is suppressed by dispersing the battery element chamber 40 that is a heat generation source. Furthermore, since the space 70 below the battery element chamber 40 and the space 71 above the heat sealing portion 50 are combined to form a large space, the heat radiation efficiency is improved. Thus, the cooling efficiency can be improved.

Further, as another means for improving the cooling effect, there is a method of interposing a plate-type heat transfer body 75 between the power storage modules 1. In the assembled battery 7 of FIG. 4, a cooling effect is enhanced by interposing a metal plate as the heat transfer body 75 and discharging heat to the metal plate. The material of the heat transfer body 75 is preferably aluminum or copper having high thermal conductivity, and a heat absorbing gel may be added to these metal plates.
[Materials and Preparation of First and Second Exterior Materials]
The first exterior material 10 has a first heat-resistant resin layer 12 attached to one surface of a first metal foil 11 via a first adhesive layer, and a first thermoplastic resin layer attached to the other surface via a second adhesive layer. The resin layer 13 is bonded. The first metal foil inner exposed portion 14 is formed by removing the first thermoplastic resin layer 13 and the second adhesive layer, and the first metal foil outer exposed portion 16 is formed of the first thermoplastic resin layer 13 according to the surface to be formed. It is formed by removing the resin layer 13 and the second adhesive layer, or the first heat-resistant resin layer 12 and the first adhesive.

  The second exterior material 20 has a second heat-resistant resin layer 22 attached to one surface of a second metal foil 21 via a third adhesive layer, and a second thermoplastic resin layer attached to the other surface via a fourth adhesive layer. The resin layer 23 is bonded. Like the first exterior material 20, the second metal foil inner exposed portion 24 is formed by removing the second thermoplastic resin layer 23 and the fourth adhesive layer, and the second metal foil outer exposed portion 26 is formed on the surface to be formed. The second thermoplastic resin layer 23 and the fourth adhesive layer, or the second heat-resistant resin layer 22 and the third adhesive layer are removed in accordance with.

  1B omits illustration of the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer.

  A preferred material for the first metal foil 11 is a soft aluminum foil, and the thickness is preferably 7 to 150 μm. A soft aluminum foil having a thickness of 30 to 80 μm is particularly preferable in terms of moldability and cost. On the other hand, preferred materials for the second metal foil 21 are soft or hard aluminum foil, stainless steel foil, nickel foil, copper foil, and titanium foil. The preferred thickness of these foils is 7 to 150 μm, and preferably 15 to 100 μm in terms of impact resistance, bending resistance and cost.

  Further, the first metal foil 11 and the second metal foil 21 may be plated foils or clad foils. For example, as the second metal foil 21, a plated foil obtained by plating nickel on copper or a clad foil of stainless steel and nickel can be used.

Further, it is preferable that a chemical conversion film is formed on at least the surface of the first metal foil layer 11 and the second metal foil layer 21 on the side where the metal foil exposed portions 14, 16, 24, 26 exist. The chemical conversion film is a film formed by performing a chemical conversion treatment on the surface of the metal foil. By performing such a chemical conversion treatment, corrosion of the metal foil surface due to contents (electrolyte or the like) is sufficiently prevented. In addition, even in the exposed portion serving as a window for taking out electricity, discoloration or deterioration does not occur even if an electrolyte is adhered when manufacturing a module, and the influence of corrosion due to moisture in the atmosphere can be reduced. Although the chemical conversion treatment layer itself has little conductivity, the thickness of the coating film is extremely small, so that there is almost no current-carrying resistance. For example, a chemical conversion treatment is performed on the metal foil by performing the following treatment. That is, on the surface of the metal foil subjected to the degreasing treatment,
1) phosphoric acid,
Chromic acid and
An aqueous solution of a mixture containing at least one compound selected from the group consisting of a metal salt of fluoride and a nonmetal salt of fluoride; 2) phosphoric acid;
An acrylic resin, at least one resin selected from the group consisting of a chitosan derivative resin and a phenolic resin,
An aqueous solution of a mixture containing at least one compound selected from the group consisting of chromic acid and a chromium (III) salt; 3) phosphoric acid;
An acrylic resin, at least one resin selected from the group consisting of a chitosan derivative resin and a phenolic resin,
At least one compound selected from the group consisting of chromic acid and chromium (III) salts,
An aqueous solution of a mixture containing at least one compound selected from the group consisting of a metal salt of fluoride and a non-metal salt of fluoride, and applying an aqueous solution of any of the above 1) to 3) to the surface of the metal foil After working, a chemical conversion treatment is performed by drying.

The conversion coating, chromium coating weight preferably is 0.1mg ^{/ m 2} ~50mg ^/ m 2 as a (per one surface), in particular ^2mg / ^{m 2 ~20mg} / m ² preferred.

  As the heat-resistant resin constituting the first heat-resistant resin layer 12 and the second heat-resistant resin layer 22, a heat-resistant resin that does not melt at the heat sealing temperature at the time of heat-sealing the exterior material is used. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point higher than the melting point of the thermoplastic resin constituting the thermoplastic resin layers 13 and 23 by 10 ° C. or more, and a melting point higher by 20 ° C. or more than the melting point of the thermoplastic resin. It is particularly preferable to use a heat resistant resin having For example, in addition to a polyester film and a polyamide film, a stretched film such as a polyethylene naphthalate film, a polybutylene naphthalate film, and a polycarbonate film is preferable. The thickness is preferably in the range of 9 to 50 μm.

  As the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23, at least one thermoplastic resin selected from the group consisting of polyethylene, polypropylene, olefin-based copolymers, acid-modified products thereof and ionomers Is preferable, and the thickness is preferably in the range of 20 to 80 μm.

The first adhesive layer and the third adhesive layer are preferably two-component curable polyester polyurethane-based or polyether polyurethane-based adhesives, and the second adhesive layer and the fourth adhesive layer are polyolefin-based in consideration of electrolyte resistance. Are preferred. Preferred application of the respective adhesive is 1 to 5 g / ^{m 2.}

The first exterior material 10 and the second exterior material 20 may be formed by forming a metal exposed portion in a bonding step of each layer and then forming a polar material layer, or by forming a polar active material layer on a metal foil in a bonding step of each layer. Can be produced by forming Details are as follows.
(I) Manufacturing method of forming exposed metal part in bonding step For example, in a step of bonding a metal foil and a resin layer by a dry lamination method, using a gravure roll engraved on a portion where the adhesive is not to be adhered, After application, an adhesive-uncoated portion is formed, and the metal foil and the resin layer are bonded together, the resin layer on the adhesive-uncoated portion is cut off to expose the metal foil. Since the first exterior material 10 used in the power storage module 1 of the above embodiment has the metal foil exposed portions 14 and 16 on the surface on the thermoplastic resin layer 13 side, the first metal foil 11 And the first thermoplastic resin layer 13 are bonded, and after bonding, the metal foil exposed portions 14 and 16 are formed.

  On the other hand, the first metal foil 11 and the first heat resistant resin layer 12 are bonded by a well-known bonding method because there is no exposed metal portion on the surface on the heat resistant resin layer 12 side. The order in which the first heat-resistant resin layer 12 and the first thermoplastic resin layer 13 are bonded does not matter, and either one may be bonded first.

  The periphery of the first metal foil inner exposed portion 14 formed by the above process is masked with an easily peelable adhesive tape or the like, and the composition for the binder layer 64 and the composition for the positive electrode active material layer 61 are sequentially applied and dried. . After the positive electrode active material layer 61 is completed by drying, the masking is removed.

  In the same manner, the second exterior material 20 is bonded to the second metal foil 21, the second heat-resistant resin layer 22, and the second thermoplastic resin layer 23, the second metal foil inner exposed portion 24, and the second metal foil. The formation of the exposed portion 26 inside the foil and the lamination of the binder layer 65 and the negative electrode active material layer 63 are performed.

In the case where the metal foil outside exposed portion is formed on the first heat-resistant resin layer 12 and / or the second heat-resistant resin layer 22 side surface of the first exterior material 10 and / or the second exterior material 20, After bonding the first metal foil 11 and the first heat resistant resin layer 12 and the second metal foil 21 and the second heat resistant resin layer 22 by a technique, the resin layer is removed.
(II) Method of Laminating Each Layer After Coating of Polar Active Material Layer A composition for the binder layer 64 and a composition for the positive electrode active material layer 61 are applied to a portion of the first metal foil 11 to be the first metal foil inside exposed portion 14. The binder layer 64 and the positive electrode active material layer 61 are laminated by sequentially applying and drying. Next, the surface of the positive electrode active material layer 61 is masked with an easily peelable adhesive tape or the like, and the first metal foil 11 and the first thermoplastic resin layer 13 are bonded to each other using a first adhesive. The first heat-resistant resin layer 12 is bonded to the opposite surface of the first metal foil 11 using a second adhesive. Then, the first thermoplastic resin layer 13 on the positive electrode active material layer 61 is cut off. Since the easily peelable adhesive tape and the first thermoplastic resin layer 13 are strongly bonded with the second adhesive, the easily peelable adhesive tape is removed together with the first thermoplastic resin layer 13, and the positive electrode active material layer 61 is removed. Exposed. The positive electrode active material layer 61 is laminated on the first metal foil inner exposed portion 14.

  Since the positive electrode active material layer 61 is not laminated on the first metal foil outer exposed portion 16, a required portion of the first metal foil 11 is masked with an easily peelable adhesive tape, and the first thermoplastic resin layer 13 is attached. It can be formed by removing the easily peelable adhesive tape together with the first thermoplastic resin layer 13. Alternatively, the first metal foil outer exposed portion 16 can also be formed by the method of forming the uncoated portion of the adhesive (I) and bonding the first metal foil 11 and the thermoplastic resin layer 13 together.

  On the other hand, since there is no metal exposed portion on the surface on the first heat resistant resin layer 12 side, the first metal foil 11 and the first heat resistant resin layer 12 are bonded by a known bonding method. The order in which the first heat-resistant resin layer 12 and the first thermoplastic resin layer 13 are bonded does not matter, and either one may be bonded first.

  The same procedure is applied to the second exterior material 20 to coat the binder layer 65 and the negative electrode active material layer 63, and to bond the second metal foil 21, the second heat-resistant resin layer 22, and the second thermoplastic resin layer 23. Then, the second thermoplastic resin layer 23 and the easily peelable pressure-sensitive adhesive tape are removed to expose the negative electrode active material layer 63, thereby forming the second metal foil outer exposed portion 26.

  After the lamination of each layer and the formation of the pole active material layer by any of the methods (I) and (II), an embossed portion is formed by press molding.

  For example, the embossed portion 18 of the first exterior material 10 illustrated in FIG. 1A and the like is pressed by a molding die including a male mold in which the positive electrode active material layer 61 is in contact with the top surface, a female mold in which the male mold is inserted, and a holding mold. It is formed by molding. Since the embossed portion 28 of the second exterior material 20 projects in the opposite direction to the embossed portion 28, press molding is performed such that the male top surface is in contact with the opposite surface of the negative electrode active material layer 63. At this time, it is preferable to press the second thermoplastic resin layer 23 with the same material as the separator 62 so as to prevent the negative electrode active material layer 63 from peeling off and to adjust the size when fitting.

  The first exterior material 10 and the second exterior material 20 having the embossed portions are trimmed to required dimensions, and connection holes 17 and 27 are formed in the first metal foil outer exposed portion 16 and the second metal foil outer exposed portion 26. I do. In addition, if the first exterior material 10 is cut in such a manner that two sides without the first flange slightly protrude from the second exterior material 20 and the protruding portion is bent after heat sealing, the first metal on the cut end face can be obtained. Contact between the foil 11 and the second metal foil 21 can be prevented. The dimensions of the first exterior material 10 and the second exterior material 10 may be reversed, and the second exterior material 20 may be bent.

The present invention does not limit the manufacturing method of the first exterior material and the second exterior material to the above-described method, and does not exclude an exterior material produced by another method. In the power storage module of the present invention, since the pole active material layer is laminated on the metal foil constituting the exterior material and has an embossed portion, according to the above method, the pole active material layer is provided and the embossed portion is formed. The obtained first and second exterior materials can be efficiently produced.
[Structure and material of battery element]
The core cell 60 as a battery element includes a positive electrode active material layer 61 laminated on the first metal foil inner exposed portion 14, a separator 62, a negative electrode active material layer 63 laminated on the second metal foil inner exposed portion 24, and the accompanying Layer. The binder layers 64 and 65 are not indispensable layers, but are preferably layers interposed between the metal foil and the pole active material layer in order to enhance the adhesion between them. The preferred composition and thickness of each layer of the core cell 60 and the electrolyte enclosed with the core cell 60 are as follows. In addition, the composition described below is an example, and the present invention is not limited to these.

  The positive electrode active material layer 61 is made of, for example, a binder such as PVDF (polyvinylidene fluoride), SBR (styrene butadiene rubber), CMC (sodium carboxymethylcellulose), PAN (polyacrylonitrile), a linear polysaccharide, or the like. It is formed of a mixed composition to which a salt (for example, lithium cobaltate, lithium nickelate, lithium iron phosphate, lithium manganate, or the like) is added. It is preferable that the thickness of the positive electrode active material layer 61 is set to 2 μm to 300 μm. The positive electrode active material layer 61 may further contain a conductive auxiliary such as carbon black or CNT (carbon nanotube).

  The negative electrode active material layer 63 includes, for example, a binder such as PVDF, SBR, CMC, PAN, or linear polysaccharide, and an additive (eg, graphite, lithium titanate, Si-based alloy, tin-based alloy, etc.) added thereto. It is formed of a mixed composition or the like. The thickness of the negative electrode active material layer 63 is preferably set to 1 μm to 300 μm. The negative electrode active material layer 63 may further contain a conductive auxiliary such as carbon black or CNT (carbon nanotube).

  The separator 62 is, for example, a polyethylene separator, a polypropylene separator, a separator formed of a multilayer film composed of a polyethylene film and a polypropylene film, or a wet or dry type in which a heat-resistant inorganic material such as ceramic is applied to a resin separator thereof. And the like. It is preferable that the thickness of the separator 62 is set to 5 μm to 100 μm.

  Preferably, the separator 62 has a size 2 to 5 mm larger than each side of the opening of the embossed portion (battery element chamber) in order to ensure insulation. In addition, if the separator is not coated with a heat-resistant inorganic substance, it fuses with the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 during heat sealing, so that a large number of battery element chambers and the heat sealing portion are covered. Size separators can also be used. 1B, all the battery element chambers 60 are covered by one separator 62.

  Examples of the binder layer 64 include a layer formed of PVDF, SBR, CMC, PAN, linear polysaccharide, or the like. Further, in order to improve the conductivity between the first metal foil 11 and the positive electrode active material layer 61, a conductive auxiliary such as carbon black or CNT (carbon nanotube) is further added to the binder layer 64. Is also good. The thickness of the binder layer 64 is preferably set to 0.2 μm to 10 μm. By setting the binder layer 64 to 10 μm or less, an increase in the internal resistance of the core cell 60 due to the binder having no conductivity can be suppressed as much as possible.

  Examples of the binder layer 65 include a layer formed of PVDF, SBR, CMC, and PAN. In order to improve the conductivity between the second metal foil 21 and the negative electrode active material layer 63, a conductive auxiliary such as carbon black and CNT may be further added to the binder layer 65. It is preferable that the thickness of the binder layer is set to 0.2 μm to 10 μm. By setting the binder layer to 10 μm or less, an increase in the internal resistance of the core cell 60 due to the binder having no conductivity can be suppressed as much as possible.

  When laminating the binder layer 64 and the positive electrode active material layer 61 on the first metal foil inner exposed portion 14 of the first exterior material 10, the composition of each layer is sequentially applied to the first metal foil 11 and dried. When the binder layer 65 and the negative electrode active material layer 63 are laminated on the second metal foil inner exposed portion 24 of the second exterior material 20, the same procedure is performed.

  Examples of the electrolyte include an electrolyte containing at least one solvent selected from the group consisting of water, ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and dimethoxyethane, and a lithium salt. Examples of the lithium salt include, but are not particularly limited to, lithium hexafluorophosphate, lithium tetrafluoroborate, and quaternary ammonium tetrafluoroborate. Examples of the quaternary ammonium salt include a tetramethylammonium salt. The above-mentioned electrolyte may be gelled with PVDF, PEO (polyethylene oxide) or the like.

  Further, when the power storage module of the present invention is an electric double layer capacitor, preferred materials are as follows.

Both the first metal foil 11 and the second metal foil 21 are preferably formed of a hard aluminum foil having a thickness of 7 μm to 50 μm. Further, it is preferable that the positive electrode active material layer and the negative electrode active material layer are formed of a composition containing a conductive material such as carbon black or CNT (carbon nanotube). The separator is preferably a porous polycellulose membrane having a thickness of 5 μm to 100 μm or a nonwoven fabric having a thickness of 5 μm to 100 μm.
[Method of manufacturing power storage module]
The power storage module 1 sandwiches the separator 62 in the step of assembling the exterior body 30 with the first exterior material 10 and the second exterior material 20, injects an electrolyte, and heat seals. The first packaging material 10 and the second packaging material 20 described here have a positive electrode active material layer 61 and a negative electrode active material layer 63 laminated thereon and have embossed portions 18 and 28 formed thereon.
(1) The first exterior material 10 is placed so that the first thermoplastic resin layer 13 faces upward, and an electrolyte is injected into a depression formed by each first embossed portion 18.
(2) The separator 62 is placed on the first exterior material 10, and the second exterior material 20 is further stacked thereon, and the second embossed portion of the second exterior material 28 is placed on the first embossed portion 18 of the first exterior material 10. 28 is fitted to assemble the exterior body 30. The battery element chamber 40 is formed by this assembly. In this assembled state, the first flange 15 extends from the end of the second exterior material 20 and the second flange 25 extends from the end of the first exterior material 10, and the first metal foil outer exposed 16 And the second metal foil outer exposed portion 26 is exposed on the outer surface of the exterior body 30.
(3) Temporarily press the outer peripheral portions of the nine battery element chambers 40, that is, the four outer peripheral portions of the first exterior material 10 and the second exterior material 20 with a clip or the like, and outside the first metal foil of the first flange 15 Pre-charging is performed by connecting a clip to the exposed portion 16 and the exposed portion 26 of the second metal foil outside of the second flange 25, and the battery is put in a constant temperature bath at 100 ° C. for 8 hours to degas the battery element chamber 40.
(6) Under reduced pressure, the upper and lower sides of four surrounding sides of each battery element chamber 40 are sandwiched between hot plates and heat sealed to form heat sealed portions 50. By this heat sealing, the core cell 60 and the electrolyte are sealed in the battery element chamber 40.

  The above manufacturing method is merely an example, and is not particularly limited to such a manufacturing method.

  The assembled battery is formed by laminating a required number of power storage modules or laminating with a heat transfer body 75 interposed therebetween, and connecting adjacent modules in the laminating direction by the above-described method. The number of layers in the battery pack of the present invention is arbitrary.

  Although the use of the assembled battery according to the present invention is not limited, power sources for automobiles, bicycles, two-wheeled vehicles, trains, airplanes, ships, and the like that require electricity, specifically, hybrid vehicles and electric vehicles, industrial and household storage batteries, and the like. Large lithium secondary battery (lithium ion battery, lithium polymer battery, etc.) module, solid state battery module, lithium ion capacitor module for the same application, and electric double layer capacitor module for the same application.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.
<Example 1>
The power storage module 1 having the structure shown in FIGS. 1A and 1B was manufactured.

The first exterior material 10 and the second exterior material 20 that constitute the exterior body 30 of the power storage module 1 are “(II) bonding each layer after coating the pole active material layer” of the above two methods. It was produced based on.
(Preparation of the first exterior material)
The first metal foil 11 is a soft aluminum foil of A8079 classified by JIS H4160 and having a thickness of 40 μm, and a chemical conversion treatment is applied to both surfaces. The first heat-resistant resin layer 12 is a biaxially stretched polyamide film having a thickness of 25 μm, and the first adhesive is a two-component curable polyester polyurethane adhesive. The first thermoplastic resin layer 13 is an unstretched polypropylene film having a thickness of 40 μm, and the second adhesive is a two-component curable olefin-based adhesive. As a paste for the positive electrode active material layer 61, 100 parts by weight of a positive electrode active material containing lithium cobalt oxide as a main component, 5 parts by weight of acetylene black as a conductive material, and 10 parts by weight of vinylidene fluoride as a binder and an electrolyte retainer Used was a paste kneaded and dispersed in an organic solvent. PVDF dissolved in dimethylformamide was used as an adhesive for the binder layer 64.

  The size of the first metal foil inner exposed portion 14 was 30 mm × 30 mm, and nine pieces were formed in 3 rows × 3 rows. The dimension of the first metal foil outer exposed portion 16 is 20 mm × 140 mm.

  On one surface of the first metal foil 11, an adhesive for the binder layer 64 was applied at nine intervals to become nine first metal foil inner exposed portions 14 at intervals of 20 mm. One application part of the binder layer 64 is 30 mm × 30 mm, and the application thickness is 0.5 μm. The paste for the positive electrode active material layer 61 was applied on the binder layer 64 and dried to form the positive electrode active material layer 61 having a thickness of 30 μm. A polyester adhesive tape for masking is stuck on the positive electrode active material layer 61, and a second adhesive is applied by a dry lamination method so that a portion corresponding to the first metal foil outer exposed portion 16 becomes an adhesive uncoated portion. The first thermoplastic resin layer 13 was adhered by coating so as to have a thickness of 3 μm, and cured in an aging furnace at 50 ° C. for 3 days. Next, the first thermoplastic resin layer 13 at the portion where the polyester adhesive tape was applied and the portion where the adhesive was not applied were cut off with a laser knife. Thereby, the positive electrode active material layer 61 laminated on the first metal foil inner exposed portion 14 was exposed, and the first metal foil outer exposed portion 16 was formed.

  A first adhesive is applied to the other surface of the first metal foil 11 by a dry laminating method so as to have a thickness of 3 μm, and the first heat-resistant resin layer 12 is bonded thereto. Cured for days.

  Nine positive electrode active material layers 61 were formed at the nine locations of the first exterior material 10 by press molding to form embossed portions 18 protruding from the surface on the first heat resistant resin layer 12 side. The embossed portion 18 has a size of 40 mm × 40 mm × 4 mm in depth, and the positive electrode active material layer 61 is exposed at the center inside the top surface.

The first exterior member 10 was trimmed to have a shape having a plane size of 180 mm × 150 mm, and a connection hole 17 was formed in the first metal foil outer exposed portion 16.
(Second exterior material)
The second metal foil 21 is a hard copper foil of 15 μm in thickness of C1100R classified according to JIS H3100, and a chemical conversion treatment is applied to both surfaces. The second heat-resistant resin layer 22 is a biaxially stretched polyester film having a thickness of 12 μm, and the third adhesive is a two-component curable polyester polyurethane adhesive. The second thermoplastic resin layer 23 is an unstretched polypropylene film having a thickness of 40 μm, and the fourth adhesive is a two-component curable olefin-based adhesive. As a paste for the negative electrode active material layer 63, 57 parts by mass of a negative electrode active material mainly composed of carbon powder, 5 parts by mass of PVDF as a binder and an electrolyte retainer, and 10 parts by mass of a copolymer of hexafluoropropylene and maleic anhydride Of acetylene black (conductive material) and 25 parts by mass of N-methyl-2-pyrrolidone (organic solvent). PVDF dissolved in dimethylformamide was used as an adhesive for the binder layer 65.

  On one surface of the second metal foil 21, an adhesive for the binder layer 65 was applied at intervals of 50 mm to nine locations serving as the second metal foil inner exposed portions 24, and dried at 100 ° C. for 30 minutes. One applied portion of the binder layer 65 is 30 mm × 30 mm, and the applied thickness after drying is 0.5 μm. The paste for the negative electrode active material layer 63 was applied on the binder layer 65, dried at 100 ° C. for 30 minutes, and further subjected to hot pressing to obtain a negative electrode active material having a density of 1.5 g / cm and a thickness of 20.1 μm. A material layer 63 was formed. A polyester adhesive tape for masking is attached on the negative electrode active material layer 63, and a fourth adhesive is applied by a dry lamination method so that a portion corresponding to the second metal foil outer exposed portion 26 is an adhesive uncoated portion. It was applied so as to have a thickness of 3 μm, and the second thermoplastic resin layer 23 was adhered thereto, and cured in an aging furnace at 50 ° C. for 3 days. Next, the second thermoplastic resin layer 23 in the portion where the polyester adhesive tape was applied and the portion where the adhesive was not applied were cut off with a laser knife. Thereby, the negative electrode active material layer 63 laminated on the second metal foil inner exposed portion 14 was exposed, and the second metal foil outer exposed portion 26 was formed.

  A third adhesive is applied to the other surface of the second metal foil 21 by a dry laminating method so as to have a thickness of 2 μm, and the second heat-resistant resin layer 22 is bonded thereto. Cured for days.

  The nine negative electrode active material layers 63 of the second exterior material 20 were press-formed from opposite sides to form embossed portions 28 protruding from the second thermoplastic resin layer 23 side. The embossed portion 28 is 40 mm × 40 mm × 4 mm in depth, and the negative electrode active material layer 63 is exposed at the center outside the top surface.

The second exterior member 20 was trimmed to have a planar dimension of 180 mm × 150 mm, and a connection hole 27 was formed in the second metal foil outer exposed portion 26.
(Production of power storage module)
As the separator 62, a porous wet-type separator made of polypropylene and having a thickness of 140 μm and a thickness of 8 μm was used. The size of the separator 62 is set so that the positive electrode active material layer 61 and the negative electrode active material layer 63 of the nine battery element chambers 40 can be insulated by one separator 62. Lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1 mol / L in a mixed solvent in which ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) were blended in an equal volume ratio as an electrolyte. The dissolved electrolyte was used.

The first exterior material 10 was placed such that the first thermoplastic resin layer 13 was facing upward, and 5 mL of the electrolyte was injected into the depression formed by each first embossed portion 18. The separator 62 is placed on the first exterior material 10, and the second exterior material 20 is further stacked thereon, and the second embossed portion 28 of the second exterior material 28 is placed on the first embossed portion 18 of the first exterior material 10. The battery case 40 was formed by assembling and mounting the exterior body 30. In this assembled state, the first flange 15 extends from the end of the second exterior material 20 and the second flange 25 extends from the end of the first exterior material 10, and the first metal foil outer exposed 16 And the second metal foil outer exposed portion 26 is exposed on the outer surface of the exterior body 30. The outer peripheral portions of the nine battery element chambers 40, that is, the four sides of the outer peripheral portions of the first exterior material 10 and the second exterior material 20 are temporarily held down by clips, and the first metal foil outer exposed portion 16 of the first flange 15 and A clip is connected to the second metal foil outer exposed portion 26 of the second flange 25 to perform pre-charging until a battery voltage of 4.2 V is generated. Drilling was performed. After degassing, in a discharge state of 3.0 V and under a reduced pressure of 0.086 MPa, each of the battery element chambers 40 is sandwiched by a hot plate of 200 ° C. at a pressure of 0.3 MPa between the upper and lower sides of four surrounding sides. Heat sealing was performed for 3 seconds. By this heat sealing, the core cell 60 and the electrolyte were sealed in the battery element chamber 40.
<Comparative Example 1>
A flat power storage module was manufactured using the first exterior material and the second exterior material having no embossed portion. The first exterior material and the second exterior material are common to the first exterior material 10 and the second exterior material 20 of the first embodiment except that they have no embossed portion.

First, the first exterior body and the second exterior body were opposed to each other. At this time, an outer package was assembled by sandwiching a separator between the two and sandwiching the injection needle so as to reach the positions of the respective positive electrode active material layers and the negative electrode active material layers. The end of the injection needle is drawn out of the exterior body. The periphery of each of the positive electrode active material layer and the negative electrode active material layer was heat-sealed to form a heat-sealed portion, an electrolyte was injected through an injection needle, and the injection needle was sealed. Preliminary charging was performed under the same conditions as in Example 1, and the sample was put in a thermostat at 100 ° C. for 8 hours to release gas. After degassing, the injection needle was withdrawn, and the hole of the trace was pinched with a hot plate at 200 ° C. at a pressure of 0.3 MPa under a discharge state of 3.0 V and a reduced pressure of 0.086 MPa, and heat sealed for 3 seconds. went. By this heat sealing, the core cell and the electrolyte were sealed in the battery element chamber.
<Evaluation>
The power storage modules of Example 1 and Comparative Example 1 obtained as described above were evaluated based on the following evaluation method. Table 1 shows the evaluation results.

  After the power storage module was fully charged to 4.2 V, 1C charge / discharge (charge in 1 hour, discharge in 1 hour) was repeated 100 times at room temperature of 18 ° C., and the voltage and capacity at the time of full charge again were measured. Further, when the fully charged battery was discharged at 1 C, the temperature at the time of discharging at 0.2 C was measured by a temperature sensor, and an average value was obtained. The temperature measurement position is the central part of the outer surface of the battery cell chamber at the center of 3 rows × 3 rows in both Example 1 and Comparative Example 1.

  As shown in Table 1, there was no difference in the battery capacity between Example 1 and Comparative Example 1, and the same result was obtained even after 100 cycles of charging and discharging. Regarding the calorific value at the time of discharging, it was confirmed that the assembled battery of Example 1 suppressed heat generation and had a high heat radiation effect as compared with Comparative Example 1 at both 1C discharging and 0.2 discharging.

  Also, from the above evaluation results, it is clear that a difference in the heat radiation effect occurs even in an assembled battery in which a plurality of power storage modules are stacked.

  The power storage module of the present invention can be suitably used as various power supplies.

DESCRIPTION OF SYMBOLS 1 ... Electric storage module 5, 6, 7 ... Battery 10 ... First exterior material 11 ... First metal foil 12 ... First heat resistant resin layer 13 ... First thermoplastic resin layer 14 ... First metal foil inner exposed part 15 ... first flange 16 ... first metal foil outer exposed part 18 ... first embossed part 20 ... second exterior material 21 ... second metal foil 22 ... second heat resistant resin layer 23 ... second thermoplastic resin layer 24 ... Bimetallic foil inner exposed portion 25 second flange 26 second metal foil outer exposed portion 28 second embossed portion 30 exterior body 40 battery element chamber 50 heat sealing portion 60 core cell (battery element)
61 ... Positive electrode active material layer 62 ... Separator 63 ... Negative electrode active material layer 70, 71 Space 75 ... Heat transfer material

Claims (4)

The first heat-resistant resin layer is laminated on one surface of the first metal foil, the first thermoplastic resin layer is laminated on the other surface, and the first metal foil is exposed on the surface on the first thermoplastic resin layer side. A first exterior material having a first metal foil inner exposed portion,
A second heat-resistant resin layer is laminated on one surface of the second metal foil and a second thermoplastic resin layer is laminated on the other surface, and the second metal foil is exposed on the surface on the second thermoplastic resin layer side. A second exterior material having a second metal foil inner exposed portion,
A positive electrode active material layer stacked on the first metal foil inner exposed portion, a negative electrode active material layer stacked on the second metal foil inner exposed portion, and a battery element having a separator disposed therebetween. ,
The first exterior material and the second exterior material have an embossed portion in a region including the first metal foil inside exposed portion and the second metal foil inside exposed portion, and the first thermoplastic resin layer of the first exterior material. By facing the second thermoplastic resin layer of the second exterior material and being surrounded by the heat-sealed portion where the first thermoplastic resin layer and the second thermoplastic resin layer are fused, the inside of the first metal foil inside the room It has an exposed portion and a second metal foil inner exposed portion 1 or more rooms of the battery element chamber facing, and made an outer surface having an uneven by embossing unit comprising a rising wall of the heat sealing unit, the battery element chamber and the heat An exterior body in which a space is formed by the rising wall of the sealing portion is formed,
In the battery element sealed together with the electrolyte in the battery element chamber, the positive electrode active material layer is electrically connected to the first metal foil inside exposed portion, and the negative electrode active material layer is electrically connected to the second metal foil inside exposed portion. Power storage module.   The outer surface of the exterior body, wherein at least one of a first metal foil outer exposed portion where the first metal foil is exposed and a second metal foil outer exposed portion where the second metal foil is exposed are formed. Power storage module. A power storage module comprising two or more power storage modules according to claim 1 or 2, wherein the power storage modules are stacked in such a manner that a space is formed between adjacent power storage modules by the uneven surface of the exterior body . In the stacking direction, a plurality of power storage modules are stacked such that the battery element chamber and the heat sealing portion overlap, and a space formed by the rising wall of the battery element chamber and the heat sealing portion; An assembled battery, wherein a space formed by a sealing portion is adjacent to the power storage module, and the power storage modules are connected in series. The battery pack according to claim 3 , wherein a heat transfer body is disposed between the power storage modules adjacent in the stacking direction.

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