JP2004071178A - Battery assembly - Google Patents

Abstract

Provided is a battery assembly that achieves further compactness and light weight as a combination that can reduce the volume without effectively increasing the number of parts while effectively utilizing the outer shape of a stacked battery.
SOLUTION: The peripheral parts 12b and 13a of a cup-shaped exterior material 12 accommodating a power generation element 11 together with an electrolytic solution in a recess 12a and a planar exterior material 13 covering the recess 12a are joined and sealed, and the power generation element is sealed. Eleven electrode terminals 15 and 16 are drawn out from the sealing portion 14 of the exterior material to form the stacked battery 10. When a plurality of the stacked batteries 10 are combined to form the battery assembly 1 </ b> A, By placing the cup-shaped exterior members 12 of the stacked batteries 10 on the outside and superposing the planar exterior materials 13 on each other, a compact combination can be made without creating a useless space between the stacked batteries 10, and The electrode terminals 15 and 16 are directly connected without using a connecting member.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
In the present invention, a power generating element in which a positive electrode plate and a negative electrode plate are laminated with a separator interposed therebetween is housed together with an electrolytic solution between a cup-shaped exterior material and a planar exterior material, and the peripheral portions of the exterior materials are joined. And a sealed battery assembly.
[0002]
[Prior art]
In recent years, air pollution by automobile exhaust gas has become a global problem, and electric cars powered by electricity and hybrid cars that run with a combination of an engine and a motor have attracted attention and are installed in these. The development of high power type batteries having high energy density and high power density has an important industrial position.
[0003]
Such a high-output battery is, for example, a lithium-ion battery, among which a stacked battery in which a plate-shaped positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween.
[0004]
In this laminated battery, both sides of the flat and rectangular power generating element are sandwiched between a pair of exterior materials formed of a polymer metal composite film such as a laminate sheet, and the periphery thereof is joined by heat fusion. The electrolyte is sealed together with the power generating element.
[0005]
As described above, in a laminated battery using a laminate sheet as an exterior material, it is necessary to increase the width of the sealing portion of the laminate sheet because the leakage of the liquid and the intrusion of moisture are prevented and the reliability of the battery is secured. Therefore, the size of the stacked battery is increased as a whole, and the volume is increased, which may deteriorate the volume energy density of the battery.
[0006]
Therefore, when an assembled battery is constructed using a plurality of the stacked batteries, an attempt has been made to devise the assembled structure according to the outer shape of the battery packaged with the laminate sheet, thereby making the overall volume more compact. ing.
[0007]
That is, as disclosed in Japanese Patent Application Laid-Open No. 2000-200593, the outer shape of the stacked battery is formed in a cup shape in which one outer material has a concave portion for accommodating a power generation element, and the other outer material is formed. Is formed in a planar shape that closes the concave portion, so that the cross section of the concave portion protrudes in a substantially trapezoidal or substantially rectangular shape on one side of the stacked battery, and the other surface is flat on the entire surface. The whole is configured as a substantially flat rectangular shape.
[0008]
And in this case, as a combination structure of the stacked batteries, adjacent stacked batteries are alternately turned upside down and are arranged side by side along the flat surface thereof, and the side surfaces of the protruded concave portions of the adjacent stacked batteries are respectively adjacent to each other. By abutting, the overall length in the juxtaposition direction can be reduced.
[0009]
[Problems to be solved by the invention]
However, in such a conventional battery assembly, adjacent stacked batteries are arranged side by side while being alternately turned upside down. In this case, the side faces of the concave portions of the adjacent stacked batteries are arranged side by side. Even if the length in the direction is shortened, a certain distance is provided in the juxtaposed direction between the adjacent electrode terminals.
[0010]
Therefore, the present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a miniaturized battery assembly by effectively utilizing the outer shape of the stacked battery.
[0011]
[Means for Solving the Problems]
In order to achieve such an object, the battery assembly of the present invention includes a power generation element in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween, and the power generation element is accommodated in a concave portion of the cup-shaped exterior material together with an electrolytic solution. Covering with a planar exterior material, sealing the outer peripheral portions of the cup-shaped exterior material and the planar exterior material by joining them together, and sealing the electrode terminals connected to the positive electrode plate and the negative electrode plate, respectively. A plurality of stacked batteries that are drawn out from the portion are combined to form an assembled battery, and in configuring the assembled battery, a pair of stacked battery of the stacked battery is disposed outside. Then, the flat exterior materials were overlapped with each other to form a battery unit.
[0012]
【The invention's effect】
According to the present invention having such a configuration, when a battery unit is configured by a pair of stacked batteries, the flat outer packaging materials of the stacked batteries are overlapped with each other while the cup-shaped outer packaging materials of the respective stacked batteries are arranged outside. As a result, it is possible to reduce the size and combine the stacked batteries without making useless space between the stacked batteries.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0014]
1 to 5 show a first embodiment of a battery assembly according to the present invention. FIG. 1 is a perspective view of a battery unit, FIG. 2 is a front view of the battery unit, FIG. 4 is an enlarged sectional view taken along line AA in FIG. 3, and FIG. 5 is an exploded perspective view of the battery unit.
[0015]
As shown in FIGS. 1 and 2, the battery assembly of the first embodiment includes a battery unit 1A in which a pair of stacked batteries 10 are combined.
[0016]
As shown in FIGS. 3 and 4, the laminated battery 10 stores a laminated electrode 11 as a power generation element together with an electrolytic solution in a concave portion 12 a of a cup-shaped exterior material 12 formed of a laminate sheet. Is covered with a planar exterior material 13 formed of a laminate sheet, and the peripheral portions 12b and 13a of the cup-shaped exterior material 12 and the planar exterior material 13 are joined and sealed by a method such as heat fusion, and the heat is sealed. The fused portion is a sealing portion 14.
[0017]
As shown in FIG. 4, the laminated electrode 11 is configured by sequentially laminating a plurality of positive plates 11A and negative plates 11B with a separator 11C interposed therebetween, and each positive plate 11A serves as a positive terminal via a positive lead 11D. Each negative electrode plate 11B is connected to a negative electrode tab 16 as a negative electrode terminal via a negative electrode lead 11E.
[0018]
The positive electrode tab 15 and the negative electrode tab 16 are drawn outward from the sealing portion 14 of the cup-shaped outer material 12 and the planar outer material 13. The resin sheet 17 is wrapped around the portion where is disposed in the sealing portion 14 so as to secure the sealing around the two electrode tabs 14 and 15.
[0019]
The stacked battery 10 configured as described above includes, for example, a lithium ion secondary battery. In this case, as a positive electrode active material of a positive electrode forming the positive electrode plate 11A, a lithium nickel composite oxide, specifically, Is a general formula LiNi1-xMxO2 (where 0.01≤x≤0.5, and M is Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca , Sr).
[0020]
The positive electrode can also contain a positive electrode active material other than the lithium nickel composite oxide. As the positive electrode active material other than the lithium nickel composite oxide, for example, a general formula LiyMn2-zM'zO4 (where 0.9≤y≤1.2, 0.01≤z≤0.5, and M 'is Fe , Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, Sr). No.
[0021]
Also, a general formula LiCo1-xMxO2 (where 0.01 ≦ x ≦ 0.5, and M is Fe, Ni, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, At least one of Ca and Sr).
[0022]
Lithium nickel composite oxides, lithium manganese composite oxides, lithium cobalt composite oxides, etc. are prepared by mixing carbonates such as lithium, nickel, manganese, and cobalt in accordance with the composition, and in an oxygen-containing atmosphere at 600 ° C to 1000 ° C. It is obtained by firing in the temperature range of [° C.]. The starting materials are not limited to carbonates, and can be synthesized from hydroxides, oxides, nitrates, organic acid salts, and the like. The average particle size of the positive electrode active material such as a lithium nickel composite oxide and a lithium manganese composite oxide is preferably 30 [μm] or less.
[0023]
On the other hand, as the negative electrode active material forming the negative electrode plate 11B, one having a specific surface area of 0.05 [m ² / g] or more and 2 [m ² / g] or less is used. When the specific surface area of the negative electrode active material is in the range of 0.05 [m ² / g] or more and 2 [m ² / g] or less, formation of the SEI layer on the negative electrode surface can be sufficiently suppressed.
[0024]
When the specific surface area of the negative electrode active material is less than 0.05 [m ² / g], the place where lithium can enter and exit is too small, so that the lithium doped in the negative electrode active material during charging is charged with the negative electrode active during discharging. The material is not sufficiently dedoped from the material, and the charge / discharge efficiency is reduced. On the other hand, when the specific surface area of the negative electrode active material exceeds 2 [m ² / g], formation of the SEI layer on the negative electrode surface cannot be controlled.
[0025]
As a specific negative electrode active material, any material can be used as long as it is capable of doping and undoping lithium with a potential with respect to lithium of 2.0 [V] or less. Firing graphitizable carbon material, artificial graphite, natural graphite, pyrolytic graphite, coke such as pitch coke, needle coke, petroleum coke, graphite, glassy carbon, phenolic resin and furan resin at an appropriate temperature. It is possible to use a carbonaceous material such as a carbonized organic polymer compound fired body, carbon fiber, activated carbon, and carbon black.
[0026]
In addition, a metal capable of forming an alloy with lithium and an alloy thereof can also be used. Specifically, lithium is doped with lithium at a relatively low potential such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, and tin oxide. In addition to an oxide to be dedoped, a nitride thereof, a group 3B typical element, an element such as Si or Sn, or MxSi or MxSn (where M represents one or more metal elements excluding Si or Sn). ) Can be used. Among these, it is particularly preferable to use Si or a Si alloy.
[0027]
Further, the electrolyte used for the electrolyte may be a liquid so-called electrolyte prepared by dissolving an electrolyte salt in a non-aqueous solvent, or a solution in which the electrolyte salt is dissolved in a non-aqueous solvent may be used in a polymer matrix. May be a polymer gel electrolyte held.
[0028]
When a polymer gel electrolyte is used as the non-aqueous electrolyte, the polymer material to be used includes polyvinylidene fluoride, polyacrylonitrile, and the like.
[0029]
As the non-aqueous solvent, any non-aqueous solvent that has been used in this type of non-aqueous electrolyte secondary battery can be used, such as propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, and diethyl carbonate. Dimethyl carbonate, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolan, 4-methyl-1,3-dioxolan, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile and the like. One of these non-aqueous solvents may be used alone, or two or more of them may be used in combination.
[0030]
In particular, the non-aqueous solvent preferably contains an unsaturated carbonate, and specifically, preferably contains vinylene carbonate, ethyleneethylidene carbonate, ethyleneisopropylidene carbonate, propylidene carbonate, and the like. Among them, it is most preferable to contain vinylene carbonate. By containing unsaturated carbonate as the non-aqueous solvent, it is considered that an effect due to the properties of the SEI layer generated in the negative electrode active material is obtained, and the overdischarge resistance is further improved.
[0031]
Further, the unsaturated carbonate is preferably contained in the electrolyte at a ratio of 0.05% by weight or more and 5% by weight or less, and more preferably at a ratio of 0.5% by weight or more and 3% by weight or less. Most preferred. By setting the content of the unsaturated carbonate in the above range, a non-aqueous secondary battery having a high initial discharge capacity and a high energy density can be obtained.
[0032]
The electrolyte salt is not particularly limited as long as it is a lithium salt having ion conductivity. For example, LiClO4, LiAsF6, LiPF6, LiBF4, LiB (C6H5) 4, LiCl, LiBr, CH3SO3Li, CF3SO3Li, etc. can be used. is there. One of these electrolyte salts may be used alone, or two or more thereof may be used in combination.
[0033]
The stacked battery 10 thus configured has a concave portion 12a protruding in a trapezoidal cross section on one side (upper side in FIG. 4) covered with the cup-shaped exterior material 12 and another side covered with a planar exterior material 13 (see FIG. 4). 4 is formed flat on the entire surface.
[0034]
Therefore, in the first embodiment, as shown in FIG. 5, the battery unit 1A is arranged such that the cup-shaped exterior members 12 of the pair of stacked batteries 10 are arranged outside, and the respective planar exterior members 13 are opposed to each other. In this way, the flat exterior material 13 as shown in FIGS. 1 and 2 is overlapped.
[0035]
In addition, in the battery unit 1 </ b> A configured by stacking the stacked batteries 10 with the planar exterior material 13 as described above, the positive electrode tabs 15 and the negative electrode tabs 16 as illustrated in FIG. The pair of positive and negative electrode tabs 15 and 16 are connected to each other by a method such as welding (indicated by a mark x in the drawing) or the like, and the battery unit 1A is formed in a pair. The battery cells 10 are connected in parallel.
[0036]
The positive electrode tab 15 is formed of an aluminum (Al) foil having a thickness of approximately 100 [μm], and the negative electrode tab 16 is formed of a nickel (Ni) foil having a thickness of approximately 100 [μm]. As a means, a technique such as an ultrasonic welding method is used.
[0037]
The battery unit 1A is integrated by bonding the stacked batteries 10 together via an adhesive applied to the peripheral portion 13a of the stacked planar exterior material 13 as indicated by a portion K in FIG. Is becoming
[0038]
That is, by bonding only at the peripheral portion 13a of the stacked battery 10 in this manner, a portion corresponding to the concave portion 12a in which the stacked electrode 11 is stored is prevented from being bonded.
[0039]
As the adhesive used for bonding the peripheral portion 13a, a double-sided tape, a non-curable adhesive, an adhesive having no conductive function, or the like is selected.
[0040]
Further, in order to join the stacked batteries 10 of the battery unit 1A, the positive electrode tabs 15 and the negative electrode tabs 16 are welded as described above without using the adhesive (K portion) (FIG. 3). (Indicated by M in the figure)).
[0041]
With the above configuration, in the battery assembly according to the first embodiment, the pair of stacked batteries 10 constituting the battery unit 1A are placed on the respective flat surfaces while the respective cup-shaped exterior members 12 are arranged outside. Since the outer package members 13 are superimposed on each other, it is possible to reduce the size of the stacked batteries 10 without creating a useless space between the stacked batteries 10 and combine them, and to reduce the volume of the stacked batteries 10.
[0042]
In addition, since the pair of stacked batteries 10 have the planar exterior material 13 overlapped thereon, the positive electrode of each of the stacked batteries 10 drawn outward from the sealing portion 14 of the cup-shaped exterior material 12 and the planar exterior material 13 Since the tabs 15 and the negative electrode tabs 16 are opposed to each other with only the thickness of each of the planar exterior members 13 therebetween, the positive electrode tabs 15 and the negative electrode tabs 16 of each stacked battery 10 can be arranged close to each other. .
[0043]
Therefore, the positive electrode tabs 15 and the negative electrode tabs 16 can be directly connected to each other without using another connecting member such as a bus bar, thereby preventing an increase in the number of parts, and The weight of the battery unit 1A can be reduced.
[0044]
Further, in the battery unit 1A of the first embodiment, since the stacked stacked batteries 10 are integrated by bonding the peripheral portion 13a of the planar exterior material 13, it corresponds to the concave portion 12a in which the stacked electrode 11 is stored. The central part can be prevented from being glued. Therefore, when a pressing force is applied from the outside to between the concave portions 12a of the pair of stacked batteries 10, the pressing force can be uniformly applied to the stacked electrodes 11 of both stacked batteries 10.
[0045]
That is, as described above, the laminated electrode 11 is formed by laminating a plurality of positive plates 11A and a plurality of negative plates 11B with the separator 11C interposed therebetween. It is known that the distance between the negative electrode plates 11A and 11B is constant and the battery performance can be improved. Therefore, even in this embodiment, by avoiding the central portion of the planar exterior material 13 from being adhered, an appropriate surface pressure can be uniformly applied to the laminated electrodes 11 of the two laminated batteries 10 by the pressing force. Therefore, battery performance can be improved.
[0046]
Furthermore, when the pair of stacked batteries 10 of the battery unit 1A are overlapped and integrated, a welded portion M in which the respective positive electrode tabs 15 and the respective negative electrode tabs 16 are joined may be used. In this case, Since the work of bonding the planar exterior members 13 to each other can be omitted, the assembly process of the battery unit 1A can be simplified.
[0047]
FIGS. 6 and 7 show a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.
[0048]
FIG. 6 is a front view showing a battery unit laminate, and FIG. 7 is a front view showing a process of forming the battery unit laminate. The battery assembly according to the second embodiment is the same as the battery assembly according to the first embodiment. A plurality of (in the present embodiment, four) units 1A are stacked in the vertical direction of the planar exterior material 13 to constitute a sub-module pack 1B.
[0049]
That is, as shown in the first embodiment, the stacked batteries 10 constituting each battery unit 1A of the sub-module pack 1B are connected in parallel by welding the respective positive electrode tabs 15 and the respective negative electrode tabs 16 together. Accordingly, each battery unit 1A can be regarded as one battery.
[0050]
At this time, the positive electrode tabs 15 and the negative electrode tabs 16 connected in parallel function as a positive electrode terminal 15A and a negative electrode terminal 16A of each battery unit 1A.
[0051]
Then, when configuring the sub-module pack 1B, the positive electrode terminals 15A and the negative electrode terminals 16A are alternately arranged in the adjacent battery units 1A as shown in FIG. The battery units 1A are arranged in a bellows shape by alternately approaching the positive terminals 15A and the negative terminals 16A so that they are connected in series.
[0052]
Then, the positive electrode terminal 15A and the negative electrode terminal 16A of the adjacent battery unit 1A are joined by welding M1 (in this case, ultrasonic welding) with a margin s for the thickness t of the stacked battery 10.
[0053]
In addition, after the battery units 1A are arranged in a bellows shape and the positive terminal 15A and the negative terminal 16A are connected in series, the battery units 1A arranged in a bellows are folded close to each other as shown in FIG. The battery units 1A can be stacked to form the sub-module pack 1B.
[0054]
Therefore, in the battery assembly of the second embodiment, four sub-module packs 1B are formed by laminating four battery units 1A in the vertical direction of the planar exterior material 13, so that the sub-module pack 1B When one stack type battery 10 is used as a unit, a two-parallel × 4 series structure is obtained.
[0055]
Further, as shown in the first embodiment, the sub-module pack 1B is formed by using a plurality of compact and lightweight battery units 1A and stacking them in series in the stacking direction of the stacked battery 10. In addition, the overall volume can be reduced while configuring a battery assembly that can handle a large current.
[0056]
Furthermore, when the positive terminal 15A and the negative terminal 16A are connected between the adjacent battery units 1A, the sub-module pack 1B adds the thickness t of the stacked battery 10 to each of the positive terminal 15A and the negative terminal 16A. Since each battery unit 1A is stacked with the positive electrode terminal 15A and the negative electrode terminal 16A connected, the bending margin of the positive electrode terminal 15A and the negative electrode terminal 16A is reduced, and the positive electrode terminal 15A and the negative electrode terminal 16A are reduced. Since bending stress acting on the negative electrode terminal 16A can be suppressed as much as possible, breakage and breakage of the positive electrode terminal 15A and the negative electrode terminal 16A can be prevented.
[0057]
FIG. 8 shows a third embodiment of the present invention, in which the same components as those in the first and second embodiments are denoted by the same reference numerals, and redundant description will be omitted.
[0058]
FIG. 8 is a cross-sectional view of a main part of a battery module 1 using a stacked body of battery units 1A. The battery assembly of the third embodiment uses the sub-module pack 1B shown in the second embodiment as a basic unit. The sub-module pack 1B is arranged in a pressurized state between a pair of bus bar plates 21 arranged at a predetermined interval L in the case 20, and the positive and negative collective electrodes 15B and 16B of the sub-module pack 1B are placed on both sides. The battery module 1 is configured by being connected to the bus bar plate 21 of FIG.
[0059]
In other words, by arranging the sub-module pack 1B between the bus bar plates 21 in a sandwiching state, the sub-module pack 1B is pressed in the stacking direction to apply a surface pressure to the stacked electrodes 11 of each stacked battery 10. Has become.
[0060]
Further, the current of the submodule pack 1B taken out to each bus bar plate 21 is taken out of the case 20 with a series or parallel connection structure.
[0061]
Further, each busbar plate 21 is formed of a metal plate having a high thermal conductivity such as an aluminum plate, and a part thereof is formed as a cooling unit by protruding outside of the case 20 so that a function of a heat sink is provided. It is made to double.
[0062]
Therefore, in the battery module 1 of the third embodiment, the sub-module pack 1B having the two-parallel × 4 series structure shown in the second embodiment is housed in the case 20, and is configured. Since the submodule pack 1B is compact and lightweight, the size and weight of the battery module 1 can be reduced.
[0063]
Further, since the sub-module pack 1B is arranged between the bus bar plates 21 in a state of being pressed, the surface performance can be applied to each of the stacked batteries 10 to improve the battery performance.
[0064]
Further, since the bus bar plate 21 also functions as a heat sink, the heat generated in the sub-module pack 1B is released to the outside, so that the heat is not hidden in the case 20 and the excessive heat generation of the stacked battery 10 is prevented. As a result, the battery performance can be prevented from deteriorating.
[0065]
By the way, the battery assembly of the present invention has been described by taking the first to third embodiments as examples, but various embodiments can be adopted without departing from the gist of the present invention without being limited thereto. For example, a lithium ion secondary battery is shown as a stacked battery, but the present invention is not limited to this, and the present invention can be applied to other batteries having the same configuration. Also in the case where the combination of the pair of stacked batteries 10 has a basic structure, the submodule pack 1B shows a case where four battery units 1A are stacked, but it is needless to say that the number of batteries is not limited to four and two or more. Units 1A can be combined to form a basic set unit.
[Brief description of the drawings]
FIG. 1 is a perspective view of a battery unit according to a first embodiment of the present invention.
FIG. 2 is a front view of the battery unit according to the first embodiment of the present invention.
FIG. 3 is a plan view of the stacked battery according to the first embodiment of the present invention.
FIG. 4 is an enlarged sectional view taken along line AA in FIG.
FIG. 5 is an exploded perspective view of the battery unit according to the first embodiment of the present invention.
FIG. 6 is a front view showing a stacked body of a battery unit according to a second embodiment of the present invention.
FIG. 7 is a front view illustrating a process of forming a battery unit laminate according to a second embodiment of the present invention.
FIG. 8 is a sectional view of a main part of a battery module using a battery unit laminate according to a third embodiment of the present invention.
[Explanation of symbols]
1 Battery module (battery assembly)
1A Battery unit (battery assembly)
1B sub-module pack (battery assembly)
10 Stacked battery 11 Stacked electrode (power generation element)
12 cup-shaped exterior material 12a concave portion 12b peripheral edge 13 flat exterior material 13a peripheral edge 14 sealing portion 15 positive electrode tab (electrode terminal)
15A Positive electrode terminal (electrode terminal)
15B Collective electrode 16 Negative electrode tab (electrode terminal)
16A Negative electrode terminal (electrode terminal)
16B Collective electrode 20 Case 21 Busbar plate

Claims (7)

A power generating element in which a positive electrode plate and a negative electrode plate are laminated with a separator interposed therebetween is housed together with an electrolytic solution in a recess of the cup-shaped exterior material, and the recess is covered with a planar exterior material. A laminated battery in which the peripheral edges of the exterior material are joined and sealed, and the electrode terminals connected to the positive electrode plate and the negative electrode plate, respectively, are drawn outward from the sealed portion of the sealed exterior material. In a battery assembly configured by combining a plurality of the stacked batteries,
A battery assembly comprising: a pair of the above-mentioned stacked batteries, wherein the above-mentioned planar exterior materials are overlapped with each other while the above-mentioned cup-shaped exterior materials are arranged outside, to form a battery unit. 2. The battery assembly according to claim 1, wherein a plurality of the battery units are stacked in a direction perpendicular to the planar exterior material. 3. 3. The battery assembly according to claim 1, wherein the battery unit is configured such that the stacked stacked batteries are joined together at a peripheral portion of the exterior material to be integrated. 4. 3. The battery assembly according to claim 1, wherein the battery unit is formed by joining the stacked batteries at their respective electrode terminals and integrating them. 4. In the battery unit in which a plurality of battery units are stacked, the electrode terminals of the stacked batteries constituting each of the battery units are joined together, and the joined electrode terminals are provided with a margin for the thickness of the stacked battery between adjacent battery units. The battery assembly according to claim 2, wherein the battery assembly is joined with a margin. A predetermined number of the battery units are stacked in the vertical direction of the planar exterior material to form a basic group unit, and a battery unit group of the basic group unit is sandwiched between a pair of busbar plates arranged at predetermined intervals in a case. The battery assembly according to any one of claims 1 to 5, wherein the battery assemblies are arranged in a state, and the collective electrodes of the battery unit group are connected to bus bar plates on both sides. The battery assembly according to claim 6, wherein the bus bar plate also serves as a heat sink.

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