CN106058363B

CN106058363B - Battery pack

Info

Publication number: CN106058363B
Application number: CN201610232746.4A
Authority: CN
Inventors: 南谷广治; 长冈孝司; 池田贤史
Original assignee: Showa Denko Packaging Co Ltd
Current assignee: Lishennoco Packaging Co ltd
Priority date: 2015-04-15
Filing date: 2016-04-14
Publication date: 2020-04-17
Anticipated expiration: 2036-04-14
Also published as: JP6611455B2; JP2016207267A; TWI699925B; KR20160123246A; TW201637264A; CN106058363A; KR102488346B1; CN205723858U

Abstract

The invention provides a battery pack. An outer package (32) of a laminated electricity storage module (2) has an embossed section (45) on at least one of a first outer package (10) and a second outer package (20) that face each other, and has a plurality of electrode element chambers (42) that are formed by heat-sealing the periphery of the embossed section (45) to form projections. The battery pack (5) is formed by stacking and connecting a plurality of the modules (2) and forms a space (70) for heat dissipation by the difference in thickness between the electrode element chamber (42) and the heat-sealed portions (52a, 52 b). In the cell chamber (42), the cell (60) is connected to the metal foil inner exposed portions (14, 24), and the module (2) is connected to the metal foil outer exposed portions (16, 26).

Description

Battery pack

Technical Field

The present invention relates to a battery pack that is light in weight, high in heat dissipation, and space-saving.

In addition, in the present specification, the word "aluminum" is used in a meaning including Al and Al alloys, the word "copper" is used in a meaning including Cu and Cu alloys, the word "nickel" is used in a meaning including Ni and Ni alloys, and the word "titanium" is used in a meaning including Ti and Ti alloys. In addition, in the present specification, the word "metal" is used in a meaning including simple metals and alloys.

Background

With the miniaturization and weight reduction of lithium ion secondary batteries and lithium polymer secondary batteries used for batteries of hybrid cars and electric cars, stationary storage batteries for household and industrial use, Laminate (Laminate) exterior parts in which resin films are bonded to both surfaces of a metal foil have been used in many cases instead of metal exterior parts used in the past. In addition, it is considered to mount an electric double layer capacitor, a lithium ion capacitor, and the like using a laminated exterior part on an automobile or a bus.

In devices requiring high energy, such as electric vehicles, in order to obtain large electric energy with a small capacity, the electric storage modules are stacked and connected in series, but during charging and discharging, heat generated by internal resistance of the modules is easily accumulated, and high temperature is generated in the modules, which not only accelerates deterioration of the battery and degrades the performance of the battery, but also affects the safety of the battery. In view of this, in a battery pack in which a plurality of power storage modules are stacked, a heat dissipation member is provided between the power storage modules to cool the modules (see patent documents 1 and 2).

In the battery pack described in patent document 1, a wave-shaped member is provided as a heat radiating member between the power storage modules, and a space for flowing cold air is formed to obtain a heat radiating effect. In the battery pack described in patent document 2, a pipe member through which a cooling liquid flows is disposed between the power storage modules, and a plate spring is provided between the pipe member and the power storage modules to form a space for air cooling, thereby obtaining a high cooling effect by both liquid cooling and air cooling.

Patent document

Patent document 1: japanese patent laid-open No. 2012 and 84551

Patent document 2: japanese patent laid-open No. 2014-170697

Disclosure of Invention

However, the cooling methods described in patent documents 1 and 2 require a large heat radiating member such as a wave-shaped member, a pipe member, or a plate spring, and a device for supplying cold air or a cooling liquid, and these cooling devices occupy a large space in the battery pack. Therefore, even if the electric storage module is downsized, it is difficult to downsize the battery pack. Further, in the electricity storage module using the tab connection electrode, heat generation from the connection position of the tab, deterioration in sealing performance of the sealing portion, and the like may occur.

The present invention has been made in view of the above-described technical background, and an object thereof is to provide an assembled battery that is improved in heat dissipation performance without increasing the size thereof, and that greatly reduces the risk of liquid leakage.

In order to achieve the above object, the present invention has the following configurations.

(1) A battery pack characterized in that a battery pack is provided,

a laminated power storage module is provided with:

a first exterior member in which a first heat-resistant resin layer is laminated on one surface of a first metal foil and a first thermoplastic resin layer is laminated on the other surface, and which has a first metal foil inner side exposed portion on which the first metal foil is exposed on the first thermoplastic resin layer side surface; a second exterior member in which a second heat-resistant resin layer is laminated on one surface of a second metal foil, a second thermoplastic resin layer is laminated on the other surface, and a second metal foil inner side exposed portion to which the second metal foil is exposed is provided on the surface on the second thermoplastic resin layer side; a battery element having a positive electrode, a negative electrode, and a separator disposed therebetween,

at least one of the first exterior member and the second exterior member has an embossed portion in a region including a first metal foil inner side exposed portion and a second metal foil inner side exposed portion, and the first thermoplastic resin layer of the first exterior member and the second thermoplastic resin layer of the second exterior member are opposed to each other and surrounded by a heat-sealed portion formed by welding the first thermoplastic resin layer and the second thermoplastic resin layer, thereby forming an exterior body having a plurality of battery element cells, the battery element cells being formed into convex portions by the embossed portions, the first metal foil inner side exposed portion and the second metal foil inner side exposed portion facing each other in a cell, and a first metal foil outer side exposed portion where the first metal foil is exposed and a second metal foil outer side exposed portion where the second metal foil is exposed being formed on an outer surface of the exterior body,

a battery element sealed in the battery element chamber together with an electrolyte, wherein a positive electrode is electrically connected to the first metal foil inner exposed portion, a negative electrode is electrically connected to the second metal foil inner exposed portion,

the plurality of laminated power storage modules are laminated so as to form a space above the heat-sealed portion, and the laminated power storage modules adjacent to each other in the laminating direction are connected by the first metal foil outer exposed portion and the second metal foil outer exposed portion.

(2) In the battery pack of the preceding item (1), a plurality of laminated power storage modules are laminated such that the cell compartments and the heat-sealed portions overlap each other in the lamination direction of the laminated power storage modules.

(3) In the battery pack according to the aforementioned item (1) or (2), a heat conductor is disposed between the laminated power storage modules adjacent in the stacking direction.

(4) In the battery pack according to the aforementioned item (1) or (2), the space is a cooling gas flow passage.

(5) In the battery pack of the preceding item (1), the space and the cell compartment are adjacent only in a direction orthogonal to the lamination direction of the laminated type electric storage module.

(6) In the battery pack according to the aforementioned item (2), the space and the cell compartment are adjacent to each other in both the stacking direction and the direction orthogonal to the stacking direction of the laminated electric storage module.

ADVANTAGEOUS EFFECTS OF INVENTION

In the assembled battery described in the above (1), since the battery element chamber of the laminated power storage module is formed as a convex portion protruding outward of the outer package, a space is formed above the heat-sealed portion by stacking a plurality of modules. The heat generated by the battery element is radiated to the space, and the heat radiation is promoted by the gas flowing in the space, cooling the battery pack. The space is formed without using a heat radiating member, and thus, a cooling effect is obtained without enlarging the battery pack. Further, by providing a plurality of battery element chambers, the surface area of the exterior body is increased, and therefore the heat dissipation efficiency of each module is improved.

In the laminated type power storage module, the plurality of battery elements are electrically connected to each other through the first metal foil and the second metal foil via the first metal foil and the second metal foil inside exposed portions and the first metal foil outside exposed portions and the second metal foil outside exposed portions in the battery element chamber. Further, the connection between the battery pack and the external device is also performed through the first metal foil outer exposed portion and the second metal foil outer exposed portion. That is, the laminated type power storage module and the battery pack do not have tabs. Therefore, the first thermoplastic resin layer and the second thermoplastic resin layer are welded to each other at the portion of the heat-sealed portion connected to the battery element chamber, so that the adhesion is improved and the risk of liquid leakage is greatly reduced. Further, since no tab is used, the heat-sealing operation is simple, and the weight and space of the battery pack can be reduced.

In the battery pack according to the above (2), the electrode element chamber is adjacent to the space in both the stacking direction of the module and the direction orthogonal to the stacking direction, and the battery element chamber can be in contact with the space over a larger area, and a high cooling effect can be obtained.

In the battery pack according to the above (3), the heat conductor discharges heat, and thus a high cooling effect can be obtained.

In the battery pack according to the above (4), since the gas flows in the space, the heat dissipation can be promoted.

In the battery pack according to the above (5), heat generated in the cell chamber is radiated to a space adjacent to the stacked electric storage module in a direction orthogonal to the stacking direction of the stacked electric storage module.

In the battery pack according to item (6), the space is adjacent to the cell element chamber in both the stacking direction and the direction orthogonal to the stacking direction of the laminated power storage module, and thus heat dissipation can be promoted.

Drawings

Fig. 1A is a perspective view of an embodiment of a laminated power storage module constituting the battery pack of the present invention.

FIG. 1B is a cross-sectional view taken along line 1B-1B of FIG. 1A.

Fig. 2A is a perspective view of an embodiment of the battery pack of the present invention.

Fig. 2B is a cross-sectional view taken along line 2B-2B of fig. 2A.

Fig. 3 is a sectional view of a battery cell (bare cell).

FIG. 4 is a cross-sectional view showing another example of the shape of an electrode element chamber in a laminated electricity storage module.

FIG. 5 is a cross-sectional view showing another example of the shape of an electrode element chamber in a laminated electric storage module.

Fig. 6 is a sectional view of other embodiments of the battery pack of the present invention.

Fig. 7A is a sectional view of another other embodiment of the battery pack of the present invention.

Fig. 7B is a partially enlarged view of fig. 7A.

Fig. 7C is a partially enlarged view of fig. 7A.

Description of reference numerals

2, 2a, 2b, 2c, 2d … laminate type electricity storage module

5, 6, 7 … battery pack

10 … first external member

11 … first metal foil

12 … first Heat-resistant resin layer

13 … first thermoplastic resin layer

14 … first metal foil inner side exposed part

15 … first flange

16, 18 … first metal foil outer exposure

20 … second outer part

21 … second metal foil

22 … second Heat resistant resin layer

23 … second thermoplastic resin layer

24 … second metal foil inner side exposed part

25 … second flange

26, 28 … second metal foil outer exposure

32, 33, 80, 82 … outer package

42, 82, 83a, 83b cell compartment

45, 46 … embossing part

52a, 52b … Heat seal

60 … single battery (Battery component)

61 … positive pole

62 … separating sheet

63 … negative electrode

70, 71 … space

75 … thermal conductor.

Detailed Description

Fig. 1A and 1B show an embodiment of a laminated power storage module constituting the battery pack of the present invention, and fig. 2A and 2B show an embodiment of a battery pack using the laminated power storage module.

In the following description, the same reference numerals denote the same elements, and redundant description is omitted. In the first package and the second package constituting the package, regardless of the package and the formation position, when the portions where the metal foil is exposed are referred to, the portions exposed to the inside of the electrode element chamber are referred to as "metal foil exposed portions", the portions exposed to the outside surface of the package are referred to as "metal foil inside exposed portions", and the portions exposed to the outside surface of the package are referred to as "metal foil outside exposed portions".

Laminated electricity storage module

The package 32 of the laminated power storage module 2 shown in fig. 1A and 1B is composed of the first package 10 and the second package 20, and has 9 battery element chambers 42 arranged in 3 rows × 3 columns. The cell element 60 and the electrolyte are enclosed in each cell element chamber 42.

The first package 10 is a laminate 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, and 9 square embossed portions 45 in a plan view constituting a battery element chamber 42 are formed by press forming (press forming) a flat sheet. On the other hand, the second outer package 20 is a laminate in which the second heat-resistant resin layer 22 is laminated on one surface of the second metal foil 21 and the second thermoplastic resin layer 23 is laminated on the other surface, and is a flat sheet having no embossed portion. The exterior body 32 is formed with the cell element chamber 42 for enclosing the cell element 60 and the electrolyte therein by bringing the first thermoplastic resin layer 13 of the first exterior member 10 and the second thermoplastic resin layer 23 of the second exterior member 20 into opposition to each other and welding the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 around the embossed portion 45 to form the heat-sealed

portions

52a, 52 b. The battery cell chamber 42 is formed as a convex portion protruding outward of the exterior body from the heat-

seal portions

52a and 52b at a height equal to the height of the embossed portion 45, and the thickness of the assembly is large at the battery cell chamber 42 and small at the heat-

seal portions

52a and 52 b. In the battery cell chamber 42, a part of the first thermoplastic resin layer 13 is removed to form a first metal foil inner side exposed portion 14 to which the first metal foil 11 is exposed, and a part of the second thermoplastic resin layer 23 is removed to form a second metal foil inner side exposed portion 24 to which the second metal foil 21 is exposed.

One side of the first outer package 10 is formed as a first flange 15, the first flange 15 extends outward from the heat-sealed portion 52a, both surfaces of the first flange 15 form the outer surface of the outer package 32, and a first metal foil outer exposure portion 16 is formed to expose the first metal foil 11. On the other hand, a second flange 25 is formed on the side opposite to the first flange 15, the second flange 25 is formed by extending the second outer package 20 outward from the heat-sealed portion 52a, both surfaces of the second flange 25 constitute the outer surface of the outer package 32, and a second metal foil outer exposed portion 26 is formed by exposing the second metal foil 21. Further, the first metal foil outer side exposed portion 16 of the first flange 15 and the second metal foil outer side exposed portion 26 of the second flange 25 are perforated with 3 connection holes 17 and 27, respectively.

As shown in fig. 3, the battery element 60 sealed in the battery element chamber 42 together with the electrolyte is a wound-back type single cell, and a positive electrode 61, a separator 62, a negative electrode 63, and a separator 62 are laminated and the laminate is formed into a roll shape. In the battery element 60, the positive electrode 61 is exposed as the uppermost layer, and the negative electrode 63 is exposed as the lowermost layer. In the battery element chamber 42, the positive electrode 61 of the battery element 60 is in contact with and electrically conducted to the first metal foil inside exposed portion 14 of the first casing 10, and the negative electrode 63 is in contact with and electrically conducted to the second metal foil inside exposed portion 24 of the second casing 20. The first metal foil 11 is exposed at the first metal foil outer exposed portion 16 of the outer surface of the outer package 32, and the second metal foil 21 is exposed at the second metal foil outer exposed portion 26 of the outer surface of the outer package 32, so that the battery element 60 can be electrically conducted to the outside through the first metal foil 10 and the second metal foil 20. That is, the first metal foil 11 serves as a positive electrode-side conduction portion, and the second metal foil 21 of the second package 20 serves as a negative electrode-side conduction portion.

Battery pack

In the battery pack 5 shown in fig. 2A and 2B, 4 laminated power storage modules 2 are laminated and connected as follows: the first flanges 15 and the second flanges 25 of the adjacent modules in the stacking direction are alternately changed in direction so as to overlap, and the cell chambers 42 of the adjacent modules are overlapped. That is, in the 4 laminated power storage modules 2, the second metal foil outer exposed portion 26 of the second flange 25 of the uppermost module of the 1 st layer and the first metal foil outer exposed portion 16 of the first flange 15 of the 2 nd layer are connected by inserting the connecting pin 35 made of a conductive material into the connecting

holes

27 and 17, and similarly, the second metal foil outer exposed portion 26 of the module of the 2 nd layer and the first metal foil outer exposed portion 16 of the module of the 3 rd layer are connected to each other, and the second metal foil outer exposed portion 26 of the module of the 3 rd layer and the first metal foil outer exposed portion 16 of the module of the 4 th layer are connected to each other. In addition, 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 module of the layer 1, and a negative electrode pin 37 made of a conductive material is attached to the connection hole 27 of the second metal foil outer exposed portion 26 of the layer 4. By the above-described connection, 4 laminated power storage modules 2 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 drawn out and connected to other devices.

In the laminated power storage module 2, since the thickness of the module is thick in the cell element chamber 42 and is thin in the

heat seal portions

52a and 52b, a space 70 is formed between the laminated power storage modules 2 adjacent in the stacking direction. That is, a space 70 having a cross section of a square (the width of the heat-

seal lands

52a, 52b) x (the height of the embossed portion 45) is formed above the heat-

seal lands

52a, 52b on the periphery of the cell element chamber 42. Since the heat-

seal portions

52a and 52b are inevitably present around the cell compartments 42, all of the cell compartments 42 are in contact with the space 70 in the direction orthogonal to the stacking direction.

In the laminated power storage module 2, the plurality of battery elements 60 are electrically connected through the first metal foil 11 and the second metal foil 21 via the first metal foil inner exposed portion 14 and the second metal foil inner exposed portion 24, and the laminated power storage modules 2 can be connected to each other by the first metal foil outer exposed portion 16 and the second metal foil outer exposed portion 26. Further, the connection between the battery pack 5 and the external device is also made through the first metal foil outside exposed portion 16 and the second metal foil outside exposed portion 26. That is, the laminated electric storage module 2 and the battery pack 5 do not have tabs. Therefore, in the laminated electricity storage module 2, the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 are welded to each other at all the portions of the heat-

seal portions

52a and 52b connected to the cell element chamber 42, and therefore, the adhesion is good, the sealing property higher than that of the cell element chamber 42 from which the tab is drawn can be obtained, and the risk of liquid leakage can be reduced. Further, since no tab is used, the heat sealing operation is simple, and the battery pack 5 can be reduced in weight and space.

The battery pack 5 has a high capacity by connecting a plurality of the laminated power storage modules 2, and has a large amount of heat generated by the plurality of battery elements 60. In the battery pack 5, heat generated by the battery elements 60 is released into the space 70, and then cooling is performed by promoting heat dissipation using the gas flowing into the space 70. The space 70 is a heat dissipation space formed by laminating the laminated power storage modules 2, and can exhibit heat dissipation performance without using a heat dissipation member such as a corrugated member, and can obtain a cooling effect without increasing the size of the battery pack. The cooling by the space 70 is particularly effective in a structure in which a plurality of laminated power storage modules 2 are stacked, and cannot be achieved by using a single module. Further, when the battery capacity of the entire module is the same, the surface area of the module exterior body having the plurality of battery elements and the plurality of battery element chambers in which the battery elements are sealed is larger than that of a module having 1 battery element and 1 battery element chamber in which the battery elements are sealed, and the heat dissipation efficiency is high.

The cooling effect is improved by forcibly blowing air into the space 70, and can be further improved by blowing cold air. However, even if forced air blowing is not performed, natural convection occurs when a temperature difference occurs in the battery pack 5 due to a difference in the amount of heat generated, and a corresponding cooling effect can be obtained.

The battery pack is provided with a space formed by forming a battery cell chamber by an embossed portion and providing a convex portion on the outer surface of the outer package. However, the form of the embossed portion and the electrode element chamber is not limited to the embodiment shown in fig. 2A and 2B, and a convex portion may be formed on the outer surface of the package as long as the embossed portion is formed in at least one of the first package and the second package constituting the package. The distance between the battery element chambers, that is, the width of the heat seal portion is set to a size that can ensure the sealing performance of the battery element chambers, but the size of the heat seal portion may be increased to a larger size in order to increase the space for heat dissipation.

Fig. 4 and 5 show examples of other embodiments of the embossed portion and the cell compartment. In both figures, the laminated structure of the first and second

outer packages

10 and 20 and the internal structure of the battery cell chamber are omitted, and the laminated power storage module 2 is the same as the laminated power storage module 2 described above in that the first and second metal foil inner exposed portions are formed facing the inside of the chamber and the battery cell 60 is sealed therein.

The exterior body 80 of fig. 4 has embossed

portions

45 and 46 in both the first exterior body 10 and the second exterior body 20, and these

embossed portions

45 and 46 face each other to form one electrode element chamber 81. The exterior 82 of fig. 5 has embossed

portions

45 and 46 in both the first exterior 10 and the second exterior 20, and the

embossed portions

45 and 46 form

electrode element chambers

83a and 83b facing the flat portions of the facing members, respectively, as in the case of the exterior 80. Since the

embossed portions

45 and 46 are formed on both surfaces of the

exterior bodies

80 and 82 in the thickness direction, if a module including these

exterior bodies

80 and 82 is laminated, a space is formed on both surfaces of the module.

Further, the arrangement of the space can be changed depending on the lamination method of the laminated power storage module.

In the battery pack 6 shown in fig. 6, the laminated electric storage modules 2 are stacked with the positions of every other laminated electric storage module 2 shifted, and the center of the cell element chamber 42 of 1 module 2 is arranged to overlap the intersection of the heat-

seal portions

52a, 52b of the modules 2 adjacent thereto in the stacking direction. The offset amount is 1/2 of the distance between the cell compartments 42. When the position of the laminated power storage module 2 is shifted in this manner, the cell element chambers 42 are arranged in a staggered manner in the stacking direction. Since the displacement of the laminated power storage module 2 displaces the positions of the connection holes 17 and 27 of the adjacent modules, the widths of the first flange 15 and the second flange 25 are changed to align the connection holes 17 and 27. Therefore, strictly speaking, the shape of the laminated power storage module 2 shown in fig. 6 is different from that of the laminated power storage module 2 shown in fig. 1A to 2B, but the same reference numerals are used for simplifying the description and the drawings. In the battery pack 6, 4 laminated power storage modules 2 are connected in series by connecting pins 35, and a pin 36 for a positive electrode attached to the module of the 1 st layer and a pin 37 for a negative electrode attached to the module of the 4 th layer are used as electrode terminals of the battery pack 6, as in the battery pack 5.

In the above-described stacked structure, the spaces 71 are also formed in a staggered pattern in the stacking direction, and the spaces 71 are formed directly above and below the cell chambers 42 of the laminated power storage module 2 of each layer. The space 71 has the same size as the space 70 of the battery pack 5 described above, and is adjacent to the space 70 only in the direction orthogonal to the stacking direction with respect to the electrode element chamber 42 of the battery pack 5, and the electrode element chamber 42 of the battery pack 6 is adjacent to the space 71 in both the stacking direction and the direction orthogonal to the stacking direction. Therefore, the battery element chamber 42 is brought into contact with the space 71 in a larger area, and the cooling efficiency can be improved.

In the battery pack 6 in which the electrode element chambers 42 and the spaces 71 are arranged in a staggered manner as described above, the size relationship in the dimensions of the electrode element chambers 42 and the heat-

seal lands

52a, 52b is not limited because they are arranged in a staggered manner. When the electrode element chamber 42 and the heat-

seal lands

52a, 52b have the same size, a space having the same size as the electrode element chamber 42 is formed. When the electrode element chamber 42 is larger than the

heat seal portions

52a and 52b, the electrode element chamber 42 partially overlaps with each other in the stacking direction, but forms a space. Conversely, when the electrode element chamber 42 is smaller than the heat-

seal lands

52a, 52b, the heat-

seal lands

52a, 52b partially overlap in the stacking direction, but the electrode element chamber 42 on the lower layer supports the heat-

seal lands

52a, 52b on the upper layer, and therefore the electrode element chamber 42 on the upper layer does not enter the space and fill the space. In any case, a space corresponding to the size of the heat-

seal lands

52a, 52b can be formed.

As another means for improving the cooling effect, there is a method of providing a heat conductor 75 between the laminated power storage modules 2. In the battery pack 6 of fig. 6, a metal plate is interposed as the heat conductor 75 to discharge heat to the metal plate, thereby enhancing the cooling effect. The material of the heat conductor 75 is preferably aluminum or copper having high thermal conductivity, and a cooling device may be connected to the heat conductor 75 to improve the cooling effect.

Other embodiments of the laminated Electrical storage Module and Battery pack

The laminated electricity storage module constituting the battery pack is conditioned to have a metal foil outer exposed portion on the outer surface of the outer package, but the formation position thereof is not limited. The outer metal exposed portion is a portion where conduction between the modules and conduction between the battery pack and the outside are obtained, and conduction between them can be achieved also in the outer metal foil exposed portion provided outside the flange.

The laminated

power storage modules

2a, 2b, 2C, and 2d constituting the battery pack 7 having the 4-layer structure shown in fig. 7A to 7C are similar to the laminated power storage module 2 constituting the battery pack 6 in that the positive electrode 61 of the battery element 60 is electrically connected to the first metal foil inner side exposed portion 14 and the negative electrode 63 is electrically connected to the second metal foil inner side exposed portion 24 in the battery element chamber 42, but the formation position of the metal foil outer side exposed portion where the metal foil is exposed on the outer surface of the outer package 33 differs depending on the lamination position. Further, the 4 laminated type

electric storage modules

2a, 2b, 2c, 2d are the same as the battery pack 6 in that they are laminated in such a manner that the cell element chambers 42 and the spaces 71 are arranged in a staggered pattern in the lamination direction.

In the uppermost layer 1-st laminated power storage module 2a, the first metal foil outer exposure portion 16 is formed on the first flange 15. As shown in fig. 7B, the second metal foil outer exposure portion 28 is formed on the surface opposite to the second metal foil inner exposure portion 24, that is, on the bottom surface of the battery element chamber 42. The second metal foil outer exposure portion 28 is formed by removing the second heat-resistant resin layer 22 of the second package 20 to expose the second metal foil 21.

In the laminated power storage modules 2b and 2C having the intermediate 2 nd and 3 rd layers, as shown in fig. 7C, the first metal foil outer exposed portion 18 is formed on the surface opposite to the first metal foil inner exposed portion 14, that is, the top surface of the cell element chamber 42. The first metal foil outer exposure portion 18 is formed by removing the first heat-resistant resin layer 12 of the first external device 10 to expose the first metal foil 11. Further, as shown in fig. 7B, the second metal foil outer exposure portion 28 is formed on the surface opposite to the second metal foil inner exposure portion 24, that is, the bottom surface of the battery element chamber 42. The second metal foil outer exposure portion 28 is formed by removing the second heat-resistant resin layer 22 of the second package 20 to expose the second metal foil 21.

In the laminated power storage module 2d of the 4 th layer as the lowermost layer, as shown in fig. 7C, the first metal foil outer exposed portion 18 is formed on the surface opposite to the first metal foil inner exposed portion 14, that is, the top surface of the cell element chamber 42. The first metal foil outer exposure portion 18 is formed by removing the first heat-resistant resin layer 12 of the first external device 10 to expose the first metal foil 11. Further, a second metal foil outer exposure portion 26 is formed at the second flange 25.

In the battery pack 7, the 3 kinds of 4 laminated

power storage modules

2a, 2b, 2c, and 2d are stacked with a heat conductor 75 made of a conductive material interposed therebetween, and the stacked body is sandwiched by a jig (not shown) to be assembled by bringing the heat conductor 75 and the laminated

power storage modules

2a, 2b, and 2c into close contact with each other. In this assembled state, the first metal foil outer exposure portion 18 and the second metal foil outer exposure portion 28 formed on the outer surface of the battery element chamber 42 are in contact with the heat conductor 75. Since the heat conductor 75 is an electrical conductor, the battery elements 60 of the respective layers are connected in series via the first metal foil 10 and the second metal foil 20. Further, the current is passed to the external device through the first metal foil outer exposed portion 16 of the first flange 15 of the uppermost laminated module 2a and the second metal foil outer exposed portion 26 of the second flange 25 of the lowermost laminated power storage module 2c, and the positive electrode pin 36 and the negative electrode pin 37 are attached to these portions.

As described above, the metal foil external exposure portion is provided at the contact portion of the laminated multilayer power storage module, and the connection of the multilayer power storage module can be realized without using a connecting member. In the battery pack 7, the heat conductor 75 is interposed to improve the cooling effect, and the heat conductor 75 is used as the conductive portion, but the metal foil exposed portions may be directly brought into contact with each other without interposing the heat conductor 75 therebetween to achieve conduction.

Material and shaping of first and second outer parts

In the first package 10, a first heat-resistant resin layer 12 is bonded to one surface of a first metal foil 11 via a first adhesive layer, and a first thermoplastic resin layer 13 is bonded to the other surface via a second adhesive layer. The first metal foil inside exposed portion 14 is formed by removing the first thermoplastic resin layer 13 and the second adhesive layer, and the first metal foil outside exposed

portions

16, 18 are formed by removing the first thermoplastic resin layer 13 and the second adhesive layer or removing the first heat-resistant resin layer 12 and the first adhesive agent corresponding to the surface to be formed. Further, in the case of forming the embossed portion 45 by press forming, after forming the metal exposed portion, press forming is performed.

The second package 20 has a second heat-resistant resin layer 22 bonded to one surface of the second metal foil 21 via a third adhesive layer, and a second thermoplastic resin layer 23 bonded to the other surface via a fourth adhesive layer. Like the first external member 20, the second metal foil inner side exposed portion 24 is formed by removing the second thermoplastic resin layer 23 and the fourth adhesive layer, and the second metal foil outer side exposed

portions

26, 28 are formed by removing the second thermoplastic resin layer 23 and the fourth adhesive layer or the second heat-resistant resin layer 22 and the third adhesive layer corresponding to the surface to be formed.

In fig. 1B, 2B, 6, 7B, and 7C, the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer are not shown.

The first metal foil 11 is preferably made of a soft aluminum foil and preferably has a thickness of 20 to 150 μm. From the viewpoint of moldability and cost, a soft aluminum foil of 30 μm to 80 μm is particularly preferable. On the other hand, the preferred material of the second metal foil 21 is soft or hard aluminum foil, stainless steel foil, nickel foil, copper foil, or titanium foil. The thickness of these foils is preferably 10 to 150. mu.m, and from the viewpoint of impact resistance, bending resistance and cost, it is preferably 15 to 100. mu.m.

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

Further, it is preferable that chemical conversion coatings be formed on the first metal foil layer 11 and the second metal foil layer 21 on at least the surfaces on the sides where the metal foil exposed

portions

14, 16, 24, and 26 exist. The chemical conversion coating is formed by performing chemical conversion treatment on the surface of the metal foil, and by performing such chemical conversion treatment, corrosion of the contained substance (electrolyte, etc.) on the surface of the metal foil can be sufficiently prevented, and even if the electrolyte adheres to the exposed portion constituting the electricity extraction window during the production of the module, discoloration and deterioration do not occur, and the influence of corrosion of moisture in the atmosphere, etc. can be reduced. The chemical conversion treated layer itself has substantially no conductivity, the coating film thickness is extremely small, and the electrical resistance is substantially absent. For example, the metal foil is subjected to the chemical conversion treatment by performing the following treatment. That is, an aqueous solution of any one of the following items 1) to 3) is applied to the surface of the degreased metal foil, and then dried to perform chemical conversion treatment

1) An aqueous solution comprising phosphoric acid, chromic acid, and a mixture of at least one compound selected from the group consisting of metal salts of fluoride and non-metal salts of fluoride;

2) an aqueous solution comprising a mixture of phosphoric acid, at least 1 resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenol resins, and at least 1 compound selected from the group consisting of chromic acid and chromium (III) salts;

3) an aqueous solution comprising a mixture of phosphoric acid, at least 1 resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenol resins, at least 1 compound selected from the group consisting of chromic acid and chromium (III) salts, and at least 1 compound selected from the group consisting of metal salts of fluorides and non-metal salts of fluorides

The amount of chromium deposited on the chemical conversion coating (per single surface) is preferably 0.1mg/m²～50mg/m²Particularly preferably 2mg/m²～20mg/m²。

As the heat-resistant resins constituting the first heat-resistant resin layer 12 and the second heat-resistant resin layer 22, heat-resistant resins that are not melted at the heat-sealing temperature used for heat-sealing of exterior parts are used. As the heat-resistant resin, a heat-resistant resin having a melting point higher than the melting points of the thermoplastic resins constituting the first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 by 10 ℃ or more is preferably used, and a heat-resistant resin having a melting point higher than the melting point of the thermoplastic resin by 20 ℃ or more is particularly preferably used. For example, stretched films such as polyethylene naphthalate films, polybutylene naphthalate films, and polycarbonate films are preferable in addition to polyester films and polyamide films. The thickness is preferably in the range of 9 to 50 μm.

The first thermoplastic resin layer 13 and the second thermoplastic resin layer 23 are preferably inextensible films made of at least 1 thermoplastic resin selected from the group consisting of polyethylene, polypropylene, olefin copolymers, acid-modified products thereof, and ionomers, and preferably have a thickness in the range of 20 to 80 μm.

The first adhesive layer and the third adhesive layer are preferably two-component curable polyester urethane adhesives or polyether urethane adhesives, and the second adhesive layer and the fourth adhesive layer are preferably polyolefin adhesives in view of electrolyte resistance. The preferred coating of each adhesive is 1g/m²～5g/m²。

The method of forming the exposed portion of the metal foil in the first and second

exterior members

10 and 20 is not limited in any way. For example, in the step of bonding the metal foil and the resin layer by the dry lamination method, the adhesive is applied using a gravure roll in which the portion to which the adhesive is not attached is engraved to form an adhesive-uncoated portion, and after bonding the metal foil and the resin layer, the resin layer on the adhesive-uncoated portion is cut off to expose the metal foil. The first and second

exterior devices

10, 20 used in the laminated power storage module 2 of the above embodiment have the metal foil exposed

portions

14, 16, 24, 26 on the thermoplastic resin layer side surfaces, and the first metal foil 11 and the first thermoplastic resin layer 13, and the second metal foil 21 and the second thermoplastic resin layer 23 are bonded together by the above method, and then the metal foil exposed

portions

14, 16, 24, 26 are formed. On the other hand, since there is no metal exposed portion on the side of the heat-resistant resin layer, 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 can be bonded using a well-known method.

In the case where the metal foil outer exposed portion is formed on the surface of the first external member 10 on the side of the first heat-resistant resin layer 12 and/or on the surface of the second external member 20 on the side of the second heat-resistant resin layer 22, 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 are bonded by the above-described method, and then the resin layers are removed.

In addition, as shown in fig. 1A and the like, in the case where the embossed portion 45 is formed by press-forming the first external member 10, the metal exposed portion is formed and then the press-forming is performed. In the forming of the first external package 10 of the illustrated example, the press forming is performed by using a forming die including a male die into which the first metal foil inside exposed portion 14 is brought into contact with the top surface, a female die into which the male die is inserted, and a pressing die. The second outer package 20 is also press-formed in the same manner as the case where the embossed portion is formed.

Further, if the first outer package 10 is cut in such a size that both sides without the first flange protrude a little from the second outer package 20, and the protruding portions are heat-sealed and then bent, the first metal foil 11 and the second metal foil 21 can be prevented from contacting at the cut end surfaces. It is also possible to reverse the dimensions of the first and second

outer packages

10, 20 and bend the second outer package 20.

Construction and materials for battery elements

The laminated

power storage modules

2, 2a, 2b, 2c, and 2d use a single cell as the battery element 60. Details of the battery cell and the electrolyte sealed together with the battery cell are as follows.

(Single battery)

The battery cell as the battery element 60 is composed of a positive electrode 61, a separator 62, and a negative electrode 63. The embodiment of the battery cell is not limited to the rewind type of fig. 3. As another embodiment of the unit cell, a lamination type in which the positive electrode and the negative electrode are cut into the size of a cell, a separator is formed for each foil, and then a plurality of the separators are alternately laminated may be exemplified, and the collectors of the positive electrode and the collectors of the negative electrode are bonded to each other by ultrasonic waves.

The positive electrode 61 is preferably composed of a current collector and a positive electrode active material, and a metal foil is generally used as the current collector. The metal foil is preferably a hard or soft aluminum foil having a thickness of 7 to 50 μm, and the portion in contact with the metal exposed portion 14 is preferably free of active material. The composition of the positive electrode active material layer is not particularly limited, and the positive electrode active material layer is formed of, for example, a mixed composition in which a lithium salt (for example, lithium cobaltate, lithium nickelate, lithium iron phosphate, lithium manganate, or the like) is added to a binder such as PVDF (polyvinylidene fluoride), SBR (styrene butadiene rubber), CMC (sodium carboxymethylcellulose), PAN (polyacrylonitrile), or a linear polysaccharide. The thickness of the positive electrode active material layer is preferably set to 2 to 300 μm. The positive electrode active material layer may further contain a conductive auxiliary such as carbon black or CNT (carbon nanotube).

In addition, a binder is preferably used between the current collector and the positive electrode active material in order to improve adhesion. The binder is not particularly limited, and examples thereof include layers made of PVDF, SBR, CMC, PAN, linear polysaccharides, and the like. In the binder layer, a conductive aid such as carbon black or CNT (carbon nanotube) may be further added to improve the conductivity between the current collector and the positive electrode active material layer. The thickness of the adhesive layer is preferably set to 0.2 to 10 μm. By setting the adhesive layer to 10 μm or less, an increase in the internal resistance of the battery cell formed of the adhesive having no conductivity can be suppressed as much as possible.

The negative electrode 63 is preferably composed of a current collector, which is generally made of a metal foil, and a negative electrode active material. The metal foil is preferably a copper foil having a thickness of 7 to 50 μm, and aluminum foil, titanium foil, or stainless steel foil may be used. In addition, as in the positive electrode, it is preferable that no active material is present in a position in contact with the metal exposed portion 24. The composition of the negative electrode active material layer is not particularly limited, and for example, the negative electrode active material layer is formed from a mixed composition in which an additive (for example, graphite, lithium titanate, Si-based alloy, tin-based alloy, or the like) is added to a binder such as PVDF, SBR, CMC, PAN, or linear polysaccharide. The thickness of the negative electrode active material layer is preferably set to 1 μm to 300 μm. The negative electrode active material layer may further contain a conductive auxiliary such as carbon black or CNT (carbon nanotube).

In addition, a binder is preferably used between the current collector and the negative electrode active material in order to improve adhesion. The binder is not particularly limited, and examples thereof include layers made of PVDF, SBR, CMC, and PAN. In the binder layer, a conductive aid such as carbon black or CNT may be further added to improve the conductivity between the current collector and the negative electrode active material layer. The thickness of the adhesive layer is preferably set to 0.2 to 10 μm. By setting the adhesive layer to 10 μm or less, an increase in the internal resistance of a cell formed of an adhesive having no conductivity can be suppressed as much as possible.

When the binder layer and the positive electrode active material layer are laminated on the current collector (metal foil) constituting the positive electrode 61, the respective layer compositions are sequentially applied to the metal foil and dried. The same applies to the case where the binder layer and the negative electrode active material layer are laminated on the current collector (metal foil) constituting the negative electrode 63.

The separator 62 is not particularly limited, and examples thereof include a polyethylene separator, a polypropylene separator, a separator formed of a laminated film of a polyethylene film and a polypropylene film, and a separator formed of a wet or dry porous film obtained by coating a heat-resistant inorganic material such as ceramic on the resin separator. The thickness of the separator 62 is preferably set to 5 μm to 50 μm.

In addition, when the laminated storage module of the present invention is an electric double layer capacitor, preferable materials are as follows.

The current collector of the positive electrode 61 and the current collector of the negative electrode 63 are preferably hard aluminum foils having a thickness of 7 to 50 μm. The positive electrode active material and the negative electrode active material are preferably carbon black or CNT (carbon nanotube). The separator is preferably a porous cellulose film having a thickness of 5 to 100 μm, a nonwoven fabric having a thickness of 5 to 100 μm, or the like.

(electrolyte)

The electrolyte sealed together with the battery element is not particularly limited, and examples thereof include an electrolyte containing a solvent selected from at least one of water, ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and dimethoxyethane, and a lithium salt. The lithium salt is not particularly limited, and examples thereof include lithium hexafluorophosphate, lithium tetrafluoroborate, quaternary ammonium tetrafluoroborate, and the like. Examples of the quaternary ammonium salt include tetramethylammonium salt and the like. In addition, as the electrolyte, a substance gelled with PVDF, PEO (polyethylene oxide), or the like can be used.

Method for manufacturing laminated electricity storage module and battery pack

The laminated

power storage modules

2, 2a, 2b, 2c, and 2d can be manufactured by the following steps.

(1) By the method described above, the first exterior device 10 is produced in which the first metal foil inner side exposed portion 14, the first metal foil outer side exposed portion 16 or the first metal foil exposed portion 18, and the embossed portion 45 are formed at desired positions. Further, a second package 20 in which a second metal foil inner exposed portion 24, a second metal foil outer exposed portion 26, or a second metal foil outer exposed portion 28 is formed at a desired position is manufactured.

(2) The first package 10 is placed so that the first thermoplastic resin layer 13 faces upward, the battery element 60 is loaded so that the positive electrode 61 of the battery element 60 is in contact with the first metal foil inside exposed portion 14 in each embossed portion 45 constituting the battery element chamber 42, and the electrolyte is injected using a syringe or the like.

(3) The

outer cases

32 and 33 are assembled by positioning and overlapping the second outer case 20 so that the second metal foil inner exposed portion 24 of the second outer case 20 is in contact with the negative electrode 63 of the battery element 60. In this assembled state, the first flange 15 extends from the end of the second package 20, the second flange 25 extends from the end of the first package 10, and the first metal foil outer exposed portion 16 and the second metal foil outer exposed portion 26 are exposed to the outer surfaces of the

outer cases

32 and 33.

(4) The heat-seal lands 52a are formed using a hot plate heated.

(6) The electric clamps were connected to the first metal foil outer exposed portion 16 of the first flange 15 and the second metal foil outer exposed portion 26 of the second flange 25, and pre-charged, placed in a 100 ℃ thermostat for 8 hours, and exhausted.

(7) The unsealed portion is heat-sealed with a heated hot plate under a reduced pressure environment to form a heat-sealed portion 52b, thereby sealing the battery element 60 and the electrolyte in the cell element chamber 42.

(8) Connection holes 17 and 27 are formed in the first metal foil outer exposed portion 16 of the first flange 15 and the second metal foil outer exposed portion 26 of the second flange 25.

The above-described production method is merely an example, and such a production method should not be particularly limited.

A desired number of the produced laminated

power storage modules

2, 2a, 2b, 2c, 2d are stacked, or a desired number of the produced laminated

power storage modules

2, 2a, 2b, 2c, 2d are stacked via the heat conductor 75, and the modules adjacent in the stacking direction are connected by the above-described method to assemble a battery pack. The number of layers stacked in the battery pack of the present invention is arbitrary.

The battery pack of the present invention can be used for a power source for automobiles, bicycles, motorcycles, trains, airplanes, ships, and the like, which require electricity, and more specifically, can be used for a large-capacity lithium secondary battery (lithium ion battery, lithium polymer battery, or the like) module, a solid-state battery module, a lithium ion capacitor module for the same purpose, and an electric double layer capacitor module for the same purpose, such as a hybrid automobile, an electric automobile, an industrial-household secondary battery, and the like.

Examples

Next, specific examples of the present invention will be described, and the present invention is not particularly limited to these examples.

(example 1)

4 of the laminate type modules 2 shown in fig. 1A and 1B were prepared, and the battery pack 5 shown in fig. 2A and 2B was prepared.

The first metal foil 11 was a soft aluminum foil of a8079 type classified according to JIS H4160 and having a thickness of 40 μm, and chemical conversion treatment was performed on both surfaces. The first heat-resistant resin layer 12 is a biaxially stretched polyamide film having a thickness of 25 μm. The first thermoplastic resin layer 13 is an unstretched polypropylene film having a thickness of 40 μm. The second metal foil 21 was a soft SUS304 stainless steel foil with a thickness of 20 μm, and chemical conversion treatment was performed on both surfaces. The second heat-resistant resin layer 22 is a biaxially stretched polyester film having a thickness of 12 μm. The second thermoplastic resin layer 23 is an unstretched polypropylene film having a thickness of 40 μm.

Further, the dimensions of the first metal foil inside exposed portion 14 and the second metal foil inside exposed portion 24 are 30mm × 30mm, and the dimensions of the first metal foil outside exposed portion 16 and the second metal foil outside exposed portion 26 are 20mm × 200 mm.

(first outer package)

The first heat-resistant resin layer 12 was bonded to one surface of the first metal foil 11 by a dry lamination method using a two-pack curable polyester urethane adhesive having a coating thickness of 3 μm, and cured in an aging oven at 50 ℃ for 3 days. Next, when a two-pack curable olefin adhesive was applied to the reverse surface of the first metal foil 11 by a dry lamination method to a coating thickness of 2 μm, adhesive uncoated portions corresponding to the size and position of 9 first metal foil inner exposed portions 14 and 1 first metal foil outer exposed portion 16 were formed, and the first thermoplastic resin layer 13 was bonded. After the adhesion, the resultant was aged in an aging oven at 40 ℃ for 3 days.

After the curing, the first thermoplastic resin layer 13 on the adhesive-removed uncoated portion is cut off by a laser cutter, and a first metal foil inner exposed portion 14 and a first metal foil outer exposed portion 16, from which the first metal foil 11 is exposed, are formed.

Next, a forming die having a 40mm square shape and composed of a male die, a female die, and a pressing die was used, and press forming was performed with a pressing depth of 4mm in a state where the top surface of the male die was in contact with the first metal foil inside exposed portion 14, thereby forming an embossed portion constituting the cell element chamber 42. Then, the periphery is trimmed to obtain the first external fitting 10. The planar dimensions of the first outer fitting 10 are 140mm x 160 mm.

(second housing)

The second heat-resistant resin layer 22 was bonded to one surface of the second metal foil 21 by a dry lamination method using a two-pack curable polyester urethane adhesive having a coating thickness of 3 μm, and cured in an aging oven at 50 ℃ for 3 days. Next, when a two-pack curable olefin adhesive was applied to the reverse surface of the second metal foil 21 to a thickness of 2 μm by dry lamination, adhesive-uncoated portions corresponding to the size and position of 9 second-metal-foil inner exposed portions 24 and 1 second-metal-foil outer exposed portion 26 were formed, and the second thermoplastic resin layer 23 was bonded. After the adhesion was made, aging was carried out in an aging oven at 40 ℃ for 3 days.

After the curing, the second thermoplastic resin layer 23 on the adhesive-removed uncoated portion is cut off by a laser cutter, and a second metal foil inner exposed portion 24 and a second metal foil outer exposed portion 26, from which the second metal foil 21 is exposed, are formed. And then trimmed around to provide a second outer package 20. The second outer package 20 has planar dimensions of 150mm x 160mm, which are larger than the first outer package 10.

(electrode element)

As the electrode element 60, a single cell was produced using the following materials.

The current collector of the positive electrode 61 was a hard aluminum foil of A1100 classified according to JIS H4160, and had a thickness of 15 μm and a width of 500 mm. The current collector of the negative electrode 63 was a hard copper foil of C1100R classified according to JIS H3100, and had a thickness of 15 μm and a width of 200 mm. The paste for forming a positive electrode active material layer was a paste obtained by kneading and dispersing 60 parts by mass of a positive electrode active material containing lithium cobaltate as a main component, 10 parts by mass of PVDF as a binder and an electrolyte retaining agent, 5 parts by mass of acetylene black (a conductive material), and 25 parts by mass of N-methyl-2-pyrrolidone (an organic solvent). The paste for forming a negative electrode active material was obtained by kneading 57 parts by mass of a negative electrode active material containing carbon powder as a main component, 5 parts by mass of PVDF as a binder and an electrolyte retaining agent, 10 parts by mass of a copolymer of hexafluoropropylene and maleic anhydride, 3 parts by mass of acetylene black (a conductive material), and 25 parts by mass of N-methyl-2-pyrrolidone (an organic solvent) and dispersing them. The binder solution is obtained by dissolving PVDF in a solvent (dimethylformamide). The separator 62 was a porous wet separator having a width of 38mm and a thickness of 8 μm. The electrolyte was a solution obtained by dissolving lithium hexafluorophosphate (LiPF6) at a concentration of 1 mol/l in a mixed solvent obtained by mixing Ethylene Carbonate (EC), dimethyl carbonate (DMC) and Ethyl Methyl Carbonate (EMC) at an equivalent volume ratio.

The positive electrode 61 is produced by the following steps. First, a binder solution was applied to the entire surface of one surface of the current collector, and the whole was dried at 100 ℃ for 30 seconds to form a binder layer having a thickness of 0.5 μm after drying. Next, a positive electrode active material layer liquid paste was applied to the surface of the pressure-sensitive adhesive layer, dried at 100 ℃ for 30 minutes, and then hot-pressed to form a positive electrode active material layer liquid paste having a density of 4.8g/cm³And a dried positive electrode active material layer having a thickness of 120 μm. Then, the resultant was cut into a coil shape having a width of 35mm by a width-providing step.

The negative electrode 63 is produced by the following steps. First, a binder solution was applied to one surface of a current collector, and dried at 100 ℃ for 30 seconds to form a binder layer having a thickness of 0.5 μm after drying. Then, a negative electrode active material layer liquid composition paste was applied to the surface of the binder layer, dried at 100 ℃ for 30 minutes, and then hot-pressed to form a negative electrode active material layer liquid composition having a density of 1.5g/cm³And a negative electrode active material layer having a thickness of 20.1 μm after drying. Then, the resultant was cut into a coil shape having a width of 35mm by a width-providing step.

Next, the negative electrode 63 (current collector-negative electrode active material layer)/separator 62/(positive electrode active material layer-current collector) and the positive electrode 61/separator were stacked in this order with a slight shift between them, and rolled up so that the positive electrode 61 was exposed on one surface and the negative electrode 63 was exposed on the opposite surface, thereby producing a 38mm square cell having a thickness of 4 mm.

(Assembly of laminated Electricity storage Module and Battery pack)

(1) The first package 10 is placed with the first thermoplastic resin layer 13 facing upward, the battery element 60 is loaded so that the positive electrode 61 of the battery element 60 is in contact with the first metal foil inside exposed portion 14 in each embossed portion 45 for forming the battery element chamber 42, and the electrolyte is injected using a syringe or the like.

(2) The package 32 is assembled by positioning and overlapping the second package 20 so that the second metal foil inner exposed portion 24 of the second package 20 is in contact with the negative electrode 63 of the battery element 60. In this assembled state, the first flange 15 extends from the end portion of the second exterior member 20, the second flange 25 extends from the end portion of the first exterior member 10, and the first metal foil outer exposure 16 and the second metal foil outer exposure 26 are exposed on the outer surface of the exterior body 32.

(3) The heat-sealed portion 52a was formed by heat-sealing at a pressure of 0.3MPa for 3 seconds using a hot plate heated to about 200 ℃. The width of the heat-seal land 52a between the embossed portions 45 was 5 mm.

(4) An electric clip was connected to the first metal foil outer exposed portion 16 of the first flange 15 and the second metal foil outer exposed portion 26 of the second flange 25, charged until a cell voltage of 4.2V was generated, and placed in a thermostatic bath at 100 ℃ for 8 hours to vent the inside of the cell compartment 42.

(5) The unsealed portion was heat sealed with a hot plate heated to about 200 ℃ under a reduced pressure of 86kPa to form a heat-sealed portion 52b, thereby sealing the battery element 60 and the electrolyte into the cell chamber 42. The width of the heat-seal land 52b between the embossed portions 45 was 5 mm.

(6) As a countermeasure against the short circuit, an adhesive tape of 25 μm is attached to the end edge on the second flange 25 side of the first outer package 10 and the end edge on the first flange 15 side of the second outer package 20, and covers the first metal foil 11 and the second metal foil 21 exposed at the end surfaces. In addition, the second outer package 20 extending out is bent toward the first outer package 10 on the other 2 sides, so that measures against insulation are taken, and the strength of the side surface is enhanced. Fig. 2A shows a state before bending.

(7) 3 connection holes 17 and 27 are punched in the first metal foil outer exposed portion 16 of the first flange 15 and the second metal foil outer exposed portion 26 of the second flange 25.

By the above steps, 4 laminated power storage modules 2 were produced.

(8) Referring to fig. 2A and 2B, the 4 laminated type modules 2 are changed in direction so as to be different from each other and laminated in such a manner that the first flange 15 and the second flange 25 of the modules adjacent in the laminating direction coincide with each other.

(9) The 4 laminated modules 2 are connected in series by the connecting pin 35, the positive electrode pin 36 is attached to the uppermost first metal foil outer exposed portion 16, and the negative electrode pin 37 is attached to the lowermost second metal foil outer exposed portion 26. The battery pack 5 is manufactured by the above-described steps.

The battery pack 5 has a quadrangular space 70 having a cross section of (5 mm width of the heat-seal land 52 a) × (4 mm height of the embossed portion) formed above the heat-seal land 52a, and a quadrangular space having a cross section of (5 mm width of the heat-seal land 52b) × (4 mm height of the embossed portion) formed above the heat-seal land 52 b.

Comparative example 1

Comparative example 1 is a battery pack in which 4 laminated power storage modules different in structure from example 1 were laminated.

In the laminated electricity storage module 2 of example 1, the 9 battery elements 60 are sealed in the respective battery element chambers 42, and the metal foil exposed portions are formed on the inner surface and the outer surface of the outer package, whereby the conduction with the battery elements 60 can be achieved without using tabs. The laminated battery module of comparative example 1 was configured such that 1 cell element was sealed in 1 cell element chamber, and the size of the cell element was increased to obtain the same capacity as the 9 cell elements of example 1, as compared with the laminated battery module 2. In the laminate type module of comparative example 1, the outer package was not provided with the exposed metal foil portions on the inner and outer sides, and the tab was connected to the battery element and led out of the outer package.

(outer body)

In the exterior device, a portion having an embossed portion constituting a battery cell chamber corresponding to the first exterior device 10 of example 1 and a flat portion having an opening portion for closing the embossed portion corresponding to the second exterior device 20 of example 1 are integrated. The exterior body is formed by folding the exterior body into two layers. The material constituting the outer package is a flexible aluminum foil (A8021 flexible aluminum foil classified according to JIS H4160) having a thickness of 40 μm, a biaxially stretched polyamide film having a thickness of 25 μm, a thermoplastic resin layer, or a polypropylene film having a thickness of 40 μm, if the material is a metal foil, or the material is a heat-resistant resin layer.

The outer fittingThe coating weight was 3g/m on the entire surface of one side of the metal foil²The heat-resistant resin layer is bonded with the polyester urethane adhesive, and the coating weight on the whole of the other surface is 2g/m²The thermoplastic resin layer was bonded with the polyolefin adhesive, and the cured product was cured in a thermostatic bath at 40 ℃ for 3 days. The outer package has no metal foil exposed portion, and the aluminum foil is entirely covered with a resin layer.

The outer package was press-molded to form an embossed portion of 115mm × 115mm × 4mm in height, and the flat portion and the portion to be heat-sealed were trimmed to the dimensions.

(Battery element and tab)

The battery element was fabricated by forming a rectangular shape having an outer shape of 110mm on a side using the same material as in example 1.

The positive electrode tab was produced by heat-sealing an insulating film of a maleic anhydride-modified polypropylene film (melting point 140 ℃ C., MFR 3.0g/10 min) having a length of 10mm, a width of 5mm and a thickness of 50 μm on both sides of an aluminum foil so that one end side in the longitudinal direction of a soft aluminum foil (A1050 soft aluminum foil classified according to JIS H4000) having a length of 30mm, a width of 3mm and a thickness of 100 μm was exposed for 5 mm.

The negative electrode tab was produced by heat-sealing an insulating film of a maleic anhydride-modified polypropylene film (melting point 140 ℃ C., MFR 3.0g/10 min) having a length of 10mm, a width of 5mm and a thickness of 50 μm on both surfaces of a nickel foil with the nickel foil interposed therebetween so that one end side in the longitudinal direction of the nickel foil having a length of 40mm, a width of 3mm and a thickness of 100 μm was exposed to 5 mm.

And the positive pole of the battery element is jointed with the end part of the positive pole lug, the negative pole of the battery element is jointed with the negative pole lug, and the top ends of the positive pole lug and the negative pole lug are led out from the same side of the battery element.

(Assembly of laminated Electricity storage Module and Battery pack)

(1) The exterior component is marked with a scale or the like in advance.

(2) The battery element is loaded in the embossed portion of the package, the external package is aligned so that the insulating film of the tab is placed on the portion to be heat-sealed, and the flat portion is folded at the position where the mark is formed so as to cover the embossed portion.

(3) 2 sides including the side from which the tab was pulled out were held by a hot plate heated to 200 ℃ under a pressure of 0.3MPa, and heat-sealed for 3 seconds.

(4) From the unsealed side, 45mL of the same electrolyte as in example 1 was injected using a syringe, and pre-charging and air-discharging were performed in the same manner as in example 1.

(5) The cell element and the electrolyte were sealed in a cell element chamber by heat-sealing the unsealed side for 3 seconds at a pressure of 0.3MPa while holding the unsealed side in a discharged state of 3.0V and under a reduced pressure of 0.086MPa using a hot plate heated to 200 ℃.

Through the above steps, 4 laminated power storage modules were produced.

(6) The battery pack was assembled by stacking 4 laminated modules and connecting them in series.

Evaluation of

The battery packs of example 1 and comparative example 1 obtained by the above-described treatment were evaluated by the following evaluation method. The evaluation results are shown in table 1.

After the battery was fully charged to 16.8V, 1C charge and discharge (1 hour charge, 1 hour discharge) was repeated 100 times at room temperature of 18 ℃. When the fully charged battery was discharged at 1C, the temperature at 0.2C was measured by a temperature sensor, and the average value was obtained. The temperature measurement position was at the center of the module of layer 3 in both example 1 and comparative example 1, with example 1 being at the center of the outer surface of the embossed portion in the center of 3 rows × 3 columns, and comparative example 1 being at the center of the embossed portion.

[ TABLE 1 ]

As shown in table 1, no difference was observed in the battery capacity between example 1 and comparative example 1, and the same results were obtained even when charging and discharging were repeated for 100 cycles. Further, it was confirmed that the battery pack of example 1 had a good heat dissipation effect because the amount of heat generated during discharge was suppressed, compared to comparative example 1, regardless of whether the battery pack was discharged at 1C or 0.2C.

This application claims the priority of Japanese patent application No. 2015-83102 applied on 4/15/2015, and the contents of the description are directly included in the content of this application.

It must be understood that the words and expressions used herein are words and expressions of description and not of limitation, and that there is no intention, in the use of such equivalents, of the features shown and described herein, and it is recognized that various modifications are possible within the scope of the invention claimed.

Industrial applicability

The laminated electric storage module of the present invention can be suitably used as various power sources.

Claims

1. A battery pack characterized in that a battery pack is provided,

a laminated power storage module is provided with: a first exterior member in which a first heat-resistant resin layer is laminated on one surface of a first metal foil, a first thermoplastic resin layer is laminated on the other surface, and a first metal foil inner-side exposed portion that exposes the first metal foil is provided on the surface on the first thermoplastic resin layer side; a second exterior member in which a second heat-resistant resin layer is laminated on one surface of a second metal foil, a second thermoplastic resin layer is laminated on the other surface, and a second metal foil inner side exposed portion that exposes the second metal foil is provided on the surface on the second thermoplastic resin layer side; a battery element having a positive electrode, a negative electrode, and a separator disposed therebetween,

at least one of the first exterior member and the second exterior member has an embossed portion in a region including a first metal foil inner exposed portion and a second metal foil inner exposed portion, the first thermoplastic resin layer of the first exterior member and the second thermoplastic resin layer of the second exterior member are opposed to each other and surrounded by a heat-seal portion obtained by welding the first thermoplastic resin layer and the second thermoplastic resin layer, thereby forming an exterior body having a plurality of battery element cells, the battery element cells being formed into convex portions by the embossed portions, the first metal foil inner exposed portion and the second metal foil inner exposed portion facing each other in a cell,

in the outer package, one side of the first outer package extends from the heat-sealed portion, a first flange having two surfaces constituting an outer surface of the outer package is formed, a first metal foil outer exposed portion exposing the first metal foil is formed on the first flange, and a connecting hole is punched in the first metal foil outer exposed portion,

one side of the second outer package extends from the heat-sealed portion, a second flange is formed, two surfaces of which constitute the outer surface of the outer package, a second metal foil outer exposed portion is formed on the second flange so as to expose the second metal foil, and a connecting hole is punched in the second metal foil outer exposed portion,

the plurality of laminated power storage modules are laminated so as to form a space above the heat-sealed portion, and the first metal foil outer exposed portion and the second metal foil outer exposed portion of the laminated power storage modules adjacent to each other in the laminating direction are electrically connected to each other via a connecting pin inserted into the connecting hole.

2. The battery pack according to claim 1,

a plurality of laminated power storage modules are laminated such that the cell element chambers and the heat-sealed portions are overlapped in the lamination direction of the laminated power storage modules.

3. The battery pack according to claim 1 or 2, wherein,

a heat conductor is disposed between adjacent laminated power storage modules in the stacking direction.

4. The battery pack according to claim 1 or 2, wherein,

the space is a cooling gas flow passage.

5. The battery pack according to claim 1,

the space and the battery cell chamber are adjacent only in a direction orthogonal to the stacking direction of the laminated power storage module.

6. The battery pack according to claim 2,

the space and the battery cell chamber are adjacent to each other in both a stacking direction of the laminated power storage module and a direction orthogonal to the stacking direction.