Separator member, battery pack, and method for manufacturing same

Abstract

When a plurality of unit cells are housed in a case together with a partition member for partitioning the unit cells to constitute a battery pack, the partition member can be joined to an appropriate position on the surface of each unit cell to stack the two members, and the stacking position can be easily corrected. In a partition member for partitioning a plurality of unit cells stacked and housed in a battery pack, a contact part is provided on the surface of the partition member, preferably a contact part comprising a layer containing a water-soluble resin, and the partition member is configured so that the partition member can be attached to and detached from the surface of the unit cells by means of the contact part.

Description

Technical Field

[0001] The present invention relates to a partition member and a battery pack that are housed in a battery pack together with a plurality of single cells to partition the single cells. Background Art

[0002] In recent years, the use of secondary batteries as power sources for vehicles has increased dramatically, and research on increasing the energy density of secondary batteries has been progressing in order to increase the degree of freedom when installing them in limited spaces in vehicles and to extend the driving distance that can be traveled on a single charge.

[0003] Secondary batteries used as power sources for vehicles are generally used as assembled batteries composed of a plurality of cells (battery units). Therefore, when one of the cells constituting the assembled battery is damaged and generates heat, the adjacent cells are damaged due to the heat generated, and the damage may spread to the entire assembled battery in a chain reaction. In order to prevent such chain reactions between cells, a partition member is provided between the cells to cool the damaged cells or block heat conduction to the adjacent cells.

[0004] A module consisting of a battery pack in which many single cells are stacked at a high density is formed, and the module is installed in a housing of a battery pack while applying a restraining force to the module, thereby assembling a secondary battery for a vehicle requiring high output and large capacity. In the process of installing the module into the housing, the positions of the stacked single cells and the partition members are easily misaligned, and this operation process sometimes requires labor and time.

[0005] As a countermeasure for preventing misalignment between stacked cells and partition members, there is known a technique for integrally fixing a partition member made of a heat-insulating insulating sheet to the surfaces of cells sandwiching the partition member using double-sided adhesive tape (see, for example, Patent Document 1).

[0006] In addition, there is known a technique for preventing the positional displacement of the single cells by wrapping a wrap film around the stacked single cells to bundle the single cell group (see, for example, Patent Document 2).

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2021-61087

[0010] Patent Document 2: Japanese Patent Application No. 2022-523953 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] As described above, the module composed of the battery pack is composed of a plurality of battery cells and partition members stacked together, and is assembled by sequentially arranging the battery cells and partition members to form a row. If misalignment of the battery cells and partition members is found during the arrangement process, they are rearranged to a proper arrangement. Also, if misalignment occurs when the module is installed in the housing, the battery cells and partition members whose positions are deviated in the battery pack need to be rearranged to a proper arrangement.

[0013] In the case of using double-sided adhesive tape to bond the single cell and the partition member, the two members are fixed together with the help of the double-sided adhesive tape. However, when the positions of the single cell and the partition member are mistakenly misaligned and the two members are bonded together during the operation process of arranging the single cell and the partition member in a row, the operation of correcting the misalignment is extremely troublesome. That is, the adhesion of the double-sided adhesive tape is large, so it cannot be repeatedly pasted. It is necessary to tear off the bonded single cell and the partition member, and then paste the double-sided adhesive tape again to arrange the two members in an appropriate configuration and bond them. When tearing off the single cell and the partition member, the single cell or the partition member may also be deformed. When using double-sided adhesive tape, it is not possible to simply correct the overlapping position of the single cell and the partition member.

[0014] In addition, when a module is formed by bonding single cells and partition members using double-sided adhesive tape, or when a module is formed by winding a wrap film around a stacked single cell group, plastic materials are used. Therefore, in order to meet the requirements of life cycle assessment (LCA), when the battery group is disassembled as the secondary battery is discarded, the double-sided adhesive tape and the wrap film need to be separated, which increases the disposal cost.

[0015] The present invention is made in view of the problems in the prior art, and aims to make it possible to stack the two members by engaging the partitioning member with a suitable position on the surface of the single cell, and to prevent the stacked position from deviating, and to easily correct the deviated position, when a partitioning member for separating the single cells is housed in a casing together with a plurality of single cells to form a battery pack.

[0016] Solutions for solving problems

[0017] In order to solve the above-mentioned problems, the present invention includes the following aspects.

[0018] [1] A partition member, wherein:

[0019] The surface of the partition member is covered by an outer casing, and the outer casing has a contact portion on its surface that contacts the battery cell.

[0020] The contact portion can be switched between an ON state in which the contact portion exhibits close contact and an OFF state in which the contact portion does not exhibit close contact.

[0021] [2] A partition member comprising a porous body, water, and an outer body that accommodates the porous body and the water, wherein a contact portion that comes into close contact with an object to be contacted is provided on a surface of the outer body.

[0022] [3] The partition member according to [1] or [2], wherein a ratio of a peel strength in an adhesive ON state to a peel strength in an adhesive OFF state at the contact portion is 1.5 to 1000.

[0023] [4] The partition member according to any one of [1] to [3], wherein the adhesion of the contact portion is turned on by contact with water.

[0024] [5] The partition member according to any one of [1] to [4], wherein the adhesion of the contact portion is turned off due to drying.

[0025] [6] The partition member according to any one of [1] to [5], wherein the contact portion has a peel strength of 0.001 to 1.0 N / 10 mm.

[0026] [7] The partition member according to any one of [1] to [6], wherein the contact portion has a peel strength of 0.001 N / 10 mm or more and less than 0.010 N / 10 mm.

[0027] [8] The partition member according to any one of [1] to [7], wherein the contact portion contains a water-soluble resin.

[0028] [9] The partition member according to any one of [1] to [8], wherein the contact portion is provided so that a peel strength of the contact portion when the partition member is attached to a surface of a single cell is smaller than a bending strength of the partition member.

[0029]

[10] The partition member according to any one of [1] to [9], wherein the partition member has a contact portion on one surface.

[0030]

[11] The partition member according to any one of [1] to

[10] , wherein the contact portion is a layer formed on at least 50% of the area of ​​the partition member surface on which the contact portion is provided.

[0031]

[12] The partition member according to any one of [1] to

[10] , wherein the contact portion is a layer formed on at least 50% of the area of ​​the partition member surface on which the contact portion is provided, and the thickness of the layer is 0.1 to 20 μm.

[0032]

[13] A battery pack having a structure including a plurality of single cells and a plurality of partition members according to any one of [1] to

[12] arranged between the cells.

[0033]

[14] A battery pack having a structure in which single cells having the partition member described in any one of [1] to

[12] attached to one surface thereof are stacked with the partition member interposed therebetween.

[0034]

[15] A method for manufacturing a battery pack, comprising:

[0035] A step of attaching the partition member described in any one of [1] to

[12] to a surface of a single cell; and

[0036] A step of restraining a cell group formed by stacking the cell groups together with the partition members and the cell groups and accommodating the cell group in a case that supports the cell group.

[0037]

[16] The method for manufacturing a battery pack according to

[15] , further comprising the step of adjusting a mounting position of the partition member on the single battery.

[0038]

[17] The method for manufacturing a battery assembly according to

[15] or

[16] , wherein the method includes a step of bringing water into contact with a contact portion of the partition member.

[0039]

[18] A method, wherein the contact state of the partition member described in [1] to

[12] is turned on to bring the partition member described in [1] to

[12] into close contact with the surface of the cell.

[0040]

[19] A method, wherein the contact state of the partition members described in [1] to

[12] is set to an OFF state, and the partition members described in [1] to

[12] are attached to and detached from the surface of the single cell.

[0041] In addition, the present invention also includes the following aspects.

[0042] [1] A partition member that partitions a plurality of cells housed in a battery pack, wherein:

[0043] The partition member has a contact portion on its surface that contacts the cell, and can be attached to and detached from the surface of the cell via the contact portion.

[0044] [2] The partition member according to [1], wherein the contact portion can be switched between an ON state in which close contact is exhibited and an OFF state in which close contact is not exhibited.

[0045] [3] The partition member according to [2] above, wherein a ratio of a peel strength in an adhesive ON state to a peel strength in an adhesive OFF state at the contact portion is 1.5 to 1000.

[0046] [4] The partition member according to any one of [2] or [3], wherein the close contact of the contact portion is turned on by contact with water.

[0047] [5] The partition member according to any one of [2] to [4], wherein the adhesion of the contact portion is turned off due to drying.

[0048] [6] The partition member according to any one of [1] to [5], wherein the contact portion has a peel strength of 0.001 to 1.0 N / 10 mm.

[0049] [7] The partition member according to any one of [1] to [6], wherein the contact portion has a peel strength of 0.001 N / 10 mm or more and less than 0.010 N / 10 mm.

[0050] [8] The partition member according to any one of [1] to [7], wherein the contact portion contains a water-soluble resin.

[0051] [9] The partition member according to any one of [1] to [8], wherein the contact portion is provided so that a peel strength of the contact portion when the partition member is attached to a surface of a single cell is smaller than a bending strength of the partition member.

[0052]

[10] The partition member according to any one of [1] to [9], wherein the partition member has a contact portion on one surface.

[0053]

[11] The partition member according to any one of [1] to

[10] , wherein the contact portion is a layer formed on at least 50% of the area of ​​the partition member surface on which the contact portion is provided.

[0054]

[12] The partition member according to

[11] , wherein the thickness of the layer is 0.1 to 20 μm.

[0055]

[13] A battery pack having a structure including a plurality of single cells and a plurality of partition members according to any one of [1] to

[12] arranged between the cells.

[0056]

[14] A battery pack having a structure in which single cells having the partition member described in any one of [1] to

[12] attached to one surface thereof are stacked with the partition member interposed therebetween.

[0057]

[15] A method for manufacturing a battery pack, comprising:

[0058] A step of attaching the partition member described in any one of [1] to

[12] to a surface of a single cell; and

[0059] A step of restraining a cell group formed by stacking the cell groups together with the partition members and the cell groups and accommodating the cell group in a case that supports the cell group.

[0060]

[16] The method for manufacturing a battery pack according to

[15] , further comprising the step of adjusting a mounting position of the partition member on the single battery.

[0061]

[17] The method for manufacturing a battery assembly according to

[15] or

[16] , wherein the method includes a step of bringing water into contact with a contact portion of the partition member.

[0062]

[18] A method, wherein the contact state of the partition member described in [1] to

[12] is turned on to bring the partition member described in [1] to

[12] into close contact with the surface of the cell.

[0063]

[19] A method, wherein the contact state of the partition members described in [1] to

[12] is set to an OFF state, and the partition members described in [1] to

[12] are attached to and detached from the surface of the single cell.

[0064] As described above, one aspect of the present invention is a partition member whose surface is covered by an outer casing, and characterized in that the outer casing surface has a contact portion that can be switched from an OFF state in which adhesion is not exhibited to an ON state in which adhesion is exhibited.

[0065] Another aspect of the present invention is a partition member including a porous body, a liquid, and an outer body for storing the porous body and the liquid, wherein the outer body has a contact portion on a surface thereof that comes into close contact with a non-contact body.

[0066] The partition member can partition between each of a plurality of unit cells stacked or otherwise housed in the assembled battery, between a unit cell and battery components other than the unit cell, or between battery components other than the unit cell.

[0067] Furthermore, the partition member has a contact portion on its surface that contacts the single cell or a battery member other than the single cell, and can be attached to and detached from the surface of the single cell via the contact portion.

[0068] Furthermore, the contact portion is located outside the outer body relative to the porous body included in the partition member.

[0069] The "partition member can be installed and removed relative to the surface of the single cell by means of the contact portion" means that the partition member is installed on the surface of the single cell by clamping the contact portion provided on its surface, and can maintain the installed state, and when an external force is applied to separate the partition member installed on the single cell from the single cell, the installed partition member can be detached from the single cell without deforming or deteriorating the joint surface and the whole of the two components, the single cell and the partition member, and the detached partition member can be installed on the single cell again, and the above-mentioned installation and detachment operations relative to the single cell can be repeated.

[0070] In this way, when the partition member is stacked on the single cell, the partition member can be fixed to the surface of the single cell by engaging the contact portion provided on the surface of the partition member with the surface of the single cell. In addition, the partition member can be removed from the single cell by applying force between the two members in the direction in which the partition member is separated from the single cell.

[0071] The partition member is freely removable relative to the single cell. Therefore, when the partition member is mounted on the single cell and the single cell is arranged in a row to assemble a module composed of a single cell group, if a misalignment between the single cell and the partition member is found, the misalignment can be corrected by a simple operation of separating the partition member from the single cell that has temporarily deviated from the position and then re-mounting it in an appropriate position. Before the partition member is mounted in an appropriate position and fixed to the single cell, the partition member can be temporarily attached to the single cell by means of the contact portion.

[0072] The partition member can be mounted on the single cell by means of the contact portion provided on the surface thereof. Therefore, there is no need for plastic materials such as double-sided adhesive tape and wrapping film for bonding the two members. The partition member can be easily fixed to the single cell, and the operability and efficiency of assembling the module and the battery pack can be improved.

[0073] In the partition member of the above structure, the contact portion can be formed using a material having a property of being able to switch between an ON state in which close contact is exhibited and an OFF state in which close contact is not exhibited.

[0074] The "ON state showing adhesion" means a state in which the adhesive can be attached to the battery with a specific peel strength when attached to the battery, and the "OFF state not showing adhesion" means a state in which adhesion is different from that of the ON state. In addition, "can be switched to the ON state showing adhesion and the OFF state not showing adhesion" means that the ON state can be switched to the OFF state and the OFF state can be switched to the ON state by undergoing a specific operation.

[0075] In addition, "close contact" refers to the interface between common objects, that is, the state of a common surface, and means contact, adhesion, and bonding between a contact portion and an adherend.

[0076] The contact portion can be formed so that its adhesion becomes ON due to contact with water.

[0077] In addition, the adhesion of the contact portion can be formed so as to be in an OFF state due to drying.

[0078] The contact portion may be formed so that a ratio of a peel strength in an adhesive ON state to a peel strength in an adhesive OFF state is 1.5 to 1000.

[0079] In addition, the contact portion may be formed to have a peel strength of 0.001 to 0.10 N / 10 mm. Furthermore, the contact portion may be formed to have a peel strength of 0.001 N / 10 mm or more and less than 0.010 N / 10 mm.

[0080] The contact portion can be formed of a material containing a water-soluble resin.

[0081] In addition, the contact portion may be formed of a layer containing a water-soluble resin, and may further be formed of a layer containing polyvinyl alcohol.

[0082] In this case, the water-soluble resin can develop adhesion by forming an interface with the adherend surface in water during the curing process.

[0083] In the partition member having the above structure, the contact portion may be provided so that the peel strength of the contact portion when the partition member is attached to the surface of the cell is smaller than the bending strength of the partition member.

[0084] In addition, the contact portion may be provided on at least one surface of the partition member. The contact portion may be provided on both side surfaces of the partition member that are in contact with the single cells on the left and right sides.

[0085] The contact portion may be formed as a layer formed over at least 50% of the area of ​​the partition member surface on which the contact portion is provided.

[0086] In this case, the thickness of the layer is preferably set to 0.1 to 20 μm, and more preferably set to 0.1 to 10 μm.

[0087] From the perspective of effectively switching the thermal conductivity, when the average surface temperature of the partition member is 25° C., the thermal conductivity of the contact portion in the thickness direction is preferably 0.5 W / m·K or more and the thermal conductivity of the partition member is less than 0.25 W / m·K.

[0088] When the average surface temperature of the partition member is 25°C, the thermal conductivity of the contact portion in the thickness direction is preferably 0.5 W / m·K or more and the thermal resistance per unit area of ​​the partition member is less than 3.0×10―3 K / W.

[0089] The “surface average temperature” refers to the average temperature of any three points on the surface of the spacer that are in contact with the heat generating element.

[0090] Furthermore, the battery pack of the present invention is characterized by having a structure including a plurality of single cells and a plurality of partition members of the structure arranged between the cells.

[0091] In addition, the battery pack of the above structure is characterized in that the single cells having the partition member of the above structure attached to one surface thereof have a structure in which the single cells are stacked with the partition member interposed therebetween.

[0092] In addition, the method for manufacturing a battery pack of the present invention is characterized by comprising: a step of attaching the partition member having the above structure in contact with the surface of the single cell; and

[0093] A step of constraining a cell group formed by stacking the partition members and the cells and accommodating the cell group in a case that supports the cell group.

[0094] Furthermore, the manufacturing method is characterized by including a step of adjusting a mounting position of the partition member on the single cell.

[0095] Furthermore, the manufacturing method is characterized by including the step of installing, removing, and reinstalling the partition member in contact with the single cell.

[0096] Furthermore, the invention is characterized by including a step of bringing moisture into contact with a contact portion of the partition member before mounting on the single cell.

[0097] Furthermore, the invention is characterized by comprising a step of bringing moisture into contact with a contact portion of the partition member after mounting on the single cell.

[0098] In addition, the method for bonding the partition member includes placing a contact portion of the partition member in an ON state to bring the partition member into close contact with the surface of the cell.

[0099] In addition, the method of attaching and detaching the partition member includes placing the contact portion of the partition member in an OFF state and attaching and detaching the partition member to the surface of the cell.

[0100] Effects of the Invention

[0101] According to the partition member of the present invention, the partition member can be detachably constructed relative to the surface of the single cell by means of the contact portion. Therefore, the partition member can be joined and fixed at an appropriate position on the surface of the single cell to stack the two members, and when a deviation occurs in the overlapping position, after the partition member is temporarily separated from the single cell, the separated partition member can be fixed at an appropriate position to correct the misalignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 The schematic cross-sectional view (A) and the BB cross-sectional end view (B) show the structure of an example of the partition member of the present invention.

[0103] Figure 2 It is a diagram showing the structure of an example of a battery pack of the present invention.

[0104] Figure 3 Yes means Figure 2 Figure 1 is a diagram showing the side (A) and top (B) surfaces of a single cell used in a battery pack.

[0105] Figure 4 It is a diagram for explaining the process of fixing the partition member to the single cell.

[0106] Figure 5 It is a diagram for explaining the process of stacking a plurality of single cells to form a module of a single cell group. DETAILED DESCRIPTION

[0107] Hereinafter, preferred embodiments of the partition member and the battery pack of the present invention will be described. However, the embodiments described below are examples for embodying the technical concept of the present invention, and the present invention is not limited to the contents of the embodiments described below.

[0108] Figure 1 A partition member according to one embodiment of the present invention is shown.

[0109] The partition member 1 shown in the figure is configured by sealing a porous body 2 capable of retaining a liquid together with the liquid inside an outer body 3 .

[0110] Specifically, the partition member 1 has a structure in which the outer casing 3 has a sealing portion 32 formed by sealing the edges of multilayer sheets 31, 31 including a resin layer and a metal layer to each other in a strip shape, and a contact portion 4 is provided on one surface of the outer casing 3, and the partition member 1 can be attached to and detached from the surface of the unit cell 7 to be discussed later via the contact portion 4. The porous body 2 and the liquid may be sealed in the internal space surrounded by the sealing portion 32.

[0111] <Partitioning member>

[0112] like Figure 1 As shown, the partition member 1 is formed in a flat plate or sheet shape with an appropriate thickness. The partition member 1 is used to separate the cells constituting the assembled battery or the cells constituting the assembled battery from members other than the cells, such as the wall surface of a case that accommodates the cells and the partition member, in the thickness direction thereof.

[0113] The partition member in one aspect of the present invention can include a porous body, a liquid, and an outer body as a packaging material for storing these. The porous body generally has a low thermal conductivity. The porous body included in the partition member is immersed in the liquid, and its gaps are filled with the liquid, thereby increasing the thermal conductivity. Therefore, the thermal conductivity of the partition member can be higher than the thermal conductivity of the porous body itself.

[0114] In addition, the partition member can reduce its thermal conductivity by causing the liquid inside to disappear at a certain temperature.

[0115] From the viewpoint of increasing the rate of change of the thermal conductivity, the porous body is preferably a heat insulating material.

[0116] 〔Porous body〕

[0117] Porous bodies can retain liquids and usually have elasticity.

[0118] The elastic porous body shrinks or deforms in the thickness direction due to thermal expansion of the single cell. Figure 1 In the example shown, the porous body 2 is formed into a horizontally long rectangular flat plate or sheet. The porous body 2 is contained together with a liquid inside a rectangular flat plate or sheet-shaped outer body 3 larger than the porous body 2 and sealed inside the outer body 3 surrounded by a sealing portion 32.

[0119] The porous body preferably includes a powdered inorganic substance and a fibrous inorganic substance. In the present invention, "fibrous inorganic substance" means an inorganic substance having a shape in which the major diameter is more than 100 times the minor diameter, and "powdered inorganic substance" means an inorganic substance having a shape in which the major diameter is less than 100 times the minor diameter. In addition, especially in the case of a fibrous shape, "major diameter" means the fiber length, and "minor diameter" means the diameter of a cross section radially orthogonal to the major diameter.

[0120] The fibrous inorganic material is preferably at least one selected from the group consisting of paper, cotton sheet, polyimide fiber, aromatic polyamide fiber, polytetrafluoroethylene (PTFE) fiber, glass fiber, rock wool, ceramic fiber and biosoluble inorganic fiber, and among these, at least one selected from glass fiber, rock wool, ceramic fiber and biosoluble inorganic fiber is particularly preferred. Ceramic fiber is mainly composed of silica and alumina (silicon dioxide: alumina = 40:60 to 0:100), and specifically, silica·alumina fiber, mullite fiber, and alumina fiber can be used.

[0121] In addition, the powdered inorganic substance is preferably at least one selected from the group consisting of silica particles, alumina particles, calcium silicate, clay minerals, vermiculite, mica, cement, perlite, fumed silica and aerogel, and among these, at least one selected from silica particles, alumina particles, calcium silicate and vermiculite is particularly preferred. Among the types of calcium silicate, preferred are xonotlite, tobermorite, wollastonite, and whitish calcium zeolite, and whitish calcium zeolite is particularly preferred. Whitish calcium zeolite having a petal-like structure also maintains a porous structure when compressed and deformed, and therefore has excellent liquid retention. Clay minerals are mainly magnesium silicate (including talc and sepiolite), montmorillonite, and kaolinite.

[0122] The porous body containing the fibrous inorganic substance and the powdery inorganic substance can be selected from known porous bodies and used. For example, the porous body described in Japanese Patent Application Laid-Open No. 2003-202099 can be selected and used.

[0123] The density of the porous body is preferably 0.20 to 1.10 g / cm2 from the viewpoint of being lightweight and having excellent thermal insulation properties even at high temperatures. 3 If the density of the porous body is above the lower limit, the internal voids have more air layers, so it is preferred from the viewpoints of heat insulation and liquid retention. On the other hand, if the density of the porous body is below the upper limit, it is preferred from the viewpoint of reducing the deformation amount during compression. In addition, from these viewpoints, the density of the porous body is preferably 0.35 g / cm 3 More preferably, 0.55 g / cm 3 On the other hand, it is preferably 1.05 g / cm 3 Below, more preferably 1.00 g / cm 3 the following.

[0124] 〔liquid〕

[0125] The liquid held by the porous body contained in the outer casing has thermal conductivity and can efficiently transfer the heat generated by the single cell to the adjacent single cell. In addition, as the liquid, a liquid having a boiling point of 80°C or more and 250°C or less at normal pressure (1 atmosphere) is preferred, and a liquid having a boiling point of 100°C or more and 150°C or less at normal pressure is further preferred. In view of the large heat of vaporization and the fact that it can be obtained universally, water is particularly preferred as the liquid.

[0126] The liquid preferably includes at least one selected from the group consisting of water, alcohols, esters, ethers, ketones, hydrocarbons, fluorine compounds, and silicone oils, for example. These may be used alone or as a mixture of two or more.

[0127] Examples of alcohols that can be used as liquids include alcohols having 3 to 8 carbon atoms such as propanol, isopropanol, butanol, benzyl alcohol, and phenylethyl alcohol, and divalent or higher alcohols such as alkylene glycols such as ethylene glycol and propylene glycol. These may be used alone or as a mixture of two or more.

[0128] As esters that can be used in liquids, alkyl aliphatic carboxylates, alkyl carbonate diesters, alkyl oxalic acid diesters, and ethylene glycol fatty acid esters can be cited. As alkyl aliphatic carboxylates, lower alkyl formates such as methyl formate, n-butyl formate, and isobutyl formate can be cited; lower alkyl acetates such as n-propyl acetate, isopropyl acetate, n-butyl acetate, and isobutyl acetate; and lower alkyl aliphatic carboxylates such as lower alkyl propionates such as ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, and isobutyl propionate can be cited. As alkyl carbonate diesters, lower alkyl carbonate diesters such as dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and methyl ethyl carbonate can be cited. As alkyl oxalic acid diesters, lower alkyl oxalic acid diesters such as dimethyl oxalate and diethyl oxalate can be cited. As fatty acid esters of ethylene glycol, ethylene glycol acetate can be cited. These can be used alone or as a mixture of two or more.

[0129] Examples of ethers that can be used as a liquid include n-butyl ether, n-propyl ether, isoamyl ether, etc. These may be used alone or as a mixture of two or more.

[0130] Examples of ketones that can be used in the liquid include methyl ethyl ketone, diethyl ketone, etc. These may be used alone or as a mixture of two or more.

[0131] Examples of hydrocarbons that can be used as the liquid include heptane, octane, nonane, decane, toluene, xylene, etc. These may be used alone or as a mixture of two or more.

[0132] As fluorine compounds that can be used for liquids, there can be mentioned refrigerant 1,1,2,2,3,3,4-heptafluorocyclopentane (HFC-c447ef), 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorooctane (HFC-76-13sf), etc. These can be used alone or as a mixture of two or more.

[0133] Examples of silicone oils that can be used in the liquid include polymethylsiloxane, polymethylphenylsiloxane, cyclomethylsiloxane, and modified silicone oils such as silicone polyether copolymers. These may be used alone or as a mixture of two or more.

[0134] In addition, the liquid may also contain an antifreeze agent, a preservative, and a pH adjuster. These may be only one kind or may be used as a mixture of two or more kinds. The liquid may also contain additives such as a substance that imparts antifreeze properties (antifreeze agent), a preservative, and a pH adjuster. The substances contained in the liquid are not limited thereto and may be added as needed.

[0135] [Exterior body]

[0136] like Figure 1 As shown, the outer body 3 accommodates the porous body 2 holding the liquid in a sealed internal space surrounded by a sealing portion 32 formed by sealing the peripheral edges of two planar rectangular laminated sheets 31, 31 arranged opposite to each other in a strip shape.

[0137] The outer casing is flexible and can be deformed according to the expansion of the single cell. In addition, the outer casing can be restored to its original state when the single cell shrinks. As the outer casing, for example, a resin sheet, a resin film, etc. can be used. For example, by sandwiching the porous body between two relatively arranged or folded resin sheets or resin films, the peripheral edge of the outer casing where the two resin sheets or resin films are in contact is sealed by sealing means such as welding or thermal bonding, thereby sealing the porous body impregnated with a liquid.

[0138] As the outer casing, for example, an outer casing made of resin or metal can be used. From the viewpoint of heat resistance and high strength, a laminate formed by laminating metal foil and resin is preferred. As a laminate of metal and resin, a laminate or multilayer sheet having more than three layers including a protective resin layer, a metal layer, and a sealant resin layer is preferred. On the other hand, for the reason of not hindering the imparting of flexibility and the hygroscopic effect brought about by the inner packaging material, a laminate formed by laminating resin films to each other is preferred. As a laminate of resin films to each other, a combination of a protective resin layer and a sealant resin layer, or a combination of a barrier protective resin layer having barrier properties formed by vapor deposition of aluminum and silicon dioxide on the protective resin layer and a sealant resin layer, or a laminate or multilayer sheet having more than two layers including a barrier protective resin layer and a sealant resin layer is preferred.

[0139] Examples of the metal used for the metal foil and the metal layer include aluminum, copper, tin, nickel, stainless steel, lead, tin-lead alloy, bronze, silver, iridium, phosphor bronze, etc. Aluminum, copper, and nickel are particularly preferred, and aluminum is further preferred.

[0140] As the protective resin layer, there is no particular limitation, for example, polyolefin resins such as homopolymers or copolymers of ethylene, propylene, butene, etc.; amorphous polyolefin resins such as cyclic polyolefins; polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyamide resins such as nylon 6, nylon 66, nylon 12, and copolymerized nylon; ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polycarbonate resins, polyvinyl butyral resins, polyarylate resins, fluororesins, acrylic resins, biodegradable resins, etc. Among them, from the viewpoint of being able to impart heat resistance and mechanical strength as an outer body, polyamide resins such as nylon 6 and polyester resins such as polyethylene terephthalate are preferred. The protective resin layer may be only one layer or two or more layers may be stacked. In addition, when there are two or more layers, they may be selected from different resin layers or from the same resin layer.

[0141] The sealant resin layer can use at least one of a thermosetting resin and a thermoplastic resin, but a thermoplastic resin is particularly preferred. As the sealant resin layer, for example, polyolefin resins such as homopolymers or copolymers of ethylene, propylene, butene, etc.; amorphous polyolefin resins such as cyclic polyolefins; polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyvinyl butyral resins, acrylic resins, biodegradable resins, etc. Among them, from the perspective of the melting characteristics at low temperatures for obtaining the function of releasing the liquid inside the outer body to the outside during abnormal heating, it is preferred to select at least one of polyolefin resins such as high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLPDE), and polypropylene resin. Moreover, from the perspective of long-term storage in the temperature range generally used as a separator of a battery pack and the perspective of versatility, polypropylene resin is more preferred, and non-stretched polypropylene resin is particularly preferred.

[0142] The thickness of the protective resin layer is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more from the viewpoint of providing mechanical strength. To ensure flexibility, it is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 30 μm or less.

[0143] The thickness of the metal layer is not particularly limited, but from the viewpoint of ensuring moisture permeability and suppressing the generation of pinholes, it is preferably 5 μm or more, more preferably 8 μm or more, and more preferably 12 μm or more. In addition, from the viewpoint of ensuring flexibility, it is preferably 50 μm or less, more preferably 35 μm or less, and further preferably 20 μm or less.

[0144] The thickness of the sealant resin layer is not particularly limited, but from the viewpoint of ensuring sealing performance, it is preferably 10 μm or more, more preferably 20 μm or more, and further preferably 30 μm or more. In addition, in order to ensure flexibility, it is preferably 120 μm or less, more preferably 100 μm or less, and further preferably 80 μm or less.

[0145] The thickness of the outer body is not particularly limited, but considering the thickness of each layer, it is preferably 30 μm or more, more preferably 45 μm or more, and further preferably 65 μm or more from the viewpoint of mechanical strength. In addition, in order to ensure flexibility, it is preferably 280 μm or less, more preferably 210 μm or less, and further preferably 150 μm or less.

[0146] In addition, for the outer body, the peripheral portions of the two outer bodies are joined into a ring shape by a sealing means such as welding or thermal bonding, so that the liquid and the porous body are sealed in the outer body. Alternatively, one outer body may be bent and the peripheral portions may be joined by the sealing means to seal the liquid and the porous body. The outer body is preferably flexible, i.e., elastic, but may not be flexible.

[0147] From the viewpoint that the temperature when the hole is generated is high enough, it is preferred that the internal air pressure of the outer body is lower than the external air pressure. Therefore, it is particularly preferred to perform vacuum sealing when the outer body is sealed. In addition, the temperature when the hole is generated can also be controlled by adjusting the internal air pressure.

[0148] [Contact part]

[0149] like Figure 1 As shown, the contact portion 4 is provided on the surface of the outer casing 3 on one side of the partition member 1 formed in a flat plate or sheet shape, and the partition member 1 can be attached to and detached from the surface of the battery pack relative to the surface of the single cell via the contact portion 4 .

[0150] The contact portion 4 can be formed using a material that exhibits adhesion when in contact with water, such as a water-soluble resin.

[0151] Such a material is preferred because it exhibits non-adhesion in a dried state, but exhibits adhesion by re-dissolving or swelling the water-soluble resin when water is added.

[0152] The contact portion 4 may be formed of a material having a peel strength of 0.001 to 0.1 N / 10 mm as measured in accordance with JIS Z0237 when the contact portion 4 is in contact with water and left to stand for 5 minutes or more with a load applied so that an adherend is in contact with the contact portion.

[0153] The peel strength is preferably a peel strength with respect to any adherend, and more preferably a peel strength with respect to the surface of the outer casing of the cell.

[0154] From the viewpoint of facilitating positioning due to lack of close contact with the adherend, the peel strength in the ON state is preferably 0.01 to 0.8 N / 10 mm, more preferably 0.01 to 0.5 N / 10 mm.

[0155] In addition, the peel strength in the OFF state can be obtained by performing the measurement without contact between the adherend and the contact portion and drying for 3 days or more in an environment at 23°C and a dew point of -80°C. From the viewpoint of preventing the films from sticking together during film transportation, the peel strength is preferably 0.001 N / 10 mm or more and less than 0.01 N / 10 mm.

[0156] The contact portion 4 can be formed of a material containing a water-soluble resin.

[0157] As the water-soluble resin, there is no particular limitation as long as it has the function of a rewetting adhesive, and various starches such as oxidized starch and etherified starch, animal glue, gum arabic, gum tragacanth, dextrin, polyvinyl alcohol, vinyl acetate resin, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether and other polyvinyl ethers, polyvinyl pyrrolidone, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, cellulose derivatives such as viscose, polyethylene glycol, polyethylene oxide, casein, gelatin, sodium alginate, etc. Among them, polyvinyl alcohol is particularly preferred from the viewpoint of adhesiveness.

[0158] The saponification degree of the polyvinyl alcohol resin used in the present invention (measured in accordance with JIS K 6726:1994) is usually 60 to 100 mol%. From the viewpoint of improving adhesion, the saponification degree is preferably 80 to 99 mol%, more preferably 80 to 90 mol%. Whether the saponification degree is low or high, the water solubility tends to decrease and the adhesive strength tends to decrease.

[0159] The average degree of polymerization (measured in accordance with JIS K 6726:1994) of the polyvinyl alcohol-based resin used in the present invention is usually 100 to 4000. From the viewpoint of improving adhesion, it is preferably 200 to 3000, more preferably 300 to 2800, and further preferably 500 to 2500. If the average degree of polymerization is too small, the adhesive force tends to decrease, and if it is too large, the viscosity of the aqueous solution during film formation tends to be high and the productivity tends to decrease.

[0160] In addition, the polymerization degree of the polyvinyl alcohol resin can generally be expressed as a water-soluble viscosity. From the viewpoint of improving adhesion, the viscosity of a 4 wt% aqueous solution of the polyvinyl alcohol resin of the present invention at 20° C. is preferably 3 to 70 mPa·s, more preferably 5 to 60 mPa·s, and particularly preferably 10 to 50 mPa·s. If the viscosity is too low, there is a tendency for the adhesive force to decrease, and if it is too high, there is a tendency for the aqueous solution viscosity to be high during film formation and for productivity to decrease.

[0161] In addition, when the polyvinyl alcohol resin is a modified polyvinyl alcohol resin, the modification rate in the modified polyvinyl alcohol resin, that is, the content of structural units derived from various monomers in the copolymer, or functional groups introduced by post-reaction, varies greatly depending on the type of functional groups. Therefore, it cannot be generalized, but is usually 0.1 to 20 mol%.

[0162] By using the above-mentioned material, the contact portion 4 can have such close adhesion that the partition member can be fixed to the surface of the single cell.

[0163] In the present invention, a filler or the like may be further contained as necessary.

[0164] In terms of anti-blocking properties, it is preferred to contain fillers, and specific examples include inorganic fillers and organic fillers, of which organic fillers are preferred. In addition, the average particle size is preferably 0.1 to 20 μm, and further preferably 0.5 to 15 μm. In addition, the above average particle size can be measured, for example, by a laser diffraction particle size distribution measuring device.

[0165] From the viewpoint of improving the blocking effect, the average particle size of the inorganic filler is preferably 1 to 10 μm. If the average particle size is too small, it is difficult to obtain the anti-blocking effect, and if it is too large, there is a tendency that when the water-soluble film is stretched during the forming process, pinholes are formed or the appearance is reduced.

[0166] Specific examples of the inorganic filler include talc, clay, silica, diatomaceous earth, kaolin, mica, asbestos, gypsum, graphite, glass balloons, glass beads, calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite, calcium carbonate, whisker-shaped calcium carbonate, magnesium carbonate, dawsonite, dolomite, potassium titanate, carbon black, glass fiber, alumina fiber, boron fiber, processed mineral fiber, carbon fiber, carbon hollow sphere, bentonite, montmorillonite, copper powder, sodium sulfate, potassium sulfate, zinc sulfate, copper sulfate, iron sulfate, magnesium sulfate, aluminum sulfate, potassium aluminum sulfate, ammonium nitrate, sodium nitrate, potassium nitrate, aluminum nitrate, ammonium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium phosphate, potassium chromate, etc. These can be used alone or in combination of two or more.

[0167] From the viewpoint of improving the blocking effect, the average particle size of the organic filler is preferably 0.5 to 20 μm, more preferably 0.5 to 10 μm, particularly preferably 0.5 to 7 μm, and particularly preferably 0.5 to 5 μm. If the average particle size is too small, it is difficult to obtain the anti-blocking effect, and if it is too large, there is a tendency that when the water-soluble film is stretched during the forming process, pinholes are formed.

[0168] As the organic filler, for example, in addition to starch, melamine resin, polymethyl methacrylate resin, polystyrene resin, biodegradable resins such as polylactic acid, etc. can also be listed. Among them, as the organic filler, biodegradable resins such as polymethyl methacrylate resin, polystyrene resin, starch, etc. are particularly preferably used. These can be used alone, or two or more can be used together.

[0169] As the starch, for example, raw starch (corn starch, potato starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, corn starch, rice starch, bean starch, kudzu starch, bracken starch, lotus root starch, water chestnut starch, etc.), physically modified starch (α-starch, graded straight chain starch, wet heat treated starch, etc.), enzyme modified starch (hydrolyzed dextrin, enzyme decomposed dextrin, straight chain starch, etc.), chemically decomposed modified starch (acid treated starch, hypochlorous acid oxidized starch, dialdehyde starch, etc.), chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, cross-linked starch, etc.), etc. can be cited. Among them, from the perspective of ease of acquisition and economy, raw starch, especially corn starch and rice starch, is preferably used. These can be used alone, or two or more can be used together.

[0170] From the viewpoint of improving the blocking effect, the content of the filler in the case of containing the filler is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and particularly preferably 2.5 to 20 parts by mass relative to 100 parts by mass of the polyvinyl alcohol resin. If the content is too small, there is a tendency for the blocking resistance to decrease, and if it is too large, there is a tendency that when the water-soluble film is stretched during the molding process, pinholes are formed.

[0171] In addition, it is preferable that the peel strength of the contact portion 4 be set to be smaller than the bending strength of the partition member. The peel strength can be measured by the method described in JIS K 6854.

[0172] As long as the peel strength of the contact portion 4 is smaller than the bending strength of the partition member, the partition member can be separated without being deformed when separated from the single cell.

[0173] like Figure 1 As shown, the contact portion 4 may be provided on the surface of the laminated sheet 31 on one side surface of the partition member 1 or on the surface of the outer casing 31 on both left and right sides of the partition member 1 .

[0174] Furthermore, the contact portion 4 can be a layer formed on at least 50% of the area of ​​the surface of the laminated sheet 31 of the partition member 1 on which the contact portion is provided.

[0175] When the layer is formed in an area of ​​50% or more, uneven adhesion to an adherend due to deflection of the film having the contact portion can be alleviated, and therefore, it is preferred from the viewpoint of ensuring sufficient adhesion.

[0176] The thickness of the layer forming the contact portion 4 is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 1.0 to 10 μm.

[0177] In order to prevent the adhesion of the films during film transportation, the thickness of the layer is preferably above the lower limit, and on the other hand, in order to fully ensure the adhesion with the adherend, the thickness of the layer is preferably below the upper limit. If it deviates from the above range, the coating at the contact part may fall off or the thickness may be uneven.

[0178] The partition member 1 of the above structure is formed by sealing the peripheral edges of two planar rectangular outer bodies (laminated sheets) 31, 31 facing each other having the contact portion 4 in a strip shape. The porous body 2 holding the liquid can be sealed in the sealed internal space surrounded by the sealing portion 32.

[0179] Alternatively, the contact portion 4 may be provided after the peripheral edge portions of the outer casing not having the contact portion 4 are sealed together in a strip shape.

[0180] When the partition member 1 constructed in this way is stacked on a single cell, the contact portion 4 provided on the surface of the partition member 1 engages with the surface of the single cell, thereby enabling the partition member 1 to be fixed to the surface of the single cell. In addition, by applying force between the two members in the direction in which the partition member 1 is separated from the single cell, the partition member 1 can be removed from the single cell.

[0181] The partition member 1 can be freely installed and removed relative to the single cell. Therefore, when assembling a module composed of a single cell group, when a misalignment between the single cell and the partition member 1 is found, the misalignment can be corrected by a simple operation of separating the partition member 1 from the single cell that has temporarily deviated from its position and then installing it again in the appropriate position, thereby improving the operability and efficiency of assembling the module and the battery group.

[0182] In addition, the partition member 1 installed on the single cell is heated by the single cell and the internal pressure of the partition member 1 increases, which causes the partition member 1 to open and spray the internal liquid to the outside, so that the thermal resistance of the porous body 2 sealed inside the partition member 1 is switched to a higher thermal resistance. As a result, the single cell that is in contact with the partition member 1 and has an abnormal temperature rise can be cooled, while the heat conduction to the adjacent single cell is suppressed.

[0183] <Battery pack>

[0184] Figure 2 An example of the structure of a battery pack in which the single cells are divided by the partition member 1 having the above structure is shown. Figure 3 An example of the structure of a single cell constituting a battery pack is shown.

[0185] The cells 7 used in the battery pack 6 are generally so-called square cells or pouch cells, and are in the shape of a rectangular parallelepiped having appropriate thickness, width, and height, and are provided with electrode terminals 71 , 71 on the upper surface and side surfaces thereof.

[0186] The cell 7 is, for example, a lithium ion secondary battery having a positive electrode and a negative electrode capable of absorbing and releasing lithium ions, and an electrolyte. In addition to the lithium ion secondary battery, secondary batteries such as lithium ion all-solid batteries, lithium polymer batteries, lithium metal batteries, lithium sulfur batteries, lithium air batteries, all-resin batteries, sodium sulfur batteries, nickel hydrogen batteries, nickel cadmium batteries, and lead storage batteries can also be used.

[0187] The assembled battery 6 is composed of a plurality of cells 7 stacked and stored in a housing 6 having a bottom wall 61, four side walls 62, and a cover member (not shown). The cells 7 are separated by a partition member 1 having the above structure, and adjacent cells 7 are separated in the thickness direction of the partition member 1. The positive and negative electrode terminals 71, 71 of adjacent cells 7 are connected in series or in parallel, or in a combination of series and parallel, by a bus bar (not shown), so that the assembled battery 5 outputs a predetermined power.

[0188] A large battery assembly can also be formed by electrically connecting a plurality of battery assemblies in series or in parallel, or in a combination of series and parallel. In this case, a partition member having the same structure as the partition member 1 can be arranged between the battery assemblies inside the large battery assembly.

[0189] The battery pack 6 can be manufactured through the following steps: Figure 4 As shown, the process of installing the partition member 1 by contacting the partition member 1 with the surface of the single cell 7 by means of the contact portion 4 of the partition member 1; Figure 5As shown, there are steps of stacking the cells 7 to which the partition members 1 are attached, sandwiching the partition members 1, and restraining the stacked cell group and accommodating the stacked cell group in the case 6 that supports the cell group.

[0190] The manufacturing process may also include the following steps: a step of adjusting the installation position of the partition member 1 to the single cell 7; a step of bringing moisture into contact with a layer containing a water-soluble resin in a case where the contact portion 4 of the partition member 6 is provided with the layer to achieve tight adhesion; or a step of installing the partition member 1 to the single cell 7.

[0191] The partition member 1 is preferably located outside the single cell 7 and accommodated inside the battery pack 6. At this time, the area ratio of the partition member 1 to the area of ​​the contact surface of the adjacent single cell 7 and the partition member 1 (area of ​​the partition member / area of ​​the contact surface of the single cell and the partition member) is preferably 0.5 to 1.1, more preferably 0.8 to 1.05, and particularly preferably 0.9 to 1.0. Within this range, there are the following tendencies: heat transfer between single cells is promoted at room temperature; when the single cell is abnormally heated, the sealing part is heated higher and is easy to rupture; when the single cell is abnormally heated, a greater internal pressure is applied to the sealing part, which is easy to rupture; when the single cell is abnormally heated, the single cells are better insulated.

[0192] In order to prevent the sealing portion from heating up and becoming easily broken when the single cell heats up abnormally, it is desirable to set the width of the sealing portion in such a way that the sealing portion of the partition member and the contact surface of the adjacent single cell with the partition member overlap, and the width of the sealing portion is set to a size that is such that all portions inside the inner edge of the sealing portion are located inside the contact surface between the adjacent single cell and the partition member.

[0193] The battery pack is, for example, a battery pack that can be applied to electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), electric heavy equipment, electric motorcycles, electric assisted bicycles, ships, aircraft, trains, uninterruptible power supplies (UPS), household power storage systems, power system stabilization battery systems using renewable energy such as wind power / sunlight / tidal / geothermal energy, etc. However, the battery pack can also be used as a power source for supplying power to equipment other than the above-mentioned EVs, etc.

[0194] Example

[0195] In the partition member of the present invention, preferred forms of the contact portion will be described in detail based on examples, but the present invention is not limited to these examples.

[0196] (Sample production)

[0197] The sample partition member was made using an outer body composed of an aluminum laminate film (a 15 μm thick biaxially stretched polyethylene terephthalate film (outside) as a protective resin layer, a 12 μm thick aluminum layer as a metal layer, a 30 μm thick linear low-density polyethylene (LLDPE) film (inside) as a sealant resin layer, and a total thickness of 67 μm including a 5 μm thick polyurethane adhesive layer between each layer).

[0198] The circumferential dimensions of the partition member of the sample are set to 145mm×90mm, and the dimensions of the built-in body (vermiculite sheet; thickness 1mm) sealed inside and composed of a porous sheet are set to 112mm×58mm. Five sheets of the built-in body are stacked and sealed with a small amount of water, so that the thickness of the internal space configuration portion becomes 5mm and the weight of the entire sample becomes 20g.

[0199] A test was conducted to determine the degree of adhesion of the sample partition members produced under the above conditions when the partition members were attached to the surface of the cell.

[0200] In the test, water was applied as evenly as possible to one side of the partition member using a sponge, and the side with the water was pressed against an aluminum plate serving as a single cell, which was then flipped 180 degrees (so that the pressed surface was on top and the partition member was on the bottom), and the time required for the drop was measured to evaluate the adhesion. The amount of water applied using the sponge was set to 10 mg.

[0201] (Example 1)

[0202] An aqueous solution of polyvinyl alcohol (product name; GOHSENOLGH-17R, manufactured by Mitsubishi Chemical Corporation) was applied to one surface of the partition member of the prepared sample and dried in a dryer at 80°C for 5 minutes to form a contact portion consisting of an adhesion layer with a thickness of 1 μm.

[0203] The test was performed by applying 10 mg of water to the contact portion of the partition member. The results are shown in Table 1.

[0204] (Example 2)

[0205] A partition member was produced under the same conditions as in Example 1 except that the thickness of the adhesion layer was 3 μm, and the same test was performed. The results are shown in Table 1.

[0206] (Example 3)

[0207] A partition member was produced under the same conditions as in Example 1 except that the thickness of the adhesion layer was 0.5 μm, and the same test was performed. The results are shown in Table 1.

[0208] (Example 4)

[0209] A partition member was produced under the same conditions as in Example 1 except that the thickness of the adhesion layer was 1 μm, and 5 mg of water was applied to the contact portion to perform the same test.

[0210] [Table 1]

[0211] Thickness of the sealing layer (μm) Water coating amount (mg) Sealing time (N=3 average) Example 1 1 10 More than 1 day Example 2 3 10 More than 1 day Example 3 0.5 10 1 hour Example 4 1 5 More than 1 day

[0212] The test results above confirm that the adhesion can be controlled by adjusting the thickness of the layer at the contact portion and the amount of water in contact therewith. The adhesion of the adhesion layer of the partition member of the above-mentioned embodiment changes from the ON state to the OFF state.

[0213] The above-described structures of the partition member and the battery pack of the present invention are merely examples, and can be appropriately modified based on design requirements and the like without departing from the spirit of the present invention.

[0214] In addition, in this specification, when it is expressed as "X to Y" or "X~Y" (X, Y are arbitrary numbers), unless otherwise specified, it means "more than X and less than Y", and also means "preferably larger than X" and "preferably smaller than Y".

[0215] Furthermore, when expressed as “X or more” (X is an arbitrary number), unless otherwise specified, it includes the meaning of “preferably greater than X”, and when expressed as “Y or less” (Y is an arbitrary number), unless otherwise specified, it includes the meaning of “preferably less than Y”.

[0216] Description of Reference Numerals

[0217] 1. Partition member; 2. Porous body; 3. Outer casing; 31. Multilayer sheet; 32. Sealing portion; 4. Contact portion; 5. Battery pack; 6. Shell; 61. Bottom wall portion; 62. Side wall portion; 7. Single cell; 71. Electrode terminal.

Claims

1. A partition member, wherein: The surface of the partition member is covered by an outer casing, and the outer casing has a contact portion on its surface that contacts the battery cell. The contact portion can be switched between an ON state in which the contact portion exhibits close contact and an OFF state in which the contact portion does not exhibit close contact.

2. A partition member, wherein: The partition member includes a porous body, water, and an outer body that accommodates the porous body and the water, and a contact portion that comes into close contact with an object to be contacted is provided on a surface of the outer body.

3. The partition member according to claim 1 or 2, wherein: The ratio of the peel strength in the adhesive ON state to the peel strength in the adhesive OFF state of the contact portion is 1.5 to 1000.

4. The partition member according to claim 1 or 2, wherein: The adhesion of the contact portion becomes ON due to contact with water.

5. The partition member according to claim 1 or 2, wherein: The adhesion of the contact portion becomes OFF due to drying.

6. The partition member according to claim 1 or 2, wherein: The contact portion has a peel strength of 0.001 to 1.0 N / 10 mm.

7. The partition member according to claim 1 or 2, wherein: The contact portion contains a water-soluble resin.

8. The partition member according to claim 1 or 2, wherein: The contact portion is provided so that the peel strength of the contact portion when the partition member is attached to the surface of the single cell is smaller than the bending strength of the partition member.

9. The partition member according to claim 1 or 2, wherein: The partition member has a contact portion on one surface.

10. The partition member according to claim 1 or 2, wherein: The contact portion is a layer formed over at least 50% of the area of ​​the surface of the partition member on which the contact portion is provided.

11. The partition member according to claim 1 or 2, wherein: The contact portion is a layer formed on at least 50% of the area of ​​the surface of the partition member provided with the contact portion, and the thickness of the layer is 0.1 to 20 μm.

12. A battery pack, wherein: The battery pack has a structure including a plurality of single cells and a plurality of partition members according to any one of claims 1 to 11 disposed between the cells.

13. A battery pack, wherein: The battery pack has a structure in which single cells, each of which has the partition member according to any one of claims 1 to 11 attached to one surface thereof, are stacked with the partition member interposed therebetween.

14. A method for manufacturing a battery pack, wherein: The manufacturing method of the battery pack includes: A step of attaching the partition member according to any one of claims 1 to 11 so as to contact and attach the partition member to a surface of a single cell; and A step of restraining a cell group formed by stacking the cell groups together with the partition members and the cell groups and accommodating the cell group in a case that supports the cell group.

15. The method for manufacturing a battery pack according to claim 14, wherein: The method for manufacturing a battery pack includes a step of bringing moisture into contact with a contact portion of a partition member.

Images