JP4039197B2 - Laminated battery, module having a plurality of laminated batteries connected thereto, assembled battery having a plurality of connected modules, and vehicle equipped with the assembled battery - Google Patents

Description

【００５５】
上記結果に示すように、密閉部材なしの場合では、融着幅２０ｍｍの方が融着幅１０ｍｍに比較して液漏れ数が少ないものの、５％も液漏れが発生している。これに対し、密閉部材ありの場合では、該密閉部材に耐腐食性があってもなくても、液漏れ発生率はほぼ０パーセントである。
【００５６】
この結果からもわかるように、ラミネート電池に本発明の密閉部材を適用すれば、ラミネート電池の液漏れをかなり低減でき、結果として、ラミネート電池の寿命を延長することができる。
【図面の簡単な説明】
【図１】 本発明のラミネート電池の平面図である。
【図２】 本発明のラミネート電池をタブの伸延方向と直角な方向から見た側面図である。
【図３】 本発明のラミネート電池をタブ方向の伸延方向から見た側面図である。
【図４】 図１に示すラミネート電池のＡ−Ａ断面図である。
【図５】 本発明のモジュールの一例を示す図である。
【図６】 本発明の組電池の一例を示す図である。
【図７】 本発明の組電池を搭載する自動車の斜視図である。
【符号の説明】
１…ラミネート電池、２…電池要素、３…ラミネートシート、４…タブ、５…結合部材、６…絶縁部材、７…密閉部材、８…モジュール、１０…組電池、１２…自動車、３１…熱融着性樹脂フィルム、３２…金属箔、３３…樹脂フィルム。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated battery, a module in which a plurality of the laminated batteries are connected, an assembled battery in which a plurality of the modules are connected, and a vehicle equipped with the assembled battery.
[0002]
[Prior art]
2. Description of the Related Art In recent years, motor drive batteries have been developed with the aim of putting electric vehicles (EV), hybrid vehicles (HEV), and fuel cell vehicles (FCV) into practical use. As a battery for driving a motor, the use of a secondary battery that can be repeatedly charged has been proposed.
[0003]
Examples of the secondary battery proposed so far include a can battery having a structure in which battery elements are arranged inside a metal can, and a laminate having a structure in which battery elements are sealed using a laminate sheet. There are batteries. As a power source for a mobile body such as an automobile, a laminated battery that is useful for reducing weight and size is preferable.
[0004]
By the way, when moisture in the air penetrates into the secondary battery, deterioration of battery characteristics is caused by a chemical reaction. Therefore, the battery element of the secondary battery needs to be completely sealed so as not to come into contact with outside air. In particular, since a laminated battery is inferior in sealing property to a can battery, development of a means for ensuring the sealing property of the laminated battery is desired.
[0005]
As a technique for dealing with this problem, for example, there has been made in consideration of the fact that the sealing property of the exterior structure made of a laminate sheet is lowered in the sealing portion into which the electrolyte is injected, and moisture in the outside air is likely to enter ( For example, see Patent Document 1.) In the present invention, the sealing portion is further covered with a sealing portion auxiliary member for ensuring the sealing performance of the sealing portion.
[0006]
If it is applied to a relatively short-term application (for example, a mobile phone normally used for 2 to 3 years), it may be sufficient if the exterior structure has a certain degree of sealing performance. However, if it is applied to a relatively long-term application (for example, an automobile that is usually used for several years, sometimes 10 years or more), it is desirable that the exterior structure has a higher sealing performance. Is done. In particular, when used as a power source for automobiles, since the laminated battery is exposed to vibration and heat, high sealing performance is desired.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-223087
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an exterior structure that maintains hermeticity over a long period of time, thereby maintaining the battery characteristics of the laminated battery over a long period of time.
[0009]
[Means for Solving the Problems]
The present invention provides a battery element having a laminated structure, a laminate sheet for sealing the battery element inside, and the battery element to the outside of the laminate sheet so that the battery element can be electrically connected to the outside. and tabs drawn in, the tub is provided so as to cover a part of the end portion and the tabs of the laminate sheet drawn, have a, a sealing member for sealing said laminate sheet, wherein the sealing member is It is a laminate battery formed by depositing metal on the end of the laminate sheet and a part of the tab by vapor deposition or sputter deposition .
[0010]
【The invention's effect】
The laminate battery of the present invention having the above-described configuration maintains its sealing property for a long period of time, and can prevent moisture in the atmosphere from penetrating into the laminate battery, thereby maintaining the battery characteristics for a long period of time. can do.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
FIG. 1 is a plan view of a laminated battery of the present invention, FIG. 2 is a side view of the laminated battery of the present invention viewed from a direction perpendicular to the extending direction of the tab, and FIG. 3 is a side view of the laminated battery of the present invention viewed from the extending direction in the tab direction. FIG. 4 is a side view of the laminated battery shown in FIG.
[0013]
The first of the present invention is a laminated battery 1. As shown in FIGS. 1 to 4, a laminated battery 1 of the present invention includes a battery element 2 having a laminated structure, a laminate sheet 3 that seals the battery element 2 inside, and the battery element 2 to the outside of the laminate sheet 3. In order to couple the tab 4 drawn out to the laminate sheet 3 and the tab 4, a coupling member 5 disposed between the laminate sheet 3 and the tab 4 and an end surface of the laminate sheet 3 are provided. The sealing member 7 is provided so as to cover the insulating member 6, the end of the laminate sheet 3 from which the tab 4 is drawn, a part of the coupling member 5, the insulating member 6 and a part of the tab 4. And have.
[0014]
The battery element 2 is formed by laminating a positive electrode, a separator, a negative electrode, and the like that are substantially involved in charge / discharge.
[0015]
The laminate sheet 3 is used as an exterior material of the laminate battery 1 and is a set of two sheets. At least one laminate sheet 3 is formed in a medium-high shape so that when two laminate sheets 3 are put together, a space for enclosing the battery element 2 is formed between them.
[0016]
As shown in FIG. 4, the laminate sheet 3 is generally a polymer metal composite film in which a heat-fusible resin film 31, a metal foil 32, and a rigid resin film 33 are laminated in this order. .
[0017]
The tab 4 is made of metal, and is drawn from the battery element 2 to the outside of the laminate sheet 3 and extends so that the battery element 2 can be electrically connected to the outside.
[0018]
The coupling member 5 is disposed between the laminate sheet 3 and the tab 4 and couples them with adhesiveness by heat fusion. Here, the coupling member 5 surrounds the periphery of the tab 4 so that the tab 4 and the laminate sheet 3 do not directly contact each other. The range in which the coupling member 5 surrounds the periphery of the tab 4 is not particularly limited as long as the tab 4 and the laminate sheet 3 can be brought into contact with each other.
[0019]
The insulating member 6 is made of an insulator, for example, polypropylene, and is in contact with the end surface of the side from which the tab 4 of the laminate sheet 3 is drawn, and is fused to the end surface.
[0020]
The sealing member 7 is formed so as to cover the laminate sheet 3, the insulating member 6, the coupling member 5, and the tab 4 along the side from which the tab 4 of the laminate sheet 3 is drawn. As a method for forming the sealing member 7, vapor deposition or sputter deposition is used. Therefore, the sealing member 7 is formed of a metal that can be vapor-deposited or sputtered.
[0021]
When performing the vapor deposition process or the sputter adhesion process, first, as shown in FIGS. 1 to 4, a mask is applied to a part other than the part where the tab 4 of the laminate sheet 3 is drawn out, except for the part where the sealing member 7 is to be formed. Turn on. Then, by performing vapor deposition processing or sputter deposition processing, the metal is deposited on the entire surface including the mask, and then the mask is removed, thereby leaving the metal only at a desired portion and forming the sealing member 7. .
[0022]
As described above, in the present invention, the sealing member 7 is formed along the side of the laminate sheet 3 from which the tab 4 protrudes. Therefore, the sealing member 7 makes the sealing property between the laminate sheet 3 and the tab 4 stronger, and maintains this sealing property for a long period of time, whereby the battery characteristics of the laminated battery 1 are maintained for a long period of time. Can be sustained.
[0023]
Further, in the laminated battery 1, since the coupling member 5 is disposed between the laminate sheet 3 and the tab 4 and bonded by thermal welding, the coupling member 5 tightly couples the laminate sheet 3 and the tab 4, The sealing property between the laminate sheet 3 and the tab 4 can be improved.
[0024]
Further, in the laminate battery 1, the insulating member 6 is in contact with and fused to the end face of the side from which the tab 4 of the laminate sheet 3 is drawn. Therefore, the sealing member 7 formed in contact with the tab 4 does not come into contact with the metal film 32 constituting the laminate sheet 3. Thereby, it is possible to prevent the laminated battery 1 from being short-circuited due to the tab 4 being connected to the tab 4 extending to the other side of the battery element 2 by the conductor.
[0025]
Next, materials for forming the constituent elements of the laminated battery 1 will be described, and effects obtained by applying the materials will be described.
[0026]
(Sealing member)
As described above, the sealing member 7 which is a feature of the present invention is formed on the laminated battery 1 by vapor deposition or sputtering adhesion. Therefore, naturally, the metal suitable for these processes is used for the material. Examples of such metals include aluminum, gold, platinum, copper, and alloys thereof. By forming the metal sealing member 7 on the laminate battery 1, it is possible to prevent moisture in the outside air from entering the laminate battery 1 between the laminate sheet 3 and the tab 4. Deterioration of the battery 1 can be prevented. Further, since the inside of the laminate battery 1 is sealed, leakage of the electrolyte solution enclosed in the laminate battery 1 can be prevented.
[0027]
In particular, as the material of the sealing member 7, it is desirable to use a metal having corrosion resistance such as platinum, copper, or an alloy thereof. By using a metal having corrosion resistance, corrosion deterioration due to oxidation of the sealing member 7 can be prevented, and the battery durability of the laminated battery 1 can be improved. As a result, the battery life can be extended. .
[0028]
Moreover, since the sealing member 7 is formed of metal, it has excellent heat dissipation and strength. Therefore, the heat generation of the laminated battery 1 can be promoted as compared with the case where the sealing member 7 is not provided, and thereby, the performance deterioration due to the deterioration of the laminated battery 1 can be prevented. Furthermore, since the sealing member 7 covers both ends of the laminate sheet 3, the strength of the laminate battery 1 can be improved.
[0029]
(Coupling member)
The coupling member 5 needs to ensure the sealing performance between the laminate sheet 3 and the tab 4 and suppress the penetration of moisture into the laminate battery 1. Accordingly, it is conceivable to use, for example, a material that has a very slow moisture permeation rate or a material that can adsorb and remove moisture.
[0030]
Specifically, it is preferable to use a thermoplastic resin containing a moisture absorbent as the material constituting the coupling member 5. By including the moisture absorbent, the moisture that has permeated is removed, so that the moisture can be prevented from reaching the inside of the laminated battery 1. Examples of the thermoplastic resin include known materials such as polyethylene, polypropylene, polystyrene, AS resin (acrylonitrile / styrene copolymer resin), ABS resin (acrylonitrile / butadiene / styrene copolymer resin), polyvinyl chloride, methacrylic resin, polyethylene. Examples include terephthalate. Examples of the water absorbent include known water absorbents such as silica gel, activated carbon, and zeolite.
[0031]
Preferably, the coupling member 5 is made of polyethylene. In this case, the moisture absorbent described above may or may not be included. Polyethylene is effective in suppressing the penetration of moisture because the penetration rate of moisture is slow among thermoplastic resins. Further, it is widely used as a general-purpose polymer material and is easily available. In addition, when not using a water | moisture-content absorber, it is also possible to hold down manufacturing cost.
[0032]
In the laminated battery 1 of the present invention, the bonding member 5 is disposed between the laminate sheet 3 and the tab 4 in order to more effectively prevent moisture from penetrating into the laminated battery 1. There is no problem even if is not arranged. In the present invention, since the metal sealing member 7 is attached along the side of the laminate sheet 3 from which the tab 4 is drawn, it is possible to sufficiently prevent the penetration of moisture into the laminate battery 1. .
[0033]
In the above, the material of the sealing member 7 and the coupling member 5 which are the characteristics of this invention was demonstrated. Next, materials such as the battery element 2 having a laminated structure, the laminate sheet 3, and the tab 4 in the laminate battery 1 of the present invention will be described for reference, and a known material may be used for these, in particular. It is not limited.
[0034]
Hereinafter, the case where the laminate battery of the present invention is a lithium ion secondary battery will be briefly described. However, the laminate battery of the present invention is not limited to the lithium ion secondary battery. Examples of the laminate battery of the present invention include a polymer lithium battery, a nickel-hydrogen battery, and a nickel-cadmium battery. Of these, lithium ion secondary batteries excellent in output and energy density are preferable in consideration of applications as power sources for vehicles.
[0035]
[Positive electrode]
The positive electrode has a structure in which a positive electrode material is bound on both surfaces of a positive electrode current collector made of aluminum or the like. As the positive electrode material, various oxides (lithium manganese oxide such as LiMn ₂ O ₄ ; manganese dioxide; lithium nickel oxide such as LiNiO ₂ ; lithium cobalt oxide such as LiCoO ₂ ; lithium-containing nickel cobalt oxide; lithium And amorphous vanadium pentoxide containing), chalcogen compounds (titanium disulfide, molybdenum disulfide, etc.), and the like. Among these, lithium manganese oxide or lithium nickel oxide is preferable in consideration of output characteristics of the obtained lithium ion secondary battery.
[0036]
In order to improve conductivity, the positive electrode current collector may be bound together with a conductive material. Examples of the conductive material include artificial graphite, carbon black (for example, acetylene black), nickel powder, and the like.
[0037]
As the positive electrode current collector, for example, an aluminum expanded metal, an aluminum mesh, an aluminum punched metal, or the like can be used. Note that the positive electrode may have a structure in which a positive electrode material is bound to one surface of a positive electrode current collector.
[0038]
[Negative electrode]
The negative electrode has a structure in which a negative electrode material is bound to both surfaces of a negative electrode current collector made of copper or the like. As the negative electrode material, a carbon material that occludes and releases lithium ions can be used. As such carbon materials, natural graphite, artificial graphite, carbon black, activated carbon, carbon fiber, coke, organic precursors (for example, phenol resin, polyacrylonitrile, cellulose, etc.) were synthesized by heat treatment in an inert atmosphere. Examples include carbon. Preferably, the negative electrode is made of an amorphous carbon-based material. In the present application, “amorphous carbon-based material” means a carbon material having no crystal structure, in other words, an amorphous carbon material. Such an amorphous carbon material can be obtained by carbonizing a thermosetting resin. Incidentally, when an amorphous carbon material having a large voltage dependency due to discharge is used, the cycle characteristics of the lithium ion secondary battery when two or more lithium ion secondary batteries are connected in parallel can be improved.
[0039]
As the negative electrode current collector, for example, copper expanded metal, copper mesh, copper punched metal, or the like can be used. Note that the negative electrode may have a structure in which a negative electrode material is bound to one surface of a negative electrode current collector.
[0040]
[Separator]
As the separator, a polyolefin-based microporous separator such as polyethylene or polypropylene can be used, and the separator is impregnated with a non-aqueous electrolyte. The nonaqueous electrolytic solution is prepared by dissolving an electrolyte in a nonaqueous solvent. Nonaqueous solvents include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (γ-BL ), Sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran and the like. Nonaqueous solvents may be used alone or in combination of two or more. Examples of the electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium boron tetrafluoride (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), and lithium trifluoromethanesulfonate. Examples include lithium salts such as (LiCF ₃ SO ₃ ) and bistrifluoromethylsulfonylimide lithium [LiN (CF ₃ SO ₃ ) ₂ ]. The amount of the electrolyte dissolved in the non-aqueous solvent is usually about 0.2 mol / L to 2 mol / L.
[0041]
Examples of the polymer that holds the nonaqueous electrolytic solution include a polyethylene oxide derivative, a polypropylene oxide derivative, a polymer containing the derivative, a copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP), and the like.
[0042]
[Laminate sheet]
The laminate sheet is used as a battery exterior material. In general, a polymer metal composite film in which a heat-fusible resin film, a metal foil, and a resin film having rigidity are laminated in this order is used.
[0043]
As the heat-fusible resin, for example, polyethylene (PE), ionomer, ethylene vinyl acetate (EVA) or the like can be used. As the metal foil, for example, Al foil or Ni foil can be used. As the resin having rigidity, for example, polyethylene terephthalate (PET), nylon or the like can be used. Specifically, PE / Al foil / PET laminated film laminated from the sealing surface side to the outer surface; PE / Al foil / nylon laminated film; Ionomer / Ni foil / PET laminated film; EVA / Al foil / A laminated film of PET; an ionomer / Al foil / PET laminated film or the like can be used. The heat-fusible resin film acts as a seal layer when the battery element is housed inside. A metal foil or a rigid resin film imparts moisture, breathability, and chemical resistance to the exterior material. The laminate sheet can be easily and reliably bonded using ultrasonic fusion or the like.
[0044]
[tab]
A metal selected from copper and iron can be used for the tab, but a metal such as aluminum or stainless steel or an alloy material containing these metals can also be used. Further, nickel can be most preferably used for the surface coating layer, but metal materials such as silver and gold can be used as well.
[0045]
The laminate battery of the present invention can be produced using a known technique that would be conceived by those skilled in the art. For example, the sheet member is arranged at a predetermined position of the tab by using a heat fusion technique. Connect this tab to the battery element. Next, the battery element to which the tab is connected is wrapped with a laminate sheet, and heat-sealed, leaving a sealing portion for injecting the electrolyte. At this time, the tab is pulled out to the outside of the laminate sheet and heat-sealed at a predetermined position. Then, electrolyte solution is inject | poured through a sealing part, a sealing part is closed by heat sealing, and a laminated battery is completed. However, of course, it is not limited to this manufacturing method.
[0046]
The second of the present invention is a module formed by connecting a plurality of the laminated batteries 1 in series and / or in parallel. For reference, FIG. 5 shows an example of the module 8 of the present invention. FIG. 5 is a diagram showing an example of the module 8 of the present invention.
[0047]
For example, as shown in FIG. 5, the module 8 is formed by arranging and connecting four laminated batteries 1 on a substrate 9 in parallel. Naturally, the number and connection of the laminated batteries 1 to be juxtaposed to the module may be determined according to the desired electrical characteristics, and the module of the present invention is not limited to that shown in FIG.
[0048]
A third aspect of the present invention is an assembled battery formed by connecting a plurality of the above modules in series and / or in parallel. For reference, an example of the assembled battery 10 of the present invention is shown in FIG. FIG. 6 is a diagram illustrating an example of the assembled battery 10 of the present invention.
[0049]
For example, as shown in FIG. 6, the assembled battery 10 is formed by laminating modules 8 using a tape 11 without a gap. Lamination without gaps is preferable from the viewpoint of volume energy density of the assembled battery. However, when laminated without gaps, the heat dissipation of the laminated battery 1 included in the module 8 may deteriorate. Therefore, it is possible to stack the modules 8 with a gap and improve the heat dissipation. Thus, the connection method of the module 8 is not limited to that shown in FIG. 6, and can be changed as appropriate based on the environment, configuration, etc. in which the assembled battery 10 is used.
[0050]
A fourth aspect of the present invention is a vehicle on which the assembled battery 10 is mounted. For reference, FIG. 7 shows a perspective view of an automobile 12 on which the assembled battery 10 of the present invention is mounted. FIG. 7 is a perspective view of the automobile 12 on which the assembled battery 10 of the present invention is mounted. The assembled battery 10 mounted on the vehicle has the characteristics of the laminate battery 1. For this reason, the automobile 12 on which the assembled battery 10 of the present invention is mounted has high durability, and can provide a sufficient output even after being used for a long period of time.
[0051]
The effects of the present invention will be described in more detail using the following examples. However, it goes without saying that the technical idea of the present invention is not limited to the following examples.
[0052]
<Example>
In this embodiment, the laminated battery has a fusion width between the laminate sheet 3 and the tab 4 of 10 mm or 20 mm, and (1) does not have the sealing member 7 of the present invention, and (2) the sealing member of the present invention. 7 was prepared, and the sealing member 7 was not a corrosion-resistant metal, and (3) the sealing member 7 of the present invention was provided, and the sealing member 7 was a corrosion-resistant metal. And it was left to stand for six months, and after that, it was investigated how many of the electrolytes of the laminate battery out of 100 sheets leaked to the outside. Whether or not the liquid was leaking was judged by contacting the pH test paper between the laminate sheet and the tab and showing the alkalinity of the electrolyte.
[0053]
The experimental results are as shown in the following table.
[0054]
[Table 1]

[0055]
As shown in the above results, in the case where there is no sealing member, although the number of liquid leaks is smaller when the fusion width is 20 mm than when the fusion width is 10 mm, liquid leakage occurs as much as 5%. On the other hand, in the case where there is a sealing member, the occurrence rate of liquid leakage is almost 0% regardless of whether or not the sealing member has corrosion resistance.
[0056]
As can be seen from this result, when the sealing member of the present invention is applied to a laminated battery, the liquid leakage of the laminated battery can be considerably reduced, and as a result, the life of the laminated battery can be extended.
[Brief description of the drawings]
FIG. 1 is a plan view of a laminated battery of the present invention.
FIG. 2 is a side view of the laminated battery of the present invention viewed from a direction perpendicular to the extending direction of the tab.
FIG. 3 is a side view of the laminated battery of the present invention as viewed from the extending direction in the tab direction.
4 is a cross-sectional view taken along line AA of the laminated battery shown in FIG.
FIG. 5 is a diagram showing an example of a module of the present invention.
FIG. 6 is a diagram showing an example of an assembled battery according to the present invention.
FIG. 7 is a perspective view of an automobile equipped with the assembled battery of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Laminated battery, 2 ... Battery element, 3 ... Laminate sheet, 4 ... Tab, 5 ... Coupling member, 6 ... Insulating member, 7 ... Sealing member, 8 ... Module, 10 ... Assembly battery, 12 ... Car, 31 ... Heat Fusible resin film, 32 ... metal foil, 33 ... resin film.

Claims (6)

A battery element having a laminated structure;
A laminate sheet for sealing the battery element therein;
A tab that is drawn from the battery element to the outside of the laminate sheet so that the battery element can be electrically connected to the outside;
A sealing member provided so as to cover an end of the laminate sheet from which the tab is pulled out and a part of the tab, and seals the inside of the laminate sheet;
I have a,
The sealing member is a laminate battery formed by attaching metal to the end portion of the laminate sheet and a part of the tab by vapor deposition or sputter deposition . The laminate battery according to claim 1 , further comprising a coupling member disposed between the laminate sheet and the tab in order to couple the laminate sheet and the tab . The laminate battery according to claim 1, wherein the sealing member is formed of aluminum, gold, platinum, copper, or an alloy thereof . A module formed by connecting a plurality of the laminated batteries according to claim 1. An assembled battery formed by connecting a plurality of modules according to claim 4. A vehicle comprising the assembled battery according to claim 5.

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