Partition member, battery pack, and manufacturing method thereof

Abstract

According to the present invention, if a battery pack is configured by having a plurality of unit cells contained in a case together with partition members that partition the unit cells from each other, the partition members are bonded to appropriate positions of the unit cell surfaces so that the members can be stacked upon each other, and the stacked positions can be easily corrected.　With respect to the partition members that partition the plurality of unit cells from each other, the unit cells being stacked upon each other and contained in the battery pack, the surface of each partition member is provided with a contact part which is formed of a layer that preferably contains a water-soluble resin, and each partition member can be attached to and detached from the surface of a unit cell by the intermediary of this contact part.　

Description

[Technical Field]

[0001] The present invention relates to a partition member that is housed together with a plurality of unit cells in a battery pack and separates the unit cells, and to the battery pack. [Background technology]

[0002] In recent years, the use of secondary batteries as power sources for vehicles and other devices has been rapidly increasing. Research is underway to increase the energy density of secondary batteries in order to improve flexibility in installing them in limited spaces such as vehicles and to extend the driving range per charge.

[0003] Secondary batteries used as vehicle power sources are generally used as assembled batteries consisting of multiple cells (battery cells), so if one of the cells in the assembled battery is damaged and generates heat, the heat may damage adjacent cells, causing a chain reaction of damage to the entire assembled battery.To prevent this chain reaction of damage between cells, partition members are typically installed between the cells to cool the damaged cell or block heat conduction to adjacent cells.

[0004] The assembly of vehicle secondary batteries, which require high output and large capacity, is carried out by forming a module consisting of a group of cells in which a large number of cells are stacked at a high density, and then assembling this module into a battery pack housing while applying a restraining force to the module. During the process of assembling this module into the housing, the stacked cells and the partition members are likely to become misaligned, making this process time-consuming.

[0005] As a measure to prevent misalignment between stacked cells and partition members, a technique is known in which a partition member made of an insulating sheet with heat-insulating properties is attached to the surfaces of the cells on both sides of the partition member with double-sided adhesive tape to secure them together (see, for example, Patent Document 1). Furthermore, there is known a technique for preventing displacement of the cells by bundling a group of cells by wrapping a wrap film around the stacked cells (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-61087 [Patent Document 2] Special Publication No. 2022-523953 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, a module consisting of a group of cells is constructed by stacking and arranging a large number of cells and partition members, and is assembled by sequentially arranging the cells and partition members in a row. If any misalignment of the cells or partition members is found during the arranging process, they must be rearranged to the correct position. Also, if any misalignment occurs when the module is installed inside the housing, the misaligned cells or partition members within the group of cells must be rearranged to the correct position.

[0008] When the cells and the partition member are attached with double-sided adhesive tape, the two members are fixed together via the double-sided adhesive tape. However, if the cells and the partition member are accidentally misaligned during the process of arranging them in a row, correcting the misalignment is extremely troublesome. Because the double-sided adhesive tape has a strong adhesive force, it cannot be repeatedly attached. It is necessary to peel off the attached cells and the partition member, reapply the double-sided adhesive tape, and then align and reattach the two members in the correct position. When peeling off the cells and the partition member, there is also a risk of deformation of the cells or the partition member. Using double-sided adhesive tape makes it difficult to easily correct the overlapping position of the cells and the partition member.

[0009] Furthermore, whether a module is constructed by attaching cells and partition members with double-sided adhesive tape or by wrapping plastic wrap around a group of stacked cells, plastic materials are used. Therefore, in accordance with requirements for life cycle assessment (LCA), when dismantling the assembled battery in conjunction with the disposal of secondary batteries, the double-sided adhesive tape and plastic wrap must be separated, resulting in the problem of increased disposal costs.

[0010] In view of the problems with conventional technology, the present invention aims to provide a battery pack that, when a battery pack is constructed by storing a plurality of single cells and partition members that separate the individual cells in a housing, can be stacked and arranged by joining the partition members to the appropriate positions on the surfaces of the single cells, and the stacked positions are unlikely to shift, while any shifted positions can be easily corrected. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention includes the following aspects. [1] The surface is covered with an exterior body, and the exterior body has a contact portion on its surface that comes into contact with the unit cell, The partition member allows the contact portion to transition between an ON state in which contact is established and an OFF state in which contact is not established. [2] A partition member comprising a porous body, water, and an exterior body that accommodates these, and a contact portion that comes into close contact with a contacted body is provided on the surface of the exterior body. [3] The partition member according to [1] or [2], wherein the ratio of the peel strength of the contact portion in the on-state of adhesion to that in the off-state of adhesion is 1.5 to 1000. [4] The partition member according to any one of [1] to [3], wherein the adhesiveness of the contact portion is turned on by contact with water. [5] The partition member according to any one of [1] to [4], wherein the adhesiveness of the contact portion is turned off by drying. [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. [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. [8] The partition member according to any one of [1] to [7], wherein the contact portion contains a water-soluble resin. [9] A partition member according to any one of [1] to [8], 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 battery is smaller than the bending strength of the partition member.

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

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

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

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

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

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

[12] arranged between the individual cells.

[14] A battery pack having a configuration in which unit cells, each having the partition member according to any one of [1] to

[12] attached to the surface of one side thereof, are stacked with the partition member sandwiched between them.

[15] A step of attaching the partition member according to any one of [1] to

[12] to the surface of a single cell in contact with the surface of the single cell; and housing the battery group, which is formed by stacking the partition member and the battery cells, in a housing that supports the battery group while restraining the battery group.

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

[15] , further comprising the step of adjusting the attachment position of the partition member to the unit cells.

[17] The method for manufacturing the battery pack according to

[15] or

[16] , further comprising a step of bringing moisture into contact with the contact portion of the partition member.

[18] A method of bringing the contact state of the partition member according to any one of [1] to

[12] into an on state and bringing it into close contact with the surface of the unit cell.

[19] A method for detaching the partition member according to any one of [1] to

[12] above from the surface of a cell by turning the contact state of the partition member to an OFF state.

[0012] The present invention also includes the following aspects. [1] A partition member that separates each of a plurality of cells housed in a battery pack, The partition member has a contact portion on its surface that comes into contact with the unit cells, and is detachable from the surface of the unit cells via the contact portion. [2] The partition member according to [1], wherein the contact portion can transition between an ON state in which adhesion is present and an OFF state in which adhesion is not present. [3] The partition member according to [2] above, wherein the ratio of the peel strength of the contact portion in the on-state of adhesion to that in the off-state of adhesion is 1.5 to 1000. [4] The partition member according to [2] or [3], wherein the adhesiveness of the contact portion is turned on by contact with water. [5] The partition member according to any one of [2] to [4], wherein the adhesiveness of the contact portion is turned off by drying. [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. [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. [8] The partition member according to any one of [1] to [7], wherein the contact portion contains a water-soluble resin. [9] A partition member according to any one of [1] to [8], 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 battery is smaller than the bending strength of the partition member.

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

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

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

[12] The partition member according to

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

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

[12] arranged between the individual cells.

[14] A battery pack having a configuration in which unit cells, each having the partition member according to any one of [1] to

[12] attached to the surface of one side thereof, are stacked with the partition member sandwiched between them.

[15] A step of attaching the partition member according to any one of [1] to

[12] to the surface of a single cell in contact with the surface of the single cell; and housing the cell group, which is formed by stacking the partition member and the cells, in a housing that supports the cell group while restraining the cell group.

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

[15] , further comprising a step of adjusting the attachment position of the partition member to the unit cells.

[17] The method for manufacturing the battery pack according to

[15] or

[16] , further comprising a step of bringing moisture into contact with the contact portion of the partition member.

[18] A method of bringing the contact state of the partition member according to any one of [1] to

[12] into an on state and bringing it into close contact with the surface of the unit cell.

[19] A method for detaching the partition member according to any one of [1] to

[12] above from the surface of a cell by turning the contact state of the partition member to an OFF state.

[0013] As described above, one aspect of the present invention is a partition member whose surface is covered with an outer casing, which has a contact portion on the surface of the outer casing, and which is characterized in that the contact portion is capable of transitioning from an off state in which no adhesion is exhibited to an on state in which adhesion is exhibited. Another aspect of the present invention is a partition member comprising a porous body, a liquid, and an outer casing for containing these, characterized in that the outer casing surface has a contact portion that is in close contact with a non-contact body. The partition member can separate the individual cells of a plurality of cells housed in a stacked arrangement in the battery pack, the cells and battery components other than the cells, or the battery components other than the cells. The partition member is provided with a contact portion on its surface with which the cell or a battery component other than the cell comes into contact, and is detachable from the surface of the cell via this contact portion. Furthermore, the contact portion is located outside the exterior body relative to the porous body included in the partition member.

[0014] Here, the phrase "the partition member can be attached and detached to the surface of the cell via the contact portion" means that the partition member can be attached to the surface of the cell by sandwiching the contact portion provided on its surface, and can be maintained in this attached state, and when an external force is applied to separate the partition member attached to the cell from the cell, the attached partition member can be detached from the cell without deformation or deterioration of the contacting surfaces of the cell and the partition member, or the entire cell, and further, the detached partition member can be attached to the cell again, and the above-mentioned attachment and detachment operations to the cell can be performed repeatedly. According to this, when the partition member is placed on the single cell, the contact portion provided on the surface of the partition member is joined to the surface of the single cell, thereby fixing the partition member to the surface of the single cell, and the partition member can be removed from the single cell by applying force between the two members in a direction that separates the partition member from the single cell. Because the partition members are detachable from the cells, when attaching the partition members to the cells and arranging them in a row to assemble a module consisting of a group of cells, if a misalignment between the cell and the partition member is found, the misalignment can be corrected by a simple operation of first detaching the partition member from the misaligned cell and then reattaching it to the correct position. Before attaching the partition member to the correct position and fixing it to the cell, it is also possible to temporarily attach the partition member to the cell via the contact portion. The partition member can be attached to the single cell via the contact portion provided on its surface, so no plastic materials such as double-sided adhesive tape or wrap film are required to bond the two components together, and the operation of fixing the partition member to the single cell can be easily performed, thereby improving the workability and efficiency of assembling the module and battery pack.

[0015] In the partition member having the above-described configuration, the contact portion can be formed using a material having a property that allows transition between an ON state in which adhesion is present and an OFF state in which adhesion is not present. Here, the "ON state in which adhesion has appeared" refers to a state in which the device has a specific peel strength when attached to a battery and can be attached to the battery, and the "OFF state in which adhesion has not appeared" refers to a state in which adhesion is different from the ON state. Also, "capable of transitioning between an ON state in which adhesion has appeared and an OFF state in which adhesion has not appeared" refers to the ability to switch from the ON state to the OFF state and vice versa by performing a specific operation. The term "adhesion" refers to the state in which objects share an interface, that is, a surface, and refers to contact, adhesion, and adhesion between contacting portions and adherends.

[0016] The contact portion may be formed so that its adhesion is turned on by contact with water. Furthermore, the contact portion can be formed so that the adhesion is turned off when dried.

[0017] The contact portion may be formed so that the ratio of peel strength in the adhesive ON state to that in the adhesive OFF state is 1.5 to 1,000. The contact portion can be formed to have a peel strength of 0.001 to 0.10 N / 10 mm, or 0.001 N / 10 mm or more and less than 0.010 N / 10 mm. The contact portion can be made of a material containing a water-soluble resin. The contact portion may also be formed from a layer containing a water-soluble resin, and may also be formed from a layer containing polyvinyl alcohol. In this case, the water-soluble resin can exhibit adhesion by forming an interface with the adherend surface during the process of solidifying in water.

[0018] In the partition member having the above configuration, the contact portion can be provided so that the peel strength of the contact portion when the partition member is attached to the surface of the unit cell is smaller than the bending strength of the partition member.

[0019] The contact portion may be provided on at least one surface of the partition member. Contact portions may be provided on both side surfaces of the partition member that come into contact with the left and right cells.

[0020] The contact portion can be formed in a layer that occupies at least 50% or more of the area of ​​the surface of the partition member on which the contact portion is provided. 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. From the viewpoint of effectively switching the thermal conductivity, when the average surface temperature of the partition member is 25°C, it is preferable that the thermal conductivity of the contact portion in the thickness direction is 0.5 W / m·K or more, and that the thermal conductivity of the partition member is less than 0.25 W / m·K. When the average surface temperature of the partition member is 25°C, the thermal conductivity of the contact portion in the thickness direction is 0.5 W / m K or more, and the thermal resistance per unit area of ​​the partition member is 3.0 × 10 ―3 It is preferably less than K / W. The "average surface temperature" means the average temperature of any three points on the spacer surface that come into contact with the heating element.

[0021] The battery pack of the present invention is characterized by having a configuration including a plurality of unit cells and a plurality of partition members having the above-described configuration arranged between the individual cells. The battery pack having the above configuration is characterized in that it has a configuration in which unit cells, each having a partition member of the above configuration attached to a surface on one side, are stacked with the partition member sandwiched between them.

[0022] The present invention also provides a method for manufacturing a battery pack, comprising the steps of: attaching the partition member having the above-described configuration to a surface of a battery cell in contact with the surface of the battery cell; and a step of restraining the cell group formed by stacking the partition member and the cell group in a housing that supports the cell group. The manufacturing method is characterized by including a step of adjusting the mounting position of the partition member on the unit cell. The manufacturing method is characterized by including a step of detaching the partition member that has been in contact with the cell after installation, and then re-installing it. The method is also characterized by including a step of bringing moisture into contact with the contact portion of the partition member before mounting on the unit cell. The method is also characterized by including a step of bringing moisture into contact with the contact portion of the partition member after the battery is attached to the cell. The method for adhering the partition member also includes bringing the contact portion of the partition member into an on state and bringing the partition member into close contact with the surface of the cell. The method of attaching and detaching the partition member includes turning the contact portion of the partition member into the OFF state and detaching the partition member from the surface of the cell. [Effects of the Invention]

[0023] According to the partition member of the present invention, it is configured to be attachable and detachable to the surface of the single cell via a contact portion, so that the partition member can be joined and fixed in the appropriate position on the surface of the single cell and the two members can be stacked and arranged side by side.If a misalignment occurs in the stacked position, the partition member can be temporarily separated from the single cell, and then the separated partition member can be fixed in the appropriate position to correct the misalignment. [Brief explanation of the drawings]

[0024] [Figure 1] 1A is a schematic cross-sectional view showing an example of the configuration of a partition member of the present invention, and FIG. 1B is a cross-sectional end view taken along the line BB. [Figure 2] 1 is a diagram showing a configuration of an example of a battery pack of the present invention. [Figure 3] 3A and 3B are views showing the side surface and the top surface of a cell used in the battery pack of FIG. 2. [Figure 4] 10A and 10B are diagrams illustrating a process of fixing a partition member to a cell. [Figure 5] 10A and 10B are diagrams illustrating a process of stacking and arranging a plurality of unit cells to form a module of unit cell groups. DETAILED DESCRIPTION OF THE INVENTION

[0025] Preferred embodiments of the partition member and battery pack of the present invention will be described below. However, the embodiments described below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to the embodiments described below.

[0026] FIG. 1 shows a partition member according to one embodiment of the present invention. The illustrated partition member 1 is configured by enclosing a porous body 2 capable of retaining a liquid inside an exterior body 3 together with the liquid. More specifically, the partition member 1 has a configuration in which the exterior body 3 has a sealing portion 32 formed by sealing the edges of multilayer sheets 31, 31, each including a resin layer and a metal layer, in a strip shape, and a contact portion 4 is provided on one side of the exterior body 3 so that the partition member 1 can be attached to and detached from the surface of a cell 7, which will be described later, via this contact portion 4. The porous body 2 and a liquid may be sealed in the internal space surrounded by this sealing portion 32.

[0027] <Partition material> The partition member 1 is formed in the shape of a flat plate or sheet having an appropriate thickness, as shown in Fig. 1. The partition member 1 is used in the thickness direction to separate the cells constituting the battery pack, or to separate the cells constituting the battery pack from components other than the cells, for example, between the cells and the wall surface of a housing that houses the partition member. The partition member according to one aspect of the present invention may include a porous body, a liquid, and an exterior body that is a packaging material for containing these. Porous bodies typically have low thermal conductivity. The porous body included in the partition member is immersed in a liquid, and the voids therein are filled with the liquid, thereby increasing the thermal conductivity. Therefore, the thermal conductivity of the partition member can be made higher than that of the porous body itself. Furthermore, the partition member can reduce its thermal conductivity by causing the liquid inside to disappear at a certain temperature. From the viewpoint of increasing the rate of change in thermal conductivity, the porous body is preferably a heat insulating material.

[0028] [Porous body] The porous body is capable of retaining liquid and generally has elasticity. The elastic porous body shrinks or deforms in the thickness direction due to thermal expansion of the cell. In the example shown in Fig. 1, the porous body 2 is formed in the shape of a horizontally long rectangular flat plate or sheet. The porous body 2 is accommodated together with a liquid inside a larger rectangular flat plate or sheet-like exterior body 3, and is sealed inside the interior surrounded by a sealing portion 32 of the exterior body 3.

[0029] The porous body preferably includes a powdered inorganic material and a fibrous inorganic material. In the present invention, "fibrous inorganic material" refers to an inorganic material having a shape in which the major axis is 100 times or more the minor axis, and "powdered inorganic material" refers to an inorganic material having a shape in which the major axis is less than 100 times the minor axis. In particular, in the case of a fibrous material, the "major axis" refers to the fiber length, and the "minor axis" refers to the diameter of a cross section perpendicular to the major axis direction.

[0030] The fibrous inorganic material is preferably at least one selected from the group consisting of paper, cotton sheet, polyimide fiber, aramid 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. The ceramic fiber is a fiber mainly composed of silica and alumina (silica:alumina=40:60 to 0:100), and specifically, silica-alumina fiber, mullite fiber, and alumina fiber can be used.

[0031] Furthermore, the powdered inorganic material 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, xonotlite, tobermorite, wollastonite, and gyrolite are preferred, and gyrolite is particularly preferred. Gyrolite, which has a petal-like structure, maintains its porous structure even when compressed and deformed, and therefore has excellent liquid retention properties. Clay minerals are mainly magnesium silicate (including talc and sepiolite), montmorillonite, and kaolinite.

[0032] The porous body containing a fibrous inorganic material and a powdery inorganic material can be selected from known materials, for example, those described in JP-A-2003-202099.

[0033] The density of the porous body is 0.20 to 1.10 g / cm from the viewpoint of being lightweight and having excellent heat insulating properties even at high temperatures. 3 When the density of the porous body is equal to or greater than the lower limit, the porous body has many air layers in the internal voids, which is preferable from the viewpoint of heat insulation and liquid retention, while when the density is equal to or less than the upper limit, the porous body has a small deformation amount during compression, which is preferable. From these viewpoints, the density of the porous body is preferably 0.35 g / cm 3 More preferably, it is 0.55 g / cm or more. 3 or more, while preferably 1.05 g / cm 3 More preferably, it is 1.00 g / cm or less. 3 The following is the result.

[0034] 〔liquid〕 The liquid held in the porous body housed in the exterior body should be thermally conductive and capable of efficiently transferring heat generated from a cell to neighboring cells. Furthermore, the liquid preferably has a boiling point of 80°C or higher and 250°C or lower at normal pressure (1 atmosphere), and more preferably a boiling point of 100°C or higher and 150°C or lower at normal pressure. Water is particularly preferred because of its high heat of vaporization and its general availability.

[0035] The liquid preferably contains at least one selected from the group consisting of water, alcohols, esters, ethers, ketones, hydrocarbons, fluorine-based compounds, and silicone-based oils, and these may be used alone or as a mixture of two or more.

[0036] Examples of alcohols that can be used in the liquid include alcohols containing 3 to 8 carbon atoms, such as propanol, isopropanol, butanol, benzyl alcohol, and phenylethyl alcohol, and dihydric or higher alcohols, such as alkylene glycols, such as ethylene glycol and propylene glycol. These can be used alone or as a mixture of two or more.

[0037] Esters that can be used in the liquid include alkyl aliphatic carboxylate esters, alkyl carbonate diesters, alkyl oxalate diesters, and fatty acid esters of ethylene glycol. Examples of alkyl aliphatic carboxylate esters include lower alkyl formates such as methyl formate, n-butyl formate, and isobutyl formate; lower alkyl acetates such as n-propyl acetate, isopropyl acetate, n-butyl acetate, and isobutyl acetate; and lower alkyl propionates such as ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, and isobutyl propionate. Examples of alkyl carbonate diesters include lower alkyl carbonate diesters such as dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and methyl ethyl carbonate. Examples of alkyl oxalate diesters include lower alkyl oxalate diesters such as dimethyl oxalate and diethyl oxalate. Examples of fatty acid esters of ethylene glycol include ethylene glycol acetate ester. These can be used alone or in combination.

[0038] Examples of ethers that can be used in the liquid include n-butyl ether, n-propyl ether, isoamyl ether, etc. These can be used alone or as a mixture of two or more. Ketones that can be used in the liquid include ethyl methyl ketone, diethyl ketone, etc. These can be used alone or as a mixture of two or more.

[0039] Examples of hydrocarbons that can be used as the liquid include heptane, octane, nonane, decane, toluene, xylene, etc. These can be used alone or as a mixture of two or more.

[0040] Examples of fluorine-based compounds that can be used in liquid form include the refrigerants 1,1,2,2,3,3,4-heptafluorocyclopentane (HFC-c447ef) and 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorooctane (HFC-76-13sf). These can be used alone or as a mixture of two or more.

[0041] Examples of silicone oils that can be used in the liquid include modified silicone oils such as methylpolysiloxane, methylphenylpolysiloxane, cyclic methylsiloxane, and silicone polyether copolymers. These can be used alone or as a mixture of two or more.

[0042] The liquid may also contain antifreeze agents, preservatives, and pH adjusters. These may be used alone or as a mixture of two or more. The liquid may also contain additives such as substances that impart antifreeze properties (antifreeze agents), preservatives, and pH adjusters. The liquid is not limited to these, and other substances may be added as needed.

[0043] [Exterior body] As shown in Figure 1, the outer casing 3 contains a 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 each other in a strip-like shape.

[0044] The exterior body is flexible and can deform in response to the expansion of the unit cells. Furthermore, when the unit cells contract, the exterior body can return to its original state. Examples of the exterior body that can be used include a resin sheet and a resin film. For example, a porous body is sandwiched between two opposing or folded resin sheets or resin films, and the peripheral portion of the exterior body where the two resin sheets or resin films contact is sealed by a sealing means such as fusion or heat bonding, thereby sealing the liquid-impregnated porous body.

[0045] The outer casing can be made of, for example, resin or metal. A laminate of metal foil and resin is preferred from the viewpoint of high heat resistance and strength. As a metal-resin laminate, a laminate of three or more layers including a protective resin layer, a metal layer, and a sealant resin layer, or a multi-layer sheet, is preferred. On the other hand, a laminate of resin films is preferred because it provides flexibility and does not interfere with the moisture absorption effect of the inner packaging material. As a laminate of resin films, a laminate of two or more layers or a multi-layer sheet is preferred, such as a combination of a protective resin layer and a sealant resin layer, or a combination of a barrier protective resin layer with barrier properties, in which aluminum or silicon dioxide is vapor-deposited on the protective resin layer, and a sealant resin layer.

[0046] Examples of metals used for the metal foil and metal layer include aluminum, copper, tin, nickel, stainless steel, lead, tin-lead alloy, bronze, silver, iridium, phosphor bronze, etc. In particular, aluminum, copper, and nickel are preferred, and aluminum is more preferred.

[0047] The protective resin layer may be, but is not limited to, a polyolefin-based resin such as a homopolymer or copolymer of ethylene, propylene, or butene; an amorphous polyolefin-based resin such as a cyclic polyolefin; a polyester-based resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN); a polyamide-based resin such as nylon 6, nylon 66, nylon 12, or a copolymer nylon; a partially hydrolyzed ethylene-vinyl acetate copolymer (EVOH), a polyimide-based resin, a polyetherimide-based resin, a polysulfone-based resin, a polyethersulfone-based resin, a polyetheretherketone-based resin, a polycarbonate-based resin, a polyvinyl butyral-based resin, a polyarylate-based resin, a fluororesin, an acrylic resin, or a biodegradable resin. Among these, polyamide-based resins such as nylon 6 and polyester-based resins such as polyethylene terephthalate are preferred from the viewpoint of imparting heat resistance and mechanical strength as an exterior body. The protective resin layer may be a single layer or a laminate of two or more layers. In the case of two or more layers, the resin layers may be selected from different resin layers or from the same resin layer.

[0048] The sealant resin layer can be made of at least one of a thermosetting resin and a thermoplastic resin, with thermoplastic resins being particularly preferred. Examples of sealant resins include polyolefin-based resins such as homopolymers or copolymers of ethylene, propylene, and butene; amorphous polyolefin-based resins such as cyclic polyolefins; polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyvinyl butyral-based resins, acrylic resins, and biodegradable resins. Among these, at least one polyolefin-based resin selected from high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLPDE), polypropylene resin, and other polypropylene resins is preferred from the viewpoint of low-temperature melting properties required for the function of releasing liquid inside the exterior during abnormal heat generation. Furthermore, polypropylene resin is more preferred, with unstretched polypropylene resin being particularly preferred, from the viewpoint of long-term storage stability within the temperature range typically used as a partition member for a battery pack and versatility.

[0049] The thickness of the protective resin layer is not particularly limited, but from the viewpoint of providing mechanical strength, it is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. To ensure flexibility, it is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. There are no particular restrictions on the thickness of the metal layer, but from the viewpoint of ensuring moisture permeability and suppressing the occurrence of pinholes, it is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 12 μm or more. Furthermore, from the viewpoint of ensuring flexibility, it is preferably 50 μm or less, more preferably 35 μm or less, and even more preferably 20 μm or less. The thickness of the sealant resin layer is not particularly limited, but from the viewpoint of ensuring sealing properties, it is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. In order to ensure flexibility, the thickness is preferably 120 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. The thickness of the exterior body is not particularly limited, but taking into consideration the thickness of each layer described above and from the viewpoint of mechanical strength, it is preferably 30 μm or more, more preferably 45 μm or more, and even more preferably 65 μm or more. In addition, to ensure flexibility, it is preferably 280 μm or less, more preferably 210 μm or less, and even more preferably 150 μm or less.

[0050] Furthermore, the liquid and porous medium are sealed within the exterior body by joining the peripheral edges of two exterior bodies into a ring shape using sealing means such as fusion or thermal bonding. Alternatively, one exterior body may be folded and the peripheral edges joined using the sealing means to seal in the liquid and porous medium. The exterior body is preferably flexible, i.e., elastic, but may not be flexible.

[0051] It is preferable that the internal pressure of the exterior body is lower than the external pressure in order to sufficiently increase the temperature when pores are generated. Therefore, it is particularly preferable to vacuum seal the exterior body. Furthermore, it is possible to control the temperature when pores are generated by adjusting the internal pressure.

[0052] [Contact part] As shown in Figure 1, the contact portion 4 is provided on the surface of the outer casing 3 on one side of the partition member 1, which is formed in a flat or sheet shape, and the partition member 1 can be attached and detached to the surface of the battery pack or the surface of the single cell via this contact portion 4.

[0053] The contact portion 4 can be formed using a material that exhibits adhesion upon contact with water, such as a water-soluble resin. Such a material is preferable because it has a function of not being adhesive when dry, but exhibiting adhesiveness when moisture is added as the water-soluble resin dissolves or swells again.

[0054] Furthermore, the contact portion 4 can be formed from a material that has a peel strength of 0.001 to 0.1 N / 10 mm as measured in accordance with JIS Z 0237 when the contact portion 4 is brought into contact with water and then left to stand for 5 minutes or more under a load so that the adherend and the contact portion are in contact. The peel strength is preferably a peel strength to any adherend, and more preferably a peel strength to the surface of the exterior body of a unit cell. From the viewpoint of facilitating positioning since the adhesive does not come into close contact with the adherend, the peel strength in the on state is preferably 0.01 to 0.8 N / 10 mm, and more preferably 0.01 to 0.5 N / 10 mm. The peel strength in the off state can be obtained by carrying out the measurement after drying for 3 days or more in an environment of 23°C with a dew point of -80°C, where the adherend and the contact portion are not in contact with each other. From the viewpoint of preventing blocking of films during transport, the peel strength is preferably 0.001 N / 10 mm or more and less than 0.01 N / 10 mm.

[0055] The contact portion 4 can be made of a material containing a water-soluble resin. The water-soluble resin is not particularly limited as long as it functions as a remoistenable adhesive, and examples of suitable water-soluble resins include various starches such as oxidized starch and etherified starch, glue, gum arabic, gum tragacanth, dextrin, polyvinyl alcohol, vinyl acetate resin, polyvinyl ethers such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, cellulose derivatives such as polyvinylpyrrolidone, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, ethylhydroxyethyl cellulose, and viscose, polyethylene glycol, polyethylene oxide, casein, gelatin, and sodium alginate. Of these, polyvinyl alcohol is particularly preferred from the viewpoint of adhesiveness.

[0056] 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 mol % to 99 mol %, more preferably 80 to 90 mol %. Whether the saponification degree is low or high, water solubility and adhesive strength tend to decrease.

[0057] The average degree of polymerization of the polyvinyl alcohol resin used in the present invention (measured in accordance with JIS K 6726:1994) is usually 100 to 4000. From the viewpoint of improving adhesion, it is preferably 200 to 3000, more preferably 300 to 2800, and even more preferably 500 to 2500. If the average degree of polymerization is too low, the adhesive strength tends to decrease, whereas if it is too high, the viscosity of the aqueous solution during film formation tends to be high, resulting in reduced productivity.

[0058] The degree of polymerization of the polyvinyl alcohol-based resin can generally be expressed by its aqueous viscosity, and the viscosity of a 4 wt % aqueous solution of the polyvinyl alcohol-based 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, from the viewpoint of improving adhesion. If the viscosity is too low, the adhesive strength tends to decrease, whereas if the viscosity is too high, the viscosity of the aqueous solution during film formation tends to be high, resulting in reduced productivity.

[0059] Furthermore, when the polyvinyl alcohol resin is a modified polyvinyl alcohol resin, the modification rate in such modified polyvinyl alcohol resin, i.e., the content of structural units derived from various monomers in the copolymer or functional groups introduced by a post-reaction, cannot be generally determined because the properties vary greatly depending on the type of functional group, but is usually 0.1 to 20 mol %. By using the above materials, the contact portion 4 can be provided with an adhesiveness that allows the partition member to be fixed to the surface of the unit cell.

[0060] In the present invention, a filler or the like may further be contained, if necessary.

[0061] Fillers are preferably contained in view of blocking resistance, and specific examples include inorganic fillers and organic fillers, with organic fillers being preferred. The average particle size is preferably 0.1 to 20 μm, and more preferably 0.5 to 15 μm. The average particle size can be measured, for example, with a laser diffraction particle size distribution analyzer.

[0062] From the viewpoint of improving the blocking effect, the inorganic filler preferably has an average particle size of 1 to 10 μm. If the average particle size is too small, it tends to be difficult to obtain the blocking resistance effect, while if the average particle size is too large, pinholes tend to form when the water-soluble film is stretched during molding processing, or the appearance tends to deteriorate.

[0063] Specific examples of inorganic fillers include talc, clay, silicon dioxide, diatomaceous earth, kaolin, mica, asbestos, gypsum, graphite, glass balloons, glass beads, calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite, calcium carbonate, whisker-like calcium carbonate, magnesium carbonate, dawsonite, dolomite, potassium titanate, carbon black, glass fiber, alumina fiber, boron fiber, processed mineral fiber, carbon fiber, hollow carbon spheres, 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 may be used alone or in combination of two or more.

[0064] From the viewpoint of improving the blocking effect, the organic filler preferably has an average particle size of 0.5 to 20 μm, more preferably 0.5 to 10 μm, particularly preferably 0.5 to 7 μm, and especially preferably 0.5 to 5 μm. If the average particle size is too small, it tends to be difficult to obtain an anti-blocking effect, and if it is too large, pinholes tend to form when the water-soluble film is stretched during molding processing.

[0065] Examples of the organic filler include starch, melamine-based resins, polymethyl (meth)acrylate-based resins, polystyrene-based resins, and biodegradable resins such as polylactic acid. Among these, it is particularly preferable to use biodegradable resins such as polymethyl (meth)acrylate-based resins, polystyrene-based resins, and starch as the organic filler. These can be used alone or in combination of two or more.

[0066] Examples of the starch include raw starches (corn starch, potato starch, sweet potato starch, wheat starch, ossava starch, sago starch, tapioca starch, sorghum starch, rice starch, bean starch, arrowroot starch, bracken starch, lotus starch, and water chestnut starch), physically modified starches (α-starch, fractionated amylose, and heat-moisture treated starch), enzyme-modified starches (hydrolyzed dextrin, enzymatically decomposed dextrin, and amylose), chemically decomposed and modified starches (acid-treated starch, hypochlorite-oxidized starch, and dialdehyde starch), and chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, and cross-linked starch). Among these, raw starches, particularly corn starch and rice starch, are preferred due to their availability and economical efficiency. These starches may be used alone or in combination of two or more.

[0067] From the viewpoint of improving the blocking effect, the content of the filler, when contained, 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 low, blocking resistance tends to decrease, and if the content is too high, pinholes tend to form when the water-soluble film is stretched during molding and processing.

[0068] The peel strength of the contact portion 4 is In the on state where adhesion appears, The peel strength can be measured by the method described in JIS K 6854. If the peel strength of the contact portion 4 is smaller than the bending strength of the partition member, the partition member can be separated from the cell without deforming it.

[0069] The contact portion 4 may be provided on the surface of the laminated sheet 31 on one side of the partition member 1 as shown in FIG. 1, or may be provided on the surface of the exterior body 31 on both the left and right sides of the partition member 1.

[0070] The contact portion 4 can be a layer formed over an area of ​​at least 50% or more of the surface of the laminated sheet 31 on which the contact portion of the partition member 1 is provided. If the layer is formed over 50% or more of the area, uneven adhesion to the adherend caused by bending of the film having the contact portion can be alleviated, and therefore sufficient adhesion can be ensured, which is preferable.

[0071] 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. A thickness of the layer equal to or greater than the lower limit is preferred from the viewpoint of preventing blocking of films during transport, while a thickness of equal to or less than the upper limit is preferred from the viewpoint of ensuring sufficient adhesion to the adherend. A thickness outside the range may cause coating voids at contact areas or uneven thickness.

[0072] The partition member 1 having the above-described configuration is formed by sealing the peripheral edges of two planar rectangular exterior bodies (laminated sheets) 31, 31 arranged opposite each other and having the contact portion 4. The porous body 2 holding the liquid can be sealed in the sealed internal space surrounded by the sealing portion 32. Alternatively, the contact portion 4 may be provided after the peripheral portions of the exterior body not having the contact portion 4 are sealed together in a strip shape.

[0073] When the partition member 1 configured in this manner is placed over the single cell, the contact portion 4 provided on the surface of the partition member 1 is joined to the surface of the single cell, thereby fixing the partition member 1 to the surface of the single cell.Furthermore, the partition member 1 can be removed from the single cell by applying force between the two members in a direction that separates the partition member 1 from the single cell. Because the partition member 1 can be attached and detached freely from the battery cells, if a misalignment between the battery cells and the partition member 1 is found when assembling a module consisting of a group of battery cells, the misalignment can be corrected by a simple operation of first separating the partition member 1 from the misaligned battery cells and then reattaching it to the correct position, thereby improving the workability and efficiency of assembling the module and battery pack. In addition, when the partition member 1 attached to the single battery is heated by the single battery, the internal pressure of the partition member 1 increases, causing the partition member 1 to open and the internal liquid to be ejected to the outside, switching the thermal resistance of the porous body 2 sealed inside the partition member 1 to exhibit high thermal resistance.This makes it possible to cool the single battery in contact with the partition member 1 that has experienced an abnormal temperature rise, while also suppressing heat conduction to adjacent single batteries.

[0074] <Battery pack> FIG. 2 shows an example of the configuration of a battery pack in which unit cells are separated by the partition member 1 having the above-described configuration, and FIG. 3 shows an example of the configuration of unit cells that make up the battery pack.

[0075] The cells 7 used in the battery pack 6 are usually called rectangular cells or pouch-shaped cells, and are rectangular parallelepiped cells with appropriate thickness, width, and height, and are formed with electrode terminals 71, 71 on their top or side surfaces. The cell 7 is, for example, a lithium ion secondary battery including a positive electrode and a negative electrode capable of absorbing and releasing lithium ions, and an electrolyte. In addition to lithium ion secondary batteries, other secondary batteries that can be used include all-solid-state lithium ion batteries, lithium polymer batteries, lithium metal batteries, lithium-sulfur batteries, lithium-air batteries, all-resin batteries, sodium-sulfur batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and lead-acid batteries.

[0076] The battery pack 6 contains a plurality of cells 7 stacked and arranged inside a housing 6 having a bottom wall 61, four side walls 62, and a cover member (not shown). The cells 7 are separated by partition members 1 having the above-described configuration, and adjacent cells 7 are separated in the thickness direction of the partition members 1. The positive and negative electrode terminals 71, 71 of adjacent cells 7 are electrically connected in series or in parallel, or in a combination of series and parallel, by bus bars (not shown), allowing the battery pack 5 to output a predetermined power. A large battery pack can be configured by electrically connecting multiple battery packs in series, in parallel, or in a combination of series and parallel. In this case, the large battery pack may have partition members having the same configuration as the partition member 1 disposed between the battery packs inside.

[0077] The battery pack 6 can be manufactured through the steps of attaching the partition member 1 to the surface of the single cells 7 by contacting it via the contact portion 4 of the partition member 1, as shown in Figure 4; stacking the single cells 7 with the partition member 1 attached, sandwiching the partition member 1 between them, as shown in Figure 5; and restraining the stacked group of single cells and storing them in the casing 6 that supports the group of single cells. The manufacturing process may include a step of adjusting the attachment position of the partition member 1 to the single battery 7, a step of bringing moisture into contact with this layer to create adhesion if the contact portion 4 of the partition member 6 has a layer containing a water-soluble resin, or a step of attaching the partition member 1 to the single battery 7.

[0078] The partition member 1 is preferably located outside the cells 7 and housed inside the battery pack 6, and in this case, the area ratio of the partition member 1 to the area of ​​the contact surface of the adjacent cells 7 with the partition member 1 (area of ​​the partition member / area of ​​the contact surface of the cells with 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. When the ratio is within this range, there are tendencies such as promoting heat transfer between the cells at room temperature, making the seal part more likely to rise in temperature and burst when the cells abnormally heat up, applying greater internal pressure to the seal part and making it more likely to burst when the cells abnormally heat up, and providing better insulation between the cells when the cells abnormally heat up. To prevent the seal portion from overheating and rupturing when an electric cell generates abnormal heat, it is desirable that the width of the seal portion be set so that the seal portion of the partition member overlaps the contact surface of the adjacent electric cell with the partition member, and that the dimensions are such that the entire area inside the inner edge of the seal portion is located inside the contact surface of the adjacent electric cell with the partition member.

[0079] The assembled battery is applied to battery packs mounted in, for example, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric heavy machinery, electric motorcycles, electrically assisted bicycles, ships, aircraft, trains, uninterruptible power supplies (UPSs), home energy storage systems, storage battery systems for stabilizing power systems that use renewable energy such as wind, solar, tidal, and geothermal power, etc. However, the assembled battery can also be used as a power source that supplies power to devices other than the above-mentioned EVs. [Example]

[0080] Preferred embodiments of the contact portion of the partition member of the present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0081] (Sample preparation) Sample partition members were fabricated using an exterior body consisting of an aluminum laminate film (a 15 μm-thick biaxially oriented 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 5 μm-thick polyurethane adhesive layer between each layer, for a total thickness of 67 μm). The peripheral dimensions of the partition member of the sample were 145 mm x 90 mm, and the size of the inner enclosure (vermiculite sheet; thickness 1 mm) made of a porous sheet enclosed inside was 112 mm x 58 mm.Five of these inner enclosures were stacked and a small amount of water was enclosed inside so that the thickness of the internal space arrangement part was 5 mm and the weight of the entire sample was 20 g. The sample partition members prepared under the above conditions were tested to determine the degree of adhesion when attached to the surface of a unit cell. The test involved applying water as evenly as possible to one side of the partition member using a sponge, pressing the wet side against an aluminum plate representing a single cell, then inverting it 180 degrees (so that the pressed side was facing up and the partition member was facing down), and measuring the time it took for the plate to fall to evaluate adhesion. The amount of water applied with the sponge was 10 mg.

[0082] Example 1 An aqueous solution of polyvinyl alcohol (product name: Gohsenol GH-17R, manufactured by Mitsubishi Chemical Corporation) was applied to the surface of one side of the partition member of the prepared sample, and dried in a dryer at 80°C for 5 minutes to form a contact part consisting of an adhesive layer with a thickness of 1 μm. The test was carried out on the contact portion of the partition member by applying 10 mg of water. The results are shown in Table 1.

[0083] Example 2 A partition member was produced under the same conditions as in Example 1, except that the thickness of the adhesive layer was set to 3 μm, and the same test was carried out. The results are shown in Table 1.

[0084] Example 3 A partition member was produced under the same conditions as in Example 1, except that the thickness of the adhesive layer was set to 0.5 μm, and the same test was carried out. The results are shown in Table 1.

[0085] Example 4 A partition member was produced under the same conditions as in Example 1, except that the thickness of the adhesive layer was 1 μm, and 5 mg of water was applied to the contact portion, followed by a similar test. The results are shown in Table 1.

[0086] [Table 1]

[0087] The test results confirmed that the adhesion could be controlled by adjusting the thickness of the contact layer and the amount of water in contact. The adhesion of the contact layer of each of the partition members in the above examples transitioned from an ON state to an OFF state.

[0088] The above-described configuration of the partition member and the battery pack of the present invention is one example, and can be appropriately changed based on design requirements and the like within the scope of the present invention.

[0089] In this specification, when "X to Y" or "X to Y" (X and Y are arbitrary numbers) is expressed, unless otherwise specified, it includes the meaning of "X or more and Y or less", as well as "preferably larger than X" and "preferably smaller than Y". Furthermore, when the expression "X or more" (X is any number) is used, it includes the meaning "preferably greater than X" unless otherwise specified, and when the expression "Y or less" (Y is any number) is used, it includes the meaning "preferably smaller than Y" unless otherwise specified. [Explanation of symbols]

[0090] 1 Partition member, 2 Porous body, 3 Exterior body, 31 Multilayer sheet, 32 Sealing portion, 4 Contact portion, 5 Battery pack, 6 Housing, 61 Bottom wall portion, 62 Side wall portion, 7 Cell, 71 Electrode terminal

Claims

1. A partition member that is stored together with a plurality of single cells within a battery pack and separates each of the single cells, the surface of which is covered with an exterior body, the exterior body having a contact portion on its surface that comes into contact with the single cells, the contact portion being capable of transitioning between an ON state in which adhesion is present and an OFF state in which adhesion is not present, the contact portion in the ON state in which adhesion is present having a peel strength of 0.001 to 0.8 N / 10 mm, and the contact portion is arranged so that the peel strength is smaller than the bending strength of the partition member, and the partition member is configured to be attachable to and detachable from the surface of the single cells via the contact portion.

2. A partition member that is stored together with a plurality of single cells within a battery pack and separates the individual cells, the surface of which is covered with an exterior body, the exterior body having a contact portion on its surface that comes into contact with the single cells, the contact portion being capable of transitioning between an ON state in which adhesion is present and an OFF state in which adhesion is not present, the contact portion in the ON state in which adhesion is present having a peel strength of 0.001 to 0.8 N / 10 mm, and the contact portion being a layer formed over an area of ​​at least 50% or more of the surface of the partition member, the layer having a thickness of 0.1 to 20 μm.

3. 2. The partition member according to claim 1, comprising a porous body, water, and an exterior body containing these, and a contact portion that comes into close contact with the contacted body is provided on the surface of the exterior body.

4. 3. The partition member according to claim 2, comprising a porous body, water, and an exterior body containing these, and a contact portion that comes into close contact with the contacted body is provided on the surface of the exterior body.

5. 3. The partition member according to claim 1, wherein the ratio of peel strength in the contact area in the on-state to the off-state is 1.5 to 1,000.

6. 3. The partition member according to claim 1, wherein the adhesiveness of the contact portion is turned on by contact with water.

7. 3. The partition member according to claim 1, wherein the adhesiveness of the contact portion is turned off when the contact portion is dried.

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

9. 3. The partition member according to claim 1, wherein the partition member has a contact portion on one side thereof.

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

11. 3. A battery pack comprising a plurality of unit cells and a plurality of partition members according to claim 1 or 2 arranged between the cells.

12. 3. A battery pack having a configuration in which unit cells, each having the partition member according to claim 1 or 2 attached to a surface on one side thereof, are stacked with the partition member sandwiched between them.

13. a step of attaching the partition member according to claim 1 or 2 to a surface of a unit cell in contact therewith; and housing the cell group formed by stacking the partition member and the cells in a housing that supports the cell group while restraining the cell group.

14. The method for manufacturing a battery pack according to claim 13 , further comprising the step of bringing moisture into contact with the contact portion of the partition member.

Images