WO2019225643A1

WO2019225643A1 - Heat transfer suppression sheet for battery pack, and battery pack

Info

Publication number: WO2019225643A1
Application number: PCT/JP2019/020257
Authority: WO
Inventors: 直己高橋; 寿安藤; 清成畑中
Original assignee: イビデン株式会社
Priority date: 2018-05-22
Filing date: 2019-05-22
Publication date: 2019-11-28
Also published as: JP7115906B2; JP2019204636A

Abstract

A heat transfer suppression sheet for a battery pack is provided with which, when the battery pack is constituted from a plurality of battery cells connected in series or in parallel, it is possible to effectively cool the battery cells during normal use, while suppressing the propagation of heat among the battery cells during abnormal use. A heat transfer suppression sheet used in a battery pack in which a plurality of battery cells is disposed with the heat transfer suppression sheet interposed therebetween, the plurality of battery cells being connected in series or in parallel, wherein the heat transfer suppression sheet is characterized by having a heat transfer suppression layer containing inorganic particles and or inorganic fibers, and having a grooved section communicating with the end faces in the in-plane direction of the heat transfer suppression layer, the surface of the grooved section having a concave/convex shape.

Description

Heat transfer suppression sheet for assembled battery and assembled battery

The present invention relates to an assembled battery heat transfer suppression sheet that is preferably used for an assembled battery that serves as a power source for an electric motor that drives an electric vehicle or a hybrid vehicle, for example.

In recent years, development of electric vehicles or hybrid vehicles driven by electric motors has been actively promoted from the viewpoint of environmental protection. In this electric vehicle or hybrid vehicle, an assembled battery in which a plurality of battery cells are connected in series or in parallel to serve as a power source for a driving electric motor is mounted.

Compared to lead-acid batteries and nickel-metal hydride batteries, this battery cell mainly uses lithium-ion secondary batteries capable of high capacity and high output, but due to internal short circuit or overcharge of the batteries. When a thermal runaway occurs in one battery cell (that is, in an abnormal state), heat may propagate to other adjacent battery cells, which may cause thermal runaway of other battery cells.

As a technique for suppressing the propagation of the thermal runaway as described above, Patent Document 1 discloses a first plate member disposed on the side of a first power storage element that is one of one or more power storage elements, and a first plate material. A first plate member and a second plate member disposed so that the surfaces of the two plate members are opposed to each other, between the first plate member and the second plate member, more heat than the first plate member and the second plate member; It is disclosed that an effective heat insulation between a power storage element and another object can be realized by a power storage device in which a low thermal conductive layer (for example, an air layer) that is a layer of a material having low conductivity is formed. ing.

In addition, as another technique for suppressing the propagation of thermal runaway, Patent Document 2 discloses that a heat insulating buffer member is disposed between stacked battery cells, so that one of a plurality of battery cells is disposed. Even when a thermal abnormality occurs in the battery cells, thermal insulation can be achieved between the battery cells, and the phenomenon that the thermal abnormality is chained to other battery cells can be suppressed. It is disclosed.

Japanese Unexamined Patent Publication No. 2015-211013 Japanese Unexamined Patent Publication No. 2009-163932

On the other hand, in the case where a charge / discharge cycle is performed on an assembled battery cell (that is, during normal use), in order to fully demonstrate the charge / discharge performance of the battery cell, the temperature of the battery cell surface is a predetermined value or less ( For example, it is necessary to maintain at 150 ° C. or lower.

However, in Patent Document 1, since a heat insulating layer is simply provided between a plurality of battery cells in order to suppress heat propagation during thermal runaway, it is possible to effectively cool battery cells that generate heat during normal use. could not.
Further, in Patent Document 2, by forming irregularities on the surface of the heat insulating buffer member, heat insulation can be achieved between the battery cells, and at the time of stacking the battery cells, there can be a ventilation effect by this groove, Since the heat insulating cushioning member is made of a sheet made of polycarbonate resin or polypropylene resin, when a groove is provided in this sheet, it cannot be said that it is sufficient to cool battery cells that generate heat during normal use, as will be described later. It was.

The present invention has been made paying attention to such a situation, and suppresses the propagation of heat between the battery cells at the time of abnormality in constituting an assembled battery in which a plurality of battery cells are connected in series or in parallel. However, it aims at providing the heat transfer suppression sheet | seat for assembled batteries which can cool the battery cell at the time of normal use effectively.

In order to achieve the above object, the summary of the heat transfer suppression sheet for assembled batteries according to one aspect of the present invention is that a plurality of battery cells are arranged via a heat transfer suppression sheet, and the plurality of battery cells are connected in series or in parallel. A heat transfer suppression sheet used for a connected assembled battery, having a heat transfer suppression layer containing inorganic particles and / or inorganic fibers, wherein the heat transfer suppression layer is in an in-plane direction of the heat transfer suppression layer It has the groove part connected to this end surface, The surface of the said groove part has uneven | corrugated shape, It is characterized by the above-mentioned.

In a preferred embodiment of the assembled battery heat transfer suppression sheet, the groove portion communicates one end surface with the other end surface.
In a preferred embodiment of the assembled battery heat transfer suppressing sheet, the heat transfer suppressing layer has a quadrangular outer shape in plan view, and the groove portion communicates two adjacent end surfaces among the four end surfaces. To do.

In a preferred embodiment of the assembled battery heat transfer suppressing sheet, the heat transfer suppressing layer contains the inorganic particles as an essential component, and the inorganic particles are made of a material that releases moisture by heating.
In a preferred embodiment of the heat transfer suppressing sheet for assembled batteries, the material that releases moisture by heating can be dehydrated at an inorganic hydrate having a thermal decomposition starting temperature of 200 ° C. or higher and / or a temperature of 150 ° C. or lower. A dehydrating agent.
In a preferred embodiment of the assembled battery heat transfer suppression sheet, the water-releasing material contains the inorganic hydrate as an essential component, and the inorganic hydrate includes aluminum hydroxide, magnesium hydroxide, hydroxide. It is at least one selected from the group consisting of calcium, zinc hydroxide, iron hydroxide, manganese hydroxide, zirconium hydroxide and gallium hydroxide.
In a preferred embodiment of the assembled battery heat transfer suppression sheet, the moisture releasing material contains the dehydrating agent as an essential component, and the dehydrating agent includes silica gel, activated alumina, activated carbon, zeolite, ion exchange resin, sulfuric acid. It is at least one of the group consisting of salt hydrate, sulfite hydrate, phosphate hydrate, nitrate hydrate, acetate hydrate and metal hydrate.

In a preferred embodiment of the assembled battery heat transfer suppressing sheet, the heat transfer suppressing layer contains the inorganic fiber as an essential component, and the inorganic fiber includes silica-alumina fiber, alumina fiber, silica fiber, rock wool, alkali. It is at least one selected from the group consisting of earth silicate fibers and glass fibers.
In a preferred embodiment of the assembled battery heat transfer suppression sheet, the heat transfer suppression layer contains the inorganic particles as an essential component, and the inorganic particles are at least one of the group consisting of TiO ₂ and SiO _2. .

In a preferred embodiment of the assembled battery heat transfer suppressing sheet, the heat transfer suppressing layer is formed on both surfaces of the heat insulating layer containing the inorganic particles and / or the inorganic fibers and the heat insulating layer. A heat-absorbing layer containing a material that emits heat.

The gist of the assembled battery according to one embodiment of the present invention is that a plurality of battery cells are arranged via the above-described assembled battery heat transfer suppression sheet, and the plurality of battery cells are connected in series or in parallel. It is characterized by.

According to the heat transfer suppression sheet for an assembled battery according to the present invention, in configuring an assembled battery in which a plurality of battery cells are connected in series or in parallel, while suppressing the propagation of heat between the battery cells during an abnormality, It is possible to provide an assembled battery heat transfer suppressing sheet capable of effectively cooling battery cells during use.

FIG. 1 is a diagram schematically illustrating a configuration example of a heat transfer suppression sheet for an assembled battery according to the first embodiment of the present invention, and is an example in a case where the heat transfer suppression layer includes lattice-shaped grooves. . FIG. 2 is an enlarged view of the uneven shape of the groove in FIG. FIG. 3A is a diagram illustrating an example in which the heat transfer suppression layer has a lattice-shaped groove portion in which corner portions are R-processed. FIG. 3B is a diagram illustrating an example in which the heat transfer suppression layer has a groove portion having a labyrinth structure. FIG. 3C is a diagram illustrating an example in which the heat transfer suppressing layer has a groove portion having an embossed structure having a planar circular shape. FIG. 3D is a diagram illustrating an example in which the heat transfer suppression layer has a groove portion having a honeycomb structure. FIG. 3E is a diagram illustrating an example in the case where the heat transfer suppression layer includes a square-convex convex groove. FIG. 3E is a diagram illustrating an example in which the heat transfer suppression layer has a rectangular concavity groove. FIG. 3G is a diagram illustrating an example in which the heat transfer suppression layer has a corrugated groove. FIG. 4 is a cross-sectional view schematically showing a configuration example of an assembled battery to which the assembled battery heat transfer suppression sheet according to the first embodiment of the present invention is applied. FIG. 5 is a diagram schematically illustrating a configuration example of a heat transfer suppression sheet for an assembled battery according to the second embodiment of the present invention, in which a heat transfer suppression layer includes a heat insulating layer and an endothermic layer formed on both surfaces thereof. It is an example in the case of being configured. FIG. 6A is a diagram illustrating a manufacturing example in the case where grooves are formed on the upper and lower surfaces of the heat transfer suppression layer by two embossing rollers. FIG. 6B is a diagram illustrating a manufacturing example in the case where a groove portion is formed on one surface of a heat transfer suppression layer using an embossing roller and a flat roller. FIG. 7 is a diagram illustrating a manufacturing example in the case where a groove is formed in the heat transfer suppression layer by press working. FIG. 8 is a diagram illustrating a manufacturing example in the case where a groove is formed in the heat transfer suppression layer by end milling.

The present inventors have an assembled battery that can cool a battery cell during normal use in which heat at a relatively low temperature is generated while suppressing propagation of heat between the battery cells at an abnormal time in which high-temperature heat is generated. In order to provide heat transfer suppression sheets for automobiles, we have conducted intensive studies.

As a result, it has a heat transfer suppression layer containing inorganic particles and / or inorganic fibers, and the heat transfer suppression layer has a groove that communicates with the end surface in the in-plane direction of the heat transfer suppression layer, and the groove It has been found that the above-mentioned problems can be solved by interposing a heat transfer suppression sheet having a concavo-convex shape on the surface between battery cells.

That is, by having a heat transfer suppression layer containing inorganic particles and / or inorganic fibers, when thermal runaway occurs in a certain battery cell, it effectively suppresses the propagation of heat to other adjacent battery cells. Can do.

On the other hand, the heat transfer suppression layer has a groove portion that communicates with the end surface in the in-plane direction of the heat transfer suppression layer, and the batteries stacked by the space formed between the groove portion and the adjacent battery cell. Since the heat staying between the cells (that is, the heat staying in the heat transfer suppression layer) easily escapes outside, the battery cell during normal use can be cooled.

Furthermore, in the present invention, since the surface of the groove part has a concavo-convex shape, the surface area of the groove part increases as compared to the case where the surface of the groove part does not have a concavo-convex shape, so that the heat retained in the heat transfer suppression layer is further increased Easier to escape. As a result, the battery cell during normal use can be more effectively cooled as compared to a heat insulating sheet having a groove portion that does not have an uneven shape on the surface as shown in Patent Document 2.

In addition, in order to cool the battery cells during normal use, a space for releasing the generated heat to the outside is provided between the battery cells, and also for suppressing the propagation of heat between the battery cells at the time of abnormality. Since no space is provided between the battery cells, it is not necessary to make the distance between the battery cells extremely large. For this reason, it is also possible to reduce the thickness of the entire heat transfer suppressing sheet (for example, 5 mm or less). As a result, while ensuring the safety of the assembled battery and sufficient charge / discharge performance of the battery cell, It is also possible to improve the volume energy density.

Hereinafter, embodiments (present embodiments) of the present invention will be described in detail with reference to the drawings. In the following, “to” means not less than the lower limit value and not more than the upper limit value.

(First embodiment)
First, the assembled battery heat transfer suppression sheet according to the first embodiment of the present invention will be described. The first embodiment is a case where the heat transfer suppression sheet is a single layer.

<Basic configuration of heat transfer suppression sheet>
FIG. 1 is a cross-sectional view schematically showing a configuration example of the assembled battery heat transfer suppression sheet 10 according to the first embodiment.
The heat transfer suppression sheet 10 according to the present embodiment has a heat transfer suppression layer 20 containing inorganic particles and / or inorganic fibers. In addition, the heat transfer suppression layer 20 includes a groove portion 22 that communicates with

end surfaces

26 and 28 in the in-plane direction of the heat transfer suppression layer 20. In the present embodiment, the groove 22 has a plurality of grooves formed in a lattice shape as shown in FIG.
Furthermore, as shown in the enlarged view of the groove portion 22 in FIG. 1, the surface of the groove portion 22 has a fine uneven shape 24.

Since the heat transfer suppressing layer 20 constituting the heat transfer suppressing sheet 10 contains at least one of inorganic particles and inorganic fibers, it plays a role of an endothermic layer or a heat insulating layer as will be described later. And in the assembled battery 100 comprised by the some battery cell 50 laminated | stacked, when the thermal runaway arises in a certain battery cell 50 by arrange | positioning the heat transfer suppression sheet | seat 10 between the battery cells 50, it adjoins. The propagation of heat to other battery cells 50 can be effectively suppressed.

Further, since the heat transfer suppression layer 20 has the groove portion 22 that communicates with the end surfaces 26 and 28 in the in-plane direction of the heat transfer suppression layer 20, the heat transfer suppression layer 20 is laminated by a space formed between the groove portion 22 and the adjacent battery cell 50. Since the heat staying between the battery cells 50 (that is, the heat staying in the heat transfer suppressing layer) easily escapes outside, the battery cells 50 can be cooled during normal use.

In addition, it is preferable that the groove part 22 connects the one end surface 26 and the other end surface 28. Since the groove portion 22 communicates with the at least two

end surfaces

26 and 28, both the one end and the other end of the groove portion 22 face the end surfaces 26 and 28, so that the heat staying in the heat transfer suppression layer 20 is outside. Easier to escape. However, if at least one end of the groove portion 22 faces the end surfaces 26 and 28, heat can be released to the outside. Therefore, it is only necessary that at least one end of the groove portion 22 communicates with the end surfaces 26 and 28.

Moreover, as shown in FIG. 1, the heat transfer suppression layer 20 has a quadrangular outer shape in plan view, and the groove 22 communicates two adjacent end surfaces 26 and 28 among the four end surfaces. Is preferred. By having the above configuration, the heat staying in the heat transfer suppression layer 20 can escape in the direction perpendicular to the end face 26 and in the direction perpendicular to the end face 28, compared with the case where heat is released only in one direction. , Can escape the heat more effectively.
Note that the quadrangle that is the outer shape can include various quadrangles such as a square, a rectangle, and a trapezoid. The corners of the quadrangle may have an R shape.

Furthermore, in this embodiment, since the surface of the groove part 22 has the concavo-convex shape 24, the surface area of the groove part 22 is increased as compared with the case where the surface of the groove part 22 does not have the concavo-convex shape 24. The heat staying inside becomes easier to escape to the outside. For this reason, compared with the heat insulation sheet in which the groove part 22 which does not have the uneven | corrugated shape 24 was formed on the surface, the battery cell 50 at the time of normal use can be cooled more effectively.

Then, the uneven | corrugated shape 24 which has on the surface of the groove part 22 is demonstrated in detail. FIG. 2 is an enlarged view of the uneven shape 24 of the groove 22 in FIG. As shown in FIG. 2, the surface of the groove portion 22 has the concavo-convex shape 24 because the heat transfer suppression layer 20 is composed of a large number of inorganic particles (or inorganic fibers) 30 and the surface of the heat transfer suppression layer 20 is concavo-convex. This is caused by forming 24.

As will be described later, the heat transfer suppression layer 20 formed of a large number of inorganic particles 30 of several μm level has a surface with a pitch and depth of several μm compared to a heat insulating sheet made of a resin such as polycarbonate or polypropylene. A large number of concave and convex shapes 24 having a thickness are provided. For this reason, when the groove part 22 is formed in the heat transfer suppression layer 20 by a predetermined groove forming means described later, a large number of inorganic particles 30 are also exposed on the surface of the groove part 22. As a result, the surface of the groove portion 22 has a fine uneven shape 24 composed of the inorganic particles 30.

Here, the lower limit of the pitch and depth of the unevenness is 0.5 μm, preferably 1.0 μm or more. The upper limit of the pitch and depth of the irregularities is 100 μm, preferably 80 μm or less, more preferably 60 μm or less, and further preferably 40 μm or less.
If the pitch or depth of the unevenness is less than 0.5 μm, voids generated in the heat transfer suppression layer 20 become too small and convection is less likely to occur, making it difficult to come into contact with heat. There is a possibility that the heat staying in 20 cannot be effectively released to the outside. On the other hand, if the pitch or depth of the unevenness exceeds 100 μm, the average particle size of the inorganic particles 30 is too large and the specific surface area of the inorganic particles 30 is reduced, so that the heat staying in the heat transfer suppression layer 20 is effective. There is a risk that you cannot escape outside.
In addition, the pitch of unevenness means the distance between centers of adjacent recessed parts or convex parts, and the depth of unevenness means the distance between the bottom part of a recessed part and the top part of a convex part.

Incidentally, in FIG. 1, a lattice-like shape is shown as the shape of the groove portion 22 when the heat transfer suppressing layer 20 is viewed in plan, but the shape of the groove portion 22 is not limited to this. For example, as shown in FIG. 3A, a grid-like groove 22 having corners R processed, a groove 22 having a labyrinth structure as shown in FIG. 3B, or a groove 22 having a flat circular emboss structure as shown in FIG. 3C. 3D, a honeycomb-shaped groove 22 as shown in FIG. 3D, a square-concave convex groove 22 as shown in FIG. 3E, a square-concave groove 22 as shown in FIG. 3F, or as shown in FIG. 3G It is possible to employ variously shaped groove portions 22 such as a corrugated groove portion 22.

Further, the number of the groove portions 22 is not particularly limited. However, as the number of the groove portions 22 increases, the effect of releasing heat from the battery cell 50 during normal use is enhanced, while the heat transfer suppressing layer 20 other than the groove portions 22 is increased. The proportion of the portion may decrease, and the function of suppressing heat transfer between the battery cells 50 may be reduced. Therefore, it is preferable to determine the number of grooves 22 in view of the balance between cooling during normal use and heat transfer suppression during abnormal conditions.

In addition, as a concrete usage form of this heat transfer suppression sheet | seat 10, as shown in FIG. 4, the some battery cell 50 is arrange | positioned through the heat transfer suppression sheet | seat 10, and several battery cells 50 are in series. Alternatively, the assembled battery 100 is configured by being stored in the battery case 60 in a state of being connected in parallel (the connected state is not shown). In addition, although the lithium ion secondary battery is used suitably, for example, the battery cell 50 is not specifically limited to this, It can apply also to another secondary battery.

<Details of heat transfer suppression sheet>
Next, each component in the assembled battery heat transfer suppression sheet 10 will be described in detail.
The heat transfer suppression layer 20 constituting the assembled battery heat transfer suppression sheet 10 contains inorganic particles and / or inorganic fibers. The inorganic particles and the inorganic fibers may contain only one of them or may contain both.

[When the heat transfer suppression layer serves as an endothermic layer]
The inorganic particles 30 are preferably made of a material that releases moisture by heating. The heat transfer suppression layer 20 can play a role as an endothermic layer by containing a material that releases moisture by heating. When the heat transfer suppression layer 20 serves as an endothermic layer, when the heat transfer suppression layer 20 is heated by heat generated in a certain battery cell 50 when the battery cell 50 is abnormal, the heat transfer suppression layer 20 is heated. Releases moisture while absorbing water. Due to this endothermic action, the amount of heat generated by the battery cell 50 can be reduced. Therefore, when a thermal runaway occurs in a certain battery cell 50, the propagation of heat to other adjacent battery cells 50 can be effectively suppressed.

In addition, when the heat transfer suppression layer 20 plays a role as an endothermic layer, the heat transfer suppression layer 20 has the groove portion 22 and the surface of the groove portion 22 has the concavo-convex shape 24, thereby Since a large area capable of releasing moisture from the endothermic layer 44 during heat absorption can be ensured, the function as the endothermic layer 44 can be further exhibited, that is, the reaction rate of the endothermic reaction can be improved.
That is, in addition to the improvement of the cooling effect of the battery cell 50 during normal use as described above, the effect of suppressing heat transfer between the battery cells 50 at the time of abnormality can also be improved.

Here, if the pitch or depth of the unevenness is less than 0.5 μm, voids generated in the heat transfer suppression layer 20 become too small, and convection is difficult to occur. The reaction rate of the reaction may decrease. On the other hand, if the pitch or depth of the unevenness exceeds 100 μm, the average particle size of the inorganic particles 30 is too large and the specific surface area of the inorganic particles 30 is decreased, so that the reaction rate of the endothermic reaction may be decreased.

A specific material for obtaining the above effect is preferably an inorganic hydrate capable of releasing moisture at a relatively high temperature, and more specifically, an inorganic material having a thermal decomposition start temperature of 200 ° C. or higher. A hydrate is preferred. Since the temperature range of the battery cell at the time of abnormality is generally 200 ° C. or higher, by using an inorganic hydrate having a thermal decomposition starting temperature of 200 ° C. or higher, moisture is effectively released at the time of abnormality and heat is released. Can be absorbed.

Examples of the inorganic hydrate include aluminum hydroxide (Al (OH) ₃ ), magnesium hydroxide (Mg (OH) ₂ ), calcium hydroxide (Ca (OH) ₂ ), and zinc hydroxide (Zn (OH)). ₂ ), iron hydroxide (Fe (OH) ₂ ), manganese hydroxide (Mn (OH) ₂ ), zirconium hydroxide (Zr (OH) ₂ ), gallium hydroxide (Ga (OH) ₃ ) and the like. .
These inorganic hydrates may be used alone or in combination of two or more.

The thermal decomposition start temperature of aluminum hydroxide is about 200 ° C., the thermal decomposition start temperature of magnesium hydroxide is about 330 ° C., the thermal decomposition start temperature of calcium hydroxide is about 580 ° C., and zinc hydroxide The thermal decomposition start temperature of iron hydroxide is about 200 ° C., the thermal decomposition start temperature of iron hydroxide is about 350 ° C., the thermal decomposition start temperature of manganese hydroxide is about 300 ° C., and the thermal decomposition start temperature of zirconium hydroxide. Is about 300 ° C., and the thermal decomposition start temperature of gallium hydroxide is about 300 ° C.
If two or more kinds of inorganic hydrates having different pyrolysis start temperatures are used in combination, the battery cell 50 whose temperature has risen can be cooled in a wide temperature range, and the heat between the battery cells 50 during thermal runaway can be reduced. Propagation can be effectively suppressed, which is preferable.

For example, in the case of aluminum hydroxide, the aluminum hydroxide has about 35% water of crystallization. As shown in the following formula, the water of crystallization is released at the time of thermal decomposition, thereby providing a flame extinguishing function (endothermic reaction). It can be demonstrated.
2Al (OH) ₃ → Al ₂ O ₃ + 3H ₂ O
With this function, high-temperature heat generated in the battery cell 50 can be absorbed, and the amount of heat generated by the battery cell 50 can be reduced.

For example, an inorganic hydrate having a thermal decomposition temperature of 200 ° C. or higher, such as aluminum hydroxide, has a large overlap in temperature and temperature range on the surface of the battery cell 50 when a thermal runaway of the battery cell 50 occurs. Yes. For this reason, with the temperature rise of the battery cell 50 at the time of abnormality, a dehydration reaction (endothermic reaction) is generated by thermal decomposition, so that propagation of heat between the battery cells 50 can be effectively suppressed.

In particular, in the case of aluminum hydroxide, since the thermal decomposition start temperature is lower (thermal decomposition start temperature: about 200 ° C.) among the inorganic hydrates, the initial stage at the time of abnormality (relatively lower temperature) Therefore, it is preferable because the battery cell 50 can be cooled.

As the blending amount of the inorganic hydrate, a preferable upper limit is 90% by mass and a more preferable upper limit is 65% by mass with respect to the total mass of the materials constituting the heat transfer suppression layer 20. When this compounding quantity exceeds 90 mass%, there exists a possibility that sufficient intensity | strength as the heat transfer suppression sheet | seat 10 cannot be maintained.

It is also preferable to use a dehydrating agent that can be dehydrated at a temperature of 150 ° C. or lower as a material that releases moisture by heating.
By having a dehydrating agent that can be dehydrated in a temperature range from normal temperature (about 20 ° C.) to a maximum of about 150 ° C., which is the temperature range of the battery cell 50 during normal use, the temperature of the battery cell 50 is compared during normal use. When the temperature rises at a low temperature, the dehydrating agent releases moisture, so that the battery cell 50 can be effectively cooled during normal use.

Specific materials for obtaining the above-mentioned effects include, for example, a water adsorbent such as silica gel, activated alumina, activated carbon, zeolite, ion exchange resin, or sulfate hydrate, sulfite hydrate, phosphate water. Examples thereof include hydrates, nitrate hydrates, acetate hydrates, metal hydrates, and the like. These dehydrating agents may be used alone or in combination of two or more.

Here, as the sulfate hydrate, for example, ammonium aluminum sulfate 12 hydrate, sodium aluminum sulfate 12 hydrate, aluminum sulfate 27 hydrate, aluminum sulfate 18 hydrate, aluminum sulfate 16 hydrate, aluminum sulfate Decahydrate, aluminum sulfate hexahydrate, potassium aluminum sulfate 12 hydrate, iron sulfate heptahydrate, iron sulfate 9 hydrate, potassium iron sulfate 12 hydrate, magnesium sulfate heptahydrate, sulfuric acid Examples thereof include sodium decahydrate, nickel sulfate hexahydrate, zinc sulfate heptahydrate, beryllium sulfate tetrahydrate, zirconium sulfate tetrahydrate.
Examples of the sulfite hydrate include zinc sulfite dihydrate and sodium sulfite heptahydrate.
Examples of phosphate hydrates include aluminum phosphate dihydrate, cobalt phosphate octahydrate, magnesium phosphate octahydrate, magnesium ammonium phosphate hexahydrate, and magnesium hydrogen phosphate trihydrate. Products, magnesium hydrogen phosphate heptahydrate, zinc phosphate tetrahydrate, zinc dihydrogen phosphate dihydrate, and the like.

Examples of nitrate hydrates include aluminum nitrate nonahydrate, zinc nitrate hexahydrate, calcium nitrate tetrahydrate, cobalt nitrate hexahydrate, bismuth nitrate pentahydrate, zirconium nitrate pentahydrate. Cerium nitrate hexahydrate, iron nitrate hexahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate, magnesium nitrate hexahydrate and the like.
Examples of acetate hydrates include zinc acetate dihydrate and cobalt acetate tetrahydrate.
Examples of metal hydrate salts include chloride salts such as cobalt chloride hexahydrate and iron chloride tetrahydrate, borax (sodium tetraborate pentahydrate, sodium tetraborate decahydrate), Examples thereof include borates such as disodium octaborate tetrahydrate and zinc borate 3.5 hydrate.

For example, when a zeolite having a large moisture adsorption amount on the high temperature side (75 ° C. to 150 ° C.) within a temperature range of 150 ° C. or lower and silica gel having a small moisture adsorption amount on the high temperature side are used in combination, the temperature rises. It is preferable because the battery cell 50 can be cooled in a wide temperature range.

Among the dehydrating agents, it is particularly preferable to use zeolite from the viewpoint of being able to release more water and having a wide dehydrating temperature range. The zeolite is not particularly limited, and examples thereof include β-type zeolite, Y-type zeolite, ferrierite, ZSM-5-type zeolite, mordenite, forgesite, zeolite A, and zeolite L.

Zeolite is an aluminosilicate having a three-dimensional network structure. Since zeolite that adsorbs moisture is stably present, moisture and the like are usually adsorbed in the gaps of the three-dimensional network structure under normal temperature conditions. However, when heat above a certain temperature is applied, the moisture adsorbed on the zeolite is desorbed from the zeolite.
However, since the zeolite that does not adsorb moisture is unstable, the dehydrated zeolite has a high adsorption action, and therefore adsorbs moisture again after the temperature decreases.

For example, a dehydrating agent that can be dehydrated at a temperature of 150 ° C. or less, such as zeolite, greatly overlaps the temperature rise and temperature range of the surface of the battery cell 50 when performing a charge / discharge cycle. As the temperature rises by 50, the battery cell 50 can be effectively cooled by releasing moisture.

In particular, in the case of zeolite, after the battery cell 50 is cooled and the temperature of the dehydrating agent in the heat transfer suppressing layer 20 is lowered, moisture around the heat transfer suppressing layer 20 is adsorbed again. It can be reused any number of times for repeated charge / discharge cycles.

As a compounding quantity of a dehydrating agent, a preferable upper limit is 90 mass% with respect to the total mass of the material which comprises the heat transfer suppression layer 20, and a more preferable upper limit is 65 mass%.
On the other hand, the preferable minimum of the compounding quantity of a dehydrating agent is 10 mass%, and a more preferable minimum is 35 mass%. If the amount is less than 10% by mass, sufficient dehydration effect may not be obtained. Moreover, when this compounding quantity exceeds 90 mass%, there exists a possibility that sufficient intensity | strength as the heat transfer suppression sheet | seat 10 cannot be maintained.

The inorganic hydrate having a thermal decomposition starting temperature of 200 ° C. or higher and the dehydrating agent that can be dehydrated at a temperature of 150 ° C. or lower as described above may be used alone, but these may be used in combination. preferable. By using these together, the groove portion 22 having the concavo-convex shape 24 on the surface thereof is formed in the heat transfer suppression layer 20 to further exhibit the effect of achieving both heat transfer suppression during an abnormality and cooling during normal use. Can do. That is, in addition to coexistence of the above problems from the structural surface in the heat transfer suppression layer 20 having the groove portion 22, coexistence of the above problems from the material surface by using a material that exhibits endothermic action at the time of abnormality and normal use in combination. Can also be achieved.

In addition, the heat transfer suppression layer 20 may contain inorganic fibers or pulp fibers for the purpose of improving the strength at the time of molding.

Examples of the inorganic fiber include silica-alumina fiber, alumina fiber, silica fiber, rock wool, alkaline earth silicate fiber, glass fiber, zirconia fiber, and potassium titanate whisker fiber. These inorganic fibers are preferable in terms of heat resistance, strength, availability, and the like. An inorganic fiber may be used independently and may be used in combination of 2 or more types. Of the inorganic fibers, silica-alumina fiber, alumina fiber, silica fiber, rock wool, alkali earth silicate fiber, and glass fiber are particularly preferable from the viewpoint of handleability.

The cross-sectional shape of the inorganic fiber is not particularly limited, and examples thereof include a circular cross section, a flat cross section, a hollow cross section, a polygonal cross section, and a core-sheath cross section. Among these, a modified cross-section fiber having a hollow cross section, a flat cross section or a polygonal cross section can be preferably used because the heat insulation is slightly improved.

The preferable lower limit of the average fiber length of the inorganic fibers is 0.1 mm, and the more preferable lower limit is 0.5 mm. On the other hand, the preferable upper limit of the average fiber length of the inorganic fibers is 50 mm, and the more preferable upper limit is 10 mm. If the average fiber length of the inorganic fibers is less than 0.1 mm, the entanglement between the inorganic fibers is difficult to occur, and the mechanical strength of the obtained heat transfer suppression sheet 10 may be reduced. On the other hand, when the thickness exceeds 50 mm, although the reinforcing effect is obtained, the inorganic fibers cannot be intertwined closely or rounded with only a single inorganic fiber. There is a risk of lowering.

The preferable lower limit of the average fiber diameter of the inorganic fibers is 1 μm, the more preferable lower limit is 2 μm, and the still more preferable lower limit is 3 μm. On the other hand, the preferable upper limit of the average fiber diameter of the inorganic fibers is 10 μm, and the more preferable upper limit is 7 μm. There exists a possibility that the mechanical strength of inorganic fiber itself may fall that the average fiber diameter of inorganic fiber is less than 1 micrometer. In view of the influence on human health, the average fiber diameter of the inorganic fibers is preferably 3 μm or more. On the other hand, if the average fiber diameter of the inorganic fibers is larger than 10 μm, solid heat transfer using the inorganic fibers as a medium may increase, leading to a decrease in heat insulation, and the formability of the heat transfer suppressing sheet 10 may be deteriorated. There is a fear.

These inorganic fibers and pulp fibers can be used as necessary in the range of 10 to 70% by mass with respect to the total weight of the materials constituting the heat transfer suppressing layer 20.

An organic binder may be used as necessary as a material constituting the heat transfer suppression layer 20. The organic binder is useful for the purpose of improving the strength at the time of molding, and for example, a polymer flocculant or an acrylic emulsion can be suitably used.
The organic binder can be used as necessary in the range of 0.5 to 5.0 mass% with respect to the total weight of the materials constituting the heat transfer suppressing layer 20.

The thickness of the heat transfer suppression sheet 10 is not particularly limited, but is preferably in the range of 0.05 to 5 mm. If the thickness of the heat transfer suppression sheet 10 is less than 0.05 mm, sufficient mechanical strength cannot be imparted to the heat transfer suppression sheet 10. On the other hand, if the thickness of the heat transfer suppression sheet 10 exceeds 5 mm, it may be difficult to form the heat transfer suppression sheet 10 itself.

In addition, as a specific combination of the dehydrating agent and the inorganic hydrate used for the heat transfer suppressing layer 20, the moisture adsorption amount is high even at a relatively high temperature (about 100 ° C. to 150 ° C.) among the above dehydrating agents. A combination of zeolite and aluminum hydroxide having a lower thermal decomposition starting temperature (thermal decomposition starting temperature: about 200 ° C.) among the inorganic hydrates is preferable.
This is preferable because the battery cell 50 can be effectively cooled even in a boundary temperature range (about 150 ° C. to 200 ° C.) between the temperature range during normal use and the temperature range during abnormal operation.

[When the heat transfer suppression layer acts as a heat insulation layer]
When the heat transfer suppression layer 20 plays a role as a heat insulating layer, the heat transfer suppression layer 20 only needs to include at least one of inorganic particles and inorganic fibers. By including, the effect as a heat insulating material can be exhibited. However, the inclusion of both inorganic particles and inorganic fibers enables the inorganic particles to divide continuous voids in the structure formed by the entanglement of the inorganic fibers, so that the convective heat transfer in the heat transfer suppression layer 20 is effectively performed. It becomes possible to reduce, and the heat insulation effect can be exhibited more effectively.

Examples of the inorganic fiber include silica-alumina fiber, alumina fiber, silica fiber, rock wool, alkaline earth silicate fiber, glass fiber, zirconia fiber, and potassium titanate whisker fiber. These inorganic fibers are preferable in terms of heat resistance, strength, availability, and the like. The said inorganic fiber may be used independently and may be used in combination of 2 or more types. Of the inorganic fibers, silica-alumina fiber, alumina fiber, silica fiber, rock wool, alkali earth silicate fiber, and glass fiber are particularly preferable from the viewpoint of handleability.

Subsequently, examples of the inorganic particles include TiO ₂ powder, SiO ₂ powder, BaTiO ₃ powder, PbS powder, ZrO ₂ powder, SiC powder, NaF powder, and LiF powder. These inorganic particles may be used alone or in combination of two or more.

When the inorganic particles are used in combination, preferred combinations include a combination of TiO ₂ powder and SiO ₂ powder, a combination of TiO ₂ powder and BaTiO ₃ powder, a combination of SiO ₂ powder and BaTiO ₃ powder, or TiO combination of ₂ powder and SiO ₂ powder and BaTiO ₃ powder.

In addition, TiO ₂ powder has a high refractive index with respect to infrared rays, and has an effect of improving heat insulation in a high temperature range. In addition, since the SiO ₂ powder has a low solid thermal conductivity and is easy to form fine voids with fine particles, convection is suppressed and there is an effect of improving heat insulation in a low temperature region. Therefore, when TiO ₂ powder and SiO ₂ powder are used in combination, heat insulation in a wide temperature range from a low temperature range to a high temperature range can be expected, and these combinations are particularly preferable.

When both inorganic particles and inorganic fibers are included as the material constituting the heat transfer suppression layer 20, the preferred upper limit of the amount of inorganic fibers is 50 masses with respect to the total weight of the materials constituting the heat transfer suppression layer 20 %, And a more preferable upper limit is 40% by mass. On the other hand, a preferable lower limit of the blending amount of the inorganic fibers is 5% by mass, and a more preferable lower limit is 10% by mass. If the blending amount is less than 5% by mass, the reinforcing effect by the inorganic fibers cannot be obtained, the handleability and mechanical strength of the heat transfer suppression layer 20 may be lowered, and good moldability may not be obtained. There is. On the other hand, when the blending amount exceeds 50% by mass, there are many continuous voids in the structure in which the inorganic fibers constituting the heat transfer suppression layer 20 are intertwined, and convection heat transfer, molecular heat transfer, radiation heat transfer. Increases the heat insulation properties.

When both inorganic particles and inorganic fibers are included as a material constituting the heat transfer suppression layer 20, the preferred upper limit of the amount of inorganic particles is 95 mass with respect to the total weight of the materials constituting the heat transfer suppression layer 20. %, And a more preferable upper limit is 90% by mass. On the other hand, the preferable minimum of the compounding quantity of an inorganic particle is 50 mass%, and a more preferable minimum is 60 mass%. When the blending amount of the inorganic particles is within the above range, it is possible to obtain an effect of reducing convective heat transfer by dividing continuous voids in the entangled structure of the inorganic fibers while maintaining the reinforcing effect by the inorganic fibers.

The preferable lower limit of the average particle diameter of the inorganic particles is 0.5 μm, and the more preferable lower limit is 1 μm. On the other hand, the preferable upper limit of the average particle size of the inorganic particles is 20 μm, and the more preferable upper limit is 10 μm. If the average particle size of the inorganic particles is less than 0.5 μm, not only the heat transfer suppression layer 20 is difficult to manufacture, but also the radiation heat scattering becomes insufficient, and the thermal conductivity of the heat transfer suppression layer 20 increases (ie, , There is a risk that the heat insulation will be reduced). On the other hand, when the average particle size of the inorganic particles exceeds 20 μm, voids generated in the heat transfer suppression layer 20 become extremely large, and thus convection heat transfer and molecular heat transfer increase, and in this case also the heat conductivity increases. Resulting in.

The shape of the inorganic particles is not particularly limited as long as the average particle diameter is in the above range, and examples thereof include spheres, ellipsoids, polyhedrons, shapes having irregularities and protrusions on the surface, and irregular shapes. Can be mentioned.

Further, in the inorganic particles, the ratio of the refractive index to light having a wavelength of 1 μm or more (specific refractive index) is preferably 1.25 or more. The inorganic particles have a very important role as a radiant heat scattering material, and the larger the refractive index, the more effectively the radiant heat can be scattered. The relative refractive index is extremely important for the suppression of phonon conduction, and the larger the value, the better the suppression effect.

As a material capable of suppressing phonon conduction, a substance having a lattice defect in a crystal or a substance having a complicated structure is generally known. Since TiO ₂ , SiO ₂ , and BaTiO ₃ described above are likely to have lattice defects and have a complicated structure, it is considered effective not only for radiant heat scattering but also for phonon scattering.

Furthermore, inorganic particles having a reflectance of 70% or more for light having a wavelength of 10 μm or more can be suitably used as the inorganic particles. The light with a wavelength of 10 μm or more is light in the so-called infrared to far-infrared wavelength region, and the reflectance for light in this wavelength region is 70% or more, so that radiant heat transfer can be reduced more effectively.

The solid particles preferably have a solid thermal conductivity of 20 W / m · K or less at room temperature. When inorganic particles having a solid thermal conductivity greater than 20 W / m · K at room temperature are used as raw materials, the solid heat transfer becomes dominant in the heat transfer suppression layer 20 and the thermal conductivity is increased (decreasing heat insulation). There is a risk of it.

In the present embodiment, the inorganic fiber refers to an inorganic material having an aspect ratio of 3 or more. On the other hand, the inorganic particles refer to inorganic materials having an aspect ratio of less than 3. The aspect ratio means the ratio (b / a) of the major axis b to the minor axis a of the substance.

The heat transfer suppression layer 20 may contain an inorganic binder for the purpose of maintaining strength at high temperatures. Examples of the inorganic binder include colloidal silica, synthetic mica, and montmorillonite. An inorganic binder may be used independently and may be used in combination of 2 or more types.

This inorganic binder can be used as necessary in the range of 1 to 10% by mass with respect to the total weight of the constituent materials of the heat transfer suppressing layer 20. As a usage mode of the inorganic binder, for example, it can be used by mixing in a raw material or impregnating the obtained heat insulating material.

Furthermore, an organic elastic substance may be used as a constituent material of the heat transfer suppression layer 20 as necessary. This organic elastic material is useful in the case where the heat transfer suppressing layer 20 is made flexible. For example, natural rubber emulsion, synthetic rubber latex binder such as acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), etc. It can be preferably used. In particular, when the heat transfer suppressing layer 20 of the present embodiment is manufactured by a wet molding method, the flexibility can be improved by using the organic elastic material.

The blending amount of the organic elastic substance is preferably in the range of 0 to 5% by mass with respect to the total weight of the constituent materials of the heat transfer suppression layer 20. When the blending amount of the organic elastic material exceeds 5% by mass, the organic elastic material is burnt down when used in a high temperature range of 700 ° C. or more, and the voids are remarkably increased. is there.

The thickness of the heat transfer suppression layer 20 is not particularly limited, but is preferably in the range of 0.1 to 4.0 mm. If the thickness of the heat transfer suppression layer 20 is less than 0.1 mm, sufficient mechanical strength cannot be imparted to the heat transfer suppression layer 20. On the other hand, if the thickness of the heat transfer suppression layer 20 exceeds 4.0 mm, the volume energy density of the assembled battery may be reduced.

The inorganic particles constituting the heat transfer suppressing layer 20 do not easily escape to the outside of the heat transfer suppressing layer 20, but a part or all of the heat transfer suppressing layer 20 is necessary for the purpose of preventing the inorganic particles from escaping. May be densified. When the inorganic particles constituting the heat transfer suppression layer 20 are included in a structure in which inorganic fibers are entangled, they do not easily escape from between the inorganic fibers. However, depending on the usage environment, a strong impact or the like may be applied to the heat transfer suppression layer 20 and the inorganic particles may escape into the air. Therefore, the structure of the inorganic fibers in the portion including the inorganic particles is densified, The inorganic particles may be prevented from escaping.

Examples of a method for densifying the heat transfer suppression layer 20 include a method of heating so as to melt only the surface of the entangled structure of inorganic fibers, and a method of covering the surface of the heat transfer suppression layer 20 with a heat resistant film or the like. However, there is no particular limitation as long as the inorganic particles do not escape.

The bulk density of the heat transfer suppression layer 20 is not particularly limited, but is preferably in the range of 0.1 to 1.0 g / cm ³ . The bulk density can be obtained as a value obtained by dividing the mass by the apparent volume (see JIS A0202_2213). When the bulk density is less than 0.1 g / cm ³ , convective heat transfer and molecular heat transfer increase, while when the bulk density exceeds 1.0 g / cm ³ , the solid heat transfer increases and the thermal conductivity increases. In either case, the heat insulating properties are reduced.

(Second Embodiment)
Then, the heat transfer suppression sheet for assembled batteries which concerns on the 2nd Embodiment of this invention is demonstrated. 2nd Embodiment is a case where a heat transfer suppression sheet | seat is a multilayer (laminated body).

FIG. 5 is a diagram schematically showing a configuration example of the assembled battery heat transfer suppression sheet 10 according to the second embodiment of the present invention. In the heat transfer suppression sheet 10 according to the present embodiment, the heat transfer suppression layer 20 includes a heat insulating layer 42 having inorganic particles and / or inorganic fibers, and an endothermic material containing a material that releases moisture by heating. It is composed of layer 44.

According to this embodiment, the material (specifically, the above-mentioned inorganic hydrate or dehydrating agent) that releases moisture in the heat absorbing layer 44 that is the outer layer is heated by the heat generated in a certain battery cell 50. Then, the material releases moisture while absorbing the heat. Due to this endothermic effect, the amount of heat generated by the battery cell 50 can be effectively reduced. And the propagation of the heat between the battery cells 50 can be effectively suppressed by the heat insulation layer 42 which is an intermediate | middle layer for the reduced heat. For this reason, even if the amount of heat generated from the battery cell 50 is large, a sufficient heat insulating effect can be obtained. As a result, when a thermal runaway occurs in a certain battery cell 50, the propagation of heat to other adjacent battery cells 50 can be effectively suppressed, and the effect of causing a thermal runaway of other battery cells 50 is effective. Can be suppressed.

Further, in the present embodiment, as shown in FIG. 5, the groove portion 22 is provided in the heat absorption layer 44 which is the outer layer, and the surface of the groove portion 22 has an uneven shape 24 (not shown in FIG. 5). Therefore, the battery cell 50 can be cooled during normal use. Furthermore, as described above, since the endothermic layer 44 has the groove portion 22 having the concavo-convex shape 24 on the surface, it is possible to secure a large area from which moisture can be released from the endothermic layer 44 when the heat is absorbed. The function as the layer 44 can be further exhibited.

In addition, as a specific material used for the heat insulation layer 42 and the heat absorption layer 44 in this embodiment, the same material as that described in the first embodiment can be applied.

(Method of manufacturing heat transfer suppression sheet)
Then, the manufacturing method of the heat transfer suppression sheet | seat 10 is demonstrated in detail.

<Manufacture of heat transfer suppression layer>
The heat transfer suppression layer 20 constituting the heat transfer suppression sheet 10 is manufactured by molding a material composed of at least inorganic particles or inorganic fibers by a dry molding method or a wet molding method. Below, the manufacturing method in the case of obtaining the heat-transfer suppression layer 20 by each shaping | molding method is demonstrated.

[When manufacturing using dry molding]
First, in the dry molding method, inorganic particles and / or inorganic fibers and, if necessary, inorganic binders, pulp fibers, organic binders and the like are charged into a mixer such as a V-type mixer in a predetermined ratio. After thoroughly mixing the materials charged in the mixer, the mixture is charged into a predetermined mold and pressed to obtain the heat transfer suppressing layer 20. You may heat as needed at the time of a press.

The press pressure is preferably in the range of 0.98 to 9.80 MPa. If the press pressure is less than 0.98 MPa, the resulting heat transfer suppression layer 20 may not be able to maintain strength and may collapse. On the other hand, when the press pressure exceeds 9.80 MPa, workability may be reduced due to excessive compression, and further, the bulk density may be increased, so that solid heat transfer may increase and heat insulation may be deteriorated.

[When manufacturing using wet molding method]
Subsequently, in the wet molding method, inorganic particles and / or inorganic fibers, and if necessary, inorganic binders, pulp fibers, organic binders and the like are mixed and stirred in water to be sufficiently dispersed, and then a flocculant is added. Thus, primary aggregates are obtained. Next, if necessary, an emulsion of an organic elastic substance or the like is added to the water within a predetermined range, and then a polymer flocculant is added to obtain a slurry containing aggregates.

Next, a slurry containing the agglomerates is put into a predetermined mold to obtain a wet heat transfer suppressing layer 20. The intended heat transfer suppression layer 20 is obtained by drying the obtained heat transfer suppression layer 20.

As described above, the heat transfer suppressing layer 20 can be obtained by either a dry molding method or a wet molding method, but it is preferable to use a wet molding method in terms of ease of integral molding and mechanical strength.

In the case of the laminated heat transfer suppression layer 20 having the heat insulating layer 42 as an intermediate layer and the heat absorbing layers 44 on both sides thereof as shown in FIG. 5, the heat insulating layer 42 and the heat absorbing layer 44 are respectively described above. Then, the heat insulating layer 42 and the endothermic layer 44 can be manufactured by a pressure press in a wet state, a method of bonding using an adhesive after drying these members, or the like.

<Groove formation in heat transfer suppression layer>
A method for forming the groove 22 in the heat transfer suppression layer 20 obtained above will be described.
For example, as shown in FIG. 6A, the groove portions 22 are formed on both surfaces by sandwiching two embossed rollers 72 having a desired emboss shape from above and below and forming the groove portions 22 on both surfaces of the heat transfer suppression layer 20. The heat transfer suppressing sheet 10 can be obtained. Moreover, when obtaining the heat transfer suppression sheet | seat 10 which has the groove part 22 only in one side, as shown to FIG. 6B, the embossing roller 72 and the flat roller 74 can be used.

In addition, as shown in FIG. 7, the heat transfer in which the groove 22 is formed can also be performed by pressing the heat transfer suppressing layer 20 between the press working jig 82 having a desired shape and the pedestal 84. The suppression sheet 10 can be obtained.
Alternatively, as shown in FIG. 8, by forming a desired groove 22 on the surface of the heat transfer suppression layer 20 by processing using an end mill 90, the heat transfer suppression sheet 10 in which the groove 22 is formed can be obtained. it can.

In any of the above methods, since the heat transfer suppression layer 20 contains inorganic particles and / or inorganic fibers, the surface of the groove 22 has a fine uneven shape 24. The effects as described above can be obtained.

Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood. In addition, the constituent elements in the above-described embodiment may be arbitrarily combined without departing from the spirit of the invention.

This application is based on a Japanese patent application filed on May 22, 2018 (Japanese Patent Application No. 2018-097970), the contents of which are incorporated herein by reference.

10 Heat Transfer Suppression Sheet for Battery Assembly 20 Heat Transfer Suppression Layer 22 Groove 24 Uneven Shape 26 End Face (One End Face)
28 End faces (other end faces)
30 Inorganic particles (or inorganic fibers)
42 heat insulation layer 44 endothermic layer 50 battery cell 60 battery case 72 emboss roller 74 flat roller 82 press jig 84 pedestal 90 end mill 100 assembled battery

Claims

A plurality of battery cells are arranged via a heat transfer suppression sheet, the heat transfer suppression sheet used in an assembled battery in which the plurality of battery cells are connected in series or in parallel,
While having a heat transfer suppression layer containing inorganic particles and / or inorganic fibers,
The heat transfer suppression layer has a groove portion that communicates with the end surface in the in-plane direction of the heat transfer suppression layer,
The assembled battery heat transfer suppression sheet, wherein a surface of the groove has an uneven shape.
The said groove part is a heat-transfer suppression sheet | seat for assembled batteries of Claim 1 which connects the said one end surface and the said other end surface.
The heat transfer suppression layer has a quadrangular outer shape in plan view,
3. The assembled battery heat transfer suppression sheet according to claim 1, wherein the groove portion communicates two adjacent end surfaces of the four end surfaces.
The heat transfer suppression layer contains the inorganic particles as essential,
The assembled battery heat transfer suppression sheet according to any one of claims 1 to 3, wherein the inorganic particles are made of a material that releases moisture upon heating.
The assembled battery according to claim 4, wherein the material that releases moisture by heating is an inorganic hydrate having a thermal decomposition start temperature of 200 ° C or higher and / or a dehydrating agent that can be dehydrated at a temperature of 150 ° C or lower. Heat transfer suppression sheet.
The material that releases moisture contains the inorganic hydrate as an essential component,
The inorganic hydrate is at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc hydroxide, iron hydroxide, manganese hydroxide, zirconium hydroxide, and gallium hydroxide. Item 6. The heat transfer suppression sheet for assembled batteries according to Item 5.
The material that releases moisture contains the dehydrating agent as an essential component,
The dehydrating agent comprises silica gel, activated alumina, activated carbon, zeolite, ion exchange resin, sulfate hydrate, sulfite hydrate, phosphate hydrate, nitrate hydrate, acetate hydrate and metal hydrate. The heat transfer suppression sheet for an assembled battery according to claim 5, which is at least one member of the group.
The heat transfer suppression layer contains the inorganic fiber as an essential component,
The inorganic fiber according to any one of claims 1 to 7, wherein the inorganic fiber is at least one selected from the group consisting of silica-alumina fiber, alumina fiber, silica fiber, rock wool, alkaline earth silicate fiber, and glass fiber. Heat transfer suppression sheet for assembled batteries.
The heat transfer suppression layer contains the inorganic particles as essential,
The assembled battery heat transfer suppression sheet according to any one of claims 1 to 8, wherein the inorganic particles are at least one selected from the group consisting of TiO 2 and SiO 2 .
The heat transfer suppressing layer includes a heat insulating layer containing the inorganic particles and / or the inorganic fibers, and a heat absorbing layer formed on both surfaces of the heat insulating layer and containing a material that releases moisture by the heating. The heat transfer suppressing sheet for an assembled battery according to any one of 4 to 7.
An assembled battery in which the plurality of battery cells are arranged via the heat transfer suppressing sheet for assembled battery according to any one of claims 1 to 10, and the plurality of battery cells are connected in series or in parallel.