Housing for energy storage module and energy storage module

Abstract

Provided is a housing for a power storage module which has excellent heat radiation properties, electrical insulation properties, strength, and the like.　The present invention is directed to a housing 1 for a power storage module, the housing 1 comprising a battery accommodation part 15 that is covered with a covering sheet 10, and being configured such that a plurality of batteries 2, in each of which a battery element is enclosed in a case, can be accommodated in the battery accommodation part 15. The covering sheet 10 is constituted by a lamination material L1 that is provided with: a barrier layer 51; and a heat bonding layer 52 which is made of a resin and which is laminated on the inner surface side of the barrier layer 51.

Description

[Technical Field]

[0001] The present invention relates to a housing for an electricity storage module such as a power module used when supplying power to motors of power tools, electric vehicles, electric bicycles, etc., or when storing renewable energy or emergency power sources, and also to an electricity storage module and a skin sheet for the electricity storage module. [Background technology]

[0002] Energy storage modules such as batteries that power the drive motors of electric vehicles and trains, as well as stationary energy storage modules for home and industrial use, require high output (high power) functionality because they require large amounts of electrical energy (power) in a short space of time.

[0003] On the other hand, the output of a single cell containing a pair of battery elements (bare cells) consisting of a positive and negative electrode is determined by the combination of active materials in the positive and negative electrodes that make up the battery, so there is a limit to the output, making it difficult to obtain high output. Therefore, in order to obtain the desired high output energy, it is common to adopt a power module or other energy storage module (battery assembly) in which multiple pairs of battery elements are arranged in series inside an outer casing for the energy storage module.

[0004] The power module disclosed in Patent Document 1 below is composed of an electricity storage device in which a laminate in which a pair of positive and negative electrode battery elements and separators are alternately arranged in series is sealed in an electrolyte solution inside an outer casing. This electricity storage device has a problem in that the electrolyte may get into the contact points between the electrodes of adjacent battery elements, making the contact points susceptible to corrosion.

[0005] The electricity storage module shown in Patent Document 2 is configured by housing multiple battery elements in a bag-shaped outer casing (housing) made by heat-sealing the outer peripheral edges of two laminate sheets (films) in which a heat-sealable resin is laminated to aluminum foil. In this electricity storage device, a tab lead is sandwiched between the outer peripheral edges of the two laminate sheets that serve as the outer casing and heat-sealed, and electricity is passed in and out via the tab lead. However, the heat-sealed portion of the tab lead in the laminate sheet has a weakness, and if a large amount of electricity flows through the tab lead, there is a risk of a short circuit between the tab lead and the aluminum foil of the laminate sheet, causing concerns about electrical insulation.

[0006] On the other hand, the power modules shown in Patent Documents 3 and 4 below are configured as an electricity storage module in which a plurality of unit cells, each of which is configured by sealing one battery element in a case, are arranged in series inside a housing. In these electricity storage modules, an electrolyte is sealed inside each battery case, and the electrodes of each unit cell are arranged outside the case, so that the electrolyte does not get into the contact points between the electrodes of adjacent unit cells, and corrosion at these contact points can be effectively prevented.

[0007] In such an electricity storage module having a plurality of unit cells, various improvements are made depending on the intended use and the like.

[0008] For example, the energy storage module disclosed in Patent Document 3 is configured by arranging a plurality of unit cells in a metal housing. Furthermore, the energy storage module disclosed in Patent Document 4 is configured by bundling a plurality of unit cells and packaging them with a heat-shrinkable resin film. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5515260 [Patent Document 2] Patent No. 5459398 [Patent Document 3] Patent No. 5057706 [Patent Document 4] Patent No. 5429773 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the electricity storage module disclosed in Patent Document 3 has a metal housing, which increases the weight and raises concerns about electrical insulation.

[0011] Furthermore, in the electricity storage module disclosed in Patent Document 4, the outer casing (housing) is made of a heat-shrinkable resin film, which causes concerns about heat dissipation and strength.

[0012] The preferred embodiments of the present invention have been made in light of the above and / or other deficiencies in the related art, and provide significant improvements over existing methods and / or apparatus.

[0013] The present invention has been made in view of the above-mentioned problems, and aims to provide a housing for a storage module, a storage module, and a skin sheet for a storage module that can improve heat dissipation, electrical insulation, and strength while achieving weight reduction.

[0014] Other objects and advantages of the present invention will be apparent from the following preferred embodiments. [Means for solving the problem]

[0015] In order to solve the above problems, the present invention comprises the following means.

[0016] [1] A housing for an electricity storage module, comprising a battery housing section covered with a skin sheet, and in which a plurality of unit cells, each having a battery element sealed in a case, are housed, The housing for the energy storage module is characterized in that the surface sheet is made of a laminate material including a barrier layer and a resinous thermal adhesive layer laminated on the inner surface side of the barrier layer.

[0017] [2] The barrier layer is made of aluminum and has an elongation of 15% to 35%, a Vickers hardness of 20 to 60, and a modulus of longitudinal elasticity of 60 kN / mm 2 ~80kN / mm 2 2. The housing for a storage module according to claim 1, wherein the housing is adjusted to:

[0018] [3] The housing for the storage module according to the preceding item 1 or 2, wherein the inner surface of the battery accommodating section is configured so as to be able to be fixed to the outer surface of the unit cell.

[0019] [4] The housing for the storage module according to claim 1 or 2, wherein a battery fixing layer made of resin that can be thermally bonded to the outer surface of the unit cell is provided on the inner surface side of the barrier layer.

[0020] [5] The housing for a storage module according to the preceding item 1 or 2, wherein the thermal adhesive layer is configured as a thermal fusion layer, and the thermal fusion layer has insulating properties and a thickness set to 80 μm to 200 μm.

[0021] [6] The housing for a storage module according to the preceding paragraph 1 or 2, wherein the two overlapping skin sheets are formed by joining the outer peripheral edges of each other.

[0022] [7] The housing for a storage module according to the above item 1 or 2, wherein the thickness of the barrier layer of the laminate material is set to 50 μm to 200 μm.

[0023] [8] The housing for a storage module according to the preceding item 1 or 2, wherein the thermal adhesive layer of the laminate material is made of an unstretched film made of a thermoplastic resin or a coating material made of a thermoplastic resin.

[0024] [9] The housing for a storage module according to the above item 1 or 2, wherein the thickness of the thermal adhesive layer of the laminate material is set to 5 μm to 100 μm.

[0025]

[10] The housing for a storage module according to the preceding paragraph 1 or 2, wherein the laminate material constituting the skin sheet includes a resin protective layer laminated on the outer surface side of the barrier layer.

[0026]

[11] The housing for a storage module according to the preceding paragraph 10, wherein the protective layer of the laminate material is made of a biaxially stretched film.

[0027]

[12] The housing for a storage module according to the above item 1 or 2, wherein a base layer is formed on at least one surface of the barrier layer of the laminate material.

[0028]

[13] Equipped with the housing described in the preceding paragraph 1 or 2, A storage module characterized in that a plurality of batteries, each having a battery element sealed in a case, are housed in the battery housing portion of the housing.

[0029]

[14] A skin sheet for an electricity storage module that houses a plurality of unit cells, each having a battery element sealed in a case, comprising: A surface sheet for a power storage module, characterized in that it is made of a laminate material having a barrier layer and a resinous thermal adhesive layer laminated on the inner surface side of the barrier layer.

[0030]

[15] The barrier layer is made of aluminum and has an elongation of 15% to 35%, a Vickers hardness of 20 to 60, and a modulus of longitudinal elasticity of 60 kN / mm 2 ~80kN / mm 2 15. The skin sheet for an electricity storage module according to item 14 above, which is adjusted to:

[0031] [1-1] A housing for an electricity storage module, comprising a battery housing section covered with a skin sheet, and configured so that a plurality of batteries, each having a battery element sealed in a case, can be housed in the battery housing section, the surface sheet is made of a laminate material including a metal barrier layer and a resin thermal adhesive layer laminated on the inner surface of the barrier layer, The housing for the storage module is characterized in that a cutout hole is provided in the skin sheet, and the cutout hole is configured as an opening for inputting and outputting electricity to and from the battery.

[0032] [1-2] The housing for a storage module according to the preceding paragraph 1-1, wherein the two overlapping skin sheets are formed by joining the outer peripheral edges of each other.

[0033] [1-3] The housing for a storage module according to the preceding paragraph 1-1 or 1-2, wherein the openings are provided in two or more places.

[0034] [1-4] The housing for a storage module according to any one of the above items 1-1 to 1-3, wherein the thickness of the barrier layer of the laminate material is set to 50 μm to 200 μm.

[0035] [1-5] The housing for a storage module according to any one of the preceding items 1-1 to 1-4, wherein the thermal adhesive layer of the laminate material is made of an unstretched film made of a thermoplastic resin or a coating material made of a thermoplastic resin.

[0036] [1-6] The housing for a storage module according to any one of the above items 1-1 to 1-5, wherein the thickness of the thermal adhesive layer of the laminate material is set to 5 μm to 100 μm.

[0037] [1-7] The housing for a storage module according to any one of the preceding paragraphs 1-1 to 1-6, wherein the laminate material constituting the surface sheet includes a resin protective layer laminated on the outer surface side of the barrier layer.

[0038] [1-8] The housing for a storage module according to the preceding paragraph 1-7, wherein the protective layer of the laminate material is made of a biaxially stretched film.

[0039] [1-9] The housing for a storage module according to any one of the above items 1-1 to 1-8, wherein a base layer is formed on at least one surface of the barrier layer of the laminate material.

[0040] [1-10] A housing according to any one of the preceding paragraphs 1-1 to 1-9 is provided, A storage module characterized in that a plurality of batteries, each having a battery element sealed in a case, are housed in a battery housing portion of the housing.

[0041] [1-11] The energy storage module according to the preceding paragraph 1-10, wherein one end of a lead terminal is electrically connected to the electrode of the end battery among the batteries arranged in series, and the other end of the lead terminal is arranged corresponding to the opening.

[0042] [1-12] An electrode member is disposed between the inner peripheral end surface of the battery accommodating portion and the battery at the end, 12. The electricity storage module according to item 1-11, wherein the electrode member includes a resin block member and the lead terminals are held by having intermediate portions embedded in the block member.

[0043] [1-13] The energy storage module according to the preceding paragraph 1-12, wherein the peripheral edge of the opening in the skin sheet is thermally bonded to the outer surface of the block member.

[0044] [2-1] A housing for an electricity storage module, which includes a battery housing section covered with a skin sheet, and is configured so that a plurality of unit cells, each having a battery element sealed in a case, can be housed in the battery housing section, the surface sheet is made of a laminate material including a barrier layer, a resin thermal adhesive layer laminated on the inner surface side of the barrier layer, and a resin protective layer laminated on the outer surface side of the barrier layer, The barrier layer is made of aluminum selected from 1000 series, 3000 series, 5000 series, and 8000 series, and has an elongation of 15% to 35%, a Vickers hardness of 20 to 60, and a modulus of longitudinal elasticity of 60 kN / mm 2 ~80kN / mm 2 A housing for a power storage module, characterized in that the housing is adjusted to

[0045] [2-2] The housing for the storage module according to the preceding paragraph 2-1, wherein the inner surface of the battery housing portion is configured so as to be able to be fixed to the outer surface of the unit cell.

[0046] [2-3] The housing for a storage module according to the above item 2-1 or 2-2, wherein the thickness of the barrier layer is adjusted to 40 μm to 200 μm.

[0047] [2-4] The housing for a storage module according to any one of the above items 2-1 to 2-3, wherein the barrier layer is made of tempered O-grade aluminum.

[0048] [2-5] The housing for a storage battery module according to any one of the above items 2-1 to 2-4, wherein the two overlapping skin sheets are formed by joining the outer peripheral edges of each other.

[0049] [2-6] A housing according to any one of the preceding paragraphs 2-1 to 2-5 is provided, A storage module characterized in that a plurality of unit cells, each having a battery element sealed in a case, are housed in a battery housing portion of the housing.

[0050] [2-7] The energy storage module according to the preceding paragraph 2-6, wherein the inner surface of the battery housing portion is fixed to the outer surface of the cell.

[0051] [3-1] A housing for an electricity storage module, comprising a battery housing section covered with a skin sheet, and configured so that a plurality of unit cells, each having a battery element sealed in a case, can be housed in the battery housing section, the skin sheet is made of a laminate material including a barrier layer made of metal foil and a battery fastening layer made of resin that is laminated on the inner side of the barrier layer and can be thermally bonded to the outer surface of the unit cells.

[0052] [3-2] The housing for a storage module according to the above item 3-1, wherein the battery fixing layer has a melting point of 80°C to 120°C.

[0053] [3-3] The housing for a storage module according to the above item 1 or 2, wherein the battery fixing layer is made of a resin containing an olefin polymer having a carboxylic acid.

[0054] [3-4] The housing for a storage module according to any one of the preceding items 3-1 to 3-3, wherein a thermal adhesive layer made of a resin having a melting point 10°C or more higher than that of the battery fixing layer is provided between the barrier layer and the battery fixing layer.

[0055] [3-5] The housing for a storage module according to the preceding paragraph 3-4, wherein a protective layer made of a resin having a melting point 20° C. or more higher than that of the thermal adhesive layer is provided on the outer surface side of the barrier layer.

[0056] [3-6] An electricity storage module including the housing according to any one of the preceding paragraphs 3-1 to 3-5, in which a plurality of unit cells, each having a battery element sealed in a case, are housed in the battery housing portion of the housing, The battery module is characterized in that the battery fastening layer is fixed to the outer surface of the battery cell by thermal adhesion.

[0057] [4-1] A housing for an electricity storage module, comprising a battery housing section covered with a skin sheet, and configured so that a plurality of unit cells, each having a battery element sealed in a case, can be housed in the battery housing section, the surface sheet is made of a laminate material having at least a barrier layer made of metal foil and a heat-sealing layer made of resin laminated on the inner surface side of the barrier layer, The housing for a storage module is characterized in that the heat-sealing layer has insulating properties and a thickness set to 80 μm to 200 μm.

[0058] [4-2] The heat-sealing layer is composed of a multi-layer body including at least two layers: a low-melting-point layer and a high-melting-point layer having a melting point higher than that of the low-melting-point layer; The housing for a storage module according to the preceding item 4-1, wherein the low-melting-point layer of the multilayer body is disposed on the innermost side of the multilayer body.

[0059] [4-3] The housing for a storage module according to the preceding paragraph 4-2, wherein the multilayer body includes the high-melting-point layer having a thickness of 50 μm or more.

[0060] [4-4] The thermal adhesive layer is laminated on the barrier layer via an adhesive layer, The housing for a storage battery module according to any one of the above items 4-1 to 4-3, wherein the adhesive layer has insulating properties.

[0061] [4-5] The housing for a storage module according to the preceding paragraph 4-4, wherein the adhesive layer contains an insulating filler of an inorganic oxide.

[0062] [4-6] The housing for a storage module according to any one of the above items 4-1 to 4-5, wherein a protective layer made of a heat-resistant resin is laminated on the outer surface side of the barrier layer.

[0063] [4-7] A storage module comprising a housing according to any one of the preceding paragraphs 4-1 to 4-6, characterized in that a plurality of single cells, each having a battery element sealed in a case, are housed in the battery housing section of the housing.

[0064] [4-8] A surface sheet for an electricity storage module that houses a plurality of single cells in which battery elements are sealed in a case, The laminated material includes a metal foil barrier layer and a resin heat-sealing layer laminated on the inner surface of the barrier layer. The heat-sealing layer is an insulating surface sheet having a thickness set to 80 μm to 200 μm. [Effects of the Invention]

[0065] According to the housing for the electricity storage module of the inventions [1] to

[12] , it is possible to improve heat dissipation, electrical insulation, and strength while reducing the weight.

[0066] According to the energy storage module of the invention

[13] , it is possible to improve heat dissipation, electrical insulation, and strength while reducing the weight.

[0067] According to the inventions

[14] and

[15] , the surface sheet for the power storage module can be made lighter while improving heat dissipation, electrical insulation, and strength.

[0068] The energy storage module housing of invention [1-1] is constructed with a surface sheet made of a laminate material, which allows for lighter weight and improved electrical insulation compared to metal housings. Furthermore, the metal barrier layer of the surface sheet ensures heat conductivity and strength, improving heat dissipation and strength. Furthermore, the energy storage module of the present invention has cutout openings formed in the surface sheet, through which electricity is transferred to and from the battery. Unlike cases where electricity is transferred via tab leads, this prevents problems such as short-circuiting of electrodes, etc., with the barrier layer of the surface sheet, even when a large current is transferred. This further improves electrical insulation.

[0069] According to the housing for the storage module of the invention [1-2], since it is formed by overlapping two skin sheets, it can be formed into an appropriate shape, and a storage module with the desired performance can be reliably manufactured.

[0070] According to the housing for the energy storage module of the invention [1-3], since there are two or more openings, the electrical input / output ports can be formed separately for the positive and negative electrodes, and short circuits can be more reliably prevented.

[0071] According to the housing for a storage module of the invention [1-4], the barrier layer of the skin sheet is set to a specific thickness, so that the skin sheet can be formed well while ensuring sufficient strength.

[0072] According to the housing for the energy storage module of the invention [1-5], the thermal adhesive layer of the skin sheet is made of a specific resin, so that the thermal adhesive process of the skin sheet can be carried out reliably, the built-in battery can be securely held, and short circuits due to misalignment of the battery, etc. can be reliably prevented.

[0073] According to the housing for the energy storage module of the invention [1-6], the thermal adhesive layer of the skin sheet is set to a specific thickness, which ensures good insulation and sealing properties while reliably preventing inadvertent exposure of the barrier layer.

[0074] According to the housing for the storage module of the invention [1-7], the insulating properties of the housing itself are improved by laminating a resin protective layer on the surface sheet, and the weather resistance is also improved.

[0075] According to the housing for the energy storage module of the invention [1-8], the protective layer of the skin sheet is made of a specific resin, which makes it possible to obtain high strength, for example, improve puncture resistance, and further improve barrier properties and corrosion resistance.

[0076] According to the housing for the energy storage module of the invention [1-9], a base layer is provided on the barrier layer of the skin sheet, so that the resin layers such as the thermal adhesive layer and the protective layer laminated on the barrier layer are less likely to peel off, preventing delamination. This more reliably prevents exposure of the barrier layer, further improving the barrier properties, and more reliably preventing corrosion of the barrier layer.

[0077] According to the electricity storage module of the invention [1-10], similarly to the above, it is possible to reduce the weight while improving the heat dissipation, electrical insulation, and strength.

[0078] According to the electricity storage module of the inventions [1-11] and [1-12], electricity can be reliably supplied to and discharged from the battery.

[0079] According to the energy storage module of the invention [1-13], the periphery of the opening is sealed, so that airtightness can be ensured.

[0080] The energy storage module housing of invention [2-1] is constructed with a surface sheet made of a laminate material, which allows for lighter weight and improved electrical insulation compared to metal housings. Furthermore, the aluminum barrier layer of the surface sheet has high thermal conductivity, improving heat dissipation. Furthermore, the energy storage module of the present invention has a barrier layer of specific aluminum, which ensures good formability and improves strength and shape retention after molding.

[0081] According to the housing for the energy storage module of the invention [2-2], the housing is configured so that the single cells can be fixed, and therefore the single cells can be held in a stable state. Even if the housing is subjected to external shock or vibration, the displacement of the single cells can be prevented, and the occurrence of short circuits, etc. can be effectively prevented.

[0082] According to the housing for a storage module of the invention [2-3], the barrier layer of the surface sheet is set to a specific thickness, so that the above-mentioned effects can be obtained more reliably.

[0083] According to the housing for a storage module of the invention [2-4], the barrier layer is made of an O material, which further improves formability.

[0084] According to the housing for a storage module of the invention [2-5], since it is formed by overlapping two skin sheets, it can be formed into an appropriate shape, and a storage module with the desired performance can be reliably formed.

[0085] According to the electricity storage module of the invention [2-6], similarly to the above, it is possible to achieve weight reduction while improving heat dissipation, electrical insulation, formability, strength, and shape retention.

[0086] According to the energy storage module of the invention [2-7], the cells are fixed in place, so that the cells can be held in a stable state, and even if the cells are subjected to external shocks or vibrations, the cells can be prevented from shifting position, and the occurrence of short circuits, etc. can be effectively prevented.

[0087] According to the energy storage module casing of invention [3-1], a battery fastening layer that can be thermally bonded to the outer surface of the battery cell is provided on the inner circumferential surface of the battery accommodating section, and the battery fastening layer can be thermally bonded to the battery cell, thereby stably fixing the battery cell. Therefore, even if the battery cell is subjected to vibration or impact, it is possible to reliably prevent displacement or deformation of the battery cell, and prevent short circuits and other problems that may result from such displacement or deformation. Furthermore, because the energy storage module casing is made of a skin sheet made of a laminate material, it is lighter in weight and has improved electrical insulation compared to a metal casing, and it also has improved heat dissipation and strength compared to a casing made of a heat-shrinkable resin film.

[0088] According to the housing for the energy storage module of the invention [3-2], a battery fixing layer having a specific melting point is used, so that the battery fixing process at a relatively high temperature is not required, and the adverse effects of heat on the single battery are avoided, while the fixed state with the single battery can be reliably maintained under normal temperature environments.

[0089] According to the housing for the energy storage module of the invention [3-3], the battery fixing layer is made of a resin containing an olefin polymer having a carboxylic acid, so that the battery fixing layer has high adhesion to the unit cells, and the skin sheet can be reliably thermally bonded to the unit cells, thereby more reliably preventing displacement or deformation of the unit cells.

[0090] According to the housing for the energy storage module of the invention [3-4], a thermal adhesive layer is provided between the barrier layer and the battery fixing layer, so that even if the battery fixing layer melts more than expected during heat treatment and becomes thinner, the thermal adhesive layer can ensure sufficient insulation.

[0091] According to the housing for the electricity storage module of the invention [3-5], a protective layer with excellent heat resistance is formed on the outer surface side of the barrier layer, so that the heat resistance can be further improved.

[0092] According to the inventions [3-6], the invention specifies a storage module in which a cell is housed in the housing of the invention described above, and therefore, the same effects as those described above can be obtained.

[0093] According to the housing for a storage module of invention [4-1], an insulating resin of a predetermined thickness is used as the heat-sealing layer arranged on the inner side of the skin sheet, so that the heat-sealing layer 6 can be reliably maintained even against high temperatures during heat sealing of the heat-sealing layer and Joule heat during power supply, ensuring sufficient insulation. Furthermore, because this housing for a storage module is made of a skin sheet made of a laminate material, it can be made lighter and have improved electrical insulation compared to housings made of metal or resin.

[0094] According to the housing for the energy storage module of the invention [4-2], the heat-sealing layer is made up of a multi-layer body with two or more layers having different melting points, and the low-melting-point layer is arranged on the innermost side of the multi-layer body. Therefore, by melting and heat-sealing the low-melting-point layer during heat sealing, the sealing process can be carried out reliably while the high-melting-point layer can be sufficiently left intact, and insulation can be more reliably ensured.

[0095] According to the housing for the energy storage module of the invention [4-3], the thickness of the high-melting point layer is equal to or greater than a predetermined value, so that the high-melting point layer can be more reliably retained when electricity is applied or when heat-sealing, thereby ensuring even better insulation properties.

[0096] According to the housing for the energy storage module of inventions [4-4] and [4-5], an insulating adhesive is used as the inner adhesive layer for adhering the heat-sealing layer to the barrier layer, thereby further improving the insulation properties.

[0097] According to the housing for the energy storage module of invention [4-6], a heat-resistant protective layer is laminated on the outer surface of the barrier layer, which not only improves heat resistance but also prevents external electrodes such as tab leads drawn out from the housed cells from coming into contact with the barrier layer on the outer surface of the housing, ensuring insulation between the external electrodes and the barrier layer.

[0098] According to the inventions [4-7], the invention specifies a storage module in which a cell is housed in the housing of the invention, and therefore, the same effects as those described above can be obtained.

[0099] According to the invention [4-8], the surface sheet in the housing of the above invention is specified, so that the same effect as above can be obtained. [Brief explanation of the drawings]

[0100] [Figure 1A] FIG. 1A is a perspective view showing an electricity storage module according to embodiment 1-1 of the present invention. [Figure 1B] FIG. 1B is a side cross-sectional view showing the electricity storage module of embodiment 1-1. [Figure 1C] FIG. 1C is an exploded perspective view of the electricity storage module of embodiment 1-1. [Figure 1D] FIG. 1D is a block diagram for explaining a laminate material applied to the electricity storage module of embodiment 1-1. [Figure 1E] FIG. 1E is a perspective view showing an electrode member applied to the electricity storage module of embodiment 1-1. [Figure 1F] FIG. 1F is a perspective view showing an electricity storage module according to embodiment 1-2 of the present invention. [Figure 1G] FIG. 1G is a side cross-sectional view showing the electricity storage module of embodiment 1-2. [Figure 1H] FIG. 1H is an exploded perspective view of the electricity storage module of embodiment 1-2. [Figure 1I] FIG. 1I is a perspective view showing an electrode member applied to the electricity storage module of embodiment 1-2. [Figure 1J] FIG. 1J is a perspective view showing a conventional type electricity storage module of Comparative Example 1-1. [Figure 1K] FIG. 1K is a side cross-sectional view showing the electricity storage module of Comparative Example 1-1. [Figure 1L] FIG. 1L is an exploded perspective view of the electricity storage module of Comparative Example 1-1. [Figure 2A] FIG. 2A is a perspective view showing an electricity storage module according to a second embodiment of the present invention. [Figure 2B] FIG. 2B is a side cross-sectional view showing the electricity storage module of the second embodiment. [Figure 2C] FIG. 2C is an exploded perspective view of the energy storage module of the second embodiment. [Figure 2D] FIG. 2D is a block diagram illustrating a laminate material applied to the electricity storage module of the second embodiment. [Figure 3A] FIG. 3A is a perspective view showing an electricity storage module according to a third embodiment of the present invention. [Figure 3B] FIG. 3B is a side cross-sectional view showing the electricity storage module of the third embodiment. [Figure 3C] 3C is an exploded perspective view of the energy storage module of the third embodiment. FIG. [Figure 3D] FIG. 3D is a schematic cross-sectional view illustrating an example of a laminate material that can be applied to the electricity storage module of embodiment 3. As shown in FIG. [Figure 3E] FIG. 3E is a schematic cross-sectional view illustrating another example of a laminate material that can be applied to the electricity storage module of embodiment 3. As shown in FIG. [Figure 4A] FIG. 4A is a perspective view showing an electricity storage module according to a fourth embodiment of the present invention. [Figure 4B] FIG. 4B is a side cross-sectional view showing the electricity storage module of the fourth embodiment. [Figure 4C] FIG. 4C is an exploded perspective view of the electricity storage module of the fourth embodiment. [Figure 4D] FIG. 4D is a schematic cross-sectional view illustrating a laminate material applied to the electricity storage module of embodiment 4. As shown in FIG. [Figure 4E] FIG. 4E is a schematic cross-sectional view showing an example of a heat-sealing layer of the laminate material of the fourth embodiment. [Figure 4F] FIG. 4F is a cross-sectional view for explaining the power storage module model of the example. [Figure 4G] FIG. 4G is a perspective view for explaining the storage module model of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0101] <Embodiment 1-1> 1A to 1C are diagrams showing an energy storage module according to embodiment 1-1 of the present invention. In the following description, to facilitate understanding of the invention, the left-right direction in Fig. 1B will be referred to as the "front-rear direction (length direction)", the up-down direction in Fig. 1B will be referred to as the "up-down direction (thickness direction)", and the direction perpendicular to the plane of Fig. 1B will be referred to as the "width direction (left-right direction)".

[0102] As shown in FIGS. 1A to 1C, the energy storage module of this embodiment includes, as basic components, a housing (energy storage module housing) 1 as a casing (container), and a cell 2 and an electrode member 3 housed in the housing 1.

[0103] The housing 1 is composed of two skin sheets 10, one above the other. The skin sheets 10 are made of a laminate material L1, which will be described later, and are formed using techniques such as deep drawing and extrusion molding. The upper skin sheet 10 has a shape that is upside down compared to the lower skin sheet 10, and both skin sheets 10 have substantially the same shape.

[0104] In this embodiment, the lower skin sheet 10 has a downward recess formed over the entire middle region except for the outer peripheral edge, forming a rectangular parallelepiped recess 11, and an outwardly protruding flange 12 is integrally formed on the outer periphery of the opening edge of the recess 11.

[0105] As described above, the upper skin sheet 10 has a shape obtained by inverting the lower skin sheet 10 upside down, with a rectangular parallelepiped recessed portion 11 formed to bulge upward, and an outwardly protruding flange portion 12 integrally formed on the outer periphery of the recessed portion (bulge) 11. The upper skin sheet 10 has circular openings 16 formed at both ends in the front-to-rear direction of the recessed portion (bulge) 11. The openings 16 are formed by cutting out holes formed by partially cutting out the skin sheet 10.

[0106] The surface sheet 10 is made of a laminate material L1 which is a laminate sheet or film having flexibility and pliability.

[0107] 1D, the laminate material L1 includes a barrier layer 51 made of metal (metal foil), a heat-sealable thermal adhesive layer 52 laminated via an adhesive on one surface (inner surface) of the barrier layer 51, and a heat-resistant protective layer 53 laminated via an adhesive on the other surface (outer surface) of the barrier layer 51. In this embodiment, the term "foil" is used to include a film, a sheet, and a thin plate.

[0108] Aluminum foil, copper foil, stainless steel foil, nickel foil, titanium foil, nickel-plated foil (e.g., nickel- and copper-clad metal), etc. can be suitably used as the barrier layer 51. In this embodiment, the terms "aluminum," "copper," "nickel," and "titanium" also include alloys thereof.

[0109] The barrier layer 51 preferably has a thickness of 5 μm to 100 μm, more preferably 9 μm to 50 μm. That is, when the thickness of the barrier layer 51 is set to the above-mentioned specific thickness, it is possible to improve moldability while ensuring sufficient strength and barrier properties. In other words, if the thickness of the barrier layer 51 is too thin, it may not be possible to obtain the desired barrier properties and strength, and conversely, if the thickness of the barrier layer 51 is too thick, it may be less flexible and less moldable.

[0110] It is preferable to provide an underlayer on one or both sides of the barrier layer 51. The underlayer is preferably a chemical conversion coating formed by chromate treatment, silicate treatment, zirconium-based chemical conversion treatment, or the like.

[0111] The amount of the undercoat layer varies depending on the treatment method. For example, the amount of chromium applied to one side of a metal foil during chemical conversion treatment is 0.1 mg / m. 2 ~50mg / m 2It is recommended to set it at 2 mg / m 2 ~20mg / m 2 It is better to set it to .

[0112] When a base layer is formed on the barrier layer 51 in this manner, the resin layers such as the thermal adhesive layer 52 and the protective layer 53 laminated on the barrier layer 51 are less likely to peel off, preventing delamination. This reliably prevents exposure of the metallic barrier layer 51, improves the barrier properties, and effectively prevents corrosion of the barrier layer 51.

[0113] It is preferable to use a thermoplastic non-stretchable resin for the thermal adhesive layer 52. For example, it may be formed by attaching a film of non-stretchable resin such as non-stretchable polypropylene (CPP), polyethylene (LDPE, LLDPE, HDPE, etc.), acid-modified polyolefin resin, or by forming a coating layer coated with the above non-stretchable resin.

[0114] The thickness of the thermal adhesive layer 52 is preferably set to 5 μm to 150 μm, and more preferably set to 30 μm to 100 μm.

[0115] When the above-mentioned specific resin and thickness are used for the thermal adhesive layer 52, good thermal adhesion can be ensured, and the upper and lower skin sheets 10 can be firmly thermally fused together, and the skin sheets 10 and the electrode members 3a, 3b can be firmly fixed together, so that the cells 2 can be reliably fixed within the skin sheet 10, i.e., within the housing 1, and misalignment of the cells 2 and the lead wires 21a, 21b (described below) connected to the cells 2 can be reliably prevented, thereby reliably preventing the occurrence of defects such as short circuits. Furthermore, the thermal adhesive layer 52 is less likely to flow out during thermal fusion, preventing exposure of the metallic barrier layer 51 and improving insulation and corrosion resistance.

[0116] The protective layer 53 is preferably formed by adhering a biaxially oriented film, such as a biaxially oriented polyester film such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyethylene naphthalate (PEN), a biaxially oriented polyamide (ONY) film such as PA6 or PA66, or a biaxially oriented polypropylene (OPP) film.

[0117] The thickness of the protective layer 53 is preferably set to 5 μm to 100 μm, and more preferably set to 9 μm to 50 μm.

[0118] When the protective layer 53 is made of the above-mentioned specific resin and has the above-mentioned thickness, the protective layer 53 can have sufficient strength, can have improved puncture resistance, can prevent exposure of the metallic barrier layer 51, and can further improve electrical insulation and corrosion resistance.

[0119] The laminate material L1 having the above configuration is used as the sheet material for the upper and lower skin sheets, and this sheet material is recessed and cut to form the skin sheet 10. Furthermore, as described above, the upper skin sheet 10 has openings 16, which are cutout holes, formed at both ends of the recess 11. Then, as will be described later, the flanges 12 of the upper and lower skin sheets 10 are thermally fused (thermally adhered) to each other to form the energy storage module housing 1. In this housing 1, the recesses 11 of the upper and lower skin sheets 10 form a rectangular parallelepiped battery housing section 15.

[0120] Electrode members 3a and 3b are disposed on both ends of the battery accommodating section 15. As shown in Fig. 1E(a), the electrode member 3a is on the positive electrode side, and as shown in Fig. 1E(b), the electrode member 3b is on the negative electrode side.

[0121] The electrode members 3 a and 3 b each include a rectangular parallelepiped block member 31 that can be fitted into both ends of the battery housing portion 15 , and a lead terminal 32 that is embedded in the block member 31 .

[0122] The block member 31 is made of a molded product of a heat-sealable resin. As the heat-sealable resin, it is preferable to use the same type of resin as that of the heat-adhesive layer 52 of the laminate material L1.

[0123] The lead terminal 32 is arranged so that one end thereof is exposed on one of the front and rear surfaces of the block member 31, the middle position thereof is bent upward by 90° within the block member 31, and the other end thereof is exposed on the top surface of the block member 31.

[0124] In this embodiment, as shown in FIG. 1E(a), an aluminum rod is used as the lead terminal 32 of the positive electrode member 3a, and as shown in FIG. 1E(b), a copper rod is used as the lead terminal 32 of the negative electrode member 3b.

[0125] In this embodiment, the electrode members 3a and 3b can be produced by, for example, insert molding in which the lead terminals 32 are used as insert members and then injection molded. Needless to say, the method for producing the electrode members 3a and 3b is not limited.

[0126] 1C, the positive electrode member 3a is accommodated on one side (right side) of the recess 11 in the lower skin sheet 10, and the negative electrode member 3b is accommodated on the other side (left side). In this accommodated state, the electrode members 3a, 3b are arranged so that the surfaces on which one end of each lead terminal 32 is exposed face inward and face each other. The other end of each lead terminal 32 is open on the top surface of the block member 31.

[0127] 1B and 1C, the cell 2 used in this embodiment is a commercially available 9V dry cell. Needless to say, this cell 2 has a rectangular shape with a positive electrode and a negative electrode arranged side by side on one side.

[0128] In the present invention, any battery can be used as the battery such as a single cell housed in the housing 1, that is, a battery that can be used alone, that is, a battery in which the battery element is sealed in a case and the positive and negative electrodes are provided on the outside. For example, a dry battery in which the battery element is sealed in a metal case, a battery in which the battery element is sealed in a plastic case, a laminated battery in which the battery element is sealed in a bag-shaped film such as a laminated material, or the like can be used. Furthermore, in the present invention, the battery housed in the housing 1 is not limited to a primary battery, and may be a secondary battery.

[0129] As shown in Figures 1B and 1C, in this embodiment, three single cells 2 are arranged side by side between the two electrode members 3a, 3b in the recess 11 of the lower skin sheet 10, with each electrode side of the cells 2 positioned on the right side.

[0130] Furthermore, battery snaps 21 with lead wires are attached to the electrodes of each cell 2, and the positive electrode lead wire 21a of the battery snap 21 of the cell 2 arranged on the most positive electrode side (right side) is connected and fixed by soldering to one end of the lead terminal 32 of the positive electrode side electrode member 3a, and the negative electrode lead wire 21b of the battery snap 21 of the cell 2 arranged on the most negative electrode side (left side) is connected and fixed by soldering to one end of the lead terminal 32 of the negative electrode side electrode member 3b. Furthermore, the positive electrode lead wire 21a and the negative electrode lead wire 21b of the battery snap 21 of adjacent cells 2 are connected. In this way, the multiple cells 2 are arranged so that the potential difference between the electrode members 3a, 3b is greatest.

[0131] After accommodating the cell 2 and the lower halves of the electrode members 3a, 3b in the recessed portions 11 of the lower skin sheet 10 in this manner, the upper skin sheet 10 is placed so as to accommodate the upper halves of the cell 2 and the electrode members 3a, 3b in the recessed portions 11, and the flange portions 12 of both skin sheets 10 are placed together. At this time, the other ends of the lead terminals 32 of the electrode members 3a, 3b on both sides are placed in correspondence with the openings 16 on both sides of the upper skin sheet 10. Here, in this embodiment, the other ends of the lead terminals 32 of the electrode members 3a, 3b are configured as external electrodes 4a, 4b.

[0132] With both skin sheets 10 thus arranged one on top of the other, the flange portions 12 of both skin sheets 10 are sandwiched between a pair of upper and lower heat seal dies and heated, thereby heat-sealing and joining the thermal adhesive layers 52 of both flange portions 12 together. Furthermore, the portions of the recessed portions 11 of both skin sheets 10 that correspond to the electrode members 3a and 3b are sandwiched between a pair of upper and lower heat seal dies and heated, thereby heat-sealing and joining the thermal adhesive layers 52 on the bottom surfaces (ceiling surfaces) of the recessed portions 11 of both skin sheets 10 and the upper and lower surfaces of the electrode members 3a and 3b together. In this way, the electricity storage module of this embodiment 1-1 is assembled.

[0133] In this embodiment, either a single-stage heat sealing process (single-stage sealing) in which the flange portion fusion process, which directly heat-welds both flange portions 12 together around the entire circumference, and the electrode member fusion process, which heat-welds the skin sheet 10 and the electrode members 3a, 3b, are performed simultaneously, or a two-stage heat sealing process (two-stage sealing) in which the two processes are performed separately can be used.

[0134] In this embodiment, the heating temperature (welding temperature) during the heat fusion treatment is preferably set to 140°C to 240°C, and more preferably 180°C to 210°C. Furthermore, the pressure during heat fusion (welding pressure) is preferably set to 0.05MPa to 0.5MPa, and more preferably 0.1MPa to 0.3MPa. Furthermore, the fusion time (welding time) is preferably set to 1 second to 10 seconds, and more preferably 2 seconds to 8 seconds.

[0135] In the electricity storage module of this embodiment fabricated as described above, the external electrodes 4a, 4b are connected to a power supply unit of an electric motor to supply electric power, thereby driving the electric motor.

[0136] According to the energy storage module of this embodiment configured as described above, the housing 1 is made of a skin sheet 10 made of laminate material L1, so that it is possible to reduce the weight and ensure sufficient electrical insulation compared to when a metal housing is used.

[0137] Furthermore, in the electricity storage module of this embodiment, the barrier layer 51 of the laminate material L1 that forms the skin sheet 10 is made of metal foil, and therefore heat conductivity can be ensured by the barrier layer 51. This improves heat dissipation and reliably prevents problems such as heat being trapped inside the housing 1 and adversely affecting the cells 2 and the like due to high heat.

[0138] Furthermore, in the energy storage module of this embodiment, the skin sheet 10 constituting the housing 1 is made of a laminate material L1 in which a resin thermal adhesive layer 52 and a protective layer 53 are laminated on both sides of a metal barrier layer 51, so that sufficient strength can be ensured. Compared to a case in which the housing is made of, for example, a thermal compression film, the strength of the housing 1 can be further improved, and defects such as breakage of the housing 1 can be reliably prevented, while also further improving durability.

[0139] Furthermore, in the electricity storage module of this embodiment, openings 16 that are cutout holes are formed in the skin sheet 10, and the external electrodes 4a, 4b are arranged in the openings 16. Electricity is supplied to and supplied from the cells 2 via the external electrodes 4a, 4b, so that even when high-voltage electricity is supplied to and supplied from the cells 2, adverse effects such as heat generation due to resistance do not affect the skin sheet 10, and it is possible to reliably prevent problems such as inadvertent exposure of the barrier layer 51 due to resin elution from the thermal adhesive layer 52. Therefore, unlike electricity storage modules (see FIGS. 1J to 1L) that use tab leads to supply and supply electricity, as will be described later, the electricity storage module of this embodiment can prevent problems such as a short circuit between the external electrodes 4a, 4b and the barrier layer (metal foil layer) 51 of the laminate material L1, and can further improve electrical insulation.

[0140] Furthermore, in the energy storage module of this embodiment, the peripheral portion of the opening 16 of the upper skin sheet 10 is heat-bonded to the outer surfaces of the electrode members 3a and 3b, thereby ensuring airtightness around the opening 16 of the skin sheet 10 and improving waterproofing, etc.

[0141] According to the energy storage module of this embodiment, multiple openings 16 are formed to form separate electrical outlets for the positive and negative electrodes, which more reliably prevents short circuits between the positive and negative electrodes and improves operational reliability.

[0142] <Embodiment 1-2> 1F to 1H are diagrams showing an electricity storage module according to Embodiment 1-2 of the present invention. As shown in these figures, the electricity storage module of this Embodiment 1-2 differs significantly from the electricity storage module of Embodiment 1-1 shown in Figures 1A to 1C in that, whereas the electricity storage module of Embodiment 1-1 uses rectangular 9V dry batteries as the cells 2 and the casing 1 is formed to correspond to the shape of the dry batteries, the electricity storage module of this Embodiment 1-2 uses circular (cylindrical) AA dry batteries as the cells 2 and the casing 1 is formed to correspond to the shape of the dry batteries.

[0143] That is, in this embodiment, the lower cover sheet 10 has a downward recess formed in the entire middle region except for the outer peripheral edge, forming a semi-cylindrical recess 11, with a flange 12 formed on the outer peripheral edge of the recess 11. The upper cover sheet 10 has an upward recess formed in the entire middle region except for the outer peripheral edge, forming a semi-cylindrical (semi-cylindrical) recess (bulge) 11, with a flange 12 formed on the outer peripheral edge. Furthermore, openings 16 are formed at both ends in the front-to-rear direction of the recess (bulge) 11 of the upper cover sheet 10.

[0144] The electrode members 3a, 3b include a cylindrical resin block member 31 corresponding to the cell 2, and a metal lead terminal 32 embedded in the block member 31. The lead terminal 32 has one end exposed at the center of one circular surface of the block member 31, an intermediate position bent upward by 90° within the block member 31, and the other end exposed at the upper end of the outer circumferential surface of the block member 31. In this embodiment 1-2, as in the above embodiment 1-1, the lead terminal 32 of the positive electrode member 3a is made of aluminum as shown in FIG. 1I(a), and the lead terminal 32 of the negative electrode member 3b is made of copper as shown in FIG. 1I(b).

[0145] As shown in FIGS. 1G and 1H, the positive electrode member 3a is accommodated on one side (right side) of the recess 11 of the lower skin sheet 10, and the negative electrode member 3b is accommodated on the other side (left side).

[0146] Furthermore, three single cells 2 are arranged in series between the two electrode members 3a, 3b in the recessed portion 11 of the lower skin sheet 10, with the positive electrode side of each cell 2 positioned on the right side.

[0147] In this battery storage state, the positive electrode (positive electrode) 2a of the cell 2 arranged on the most positive side (right side) is arranged in contact with one end of the lead terminal 32 of the positive electrode member 3a, and the negative electrode (negative electrode) 2b of the cell 2 arranged on the most negative side (left side) is arranged in contact with one end of the lead terminal 32 of the negative electrode member 3b. Furthermore, the positive electrodes 2a and negative electrodes 2b of adjacent cells 2 are arranged in contact with each other.

[0148] After accommodating the cell 2 and the lower halves of the electrode members 3a, 3b in the recessed portions 11 of the lower skin sheet 10 in this manner, the upper skin sheet 10 is placed so as to accommodate the cell 2 and the upper halves of the electrode members 3a, 3b in its recessed trunk portion 11, and the flange portions 12 of both skin sheets 10 are placed together. At this time, as in the above-described embodiment 1-1, the other ends (external electrodes) 4a, 4b of the lead terminals 32 of both electrode members 3a, 3b are placed in the openings 16 on both sides of the upper skin sheet 10.

[0149] Thereafter, similarly to the above-described embodiment 1-1, the thermal adhesive layers 52 of both flange portions 12 of both skin sheets 10 are thermally fused together to be integrated, and the thermal adhesive layers 52 on the bottom surfaces (ceiling surfaces) of the recessed portions 11 of both skin sheets 10 are thermally fused together with the outer peripheral surfaces of both electrode members 3a, 3b to be integrated, thereby assembling the electricity storage module of embodiment 1-2.

[0150] Other configurations of the energy storage module of this embodiment 1-2 are substantially the same as those of the energy storage module of embodiment 1-1, so the same or corresponding parts are denoted by the same reference numerals and redundant explanations will be omitted.

[0151] The power storage module of this embodiment 1-2 can also achieve the same effects as the power storage module of the above embodiment 1-1.

[0152] <Modification> In the above embodiment, an example was given in which two openings 16 are formed in the housing 1, but the number of openings is not limited in the present invention, and one opening or three or more openings may be provided.

[0153] Furthermore, in the above embodiment, an example was given in which three batteries such as single cells 2 are housed in the housing 1, but in the present invention, the number of batteries housed is not particularly limited as long as it is two or more.

[0154] In the above embodiment, the case where the housing 1 is formed using two skin sheets 10 has been described as an example, but this is not limited thereto. In the present invention, the housing may be formed by folding one skin sheet in half, or the housing may be formed using three or more skin sheets.

[0155] Furthermore, in the above embodiment, an example has been described in which a recessed skin sheet 10 (molded product) is used, but the present invention is not limited to this. Two flat, unmolded skin sheets (non-molded products) may be stacked on top of each other and thermally bonded at their outer edges to form a bag-like housing, or when forming a housing using a plurality of skin sheets, only some of the skin sheets may be molded products and the other skin sheets may be non-molded products to form the housing.

[0156] Needless to say, the shape of the opening 16 is not limited in the present invention. [Example]

[0157] <Example 1-1> As will be described below, in Example 1, an electricity storage module having a shape similar to that of the electricity storage module of Embodiment 1-1 shown in FIGS. 1A to 1C was fabricated.

[0158] (1) Preparation of the epidermal sheet 10 A 40 μm thick unstretched polypropylene (CPP) film was bonded to the inner surface of a 120 μm thick aluminum foil barrier layer 51 via a 40 μm thick urethane adhesive (3 μm thick) to form a thermal adhesive layer 52, and a 12 μm thick polyethylene terephthalate (PET) film was bonded to the other surface (outer surface) of the barrier layer 51 (aluminum foil) via a urethane adhesive (3 μm thick) to form a protective layer 53, thereby preparing a laminate material L1.

[0159] The laminate material L1 having a width of 100 mm and a length of 250 mm was deep-drawn to form a rectangular parallelepiped recess 11 having a width of 27 mm, a length of 150 mm and a depth of 9 mm, with the thermal adhesive layer 52 disposed on the inside, and the peripheral portion was cut to form a flange portion 12 having a width of 10 mm, thereby producing the lower skin sheet 10.

[0160] The laminate material L1 was similarly deep-drawn and cut to obtain the skin sheet 10. A circular opening 16 having a diameter of φ12 mm was formed in the bottom wall (upper wall) of the recessed portion (bulge) 11 by cutting out positions 10 mm from both ends, thereby producing the upper skin sheet 10.

[0161] (2) Preparation of electrode members 3a and 3b An L-shaped lead terminal 32 was formed by bending the center of an aluminum rod with a diameter of 3 mm and a length of 18 mm by 90 degrees. Using this lead terminal 32 as an insert member, an acid-modified polypropylene resin was injection molded to form a block member 31 with a width of 27 mm, a length of 15 mm, and a height of 18 mm, to produce a positive electrode member 3a (see FIG. 1E). In this electrode member 3a, the corner of the lead terminal 32 was positioned at the center of the block member 31, one end of the lead terminal 32 was exposed on one surface of the block member 32, and the other end of the lead terminal 32 was exposed on the upper surface of the block member 32.

[0162] A negative electrode member 3b was fabricated in the same manner as the positive electrode member 3a, except that a copper rod was used as the lead terminal 32.

[0163] (3) Preparing the battery As the cells 2, three rectangular 9V dry batteries were prepared (see Fig. 1B, Fig. 1C, etc.).

[0164] (4) Assembly of energy storage modules 1A to 1C, electrode members 3a, 3b were housed at both ends of the recessed portion of the lower skin sheet 10, and three single cells (9 V dry batteries) 2 connected in series with battery snaps 21 were housed therebetween. The positive electrode lead wire 21a of the most positive battery snap 21 was soldered to one end of the lead terminal 32 of the positive electrode member 3a, and the negative electrode lead wire 21b of the most negative battery snap 21 was soldered to one end of the lead terminal 32 of the negative electrode member 3b.

[0165] Next, the upper skin sheet 10 is placed so as to cover the cell 2 and electrode members 3a, 3b housed in the lower skin sheet 10, and the flange portion 12 of the upper skin sheet 10 is placed over the flange portion 12 of the lower skin sheet 10. In this way, a temporarily assembled (unbonded) electricity storage module is produced. In this temporarily assembled product, the other ends (external electrodes) 4a, 4b of the lead terminals 32 of both electrode members 3a, 3b are placed so as to face both openings 16 in the upper skin sheet 10.

[0166] Thereafter, the flange portions 12 of this temporary assembly were heat-sealed together (flange portion fusion treatment), and the contact portions of the skin sheet 10 and the electrode members 3a and 3b were heat-sealed together (electrode member fusion treatment) under the following sealing conditions, thereby producing the electricity storage module of Example 1-1.

[0167] The sealing conditions were a two-stage seal in which the first stage was a flange fusion process and the second stage was an electrode member fusion process. The first stage was performed under sealing conditions of 180°C x 0.3 MPa x 7 seconds, and the second stage was performed under sealing conditions of 190°C x 0.3 MPa x 7 seconds.

[0168] In both the first and second fusion treatments, a metal sealing mold without heat-conductive rubber was used.

[0169] <Example 1-2> In Example 1-2, an electricity storage module similar to the electricity storage module of Embodiment 1-2 shown in FIGS. 1F to 1I was fabricated.

[0170] A 40 μm thick unoriented polypropylene (CPP) film was bonded to the inner surface of a 120 μm thick aluminum foil barrier layer 51 via a 40 μm thick urethane adhesive (3 μm thick) to form a thermal adhesive layer 52, and a 25 μm thick biaxially oriented polyamide (ONY) film was bonded to the other surface (outer surface) of the barrier layer 51 (aluminum foil) via a urethane adhesive (3 μm thick) to form a protective layer 53, thereby preparing a laminate material L1.

[0171] The laminate material L1, 50 mm wide and 220 mm long, was deep-drawn to form a semi-cylindrical recess 11, 15 mm wide, 200 mm long, and 7.5 mm deep, with the thermal adhesive layer 52 disposed on the inside, and the peripheral edge was cut to form a flange 12, 10 mm wide, to produce the lower skin sheet 10. In the deep-drawing punch, the forming portion for forming the recess 11 was set to 7.5R (radius 7.5 mm).

[0172] The laminate material L1 was similarly deep-drawn and cut to obtain the skin sheet 10. A rectangular opening 16 measuring 10 mm in the circumferential direction and 8 mm in width was formed by cutting out a portion 7.5 mm from both ends of the bottom wall (top wall) of the recess (bulge) 11, thereby producing the upper skin sheet 10.

[0173] An L-shaped lead terminal 32 was formed by bending the center of an aluminum rod having a diameter of 3 mm and a length of 18 mm by 90 degrees. Using this lead terminal 32 as an insert member, an acid-modified polypropylene resin was injection molded to form a block member 31 having a diameter of 15 mm and a thickness of 15 mm, thereby producing a positive electrode member 3a (see FIG. 1I). In this electrode member 3a, the corner of the lead terminal 32 was located at the center of the block member 31, one end of the lead terminal 32 was exposed on one surface of the block member 32 in the thickness direction, and the other end of the lead terminal 32 was exposed on the peripheral surface (top surface) of the block member 32.

[0174] A negative electrode member 3b was fabricated in the same manner as the positive electrode member 3a, except that a copper rod was used as the lead terminal 32.

[0175] As in embodiment 1-2 of FIGS. 1G and 1H, electrode members 3a, 3b are housed at both ends of the recessed portion of the lower skin sheet 10, and three unit cells (AA alkaline batteries) 2 are housed in series therebetween, with the positive electrode 2a of the most positive unit cell 2 being in contact with one end of the lead terminal 32 of the positive electrode member 3a, and the negative electrode 2b of the most negative unit cell 2 being in contact with one end of the lead terminal 32 of the negative electrode member 3b.

[0176] Next, the upper skin sheet 10 is placed so as to cover the cell 2 and electrode members 3a, 3b housed in the lower skin sheet 10, and the flange portion 12 of the upper skin sheet 10 is placed over the flange portion 12 of the lower skin sheet 10. In this way, a temporarily assembled (unbonded) electricity storage module is produced. In this temporarily assembled product, the other ends (external electrodes) 4a, 4b of the lead terminals 32 of both electrode members 3a, 3b are placed so as to face both openings 16 in the upper skin sheet 10.

[0177] Thereafter, this temporary assembly was subjected to a flange fusion process and an electrode member fusion process under the same sealing conditions as in Example 1-1 above, to produce an electricity storage module of Example 1-2.

[0178] <Comparative Example 1-1> 1J to 1L, a conventional tab-lead type electricity storage module (see Patent Document 1: Japanese Patent No. 5459398, etc.) was fabricated as Comparative Example 1-1. In this Comparative Example 1-1, the lower skin sheet 10 has the same configuration as in Example 1-1, and the upper skin sheet 10 has the same configuration as in Example 1-1, except that no openings 16 are formed.

[0179] In Comparative Example 1-1, the electrode members 3a and 3b were not used, and a positive electrode tab lead 8a and a negative electrode tab lead 8b were used.

[0180] The tab leads 8a and 8b each include a strip-shaped tab lead body 81 and a covering film 82 bonded via an adhesive to both sides of the central portion of the tab lead body 81 (the portion corresponding to the flange portion 12 when fused).

[0181] In the positive electrode tab lead 8a, the tab lead body 81 is made of an aluminum plate with a thickness of 0.2 mm, a width of 10 mm, and a length of 30 mm. The covering film 82 is made of maleic anhydride-modified polypropylene ("Modic P502" manufactured by Mitsubishi Chemical Corporation) and is made of a film with a thickness of 0.1 mm, a width of 14 mm, and a length of 15 mm.

[0182] The negative electrode tab lead 8b is made of a nickel plate having a thickness of 0.2 mm, a width of 10 mm and a length of 30 mm. The covering film 82 is the same as the covering film 82 of the positive electrode tab lead 8a.

[0183] The covering films 82 of the positive electrode tab lead 8a and the negative electrode tab lead 8b are placed on the flange portions 12 on the positive electrode side (right side) and negative electrode side (left side) of the lower skin sheet 10, with one end side (inner end side) of the tab leads 8a and 8b being placed inside the recessed portion 11 and the other end side (outer end side) being placed outside.

[0184] Furthermore, similar to Example 1-1 above, three rectangular 9V dry batteries (single cells) 2 connected in series via battery snaps 21 are placed in the recessed portion 11 of the lower skin sheet 10, with the positive electrode lead wire 21a of the battery snap 21 of the most positive cell 2 soldered to the inner end of the positive electrode tab lead 8a, and the negative electrode lead wire 21b of the battery snap 21 of the most negative cell 2 soldered to the inner end of the negative electrode tab lead 8b.

[0185] Thereafter, the upper skin sheet 10 was placed over the lower skin sheet 10, and the flange portions 12 were arranged so as to overlap each other, and fused with a two-stage seal in the same manner as in Example 1-1 above to produce the storage module of Comparative Example 1-1.

[0186] In the first stage of fusion processing, the flange portions 12 of the upper and lower skin sheets 10 were heat-fused together, and in the second stage of fusion processing, the flange portions 12 of the skin sheets 10 were heat-fused to the covering films 82 of the tab leads 8a and 8b.

[0187] <Evaluation of formability>

[0188] [Table 1]

[0189] In Example 1-1, after deep-drawing the skin sheet 10, the skin sheet 10 was left to stand for 1 minute and the maximum depth of the recessed portion was measured with a vernier caliper. As a result, the maximum depth was 8.9 mm to 9.0 mm (deformation amount 0.1 mm or less) compared to the target depth of 9 mm. If the depth is 0.3 mm or less compared to the target value of the mold forming depth, it is acceptable, and therefore the formability is evaluated as "good". The results are also shown in Table 1.

[0190] In Example 1-2, after deep drawing the skin sheet, the maximum depth of the recessed portion was measured in the same manner as above. As a result, the maximum depth was 7.4 mm to 7.5 mm (deformation amount 0.1 mm or less) compared to the target of 7.5 mm, and the formability was evaluated as acceptable (○). The results are also shown in Table 1.

[0191] <Evaluation of continuity (voltage)> In the energy storage modules of Examples 1-1 and 1-2, the potential difference between the positive and negative external electrodes 4a, 4b was measured with a tester. The results are also shown in Table 1.

[0192] In the electricity storage module of Comparative Example 1.1, the potential difference between the positive and negative electrode tab leads 8a, 8b was measured with a tester. The results are also shown in Table 1.

[0193] <Evaluation of internal pressure resistance> A syringe needle with a diameter of 1 mm inserted through a 1 mm thick, 10 mm diameter silicone rubber was inserted into the energy storage modules of Example 1-1, Example 1-2, and Comparative Example 1-1. Air was then injected through the needle to apply a pressure (air pressure) of 0.2 MPa to the energy storage modules for one minute, and the amount of deformation of each energy storage module was measured. The amount of deformation was measured as the difference between the state of the energy storage module before pressure was applied and the maximum amount of deformation while pressure was applied. A deformation (expansion) of 0.1 mm or less was evaluated as excellent (◎), a deformation of more than 0.1 mm but not more than 0.3 mm was evaluated as good (○), a deformation of more than 0.3 mm but not more than 0.6 mm was evaluated as fair (△), and a deformation of more than 0.6 mm was evaluated as poor (×). The evaluation results are also shown in Table 1.

[0194] <External pressure resistance evaluation> The energy storage modules of Example 1-1, Example 1-2, and Comparative Example 1-1 were placed on a concrete base, and an aluminum plate measuring 10 mm thick, 800 mm long, and 100 mm wide was placed on top of them. A pressure of 5 MPa was applied for 5 minutes, and then each energy storage module was removed and observed for deformation. Since no deformation was observed in the areas where the electrode members 3a and 3b and the single cells 2 were present, the deformation of the hollow areas where these were not present was observed. Those without deformation were evaluated as good (○), and those with deformation were evaluated as poor (×). The evaluation results are also shown in Table 1.

[0195] As is clear from Table 1, the energy storage modules of Examples 1-1 and 1-2 have excellent moldability and are superior in resistance to internal pressure and resistance to external pressure compared to the energy storage module of Comparative Example 1-1.

[0196] <Embodiment 2> 2A to 2C are diagrams showing an energy storage module according to a second embodiment of the present invention. In the following description, to facilitate understanding of the invention, the left-right direction in Fig. 2B will be referred to as the "front-rear direction (length direction)", the up-down direction in Fig. 2B will be referred to as the "up-down direction (thickness direction)", and the direction perpendicular to the plane of Fig. 2B will be referred to as the "width direction (left-right direction)".

[0197] As shown in Figures 2A to 2C, the energy storage module of this embodiment has, as its basic components, a housing (energy storage module housing) 1 as a casing (container), a battery cell 2 housed in the housing 1, and tab leads 8a, 8b for inputting and outputting electricity to and from the battery cell 2.

[0198] The housing 1 is composed of two skin sheets 10, one above the other. The skin sheets 10 are made of a laminate material L1, which will be described later, and are formed using techniques such as deep drawing and extrusion molding. The upper skin sheet 10 has a shape that is upside down compared to the lower skin sheet 10, and both skin sheets 10 have substantially the same shape.

[0199] In this embodiment, the lower skin sheet 10 has a downward recess formed over the entire middle region except for the outer peripheral edge, forming a rectangular parallelepiped recess 11, and an outwardly protruding flange 12 is integrally formed on the outer periphery of the opening edge of the recess 11.

[0200] As already mentioned, the upper skin sheet 10 has a shape obtained by inverting the lower skin sheet 10 upside down, and has a rectangular parallelepiped-shaped recessed portion 11 formed to bulge upward, and a flange portion 12 integrally formed on the outer peripheral edge of the recessed portion (bulging portion) 11 so as to protrude outward.

[0201] The surface sheet 10 is made of a laminate material L1 which is a laminate sheet or film having flexibility and pliability.

[0202] 2D, the laminate material L1 includes a barrier layer 51 made of metal (metal foil), a heat-sealable thermal adhesive layer 52 laminated via an adhesive on one surface (inner surface) of the barrier layer 51, and a heat-resistant protective layer 53 laminated via an adhesive on the other surface (outer surface) of the barrier layer 51. In this embodiment, the term "foil" is used to include a film, a sheet, and a thin plate.

[0203] Aluminum (aluminum foil) is used as the metal constituting the barrier layer 51. In this embodiment, "aluminum" includes aluminum alloys.

[0204] In this embodiment, the aluminum constituting the barrier layer 51 must be aluminum (aluminum foil) selected from 1000 series, 3000 series, 5000 series, and 8000 series, and it is particularly preferable to use 8000 series aluminum.

[0205] Specifically, the aluminum constituting the barrier layer 51 is preferably aluminum (aluminum foil) selected from pure aluminum with a purity of 99.0% (mass %, the same applies hereinafter) or higher, an Al-Mn-based aluminum alloy containing 1.0% to 1.5% Mn, 0.05% to 0.2% Cu or 0.8% to 1.3% Mg, with the balance being Al and unavoidable impurities, and an Al-Fe-based aluminum alloy containing 1.2% to 1.7% Fe (mass %, the same applies hereinafter) or 0.7% to 1.3% Fe and 0.05% to 0.3% Si, with the balance being Al and unavoidable impurities, and Al-Fe-based aluminum is particularly preferably used.

[0206] That is, this aluminum has superior formability compared to other types of aluminum, and good formability can be obtained, allowing the skin sheet 10 to be reliably formed into a desired shape.

[0207] In this embodiment, the aluminum foil of the barrier layer 51 has an elongation of 15% to 35% (including a lower limit of 15% and an upper limit of 35%, the same applies hereinafter) measured in accordance with JIS H 4000 (2014), a Vickers hardness (Vickers hardness) of 20 to 60 measured in accordance with JIS Z 2244 (2009), and a longitudinal elastic modulus of 60 kN / mm 2 measured in accordance with JIS Z 2280 (1993). 2 ~80kN / mm 2 By adjusting the mechanical properties (physical properties) of the barrier layer 51 to these values, it is possible to form a molded product (housing 1) that is lightweight, has excellent moldability, and has excellent shape retention (strength) after molding, and is therefore resistant to deformation even when subjected to external impact or vibration. Therefore, as will be described later, it is possible to effectively prevent short circuits from occurring due to deformation or misalignment of the cells 2 housed in the housing 1 and the internal lead wires 21 a, 21 b.

[0208] Since resin layers (thermal adhesive layer 52 and protective layer 52) are provided on both sides of barrier layer 51, sufficient insulation can be ensured.

[0209] The thickness of the barrier layer 51 is preferably set to 40 μm to 200 μm, and more preferably to 60 μm to 160 μm. In other words, when the thickness of the barrier layer 51 is set to the above-mentioned specific thickness, it is possible to improve moldability while ensuring sufficient shape stability (strength) and barrier properties after molding. In other words, if the thickness of the barrier layer 51 is too thin, there is a risk that the desired barrier properties and shape stability cannot be obtained after molding, and conversely, if the thickness of the barrier layer 51 is too thick, there is a risk that flexibility will decrease and moldability will deteriorate.

[0210] It is preferable to use aluminum with an O temper as the aluminum for the barrier layer 51. That is, in this embodiment, although H18 material can also be used as the aluminum for the barrier layer 51, O material is more preferable because it is easier to form and can further improve formability.

[0211] It is preferable to provide an underlayer on one or both sides of the barrier layer 51. The underlayer is preferably a chemical conversion coating formed by chromate treatment, silicate treatment, zirconium-based chemical conversion treatment, or the like.

[0212] The amount of the undercoat layer varies depending on the treatment method. For example, the amount of chromium applied to one side of a metal foil during chemical conversion treatment is 0.1 mg / m. 2 ~50mg / m 2 It is recommended to set it at 2 mg / m 2 ~20mg / m 2 It is better to set it to .

[0213] When a base layer is formed on the barrier layer 51 in this manner, the resin layers such as the thermal adhesive layer 52 and the protective layer 53 laminated on the barrier layer 51 are less likely to peel off, preventing delamination. This reliably prevents exposure of the metallic barrier layer 51, improves the barrier properties, and effectively prevents corrosion of the barrier layer 51.

[0214] The thermal adhesive layer 52 is preferably made of a thermoplastic non-stretched resin, such as a film or coating layer of non-stretched resin such as non-oriented polypropylene (CPP), polyethylene (LDPE, LLDPE, HDPE, etc.), acid-modified polyolefin resin, ionomer resin, EMAA (ethylene-methacrylic acid copolymer resin), etc.

[0215] The thickness of the thermal adhesive layer 52 is preferably set to 5 μm to 150 μm, and more preferably set to 30 μm to 100 μm.

[0216] When the above-mentioned specific resin and thickness are used for the thermal adhesive layer 52, good thermal adhesion can be ensured, and the upper and lower skin sheets 10 can be firmly thermally fused together and fixed between the skin sheets 10 and the cells 2, so that the cells 2 can be securely fixed within the skin sheets 10, i.e., within the housing 1, and misalignment of the cells 2 and the lead wires 21a, 21b (described below) connected to the cells 2 can be reliably prevented, thereby reliably preventing the occurrence of defects such as short circuits. Furthermore, the thermal adhesive layer 52 is less likely to flow out during thermal fusion, preventing exposure of the metallic barrier layer 51 and improving insulation and corrosion resistance.

[0217] The protective layer 53 is preferably formed by adhering a biaxially oriented film, such as a biaxially oriented polyester film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate (PBT), a biaxially oriented polyamide (ONY) film such as PA6 or PA66, or a biaxially oriented polypropylene (OPP) film.

[0218] The thickness of protective layer 53 is preferably set to 5 μm to 100 μm, and more preferably 9 μm to 50 μm. When the above-mentioned specific resin and thickness are used for protective layer 53, sufficient strength can be obtained as protective layer 53, puncture resistance can be improved, exposure of metallic barrier layer 51 can be prevented, and electrical insulation and corrosion resistance can be further improved.

[0219] Furthermore, it is preferable to use a material for the protective layer 53 that has a melting point higher than that of the resin constituting the thermal adhesive layer 52, preferably a melting point 10° C. or higher. In other words, when a material with a high melting point is used for the protective layer 53, adverse effects of heat on the protective layer 53 can be avoided when the thermal adhesive layer 52 is thermally fused (thermally bonded) by heating.

[0220] The laminate material L1 having the above configuration is used as the sheet material for the upper and lower skin sheets, and the sheet material is recessed and cut to form the skin sheets 10. As will be described later, the flange portions 12 of the upper and lower skin sheets 10 are thermally fused (thermally adhered) to each other to form the energy storage module housing 1. In this housing 1, the recessed portions 11 of the upper and lower skin sheets 10 form a rectangular parallelepiped battery housing portion 15.

[0221] 2B and 2C, the cell 2 used in this embodiment is a commercially available prismatic 9V dry cell battery. Needless to say, this cell 2 has a prismatic shape with a positive electrode and a negative electrode arranged side by side on one side.

[0222] In the present invention, the unit cells housed in the housing 1 can be any type of battery that can be used alone, i.e., a battery in which the battery elements are enclosed in a case and electrodes such as a positive and negative electrodes are provided externally. For example, batteries that can be used include the above-mentioned prismatic dry batteries and cylindrical dry batteries in which the battery elements are enclosed in a metal case, batteries in which the battery elements are enclosed in a plastic case, and laminated batteries (laminated batteries) in which the battery elements are enclosed in a bag-shaped film such as a laminated material. Furthermore, in the present invention, the batteries housed in the housing 1 are not limited to primary batteries, and can also be secondary batteries.

[0223] Tab leads 8a and 8b are used as electrodes. The tab leads 8a and 8b each include a strip-shaped tab lead body 81 and a covering film 82 provided on both sides of the center of the tab lead body 81. The covering film 82 is provided in correspondence with the flange portion 12 of the skin sheet 10, and is fixed to the flange portion 12 by heat fusion as described below.

[0224] As shown in FIGS. 2B and 2C, in this embodiment, three cells 2 are arranged side by side in the recessed portion 11 of the lower skin sheet 10 with their electrode sides positioned on the right side.

[0225] Each cell 2 has a battery snap 21 with a lead wire attached to its electrode, with the positive electrode tab lead 8a positioned on the positive electrode end (right end) of the flange portion 12 of the skin sheet 10 and the negative electrode tab lead 8b positioned on the negative electrode end (left end). The positive electrode lead wire 21a of the battery snap 21 of the cell 2 located closest to the positive electrode (right side) is connected and fixed by soldering to the base end (inner end) of the positive electrode tab lead 8a, with the tip (outer end) of the positive electrode tab lead 8a extending outward from the positive electrode side. The negative electrode lead wire 21b of the battery snap 21 of the cell 2 located closest to the negative electrode (left side) is connected and fixed by soldering to the base end (inner end) of the negative electrode tab lead 8b, with the tip (outer end) of the negative electrode tab lead 8b extending outward from the negative electrode side. This positions the cells 2 so that the potential difference between the tab leads 8a and 8b is greatest.

[0226] In this way, the lower half of the cell 2 is accommodated in the recess 11 of the lower skin sheet 10, and the tab leads 8a, 8b are arranged with their covering films 82 on the flanges 12. Then, the upper skin sheet 10 is accommodated in its recess 11 with the upper half of the cell 2, and the flanges 12 are placed over the covering films 82 of the tab leads 8a, 8b, with the flanges 12 of both skin sheets 10 overlapping each other.

[0227] In this state, the flanges 12 of the skin sheets 10 are sandwiched between a pair of upper and lower heat seal dies and heated, whereby the thermal adhesive layers 52 of the flanges 12 are heat-sealed and joined together, and the flanges 12 of the skin sheets 10 are heat-sealed and joined together with the covering films 82 of the tab leads 8a, 8b. In this way, the upper and lower skin sheets 10 enclose the cells 2, and the electricity storage module is assembled.

[0228] In this embodiment, the inner surface of the recessed portion 11 of the skin sheet 10 constituting the housing 1 is fixed to the outer surface of the cell 2. Examples of the fixing means include a means using a fixing tape, a means using heat fusion (thermal adhesion), and a means using an adhesive.

[0229] As a means for using tape, double-sided tape such as adhesive tape can be used. For example, the outer circumferential surface of the cell 2 can be fixed to the inner circumferential surface of the housing 1 by using double-sided adhesive tape in which a silicon-based adhesive, an acrylic-based adhesive, or a rubber-based adhesive is applied to both sides of a film substrate (polyethylene terephthalate).

[0230] As a means of using heat fusion, if a heat-bondable resin is laminated in advance as an inner layer of the skin sheet 10 to the material used for the outer layer of the unit cell 2, the outer surface of the unit cell 2 can be fixed to the inner surface of the housing 1 by heating and pressurizing the part of the skin sheet 10 corresponding to the unit cell 2.

[0231] For reference, if the cell is a cylindrical or prismatic dry cell, the outermost layer is covered with an insulating, heat-shrinkable resin tube (made of polyolefin, vinyl chloride, etc.). Furthermore, if the cell is a laminated battery, the outermost layer is sealed with a polyethylene terephthalate (PET) film or a biaxially oriented polyamide (ONY) film. Therefore, for a cylindrical dry cell whose outermost layer is a polyolefin tube, a CPP film, LDPE film, or LLDPE film can be used for the inner layer of the skin sheet 10. Furthermore, for a prismatic dry cell whose outermost layer is a vinyl chloride tube, an acid-modified polypropylene (acid-modified PP) film or an acid-modified polyethylene (acid-modified PE) film can be used for the inner layer of the skin sheet 10. Furthermore, for a laminated battery whose outermost layer is a polyethylene terephthalate (PET) film or a biaxially oriented polyamide (ONY) film, an acid-modified polypropylene film can be used for the inner layer of the skin sheet 10.

[0232] As a means for using an adhesive, a heat-bondable adhesive may be applied to the outer layer of the cells 2 in advance, followed by drying to form an adhesive layer, and then the outer peripheral surface of the cells 2 can be fixed to the inner peripheral surface of the housing 1 by heating and pressurizing the portions of the skin sheet 10 corresponding to the cells 2. An example of such an adhesive is an acid-modified polypropylene adhesive that uses blocked isocyanate as a curing agent.

[0233] When thermally bonding the outer surface of the cell 2 to the inner surface of the skin sheet 10, a one-stage seal (one-stage seal method) may be used in which the thermal bonding process between the skin sheet 10 and the cell 2 and the thermal bonding (sealing) process between the skin sheets 10 are performed simultaneously, as described above, or a two-stage seal (two-stage seal method) in which these processes are performed separately may be used.

[0234] In the electricity storage module of this embodiment thus fabricated, the tab leads 8a and 8b are connected to a power supply section of the electric motor to supply electric power, thereby driving the electric motor.

[0235] According to the energy storage module of this embodiment having the above-described configuration, the housing 1 is made of a skin sheet 10 made of laminate material L1, so that the weight can be reduced compared to when a metal housing is used, and sufficient electrical insulation can be ensured.

[0236] Furthermore, in the electricity storage module of this embodiment, the barrier layer 51 of the laminate material L1 that constitutes the skin sheet 10 is made of a specific aluminum foil, which enables the skin sheet 10 to be made lighter while improving its formability and shape retention (strength) after molding. Therefore, the casing 10 formed from the skin sheet 10 has sufficient impact resistance and vibration resistance, and is able to prevent harmful deformation or damage even when subjected to external impact or vibration. It is also able to reliably prevent short circuits due to deformation or misalignment of the cells 2, battery snaps 21, and their lead wires 21a, 21b housed within the casing 1, further improving durability, resulting in a high-quality electricity storage module.

[0237] In addition, in this embodiment, the barrier layer 51 of the skin sheet 10 is made of aluminum foil, and therefore heat conductivity can be ensured by the barrier layer 51. This improves heat dissipation and reliably prevents problems such as heat buildup inside the housing 1 and adverse effects of high heat on the cells 2, etc.

[0238] In the above embodiment, an example has been described in which three cells 2 are housed in the housing 1, but in the present invention, the number of cells housed is not particularly limited as long as it is two or more.

[0239] In the above embodiment, the case where the housing 1 is formed using two skin sheets 10 has been described as an example, but this is not limited thereto. In the present invention, the housing may be formed by folding one skin sheet in half, or the housing may be formed using three or more skin sheets.

[0240] In the above embodiment, the case where a recessed skin sheet 10 (molded product) is used has been described as an example, but the present invention is not limited to this, and a bag-shaped housing may also be formed by overlapping two unmolded, flat skin sheets (non-molded products) and thermally bonding their outer peripheries. Furthermore, when forming a housing using multiple skin sheets, the housing may be formed by using only some skin sheets as molded products and the other skin sheets as non-molded products. [Example]

[0241] [Table 2]

[0242] <Example 2-1> As will be described below, in the examples and comparative examples, energy storage modules having the same shape as the energy storage module of the second embodiment shown in FIGS. 2A to 2C were fabricated.

[0243] (1) Preparation of the epidermal sheet 10 As shown in Table 2, a 40 μm thick unstretched polypropylene (CPP) film was bonded to the inner surface of an aluminum foil barrier layer 51 (thickness 120 μm) made of O material with alloy number A8021H, via a 40 μm thick urethane adhesive (thickness 3 μm), to form a thermal adhesive layer 52, and a 12 μm thick polyethylene terephthalate (PET) film was bonded to the other side (outer surface) of the barrier layer 51 (aluminum foil) via a urethane adhesive (thickness 3 μm), to form a protective layer 53, thereby preparing a laminate material L1.

[0244] The aluminum foil as the barrier layer 51 has an elongation of 30% measured in accordance with JIS H 4000 (2014), a Vickers hardness of 29 measured in accordance with JIS Z 2244 (2009), and a longitudinal elastic modulus of 69 kN / mm 3 measured in accordance with JIS Z 2280 (1993). 2 is.

[0245] The laminate material L1 was cut to a size of 100 mm in width and 250 mm in length, and the cut laminate material L1 was deep-drawn to form a rectangular parallelepiped recess 11 having a width of 27 mm, a length of 150 mm and a depth of 9 mm, with the thermal adhesive layer 52 disposed on the inside. The peripheral edge was cut to form a flange 12 having a width of 10 mm, thereby producing the lower skin sheet 10.

[0246] The laminate material L1 was similarly deep-drawn and cut to form the upper skin sheet 10.

[0247] (2) Fabrication of tab leads 8a and 8b Tab leads 8a and 8b were prepared by bonding cover films 82 to both sides of the center of a tab lead body 81.

[0248] In this case, the tab lead body 81 of the positive electrode tab lead 8a was made of an aluminum plate having a thickness of 0.2 mm, a width of 10 mm, and a length of 30 mm, and the covering film 82 was made of a film having a thickness of 0.1 mm, a width of 14 mm, and a length of 15 mm, made from maleic anhydride-modified polypropylene ("Modic P502" manufactured by Mitsubishi Chemical Corporation).

[0249] The tab lead body 81 of the negative electrode tab lead 8b was made of a nickel plate having a thickness of 0.2 mm, a width of 10 mm and a length of 30 mm, and the covering film 82 was made of the same material as the covering film 82 of the positive electrode tab lead 8a.

[0250] (3) Preparing the battery Three rectangular 9V dry batteries were prepared as the cells 2 (see Figures 2B, 2C, etc.). Double-sided adhesive tape (15mm wide x 30mm long x 0.8mm thick) manufactured by 3M (3M Japan) was attached to the top and bottom surfaces of each cell 2 to secure the cells 2 to the housing 1.

[0251] (4) Assembly of energy storage modules As in embodiment 2 in FIGS. 2A to 2B, three cells (9 V dry batteries) 2 connected in series with battery snaps 21 were housed in the recess 11 of the lower skin sheet 10, with the positive electrode lead wire 21a of the most positive battery snap 21 soldered to the base end (inner end) of the positive electrode tab lead 8a, and the negative electrode lead wire 21b of the most negative battery snap 21 soldered to the base end (inner end) of the negative electrode tab lead 8b.

[0252] Next, the upper skin sheet 10 is placed so as to cover the cell 2 housed in the lower skin sheet 10, and the flange portion 12 of the upper skin sheet 10 is placed over the flange portion 12 of the lower skin sheet 10. At this time, the covering films 82 of the tab leads 8a, 8b are sandwiched between the flange portions 12 of the upper and lower skin sheets 10, and the tips (outer ends) of the tab leads 8a, 8b are placed so as to extend to the outside. In this manner, a storage module in a temporary assembled state (unbonded state) was produced. In this temporary assembly, the double-sided adhesive tape attached to the upper and lower surfaces of the cell 2 is positioned so as to be adhered to the inner surfaces of the recessed portions of the upper and lower skin sheets 10.

[0253] Next, this temporary assembly was subjected to a thermal bonding process using a two-stage sealing method. In the first stage, sealing dies were used from above and below to sandwich and heat both flanges 12 at the outer peripheries of the upper and lower skin sheets 10, thereby heat-sealing the flanges 12 together and also heat-sealing the flanges 12 and the covering films 82 of the tab leads 8a and 8b, thereby sealing the cell 2 with the skin sheets 10 (housing 1).

[0254] In the second sealing step, the bottom wall (upper wall) of the recess 11 of the skin sheet 10 was pressed from above and below with a sealing mold and pressed against both sides of the cell 2, and then heated to thermally bond the inner surface of the recess of the skin sheet 10 to the outer surface of the cell 2. In this way, the electricity storage module of Example 2-1 was produced.

[0255] The first sealing conditions were 190°C x 0.3 MPa x 7 seconds, and the second sealing conditions were 60°C x 0.3 MPa x 7 seconds.

[0256] The first and second sealing molds were made of metal and had no heat-conductive rubber attached.

[0257] <Example 2-2> As shown in Table 2, the laminate material L1 is an aluminum foil having a thickness of 80 μm and a barrier layer 51 made of an O material of alloy number A3003H (elongation 18%, Vickers hardness 28, modulus of longitudinal elasticity 70 kN / mm2 An electricity storage module of Example 2-2 was produced in the same manner as in Example 2-1, except that the above-mentioned cellulose acylate 1 was used.

[0258] <Example 2-3> As shown in Table 2, the laminate material L1 is a 50 μm thick aluminum foil (elongation 18%, Vickers hardness 24, modulus of longitudinal elasticity 69 kN / mm) with a barrier layer 51 made of an O material of alloy number A8079H. 2 An electricity storage module of Example 2-3 was produced in the same manner as in Example 2-1, except that protective layer 53 was an ON film having a thickness of 25 μm.

[0259] <Comparative Example 2-1> As shown in Table 2, the barrier layer 51 is an aluminum foil (elongation 15%, Vickers hardness 16, modulus of longitudinal elasticity 69 kN / mm) with a thickness of 50 μm, which is made of an O material of alloy number A1N30H. 2 ) was used, and the protective layer 53 was an ON film having a thickness of 25 μm. Except for this, the same laminate material L1 as in Example 2-1 was prepared, and the surface sheet 10 was produced using this laminate material L1 in the same manner as in Example 2-1.

[0260] Next, a temporary assembly was prepared in the same manner as in Example 2-1 above, except that no double-sided adhesive tape was attached to each of the cells 2 .

[0261] This temporary assembly was subjected to a thermal bonding process using a one-stage sealing method. That is, both flange portions 12 at the outer periphery were heat-sealed from above and below using a sealing mold, and the flange portions 12 and the covering films 82 of the tab leads 8a and 8b were also heat-sealed to seal the cells 2 with the skin sheet 10 (housing 1), thereby producing the energy storage module of Comparative Example 2-1. The sealing conditions at this time were the same as those for the first stage of Example 2-1.

[0262] In the electricity storage module of Comparative Example 2-1, the cells 2 and the housing 1 are not fixed to each other and are in a detachable state.

[0263] <Comparative Example 2-2> As shown in Table 2, the barrier layer 51 is an aluminum foil (elongation 1.5%, Vickers hardness 55, modulus of longitudinal elasticity 70 kN / mm) with a thickness of 80 μm, made of H18 material of alloy number A3003H. 2 A laminate material L1 identical to that of Example 2-1 was prepared, except that the laminate material L1 was used. When this laminate material L1 was cut and molded in the same manner as in Example 2-1, the moldability (see "Evaluation of moldability" below) was poor, and the desired molded product could not be obtained, so the subsequent work was discontinued.

[0264] <Evaluation of formability> Each of the laminate materials of the Examples and Comparative Examples was cut and deep-drawn in the same manner as above to obtain test articles (deep-drawn articles) of the Examples and Comparative Examples.

[0265] The moldability of each test piece was evaluated by checking for the presence or absence of molding cracks, pinholes, etc. using the light transmission method in a dark room. As a result, those without molding cracks or pinholes were rated as good (○), and those with at least one of molding cracks and pinholes were rated as poor (×). The results are also shown in Table 2.

[0266] <Evaluation of shape stability> In the examples and comparative examples, the skin sheet 10 was deep-drawn, allowed to stand for one minute, and the maximum depth of the central recess was measured with a vernier caliper. Shape stability was evaluated based on the amount of deformation of the maximum depth of the central recess in each molded product. The evaluation criteria were as follows: a maximum depth of 9 mm to 9.1 mm (deformation of 0.1 mm or less) was rated as excellent (◎); a maximum depth of more than 9.1 mm but 9.5 mm (deformation of more than 0.1 mm but 0.5 mm or less) was rated as good (○); a maximum depth of more than 9.5 mm but 10 mm (deformation of more than 0.5 mm but 1.0 mm or less) was rated as fair (△); and a maximum depth of more than 10 mm (deformation of more than 1.0 mm) was rated as poor (×). The results are also shown in Table 2.

[0267] <Evaluation of conductivity> In each of the energy storage modules of the example and comparative examples, the voltage between positive electrode tab lead 8a and negative electrode tab lead 8b was measured with a tester. The results are also shown in Table 2.

[0268] <Evaluation of internal pressure resistance> A syringe needle with a diameter of 1 mm inserted through a 1 mm thick x 10 mm diameter silicone rubber was inserted into each energy storage module of the example and comparative examples. Air was injected through the needle to apply a pressure (air pressure) of 0.2 MPa to the energy storage module for 1 minute, and the deformation of each energy storage module was measured. The deformation was measured as the difference between the state of the energy storage module before and after the pressure was applied (maximum deformation). Deformation (expansion) of 0.1 mm or less was evaluated as excellent (◎), 0.1 mm or more but not exceeding 0.3 mm was evaluated as good (○), 0.3 mm or more but not exceeding 0.6 mm was evaluated as fair (△), and 0.6 mm or more was evaluated as poor (×). The evaluation results are also shown in Table 2.

[0269] <Evaluation of external pressure resistance> The energy storage modules of the example and comparative examples were placed on a concrete base, and an aluminum plate measuring 10 mm thick, 200 mm long, and 60 mm wide was placed on top of it. A pressure of 0.5 MPa was applied for 5 minutes, and then each energy storage module was removed and observed for deformation. Since no deformation was observed in the area where the cells 2 were present, the deformation of the cavity where they were not present (the gap between adjacent dry cells) was observed. Those without deformation were evaluated as good (○), and those with deformation were evaluated as poor (×). The evaluation results are also shown in Table 2.

[0270] As is clear from Table 2, the electricity storage modules of Examples 2-1 to 2-3 have excellent moldability and shape stability, and are superior in resistance to internal pressure and resistance to external pressure compared to the electricity storage module of the comparative example.

[0271] <Embodiment 3> 3A to 3C are diagrams showing an electricity storage module according to a third embodiment of the present invention. In the following description, to facilitate understanding of the invention, the up-down direction in Fig. 3B will be referred to as the "up-down direction (thickness direction)".

[0272] As shown in Figures 3A to 3C, the energy storage module of this embodiment has, as basic components, a housing (energy storage module housing) 1 as a casing (container), a battery cell 2 housed in the housing 1, and tab leads 8a, 8b for inputting and outputting electricity to and from the battery cell 2.

[0273] The housing 1 is composed of two skin sheets 10, one above the other. The skin sheets 10 are made of a laminate material L1, which will be described later, and are formed using techniques such as deep drawing and extrusion molding. The upper skin sheet 10 has a shape that is upside down compared to the lower skin sheet 10, and both skin sheets 10 have substantially the same shape.

[0274] In this embodiment, the lower skin sheet 10 has a downward recess formed over the entire middle region except for the outer peripheral edge, forming a rectangular parallelepiped recess 11, and an outwardly protruding flange 12 is integrally formed on the outer periphery of the opening edge of the recess 11.

[0275] As already mentioned, the upper skin sheet 10 has a shape obtained by inverting the lower skin sheet 10 upside down, and has a rectangular parallelepiped-shaped recessed portion 11 formed to bulge upward, and a flange portion 12 integrally formed on the outer peripheral edge of the recessed portion (bulging portion) 11 so as to protrude outward.

[0276] The surface sheet 10 is made of a laminate material L1 which is a laminate sheet or film having flexibility and pliability.

[0277] In this embodiment, the laminate material L1 has a basic structure of either a three-layer structure in which a protective layer 53 / barrier layer 51 / battery fixing layer 55 are stacked from the top (outer surface) in the order shown in Figure 3D, or a four-layer structure in which a protective layer 53 / barrier layer 51 / thermal adhesive layer 52 / battery fixing layer 55 are stacked from the top (outer surface) in the order shown in Figure 3E.

[0278] In this embodiment, when the laminate material L1 has the three-layer structure shown in FIG. 3D, the battery fixing layer 55 functions as a thermal adhesive layer and also serves as a thermal adhesive layer.

[0279] As the metal constituting the barrier layer 51, aluminum (aluminum foil) and stainless steel (stainless steel foil) can be suitably used.

[0280] As the aluminum foil, aluminum foils of JIS aluminum alloy numbers 1000 series, 3000 series, 5000 series, and 8000 series can be suitably used, and among these, it is particularly preferable to use 8000 series aluminum foil.

[0281] Furthermore, the aluminum foil to be used preferably has a thickness of 30 μm to 200 μm, more preferably 60 μm to 150 μm.

[0282] As the stainless steel foil, austenitic stainless steel (stainless steel foil) such as JIS symbols (SUS symbols) SUS304, SUS301, SUS316, etc. can be suitably used, and among these, it is particularly preferable to use SUS304.

[0283] Furthermore, the stainless steel foil to be used preferably has a thickness of 20 μm to 150 μm, more preferably 30 μm to 100 μm.

[0284] It is preferable that the aluminum foil and stainless steel foil used as the barrier layer 51 are both tempered to O material.

[0285] When using aluminum foil as the barrier layer 51, it is preferable to form an underlayer on both sides. The underlayer can be formed of a chemical conversion coating such as chromate treatment, silicate treatment, or zirconium-based chemical conversion treatment. The thickness of the underlayer varies depending on the treatment method, but the amount of chromium deposited (per side) on the chemically treated surface of the aluminum foil is 0.1 mg / m 2 ~50mg / m 2 It is advisable to adjust the concentration to 2 mg / m 2 ~20mg / m 2 It is best to adjust it to

[0286] The protective layer 53 laminated on the outer surface of the barrier layer 51 is preferably made of a heat-resistant resin, particularly a resin having a melting point 20° C. or higher than that of the resin constituting the thermal adhesive layer 52 .

[0287] The protective layer 53 is preferably made of a biaxially oriented film, such as a biaxially oriented polyester film [polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc.], a biaxially oriented polyamide film (ONY) [PA6, PA66, etc.], or a biaxially oriented polypropylene film (OPP).

[0288] The protective layer 53 preferably has a thickness of 5 μm to 100 μm, and more preferably has a thickness of 9 μm to 50 μm.

[0289] In this embodiment, the resin film that constitutes the protective layer 53 is adhered and fixed to the outer surface (one surface) of the barrier layer 51 via an adhesive.

[0290] The thermal adhesive layer 52 laminated on the inner surface of the barrier layer 51 as needed is preferably made of a resin having a melting point 10° C. or higher than that of the resin constituting the battery fixing layer 55 described below.

[0291] As the thermal adhesive layer 52, a film of unstretched polyethylene (HDPE, LLDPE), a film of unstretched polypropylene (CPP), an acid-modified polyolefin resin film, or the like can be suitably used.

[0292] The thermal adhesive layer 52 preferably has a thickness of 30 μm to 100 μm, more preferably 40 μm to 80 μm.

[0293] In addition, as a method for attaching the thermal adhesive layer 52 to the barrier layer 51, a dry lamination method may be used in which a resin film as the thermal adhesive layer 52 is attached to the metal foil as the barrier layer 51 using a two-component curing adhesive, or an extrusion lamination method may be used in which a resin as the thermal adhesive layer 52 is extruded in the form of a film and directly attached to the metal foil as the barrier layer 51.

[0294] A heat-sealable resin having a melting point of 80° C. to 110° C. is preferably used for battery fixing layer 55. For example, a resin containing an olefin polymer having a carboxylic acid can be suitably used. Specifically, an ionomer resin, EMAA (ethylene-methacrylic acid copolymer), EEA (ethylene-ethyl acrylate copolymer), EMA (ethylene-methyl acrylate copolymer), etc. can be suitably used.

[0295] The above resin for the battery fixing layer 55 may be attached directly to the barrier layer 51 or the thermal adhesive layer 52 by extrusion lamination, or the above resin film for the battery fixing layer 55 may be attached by dry lamination using an adhesive, or it may be coated on a corona-treated surface of a PE film (HDPE, LLDPE) or a PP film and then attached.

[0296] The thickness of battery fixing layer 55 is preferably adjusted to 15 μm to 80 μm, more preferably 20 μm to 60 μm, when using a dry lamination method (resin film adhesion method) or an extrusion lamination method, and is preferably adjusted to 2 μm to 15 μm, more preferably 3 μm to 10 μm when using a coating method.

[0297] When the resin for the battery fixing layer 55 is attached by the resin film method, extrusion lamination method, or coating method, an inorganic substance (anti-blocking agent) such as silica or a slip agent such as a fatty acid amide may be added to prevent blocking when the battery is wound into a coil.

[0298] This battery fastening layer 55 is to be fastened to the outer surface (outermost layer) of the battery 2 housed in the housing 1 as will be described later.

[0299] In this embodiment, the resin constituting the battery fixing layer 55, i.e., the resin containing an olefin polymer having a carboxylic acid, has a functional group and is a resin that can be thermally bonded to both metal and resin, and can be fixed to the outer surface of the single battery 2 whether it is made of metal or resin.

[0300] Here, the outermost layer of the cylindrical battery used as the cell 2 is covered with an insulating, heat-shrinkable resin tube (made of polyethylene, vinyl chloride, etc.). Furthermore, the outermost layer of the prismatic battery is either left as a metal case or is covered with an insulating, heat-shrinkable resin tube. Furthermore, the outermost layer of the laminated battery is covered with a polyethylene terephthalate (PET) film or a biaxially oriented polyamide (ONY) film.

[0301] For example, if the outermost layer of the cylindrical battery of the cell 2 is a polyethylene heat-shrinkable tube, then ionomer, LDPE, LLDPE, EMAA, EEA, or the like may be used for the battery fastening layer 55. Furthermore, if the outermost layer of the prismatic battery as the cell 2 is a metal case (aluminum, stainless steel, or the like) or a vinyl chloride heat-shrinkable tube, then ionomer, EMAA, EEA, or the like may be used for the battery fastening layer 55. Furthermore, if the outermost layer of the laminate battery of the cell 2 is a polyethylene terephthalate (PET) film or a biaxially stretched polyamide (ONY) film, then ionomer, EMAA, EEA, or the like may be used for the battery fastening layer 55.

[0302] The laminate material L1 having the above configuration is used as the sheet material for the skin sheets, and the sheet material is recessed and cut to form the upper and lower skin sheets 10. As will be described later, the flange portions 12 of the upper and lower skin sheets 10 are thermally fused (thermally adhered) to each other to form the energy storage module housing 1. In this housing 1, the recessed portions 11 of the upper and lower skin sheets 10 form a rectangular parallelepiped battery housing portion 15.

[0303] 3B and 3C, the cell 2 used in this embodiment is a commercially available prismatic 9V dry cell battery. Needless to say, this cell 2 has a prismatic shape with a positive electrode and a negative electrode arranged side by side on one side.

[0304] In the present invention, the unit cells housed in the housing 1 can be any type of battery that can be used alone, i.e., a battery in which the battery elements are enclosed in a case and electrodes such as a positive and negative electrodes are provided externally. For example, batteries that can be used include the above-mentioned prismatic dry batteries and cylindrical dry batteries in which the battery elements are enclosed in a metal case, batteries in which the battery elements are enclosed in a plastic case, and laminated batteries (laminated batteries) in which the battery elements are enclosed in a bag-shaped film such as a laminated material. Furthermore, in the present invention, the batteries housed in the housing 1 are not limited to primary batteries, and can also be secondary batteries.

[0305] Tab leads 8a and 8b are used as electrodes. The tab leads 8a and 8b each include a strip-shaped tab lead body 81 and a covering film 82 provided on both sides of the center of the tab lead body 81. The covering film 82 is provided in correspondence with the flange portion 12 of the skin sheet 10, and is fixed to the flange portion 12 by heat fusion as described below.

[0306] As shown in Figures 3B and 3C, in this embodiment, three single cells 2 are arranged side by side in the recessed portion 11 of the lower skin sheet 10, with their electrode sides positioned on the right side of Figures 3B and 3C.

[0307] Each cell 2 has a battery snap 21 with a lead wire attached to its electrode. The negative electrode lead wire 21b of the battery snap 21 of the positive cell 2 and the positive electrode lead wire 21a of the battery snap 21 of the negative cell 2 are connected and fixed by soldering between adjacent cells 2, thereby connecting the cells 2 in series via the battery snaps 21. Furthermore, a positive electrode tab lead 8a is disposed on the positive electrode end (right end) of the flange portion 12 of the skin sheet 10, and a negative electrode tab lead 8b is disposed on the negative electrode end (left end). The positive electrode lead wire 21a of the battery snap 21 of the cell 2 located closest to the positive electrode (right side) among the cells 2 is connected and fixed by soldering to the base end (inner end) of the positive electrode tab lead 8a, and the tip end (outer end) of the positive electrode tab lead 8a is disposed so that it is pulled outward from the positive electrode side. Furthermore, the negative electrode lead wire 21b of the battery snap 21 of the cell 2 arranged on the most negative electrode side (left side) is connected and fixed by soldering to the base end (inner end) of the negative electrode tab lead 8b, and the tip end (outer end) of the negative electrode tab lead 8b is arranged so that it is drawn outward from the negative electrode side. In this way, the multiple cells 2 are arranged so that the potential difference between the two tab leads 8a, 8b is the largest.

[0308] In this way, the lower half of the cell 2 is accommodated in the recess 11 of the lower skin sheet 10, and the tab leads 8a, 8b are arranged with their covering films 82 on the flanges 12. Then, the upper skin sheet 10 is accommodated in its recess 11 with the upper half of the cell 2, and the flanges 12 are placed over the covering films 82 of the tab leads 8a, 8b, with the flanges 12 of both skin sheets 10 overlapping each other.

[0309] In this state, the flanges 12 of the skin sheets 10 are sandwiched between a pair of upper and lower heat seal dies and heated under pressure, whereby the battery fastening layers 55 of the flanges 12, and in some cases the thermal adhesive layers 52, are heat-sealed and joined together, and the flanges 12 of the skin sheets 10 and the covering films 82 of the tab leads 8a, 8b are heat-sealed and joined together. In this way, the upper and lower skin sheets 10 enclose the cells 2, and the electricity storage module is assembled.

[0310] In this embodiment, the battery fixing layers 55 in the recessed portions 11 of the skin sheets 10 constituting the housing 1 are fixed to the outer surfaces (outermost layers) of the cells 2 by thermal adhesion. That is, the portions (recessed portions 11) of both skin sheets 10 corresponding to the cells 2 are sandwiched between a pair of upper and lower heat seal dies or the like and heated while being pressed.

[0311] Here, when the thermal adhesive layer 52 is provided between the barrier layer 51 and the battery fixing layer 55 as shown in Fig. 3E, short-circuiting between the barrier layer 51 and the tab leads 8a, 8b can be more reliably prevented. Specifically, if the thermal adhesive layer 52 is not provided between the barrier layer 51 and the battery fixing layer 55 as shown in Fig. 4A, when the flange portions 12 of the skin sheets 10 are thermally sealed together, if the sealing conditions, such as temperature, pressure, and time, are quite severe, the battery fixing layer 55 may melt and become thinner than expected, causing the barrier layer (metal foil layer) 51 to be partially exposed and come into contact with the tab leads 8a, 8b, resulting in a short circuit and a decrease in electrical insulation. In contrast, when the thermal adhesive layer 52 is provided as shown in Fig. 3E, even if the battery fixing layer 55 melts and becomes thinner than expected during heat sealing of the skin sheets 10, the thermal adhesive layer 52 remains on the inner surface of the barrier layer 51, thereby reliably preventing the barrier layer 51 from short-circuiting with the tab leads 8a, 8b. Furthermore, the skin sheets 10 can be sealed together by thermal adhesion using the thermal adhesive layer 52, so that the airtightness can be reliably maintained.

[0312] In this embodiment, a one-stage seal (one-stage seal method) may be adopted in which the battery fixing process of thermally bonding the outer surface of the battery 2 to the inner surface of the skin sheet 10 and the sealing process of thermally bonding the skin sheets 10 together are performed simultaneously, or a two-stage seal (two-stage seal method) in which these processes are performed separately may be adopted.

[0313] In the electricity storage module of this embodiment thus fabricated, the tab leads 8a and 8b are connected to a power supply section of the electric motor to supply electric power, thereby driving the electric motor.

[0314] According to the energy storage module of this embodiment having the above-described configuration, the housing 1 is formed of a skin sheet 10 made of laminate material L1, which makes it possible to reduce weight compared to a case where a metal housing is used, ensure sufficient electrical insulation, and further improve heat dissipation and strength compared to a case where the housing is made of a heat-shrinkable resin film.

[0315] Furthermore, in the energy storage module of this embodiment, the battery fixing layer 55 is formed on the inner surface of the casing 1, and the battery fixing layer 55 is thermally bonded to the outer surface of the cell 2, so that the cell 2 can be fixed in position with sufficient strength to the casing 1. Therefore, even if the cell 2 is subjected to vibration or impact, it is possible to reliably prevent displacement or deformation of the cell 2 relative to the casing 1, and to prevent the occurrence of short circuits and the like due to such displacement or deformation, thereby achieving high reliability.

[0316] For reference, it is preferable to adjust the ratio (proportion) of the area where the battery fastening layer 55 is thermally bonded to the entire outer surface of the plurality of cells 2 to 25% or more.

[0317] Furthermore, in this embodiment, when a battery fastening layer 55 having a melting point of 80°C to 120°C is used, the melting point is at least 80°C or higher, so that even when used under high temperatures such as on a hot summer day, the battery fastening layer 55 can be prevented from melting and releasing its fastening to the cells 2, and the cells 2 can be stably fixed. Furthermore, because the melting point is at most 120°C or lower, there is no need for a battery fastening process at a high temperature exceeding 120°C, and adverse effects of heat on the cells 2 can be avoided. For example, the cells 2 can be fastened to the housing 1 at a temperature lower than the temperature at which the pores of the separators of the cells 2 become clogged, and the performance of the energy storage module can be reliably ensured, and high quality can be maintained.

[0318] Furthermore, in this embodiment, when the battery fixing layer 55 is made of a resin containing an olefin polymer having a carboxylic acid, the adhesiveness is high, so that the skin sheet 10 can be reliably thermally bonded to the unit cell 2, and displacement of the unit cell 2 can be more reliably prevented.

[0319] Furthermore, in this embodiment, when the thermal adhesive layer 52 is provided between the barrier layer 51 and the battery fixing layer 55, as described above, even if the battery fixing layer 55 melts more than expected, sufficient insulation can be ensured by the thermal adhesive layer 52. Note that, in order to more reliably prevent a decrease in insulation due to melting of the battery fixing layer 55, as described above, it is preferable to use a thermal adhesive layer 52 having a melting point 10° C. or more higher than that of the battery fixing layer 55.

[0320] In this embodiment, the heat resistance can be further improved by forming the protective layer 53, which has excellent heat resistance, on the outer surface side of the barrier layer 51. To ensure this improved heat resistance, it is preferable to use a material for the protective layer 53 that has a melting point 20°C or more higher than that of the thermal adhesive layer 52.

[0321] In the above embodiment, an example has been described in which three cells 2 are housed in the housing 1, but in the present invention, the number of cells 2 housed is not particularly limited as long as it is two or more.

[0322] In the above embodiment, the case where the housing 1 is formed using two skin sheets 10 has been described as an example, but this is not limited thereto, and in the present invention, the housing may be formed using one or three or more skin sheets.

[0323] In the above embodiment, the case where a recessed skin sheet 10 (molded product) is used has been described as an example, but the present invention is not limited to this, and a bag-shaped housing may also be formed by overlapping two unmolded, flat skin sheets (non-molded products) and thermally bonding their outer peripheries. Furthermore, when forming a housing using multiple skin sheets, the housing may be formed by using only some skin sheets as molded products and the other skin sheets as non-molded products. [Example]

[0324] <Example 3-1> As will be described below, in the examples and comparative examples, energy storage modules having the same shape as the energy storage module of the third embodiment shown in FIGS. 3A to 3C were fabricated.

[0325] [Table 3]

[0326] (1) Preparation of the epidermal sheet 10 As shown in Table 3, a 12 μm thick protective layer 53 made of polyethylene terephthalate (PET) was laminated on the outer surface of a 120 μm thick aluminum foil (A8021H-O) barrier layer 51 via a urethane adhesive, while a 60 μm thick battery fixing layer 55 made of ionomer resin (melting point: 90°C) was laminated on the inner surface of the barrier layer 51 via a urethane adhesive, thereby producing a laminate material L1 for the skin sheet 10.

[0327] This laminate material L1 was cut to a width of 100 mm and a length of 250 mm, and deep-drawn so that the ionomer surface (battery fixing layer 55) was on the inside to form a recess 11 having a width of 27 mm, a length of 150 mm, and a depth of 9 mm. The material was then cut to a peripheral width of 10 mm to form a flange 12, thereby obtaining a molded lower skin sheet 10.

[0328] The same laminate material L1 as above was cut and shaped in the same manner, and then turned upside down to obtain a shaped upper skin sheet 10.

[0329] (2) Tab lead fabrication A film made from maleic anhydride-modified polyethylene (Modic M522 manufactured by Mitsubishi Chemical Corporation) having a thickness of 0.1 mm, a width of 14 mm and a length of 15 mm was bonded to both sides of the center of an aluminum plate having a thickness of 0.2 mm, a width of 10 mm and a length of 30 mm to prepare a positive electrode tab lead 8a.

[0330] A film made from maleic anhydride-modified polyethylene (Modic M522 manufactured by Mitsubishi Chemical Corporation) having a thickness of 0.1 mm, a width of 14 mm and a length of 15 mm was bonded to both sides of the center of a nickel plate having a thickness of 0.2 mm, a width of 10 mm and a length of 30 mm to prepare a negative electrode tab lead 8b.

[0331] (3) Preparation of the energy storage device (single cell) Three rectangular 9V dry batteries were prepared as the cells 2. The dimensions of the cells were 26.5 mm in length, 48.5 mm in width, and 17.5 mm in height. The outermost layer of the cells 2 was a polyethylene shrink tube.

[0332] (4) Fabrication of energy storage module As in embodiment 3 shown in FIGS. 3A to 3C, three cells 2 connected in series by battery snaps 21 were housed in the recess 11 of the lower skin sheet 10, with the positive electrode lead wire 21a of the most positive battery snap 21 soldered to the base end (inner end) of the positive electrode tab lead 8a, and the negative electrode lead wire 21b of the most negative battery snap 21 soldered to the base end (inner end) of the negative electrode tab lead 8b.

[0333] Next, the upper skin sheet 10 is placed so as to cover the cells 2 housed in the lower skin sheet 10, and the flange portions 12 of the upper skin sheet 10 are placed over the flange portions 12 of the lower skin sheet 10. At this time, the covering films 82 of the tab leads 8a, 8b are sandwiched between the flange portions 12 of the upper and lower skin sheets 10, and the tips (outer ends) of the tab leads 8a, 8b are placed so as to be pulled out to the outside. In this way, a storage module in a provisionally assembled state (unjoined state) was produced.

[0334] Next, this temporary assembly was subjected to a two-stage heat-sealing process. In the first stage, the flanges 12 at the outer peripheries of the upper and lower skin sheets 10 were sandwiched from above and below using a sealing mold and heated to heat-seal the flanges 12 together and also heat-seal the flanges 12 and the covering films 82 of the tab leads 8a and 8b, sealing the cell 2 with the skin sheets 10 (housing 1).

[0335] In the second sealing step, the bottom wall (upper wall) of the recess 11 of the skin sheet 10 was pressed from above and below with a sealing mold and pressed against both sides of the cell 2, and then heated to thermally bond the inner surface of the recess of the skin sheet 10 to the outer surface of the cell 2. In this way, the electricity storage module of Example 3-1 was produced.

[0336] The first sealing conditions were 130°C x 0.3 MPa x 7 seconds, and the second sealing conditions were 100°C x 0.3 MPa x 7 seconds.

[0337] In the electricity storage module of Example 3-1, the ratio of the area thermally bonded to battery fastening layer 55 to the surface area of ​​the three unit cells was 30.8%.

[0338] <Example 3-2> As shown in Table 3, a 25 μm thick protective layer 53 made of biaxially oriented polyamide (ONY) was laminated via a urethane adhesive on the outer surface of a barrier layer 51 made of an 80 μm thick aluminum foil (A3003H-O), while a 40 μm thick thermal adhesive layer 52 made of LLDPE was laminated via a urethane adhesive on the inner surface of the barrier layer 51, and further, EMAA (melting point: 100°C) was laminated to a thickness of 20 μm on the inner surface of the thermal adhesive layer 52 by extrusion lamination, thereby producing a laminate material L1 for the skin sheet 10.

[0339] This laminate material L1 was cut and shaped in the same manner as above, with the EMAA surface (battery fixing layer 55) facing inward, to obtain the shaped upper and lower skin sheets 10 of Example 3-2.

[0340] Three square 9V dry batteries with a SUS case as the outermost layer were prepared as the cells 2. The size of these cells 2 was the same as that of the cells 2 in Example 3-1.

[0341] A temporary assembly for the storage module of Example 3-2 was produced in the same manner as in Example 3-1 above, using the upper and lower skin sheets 10 of Example 3-2, the single battery 2 of Example 3-2, and tab leads 8a and 8b similar to those of Example 3-1 above.

[0342] This temporary assembly was subjected to a two-stage thermal sealing process. In the first stage, the flanges 12 of the upper and lower skin sheets 10 were thermally fused together under sealing conditions of 130°C x 0.3 MPa x 7 seconds. In the second stage, the inner circumferential surface of the recess in the skin sheet 10 was thermally bonded (thermally fused) to the outer surface of the cell 2 under sealing conditions of 110°C x 0.3 MPa x 10 seconds.

[0343] The ratio of the area thermally bonded to the battery fastening layer 55 to the surface area of ​​the three unit cells was 49.5%.

[0344] <Example 3-3> As shown in Table 3, a 12 μm thick protective layer 53 made of polyethylene terephthalate (PET) was laminated on the outer surface of a 80 μm thick barrier layer 51 made of aluminum foil (A8021H-O) via a urethane adhesive, while a 40 μm thick battery fixing layer 55 made of EEA (melting point: 95°C) was laminated on the inner surface of the barrier layer 51 via a urethane adhesive, thereby producing a laminate material L1 for the skin sheet 10.

[0345] This laminate material L1 was cut and shaped in the same manner as above, with the EEA surface (battery fixing layer 55) facing inward, to obtain the shaped upper and lower skin sheets 10 of Example 3-3.

[0346] Using the upper and lower skin sheets 10 of Example 3-3 and the same unit cells 2 and tab leads 8a, 8b as in Example 3-1, a temporary assembly for the storage module of Example 3-3 was produced in the same manner as in Example 3-1.

[0347] This temporary assembly was subjected to a two-stage thermal sealing process. In the first stage, the flanges 12 of the upper and lower skin sheets 10 were thermally fused together under sealing conditions of 130°C x 0.3 MPa x 7 seconds. In the second stage, the inner circumferential surface of the recess in the skin sheet 10 was thermally bonded (thermally fused) to the outer surface of the cell 2 under sealing conditions of 110°C x 0.3 MPa x 7 seconds.

[0348] The ratio of the area thermally bonded to the battery fastening layer 55 to the surface area of ​​the three unit cells was 49.5%.

[0349] <Evaluation of formability> Each laminate material of the examples was cut to prepare a molding blank having a width of 100 mm and a length of 250 mm. As described above, each blank of the examples was deep-drawn so that the battery fixing layer 55 was on the inside, and a recess 11 having a width of 27 mm, a length of 150 mm, and a depth of 9 mm was formed.

[0350] The molded articles of each example were observed in a dark room by a light transmission method to check for the presence or absence of molding cracks, pinholes, etc.

[0351] The samples that did not have molding cracks or pinholes were evaluated as "Good", and the samples that had cracks or pinholes were evaluated as "Poor." The evaluation results are also shown in Table 3.

[0352] <Voltage evaluation> For the energy storage modules manufactured in Examples 3-1 to 3-3 above, the voltage between the positive and negative electrode tab leads 8a and 3b drawn out to the outside was measured using a tester. The results are shown in Table 3.

[0353] <Evaluation of the adhesion between the housing and the cell> The energy storage modules manufactured in Examples 3-1 to 3-3 above were subjected to a drop test in which they were dropped from a height of 1 m onto a concrete floor. In this drop test, the long side of each energy storage module was allowed to freely drop 10 times, and then the short side was allowed to freely drop 10 times. After that, each energy storage module was vibrated by hand to check whether the cells housed in the energy storage module moved, and the casing (skin sheet) was cut open to visually check the adhesion state between the cells and the exterior material.

[0354] The cells in which all three were adhered to the housing (surface sheet) were evaluated as "Good", and the cells in which one or more of the three cells were peeled off from the housing were evaluated as "Poor". The results are shown in Table 3.

[0355] As is clear from Table 3, the energy storage modules of Examples 3-1 to 3-3, which incorporate the gist of the present invention, ensure good formability while also providing stable adhesion of the cells to the casing, thereby reliably preventing the cells from shifting out of position relative to the casing.

[0356] <Embodiment 4> 4A to 4C are diagrams showing an electricity storage module according to a fourth embodiment of the present invention. In the following description, to facilitate understanding of the invention, the up-down direction in FIG. 4B will be referred to as the "up-down direction (thickness direction)."

[0357] As shown in Figures 4A to 4C, the energy storage module of this embodiment has, as its basic components, a housing (energy storage module housing) 1 as a casing (container), a battery cell 2 housed in the housing 1, and tab leads 8a, 8b for inputting and outputting electricity to and from the battery cell 2.

[0358] The housing 1 is composed of two skin sheets 10, one above the other. The skin sheets 10 are made of a laminate material L1, which will be described later, and are formed using techniques such as deep drawing and extrusion molding. The upper skin sheet 10 has a shape that is upside down compared to the lower skin sheet 10, and both skin sheets 10 have substantially the same shape.

[0359] In this embodiment, the lower skin sheet 10 has a downward recess formed over the entire middle region except for the outer peripheral edge, forming a rectangular parallelepiped recess 11, and an outwardly protruding flange 12 is integrally formed on the outer periphery of the opening edge of the recess 11.

[0360] As already mentioned, the upper skin sheet 10 has a shape obtained by inverting the lower skin sheet 10 upside down, and has a rectangular parallelepiped-shaped recessed portion 11 formed to bulge upward, and a flange portion 12 integrally formed on the outer peripheral edge of the recessed portion (bulging portion) 11 so as to protrude outward.

[0361] The surface sheet 10 is made of a laminate material L1 which is a laminate sheet or film having flexibility and pliability.

[0362] In this embodiment, the laminate material L1 has a basic three-layer structure in which a protective layer 53 / outer adhesive layer 71 / barrier layer 51 / inner adhesive layer 72 / thermal fusion layer 6 are laminated from the top (outer surface side) in this order as shown in Figure 4D.

[0363] The metal foil that constitutes the barrier layer 51 may be an aluminum foil, a copper foil, a nickel foil, a titanium foil, a nickel-plated foil, a nickel-copper clad metal foil, or the like.

[0364] The barrier layer 51 preferably has a thickness of 40 μm to 200 μm, and more preferably has a thickness of 60 μm to 150 μm.

[0365] It is preferable to form an underlayer on both sides of the metal foil that constitutes the barrier layer 51. The underlayer can be formed by a chemical conversion coating such as chromate treatment, silicate treatment, or zirconium-based chemical conversion treatment. The thickness of the underlayer varies depending on the treatment method. For example, in the case of chromate treatment, the amount of chromium deposited (per side) on the chemical conversion treated surface of the metal foil is 0.1 mg / m 2 ~50mg / m 2 It is advisable to adjust the concentration to 2 mg / m 2 ~20mg / m 2 It is best to adjust it to

[0366] The protective layer 53 laminated on the outer surface of the barrier layer 51 is preferably made of a heat-resistant resin, particularly a resin having a melting point 20° C. or more higher than that of the resin constituting the thermal adhesive layer 6 .

[0367] The protective layer 53 is preferably made of a biaxially oriented film, such as a biaxially oriented polyester film [polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc.], a biaxially oriented polyamide film (ONY) [PA6, PA66, etc.], or a biaxially oriented polypropylene film (OPP).

[0368] The protective layer 53 preferably has a thickness of 5 μm to 100 μm, and more preferably has a thickness of 9 μm to 50 μm.

[0369] Furthermore, the protective layer 53 is not limited to a single layer made of one type of resin, but may be configured to have a multi-layer structure in which the same or different types of resins are laminated.

[0370] The outer adhesive layer 71 that bonds the protective layer 53 to the outer surface (one side) of the barrier layer 51 is preferably made of a two-component curing adhesive, etc. For example, a two-component curing adhesive that is made up of a first component consisting of one or more polyols selected from the group consisting of polyurethane polyols, polyester polyols, polyether polyols, and polyester urethane polyols, and a second component (curing agent) consisting of an isocyanate can be suitably used.

[0371] The thickness of the outer adhesive layer 71 is preferably set to 2 μm to 5 μm.

[0372] The heat-sealing layer 6 constitutes a thermal adhesive layer and has insulating properties. As the heat-sealing layer 6, a PE film (LDPE, LLDPE, HDPE, etc.), an acid-modified polyolefin resin film, a non-oriented polypropylene film (CPP), etc. can be suitably used.

[0373] The heat-sealing layer 6 can be made of a single resin layer (resin film, etc.) such as CPP, but can also be made of a multi-layer body made of a plurality of resin layers (resin films, etc.).

[0374] When the thermal seal layer 6 is formed from a multi-layer structure, it is preferable to select multiple resins of the same type but with different melting points, as this makes them less likely to peel from each other. In particular, it is preferable to form the thermal seal layer 6 from a laminate including a high-melting-point layer and a low-melting-point layer with a melting point difference of 10°C or more. That is, by performing the thermal seal process (sealing process) as described below at a temperature between the melting points of the high-melting-point layer and the low-melting-point layer, only the low-melting-point layer melts and is thermally sealed while the high-melting-point layer does not melt, so that the high-melting-point layer remains sufficiently intact, ensuring good insulation.

[0375] For example, as shown in FIG. 4E, it is preferable that the heat-sealing layer 6 is configured as a three-layered composite having a high-melting point layer 62 disposed in the middle and made of a resin such as propylene-ethylene block copolymer (bPP) or HDPE, and low-melting point layers 61, 63 laminated on both the inner and outer surfaces of the high-melting point layer 62 and made of a resin such as propylene-ethylene random copolymer (rPP), LLDPE or LDPE.

[0376] The overall thickness of the thermal adhesive layer 6 is preferably set to 80 μm to 200 μm, and more preferably set to 100 μm to 150 μm.

[0377] Furthermore, the thickness of the low melting point layer is preferably set to 5 μm to 20 μm, and more preferably set to 10 μm to 15 μm.

[0378] Furthermore, the thickness of the high melting point layer is preferably set to 50 μm to 180 μm, and more preferably to 60 μm to 150 μm.

[0379] That is, the energy storage module of the present invention is suitably used as a high-power battery, but in a high-power battery, a large current flows through the built-in cells 2 with large voltage capacity, so there is a high possibility that the current-carrying parts will reach a high temperature due to Joule heat, and the parts of the heat-sealing layer 6 of the casing 1 that are in contact with the hot tab leads 8a, 8b will melt and disappear, and the tab leads 8a, 8b may short-circuit to the barrier layer 51, which is a metal foil layer of the casing 1. Therefore, as described above, by setting the heat-sealing layer 6 to a large thickness as described above or providing the high-melting point layer 62, the current-carrying parts will not reach a high temperature, and the heat-sealing layer 6 will remain even at the high temperature during heat sealing as described above, so internal short-circuiting can be prevented, sufficient insulation can be ensured, and high reliability can be maintained.

[0380] If the heat-sealing layer 6 becomes too thick, it is necessary to set the temperature in the sealing conditions during heat sealing higher in order to ensure that the heat-sealing process (heat sealing) is carried out reliably, which is undesirable as it may cause the heat-sealing layer 6 to melt more than necessary and become thinner, resulting in a decrease in insulation properties.

[0381] The inner adhesive layer 72 that adheres the heat-sealing layer 6 to the inner surface (other surface) of the barrier layer 51 is preferably made of a polyurethane adhesive, an acrylic adhesive, an epoxy adhesive, a polyolefin adhesive, an elastomer adhesive, a fluorine adhesive, an acid-modified polypropylene adhesive, or the like.

[0382] The thickness of this adhesive layer 72 is preferably set to 2 μm to 5 μm.

[0383] When the thermal adhesive layer 6 is bonded to the barrier layer 51, a dry lamination method using a two-component curing adhesive may be used, or an extrusion lamination method may be used.

[0384] It is preferable to add an insulating filler to the inner adhesive layer 72 that bonds the thermal adhesive layer 6 to the barrier layer 51 in order to improve the insulating properties.

[0385] The insulating filler must have a particle diameter smaller than the thickness of the inner adhesive layer 72. For example, an insulating filler having a particle diameter of 2 μm or less can be preferably used. Furthermore, inorganic oxides such as SiO2 and TiO2 can be preferably used as the insulating filler.

[0386] The laminate material L1 having the above configuration is used as the sheet material for the skin sheets, and the sheet material is recessed and cut to form the upper and lower skin sheets 10. As will be described later, the flange portions 12 of the upper and lower skin sheets 10 are thermally fused (thermally adhered) to each other to form the energy storage module housing 1. In this housing 1, the recessed portions 11 of the upper and lower skin sheets 10 form a rectangular parallelepiped battery housing portion 15.

[0387] In this embodiment, the term "surface sheet" includes both a sheet before molding (non-molded product) and a sheet after molding (molded product).

[0388] 4B and 4C, the cell 2 used in this embodiment is a commercially available prismatic 9V dry cell battery. Needless to say, this cell 2 has a prismatic shape with a positive electrode and a negative electrode arranged side by side on one side.

[0389] In the present invention, the unit cells housed in the housing 1 can be any type of battery that can be used alone, i.e., a battery in which the battery elements are enclosed in a case and electrodes such as a positive and negative electrodes are provided externally. For example, batteries that can be used include the above-mentioned prismatic dry batteries and cylindrical dry batteries in which the battery elements are enclosed in a metal case, batteries in which the battery elements are enclosed in a plastic case, and laminated batteries (laminated batteries) in which the battery elements are enclosed in a bag-shaped film such as a laminated material. Furthermore, in the present invention, the batteries housed in the housing 1 are not limited to primary batteries, and can also be secondary batteries.

[0390] Tab leads 8a and 8b are used as electrodes. The tab leads 8a and 8b each include a strip-shaped tab lead body 81 and a covering film 82 provided on both sides of the center of the tab lead body 81. The covering film 82 is provided in correspondence with the flange portion 12 of the skin sheet 10, and is fixed to the flange portion 12 by heat fusion as described below.

[0391] As shown in Figures 4B and 4C, in this embodiment, three single cells 2 are arranged side by side in the recessed portion 11 of the lower skin sheet 10, with their electrode sides positioned on the right side of Figures 4B and 4C.

[0392] Each cell 2 has a battery snap 21 with a lead wire attached to its electrode. The negative electrode lead wire 21b of the battery snap 21 of the positive cell 2 and the positive electrode lead wire 21a of the battery snap 21 of the negative cell 2 are connected and fixed by soldering between adjacent cells 2, thereby connecting the cells 2 in series via the battery snaps 21. Furthermore, a positive electrode tab lead 8a is disposed on the positive electrode end (right end) of the flange portion 12 of the skin sheet 10, and a negative electrode tab lead 8b is disposed on the negative electrode end (left end). The positive electrode lead wire 21a of the battery snap 21 of the cell 2 located closest to the positive electrode (right side) among the cells 2 is connected and fixed by soldering to the base end (inner end) of the positive electrode tab lead 8a, and the tip end (outer end) of the positive electrode tab lead 8a is disposed so that it is pulled outward from the positive electrode side. Furthermore, the negative electrode lead wire 21b of the battery snap 21 of the cell 2 arranged on the most negative electrode side (left side) is connected and fixed by soldering to the base end (inner end) of the negative electrode tab lead 8b, and the tip end (outer end) of the negative electrode tab lead 8b is arranged so that it is drawn outward from the negative electrode side. In this way, the multiple cells 2 are arranged so that the potential difference between the two tab leads 8a, 8b is the largest.

[0393] In this way, the lower half of the cell 2 is accommodated in the recess 11 of the lower skin sheet 10, and the tab leads 8a, 8b are arranged with their covering films 82 on the flanges 12. Then, the upper skin sheet 10 is accommodated in its recess 11 with the upper half of the cell 2, and the flanges 12 are placed over the covering films 82 of the tab leads 8a, 8b, with the flanges 12 of both skin sheets 10 overlapping each other.

[0394] In this state, the flanges 12 of the skin sheets 10 are sandwiched between a pair of upper and lower heat seal dies and heated under pressure, whereby the heat-sealing layers 6 of the flanges 12 are heat-sealed to each other and joined together, and the flanges 12 of the skin sheets 10 are heat-sealed to the covering films 82 of the tab leads 8a, 8b to be joined together. In this way, the upper and lower skin sheets 10 enclose the cells 2, and the electricity storage module is assembled.

[0395] In this embodiment, it is preferable to bond the inner surface of the recessed portion 11 of the skin sheet 10 constituting the housing 1 to the outer surface of the cell 2. Examples of the bonding method include a method using a bonding tape, a method using heat fusion (thermal adhesion), and a method using an adhesive.

[0396] As a means for using tape, double-sided tape such as adhesive tape can be used. For example, the outer circumferential surface of the cell 2 can be fixed to the inner circumferential surface of the housing 1 by using double-sided adhesive tape in which a silicon-based adhesive, an acrylic-based adhesive, or a rubber-based adhesive is applied to both sides of a film substrate (polyethylene terephthalate).

[0397] As a means of using heat fusion, if a heat-bondable resin is laminated in advance as an inner layer of the skin sheet 10 to the material used for the outer layer of the unit cell 2, the outer surface of the unit cell 2 can be fixed to the inner surface of the housing 1 by heating and pressurizing the part of the skin sheet 10 corresponding to the unit cell 2.

[0398] For reference, if the cell is a cylindrical or prismatic dry cell, the outermost layer is covered with an insulating, heat-shrinkable resin tube (made of polyolefin, vinyl chloride, etc.). Furthermore, if the cell is a laminated battery, the outermost layer is composed of a polyethylene terephthalate (PET) film or a biaxially oriented polyamide (ONY) film. Therefore, for a cylindrical dry cell whose outermost layer is a polyolefin tube, a CPP film, LDPE film, or LLDPE film can be used for the inner layer of the skin sheet 10. Furthermore, for a prismatic dry cell whose outermost layer is a vinyl chloride tube, an acid-modified PP film or an acid-modified PE film can be used for the inner layer of the skin sheet 10. Furthermore, for a laminated battery whose outermost layer is a polyethylene terephthalate (PET) film or a biaxially oriented polyamide (ONY) film, an ionomer can be used for the inner layer of the skin sheet 10.

[0399] As a means for using an adhesive, an adhesive may be applied to the outer layer of the cell 2 and dried to form an adhesive layer, and then the outer surface of the cell 2 can be fixed to the inner surface of the housing 1 by heating and pressurizing the portion of the skin sheet 10 corresponding to the cell 2. Examples of such adhesives include epoxy-urethane adhesives and modified acrylic adhesives, but it is more preferable to use an acid-modified polypropylene adhesive that uses blocked isocyanate as a curing agent.

[0400] When thermally bonding the outer surface of the cell 2 to the inner surface of the skin sheet 10, a one-stage seal (one-stage seal method) may be used in which the thermal bonding process between the skin sheet 10 and the cell 2 and the thermal bonding (sealing) process between the skin sheets 10 are performed simultaneously, as described above, or a two-stage seal (two-stage seal method) in which these processes are performed separately may be used.

[0401] In the electricity storage module of this embodiment thus fabricated, the tab leads 8a and 8b are connected to a power supply section of the electric motor to supply electric power, thereby driving the electric motor.

[0402] According to the energy storage module having the above-described configuration, an insulating heat-sealing layer 6 having a thickness of 80 μm or more is provided on the laminate material L1, which is the skin sheet 10 serving as the housing 1. This ensures that the heat-sealing layer 6 remains even at high temperatures during heat sealing of the skin sheet 10 and at high temperatures during power supply (when electricity is applied), ensuring sufficient insulation and effectively preventing the occurrence of internal short circuits.

[0403] Furthermore, in the energy storage module of this embodiment, when the heat-sealing layer 6 is constructed from a multi-layer body having two or more layers with different melting points and the low-melting-point layer 63 is arranged on the innermost side of the multi-layer body, the low-melting-point layer 63 is melted and heat-sealed during heat sealing, thereby ensuring that the heat-sealing process (sealing process) is carried out reliably while the high-melting-point layer 62 remains, thereby more reliably ensuring insulation.

[0404] In particular, in this embodiment, the high melting point layer 62 remains reliably, so that the insulating layer (thermal adhesive layer) can be reliably secured to a thickness of 50 μm or more, thereby providing a housing 1 with good insulating properties.

[0405] In addition, in this embodiment, when an adhesive having insulating properties is used as the inner adhesive layer 72 for adhering the thermal adhesive layer 6 to the barrier layer 51, the insulating properties can be further improved.

[0406] Furthermore, in this embodiment, when an insulating filler is added to the inner adhesive layer 72 to impart insulating properties, the insulating properties can be imparted to the inner adhesive layer 72 simply and reliably.

[0407] Furthermore, in the energy storage module of this embodiment, a laminate material L1 is used as the skin sheet 10 for the housing 1, which ensures weight reduction and insulation compared to when a metal housing is used, and also ensures sufficient insulation while achieving weight reduction compared to when a resin housing is used.

[0408] In the above embodiment, an example has been described in which three cells 2 are housed in the housing 1, but in the present invention, the number of cells 2 housed is not particularly limited as long as it is two or more.

[0409] In the above embodiment, the case where the housing 1 is formed using two skin sheets 10 has been described as an example, but this is not limited thereto, and in the present invention, the housing may be formed using one or three or more skin sheets.

[0410] In the above embodiment, the case where a recessed skin sheet 10 (molded product) is used has been described as an example, but the present invention is not limited to this, and a bag-shaped housing may also be formed by overlapping two unmolded, flat skin sheets (non-molded products) and thermally bonding their outer edges. Furthermore, when forming a housing using multiple skin sheets, the housing may be formed by using only some skin sheets as molded products and the other skin sheets as non-molded products, as shown in the following examples. [Example]

[0411] [Table 4]

[0412] <Example 4-1> (1) Preparation of laminate material L1 (surface sheet 10) As shown in Table 4, the laminate material L1 was prepared by laminating 12 μm of polyethylene terephthalate (PET), 3 μm of urethane adhesive, 120 μm of AL foil (A8021H-O), 3 μm of urethane adhesive, and 80 μm of unstretched polypropylene [a three-layer film made by extruding polypropylene consisting of random copolymer (rPP), block copolymer (bPP), and random copolymer (rPP)] from the outside in the order listed.

[0413] That is, a chemical conversion treatment solution consisting of polyacrylic acid, a trivalent chromium compound, water, and alcohol was applied to both sides of a 120 μm thick aluminum foil (alloy number "A8021H", temper "O material"), and the aluminum foil was dried at 150°C to form a chemical conversion coating on both sides, thereby preparing the aluminum foil for the barrier layer 51.

[0414] A urethane adhesive resin was applied to one side (inner surface) of the aluminum foil for the barrier layer 51 at a rate of 4 g / m using a roll coater. 2 The adhesive was applied to form an inner adhesive layer 72 having a thickness of 3 μm.

[0415] As shown in FIG. 4E, a resin film for the heat-sealing layer 6 having a three-layer structure in which a 12 μm thick low-melting-point layer made of rPP (melting point 137°C) having a thickness of 12 μm is laminated on both sides of a 56 μm thick high-melting-point layer 62 made of bPP (melting point 163°C) was attached to the inner surface of the barrier layer 51 via the inner adhesive layer 72, thereby producing the heat-sealing layer 6.

[0416] A urethane adhesive (thickness: 3 μm) was applied to the outer surface of the barrier layer 51 (the surface opposite to the thermal adhesive layer 6) to form an outer adhesive layer 71. Then, a polyethylene terephthalate film having a thickness of 12 μm was laminated on the outer surface of the barrier layer 51 via the outer adhesive layer 12 to form a protective layer 53.

[0417] This produced the laminate material L1 of Example 1. As shown in Table 4, the thickness of the thermal adhesive layer 6 of this laminate material L1 was 80 μm.

[0418] (2) Preparation of a simulated single cell As the simulated cells 2, three PP blocks each having a width of 20 mm, a length of 45 mm, and a height of 7 mm were fabricated.

[0419] (3) Fabrication of housing components As shown in FIGS. 4F and 4G, the laminate material L1 was cut to a width of 100 mm and a length of 250 mm, and the cut-out laminate material L1 was deep-drawn with the heat-sealing layer 6 (low-melting point layer 63) side facing inward to form a recessed portion 11 having a width of 27 mm, a length of 150 mm and a depth of 9 mm. The recessed portion 11 was then cut to a width (peripheral width) of 10 mm on the outside to form a flange portion 12, thereby producing a tray member 10A made of a skin sheet 10.

[0420] The laminate material L1 was cut into a metal laminate sheet having a width of 47 mm and a length of 170 mm, and a cover member 10B made of a rectangular skin sheet 10 was prepared.

[0421] (4) Tab lead fabrication An aluminum plate having a thickness of 0.2 mm, a width of 10 mm, and a length of 230 mm was prepared, and a film (coating film 82) made from maleic anhydride-modified polypropylene (Modic P502 manufactured by Mitsubishi Chemical) having a thickness of 0.1 mm, a width of 14 mm, and a length of 20 mm was adhered to both sides of the aluminum plate at a position 35 mm from both edges toward the center, to produce a tab lead 8.

[0422] (5) Fabrication of energy storage module samples Three mock cells 2 were housed in the recessed portion 11 of the tray member 10A, lined up in the length direction of the tray member 10A, and the tab lead 8 was arranged on the tray member 10A along the arrangement direction of the mock cells 2, passing through the center of the tray member 10A in the width direction. At this time, the covering films 82 on both sides of the tab lead 8 were arranged on the flange portions 12 of the tray member 10A, and both ends of the tab lead 8 were arranged so as to be drawn outward beyond the flange portions 12.

[0423] The cover member 10B was placed so as to cover the top of the tray member 10A, with the outer peripheral edge of the cover member 10B overlapping the flange portion 12 of the tray member 10A.

[0424] Next, flange portion 12 of tray member 10A and the outer peripheral edge portion of cover member 10B were sandwiched from above and below with a pressure seal mold and heated while applying pressure, thereby heat-sealing flange portion 12 of tray member 10A and the outer peripheral edge portion of cover member 10B to bond them together, and heat-sealing covering film 82 of tab lead 8 to tray member 10A and cover member 10B to bond them together. In this way, an electricity storage module sample of Example 4-1 was produced.

[0425] The heat sealing (thermal fusion treatment) conditions were 180°C x 0.3 MPa x 7 seconds.

[0426] <Example 4-2> As shown in Table 4, a laminate material L1 was used in which the total thickness of the thermal fusion layer 6 was 140 μm, the thicknesses of the low-melting point layers 61 and 63 on both the upper and lower sides of the thermal fusion layer 6 were 21 μm, and the thickness of the high-melting point layer 62 was 98 μm. The storage module sample of Example 4-2 was produced in the same manner as in Example 4-1 above.

[0427] <Example 4-3> As shown in Table 4, a laminate material L1 was used in which the total thickness of the heat-sealing layer 6 was 200 μm, the thicknesses of the low-melting point layers 61 and 63 on both the upper and lower sides of the heat-sealing layer 6 were 30 μm, and the thickness of the high-melting point layer 62 was 140 μm, and the sealing conditions during heat sealing were set to 190°C x 0.3 MPa x 7 seconds. Except for this, a storage module sample of Example 4-3 was produced in the same manner as in Example 4-1 above.

[0428] <Example 4-4> As shown in Table 4, a storage module sample of Example 4-4 was produced in the same manner as in Example 1 above, except that a laminate material L1 was used in which the total thickness of the thermal fusion layer 6 was 80 μm, the thicknesses of the low melting point layers 61 and 63 on both the upper and lower sides of the thermal fusion layer 6 were 20 μm, and the thickness of the high melting point layer 62 was 40 μm.

[0429] <Example 4-5> As shown in Table 4, an electricity storage module sample of Example 4-5 was produced in the same manner as in Example 4-1 above, except that an inner adhesive layer 72 to which an insulating filler was added was used.

[0430] <Examples 4-6> As shown in Table 4, a power storage module sample of Example 4-6 was produced in the same manner as in Example 4-1 above, except that the thermal adhesive layer 6 used a laminate material L1 made of CPP (melting point 121°C) with a thickness of 80 μm.

[0431] <Comparative Example 4-1> As shown in Table 4, a laminate material L1 was used in which the total thickness of the thermal fusion layer 6 was 40 μm, the thickness of the low melting point layers 61 and 63 on both the upper and lower sides of the thermal fusion layer 6 was 6 μm, and the thickness of the high melting point layer 62 was 28 μm. A storage module sample of Comparative Example 4-1 was produced in the same manner as in Example 4-1 above.

[0432] <Comparative Example 4-2> As shown in Table 4, a storage module sample of Comparative Example 4-2 was produced in the same manner as in Example 4-1 above, except that the heat-sealing layer 6 was made of a laminate material L1 composed of a 250 μm thick CPP (melting point 121°C) and the sealing conditions during heat sealing were set to 210°C x 0.3 MPa x 7 seconds.

[0433] <Insulation evaluation> For the energy storage module samples of Examples 4-1 to 4-6 and Comparative Examples 4-1 and 4-2, a current of 3 A at a voltage of 200 volts was passed from one end of the tab lead 8 to the other end using a current feeder for 3 hours, and then the current feeder was removed.

[0434] Thereafter, as shown in FIGS. 4F and 4G, protective layer 53 in the center of the outer surface of cover member 10B was peeled off in a rectangular shape to form barrier layer exposing recess 16 where barrier layer (aluminum foil) 51 was exposed.

[0435] Then, as shown in FIG. 4F, one lead terminal 31 of the tester 3 was brought into contact with one end of the tab lead 8, and the other lead terminal 31 was brought into contact with the barrier layer 51 in the barrier layer exposing recess 16, and the resistance value between the tab lead 8 and the barrier layer 51 was measured using a HIOKI3154 insulation resistance tester (detection limit 200 MΩ) to confirm whether or not electricity was flowing.

[0436] In measuring the resistance, three samples were tested for each example and comparative example. As a result, if no electrical conduction was confirmed in any of the three samples and all three samples had a resistance of 100 MΩ or more, the sample was evaluated as "Excellent." If all three samples had a resistance of 1 MΩ or more and even one sample had a resistance of less than 100 MΩ, the sample was evaluated as "Good." If electrical conduction was confirmed in any of the three samples or even one sample had a resistance of less than 1 MΩ, the sample was evaluated as "Failed." The results are also shown in Table 4.

[0437] <Thickness evaluation of thermal adhesive layer 6> After the above-mentioned insulation evaluation, the flange portion 12 of each sample was cut out along the broken line DL in Fig. 4G, and the cut surface of the cut flange portion was observed with a scanning electron microscope (SEM) to measure the thickness of the heat-sealable layer 6 after heat sealing. The results are also shown in Table 4.

[0438] As is clear from the evaluation results in Table 4, the samples (energy storage modules) of Examples 4-1 to 4-6, which incorporate the gist of the present invention, have excellent insulation properties and are thought to be able to reliably prevent short circuits and the like of the cells 2 housed therein.

[0439] In contrast, the samples of Comparative Examples 4-1 and 4-2, which deviate from the gist of the present invention, are found to have poor insulating properties. In Comparative Example 4-2, although the heat-sealing layer 6 before heat sealing was thick, the sealing conditions were stricter to ensure reliable heat sealing, and the heat-sealing layer 6 melted more than expected during heat sealing, resulting in a thinner thickness and insufficient insulating properties. [Industrial Applicability]

[0440] The housing for an electricity storage module of the present invention can be suitably used as a housing for a power module used when supplying large-capacity, large-current electric power.

[0441] This application claims priority to Japanese Patent Application No. 2020-136325 filed on August 12, 2020, Japanese Patent Application No. 2020-195899 filed on November 26, 2020, Japanese Patent Application No. 2020-212030 filed on December 22, 2020, and Japanese Patent Application No. 2020-214475 filed on December 24, 2020, the disclosures of which are incorporated herein by reference in their entirety.

[0442] It should be understood that the terms and expressions used herein are used for the purpose of explanation and not for limiting interpretation, and do not exclude any equivalents of the features shown and described herein, but also allow various modifications within the claimed scope of the present invention. [Explanation of symbols]

[0443] 1: Housing 10: Epidermal sheet 15: Battery compartment 16: Opening 2: Single cell (battery) 51: Barrier layer 52: Thermal adhesive layer (thermal fusion layer) 53:Protective layer 55: Battery fixing layer (thermal adhesive layer) L1: Laminate material

Claims

1. A housing for an electricity storage module includes a battery housing portion covered with a skin sheet, and the battery housing portion houses a plurality of unit cells, each unit cell having a battery element sealed in a case, the surface sheet is made of a laminate material including a barrier layer and a resin-made thermal adhesive layer laminated on the inner surface side of the barrier layer, The barrier layer is made of an aluminum foil selected from the group consisting of 1000 series, 3000 series, 5000 series, and 8000 series, and is tempered with an O material, and has an elongation of 15% to 35%, a Vickers hardness of 20 to 60, and a modulus of longitudinal elasticity of 60 kN / mm ２ ~80kN / mm ２ and the thickness of the barrier layer is set to 50 μm to 200 μm, The vehicle is constructed of two skin sheets, one above the other, and at least one of the skin sheets has a recessed portion and an outwardly protruding flange portion formed on the outer periphery of the recessed portion, the flange portions of the two skin sheets are thermally bonded to each other, and the battery accommodating portion is formed by the recessed portion; a heat-resistant resin protective layer is laminated on the outer surface of the barrier layer via an outer adhesive layer; the protective layer is composed of a single layer of polyester film or polyamide film, or a multi-layer of polyester film and polypropylene film, The thickness of the protective layer is 9 μm to 50 μm, the thermal adhesive layer is laminated to the barrier layer via an inner adhesive layer; The thermal adhesive layer is made of a polypropylene film, The thickness of the polypropylene film of the thermal adhesive layer is 30 μm to 100 μm, A housing for a storage module, in which a chemical conversion coating is formed as a base layer on both sides of the aluminum foil.

2. The housing for the electric storage module according to claim 1 , wherein an inner surface of the battery housing portion is configured so as to be able to be fixed to an outer surface of the unit cell.

3. 3. The housing for the electric storage module according to claim 1, wherein a battery fixing layer made of resin that can be thermally bonded to the outer surface of the unit cell is provided on the inner surface side of the barrier layer.

4. The housing for a storage module according to any one of claims 1 to 3, wherein the thermal adhesive layer is configured as a thermal fusion layer, the thermal fusion layer having insulating properties and a thickness set to 80 μm to 100 μm.

5. The housing for a storage module according to any one of claims 1 to 4, wherein the thermal adhesive layer of the laminate material is made of an unstretched film.

6. The housing for a storage module according to any one of claims 1 to 5, wherein the protective layer of the laminate material is made of a biaxially stretched film.

7. A housing according to any one of claims 1 to 6, A storage module characterized in that a plurality of batteries, each having a battery element sealed in a case, are housed in the battery housing portion of the housing.

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