Separating member and battery pack

Abstract

A partition member has a thickness direction and a plane direction orthogonal to the thickness direction, and partitions in the thickness direction between unit cells constituting a battery pack or between the unit cells constituting the battery pack and members other than the unit cells. The partition member is characterized by having, in the interior thereof: a fluid having a boiling point at atmospheric pressure of 80-250 DEG C (inclusive); and a fluid flow path extending in the plane direction, the fluid being held by the fluid holding part, and the fluid holding part being sealed by the packaging material.

Description

[0001] This application is a divisional application of an application with an international application date of March 16, 2018 (date of entry into the Chinese national phase: September 17, 2019), an international application number of PCT / JP2018 / 010444 (national application number: 201880018792.1), and an invention name of “Partitioning member and battery pack”. Technical Field

[0002] The present invention relates to a partition member and a battery pack. Background Art

[0003] In recent years, the use of secondary batteries as power sources for vehicles has increased dramatically. Research on the high energy density of secondary batteries is being promoted for the purpose of increasing the degree of freedom when mounted in a limited space of a vehicle or the like and extending the driving distance that can be traveled on a single charge.

[0004] On the other hand, the safety of secondary batteries tends to be opposite to the energy density, and the higher the energy density, the lower the safety. For example, in a secondary battery installed in an electric car that can extend the cruising range to hundreds of kilometers, the surface temperature of the battery will exceed hundreds of degrees Celsius, and sometimes reach nearly 1000 degrees Celsius when the secondary battery is damaged by overcharging, internal short circuit, etc.

[0005] Secondary batteries used in power sources for vehicles and the like generally use a battery pack composed of a plurality of cells (hereinafter also referred to as "battery cells"). Therefore, if one of the cells constituting the battery pack is damaged and reaches the temperature range described above, the adjacent cells will be damaged due to the heat generated, and there is a possibility that the damage will be extended to the entire battery pack in a chain reaction. In order to prevent such chain damage between cells, various technologies for cooling damaged cells and technologies for suppressing heat transfer from damaged cells to undamaged cells have been proposed.

[0006] For example, Patent Document 1 discloses a battery assembly having a cooling unit containing a coolant such as water in a sheet-like bag, the cooling unit having a sealing portion formed by sealing the sheet-like member, and having an opening portion that is opened when the single battery is abnormally heated. In addition, Patent Document 2 discloses a partition member having a structure in which a porous body impregnated with a coolant such as water is placed in a sheet-like bag. Since the partition member uses a porous body, the capillary force thereof can be utilized to move the coolant such as water to the heating part without waste, and the heat of vaporization of the sealed coolant such as water is used more efficiently. In addition, Patent Document 3 describes a battery pack designed as follows: a filler having a fire extinguishing property is filled in the inner cavity of the partition member, and the partition member opens due to heat, thereby allowing the filler to flow out to the outside. In addition, Patent Document 4 discloses a battery pack system in which two adjacent square battery cans are arranged in parallel with their sides with larger areas facing each other, a cooler is provided between the two adjacent square battery cans, and the cooler has an opening and a partition wall for forming a flow path for a cooling medium between its opposite sides to the two adjacent square battery cans.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 2012 / 032697

[0010] Patent Document 2: Japanese Patent Application Publication No. 2013-131428

[0011] Patent Document 3: Japanese Patent Application Publication No. 2009-004362

[0012] Patent Document 4: Japanese Patent Application Publication No. 2011-192642 Summary of the invention

[0013] Problem that the invention aims to solve

[0014] The present inventors have studied the partition members disclosed in Patent Documents 1 to 4 in detail and have found the following disadvantages.

[0015] That is, the partition member disclosed in Patent Document 1 utilizes the heat of vaporization and fire extinguishing capability of a coolant such as water when abnormal heat is generated, and only utilizes the latent heat generated when the sealed coolant such as water vaporizes once, and has a small heat dissipation capability. Furthermore, when an abnormality occurs, the heat of vaporization of the contained coolant such as water is released instantaneously, and therefore the heat of vaporization of the contained coolant such as water cannot be fully utilized.

[0016] Furthermore, in the partition member disclosed in Patent Document 2, only latent heat generated when a coolant such as water is vaporized once can be used.

[0017] In addition, the partition member disclosed in Patent Document 3 utilizes the fire extinguishing function when the fire extinguishing filler such as water in the partition member flows out to the outside in an abnormal situation, and can only utilize the latent heat generated when the sealed filler is vaporized once.

[0018] Furthermore, in the partition member disclosed in Patent Document 4, the function of removing heat generated by the battery cell is utilized by heat transfer relative to the refrigerant and heat absorption accompanying the vaporization of the refrigerant. The heat transfer of the refrigerant refers to the refrigerant flowing into the interior of the partition member through the flow path from the outside of the partition member, and flowing out to the flow path outside the partition member after circulating inside the partition member. By providing a heat exchanger in the flow path outside the partition member, the multiple vaporization heat of the refrigerant can be used for cooling the battery cell. However, in addition to the partition member, external piping, external liquid feeding device, heat exchanger, etc. are required, which has the disadvantage of increasing the weight and volume of the battery pack including the cooling function. In addition, in the case of abnormality in the external liquid feeding device or the flow path outside the partition member of the refrigerant, when the circulation of the refrigerant is stopped, only the latent heat generated when the refrigerant is vaporized once can be used.

[0019] It is thus clear that in the battery cells and assemblies disclosed in Patent Documents 1 to 4, in the case of local abnormal heating, the function of safely cooling the abnormal heating portion is insufficient without causing thermal runaway of the cells around the abnormally heated cell due to heat transfer from the abnormally heated cell. In addition, it is clear that in the battery cell and assembly of the battery pack system disclosed in Patent Document 4, there is a disadvantage that the weight and volume of the battery pack including the cooling function become larger.

[0020] In view of the above problems, the present invention provides a partition member and a battery pack, which can safely promote the cooling of the abnormally heated portion without causing thermal runaway of the single cells around the abnormally heated portion when the single cells constituting the battery pack become abnormally heated. In addition, the present invention provides a partition member and a battery pack having such a function in a lightweight and compact form.

[0021] Solutions for solving problems

[0022] In the technologies described in Patent Documents 1 to 3, it is envisaged that heat is captured by evaporation of a coolant such as water, and it is envisaged that the heat of the partition member is mainly transferred only between the surface of the single cell. That is, in these technologies, the latent heat of evaporation is used for cooling only in one single cell that is generating heat. In addition, in the technology described in Patent Document 4, it is envisaged that the refrigerant flows into the partition member from the outside and flows out from the partition member to the outside. That is, in this technology, in addition to the partition member, piping for external flow paths and an external liquid supply device are also used. In contrast, the inventors of the present invention have thought that when abnormal heat is generated in a single cell, by controlling the direction of heat transfer of the partition member in contact with the single cell, heat transfer is controlled not only for the single cell generating heat in particular, but also for other single cells parallel to the single cell in the surface direction of the partition member. In addition, it is considered that by using only such a partition member to effectively utilize the heat capacity of the single battery itself and the component structure and use the single battery itself and the component structure as a heat sink, the cooling of the abnormal heating part can be safely promoted while making the component light and small and without causing thermal runaway of normal battery cells around the abnormal heating part.

[0023] Furthermore, as a structure that embodies the partition member having the above functions, it has been found that by filling the partition member with a fluid having a boiling point that vaporizes when abnormal heat is generated and providing a flow path for the fluid to move, the heat movement direction can be switched by temperature to efficiently perform heat removal and cooling. That is, the present invention is as follows.

[0024] (1) A partition member having a thickness direction and a surface direction orthogonal to the thickness direction, and separating single cells constituting a battery pack or single cells constituting the battery pack from components other than the single cells in the thickness direction, the partition member being characterized in that it contains: a fluid having a boiling point of 80°C or more and 250°C or less at normal pressure; and a flow path for the fluid extending along the surface direction, the fluid being retained by a fluid retaining portion, and the fluid retaining portion being sealed by a packaging material.

[0025] (2) A partition member having a thickness direction and a surface direction orthogonal to the thickness direction, and separating single cells constituting a battery pack or single cells constituting the battery pack from components other than the single cells in the thickness direction, the partition member being characterized in that it has: a fluid retaining portion inside thereof, which is capable of retaining a fluid having a boiling point of not less than 80°C and not more than 250°C at normal pressure; and a flow path for the fluid, which extends along the surface direction, and the fluid retaining portion is sealed by a packaging material.

[0026] (3) A partition member according to (1) or (2), wherein the flow path includes a continuous space having a length of more than 1 mm through which the fluid can move, and a diameter of a ball that can be inscribed in the space is more than 0.1 mm in an area that accounts for more than 90% of the volume of the space.

[0027] (4) The partition member according to any one of (1) to (3), wherein the fluid contains at least one substance selected from the group consisting of water, alcohols, esters, ethers, ketones, hydrocarbons, fluorine compounds, and silicone oils.

[0028] (5) The partition member according to any one of (1) to (4), wherein a porous body capable of containing the fluid is provided inside the partition member, and the flow path is formed in the porous body.

[0029] (6) The partition member according to (5), wherein the porous body includes at least one of a fibrous layer and a particle layer.

[0030] (7) A partition member according to (6), wherein the porous body includes a fibrous layer, and the porous body is at least one material selected from the group consisting of glass fiber sheets, ceramic fiber sheets, paper, cotton sheets, porous ceramic plates, porous glass plates, polyimide fiber sheets, aramid fiber sheets, and polytetrafluoroethylene fiber sheets.

[0031] (8) The partition member according to (6) or (7), wherein the porous body includes a particle layer, and the porous body is at least one material selected from the group consisting of silica particles, alumina particles, zeolite particles, glass particles, and carbon particles.

[0032] (9) The partition member according to any one of (1) to (8), wherein a length of the flow path in a height direction or a width direction of the partition member is equal to or greater than 1 / 2 of a length of the partition member in the height direction or the width direction.

[0033] (10) The partition member according to any one of (1) to (9), wherein the partition member includes a packaging material, and the packaging material includes the porous body therein.

[0034] (11) A battery pack comprising the partition member according to any one of (1) to (10).

[0035] (12) The battery pack according to (11), wherein the plane direction of the partition member includes a width direction of the partition member, and a length of the partition member in the width direction is longer than a length of a single cell partitioned by the partition member in the width direction.

[0036] (13) A battery pack according to (11) or (12), wherein one of the two surfaces in the thickness direction of the partition member has a first region opposite to a first single cell in the battery pack and a second region not opposite to the first single cell, and the second region is opposite to a second single cell different from the first single cell in the battery pack and at least one of a member other than a single cell.

[0037] (14) A battery pack according to (13), wherein the other of the two surfaces in the thickness direction of the partition member is opposite to a third cell that is different from the first cell and the second cell and is not opposite to the first cell across the partition member, and at least one of members other than the cells in the battery pack.

[0038] (15) A battery pack according to (11), wherein one of the two surfaces of the partition member in the thickness direction is opposite to a first single cell among the plurality of single cells, and the other of the two surfaces of the partition member in the thickness direction is opposite to a single cell in the battery pack that is different from the first single cell and is not opposite to the first single cell across the partition member, and at least one of a member other than a single cell in the battery pack.

[0039] Effects of the Invention

[0040] According to the partition member and the battery pack of the present invention, when the cells constituting the battery pack are in an abnormally heated state, the abnormally heated portion can be safely cooled without causing thermal runaway of the cells located around the abnormally heated portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 (A) is a front view showing a structural example of a partition member according to an embodiment, Figure 1 (B) means Figure 1 (A) is a left view of the partition member shown.

[0042] Figure 2 It is a diagram showing an example of a flow path included in a fluid retaining portion provided inside a partition member.

[0043] Figure 3 (A) is a plan view showing an example of a single battery (battery unit) constituting a battery pack. Figure 3 (B) is a front view showing an example of a single battery (battery unit). Figure 3 (C) is a side view showing an example of a single battery (battery unit).

[0044] Figure 4It is a plan view showing an example of a battery pack formed using a plurality of unit cells.

[0045] Figure 5 It means cutting using the AA line Figure 4 A diagram of the end face of a battery case is shown.

[0046] Figure 6 It is a diagram for explaining the function of the partition member 1.

[0047] Figure 7 This is a diagram schematically showing a first situation in which one of a plurality of cells arranged in a row reaches a high temperature.

[0048] Figure 8 This is a diagram schematically showing a second situation in which a local high-temperature portion is generated in one single cell.

[0049] Fig. 9 It means in Figure 4 FIG. 1 is a diagram showing a heat transfer path when a single cell in a battery pack generates abnormal heat.

[0050] Fig.10 It means in Figure 4 FIG. 1 is a diagram showing a heat transfer path when a single cell in a battery pack generates abnormal heat.

[0051] Fig.11 It indicates the implementation mode ( Figure 4 ) is a diagram of variant example 1 of .

[0052] Fig.12 It indicates the implementation mode ( Figure 4 ) is a diagram of a second variant example.

[0053] Fig.13 (A) is a front view schematically showing the structure of a member used in a measurement test of a heat flow rate flowing in a partition member of Example 1, Fig.13 (B) is its side view.

[0054] Fig.14 Graph showing temperature changes on the high temperature side and the low temperature side of the partition member of Example 1.

[0055] Fig.15 This is a graph showing temperature changes on the high temperature side and the low temperature side of the partition member of Comparative Example 1.

[0056] Fig.16 This is a graph showing temperature changes on the high temperature side and the low temperature side of the partition member of Comparative Example 2.

[0057] Fig.17 This is a graph showing temperature changes on the high temperature side and the low temperature side of the partition member of Example 2.

[0058] Fig.18 This is a graph showing temperature changes on the high temperature side and the low temperature side of the partition member of Example 3.

[0059] Description of Reference Numerals

[0060] 1. Partition member; 2. Battery cell, single battery; 3. Casing; 4. Bus bar; 10. Battery pack; 11. Fluid retaining portion; 12. Flow path; 13. Packaging material. DETAILED DESCRIPTION

[0061] The following description of the components is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist of the present invention.

[0062] In the present embodiment, the "abnormal heating state" of the single cell constituting the battery pack means that a short circuit occurs inside the single cell and heat is generated, thereby causing a decomposition reaction to cause a part or all of the single cell to be in a state above 200°C. In addition, "thermal runaway" refers to a phenomenon in which the single cell becomes abnormally heated and the heating rate of the single cell exceeds the cooling rate and the temperature cannot be controlled. "Normal" (normal temperature) means that the temperature of the single cell is below 80°C, but if the upper limit temperature of use specified by the manufacturer, that is, the upper limit temperature at which the single cell is normally charged and discharged without drastic capacity deterioration, is above 80°C, then "normal" (normal temperature) means that the single cell is below this temperature.

[0063] 〔Separation member〕

[0064] The partition member of the present embodiment is a partition member having a thickness direction and a surface direction orthogonal to the thickness direction, and partitioning between the cells constituting the battery pack or between the cells constituting the battery pack and members other than the cells in the thickness direction. The partition member is characterized in that it has a fluid having a boiling point of 80°C or more and 250°C or less at normal pressure, and a flow path of the fluid extending along the surface direction, the fluid being held by a fluid holding portion, and the fluid holding portion being sealed by a packaging material. In addition, another partition member of the present embodiment is a partition member having a thickness direction and a surface direction orthogonal to the thickness direction, and partitioning between the cells constituting the battery pack or between the cells constituting the battery pack and members other than the cells in the thickness direction. The partition member is characterized in that it has a fluid holding portion capable of holding a fluid having a boiling point of 80°C or more and 250°C or less at normal pressure, and a flow path of the fluid extending along the surface direction, and the fluid holding portion being sealed by a packaging material. In other words, the partition member of this embodiment comprises: a fluid retaining portion capable of retaining a fluid having a boiling point of greater than 80°C and less than 250°C at normal pressure; a flow path for the fluid, the flow path extending along the surface direction; and a packaging material that seals and accommodates the fluid retaining portion and the flow path.

[0065] Figure 1 (A) is a front view showing a structural example of a partition member according to an embodiment, Figure 1 (B) shows Figure 1 (A) is a left view of the partition member shown. Figure 2 An example of a flow path included in the fluid retaining portion provided inside the partition member is shown.

[0066] As an example, the partition member 1 is formed into a thick flat plate or sheet shape. However, the partition member 1 may be formed into a shape other than a flat plate or sheet shape (bow, L-shape, semicircle, etc.) depending on the shape of the object to be partitioned by the partition member.

[0067] exist Figure 1 In the example shown in (A), the partition member 1 is formed into a flat plate having a height, a width, and a thickness, and has a thickness direction and a surface direction. The surface direction is a direction orthogonal to the thickness direction. As long as it is orthogonal to the thickness direction, the surface direction includes the height direction, the width direction, and the inclined direction of the partition member 1.

[0068] The partition member 1 is used to separate the single cells constituting the battery pack or the single cells constituting the battery pack from the components other than the single cells in the thickness direction. The partition member 1 has a plane 1a and a plane 1b on the opposite side of the plane 1a as two surfaces in the thickness direction. The plane 1a is an example of one of the two surfaces in the thickness direction, and the plane 1b is an example of the other of the two surfaces in the thickness direction. However, the plane 1a and the plane 1b may also be curved surfaces or concave-convex surfaces. The components other than the single cells are, for example, the shell of the battery pack. However, the components other than the single cells may or may not be components of the battery pack.

[0069] When the partition member 1 is disposed between the cells in the battery pack, a confining pressure in the thickness direction is applied mainly within a range of 0.1 MPa to 5 MPa, and it is desirable that when the confining pressure is applied, the thickness of the partition member 1 becomes between 95% and 30% of the thickness in a state where the confining pressure is removed. However, the setting of the confining pressure is not limited to the above value range.

[0070] The partition member 1 has therein: a fluid having a boiling point of 80° C. or higher and 250° C. or lower at normal pressure; and a flow path of the fluid extending along the surface direction of the partition member 1 .

[0071] (fluid)

[0072] "A fluid having a boiling point of 80°C to 250°C at normal pressure" is a fluid having a boiling point of 80°C to 250°C at normal pressure (1 atmosphere). The fluid is not particularly limited as long as it has the above-mentioned boiling point, and can be in the state of either liquid or gas at normal pressure. In addition, only one fluid having a boiling point of 80°C to 250°C at normal pressure (1 atmosphere) is exemplified below, but when the boiling point of one fluid is outside this temperature range and a mixture of two or more fluids is prepared and the boiling point of the mixture is within this temperature range, the mixture of the two or more fluids can also be used as the fluid in the present invention.

[0073] The fluid preferably contains, for example, at least one substance selected from the group consisting of water, alcohols, esters, ethers, ketones, hydrocarbons, fluorine compounds, and silicone oils.

[0074] Examples of alcohols that can be used for the fluid include alcohols having 3 to 8 carbon atoms such as propanol, isopropanol, butanol, benzyl alcohol, and phenylethanol, and divalent or higher alcohols such as alkylene glycols such as ethylene glycol and propylene glycol, etc. These can be used alone or as a mixture of two or more.

[0075] As esters that can be used for fluids, alkyl aliphatic carboxylates, alkyl carbonate diesters, alkyl oxalate diesters, and fatty acid esters of ethylene glycol 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 oxalate diesters, lower alkyl oxalate diesters such as dimethyl oxalate and diethyl oxalate can be cited. As ethylene glycol acetate, propyl acetate and butyl acetate can be cited. As fatty acid esters of ethylene glycol, ethylene glycol acetate can be cited. These may be used alone or as a mixture of two or more.

[0076] Examples of ethers that can be used for the fluid include n-butyl ether, n-propyl ether, isopentyl ether, etc. These may be used alone or as a mixture of two or more.

[0077] Examples of ketones that can be used for the fluid include methyl ethyl ketone, diethyl ketone, etc. These may be used alone or as a mixture of two or more.

[0078] Examples of hydrocarbons that can be used as the fluid include heptane, octane, nonane, decane, toluene, xylene, etc. These may be used alone or as a mixture of two or more.

[0079] Examples of fluorine compounds that can be used for the fluid include refrigerant 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), etc. These can be used alone or as a mixture of two or more.

[0080] Examples of silicone oils that can be used for the fluid include methylpolysiloxane, methylphenylpolysiloxane, cyclomethylsiloxane, and modified silicone oils such as silicone polyether copolymers. These may be used alone or as a mixture of two or more.

[0081] (Fluid holding part)

[0082] A fluid holding portion 11 for holding the above-mentioned fluid is provided inside the partition member 1. Figure 2 In the example shown, the fluid retaining portion 11 is formed in a flat plate or sheet shape, and the fluid retaining portion 11 is sealed by a flat plate or sheet-shaped packaging material 13. The fluid retaining portion 11 has Figure 2 A fluid flow path 12 as shown.

[0083] The fluid retaining portion 11 is formed by a material including a porous body. The porous body preferably includes at least one of a fibrous layer and a particle layer. The porous body including the fibrous layer is preferably, for example, at least one material selected from the group formed by a glass fiber sheet, a ceramic fiber sheet, paper, a cotton sheet, a porous ceramic plate, a porous glass plate, a polyimide fiber sheet, an aramid fiber sheet, and a polytetrafluoroethylene (PTFE) fiber sheet. In addition, the porous body including the particle layer is preferably, for example, at least one material selected from the group consisting of silica particles, alumina particles, zeolite particles, glass particles, and carbon particles. The entirety of the fluid retaining portion 11 can also be formed by a porous body. The thermal conductivity in the thickness direction of the fluid retaining portion when dry is preferably less than 0.5W / (mK). More preferably, it is less than 0.2W / (mK). In the following description, the case where the fluid retaining portion 11 is formed by a porous body is exemplified. The packaging material 13 contains a porous body inside.

[0084] The fluid is held by the cavities and flow paths 12 of the porous body contained in the fluid holding portion 11. For example, the fluid holding portion 11 can hold the fluid by immersing the fluid holding portion 11 in the fluid and allowing the fluid to permeate the fluid holding portion 11. Alternatively, the fluid can be introduced (filled) from the opening of the packaging material 13 containing the fluid holding portion 11 so that the fluid is contained in the fluid holding portion 11.

[0085] (Flow path)

[0086] The partition member 1 has a flow path for the fluid, which extends in the surface direction. In the present embodiment, preferably, the flow path 12 includes a space that is a continuous space with a length of more than 1 mm through which the fluid can move, and the diameter of a ball that can be inscribed in the space is more than 0.1 mm in an area that accounts for more than 90% of the volume of the space.

[0087] Figure 2 2 shows an example of the flow path 12 included in the fluid retaining portion 11. Figure 2 In the example of FIG. 1 , the flow path 12 is formed into a meandering shape by connecting the flow path extending in the height direction of the fluid retaining portion 11 (partitioning member 1) and the flow path extending in the width direction. Each end of the flow path 12 reaches the outer edge of the fluid retaining portion 11. However, the shape of the flow path forming the flow path 12 and the number of the flow paths can be appropriately set and do not necessarily have to be as Figure 2 As shown in the figure, the end of the flow path 12 reaches the outer edge of the fluid retaining portion 11. For example, it is preferred that the length of the flow path 12 in the height direction or the width direction of the partition member 1 is formed to be at least 1 / 2 of the length in the height direction or the width direction of the partition member 1. In addition, the flow path 12 does not necessarily have to be formed in a straight line, and may also be in a curved line.

[0088] The flow path 12 can be a groove formed on the surface of the fluid holding part 11, a linear hole penetrating the fluid holding part 11, or a cavity formed inside the fluid holding part 11. The flow path 12 can also be formed by machining a single member made of the material of the fluid holding part as described above. Additionally, the flow path 12 can be formed by combining the materials of multiple fluid holding parts. Since the flow path 12 is formed along the plane direction, in addition to extending in the plane direction, it may also include a direction slightly deviated from the plane direction. Thus, in the partition member 1 of the present embodiment, it is preferable that a porous body (fluid holding part 11) containing fluid is provided inside the partition member 1, and the flow path 12 is formed in the porous body.

[0089] (Packaging material)

[0090] The packaging material 13 contains the fluid holding part 11 inside and seals the fluid holding part 11 holding the fluid. As the packaging material 13, for example, a resin sheet, a resin film, a resin pouch (in Japanese: パウチ袋), etc. can be applied. For example, the fluid holding part 11 is clamped by two resin sheets or resin films or a folded resin sheet or resin film, and the fluid holding part 11 holding the fluid is sealed by heat welding or bonding of the resin sheet or resin film. However, the packaging material 13 is not essential. For example, when the fluid holding part 11 is formed of a porous material with high water absorption, etc., the fluid holding part 11 can hold the desired amount of fluid for the desired time even without the packaging material 13. Additionally, since the fluid functions as a heat transfer medium, in the fluid holding part 11, the more fluid it contains, the more heat transfer can be further promoted. Specifically, it is preferable that the fluid holding part 11 holds a fluid with a volume of 20% or more of the total volume of the volume of the flow path and the voids of the porous body, more preferably 50% or more. On the other hand, there is no particular limitation on the upper limit, and it is usually 100%.

[0091] (Battery pack)

[0092] Next, a battery pack to which a partition member 1 is applied is described. The partition member of the present embodiment includes the above-mentioned partition member. The battery pack is suitable for use in, for example, electric vehicles (EV, Electric Vehicle), hybrid electric vehicles (HEV, Hybrid Electric Vehicle), plug-in hybrid electric vehicles (PHEV, Plug-in Hybrid Electric Vehicle), electric heavy machines, electric motorcycles, electric power-assisted bicycles, ships, aircraft, electric trains, uninterruptible power supplies (UPS, Uninterruptible Power Supply), home power storage systems, and battery systems for stabilizing power systems that utilize renewable energy sources such as wind energy / solar energy / tidal energy / geothermal energy, etc. In addition, the battery pack can also be used as a power source for supplying power to devices other than the above-mentioned EV, etc.

[0093] (Single battery)

[0094] Figure 3 (A) is a plan view showing an example of a single battery (battery unit) constituting a battery pack. Figure 3 (B) is a front view showing an example of a single battery (battery unit). Figure 3 (C) is a side view showing an example of a single battery (battery unit).

[0095] The cell 2 is a rectangular parallelepiped having a longitudinal (thickness), a transverse (width), and a height, and has terminals 21 and 22 on its upper surface. The cell 2 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, nickel-hydrogen batteries, nickel-cadmium batteries, and lead storage batteries can be applied.

[0096] (Battery Pack)

[0097] Figure 4 is a plan view showing an example of a battery pack formed using a plurality of single cells, Figure 5 It means cutting along the A-A line. Figure 4 FIG. 1 is a diagram showing an end view of a battery pack case. Figure 4 In the embodiment, the battery pack 10 is formed by arranging the single cells 2 in m columns and n rows. m and n are natural numbers greater than 1. Figure 4 In the example shown, the cells 2 are arranged in two columns and five rows (m=2, n=5). In the first column, the cells 2a to 2e are arranged in the thickness direction, and in the second column, the cells 2f to 2g are arranged in the thickness direction. However, the number of columns and rows can be set appropriately. A battery pack may also be formed by arranging a plurality of cells 2 in one column.

[0098] The plurality of cells 2 constituting the arrangement are housed in a housing 3 having a bottom surface and four side surfaces. The partition member 1 is disposed between the rows of the cells 2 in the arrangement, and the cells 2 in each row are partitioned in the thickness direction of the partition member 1. For example, the cells 2a and 2f in the first row and the cells 2b and 2g in the second row are partitioned by the partition member 1X as the partition member 1. For example, the plane 1a (refer to Figure 1 (B)) is opposite to the single cell 2a and the single cell 2f, and the plane 1b is opposite to the single cell 2b and the single cell 2g. The other rows are also separated by the partition member 1 in the same manner. In this way, the length W1 ( Figure 1 (A)) is preferably longer than the length W2 in the width direction of the single cell 2 ( Figure 3 (B)).

[0099] In the present embodiment, an example is described in which the surface of the cell 2 facing the partition member 1 is in contact with the surface (plane 1a or plane 1b) in the thickness direction of the partition member 1. However, the cell 2 may be in contact with the partition member 1 via a protrusion, a contact point, etc. formed on at least one of the cell 2 and the partition member 1, or may be arranged in a state separated from the partition member 1 by a member other than the partition member 1.

[0100] In addition, for the cells 2a to 2e and the cells 2f to 2j, the positive terminals (e.g., terminals 21) and the negative terminals (e.g., terminals 22) of the adjacent cells 2 are electrically connected in series via the bus bar 4. The cells 2a to 2e and the cells 2f to 2j are connected in series, for example, to output a predetermined amount of power.

[0101] The housing 3 accommodates the single cells 2 constituting the battery pack 10. Figure 5 As shown, a partition member 1A is arranged between the bottom surface of the shell 3 and each of the single cells 2 arranged in a row. The partition member 1A has the same structure as the partition member 1. The bottom surface (bottom wall) of the shell 3 is an example of a member other than a single cell. In addition, a partition member 1 may be arranged between the single cell 2 and the side wall of the shell 3. In addition, instead of the shell 3, a common end plate may be used to clamp each column of the plurality of single cells 2 arranged in a row, and the battery pack may be integrated by fastening them with a connecting member. In addition, in Figure 4 In the embodiment, for example, at least one of the cells 2a to 2e may be a member other than a cell.

[0102] <Function of partition member>

[0103] Figure 6This is a diagram for explaining the function of the partition member 1. The battery pack may become locally hot due to micro short circuit of the single cell 2, heat generation of the terminal portion (terminal 21, terminal 22), etc. Among the local high temperatures, there are cases where one of the multiple single cells arranged in a row reaches a high temperature (first case) and cases where a local high temperature portion is generated in one single cell 2 (second case).

[0104] Figure 6 (A) schematically shows the first case. For example, in the partition member 1 (1X: see Figure 4 ) at the position where the entire single cell 2a reaches abnormal heating.

[0105] Figure 6 (B) schematically shows the second situation. For example, in the partition member 1 (1X: see Figure 4 ) at the position where the local portion 2A of the single cell 2 (single cell 2a) facing the plane 1a reaches abnormal heating.

[0106] Regardless of the first or second situation, if Figure 6 As shown in (C), the fluid retained by the fluid retaining portion 11 in the area opposite to the high temperature portion of the single cell 2 (single cell 2a, portion 2A) receives heat from the high temperature portion and vaporizes. The vaporized fluid mainly moves in the flow path 12 and moves to a portion not opposite to the high temperature portion with heat. Since the temperature of the portion not opposite to the high temperature portion is lower than that of the high temperature portion, the vaporized fluid condenses and becomes liquid again. The fluid that has become liquid moves to the high temperature portion mainly through the flow path 12 together with latent heat. By circulating the fluid accompanied by such movement of the fluid in the surface direction, the heat of the high temperature portion is transported and the high temperature portion is cooled.

[0107] The fluid moves from the high temperature portion to the low temperature portion under the capillary phenomenon through the pores of the porous body. However, in this embodiment, by forming a flow path 12 that is larger than the space of the porous body along the surface direction, the fluid gathered in the flow path 12 can smoothly move in the surface direction through the flow path 12. That is, by forming the flow path 12, the movement of the high temperature fluid in the surface direction can be promoted.

[0108] Alternatively, as the fluid expands due to gasification or as the temperature rises, an opening is formed in the packaging material 13, and the fluid flows out from there (see Figure 6 (C) of the figure mark 5). By discharging the fluid from the opening, heat removal can be promoted. In addition, since the opening can be formed, the interior of the partition member becomes normal pressure, which can promote heat transfer based on the volume expansion of the gas phase generated by boiling of the fluid under normal pressure and the cooling effect based on the latent heat of evaporation.

[0109] In addition, when the fluid retaining portion 11 retains a liquid fluid, the fluid becomes a medium for transferring heat from the single cell 2 and has a predetermined thermal conductivity in the thickness direction of the partition member 1. On the other hand, when the fluid vaporizes, the thermal conductivity of the portion of the fluid retaining portion 11 where the vaporized fluid exists decreases, and the portion functions as a heat insulating layer.

[0110] Through the above-mentioned heat transfer in the surface direction and the thermal insulation layer formed as the fluid vaporizes, more heat moves in the surface direction than in the thickness direction, thereby suppressing the heat transfer to the single cell 2 (2b) opposite to the abnormally heated single cell 2 (2a) separated by the partition member 1 (1X), thereby preventing the single cell 2b from becoming abnormally heated.

[0111] Figure 7 The first case is schematically shown. Figure 7 (A) shows a state in which the battery pack is assumed to be in normal operation. The cells 2a and 2f and the cells 2b and 2g are separated by the separation member 1X.

[0112] Figure 7 The partition member 1 (1X) illustrated in (A) has the following structure. That is, preferably, one of the two faces in the thickness direction of the partition member has a first region facing the first cell in the battery pack and a second region not facing the first cell, and the one face faces at least one of a second cell different from the first cell in the battery pack and a member other than the cell in the second region.

[0113] exist Figure 7 In (A), the plane 1b of the partition member 1X corresponds to "one of the two surfaces in the thickness direction of the partition member". The area 1c in the plane 1b opposite to the single cell 2g separated by the partition member 1X corresponds to the "first area opposite to the first single cell in the battery pack", and the single cell 2g corresponds to the "first single cell". On the other hand, the area 1d in the plane 1b not opposite to the single cell 2g corresponds to the "second area not opposite to the first single cell". And, the single cell 2b opposite to the area 1d corresponds to the "second single cell different from the first single cell in the battery pack". Instead of the single cell 2b, a member other than the single cell may be opposite to the area 1d, or a member other than the single cell may be opposite to the area 1d together with the single cell 2b.

[0114] In addition, if Figure 7The partition member 1 (1X) illustrated in (A) has the following structure. That is, it is preferred that the other of the two faces in the thickness direction of the partition member is opposite to at least one of a third cell that is different from the first cell and the second cell and is not opposite to the first cell across the partition member and a member other than the cell in the battery pack.

[0115] exist Figure 7 In (A), the plane 1a of the partition member 1X corresponds to "the other of the two surfaces in the thickness direction of the partition member". The single cell 2a facing the plane 1a corresponds to "the third single cell which is different from the first single cell and the second single cell and is not facing the first single cell across the partition member". Instead of the single cell 2a, a member other than the single cell may face the region 1d, or a member other than the single cell may face the region 1d together with the single cell 2a.

[0116] Under normal circumstances (at room temperature), Figure 7 As shown in (A), the liquid fluid is evenly distributed in the fluid retaining portion 11. Therefore, the partition member 1X has a desired thermal conductivity between the cells 2 facing each other across the partition member 1X (between the cells 2a and 2b, and between the cells 2f and 2g).

[0117] like Figure 7 As shown in (B), it is assumed that the cell 2g becomes abnormally heated. In this case, the fluid existing in the portion of the fluid retaining portion 11 corresponding to the region 1c facing the cell 2g is vaporized, and the vaporized fluid moves along the surface direction of the partition member 1X with the heat (see Figure 7 In addition, the fluid located at the position corresponding to the region 1c and not vaporized on the plane 1a side suppresses the transfer of heat to the cell 2 (also referred to as the "cell 2 on the opposite side") opposite to the cell 2g via the partition member 1X, that is, the cell 2f, thereby suppressing the heat rise of the cell 2f (see Figure 7 ) of (B) with reference numeral (2)).

[0118] When the temperature of the cell 2b facing the area 1d of the plane 1b and the temperature of the cell 2a facing the plane 1a, which is the cell 2 on the opposite side of the cell 2b, are not abnormally heated (lower than abnormally heated or at room temperature), the cell 2b and the cell 2a function as a heat sink and receive heat from the partition member 1X (see Figure 7 As a result, the gasified fluid in the fluid retaining portion 11 is condensed and restored to liquid, and is returned to the high temperature portion side. That is, the fluid circulates in the partition member 1X (fluid retaining portion 11).

[0119] like Figure 7 As shown in (C), it is assumed that the vaporized fluid is released from the partition member 1X and the fluid retaining portion 11 becomes a fluid or air containing gas. In this case, the air (fluid in gas phase) contained in the fluid retaining portion 11 forms a heat insulating layer, and the heat transfer coefficient of heat transfer to the battery 2f on the opposite side is reduced. Therefore, it is possible to avoid the battery 2f receiving heat from the battery 2g and causing abnormal heating.

[0120] Figure 8 The second case is schematically shown. Figure 8 (A) shows a state in which the battery pack is assumed to be in normal operation. The cells 2a and 2f and the cells 2b and 2g are separated by the separation member 1X.

[0121] Under normal circumstances (at room temperature), Figure 8 As shown in (A), the liquid fluid is uniformly distributed in the fluid retaining portion 11. Therefore, the partition member 1X has a desired thermal conductivity between the cells 2 (between the cells 2a and 2b) facing each other across the partition member 1X.

[0122] like Figure 8 As shown in (B), it is assumed that the single cell 2b becomes locally abnormally heated. In this case, the local high temperature portion ( Figure 8 The fluid existing in the portion opposite to the reference numeral 7 in (B) is vaporized, and the vaporized fluid moves along the surface direction of the partition member 1X (each end side in the width direction of the partition member 1X) with heat (refer to Figure 8 In addition, the fluid located at the position corresponding to the high temperature portion 7 and located on the plane 1a side and not vaporized suppresses the transfer of heat to the cell 2a on the opposite side of the cell 2b, thereby suppressing the heat rise of the cell 2a (see Figure 7 ) of (B) with reference numeral (2)).

[0123] In the portion of the fluid retaining portion 11 that is not facing the high temperature portion 7, the fluid is in a liquid state and normally maintains a heat transfer coefficient for transferring heat to the nearby single cell 2a. Thus, the single cell 2a functions as a radiator, receiving heat transferred from the high temperature portion 7 (see Figure 8 As a result, the gasified fluid in the fluid retaining portion 11 is condensed and restored to liquid, and is returned to the high temperature portion 7 side. That is, the fluid circulates in the partition member 1X (fluid retaining portion 11).

[0124] like Figure 8As shown in (C), when the gasified fluid is released from the partition member 1X and the fluid holding portion 11 becomes a state containing a fluid or air as a gas, as shown in FIG. Figure 7 As described in (C), the fluid retaining portion 11 functions as a heat insulating layer, and the heat transfer coefficient to the opposite battery cell 2a is reduced. Therefore, it is possible to avoid the battery cell 2a receiving heat from the battery cell 2b and becoming abnormally heated.

[0125] Fig. 9 and Fig.10 Indicated in Figure 4 In the battery pack 10 shown in FIG. 1 , the single cell 2b becomes a heat transfer path in the case of abnormal heat generation. When abnormal heat is generated in the upper part of the single cell 2b, as shown in FIG. Fig. 9 As shown, the fluid contained in the fluid retaining portion 11 of the partition member 1 facing the high temperature portion 7 is vaporized, and the thermal conductivity of the portions of the partition member 1X and the partition member 1Y where the fluid is vaporized becomes high. Therefore, it is possible to suppress the movement of heat from the heat generating portion of the single cell 2b toward the single cell 2a and the single cell 2c in the thickness direction of the partition member 1 as shown by the dotted arrow A.

[0126] On the other hand, the fluid that has been vaporized by receiving the heat from the high temperature portion 7 moves mainly in the surface direction (height direction) through the flow path 12, thereby moving to the lower part of the fluid retaining portion 11 possessed by both the partition member 1X and the partition member 1Y. In the lower part of the fluid retaining portion 11, the fluid is in a liquid phase, and therefore, its thermal conductivity with both the single cell 2a and the single cell 2c corresponding to the single cell 2 on the opposite side is maintained in a state close to that in the normal state. Therefore, the heat that has moved to the lower part of the fluid retaining portion 11 of both the partition member 1X and the partition member 1Y can move in the thickness direction and be transferred to the opposite single cell 2a and the single cell 2c. The heat that has moved to the single cell 2c can be further transported to the single cell 2d side via the partition member (see the solid arrow B).

[0127] In addition, the heat moved to the lower part of the fluid retaining part 11 of both the partition member 1X and the partition member 1Y is transferred to the partition member 1A and moves along the surface direction of the partition member 1A. At this time, mainly the bottom wall of the housing 3 functions as a radiator and can receive the heat from the partition member 1A. And, as shown by the solid arrow D, the heat moved to the bottom of the housing 3 is dissipated to the outside.

[0128] exist Fig.10In the figure, heat transfer from the high temperature portion 7 of the single cell 2b to the direction indicated by the dotted arrow E is suppressed by the partition member 1X and the partition member 1Y. On the other hand, the heat from the high temperature portion 7 moves along the surface direction (width direction) of the partition member 1X and the partition member 1Y (see arrow G). The single cell 2f, the single cell 2g, and the single cell 2h function as radiators and can receive heat from the partition member 1X and the partition member 1Y. Cooling is performed by the circulation of the fluid in the partition member 1X and the partition member 1Y. When the fluid is basically vaporized or the fluid is discharged to the outside of the partition member 1X, the fluid retaining portion 11 functions as a heat insulating layer, thereby suppressing the transfer of heat to the single cell on the opposite side.

[0129] According to the partition member 1 and the battery pack 10 described above, when the battery pack 10 generates abnormal heat locally, the abnormally heated portion can be safely cooled without causing thermal runaway of the cells 2 constituting the battery pack 10 .

[0130] Fig.11 This embodiment ( Figure 4 ) Modification 1. In this embodiment, a structure example is shown in which one partition member 1 is used to partition the rows of cells 2 in the column direction (a partition member 1 facing two cells 2 is inserted between the rows). Alternatively, such a structure may be used. Fig.11 As shown on the left side of FIG. 1 , the partition members arranged between the rows are composed of a partition member 51 having a width direction length shorter than the width direction length W1 of the single cell 2 and each surface in the thickness direction facing one single cell 2, and a partition member 52 arranged so as to straddle between two single cells. The partition members 51 and 52 have the same structure as the partition member 1 except that the width direction lengths are different.

[0131] like Fig.11 As shown on the right side of FIG. 1 , in Modification 1, for the abnormal heating of the local part in the single cell 2 such as the high temperature part 7a and the high temperature part 7b, it is possible to utilize the use of Figure 8 The second situation described above moves the heat. In addition, for the abnormal heating of a part of the single cell 2 such as the high temperature part 7c, the use of Figure 7 The heat is transferred by the action in the first case described.

[0132] Fig.12 Indicates the implementation method ( Figure 4 ) Modification 2. In this embodiment, a structure example is shown in which one partition member 1 is used to partition the rows of the single cells 2 in the column direction (a partition member 1 facing two single cells 2 is inserted between the rows). Alternatively, such a structure may be used. Fig.12As shown on the left side of FIG. 1 , the partition members arranged between the rows are divided into partition members 53 for partitioning the cells 2 in each column. The partition members 53 have the same structure as the partition members 1 except that the length in the width direction is different.

[0133] like Fig.12 As shown on the right side of FIG. 1 , in the second modification, the abnormal heating of the local part of the single cell 2 such as the high temperature part 7d and the high temperature part 7e can be utilized by using Figure 8 The action in the second case described is to transfer heat.

[0134] Example

[0135] Next, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0136] (Example 1)

[0137] As the fluid retaining portion 11 of the partition member 1, a cellulose fiber filter paper (model No. 590, thickness 0.93 mm) produced by ADVANTEC Toyo Co., Ltd. was cut into a size of 50 mm in length and 110 mm in width. Then, a cut was made on the filter paper (fluid retaining portion 11, hereinafter also referred to as filter paper 11) as shown in FIG. Figure 2 Thus, a flow path 12 with a width of 1 mm was prepared in a meandering shape by connecting a flow path extending in the height direction of the filter paper 11 and a flow path extending in the width direction. Figure 1 Then, 6 g of water was impregnated into the filter paper 11 to prepare the partition member 1 ( Figure 1 (A)), the bag is made by folding a 60 μm thick PET sheet (packaging material 13, hereinafter also referred to as sheet 13) in half. Fig.13 (A) and Fig.13 As shown in (B), the heater 30, aluminum plate 31, buffer 32A (porous zirconia plate made by Hashimoto Riken Industry Co., Ltd. with a porosity of 22%), aluminum plate 31, aluminum foil 33 (thickness 11μm), partition member 1, aluminum foil 33 (thickness 11μm), aluminum plate 31, buffer 32B (same material as buffer 32A), aluminum plate 31, radiator 34A (comb-shaped radiator made of aluminum, 120mm×120mm×30mm) are arranged in this order so that the left 50mm portion of the partition member 1 is clamped and the components are closely attached. In addition, as Fig.13 (A) and Fig.13 As shown in (B), the right 50 mm portion of the same partition member is sandwiched by a heat sink 34B and a heat sink 34C (plate-type heat sink 170 mm×100 mm×15 mm) made of aluminum.

[0138] Here, the heater 30 corresponds to a cell or a part of a cell that has become abnormally heated due to micro-short circuit of the cell 2, heating of the terminal portion (terminal 21, terminal 22), etc. in the battery pack. In addition, the heat sinks 34A, 34B, and 34C are cells or parts of cells that are lower than the temperature of abnormal heating or at room temperature, and correspond to cells or parts of cells that receive heat from the cell or part of cells that have become abnormally heated, or to members other than cells that constitute the battery pack. In addition, the thermal conductivity of the aluminum plate 31 and the aluminum foil 33 is higher than the thermal conductivity of the members that constitute the cell 2. In order to timely measure the surface temperature of the heater 30, the filter paper 11, and the heat sink 34A facing each other, the aluminum plate 31 and the aluminum foil 33 are arranged on each surface. The buffer 32A and the buffer 32B suppress the temperature of the heater 30, the filter paper 11, and the heat sink 34A facing each other from being thermally transferred to the facing surface. In order to measure each separately, the buffer 32A and the buffer 32B are arranged between each surface.

[0139] In this state, the heater 30 was heated to 450°C in the atmosphere at room temperature. After the temperature of the heater 30 reached 450°C, the heating was continued for 1 hour. The temperature change at each position was measured from the start of heating by the heater 30 to the end of heating. The results are shown in Fig.14 .

[0140] The heat flux flowing in each zirconia plate is calculated based on the temperature difference between the high temperature side and the low temperature side of the buffer 32A and buffer 32B (zirconia plate) provided on the left and right sides of the partition member 1 and the thermal conductivity of the zirconia plate. Thus, the heat flux moving from the heater 30 side to the partition member, the heat flux moving from the partition member 1 to the radiator 34A, and the heat flux moving from the heater 30 to the radiator 34B and the radiator 34C via the partition member are calculated according to the following formulas.

[0141] Q1=A1×k1×ΔT1 / L1

[0142] Q2=A2×k2×ΔT2 / L2

[0143] Q3=Q1-Q2

[0144] Q1: Heat flow from the heater 30 side to the partition member 1 (W)

[0145] Q2: Heat flow from the partition member 1 to the heat sink 34A (W)

[0146] Q3: Total heat flow rate transferred from the heater 30 to the heat sink 34B and the heat sink 34C via the partition member (W)

[0147] A1: The projected area of ​​the buffer 32A in the direction from the heater 30 to the radiator 34A is 0.0025 (m 2 )

[0148] A2: The projected area of ​​the buffer 32B in the direction from the heater 30 toward the radiator 34A is 0.0025 (m 2 )

[0149] k1: Thermal conductivity of buffer 32A 0.93 (W / (mK))

[0150] k2: Thermal conductivity of buffer 32B 0.93 (W / (mK))

[0151] ΔT1: Temperature difference between the high temperature side surface and the low temperature side surface of the buffer 32A (K)

[0152] ΔT2: Temperature difference between the high temperature side surface and the low temperature side surface of the buffer 32B (K)

[0153] L1: Thickness of sensor 32A 0.005 (m)

[0154] L2: Thickness of buffer 32B 0.005 (m)

[0155] The heat flow rate of the heater 30 after reaching 450° C. and 10 minutes later was as follows.

[0156] Heat flow from the heater 30 side to the partition member 124W

[0157] Heat flow rate from the partition member 1 to the heat sink 34A is 20 W

[0158] Heat flow rate (total) from the partition member 1 to the heat sink 34B and the heat sink 34C: 104 W

[0159] Until the heating of the heater 30 is completed, the temperature of the low temperature side of the partition member 1 is maintained at less than 100° C. That is, it is shown that, among the heat generated by the heater 30, the heat flow moving toward the heat sinks 34B and 34C along the surface direction of the partition member 1 is greater than the heat flow moving toward the heat sink 34A along the thickness direction of the partition member 1.

[0160] (Comparative Example 1)

[0161] The same experiment as in Example 1 was carried out without forming the flow path 12 on the filter paper 11. The measured temperature change is shown in FIG. Fig.15 .

[0162] The heat flow rate of the heater 30 after reaching 450° C. and 10 minutes later was as follows.

[0163] Heat flow from the heater 30 to the partition member 1 is 61 W

[0164] Heat flow rate 43W from the partition member 1 to the heat sink 34A

[0165] Heat flow rate from the partition member 1 to the heat sink 34B and the heat sink 34C (total) 17W

[0166] After the temperature of the heater 30 reached 450° C. and 7 minutes and 40 seconds later, the temperature of the low temperature side of the partition member 1 reached 150° C. That is, it is shown that, among the heat generated by the heater 30, the heat flux moving toward the heat sink 34A along the thickness direction of the partition member 1 is greater than the heat flux moving toward the heat sinks 34B and 34C along the surface direction of the partition member 1.

[0167] (Comparative Example 2)

[0168] The same experiment as in Example 1 was carried out without forming the flow path 12 on the filter paper 11 and without water impregnation. The measured temperature change is shown in FIG. Fig.16 .

[0169] The heat flow rate of the heater 30 after reaching 450° C. and 10 minutes later was as follows.

[0170] Heat flow from the heater 30 side to the partition member 1: 56 W

[0171] Heat flux from the partition member 1 to the heat sink 34A: 50 W

[0172] Heat flow rate (total) from the partition member 1 to the heat sink 34B and the heat sink 34C: 6W

[0173] After the temperature of the heater 30 reached 450°C and 2 minutes and 40 seconds had passed, the temperature of the low temperature side of the partition member 1 reached 150°C.

[0174] (Example 2)

[0175] Experiment 1: Two 0.44 mm thick glass fiber sheets (model: GA-100) manufactured by ADVANTEC Toyo Co., Ltd. were stacked as filter paper, and the width of the flow path 12 was set to 2 mm. The same experiment as in Example 1 was carried out under these conditions. The measured temperature change is shown in FIG. Fig.17 .

[0176] The heat flow rate of the heater 30 after reaching 450° C. and 10 minutes later was as follows.

[0177] Heat flow from the heater 30 side to the partition member 1 128W

[0178] The heat flux from the partition member 1 to the heat sink 34A is 24W.

[0179] Heat flow rate (total) from the partition member 1 to the heat sink 34B and the heat sink 34C: 104 W

[0180] The temperature of the low temperature side of the partition member 1 is maintained at approximately 100° C. until the heating by the heater 30 is completed.

[0181] (Example 3)

[0182] Experiment 1: The same experiment as in Example 1 was conducted under the following conditions, except that the filter paper 11 was a ceramic fiber sheet with a thickness of 1.0 mm (model: Fiberglass PP TOMBO 5130-T) manufactured by NEXUS Corporation, and the PET sheet 13 was an aluminum-laminated PET sheet (model: D-EL40H-200) manufactured by Dai Nippon Printing Co., Ltd. The measured temperature changes are shown in FIG. Fig.18 .

[0183] The heat flow rate of the heater 30 after reaching 450° C. and 10 minutes later was as follows.

[0184] The heat flux from the heater 30 to the partition member 1 is 131 W.

[0185] Heat flow rate from the partition member 1 to the heat sink 34A is 27W

[0186] Heat flow rate (total) from the partition member 1 to the heat sink 34B and the heat sink 34C: 104 W

[0187] The temperature of the low temperature side of the partition member 1 is maintained at less than 120° C. until the heating by the heater 30 is completed.

Claims

1. A partition member having a thickness direction and a plane direction orthogonal to the thickness direction, and partitioning between single cells constituting a battery pack or between single cells constituting the battery pack and members other than the single cells in the thickness direction, wherein the partition member is characterized in that: The device has a fluid having a boiling point of 80° C. or higher and 250° C. or lower under normal pressure, and a flow path of the fluid extending in the direction of the surface. The fluid is held by the fluid holding portion, and the fluid holding portion is sealed by a packaging material.

2. A partition member having a thickness direction and a plane direction orthogonal to the thickness direction, and partitioning between single cells constituting a battery pack or between single cells constituting the battery pack and members other than the single cells in the thickness direction, wherein the partition member is characterized in that: The fluid retaining portion includes: a fluid retaining portion capable of retaining a fluid having a boiling point of 80° C. or higher and 250° C. or lower under normal pressure; and a flow path for the fluid extending along the surface direction, wherein the fluid retaining portion is sealed by a packaging material.

3. The partition member according to claim 1 or 2, wherein: The flow path includes a continuous space having a length of 1 mm or more through which the fluid can move, and a diameter of a sphere that can be inscribed in the space is 0.1 mm or more in a region that accounts for 90% or more of the volume of the space.

4. The partition member according to claim 1 or 2, wherein: The fluid includes at least one substance selected from the group consisting of water, alcohols, esters, ethers, ketones, hydrocarbons, fluorine compounds, and silicone oils.

5. The partition member according to claim 1 or 2, wherein: A porous body capable of containing the fluid is provided inside the partition member, The flow path is formed in the porous body.

6. The partition member according to claim 5, wherein: The porous body includes at least one of a fibrous layer and a particle layer.

7. The partition member according to claim 6, wherein: The porous body includes a fibrous layer, and the porous body is at least one material selected from the group consisting of glass fiber sheets, ceramic fiber sheets, paper, cotton sheets, porous ceramic plates, porous glass plates, polyimide fiber sheets, aramid fiber sheets, and polytetrafluoroethylene fiber sheets.

8. The partition member according to claim 6 or 7, wherein: The porous body includes a particle layer, and the porous body is at least one material selected from the group consisting of silica particles, alumina particles, zeolite particles, glass particles, and carbon particles.

9. The partition member according to claim 1 or 2, wherein: The length of the flow path in the height direction or the width direction of the partition member is equal to or greater than 1 / 2 of the length of the partition member in the height direction or the width direction.

10. The partition member according to claim 1 or 2, wherein: The partition member includes the packaging material, and the packaging material includes the porous body therein.

11. A battery pack, wherein: This battery pack includes the partition member according to any one of claims 1 to 10.

12. The battery pack according to claim 11, wherein: The surface direction of the partition member includes the width direction of the partition member. The length of the partition member in the width direction is longer than the length of the single cells partitioned by the partition member in the width direction.

13. The battery pack according to claim 11 or 12, wherein: One of the two surfaces in the thickness direction of the partition member has a first region facing a first single cell in the battery pack and a second region not facing the first single cell, and in the second region, the partition member faces a second single cell in the battery pack that is different from the first single cell and at least one of a member other than the single cell.

14. The battery pack according to claim 13, wherein: The other of the two surfaces of the partition member in the thickness direction faces at least one of a third cell that is different from the first cell and the second cell and is not opposite to the first cell across the partition member, and a member other than the cell in the battery pack.

15. The battery pack according to claim 11, wherein: One of the two surfaces of the partition member in the thickness direction is opposite to the first single cell among the plurality of single cells, and the other of the two surfaces of the partition member in the thickness direction is opposite to a single cell in the battery pack that is different from the first single cell and is not opposite to the first single cell across the partition member, and at least one of a member other than the single cell in the battery pack.

16. A partition member having a thickness direction and a plane direction orthogonal to the thickness direction, and partitioning between single cells constituting a battery pack or between single cells constituting the battery pack and members other than the single cells in the thickness direction, wherein: The partition member has a fluid holding portion inside, the fluid holding portion can hold a fluid having a boiling point of 80° C. or more and 250° C. or less under normal pressure, and the fluid holding portion is contained inside by a packaging material. The packaging material comprises aluminum.

17. A method for controlling heat transfer, the method for controlling heat transfer being performed by using a partition member, the partition member having a thickness direction and a surface direction orthogonal to the thickness direction, and partitioning between single cells constituting a battery pack or between single cells constituting the battery pack and members other than the single cells in the thickness direction, the method for controlling heat transfer being characterized in that: The partition member has a fluid holding portion inside, the fluid holding portion can hold a fluid having a boiling point of 80° C. or more and 250° C. or less under normal pressure, and the fluid holding portion is contained inside by a packaging material. The heat flux moving toward the other cells along the surface direction of the partition member is greater than the heat flux moving toward the other cells along the thickness direction of the partition member.

18. The method for controlling heat transfer according to claim 17, wherein: The fluid is vaporized, and a portion of the fluid retaining portion where the vaporized fluid exists is caused to function as a heat insulating layer.

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