JP7203568B2 - Heat transfer suppression sheet for assembled battery, sheet structure, and assembled battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat transfer suppressing sheet, a sheet structure, and an assembled battery, which are 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.

2. Description of the Related Art In recent years, from the viewpoint of environmental protection, the development of electric vehicles or hybrid vehicles driven by electric motors has been vigorously advanced. Such an electric vehicle or hybrid vehicle is equipped with an assembled battery in which a plurality of battery cells are connected in series or in parallel to serve as a power source for an electric motor for driving.

Lithium-ion secondary batteries, which have higher capacity and higher output than lead-acid batteries or nickel-metal hydride batteries, are mainly used for these battery cells. When thermal runaway occurs in one battery cell (that is, in the event of an abnormality), heat may propagate to other adjacent battery cells, causing thermal runaway in the other battery cells.

As a technique for suppressing the propagation of thermal runaway as described above, for example, Patent Document 1 discloses a power storage device including one or more power storage elements, one of which is one of the one or more power storage elements. A first plate member and a second plate member are arranged laterally of the first power storage element, and the first plate member and the second plate member are arranged so that their surfaces face each other, and the first plate member and the second plate member are arranged to face each other. A low thermal conductivity layer (for example, an air layer), which is a layer of a material having a lower thermal conductivity than the first plate and the second plate, is formed between the two plate members, whereby the first storage element Radiant heat from or toward the first storage element is blocked by the two plate members, and heat transfer from one of these two plate members to the other is suppressed by the low thermal conductivity layer, so the storage device and other objects.

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

JP 2015-211013 A JP 2009-163932 A

On the other hand, when the battery cells assembled into a battery are subjected to charge-discharge cycles (that is, during normal use), in order to fully demonstrate the charge-discharge performance of the battery cells, the temperature of the battery cell surface must be kept below a predetermined value ( for example, 150° C. or lower).

However, in Patent Document 1, a heat insulating layer is simply provided between a plurality of battery cells in order to suppress heat propagation during thermal runaway. Therefore, the battery cells that generate heat during normal use cannot be effectively cooled. could not.
Further, in Patent Document 2, by forming unevenness on the surface of the heat insulating buffer member, it is possible to achieve heat insulation between battery cells, and at the time of stacking battery cells, it is possible to achieve a ventilation effect by means of the grooves. Since the heat insulating cushioning member is made of a sheet made of polycarbonate resin or polypropylene resin, if grooves are provided in this sheet, it cannot be said that it is sufficient to cool the battery cells that generate heat during normal use, as will be described later. rice field.
Furthermore, in Patent Documents 1 and 2, the rigidity of the sheet that facilitates assembly when forming an assembled battery, and the dimensional fluctuation (dimensional change) between adjacent battery cells due to thermal expansion of the battery cells are also addressed. No mention is made of possible seat flexibility.

The present invention has been made in view of such circumstances, and in constructing an assembled battery in which a plurality of battery cells are connected in series or in parallel, the present invention suppresses heat propagation between battery cells in the event of an abnormality. An assembled battery that can effectively cool battery cells during normal use, has rigidity that facilitates assembly when assembled into an assembled battery, and has flexibility that can cope with thermal expansion of the battery cells. An object of the present invention is to provide a heat transfer suppressing sheet, a sheet structure, and an assembled battery.

In order to achieve the above object, the gist of the heat transfer suppression sheet for an assembled battery 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 arranged in series or in parallel. A heat transfer suppressing sheet used in a connected assembled battery, wherein a flat sheet containing a heat absorbing material and/or a heat insulating material is formed on both sides of a corrugated sheet containing a heat absorbing material and/or a heat insulating material. There is something to be done.

In a preferred embodiment of the heat transfer suppressing sheet for an assembled battery, on one or both sides of the corrugated sheet, adjacent crests of waves are connected to each other by connecting portions having vertical walls extending from the bottom to the top of the waves. connected along the direction of travel.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the connecting portion is formed from the bottom to the top of the wave.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the connecting portion is formed from the bottom of the wave to the middle of the wave height.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the connecting portions are formed on both sides of the corrugated sheet from the bottom of the wave to the middle of the wave height.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the thickness of the flat sheet is greater than the thickness of the corrugated sheet.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, at least one of the corrugated sheet and the flat sheet has a plurality of through holes in the thickness direction of the sheet.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, at least one of the corrugated sheet and the flat sheet essentially contains the heat-absorbing material, and the heat-absorbing material is an inorganic hydrate and/or It is a dehydrating agent.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the endothermic material essentially contains the inorganic hydrate, and the inorganic hydrate has a thermal decomposition initiation temperature of 200° C. or higher.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the inorganic hydrates include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc hydroxide, iron hydroxide, manganese hydroxide, zirconium hydroxide and water. At least one of the group consisting of gallium oxide.

In a preferred embodiment of the heat transfer suppression sheet for assembled battery, the inorganic hydrate is aluminum hydroxide.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the endothermic material essentially contains the dehydrating agent, and the dehydrating agent is silica gel, activated alumina, activated carbon, zeolite, ion exchange resin, or sulfate hydrate. , sulfite hydrates, phosphate hydrates, nitrate hydrates, acetate hydrates and metal hydrates.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, at least one of the corrugated sheet and the flat sheet essentially contains the heat insulating material, and the heat insulating material comprises inorganic fibers and/or inorganic particles. is.

In a preferred embodiment of the heat transfer suppressing sheet for assembled battery, the heat insulating material essentially contains the inorganic fiber, and the inorganic fiber is silica-alumina fiber, alumina fiber, silica fiber, rock wool, or alkaline earth silicate. At least one of the group consisting of fibers and glass fibers.

In a preferred embodiment of the heat transfer suppression sheet for assembled battery, the heat insulating material essentially contains the inorganic particles, and the inorganic particles are at least one of TiO ₂ and SiO ₂ .

Moreover, the gist of a sheet structure according to an aspect of the present invention is that a plurality of the heat transfer suppressing sheets for assembled battery according to any one of the above are superimposed and integrated.

In a preferred embodiment of the sheet structure, the corrugations of the corrugated sheets adjacent to each other in the overlapping direction have opposite phases to each other.

In a preferred embodiment of the sheet structure, at least one of the plurality of assembled battery heat transfer suppressing sheets has a corrugated direction different from that of the other corrugated sheets.

Further, the gist of the assembled battery according to one aspect of the present invention is that the plurality of battery cells is the heat transfer suppressing sheet for assembled battery according to any one of the above and / or The plurality of battery cells are arranged via a sheet structure and connected in series or in parallel.

In a preferred embodiment of the assembled battery, at least one of the heat transfer suppressing sheet for the assembled battery or the sheet structure interposed between the plurality of battery cells has a corrugated sheet in a different direction. different from that of

In the assembled battery heat transfer suppressing sheet according to the present invention, when arranged between a plurality of battery cells, the corrugated sheet and the flat sheet are formed of a material containing a heat insulating material and a heat absorbing material, so that abnormal It is possible to suppress the heat transfer between the battery cells at times. In addition, since a plurality of tunnel-shaped spaces are formed between the corrugated sheet and the flat sheet in a direction perpendicular to the wave traveling direction, the battery cells can be effectively cooled during normal use. can.
Furthermore, the heat transfer suppressing sheet for assembled battery according to the present invention is obtained by integrating and reinforcing a corrugated sheet and a flat sheet, and by suppressing the crushing of waves in the corrugated sheet, the rigidity of the entire sheet is improved. can be easily assembled into an assembled battery. In addition, since the corrugated portion of the corrugated sheet increases flexibility, it is possible to effectively absorb dimensional fluctuations due to thermal expansion of the battery cells.

In addition, according to the sheet structure according to the present invention in which the heat transfer suppressing sheet for assembled battery is laminated, it is possible to easily adapt to changes in the specifications of the assembled battery, for example, the number and dimensions of the battery cells, and the assembled battery. Assembleability at the time is further improved. In addition, it is possible to improve the cooling performance of the individual battery cells in the assembled battery during normal use, and to more effectively suppress heat transfer between battery cells in the event of an abnormality.

FIG. 1 is a perspective view showing a heat transfer suppression sheet for an assembled battery according to an embodiment (this embodiment) of the present invention. FIG. 2 is an enlarged cross-sectional view of the main part of the heat transfer suppressing sheet for assembled battery shown in FIG. 1 along the traveling direction of waves. FIG. 3 is a perspective view of a heat transfer suppression sheet for an assembled battery according to a first modified example of this embodiment. FIG. 4 is a perspective view of a heat transfer suppression sheet for an assembled battery according to a second modification of the present embodiment. FIG. 5A is a perspective view of a heat transfer suppression sheet for an assembled battery according to a third modified example of this embodiment. FIG. 5B is a perspective view showing another example of the heat transfer suppressing sheet for assembled battery according to the third modification of the present embodiment. FIG. 6 is a perspective view of a heat transfer suppression sheet for an assembled battery according to a fourth modified example of this embodiment. FIG. 7 is a perspective view showing a sheet structure in which the heat transfer suppressing sheet for assembled battery according to the present embodiment is laminated in three layers. FIG. 8 is a perspective view of a sheet structure in which the corrugations of the corrugated sheets adjacent to each other in the overlapping direction have opposite phases. FIG. 9 is a cross-sectional view schematically showing the configuration of an assembled battery to which the heat transfer suppressing sheet for assembled battery according to this embodiment is applied. FIG. 10 is a perspective view showing the assembled battery shown in FIG. 9 with the battery case removed. FIG. 11 is a perspective view corresponding to FIG. 10 when the corrugated sheets have different corrugated directions between a plurality of assembled battery heat transfer suppressing sheets. 12A and 12B are schematic diagrams showing one manufacturing method of the heat transfer suppressing sheet for the assembled battery of FIG.

The inventors of the present invention can cool battery cells during normal use when relatively low-temperature heat is generated, while suppressing heat transfer between battery cells in an abnormal state when high-temperature heat is generated. Intensive studies have been made to provide a heat transfer suppressing sheet for an assembled battery that facilitates assembly when forming an assembled battery and that can cope with thermal expansion of battery cells.

As a result, by using a heat transfer suppressing sheet for an assembled battery in which a flat sheet containing a heat absorbing material and/or a heat insulating material is formed on both sides of a corrugated sheet containing a heat absorbing material and/or a heat insulating material , found that the above problems can be solved.

That is, the heat transfer suppressing sheet for an assembled battery according to the present invention is obtained by integrating and reinforcing a corrugated sheet and a flat sheet. can increase the It is possible to improve the assemblability of the battery cells when assembling the assembled battery.

In addition, due to the flexibility of the corrugated sheet in the wave height direction, it is possible to effectively absorb dimensional fluctuations due to thermal expansion of the battery cells during normal use and variations in the gaps between battery cells when forming a battery. .

Furthermore, the heat-absorbing material and/or heat-insulating material constituting the corrugated sheet and the flat sheet effectively prevent the heat caused by thermal runaway in a certain battery cell from being propagated to other adjacent battery cells in the event of an abnormality. can be suppressed to

In addition, a plurality (preferably, a large number) of tunnel-shaped spaces are formed between the corrugated sheet and the flat sheet in a direction perpendicular to the direction of propagation of the waves. Since the heat from the battery cells is easily released to the outside, the cooling performance of the battery cells during normal use is enhanced.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the heat transfer suppressing sheet for assembled battery is abbreviated as "heat transfer suppressing sheet".

<1. Configuration of Heat Transfer Suppressing Sheet>
[1-1. Basic configuration]
FIG. 1 is a perspective view of a heat transfer suppression sheet 10 according to this embodiment.
The heat transfer suppressing sheet 10 according to the present embodiment includes a flat sheet 20 containing a heat absorbing material and/or a heat insulating material and a corrugated sheet 30 containing a heat absorbing material and/or a heat insulating material. Flat sheets 20 are formed on both sides of the flat sheet 30 . That is, the corrugated sheet 30 is sandwiched between the pair of flat sheets 20, 20 and integrated. As a result, between the flat sheets 20, 20 and the corrugated sheet 30, there is a tunnel-like space extending in a direction perpendicular to the advancing direction of the waves 31 of the corrugated sheet 30 (that is, the horizontal direction of the paper surface). 36 are formed. Both end surfaces 26, 26 of the corrugated sheet 30 in the direction perpendicular to the traveling direction of the wave 31 are open, and the space 36 communicates with the outside air.

Here, since the flat sheet 20 contains a heat-absorbing material and/or a heat-insulating material, it absorbs and/or insulates the heat from the battery cell 50 that has undergone thermal runaway in the event of an abnormality. Propagation to the battery cell 50 is suppressed.
In addition, in the assembled battery 100, the flat sheet 20 is in surface contact with the battery cell 50, so that the flat sheet 20 can efficiently receive a large amount of heat from the battery cell 50 in which thermal runaway has occurred. Therefore, the effect of suppressing heat propagation between battery cells can be sufficiently exhibited.

Even if the heat that is not absorbed and/or insulated by the flat sheet 20 is radiated through the flat sheet 20, the corrugated sheet 30 also has the same heat absorption and/or heat insulation performance as the flat sheet 20. Therefore, the corrugated sheet 30 absorbs and/or insulates heat.

Furthermore, the heat from the flat sheet 20 can be released to the outside air through the tunnel-shaped space 36 formed between the flat sheet 20 and the corrugated sheet 30 . That is, the heat transfer suppressing sheet 10 of the present embodiment suppresses heat transfer from the battery cells 50 in an abnormal state in a triple manner by the two flat sheet 20 and the corrugated sheet 30, and suppresses the heat transfer to the outside air. can escape effectively.

In addition, since heat from the battery cells can easily escape through the tunnel-shaped space 36, the cooling performance of the battery cells during normal use is enhanced.

Further, the heat transfer suppressing sheet 10 according to the present embodiment is obtained by integrating and reinforcing the corrugated sheet 30 and the flat sheet 20, and by suppressing the crushing of the waves 31 in the corrugated sheet 30, the sheet It can increase the overall rigidity. The handleability is improved. As a result, it is possible to improve the ease of assembly of the battery cells 50 when assembling the assembled battery 100 .

Furthermore, the corrugated sheet 30 has increased flexibility due to the corrugated portion, and the corrugated sheet 30 is easily deformed in the wave height direction, so that dimensional fluctuation due to thermal expansion of the battery cells 50 can be effectively absorbed. .

The surface of the flat sheet 20 or the corrugated sheet 30 preferably has fine irregularities in order to improve the cooling performance and the heat transfer suppression performance. The minute unevenness increases the area of contact between the heat from the battery cells 50 and the air in the space 36, making it easier for the heat from the battery cells 50 to escape to the outside air. As a result, the battery cells 50 can be cooled more effectively during normal use, as compared to the heat insulating sheet having grooves formed on the surface without unevenness, as disclosed in Patent Document 2 above.

FIG. 2 is a cross-sectional view showing a part of the heat transfer suppressing sheet 10 in an enlarged manner along the traveling direction of the wave 31. As shown in FIG. Having the uneven shapes 22 and 32 on the surface of the flat sheet 20 or the corrugated sheet 30 means that the inorganic particles, inorganic fibers, etc. contained in the heat transfer suppressing sheet 10 (inorganic hydration as an endothermic material, which will be described below) (including inorganic particles and inorganic fibers as substances, dehydrating agents, and heat insulating materials) are bonded while maintaining their shape to form a sheet. As will be described later, the heat transfer suppressing sheet 10 formed of a large number of solid materials 34 on the level of several μm differs from a heat insulating sheet made of a resin such as polycarbonate or polypropylene, and its surface has a pitch and depth of several μm. It has a large number of uneven shapes 22 and 32 having a depth.

Here, the lower limits of the pitch and depth of the unevenness are each 0.5 μm, preferably 1.0 μm or more. The upper limits of the pitch and depth of the unevenness are each 100 μm, preferably 80 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less.

If the pitch or depth of the unevenness is less than 0.5 μm, the voids generated in the heat transfer suppressing sheet 10 become too small, making it difficult for convection to occur, making it difficult for heat to come into contact. There is a risk that it will not be possible to escape to the outside. On the other hand, if the pitch or depth of the unevenness exceeds 100 μm, the average particle size of the solid material 34 is too large, and the specific surface area of the solid material 34 decreases, so that heat may not be released effectively. be.
The pitch of the unevenness means the distance between the centers of adjacent recesses or between adjacent protrusions, and the depth of the unevenness means the distance between the bottom of the recess and the top of the protrusion.

[1-2. First modification]
FIG. 3 is a perspective view of a heat transfer suppression sheet 10 according to a first modified example of this embodiment. The heat transfer suppressing sheet 10 of this modification includes a flat sheet 20 containing an endothermic material and/or a heat insulating material and a corrugated sheet containing an endothermic material and/or a heat insulating material, as in the basic configuration described above. The flat sheet 20 and the corrugated sheet 30 are integrally formed.

However, the heat transfer suppressing sheet 10 of this modified example is different in that the plate thickness tp of the flat sheet 20 is thicker than the plate thickness tw of the corrugated sheet 30 . By increasing the plate thickness tp of the flat sheet 20, the endothermic performance and/or the heat insulating performance of the flat sheet 20 are enhanced, and the rigidity of the entire sheet is further improved.
Other configurations and effects are the same as those described in the basic configuration above.

[1-3. Second modification, third modification]
FIG. 4 is a perspective view of a heat transfer suppression sheet 10 according to a second modification of this embodiment, and FIG. 5A is a perspective view of a heat transfer suppression sheet 10 according to a third modification of this embodiment. In FIGS. 4 and 5A, the flat sheets 20 are originally formed on both sides of the corrugated sheet 30 (in the vertical direction of the paper surface). is omitted.
As shown in FIG. 4, the heat transfer suppressing sheet 10 has adjacent corrugations on one side surface 30a (“upper surface side” in FIG. 4) of a corrugated sheet 30 containing an endothermic material and/or a heat insulating material. The crests 31a and 31b of 31 are connected to each other by a connecting portion 35 in the traveling direction of the wave 31, that is, in the lateral direction of the paper surface. The connecting portions 35 act like ribs to suppress the crushing of the waves 31 of the heat transfer suppressing sheet 10 and increase the rigidity of the entire sheet. As a result, the ease of assembly when assembling the assembled battery 100 (see FIG. 9) is further improved.

In FIG. 4 , the connecting portion 35 is formed in a striped shape along the traveling direction of the waves 31 at approximately the center of the length of the corrugated sheet 30 in the direction parallel to the waves 31 (indicated by “width W” in the figure). Although one line is formed in each line, a plurality of lines may be formed at intervals.

The connecting portion 35 has a standing wall extending from the bottom 38 to the top 39 of the wave 31 and is formed along the traveling direction of the wave 31 . 4, the connecting portion 35 may be formed to reach from the bottom 38 to the top 39 of the wave 31, that is, to reach from the bottom 38 to the top 39 of the wave 31 (second modification example). Also, as shown in FIG. 5A, the wave 31 is formed from the bottom 38 to the middle of the wave height, that is, from the bottom 38 of the wave 31 to an arbitrary position of the wave height (for example, in FIG. 5A, the position is approximately the center of the wave height). (third modification). The connecting portion 35 functions as a reinforcing member for the waves 31 as described above, but as shown in FIG. Since the space 37 parallel to the width W is divided halfway in the direction perpendicular to the traveling direction of the wave at the position where the connecting part 35 is formed, the cooling of the battery cell 50 is improved compared to the case where the connecting part 35 is not provided. Performance may be degraded.

On the other hand, as shown in FIG. 5A , when the connecting portion 35 is formed halfway up the wave height, a space portion is formed between the battery cell 50 and the upper portion of the connecting portion 35 , so that a tunnel-like structure is formed. The space 37 is not divided halfway in the traveling direction of the wave at the position where the connecting portion 35 is formed. For this reason, compared with the case where the connection part 35 is formed up to the top part 39 as shown in FIG. Note that the distribution of the reinforcing effect and the cooling performance can be adjusted by adjusting the height of the connecting portion 35 from the bottom 38. Considering the balance between the two, the height of the connecting portion 35 from the bottom 38 is half the wave height. (central position) is preferred.

A single tunnel-shaped space 36 extending over the entire length of the width W of the wave 31 is formed on the surface 30b of the corrugated sheet 30 on which the connecting portion 35 is not formed (the "lower surface side" in the figure). Therefore, the cooling performance of the battery cells 50 in contact with the surface 30b of the corrugated sheet 30 on which the connecting portions 35 are not formed remains high in both the cases shown in FIGS. 5A and 6.

4, the connecting portion 35 is formed only on one side surface 30a of the corrugated sheet 30, but the connecting portion 35 may be formed only on the other side surface 30b. However, it may be formed on both the surface 30a on one side and the surface 30b on the other side.
Furthermore, the connecting portion 35 may be one that connects all of the crests 31a and 31b of the adjacent waves 31 as shown in FIG. In view of the balance, the peaks 31a and 31b of the adjacent waves 31 may be partially connected to each other.

Note that FIG. 5A shows that the connecting portion 35 is formed only on one side surface 30a of the corrugated sheet 30 from the bottom 38 of the wave 31 to the middle of the wave height, but FIG. As shown, it is preferable that connecting portions 35 are formed on both surfaces 30a and 30b of the corrugated sheet 30 from the bottom portion 38 of the wave 31 to the middle of the wave height. By forming the connecting portions 35 on both surfaces 30a and 30b of the corrugated sheet 30, the reinforcing effect is further improved. , the tunnel-shaped space 37 is not divided in the direction in which the wave advances, so the cooling performance of the battery cell 50 can be maintained at a high level.

The shape of the wave 31 in the corrugated sheet 30 may be, for example, a flat surface at the bottom 38 or the top 39 other than the sinusoidal cross section as shown in the figure, or the shape of the wave 31 may be flat. A plane may be sufficient as an inclined surface. Alternatively, the bottom 38 and the top 39 may be flat surfaces, and the slanted surface may be flat and have a trapezoidal cross section. Alternatively, the slanted surfaces of the waves 31 may have a serrated cross-section with both sides being flat. However, since the stress due to the deformation of the battery cell 50 is applied in the wave height direction of the wave 31, it is preferable to have a sinusoidal cross section as shown in the drawing in order to moderately relax the stress.

[1-4. Fourth modification]
FIG. 6 is a perspective view of a heat transfer suppression sheet 10 according to a fourth modified example of this embodiment. The heat transfer suppressing sheet 10 of this modification includes a flat sheet 20 containing an endothermic material and/or a heat insulating material and a corrugated sheet containing an endothermic material and/or a heat insulating material, as in the basic configuration described above. The flat sheet 20 and the corrugated sheet 30 are integrally formed.

However, in the heat transfer suppressing sheet 10 of this modified example, the flat sheet 20 is formed with a plurality of through holes 24 penetrating in the thickness direction thereof. As a result, air circulates toward the space 36 from the side of the flat sheet 20 that does not face the corrugated sheet 30 via the through holes 24, thereby further improving the cooling performance of the battery cells 50. .
The through holes 24 may also be provided in the corrugated sheet 30 . In this case, further improvement in cooling performance can be expected. Also, the through hole 24 may be elliptical, polygonal, or the like, in addition to the circular shape shown in the drawing. Furthermore, the size (opening area) of each through-hole 24 may be the same or may be different. Furthermore, the through-holes 24 may be formed in a grid pattern at equal intervals, or may be formed at random.

There is no limit to the opening ratio of the through-holes 24, that is, the ratio of the total opening area of the through-holes 24 to the area of the flat sheet 20 or the corrugated sheet 30 when the through-holes 24 are not formed. As the aperture ratio increases, the rigidity of the entire sheet decreases. Further, since the flat sheet 20 is in surface contact with the battery cell 50, if the aperture ratio is large, the effect of suppressing heat propagation in the event of an abnormality may be reduced. For this reason, it is appropriately set in consideration of the balance between strength, cooling performance, and the effect of suppressing heat propagation in the event of an abnormality.
Other configurations and effects are the same as those described in the basic configuration above.

<2. Constituent Material of Heat Transfer Suppressing Sheet>
The heat transfer suppression sheet 10 contains an endothermic material and/or a heat insulating material. That is, these may contain either one or both.

When the heat transfer suppressing sheet 10 is heated by the heat generated in a certain battery cell 50 when the battery cell 50 is abnormal, the heat transfer suppressing sheet 10 releases moisture while absorbing the heat. Due to this endothermic action, the amount of heat generated by the battery cells 50 can be reduced. As a result, when thermal runaway occurs in a certain battery cell 50 , heat propagation to other adjacent battery cells 50 is effectively suppressed.

In addition, the heat insulating material effectively reduces heat transfer in the heat transfer suppressing sheet 10 and exhibits a heat insulating effect.

Furthermore, the heat transfer suppression sheet 10 may contain various materials described later in addition to the heat absorbing material and the heat insulating material. Each constituent material will be described in detail below.

[2-1. endothermic material]
As a specific material for such an endothermic material, an inorganic hydrate or a dehydrating agent capable of releasing water by heating is preferable. The heat transfer suppressing sheet 10 can serve as a heat absorbing layer by containing a material that releases moisture when heated.
In the case where the heat transfer suppressing sheet 10 serves as a heat absorbing layer, when the heat transfer suppressing sheet 10 is heated by the heat generated in a certain battery cell 50 in the event of an abnormality in the battery cell 50, the heat transfer suppressing sheet 10 will absorb the heat. absorbs and releases water. Due to this endothermic action, the amount of heat generated by the battery cells 50 can be reduced. Therefore, when thermal runaway occurs in a certain battery cell 50 , it is possible to effectively suppress heat propagation to other adjacent battery cells 50 .

The inorganic hydrate preferably has a thermal decomposition initiation temperature of 200° C. or higher. Since the temperature range of a battery cell in an emergency is generally 200°C or higher, by using an inorganic hydrate with a thermal decomposition initiation temperature of 200°C or higher, moisture is effectively released and heat is released in an emergency. can be absorbed. As the dehydrating agent, it is preferable to use a dehydrating agent capable of dehydrating at a temperature of 150° C. or lower, which is the normal operating temperature of the battery cell 50 .

(2-1-1. Inorganic hydrate)
Examples of the inorganic hydrates include aluminum hydroxide (Al(OH) ₃ ), magnesium hydroxide (Mg(OH) ₂ ), calcium hydroxide (Ca(OH) ₂ ), 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 ), etc. .
These inorganic hydrates may be used alone or in combination of two or more.

The thermal decomposition initiation temperature of aluminum hydroxide is about 200°C, the thermal decomposition initiation temperature of magnesium hydroxide is about 330°C, the thermal decomposition initiation temperature of calcium hydroxide is about 580°C, and zinc hydroxide is about 200° C., iron hydroxide has a thermal decomposition initiation temperature of about 350° C., manganese hydroxide has a thermal decomposition initiation temperature of about 300° C., and zirconium hydroxide has a thermal decomposition initiation temperature of about 300° C. is about 300°C, and the thermal decomposition starting temperature of gallium hydroxide is about 300°C.

If two or more kinds of inorganic hydrates having different thermal decomposition initiation temperatures are used in combination, the battery cells 50 whose temperature has risen can be cooled in a wide temperature range, and heat transfer between the battery cells 50 during thermal runaway can be achieved. This is preferable because propagation can be effectively suppressed.

For example, aluminum hydroxide contains about 35% of water of crystallization. As shown in the following formula, the water of crystallization is released during thermal decomposition, thereby enhancing the flame-extinguishing function (endothermic reaction). can demonstrate.
2Al ₍ OH) ₃ → _Al2O3 + _3H2O
With this function, high-temperature heat generated in the battery cell 50 can be absorbed, and temperature rise of the battery cell 50 can be reduced.

For example, an inorganic hydrate with a thermal decomposition temperature of 200° C. or higher, such as aluminum hydroxide, has a temperature range that largely overlaps with the temperature rise on the surface of the battery cell 50 when thermal runaway of the battery cell 50 occurs. there is Therefore, heat transfer between the battery cells 50 can be effectively suppressed by causing a dehydration reaction (endothermic reaction) due to thermal decomposition as the temperature of the battery cells 50 rises in the event of an abnormality.

In particular, in the case of aluminum hydroxide, the thermal decomposition initiation temperature is relatively low among the above inorganic hydrates (thermal decomposition initiation temperature: about 200 ° C.), so the initial stage of an abnormality (relatively low temperature) Therefore, the battery cell 50 can be cooled, which is preferable.

A preferable upper limit of the amount of the inorganic hydrate compounded is 90% by mass, and a more preferable upper limit is 65% by mass, based on the total mass of the materials constituting the heat transfer suppressing sheet 10 . If this compounding amount exceeds 90% by mass, there is a possibility that sufficient strength as the heat transfer suppressing sheet 10 cannot be maintained.

(2-1-2. Dehydrating agent)
As the dehydrating agent, it is also preferable to use a dehydrating agent capable of dehydrating at a temperature of 150° C. or less. By having a dehydrating agent capable of dehydrating within the temperature range of normal temperature (approximately 20° C.) to a maximum of approximately 150° C., which is the temperature range of the battery cell 50 during normal use, the temperature of the battery cell 50 during normal use can be compared. Since the dehydrating agent releases water when the temperature rises to a relatively low temperature, the battery cells 50 can be effectively cooled during normal use.

Specific materials for obtaining the above effect include, for example, silica gel, activated alumina, activated carbon, zeolite, moisture adsorbents such as ion exchange resins, sulfate hydrate, sulfite hydrate, and phosphate water. hydrates, nitrate hydrates, acetate hydrates, metal hydrates and the like. These dehydrating agents may be used alone or in combination of two or more.

Examples of sulfate hydrates include ammonium aluminum sulfate dodecahydrate, sodium aluminum sulfate dodecahydrate, aluminum sulfate decahydrate, aluminum sulfate decahydrate, aluminum sulfate decahydrate, and aluminum sulfate. decahydrate, aluminum sulfate hexahydrate, potassium aluminum sulfate dodecahydrate, iron sulfate heptahydrate, iron sulfate nonahydrate, potassium iron sulfate dodecahydrate, magnesium sulfate heptahydrate, sulfuric acid sodium decahydrate, nickel sulfate hexahydrate, zinc sulfate heptahydrate, beryllium sulfate tetrahydrate, zirconium sulfate tetrahydrate and the like.
Examples of sulfite hydrates 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. monohydrate, magnesium hydrogen phosphate heptahydrate, zinc phosphate tetrahydrate, zinc dihydrogen phosphate dihydrate, and the like.

Nitrate hydrates include, for example, aluminum nitrate nonahydrate, zinc nitrate hexahydrate, calcium nitrate tetrahydrate, cobalt nitrate hexahydrate, bismuth nitrate pentahydrate, and zirconium nitrate pentahydrate. , cerium nitrate hexahydrate, iron nitrate hexahydrate, iron nitrate nonahydrate, nickel nitrate hexahydrate, magnesium nitrate hexahydrate and the like.
Acetate hydrates include, for example, zinc acetate dihydrate and cobalt acetate tetrahydrate.
Examples of metal hydrates include chloride salts such as cobalt chloride hexahydrate and iron chloride tetrahydrate, borax (sodium tetraborate pentahydrate, sodium tetraborate decahydrate), Examples include borate salts such as disodium octaborate tetrahydrate and zinc borate tripentahydrate.

For example, if zeolite, which has a large water adsorption amount on the high temperature side (75° C. to 150° C.) within a temperature range of 150° C. or lower, and silica gel, which has a small water adsorption amount on the high temperature side, are used together, the temperature rises. This 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 dehydration temperature range. Zeolite is not particularly limited in kind, and examples thereof include β-type zeolite, Y-type zeolite, ferrierite, ZSM-5-type zeolite, mordenite, fauxsite, zeolite A and zeolite L.

Zeolites are aluminosilicates with a three-dimensional network structure. Since zeolite that adsorbs moisture exists stably, it usually adsorbs moisture in the gaps of its three-dimensional network structure under room temperature conditions. However, the moisture adsorbed to the zeolite is desorbed from the zeolite by applying heat above a certain temperature.
However, since zeolite that does not adsorb moisture is unstable, dehydrated zeolite has a high adsorption effect, and thus adsorbs moisture again after the temperature drops.

For example, a dehydrating agent capable of dehydrating at a temperature of 150° C. or less, such as zeolite, has a temperature range that largely overlaps with the temperature rise on the surface of the battery cell 50 when performing charge-discharge cycles. As the temperature of the battery cell 50 rises, the battery cell 50 can be effectively cooled by releasing moisture.

Especially in the case of zeolite, after the battery cell 50 is cooled and the temperature of the dehydrating agent in the heat transfer suppressing sheet 1 is lowered, the moisture around the heat transfer suppressing sheet 1 is again adsorbed. It can be reused many times for repeated charging and discharging cycles.

A preferable upper limit of the amount of the dehydrating agent compounded is 90% by mass, and a more preferable upper limit is 65% by mass, based on the total mass of the materials constituting the heat transfer suppressing sheet 10 .
On the other hand, the preferable lower limit of the amount of the dehydrating agent is 10% by mass, and the more preferable lower limit is 35% by mass. If the amount is less than 10% by mass, a sufficient dehydration effect may not be obtained. Moreover, if this compounding amount exceeds 90% by mass, there is a possibility that sufficient strength as the heat transfer suppressing sheet 1 cannot be maintained.

The inorganic hydrate having a thermal decomposition initiation temperature of 200° C. or higher and the dehydrating agent capable of dehydrating at a temperature of 150° C. or lower described above may be used alone, but may be used in combination. preferable. By using these together, the effect of achieving both suppression of heat transfer in the event of an abnormality and cooling in normal use can be further exhibited. In other words, in addition to achieving both of the structural problems, it is possible to achieve both of the above problems from the material viewpoint by using a material that exerts an endothermic action both in abnormal conditions and in normal use.

[2-2. Insulation material]
As a specific material of the heat insulating material, at least one of inorganic fibers and inorganic particles may be included, and the effect of the heat insulating material can be exhibited by including either one of these. . However, by including both the inorganic fibers and the inorganic particles, the inorganic particles can divide the continuous voids in the structure generated by the entanglement of the inorganic fibers, so that the convective heat transfer in the heat transfer suppressing sheet 1 can be effectively performed. It becomes possible to reduce it, and the heat insulation effect can be exhibited more effectively.

(2-2-1. Inorganic fiber)
Examples of inorganic fibers include silica-alumina fibers, alumina fibers, silica fibers, rock wool, alkaline earth silicate fibers, glass fibers, zirconia fibers and potassium titanate whisker fibers. These inorganic fibers are preferable in terms of heat resistance, strength, availability, and the like. The inorganic fibers may be used singly or in combination of two or more. Among the inorganic fibers, silica-alumina fibers, alumina fibers, silica fibers, rock wool, alkaline earth silicate fibers, and glass fibers are particularly preferred from the viewpoint of handleability.

The cross-sectional shape of the inorganic fiber is not particularly limited, and examples thereof include circular cross-section, flat cross-section, hollow cross-section, polygonal cross-section, and core cross-section. Among them, 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 insulating properties are slightly improved.

A preferred lower limit for the average fiber length of the inorganic fibers is 0.1 mm, and a more preferred lower limit is 0.5 mm. On the other hand, the preferred upper limit of the average fiber length of inorganic fibers is 50 mm, and the more preferred upper limit is 10 mm. If the average fiber length of the inorganic fibers is less than 0.1 mm, the inorganic fibers are unlikely to be entangled with each other, and the resulting heat transfer suppressing sheet 10 may have reduced mechanical strength. On the other hand, if the thickness exceeds 50 mm, although a reinforcing effect can be obtained, the inorganic fibers cannot be tightly entangled with each other, or a single inorganic fiber will curl up, which tends to cause continuous voids, resulting in heat insulation. It may lead to a decline.

A preferable lower limit of the average fiber diameter of the inorganic fibers is 1 μm, a more preferable lower limit is 2 μm, and a still more preferable lower limit is 3 μm. On the other hand, the upper limit of the average fiber diameter of the inorganic fibers is preferably 10 µm, and the more preferred upper limit is 7 µm. If the average fiber diameter of the inorganic fibers is less than 1 μm, the mechanical strength of the inorganic fibers themselves may decrease. Moreover, from the viewpoint of 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 more than 10 μm, solid heat transfer through the inorganic fibers as a medium increases, which may lead to a decrease in heat insulating properties, and the formability of the heat transfer suppressing sheet 10 deteriorates. There is a risk.

This inorganic fiber can be used in a range of 10 to 70% by mass with respect to the total weight of the materials constituting the heat transfer suppressing sheet 1, if necessary.

(2-2-2. Inorganic particles)
Inorganic particles include, for example, _TiO2 powder, _SiO2 powder, BaTiO3 powder _, PbS powder, _ZrO2 powder, SiC powder, NaF powder and LiF powder. These inorganic particles may be used alone or in combination of two or more.

When inorganic particles are used in combination, preferred combinations include a combination of _TiO2 powder and _SiO2 powder, a combination of _TiO2 powder and BaTiO3 powder _, a combination of _SiO2 powder and BaTiO3 powder _, or a combination of TiO2 powder and BaTiO3 powder. ₂ powder, SiO ₂ powder and BaTiO ₃ powder.

Note that TiO ₂ powder has a high refractive index for infrared rays, and has the effect of improving heat insulation in a high temperature range. In addition, the SiO ₂ powder has a low solid heat transfer coefficient and is easy to create fine voids with fine particles, so it has the effect of suppressing convection and improving heat insulation in a low temperature range. Therefore, the combined use of TiO ₂ powder and SiO ₂ powder can be expected to provide heat insulation in a wide temperature range from low temperature to high temperature, so a combination of these is particularly preferred.

When both inorganic particles and inorganic fibers are included as materials constituting the heat transfer suppressing sheet 10, the amount of the inorganic fibers is preferably 50 mass with respect to the total weight of the materials constituting the heat transfer suppressing sheet 10. %, and a more preferable upper limit is 40% by mass. On the other hand, the preferred lower limit of the inorganic fiber content is 5% by mass, and the more preferred lower limit is 10% by mass. If the blending amount is less than 5% by mass, the reinforcing effect of the inorganic fiber cannot be obtained, and the heat transfer suppressing sheet 10 may be deteriorated in handleability and mechanical strength, and good moldability may not be obtained. There is On the other hand, when this compounding amount exceeds 50% by mass, a large number of continuous voids are present in the structure in which the inorganic fibers constituting the heat transfer suppressing sheet 10 are entangled, resulting in convective heat transfer, molecular heat transfer, and radiant heat transfer. increases, the heat insulating properties may deteriorate.

When both the inorganic particles and the inorganic fibers are included as the material forming the heat transfer suppressing sheet 10, the preferred upper limit of the amount of the inorganic particles is 95 mass with respect to the total weight of the materials forming the heat transfer suppressing sheet 10. %, and a more preferable upper limit is 90% by mass. On the other hand, the preferred lower limit of the amount of inorganic particles is 50% by mass, and the more preferred lower limit is 60% by mass. When the amount of the inorganic particles is within the above range, the effect of reducing convective heat transfer can be obtained by dividing the continuous voids in the entangled structure of the inorganic fibers while maintaining the reinforcing effect of the inorganic fibers.

A preferred lower limit for the average particle size of the inorganic particles is 0.5 μm, and a more preferred lower limit is 1 μm. On the other hand, the upper limit of the average particle size of the inorganic particles is preferably 20 μm, and more preferably 10 μm. If the average particle size of the inorganic particles is less than 0.5 μm, not only is it difficult to manufacture the heat transfer suppressing sheet 1, but the radiant heat is scattered insufficiently, and the heat transfer coefficient of the heat transfer suppressing sheet 1 increases (i.e. , the heat insulation is lowered). On the other hand, if the average particle size of the inorganic particles exceeds 20 μm, the voids generated in the heat transfer suppressing sheet 10 become extremely large, increasing convective heat transfer and molecular heat transfer, and in this case also increasing the heat transfer coefficient. Resulting in.

The shape of the inorganic particles is not particularly limited as long as the average particle size is within the above range. mentioned.

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

As materials capable of suppressing phonon conduction, substances having lattice defects in crystals or substances having complicated structures are generally known. TiO ₂ , SiO ₂ , and BaTiO ₃ described above are likely to have lattice defects and have a complicated structure, so they are considered to be effective not only for scattering radiant heat but also for scattering phonons.

Furthermore, inorganic particles having a reflectance of 70% or more for light having a wavelength of 10 μm or more can be preferably used as the inorganic particles. 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 more effectively reduced.

The solid heat transfer coefficient of the inorganic particles is preferably 20 W/m·K or less at room temperature. When inorganic particles having a solid heat transfer coefficient of more than 20 W/m·K at room temperature are used as a raw material, solid heat transfer becomes dominant in the heat transfer suppressing sheet 1, and the heat transfer coefficient increases (the heat insulating property decreases). There is a risk of doing so.

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

As a material for forming the heat transfer suppressing sheet 10, an organic binder may be used as necessary. Organic binders are useful for the purpose of improving strength during molding, and for example, polymer flocculants and acrylic emulsions can be preferably used.
The organic binder may be used in an amount of 0.5 to 5.0% by mass with respect to the total weight of the materials constituting the heat transfer suppressing sheet 1, if necessary.

Although the thickness of the corrugated sheet 30 constituting the heat transfer suppressing sheet 10 is not particularly limited, it is preferably in the range of 0.05 to 5 mm. Considering this, 1 mm or less is more preferable. If the thickness of the corrugated sheet 30 is less than 0.05 mm, the heat transfer suppressing sheet 10 cannot be provided with sufficient mechanical strength. On the other hand, if the thickness of the corrugated sheet 30 exceeds 5 mm, the molding itself of the heat transfer suppressing sheet 1 may become difficult.

The heat transfer suppression sheet 10 may contain an inorganic binder for the purpose of maintaining strength at high temperatures. Examples of inorganic binders include colloidal silica, synthetic mica, and montmorillonite. An inorganic binder may be used individually and may be used in combination of 2 or more types.

This inorganic binder can be used in a range of 1 to 10% by mass with respect to the total weight of the constituent materials of the heat transfer suppressing sheet 10, if necessary. The inorganic binder can be used, for example, by mixing it in raw materials or by impregnating it into the obtained heat insulating material.

Furthermore, an organic elastic substance may be used as a constituent material of the heat transfer suppressing sheet 10, if necessary. This organic elastic substance is useful in providing flexibility to the heat transfer suppressing sheet 10. For example, a synthetic rubber latex binder such as an emulsion of natural rubber, acrylonitrile-butadiene rubber (NBR), or styrene-butadiene rubber (SBR) is used. It can be used preferably. In particular, when the heat transfer suppressing sheet 10 is produced by a wet molding method, flexibility can be improved by using an organic elastic material.

The amount of the organic elastic substance compounded is preferably in the range of 0 to 5 mass % with respect to the total weight of the constituent materials of the heat transfer suppressing sheet 10 . If the blending amount of the organic elastic substance exceeds 5% by mass, the organic elastic substance will be burned off when used in a high temperature range of 700° C. or higher, and the voids will increase significantly, which may reduce the heat insulating properties. be.

<3. Seat structure>
The present invention includes a sheet structure in which the heat transfer suppressing sheets 10 described above are laminated.
A sheet structure 40 shown in FIG. 7 is configured by stacking a plurality of heat transfer suppression sheets 10 in the wave height direction of the corrugated sheet 30 . In the illustrated sheet structure 40, the phases of the corrugated sheets 30 in the respective heat transfer suppressing sheets 10 are matched (that is, the phases are the same), and three layers are laminated. By laminating the heat transfer suppression sheet 10, the rigidity is further improved, and the heat absorption performance and the heat insulation performance are also further improved as compared with the heat transfer suppression sheet 10 having a single layer. In addition, by stacking the heat transfer suppressing sheets 10 , it is possible to deal with various problems according to the distance between the adjacent battery cells 50 .

In the sheet structure 40 shown in FIG. 7, the space 36 formed by the flat sheet 20 and the corrugated sheet 30 faces the same direction, but at least one corrugated sheet 30 (for example, the center ) is directed in a different direction (for example, perpendicular direction) to the wave direction of the other corrugated sheet 30, and the direction of the air flow in the space 36 is changed to disperse and release heat for cooling. You may make it

Alternatively, as in the sheet structure 40 shown in FIG. 8, the corrugated sheets 30 adjacent to each other in the overlapping direction may be laminated such that the corrugations of the corrugated sheets 30 have opposite phases. . By configuring in this way, the rigidity of the seat structure 40 can be further improved.

Also in the sheet structure 40 , the connecting portions 35 may be formed in the corrugated sheet 30 .

<4. Assembled battery>
The present invention also includes an assembled battery in which the heat transfer suppressing sheet 10 and the sheet structure 40 are arranged between battery cells.
As shown in FIGS. 9 and 10, a plurality of battery cells 50 are arranged via the heat transfer suppression sheet 10, and the plurality of battery cells 50 are connected in series or in parallel (the connected state is shown in the drawing). are omitted, and both series and parallel connections may be used.) are stored in the battery case 60 to form the assembled battery 100 .

The illustrated assembled battery 100 is an example in which the corrugated sheets 30 of the heat transfer suppressing sheets 10 are arranged between the battery cells 50 such that the corrugated sheets 30 are oriented in the same direction. Note that the heat transfer suppressing sheet 10 can also be replaced with the sheet structure 40 . Alternatively, one may be the heat transfer suppressing sheet 10 and the other may be the sheet structure 40 .

Here, when assembling the assembled battery 100, the interval between the adjacent battery cells 50 has an assembly error. However, according to the heat transfer suppressing sheet 10 of the present invention, since the corrugated sheet 30 has flexibility due to the deformation of the corrugated sheet 30, the dimensional difference between the battery cells 50 can be absorbed, and the assembly is easy. become. In addition, as compared with the case where the heat transfer suppressing sheet 10 is composed only of the corrugated sheet 30, the rigidity is enhanced by the flat sheet 20, so that the ease of assembly is further improved.

FIG. 11 is a perspective view showing another form of the assembled battery 100. FIG. In the illustrated assembled battery 100 , the corrugated sheets 30 of the heat transfer suppressing sheets 10 are arranged between the battery cells 50 such that the corrugated sheets 30 are oriented in different directions (for example, orthogonal). As a result, the heat from the battery cells 50 can be dissipated and released in different directions, so that the heat can be released more effectively than in the case where heat is released only in one direction as shown in FIGS. 9 and 10. be able to.
Other configurations and effects are the same as those of the assembled battery 100 shown in FIGS.

<5. Method for manufacturing heat transfer suppression sheet>
Next, a method for manufacturing the heat transfer suppressing sheet 10 will be described with reference to FIG. 12 . Here, the heat transfer suppressing sheet 10 shown in FIG. 1 will be described as an example.

The heat transfer suppressing sheet 10 is manufactured by molding using a dry molding method or a wet molding method.

[5-1. When manufacturing using a dry molding method]
In the dry molding method, the endothermic material and/or the heat insulating material, and optionally the other materials mentioned above, are introduced in predetermined proportions into a mixer such as a V-type mixer. Then, after sufficiently mixing the materials charged into the mixer, the mixture is charged into a predetermined mold and pressed to obtain the flat heat transfer suppressing sheet material 10A. At the time of pressing, it may be heated as necessary.

The press pressure is preferably in the range of 0.98 MPa or more. If the press pressure is less than 0.98 MPa, the resulting heat transfer-suppressing sheet material 10A may fail to maintain its strength and collapse.

[5-2. When manufacturing using a wet molding method]
In the wet molding method, the heat-absorbing material and/or the heat-insulating material and, if necessary, the other materials described above are mixed and stirred in water to sufficiently disperse them, and then a flocculant is added to obtain primary aggregates. 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, the slurry containing the aggregates is put into a predetermined mold to obtain a wet heat transfer suppressing sheet material 10A, and then dried to obtain the desired heat transfer suppressing sheet material 10A.

As described above, the heat transfer suppressing sheet material 10A can be obtained by either the dry molding method or the wet molding method, but it is preferable to use the wet molding method from the viewpoint of the ease of integral molding and the mechanical strength.

[5-3. Integration of flat sheet 20 and corrugated sheet 30]
The obtained heat transfer suppressing sheet material 10A has a desired embossed shape as shown in FIG. to form a corrugated sheet 30 . Next, the flat rollers 72 arranged on the downstream side of the pair of embossing rollers 70 adhere the heat transfer suppressing sheet material 10A to be the flat sheet 20 to the upper and lower surfaces of the corrugated sheet 30 with an adhesive or the like. Thus, the heat transfer suppressing sheet 10 in which the corrugated sheet 30 is sandwiched between the pair of flat sheets 20 and integrated is obtained.

The wet heat transfer suppressing sheet material 10A can also be used as the heat transfer suppressing sheet material 10A. It is manufactured by pressing the sheet material 10A.

[5-4. Formation of connecting part]
In order to form the connecting portion 35 for reinforcing the wave 31 as shown in FIG. 4, two rows or a plurality of rows of units consisting of the embossing rollers 70 and the flat rollers 72 are arranged adjacent to each other with a certain interval. . Since there are no gear teeth between the units, a flat surface remains, and this flat surface becomes the connecting portion 35 .

5A, when manufacturing the heat transfer suppressing sheet 10 in which the connection part 35 is formed from the bottom part 38 of the wave 31 to the middle of the wave height, for example, a pair of upper and lower embossing rollers 70, 70 The embossing rollers 70, 70 having gear teeth matching the shape of the connecting portion 35 in FIG. 6 can be used.

It should be noted that the present invention is not limited to the above-described embodiments and modified examples, and can be modified, improved, etc. as appropriate.

10 Heat transfer suppression sheet 10A (for assembled battery) Heat transfer suppression sheet material 20 Flat sheet 22 Concavo-convex shape (on surface of flat sheet) 24 Through hole 26 Both end faces of corrugated sheet 30 Corrugated sheet 31 Wave 31a , 31b Wave crest 32 Concavo-convex shape 34 Solid material 35 Connections 36, 37 Space 38 Wave bottom 39 Wave top 40 Sheet structure 50 Battery cell 60 Battery case 70 Embossing roller 72 Flat Roller 100 Battery pack tp Flat sheet thickness tw Corrugated sheet thickness

Claims (18)

A heat transfer suppressing sheet for use in an assembled battery in which a plurality of battery cells are arranged via a heat transfer suppressing sheet and the plurality of battery cells are connected in series or in parallel,
A flat sheet containing a heat absorbing material and/or a heat insulating material is formed on both sides of a corrugated sheet containing a heat absorbing material and/or a heat insulating material,
Adjacent crests of waves are connected to each other only on one side of the corrugated sheet along the traveling direction of the waves by a connecting portion having a standing wall extending from the bottom to the top of the waves. Heat transfer suppression sheet for assembled battery. 2. The heat transfer suppressing sheet for an assembled battery according to claim 1, wherein the connecting portion is formed from the bottom to the top of the wave. 2. The heat transfer suppressing sheet for an assembled battery according to claim 1, wherein the connecting portion is formed from the bottom of the wave to the middle of the height of the wave. The heat transfer suppressing sheet for an assembled battery according to any one of claims 1 to 3 , wherein the thickness of the flat sheet is thicker than the thickness of the corrugated sheet. 5. The heat transfer suppressing sheet for an assembled battery according to claim 1 , wherein at least one of said corrugated sheet and said flat sheet has a plurality of through holes in the sheet thickness direction. At least one of the corrugated sheet and the flat sheet essentially contains the heat-absorbing material,
The heat transfer suppressing sheet for an assembled battery according to any one of claims 1 to 5 , wherein the endothermic material is an inorganic hydrate and/or a dehydrating agent. The endothermic material essentially contains the inorganic hydrate,
The heat transfer suppressing sheet for an assembled battery according to claim 6 , wherein the inorganic hydrate has a thermal decomposition initiation temperature of 200°C or higher. 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 8. The heat transfer suppressing sheet for an assembled battery according to Item 7 . The heat transfer suppressing sheet for an assembled battery according to claim 8 , wherein the inorganic hydrate is aluminum hydroxide. The endothermic material essentially contains the dehydrating agent,
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. 7. The heat transfer suppressing sheet for assembled battery according to claim 6 , which is at least one of the group. At least one of the corrugated sheet and the flat sheet essentially contains the heat insulating material,
The heat transfer suppressing sheet for assembled battery according to any one of claims 1 to 5 , wherein the heat insulating material is inorganic fibers and/or inorganic particles. The heat insulating material essentially contains the inorganic fiber,
12. The heat transfer suppressing sheet for an assembled battery according to claim 11 , wherein said 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. . The heat insulating material essentially contains the inorganic particles,
The heat transfer suppressing sheet for an assembled battery according to claim 11 , wherein the inorganic particles are at least one of _TiO2 and _SiO2 . A sheet structure formed by stacking and integrating a plurality of the heat transfer suppressing sheets for assembled battery according to any one of claims 1 to 13 . 15. The sheet structure according to claim 14 , wherein between the corrugated sheets adjacent to each other in the overlapping direction, the corrugations of the corrugated sheets have opposite phases to each other. 16. The sheet structure according to claim 14 or 15 , wherein at least one of the plurality of assembled battery heat transfer suppressing sheets has a corrugated direction different from that of the other corrugated sheets. The plurality of battery cells are the assembled battery heat transfer suppression sheet according to any one of claims 1 to 13 and / or the sheet structure according to any one of claims 14 to 16 . An assembled battery in which the plurality of battery cells are arranged in series or in parallel. 18. The method according to claim 17 , wherein at least one of the heat transfer suppressing sheet for assembled battery or the sheet structure interposed between the plurality of battery cells has a corrugated direction different from that of the other corrugated sheets. Batteries as described.

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