JP3711962B2 - Thin battery - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a thin battery having a terminal led out from an edge of an outer peripheral portion of a sealing means, and more particularly to a thin battery having a structure strong against an applied external force.
[0002]
[Background]
With the diversification of usage modes and usage conditions of thin batteries having terminals led out from the edge of the outer peripheral portion of the sealing means, external forces such as vibrations applied from the outside to the thin batteries increase. Due to this external force, the terminal of the thin battery terminal is led out from the battery outer member (hereinafter also referred to as a terminal lead-out portion) or the sealing portion of the battery outer member is pulled or pushed to seal the terminal lead-out portion or the battery outer member. There is a case where the electrolyte injected into the thin battery leaks due to the peeling of the stop portion or the like, and the performance of the thin battery is deteriorated.
[0003]
DISCLOSURE OF THE INVENTION
An object of this invention is to provide the thin battery which has a structure strong with respect to the applied external force.
[0004]
In order to achieve the above object, according to the present invention, the outer peripheral edge of two sheet-shaped sealing means having at least a part of the outer peripheral edge having two or more synthetic resin layers laminated adjacent to each other is provided. A thin battery in which a power generation element is sealed inside by heat fusion, and a positive electrode terminal and a negative electrode terminal connected to the power generation element are led out from the outer peripheral edge portion. A thin battery having a corrugated structure between the synthetic resin layers laminated adjacent to each other is provided in at least a part of the attached sealing portion (see claim 1).
[0005]
In the present invention, the terminal lead-out portion or the battery exterior member is sealed by an external force applied from the outside by providing a corrugated structure between at least two or more adjacent synthetic resin layers of the thin battery sealing means. It becomes possible to remarkably reduce the peeling of the stop portion, and it is possible to obtain a thin battery having a structure strong against an applied external force.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0007]
Embodiment
FIG. 1A is a plan view showing an entire thin battery according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line BB in FIG. FIG. 2 is a cross-sectional view taken along the line CC in FIG. FIG. 3 is a terminal lead-out portion stress-elongation displacement graph according to the embodiment of the present invention. FIG. 1 shows one thin battery (unit battery), and an assembled battery having a desired voltage and capacity is formed by stacking a plurality of thin batteries 10.
[0008]
First, the overall configuration of the thin battery 10 according to the embodiment of the present invention will be described with reference to FIG. 1. The thin battery 10 of this example is a lithium-based thin secondary battery, and includes two positive electrode plates 101, Five separators 102, two negative plates 103, a positive terminal 104, a negative terminal 105, an upper battery exterior member 106 (sealing means), a lower battery exterior member 107 (sealing means), and a seal It is composed of a film 108 (sealing means) and an electrolyte (not shown). Among these, the positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolyte are particularly referred to as a power generation element 109.
[0009]
The number of positive plates 101, separators 102, and negative plates 103 is not limited in any way, and the power generation element 109 can be configured with one positive plate 101, three separators 102, and one negative plate 104. . The number of positive electrode plates, negative electrode plates, and separators can be selected and configured as necessary.
[0010]
The positive electrode plate 101 that constitutes the power generation element 109 includes, for example, 100 weight ratio of a positive electrode active material such as a metal oxide, a conductive material such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene. : A mixture of 3:10 is applied to both surfaces of a metal foil such as an aluminum foil as a positive electrode side current collector, dried, rolled, and then cut into a predetermined size. In addition, the mixing ratio of said aqueous dispersion of polytetrafluoroethylene is the solid content.
[0011]
As the positive electrode active material, for example, lithium nickelate (LiNiO)₂), Lithium manganate (LiMnO)₂), Lithium cobaltate (LiCoO)₂) And the like, and chalcogen (S, Se, Te) compounds. These materials are relatively easy to diffuse the heat generated in the thin battery, can reduce the expansion due to the expansion of the terminal due to the heat transfer to the terminal, and generate as much tensile stress as possible at the interface between the terminal and the seal film described later. It becomes possible to suppress.
[0012]
The negative electrode plate 103 constituting the power generation element 109 is made of a negative electrode active material that occludes and releases lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of an organic fired body is mixed at a solid content ratio of, for example, 100: 5, dried and then pulverized to support carbonized styrene butadiene rubber on the surface of carbon particles The resulting material is mixed with a binder such as an acrylic resin emulsion at a weight ratio of, for example, 100: 5, and this mixture is used as a metal foil such as nickel foil or copper foil as a negative electrode side current collector. These are coated on both sides, dried, rolled, and then cut into a predetermined size.
[0013]
In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. However, when used as a power source for an electric vehicle or the like, it is advantageous because there is no sudden drop in output.
[0014]
In addition, the separator 102 of the power generation element 109 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 described above, and may have a function of holding an electrolyte. The separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation, thereby blocking the current. It also has.
[0015]
The separator 102 of the present invention is not limited to a single-layer film such as polyolefin, but a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic nonwoven fabric can be used. . By forming the separator 102 in multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (rigidity improvement) function can be provided. Further, instead of the separator 102, a gel electrolyte or an intrinsic polymer electrolyte can be used.
[0016]
The above power generation element 109 is laminated in such an order that the positive electrode plate 101 and the negative electrode plate 103 are alternately arranged from above and the separator 102 is positioned between the positive electrode plate 101 and the negative electrode plate 103. The separators 102 are stacked one by one on the top and bottom. Each of the two positive plates 101 is connected to the positive terminal 104 made of metal foil via the positive current collector 104a, while the two negative plates 103 are connected to the negative current collector 105a. Is connected to the negative electrode terminal 105 which is also made of metal foil. The positive electrode terminal 104 and the negative electrode terminal 105 are not particularly limited as long as they are electrochemically stable metal materials. Examples of the positive electrode terminal 104 include aluminum, an aluminum alloy, copper, and nickel. Can include nickel, copper, stainless steel or iron. These metals are particularly suitable as components of thin batteries in terms of the resistance value, linear expansion coefficient, and resistivity of the metal, and even when the use temperature is changed, the generation of stress on the seal film described later is kept relatively small. I can do it. Further, both the positive electrode side current collector 104a and the negative electrode side current collector 105a in this example extend the aluminum foil, nickel foil, copper foil, and iron foil constituting the current collector of the positive electrode plate 104 and the negative electrode plate 105. However, the current collectors 104a and 105a can be formed of separate materials and parts.
[0017]
The power generation element 109 is sealed by the upper battery exterior member 106 and the lower battery exterior member 107 (sealing means). As shown in FIG. 2, the upper battery exterior member 106 according to the embodiment of the present invention includes a first resin layer 106a, a metal layer 106b, and a second resin layer from the positive terminal 104 side toward the outside of the thin battery. Three layers 106a to 106c are stacked in the order of 106c. The three layers 106a to 106c are laminated over the entire surface of the upper battery exterior member 106, and the first resin layer 106a is resistant to an electrolytic solution such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, and ionomer. And a resin film excellent in heat-fusibility. The second resin layer 106c is a resin film excellent in electrical insulation, such as a polyamide resin or a polyester resin. The metal layer 106b is, for example, a metal foil such as aluminum. Therefore, the upper battery exterior member 106 and the lower battery exterior member 107 are laminated with a resin such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer on one surface (inner surface of a thin battery) of a metal foil such as aluminum. Then, the other surface (the outer surface of the thin battery) is formed of a flexible material such as a resin-metal thin film laminate material in which a polyamide resin, a polyester resin, or the like is laminated.
[0018]
The lower battery exterior member 107 has the same structure as the upper battery exterior member 106, and as shown in FIG. 2, the first resin layer 107a, from the positive terminal 104 side toward the outside of the thin battery, Three layers 107a to 107c are stacked in the order of the metal layer 107b and the second resin layer 107c. Similar to the first resin layer 106a of the upper battery exterior member 106, the first resin layer 107a of the lower battery exterior member 107 is resistant to electrolyte solution and heat such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, and ionomer. It is a resin film excellent in fusing property. The metal layer 107b of the lower battery exterior member 107 is, for example, a metal foil such as aluminum, like the metal layer 106b of the upper battery exterior member 106. Similar to the second resin layer 106c of the upper battery exterior member 106, the second resin layer 107c of the lower battery exterior member 107 is a resin film excellent in electrical insulation, such as a polyamide resin or a polyester resin. . 2 shows a cross-sectional view of the positive electrode terminal 104, the cross-section on the negative electrode terminal side has the same structure. As described above, when the battery exterior member includes the metal layer in addition to the resin layer, the strength of the battery exterior member itself can be improved.
[0019]
Furthermore, in the embodiment of the present invention, in order to maintain the sealing performance in the thin battery 10, the electrolytic solution resistance and the heat-fusibility are provided at the portion where the positive electrode terminal 104 and the battery exterior member 106, 107 are in contact with each other. Is provided with a sealing film 108 (sealing means). Similarly, the negative electrode terminal 105 is led out from the other end portion of the battery exterior members 106 and 107, and the negative electrode terminal 105 and the battery exterior members 106 and 107 are in contact with each other as well as the positive electrode terminal 104 side. The sealing film 108 is interposed in the part to be performed.
[0020]
As described above, the battery exterior member and the seal film can be made of a resin such as polypropylene, modified polypropylene, polyethylene, modified polyethylene, or ionomer, thereby ensuring good fusion with a metal terminal. It becomes.
[0021]
These seal films 108 are composed of two resin layers, ie, an inner resin layer 108a and an outer resin layer 108b, which have different expansion / contraction ratios with respect to heat, for example, a linear expansion coefficient [1 / ° C.] and a heat shrinkage ratio [mm / mm]. It is configured. The inner resin layer 108 a is disposed so as to be in contact with the positive electrode terminal 104 and the negative electrode terminal 105, and the outer resin layer 108 b is the first resin layer 106 a of the upper battery outer member 106 and the first resin of the lower battery outer member 107. Arranged in contact with the layer 107a.
[0022]
The inner resin layer 108a is, for example, in the same manner as the first resin layers 106a and 107a of the battery exterior members 106 and 107 described above, for example, an electrolyte solution resistance such as polyethylene, modified polyethylene, polypropylene, modified propylene, and ionomer, and heat fusion. It is a resin film with excellent properties.
[0023]
On the other hand, the outer resin layer 108b is a resin layer having a lower expansion / contraction ratio with respect to heat than the inner resin layer 108a, such as crosslinked polyethylene, modified polyethylene, polypropylene, modified polypropylene, and ionomer. In order to obtain good fusing properties, it is preferable to use the same type of resin for the outer resin layer 108a and the inner resin layer 108a, and to use a resin in which only the outer resin layer 108b is crosslinked, for example, the inner resin layer 108a. When polypropylene is used for the outer resin layer, it is preferable to use crosslinked polypropylene for the outer resin layer 108b.
[0024]
When the battery exterior members 106 and 107 are sealed by thermal fusion, which will be described later, a corrugated interface is formed between the inner resin layer 108a and the outer resin layer 108b, which have different expansion / contraction ratios due to heat transfer. And an anchoring effect (anchor effect) at the interface can be obtained. Thus, by obtaining the anchor effect with the interface of the seal film as a corrugated structure, it becomes possible to firmly fuse the thermal fusion region of the terminal lead-out part or the battery exterior member, as shown in FIG. Compared with the case where the interface is formed in a straight line and the anchor effect cannot be obtained, it is possible to give the thin battery a strong structure against external force, and it is possible to ensure the long life of the thin battery. Become.
[0025]
Further, by using the outer resin layer 108b whose linear expansion coefficient is smaller than the linear expansion coefficient of the inner resin layer 108a, the inner resin layer positioned in the vicinity of the terminals 104 and 105 in the shrinkage of the sealing film 108 against heat. 108a extends following the shrinkage of the outer resin layer 108b, and a corrugated structure can be easily formed at the interface.
[0026]
In order to change the expansion / contraction ratio of the inner resin layer 108a and the outer resin layer 108b of the seal film 108 with respect to heat, that is, the linear expansion coefficient and the thermal contraction ratio, it is limited only to changing the crosslinking ratio of each resin described above. However, it is also possible to change the modification rate of each resin or change the type of each resin.
[0027]
In addition, the sealing film 108 may be provided not only in the vicinity of the positive electrode terminal and the negative electrode terminal, but also on the entire periphery of the heat-sealing region 110 of the battery exterior members 106 and 107. A strong structure can be imparted to the thin battery.
[0028]
In addition, the number of layers which comprise a battery exterior member and a sealing film is not limited above, It is possible to set the required number of layers suitably. Further, the terminal may be directly sealed by heat-sealing the first resin layer of the battery exterior member without interposing a seal film, or the seal film 108 may be included in the battery exterior member in advance. good.
[0029]
The battery exterior members 106 and 107 enclose the power generation element 109, the positive current collector 104a, a part of the positive terminal 104, the negative current collector 105a, and a part of the negative terminal 105, and the battery exterior member. After injecting a liquid electrolyte having a lithium salt such as lithium perchlorate or lithium borofluoride into an organic liquid solvent into the space formed by 106, 107, the outer surfaces of the upper battery outer member 106 and the lower battery outer member 107 are removed. The peripheral heat fusion region 110 is sealed by a method such as heat fusion.
[0030]
The thin battery 10 thus sealed preferably has a total thickness of 1 to 10 [mm]. By setting the thickness of the thin battery to 10 [mm] or less, it becomes difficult for heat to be trapped inside the thin battery, the possibility of transmitting stress to the interface between the terminal and the seal film is reduced, and the battery is thermally deteriorated. The impact of will also decrease. Further, by setting the thickness of the thin battery to 1 [mm] or more, a sufficient capacity can be ensured, and economic efficiency can be increased.
[0031]
Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC), but the organic liquid solvent of the present invention is not limited thereto, An organic liquid solvent prepared by mixing and preparing an ether solvent such as γ-butylactone (γ-BL) and dietoshikiethane (DEE) in an ester solvent can also be used.
[0032]
Hereinafter, an assembled battery configured by combining a plurality of the above-described thin batteries and a composite assembled battery configured by combining a plurality of the assembled batteries will be described.
[0033]
4A and 4B are diagrams showing a method for connecting a plurality of thin batteries according to an embodiment of the present invention. FIG. 4A shows parallel connection and FIG. 4B shows serial connection for comparison. FIG. 5 is a diagram showing another connection method for a plurality of thin batteries according to an embodiment of the present invention, FIG. 5 (A) shows parallel connection, and FIG. 5 (B) shows series connection for comparison. . 6 is a perspective view of an assembled battery including a plurality of thin batteries according to an embodiment of the present invention, FIG. 7A is a plan view of the assembled battery of FIG. 6, and FIG. 7B is an assembled battery of FIG. 7 (C) is a side view of the assembled battery of FIG. 6, FIG. 8 is a perspective view of a composite assembled battery composed of the assembled battery of FIG. 6, and FIG. 9 (A) is a composite assembled battery of FIG. 9B is a front view of the composite battery pack of FIG. 8, FIG. 9C is a side view of the composite battery pack of FIG. 8, and FIG. 10 shows the composite battery pack according to the embodiment of the present invention. The schematic diagram mounted in the vehicle is shown.
[0034]
When the assembled battery 20 having the plurality of thin batteries 10 is configured by electrically connecting the thin batteries 10 described above, two connection structures with the arrangement shown in FIGS. 4A and 5A are particularly applicable. A structure that is stronger against external force is added.
[0035]
As shown in FIG. 4A, the first connection structure is a direction in which the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are led out in the same direction. Thus, the first thin battery 10a and the second thin battery 10b are juxtaposed on substantially the same plane. Then, the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are electrically connected by the first bus bar 21a. Further, the negative terminal 105 of the first thin battery 10a and the negative terminal 105 of the second thin battery 10b are electrically connected by the second bus bar 21b.
[0036]
In the second connection structure, as shown in FIG. 5A, the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are led out in the same direction. Thus, the first thin battery 10a and the second thin battery 10b are stacked by bringing the vertically upward surface of the first thin battery 10a into contact with the vertically downward surface of the second thin battery 10b. Then, the positive electrode terminal 104 of the first thin battery 10a and the positive electrode terminal 104 of the second thin battery 10b are welded and electrically connected, and similarly, the negative electrode terminal 105 of the first thin battery 10a and the second terminal The thin-film battery 10b is electrically connected to the negative electrode terminal 105 by welding.
[0037]
When connected in series as shown in FIG. 4 (B) and FIG. 5 (B), the positive terminal 104 of each thin battery 10a, 10b is twisted in the opposite phase by the applied external force (FIG. 4 (B)). In FIG. 5B, the twisting direction is indicated by an arrow.) On the other hand, in the connection structure described above, the positive terminals 104 and the negative terminals 105 of the thin batteries 10a and 10b are connected to each other. Therefore, the stress generated in each of the thin batteries 10a and 10b has the same phase, the twist generated in the terminals 104 and 105 can be suppressed as much as possible, and the possibility that peeling occurs at the interface between the terminal and the seal film is reduced. . In addition, if the metal of the positive electrode terminal and the metal of the negative electrode terminal are different, the tensile stress generated in the terminal lead-out portion may be different and cause interfacial delamination. It is possible to substantially equalize the tensile stress generated in the part.
[0038]
FIGS. 6 and 7A to 7C show an assembled battery 20 constituted by 24 thin batteries 10 connected in parallel using, for example, the above-described two connection structures. The assembled battery 20 includes 24 thin batteries 10, assembled battery terminals 22 and 23, and an assembled battery cover 25. Although not shown in particular, the same-polarity terminals of each thin battery 10 are connected in parallel by the bus bars 21a and 21b in the above-described connection structure, and the first bus bar 21a connecting each positive terminal 104 is an assembled battery cover. 25 is connected to a substantially cylindrical assembled battery positive electrode terminal 22 led out from 25. Similarly, the second bus bar 21 b connecting each negative electrode terminal 105 is connected to a substantially cylindrical assembled battery negative terminal 23 that is led out from the assembled battery cover 25. When these connections are completed and 24 thin batteries 10 are inserted into the assembled battery cover 25, a space formed between the assembled battery cover 25 and the other components of the assembled battery 20 is formed. Filler 24 is filled and sealed. Furthermore, when thin batteries are stacked as a composite battery pack, which will be described later, in order to reduce vibration between the thin batteries as much as possible, external elastic bodies 26 are attached to the bottom four corners of the battery pack cover 25.
[0039]
8 and 9A to 9C show a composite battery pack 30 including six battery packs 20 electrically connected to the battery pack 20 shown in FIG. As shown in FIGS. 8 and 9A to 9C, the composite battery pack 30 is laminated so that the terminals 22 and 23 of the battery pack 20 face each other in the same direction. That is, the terminals 22 and 23 of the assembled battery 20 located at the m-th stage and the terminals 22 and 23 of the assembled battery 20 located at the (m + 1) -th stage are oriented in the same direction. M + 1-stage assembled batteries 20 are stacked (m: natural number). Then, the assembled battery positive terminals 22 of all assembled batteries 20 facing in the same direction are electrically connected by the external connection positive terminal 31 that connects the composite assembled battery 30 and the outside. Similarly, the assembled battery negative terminals 23 of all assembled batteries 20 facing in the same direction are electrically connected by the external connection negative terminal 32. As shown in the figure, the external connection positive electrode terminal 31 has a substantially rectangular flat plate shape, and a plurality of terminal connection holes having a diameter into which the assembled battery positive electrode terminal 22 can be inserted or press-fitted are processed. The terminal connection holes are processed at a pitch equal to the pitch between the assembled battery positive terminals 22 of the stacked assembled battery 20, and the terminal connection holes are similarly processed in the external connection negative terminal 32. Yes.
[0040]
Further, an insulating cover 33 made of an insulating material is provided so as to cover all the connected assembled battery terminals 22 and 23 so that the assembled battery terminals 22 and 23 are not exposed to the outside of the composite assembled battery 30. ing. In FIG. 8, the insulating cover 33 is depicted in a perspective view for convenience of explanation, and is not shown in FIG. Then, the six assembled batteries 20 stacked as described above are connected to both side surfaces by flat connecting members 34 and further fastened and fixed by fixing screws 35.
[0041]
As described above, it is required that a battery pack is formed in units of a predetermined number of thin batteries, and further a battery pack is combined with a predetermined number of battery packs in units of the battery pack. It becomes possible to easily obtain a composite battery pack suitable for capacity, voltage and the like. In addition, since the composite battery pack is configured without complicated connection, the failure rate of the composite battery pack due to poor connection can be reduced. Furthermore, when one thin battery constituting the composite assembled battery fails or deteriorates and the thin battery needs to be replaced, the assembled battery having the thin battery can be easily replaced.
[0042]
FIG. 10 is a schematic diagram showing an example in which the above-mentioned composite battery pack 30 is mounted on the vehicle 1 below the floor. As the vehicle 1 moves, a lot of vibration is generated in the vehicle. As shown in the figure, when the above-described composite assembled battery 30 is mounted on the vehicle, the possibility of interface peeling between the terminals of the thin battery and the seal film due to the vibration is significantly reduced, and the battery is effectively used in the vehicle. It becomes possible to utilize it.
[0043]
The number of thin batteries constituting the assembled battery, the number of assembled batteries constituting the composite battery, the connection method of the thin batteries constituting the assembled battery, and the connection method of the assembled batteries constituting the composite battery are described above. The number and connection method are not limited, and the number and connection method (series connection, parallel connection, series-parallel composite connection) can be appropriately set based on required electric capacity, voltage, and the like.
[0044]
The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[0045]
【Example】
Hereinafter, the effects of the present invention were confirmed by examples and comparative examples that further embody the present invention. The following examples are for confirming the effects of the thin battery used in the above-described embodiment.
[0046]
Example 1
In the thin battery of Example 1, the positive electrode active material was lithium manganate (LiMnO₂), Using amorphous carbon as the negative electrode active material, a mixed solution of propylene carbonate (PC) and ethyl methyl carbonate (EMC) as the electrolyte, aluminum (Al) as the positive electrode terminal, and nickel (Ni) as the negative electrode terminal. . In addition, a polymer resin composite film in which a nylon resin film 25 μm is used for the second resin layer, aluminum 40 μm is used for the metal layer, and a modified polypropylene resin film 50 μm is used for the first resin layer is used. The film was the fused surface. Further, a non-crosslinked polypropylene (PP) resin film and a cross-linked polypropylene resin film were used as a two-layer sealing film, and the non-crosslinked polypropylene resin film was brought into contact with the positive electrode terminal and the negative electrode terminal for crosslinking. The polypropylene resin film was brought into contact with the first resin layer of the battery exterior member and fused to produce a thin battery having a length of 140 [mm] × width of 80 [mm] × thickness of 4 [mm]. In addition, the linear expansion coefficient of the polypropylene used for this thin battery is 8.0 × 10^-5[1 / ° C.], thermal shrinkage rate is 0.025 [mm / mm], and the linear expansion coefficient of the crosslinked polypropylene of the seal film is 4.0 × 10^-5[1 / ° C.] and thermal shrinkage 0.01 [mm / mm].
[0047]
This thin battery was subjected to a tensile test. In the tensile test, the terminals of the thin battery, the upper battery exterior member, and the lower battery exterior member were tested in accordance with the tensile strength test method described in the automotive sealing material test method of JIS K6830. Here, the elongation amount during the tensile test was calculated, and the elongation ratio relative to the elongation amount of the reference sample in the test under the same conditions was calculated in%. The reference sample in the tensile test is a thin battery using a single-layer seal film of Comparative Example 1 described later.
[0048]
As a result, in Example 1, an allowable elongation of 190% with respect to the reference sample was confirmed. FIG. 11 shows a cross-sectional photograph of the terminal lead-out portion of the thin battery of Example 1. As shown in FIG. 11, it was confirmed that a corrugated structure was formed at the interface between the two layers of the polypropylene resin film constituting the seal film and the crosslinked polypropylene resin film.
[0049]
Comparative Example 1
As Comparative Example 1, a positive electrode terminal, a negative electrode terminal, a positive electrode active material, a negative electrode active material, an electrolyte solution, and a battery exterior member similar to those in Example 1 were used, and a single-layer seal film of a polypropylene resin film that was not crosslinked was used. A thin battery having a length of 140 [mm] × width of 80 [mm] × thickness of 4 [mm] was produced. The thin battery was subjected to a tensile test test under the same conditions as in the first example.
[0050]
As a result, since the comparative example 1 in the tensile test is used as a reference, the allowance for the elongation is 100%. FIG. 12 shows a cross-sectional photograph of the terminal lead-out portion of the thin battery of Comparative Example 1. As shown in FIG. 12, it was confirmed that a corrugated structure was not formed at the interface of the seal film.
[0051]
Consideration
Compared with the thin battery of Comparative Example 1, it is clear that the thin battery of Example 1 has a corrugated structure formed on the seal film, significantly improves the strength due to the anchor effect, and has a structure strong against the applied external force. It became.
[Brief description of the drawings]
FIG. 1A is a plan view showing an entire thin battery according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line BB in FIG.
FIG. 2 is a cross-sectional view taken along the line CC in FIG.
FIG. 3 is a terminal lead-out portion stress displacement graph according to an embodiment of the present invention.
4A and 4B are diagrams showing a connection structure of a plurality of thin batteries according to an embodiment of the present invention, in which FIG. 4A shows parallel connection and FIG. 4B shows serial connection for comparison.
5A and 5B are diagrams showing another connection structure of a plurality of thin batteries according to an embodiment of the present invention, where FIG. 5A shows parallel connection and FIG. 5B shows serial connection for comparison. Show.
FIG. 6 is a perspective view of an assembled battery including a plurality of thin batteries according to an embodiment of the present invention.
7A is a plan view of the assembled battery of FIG. 6, FIG. 7B is a front view of the assembled battery of FIG. 6, and FIG. 7C is a side view of the assembled battery of FIG. .
FIG. 8 is a perspective view of a composite battery pack constituted by the battery pack of FIG.
9A is a plan view of the composite battery of FIG. 8, FIG. 9B is a front view of the composite battery of FIG. 8, and FIG. 9C is a side view of the composite battery of FIG. It is.
FIG. 10 is a schematic view in which a composite battery pack according to an embodiment of the present invention is mounted on a vehicle.
11 shows a cross-sectional photograph of the terminal lead-out portion of the thin battery of Example 1. FIG.
12 shows a cross-sectional photograph of the terminal lead-out portion of the thin battery of Comparative Example 1. FIG.
[Explanation of symbols]
1 ... Vehicle
10 ... Thin battery
10a: first thin battery
10b ... second thin battery
101 ... Positive electrode plate
102 ... Separator
103 ... Negative electrode plate
104: Positive terminal
105 ... Negative terminal
106: Upper battery exterior member
106a ... 1st resin layer
106b ... metal layer
106c ... second resin layer
107 ... Lower battery exterior member
107a ... first resin layer
107b ... metal layer
107c ... second resin layer
108 ... Sealing film
109 ... Power generation element
110 ... heat fusion region
20 ... Battery
21a ... first bus bar
22b ... second bus bar
22 ... Positive electrode terminal for battery pack
23 ... Negative electrode terminal for battery pack
24 ... Filler
25 ... Battery cover
26. External elastic body
30 ... Composite battery pack
31 ... Positive terminal for external connection
32 ... Negative terminal for external connection
33 ... Insulation cover
34. Connecting member
35 ... Fixing screw

Claims (20)

The power generation element is sealed inside by heat-sealing the outer peripheral edge portions of two sheet-shaped sealing means having at least a part of the outer peripheral edge portions of two or more synthetic resin layers laminated adjacent to each other. Stop,
A thin battery in which a positive electrode terminal and a negative electrode terminal connected to the power generation element are led out from the outer periphery,
A thin battery in which at least a part of the heat-sealed sealing portion of the sealing means has a corrugated structure between the adjacent synthetic resin layers.   The thin battery according to claim 1, wherein the corrugated structure is formed between the adjacent synthetic resin layers by heat sealing the sealing portion.   The thin battery according to claim 1 or 2, wherein the sealing means further includes at least one metal layer.   The thin battery according to any one of claims 1 to 3, wherein the at least two or more synthetic resin layers stacked adjacent to each other include at least two or more synthetic resin layers having different linear expansion coefficients. The at least two or more synthetic resin layers having different linear expansion coefficients include a first synthetic resin layer in contact with the positive electrode terminal and the negative electrode terminal;
A second synthetic resin layer laminated adjacent to the first synthetic resin layer,
The thin battery according to claim 4, wherein the second synthetic resin layer has a smaller linear expansion coefficient than the first synthetic resin layer.   The thin battery according to claim 5, wherein the first synthetic resin layer includes a material selected from the group consisting of polypropylene, modified polypropylene, polyethylene, modified polyethylene, or ionomer.   The second synthetic resin layer includes a material selected from the group consisting of cross-linked polypropylene, cross-linked modified polypropylene, cross-linked polyethylene, cross-linked modified polyethylene, or cross-linked ionomer. The thin battery as described.   The thin battery according to any one of claims 5 to 7, wherein when the first synthetic resin layer includes polypropylene, the second synthetic resin layer includes crosslinked polypropylene.   The thin battery according to any one of claims 5 to 8, wherein when the first synthetic resin layer includes polyethylene, the second synthetic resin layer includes crosslinked polyethylene. The thin battery according to any one of claims 1 to 9, wherein the positive electrode terminal includes one or more components selected from the group consisting of aluminum, copper , and nickel.   The thin battery according to any one of claims 1 to 10, wherein the negative electrode terminal includes one or more components selected from the group consisting of iron, nickel, and copper.   The thickness of the said thin battery is 1-10 mm, The thin battery in any one of Claims 1-11. The power generation element has a positive electrode active material that functions as a positive electrode,
The thin battery according to claim 1, wherein the positive electrode active material is a lithium composite oxide.   The thin battery according to claim 13, wherein the lithium composite oxide is a lithium-manganese composite oxide. The power generation element has a negative electrode active material that functions as a negative electrode,
The thin battery according to claim 1, wherein the negative electrode active material is a carbon-based material.   The thin battery according to claim 15, wherein the carbon-based material is an amorphous carbon material. A plurality of the thin batteries according to any one of claims 1 to 16,
A battery assembly having a plurality of connecting means for electrically connecting one of the positive electrode terminal or the negative electrode terminal of one thin battery and the same polarity terminal or one of the other electrode terminals of the other thin battery,
The other thin battery is juxtaposed to the side of the one thin battery so that the positive terminal of the one thin battery and the same polarity terminal of the other thin battery are in the same direction,
The one connecting means electrically connects the positive terminal of the one thin battery and the positive terminal of the other thin battery,
An assembled battery including at least two or more thin batteries in which the negative terminal of the one thin battery and the negative terminal of the other thin battery are electrically connected by another connection means. An assembled battery having a plurality of thin batteries, wherein the thin batteries according to claim 1 are electrically connected,
Laminating the other thin battery on the upper part in the vertical direction of the one thin battery so that the positive electrode terminal of the one thin battery and the same polarity terminal of the other thin battery are in the same direction,
Electrically connecting the positive terminal of the one thin battery and the positive terminal of the other thin battery;
An assembled battery including at least two or more thin batteries in which the negative terminal of the one thin battery and the negative terminal of the other thin battery are electrically connected. A composite assembled battery comprising a plurality of assembled batteries, wherein the assembled batteries according to claim 17 or 18 are electrically connected in series, connected in parallel, or connected in series and parallel . A vehicle on which the composite assembled battery according to claim 19 is mounted.

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