CN116711130A

CN116711130A - Heat transfer suppressing sheet for battery pack and battery pack

Info

Publication number: CN116711130A
Application number: CN202280009846.4A
Authority: CN
Inventors: 安藤寿; 高桥直己
Original assignee: Ibiden Co Ltd
Current assignee: Ibiden Co Ltd
Priority date: 2021-01-18
Filing date: 2022-01-14
Publication date: 2023-09-05
Also published as: JP2022110562A; JP7453163B2

Abstract

The present invention provides a heat transfer inhibiting sheet for a battery pack, which is used in a battery pack in which 2 or more battery cells are connected in series or in parallel, can inhibit heat transfer between the battery cells in abnormal situations, and can cool the battery cells in normal use, and a battery pack. The heat transfer suppressing sheet (A10) for a battery pack is used in a battery pack in which 2 or more battery cells are connected in series or parallel, and is interposed between the battery cells. The heat transfer suppressing sheet (A10) for a battery pack comprises a heat insulating material (A11) containing at least one of inorganic particles and inorganic fibers, and a coating material (A12) that coats at least a part of the heat insulating material (A11). A void (A14) is formed between the heat insulating material (A11) and the coating material (A12).

Description

Heat transfer suppressing sheet for battery pack and battery pack

Technical Field

The present invention relates to a heat transfer suppressing sheet for a battery pack that can be suitably used for a battery pack that constitutes a power source for driving an electric motor of an electric vehicle, a hybrid vehicle, or the like, for example, and a battery pack using the heat transfer suppressing sheet for a battery pack.

Background

In recent years, development of electric vehicles, hybrid vehicles, and the like driven by motors has been actively conducted in view of environmental protection. In such an electric vehicle, a hybrid vehicle, or the like, a battery pack is mounted in which 2 or more battery cells constituting a power source of a driving motor are connected in series or in parallel.

In this battery cell, a lithium ion secondary battery capable of realizing a high capacity and a high output as compared with a lead storage battery, a nickel hydrogen battery, or the like is mainly used, and when thermal runaway occurs in 1 battery cell due to internal short-circuiting, overcharge, or the like of the battery (i.e., in the case of "abnormal time"), heat transfer to another adjacent battery cell occurs, and thus thermal runaway of another battery cell may occur.

For example, patent document 1 discloses a power storage device capable of realizing effective heat insulation between 2 or more power storage elements such as lithium ion secondary batteries. In the power storage device described in patent document 1, a first plate material and a second plate material are arranged between a first power storage element and a second power storage element that are adjacent to each other. In addition, a low heat conduction layer, which is a layer of a substance having a lower heat conductivity than those of the first plate and the second plate, is formed between the first plate and the second plate.

In the power storage device of patent document 1 configured as described above, the radiation heat from the first power storage element toward the second power storage element or the radiation heat from the second power storage element toward the first power storage element is blocked by the first plate material and the second plate material. In addition, the movement of heat from one side of the 2 sheets toward the other side is suppressed by the low heat conduction layer.

However, in the above-described power storage device, since the heat insulating layer is provided only between the first power storage element and the second power storage element, the battery cells that emit heat during charge and discharge cycles cannot be cooled effectively.

Therefore, patent document 2 proposes a heat absorbing sheet for a battery pack, which can suppress heat transfer between each battery cell in an abnormal situation and can cool each battery cell in a normal use. The heat absorbing sheet described in patent document 2 contains 2 or more substances having different dehydration temperatures. And is constructed in such a manner that at least one of the above 2 or more substances can be dehydrated at the time of normal use of the battery cell and at least one other substance can be dehydrated at the time of abnormality of the battery cell.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2015-211013

Patent document 2: japanese patent application laid-open No. 2019-175806

Disclosure of Invention

Problems to be solved by the invention

In addition, when the battery cells of the assembled battery are subjected to charge/discharge cycles (i.e., when the assembled battery is used in normal operation), it is necessary to maintain the temperature of the cell surface at a predetermined value or less (e.g., 150 ℃ or less) in order to sufficiently exhibit the charge/discharge performance of the battery cells.

In addition, when an abnormal condition such as a temperature of 200 ℃ or higher occurs in the battery cell, it is necessary to cool the battery cell effectively.

As described above, there has been a recent demand for further improvement in heat transfer suppressing means capable of maintaining the surface temperature of the battery cell during normal use and capable of effectively cooling the battery cell during an abnormality at a high temperature.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a heat transfer control sheet for a battery pack, which is used in a battery pack in which 2 or more battery cells are connected in series or in parallel, and which can control heat transfer between each battery cell in an abnormal state and can cool each battery cell in normal use, and a battery pack.

Means for solving the problems

The above object of the present invention is achieved by the following configuration of [1] a heat transfer suppressing sheet for a battery pack.

[1] A heat transfer suppressing sheet for a battery pack, which is used in a battery pack in which 2 or more battery cells are connected in series or parallel, is interposed between the battery cells,

the heat transfer suppression sheet for a battery pack comprises:

a heat insulating material containing at least one of inorganic particles and inorganic fibers; and

A coating material for coating at least a part of the heat insulating material,

a void is formed between the heat insulating material and the coating material.

Further, preferred embodiments of the present invention relate to the following [2] to [13].

[2] The heat transfer control sheet for a battery pack according to item [1], wherein at least one of a surface of the heat insulating material facing the coating material and a surface of the coating material facing the heat insulating material has a concave portion and a convex portion.

[3] The heat transfer suppressing sheet for a battery pack as recited in [2], wherein,

the heat insulating material has a concave portion and a convex portion on a surface thereof facing the coating material,

the gap is formed between the concave portion and the coating material.

[4] The heat transfer control sheet for a battery pack according to [3], wherein the convex portion of the heat insulating material is bonded to the coating material.

[5] The heat transfer suppressing sheet for a battery pack as recited in [2], wherein,

the coating material has a concave portion and a convex portion on a surface facing the heat insulating material,

the void is formed between the recess and the heat insulating material.

[6] The heat transfer control sheet for a battery pack according to [5], wherein the convex portion of the coating material is bonded to the heat insulating material.

[7] The heat transfer suppressing sheet for a battery pack as recited in [2], wherein,

the void is formed between the concave portion of the heat insulating material and the concave portion of the coating material.

[8] The heat transfer control sheet for a battery pack according to [7], wherein the convex portion of the heat insulating material is bonded to the convex portion of the coating material.

[9] The heat transfer control sheet for a battery pack according to any one of [2] and [5] to [7], wherein the coating material is composed of an embossed polymer film or metal plate.

[10] The heat transfer control sheet for a battery pack according to any one of [2] to [9], wherein the void communicates with the outside of the heat insulating material and the coating material.

[11] The heat transfer suppressing sheet for a battery pack according to any one of [2] to [9], wherein,

the void is sealed at a temperature of less than 60 ℃,

the coating material is configured such that a communication port is formed at a temperature of 60 ℃ or higher to communicate the void portion with the outside of the coating material.

[12] The heat transfer control sheet for a battery pack according to item [11], wherein the heat insulating material and the coating material, or the coating material are bonded to each other by an adhesive that melts at 60 ℃ or higher, and 2 or more adhesives are used as the adhesive, and the 2 or more adhesives have different melting temperatures from each other in the 2 or more regions so that the 2 or more adhesives melt in stages in the 2 or more regions by an increase in temperature.

[13] The heat transfer control sheet for a battery pack according to item [11], wherein the heat insulating material and the coating material, or the coating material are bonded to each other by an adhesive that melts at 60 ℃ or higher, and the adhesive is applied in different application amounts to at least 2 regions so that the adhesive melts in stages in at least 2 regions by a rise in temperature.

The above object of the present invention is achieved by the following configuration of [14] of the battery pack.

[14] A battery pack comprising 2 or more cells connected in series or parallel, wherein the heat transfer suppressing sheet for a battery pack according to any one of [2] to [13] is interposed between the cells.

In the present specification, the schemes of [2] to [14] are referred to as "the 1 st invention group".

Further, preferred embodiments of the present invention relate to the following [15] to [20].

[15] The heat transfer control sheet for a battery pack according to [1], wherein the heat insulating material is entirely covered with the covering material.

[16] The heat transfer control sheet for a battery pack according to [15], wherein at least one of the inorganic particles and the inorganic fibers contained in the heat insulating material contains a material that releases water by heating.

[17] The heat transfer suppressing sheet for a battery pack as recited in [15] or [16], wherein,

the void is formed between the recess and the coating material.

[18] The heat transfer suppressing sheet for a battery pack as recited in [15] or [16], wherein,

the void is formed between the recess and the heat insulating material.

[19] The heat transfer suppressing sheet for a battery pack as recited in [15] or [16], wherein,

The heat insulating material has a concave portion and a convex portion on a surface facing the coating material,

the coating material has a concave portion and a convex portion on a surface facing the heat insulating material.

[20] The heat transfer control sheet for a battery pack according to [18] or [19], wherein the coating material is composed of an embossed polymer film or metal plate.

The above object of the present invention is achieved by the following configuration of [21] of the battery pack.

[21] A battery pack in which 2 or more battery cells are connected in series or parallel, wherein the heat transfer suppressing sheet for a battery pack according to any one of [15] to [20] is interposed between the battery cells.

The schemes of [15] to [21] in the present specification are referred to as "group 2" of the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

The heat transfer control sheet for a battery pack according to the present invention is a heat transfer control sheet used in a battery pack in which 2 or more battery cells are connected in series or in parallel, and is capable of controlling heat transfer between the battery cells in an abnormal situation and cooling the battery cells in a normal use.

The heat transfer control sheet for a battery pack according to the "1 st invention" is a heat transfer control sheet used in a battery pack in which 2 or more battery cells are connected in series or in parallel, and since concave portions and convex portions are formed on at least one surface of a heat insulating material and a coating material, a void portion is formed between the heat insulating material and the coating material, and air is present in the void portion. Therefore, the heat insulating effect is obtained by the air existing in the void, and the air having a raised temperature moves in the void, so that an excessive temperature rise can be prevented.

In addition, when the temperature of the battery cell is abnormal at a high temperature, the moisture contained in the heat insulating material evaporates, and therefore, the heat insulating material can be cooled by the vaporization heat.

In addition, in the case of abnormality of the battery pack, since concave portions and convex portions are formed on at least one surface of the heat insulating material and the coating material, the heated vapor is easily emitted to the outside. Therefore, heat transfer between the battery cells can be suppressed.

The heat transfer control sheet for a battery pack according to the "2 nd invention" is a heat transfer control sheet used in a battery pack in which 2 or more battery cells are connected in series or parallel, and has a coating material that completely coats a heat insulating material, and a void portion is formed between the heat insulating material and the coating material. Therefore, at the time of normal use of the battery pack, the moisture evaporated from the heat insulating material can be retained in the void portion, and the battery cells can be effectively cooled by the heat of vaporization at this time.

In addition, when the battery pack is abnormal, the pressure inside the coating material increases, and moisture generated from the heat insulating material is aggregated to form water droplets, so that the cooling effect of the battery cells can be obtained. Therefore, heat transfer between the battery cells can be suppressed.

In the assembled battery of the present invention, since the heat transfer suppressing sheet is interposed between 2 or more battery cells, each battery cell can be cooled during normal use, and heat transfer between the battery cells can be suppressed during abnormal use, thereby preventing occurrence of thermal runaway interlocking.

Drawings

Fig. 1 is a cross-sectional view schematically showing a heat transfer suppressing sheet for a battery pack according to embodiment 1 of the present invention.

Fig. 2 is a plan view schematically showing a heat insulating material used in the heat transfer suppression sheet for a battery pack according to embodiment 1 of the present invention.

Fig. 3 is a cross-sectional view schematically showing a battery pack to which a heat transfer suppression sheet for a battery pack according to embodiment 1 of the present invention is applied.

Fig. 4 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 2.

Fig. 5 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 3.

Fig. 6 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 1 to 3.

Fig. 7 is a plan view schematically showing still another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 1 to 3.

Fig. 8 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 4.

Fig. 9 is a plan view schematically showing a heat insulating material used in the heat transfer suppression sheet for a battery pack according to embodiment 4.

Fig. 10 is a cross-sectional view schematically showing a situation at the time of abnormality of the heat transfer control sheet for a battery pack according to embodiment 4.

Fig. 11 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 5.

Fig. 12 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 6.

Fig. 13 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 7.

Fig. 14 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 4 to 7.

Fig. 15 is a plan view schematically showing still another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 4 to 7.

Fig. 16 is a plan view schematically showing a heat transfer suppressing sheet for a battery pack using two adhesives having mutually different melting temperatures.

Fig. 17 is a plan view schematically showing another example of a heat transfer suppressing sheet for a battery pack using two adhesives having mutually different melting temperatures.

Fig. 18 is a plan view schematically showing still another example of a heat transfer suppressing sheet for a battery pack using two adhesives having mutually different melting temperatures.

Fig. 19 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 8.

Fig. 20 is a plan view schematically showing a heat insulating material used for the heat transfer suppression sheet for a battery pack according to embodiment 8.

Fig. 21 is a cross-sectional view schematically showing a battery pack to which a heat transfer suppression sheet for a battery pack according to embodiment 8 is applied.

Fig. 22 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 9.

Fig. 23 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 10.

Fig. 24 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 8 to 10.

Fig. 25 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 8 to 10.

Fig. 26 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 8 to 10.

Fig. 27 is a plan view schematically showing another example of the heat insulating material used for the heat transfer suppressing sheet for a battery pack according to embodiments 8 to 10.

Fig. 28 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 8 to 10.

Detailed Description

The present inventors have made intensive studies to provide a heat transfer suppressing sheet for a battery pack, which can suppress heat transfer between battery cells when abnormality occurs in high-temperature heat and can cool each battery cell when relatively low-temperature heat is generated during normal use.

As a result, the present inventors have found that the above-described problems can be solved by providing a heat insulating material containing at least one of inorganic particles and inorganic fibers, and a coating material that coats at least a part of the heat insulating material, and forming a void between the heat insulating material and the coating material.

Further, the present inventors have found that, as the "1 st invention group", it is more preferable that, when the concave portion and the convex portion are formed on at least one surface of the heat insulating material and the covering material, a void portion is formed between the heat insulating material and the covering material, and air is present in the void portion, whereby the above-mentioned problem can be more effectively solved.

That is, in a normal use in which the temperature of the battery cell is relatively low, for example, 60 ℃ or lower, the air existing in the void portion has a heat insulating effect, and the air having a high temperature moves in the void portion, so that an excessive temperature increase can be prevented.

In particular, in the case where the above-mentioned void portion communicates with the outside of the heat insulating material and the coating material, air having a temperature increased during normal use is discharged to the outside, and therefore, the battery cells can be effectively cooled.

In addition, when the temperature of the battery cells is abnormal due to a high temperature, the heated vapor is released to the outside through the void portion, and therefore, heat transfer between the battery cells can be suppressed.

On the other hand, even when the void is not in communication with the outside of the heat insulating material and the coating material, if the void is sealed during normal use and a communication port is formed to communicate the void with the outside of the coating material during abnormal use, moisture evaporated from the heat insulating material can be retained in the void during normal use, and thus a heat insulating effect can be obtained.

In addition, when the temperature of the battery cells is abnormal due to a high temperature, the communication port is formed to communicate the void portion with the outside of the coating material, and the heated vapor is discharged to the outside through the communication port, so that heat transfer between the battery cells can be suppressed.

Further, the present inventors have found that the above problem can be more effectively solved by completely sealing the heat insulating material with the coating material and forming a void between the heat insulating material and the coating material as the "invention group 2".

That is, in normal use where the temperature of the battery cell is relatively low, since a void portion exists between the heat insulating material and the coating material, moisture evaporated from the heat insulating material can be retained in the void portion, and the battery cell can be cooled effectively by utilizing the heat of vaporization at the time of evaporation.

In addition, when the temperature of the battery cell is abnormal at a high temperature, adsorbed water contained in the heat insulating material evaporates, or components contained in the material as the heat insulating material decompose to generate hydration water in the form of vapor. At this time, the heat insulating material is completely covered with the covering material, and thus the pressure in the gap between the heat insulating material and the covering material increases. As a result, the adsorbed water and the water of hydration in the vapor state are turned into water droplets and aggregated in the void portions, and the water droplets can cool the battery cells, thereby suppressing heat transfer between the battery cells.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The present invention is not limited to the embodiments described below, and may be modified and implemented arbitrarily without departing from the gist of the present invention.

In the following, the term "to" means that the lower limit value is equal to or higher than the upper limit value.

In the following embodiments, the embodiments of the present invention for describing the "1 st invention group" are referred to as "1 st embodiment" to "7 th embodiment", and the embodiments of the present invention for describing the "2 nd invention group" are referred to as "8 th embodiment" to "10 th embodiment".

First, the "1 st embodiment" to "7 th embodiment" of the "1 st invention group" will be described.

[ A1 ] Heat transfer suppressing sheet for Battery pack ]

First, a heat transfer control sheet for a battery pack according to embodiment 1 to embodiment 7 and a heat insulating material applicable to the heat transfer control sheet will be described. The heat insulating material, the coating material, and the like constituting the heat transfer inhibiting sheet for the assembled battery will be described in detail later. A method for manufacturing the heat transfer suppressing sheet for a battery pack according to the present embodiment will be further described.

Embodiments 1 to 3 described below are examples in which the void portion communicates with the outside of the heat insulating material and the coating material.

< embodiment 1 >

Fig. 1 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 1. Fig. 2 is a plan view schematically showing a heat insulating material used for the heat transfer suppressing sheet for a battery pack according to embodiment 1. Fig. 1 is a cross-sectional view taken along line A-A in the case of producing the heat transfer suppressing sheet a10 using the heat insulating material a11 shown in fig. 2. Hereinafter, the heat transfer inhibiting sheet a10 for a battery pack is sometimes simply referred to as a heat transfer inhibiting sheet a10.

The heat transfer suppressing sheet a10 for a battery pack according to the present embodiment includes a heat insulating material a11, and a coating material a12 that coats a front surface a11a and a rear surface a11b that are main surfaces of the heat insulating material a 11. The coating material a12 in the present embodiment does not cover the end face a11c of the heat insulating material a 11. As described below, when the heat transfer suppressing sheet a10 is laminated with the battery cells, the front surface a11a and the rear surface a11b of the heat insulating material a11 are surfaces facing the battery cells, and the end surface a11c is 4 surfaces parallel to the thickness direction of the heat transfer suppressing sheet a10.

The heat insulating material a11 contains, for example, inorganic particles and inorganic fibers containing crystal water or adsorbed water, which have a property of releasing moisture by heating. As shown in fig. 1 and 2, 2 or more groove-like recesses a13a are formed on the surface a11a of the heat insulating material a11 at equal intervals in 2 directions parallel to 2 opposite sides of the heat insulating material. The region where the concave portion a13a is not formed substantially constitutes the convex portion a13b.

The coating material a12 is, for example, a film, and the convex portion a13b of the heat insulating material a11 and the coating material a12 are bonded by an adhesive, not shown. Since the region where the concave portion a13a is formed is not in contact with the coating material a12, as a result, a void a14 is formed between the heat insulating material a11 and the coating material a 12. Since the recess a13a is formed so as to reach the end faces a11c of the insulating material a11 in the 4 directions, the void a14 communicates with the outside of the insulating material a11 and the coating material a12, that is, the outside of the heat transfer inhibiting sheet a10.

Fig. 3 is a cross-sectional view schematically showing a battery pack to which a heat transfer suppression sheet for a battery pack according to embodiment 1 is applied. The battery pack a100 includes a battery case a30, 2 or more battery cells a20 stored in the battery case a30, and a heat transfer suppressing sheet a10 interposed between the battery cells a 20. More than 2 battery cells a20 are connected in series or in parallel with each other by a busbar or the like, not shown.

The battery cell a20 is, for example, a lithium ion secondary battery, but is not particularly limited thereto, and may be applied to other secondary batteries.

In the heat transfer suppressing sheet a10 configured as described above, when the temperature of the battery cell a20 increases in a temperature range in normal use, that is, in a relatively low temperature range from normal temperature (about 20 ℃) to about 60 ℃, heat is also transferred to the heat insulating material a11. In the present embodiment, the heat insulating material a11 has the void a14, and thus air is present in the void a14, so that the transfer of heat emitted from the battery cell a20 can be suppressed.

In addition, as the temperature increases, the temperature of the air in the void a14 increases, but since the void a14 communicates with the outside of the heat transfer suppressing sheet a10, the heated air is discharged to the outside of the heat transfer suppressing sheet a 10. Accordingly, since fresh air is always introduced into the void portion a14, the temperature increase of the heat transfer suppressing sheet a10 itself can be suppressed, and the temperature increase of the battery cell a20 can also be suppressed.

In addition, in the case where the temperature of the battery cell a20 abnormally increases, higher heat is also transferred to the heat insulating material a11. In the present embodiment, the heat insulating material a11 contains inorganic particles containing crystal water or adsorbed water, and since the crystal water or adsorbed water is a material that emits moisture by heating, the moisture evaporates from the inorganic particles by heating the heat insulating material a11. At this time, the heat insulating material a11 extracts the vaporization heat and cools the battery cell a20, and therefore the heat transfer inhibition sheet a10 can cool the battery cell.

The high-temperature vapor is not retained in the void a14 and is emitted from the end face a11c side of the heat insulating material a11 to the outside of the heat transfer suppressing sheet a10, so that the heat transfer suppressing sheet a10 can cool the battery cells a20 more effectively.

After the battery cells a20 are effectively cooled, when the use (i.e., charge and discharge) of the battery pack a100 is stopped, the water vapor remaining in the void portion a14 is cooled to form water droplets, which are absorbed into the heat insulating material a11 over time. Then, at the next use, the moisture in the heat insulating material a11 evaporates again, and thereby the heat insulating material a11 extracts the vaporization heat, and the battery cell a20 can be cooled.

< embodiment 2 >

In fig. 4 and 5 showing the following embodiments 2 and 3, the same or equivalent parts as those of embodiment 1 are denoted by the same reference numerals in the drawings, and the description thereof is omitted or simplified. Note that, since the following embodiments 2 and 3 can be used in place of the heat transfer suppressing sheet a10 described in the assembled battery a100 shown in fig. 3, the effects and the like will be described assuming that the heat transfer suppressing sheets of embodiments 2 and 3 are applied to the assembled battery a 100.

The heat transfer control sheet a50 for a battery pack according to embodiment 2 includes a heat insulating material a51, and a coating material a52 that coats the front surface a51a and the rear surface a51b of the heat insulating material a 51. The end face a51c of the heat insulating material a51 is not covered with the covering material a52 as in embodiment 1.

In embodiment 2, the front surface a51a and the rear surface a51b of the heat insulating material a51 are flat, and no concave portion or convex portion is formed. On the other hand, the coating material a52 is formed by embossing the entire surface of a film, and has a concave portion a53a recessed in a groove shape in a direction away from the heat insulating material a51 and a convex portion a53b protruding toward the heat insulating material a51 formed on a surface facing the heat insulating material a 51. The convex portion a53b of the coating material a52 and the heat insulating material a51 are bonded by an adhesive, not shown, and a void a14 is formed between the concave portion a53a and the heat insulating material a 51.

In the heat transfer suppressing sheet a50 configured as described above, the void portion a14 communicates with the outside of the heat transfer suppressing sheet a50, and therefore the same effects as those of embodiment 1 described above can be obtained even in normal use and abnormal cases. In the case where the heat transfer suppressing sheet a50 is formed using the coating material a52 shown in embodiment 2, the coating material a52 having a film as a material is easy to process, and therefore the concave portion a53a and the convex portion a53b having desired shapes can be easily formed.

< embodiment 3 >

The heat transfer control sheet a60 for a battery pack according to embodiment 3 includes a heat insulating material a11, and a coating material a52 that coats the front surface a11a and the rear surface a11b of the heat insulating material a 11. The end face a11c of the insulating material a11 is not covered with the covering material a52 as in embodiment 1 and embodiment 2.

In this embodiment, similarly to embodiment 1, the heat insulating material a11 is formed with the concave portion a13a and the convex portion a13b. In addition, as in embodiment 2, in the coating material a52, a film embossed on the entire surface is formed, and a concave portion a53a recessed in a groove shape in a direction away from the heat insulating material a11 and a convex portion a53b protruding toward the heat insulating material a11 are formed on a surface facing the heat insulating material a 11.

In the present embodiment, when the heat insulating material a11 and the coating material a52 are bonded, the shape of the coating material a52 is designed so that the position of the groove-shaped concave portion a53a of the coating material a52 coincides with the position of the groove-shaped concave portion a13a of the heat insulating material a11, and the position of the convex portion a53b of the coating material a52 coincides with the position of the convex portion a13b of the heat insulating material a 11.

The convex portion a53b of the coating material a52 and the convex portion a13b of the heat insulating material a11 are bonded by an adhesive, not shown, and a void a14 is formed between the concave portion a53a of the coating material a52 and the concave portion a13a of the heat insulating material a 11.

The heat transfer control sheet a60 thus constructed can obtain the same effects as those of the above-described embodiments 1 and 2 even in normal use and abnormal cases. Further, since the recess a13a and the recess a53a constitute the void a14, the volume of the void a14 increases as compared with the heat transfer suppressing sheet of embodiment 1 and embodiment 2. Therefore, the temperature of the air in the void portion a14 is less likely to rise, and the heat insulating effect of the heat transfer suppressing sheet a60 is improved. In addition, since the heated air and the high-temperature vapor are easily moved, the effect of cooling the battery cell a20 can be further improved.

In embodiment 2 and 3, the shape of the groove-shaped concave portion a53a and the convex portion a53b in the coating material a52 is, for example, the same as the shape of the surface of the heat insulating material a11 shown in fig. 5, but the present invention is not limited thereto. For example, a coating material having a corrugated shape with grooves extending only in a pair of side directions of the heat insulating material, or a coating material having a corrugated shape with grooves extending in a diagonal direction of the heat insulating material may be used.

In embodiments 1 to 3, the coating material is disposed only on the front and rear surfaces of the heat insulating material, but the coating material may cover a part of the cross section or the entire cross section in addition to the front and rear surfaces of the heat insulating material. However, it is necessary to set the shape of the void portion or to form an opening in a part of the coating material so that at least a part of the void portion formed between the coating material and the heat insulating material communicates with the outside of the heat transfer suppressing sheet.

The heat transfer inhibiting sheets for a battery pack according to embodiments 1 to 3 are described in order above. In embodiments 1 to 3, examples in which the heat insulating material a11 shown in fig. 2 is used are given, but the shape of the heat insulating material is not particularly limited, and for example, heat insulating materials having recesses of various shapes shown below may be used.

Next, another example of the heat insulating material used for the heat transfer suppressing sheet for a battery pack according to embodiment 1 to 3 is shown.

< other examples of Heat insulating Material >

As shown in fig. 6, 2 or more groove-shaped recesses a13a extending in a direction parallel to the 1-side of the heat insulating material a21 are formed at equal intervals on the surface a21a of the heat insulating material a21, and the region where the recesses a13a are not formed substantially constitutes the protruding portion a13b. Since the recess a13a is formed so as to reach the end face a21c of the heat insulating material a21, when the coating material is adhered to the surface a21a of the heat insulating material a21, the void communicates with the outside of the heat transfer suppressing sheet.

The heat insulating material a21 thus constituted can be applied to the heat transfer suppressing sheet for a battery pack of the above-described 1 st to 3 rd embodiments, and the same effects as those of the above-described 1 st to 3 rd embodiments can be obtained.

< still other examples of Heat insulation Material >

In the heat insulating material 11 shown in fig. 2 and the heat insulating material a21 shown in fig. 6, all the concave portions a13a reach the end portions of the heat insulating material, and all the void portions formed between the heat insulating material and the coating material are configured to communicate with the outside, but the present invention is not limited thereto.

As shown in fig. 7, 2 or more groove-like recesses a13a extending in one direction are regularly formed in the surface a31a of the heat insulating material a31, and the recesses a13a reach the pair of opposite end surfaces a31c of the heat insulating material a 31. Further, groove-shaped recesses a13c and groove-shaped recesses a13d extending in the same direction as the recesses a13a are formed between adjacent recesses a13 a. When the end faces a31c of the heat insulating material a31 are not reached at the both end portions of the recess a13c and the coating material is adhered to the surface a31a of the heat insulating material a31, the void formed between the recess a13c and the coating material is not communicated with the outside of the heat transfer suppressing sheet.

In the recess a13d, one end portion reaches the end face a31c of the heat insulating material 31A, and the other end portion does not reach the end face a31c of the heat insulating material a 31. Therefore, when the coating material is adhered to the surface a31a of the heat insulating material a31, the void formed between the concave portion a13d and the coating material communicates with the outside of the heat transfer suppressing sheet.

In the heat transfer suppressing sheet using the heat insulating material a31 having such a structure, the void portions formed between the concave portions a13a and a13d and the coating material communicate with the outside of the heat transfer suppressing sheet, and therefore the same effects as those of the above-described embodiments 1 to 3 can be obtained.

Since the void formed between the recess a13c and the coating material is not communicated with the outside, the heated air and the high-temperature vapor are not discharged to the outside and remain in the void. However, when the charge and discharge of the battery pack a100 are stopped and the battery cells a20 are cooled, the vapor retained in the void portions is also cooled to form water droplets, which are absorbed into the heat insulating material a31 over time. Therefore, at the next use, the moisture in the heat insulating material a31 can be evaporated again, and therefore the cooling effect by the vaporization heat can be maintained.

The above embodiments 1 to 3 are examples in which the void portion communicates with the outside of the heat insulating material and the coating material, but the present invention is not limited to such a configuration. For example, if the structure is such that the void is sealed during normal use and a communication port for communicating the void with the outside of the coating material is formed during an abnormality, the battery cells can be cooled more effectively during normal use and during an abnormality, and heat transfer between the battery cells can be suppressed.

Embodiments 4 to 7 will be described below.

Note that, since the following embodiments 4 to 7 can be used instead of the heat transfer suppressing sheet a10 described in the assembled battery a100 shown in fig. 3, the effects and the like will be described assuming that the heat transfer suppressing sheets of embodiments 4 to 7 are applied to the assembled battery a 100.

< embodiment 4 >

Fig. 8 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 4. Fig. 9 is a plan view schematically showing a heat insulating material used in the heat transfer suppression sheet for a battery pack according to embodiment 4. In embodiment 4 shown in fig. 8 and 9, the difference from embodiment 1 shown in fig. 1 and 2 is only the shape of the recess a13a and the presence or absence of communication with the outside. Therefore, in fig. 8 and 9, the same or equivalent parts as those of embodiment 1 are denoted by the same reference numerals in the drawings, and the description thereof is omitted or simplified.

As shown in fig. 8 and 9, 2 or more concave portions a13a are regularly formed on the surface a71a of the heat insulating material a71 constituting the heat transfer suppressing sheet a70, and the region where the concave portions a13a are not formed substantially constitutes the convex portion a13b.

The concave portion a13a is rectangular in a plan view, for example, and as shown in fig. 9, concave portions in which the longitudinal direction is parallel to one side of the heat insulating material a71 and concave portions in which the longitudinal direction is orthogonal to one side of the heat insulating material a71 are alternately arranged.

The coating material a12 is, for example, a polymer film that melts at 60 ℃ or higher, and the convex portion a13b of the heat insulating material a71 and the coating material a12 are bonded by an adhesive, not shown. In this embodiment, an adhesive made of an organic substance or an inorganic substance is used, and the adhesive has a property of melting at 60 ℃ or higher.

Since the region where the concave portion a13a is formed is not in contact with the coating material a12, as a result, a void a14 is formed between the heat insulating material a71 and the coating material a 12. Further, by bonding the convex portion a13b located around the void a14 to the coating material a12, the void a14 is necessarily sealed at a temperature of less than 60 ℃.

In the heat transfer suppressing sheet a70 configured as described above, when the temperature of the battery cell a20 increases in a temperature range in normal use, that is, in a relatively low temperature range from normal temperature (about 20 ℃) to about 150 ℃, heat is also transferred to the heat insulating material a71. In the present embodiment, the heat insulating material a71 contains inorganic particles containing crystal water or adsorbed water, and since the crystal water or adsorbed water is a material that emits moisture by heating, the moisture evaporates from the inorganic particles by heating the heat insulating material a71. In addition, some of the evaporated moisture remains in the void a14, and the other portion is discharged from the end face a71c side of the heat insulating material a71. At this time, the heat insulating material a71 extracts the vaporization heat and cools the battery cell a20, and therefore the heat transfer inhibition sheet a70 can effectively cool the battery cell.

After the battery cells a20 are effectively cooled, when the use (i.e., charge and discharge) of the battery pack a100 is stopped, the water vapor retained in the void a14 is cooled to form water droplets, which are absorbed into the heat insulating material a71 over time. Then, at the next use, the moisture in the heat insulating material a71 evaporates again, and the heat insulating material a71 extracts the vaporization heat, thereby cooling the battery cell a20, and repeating such a cycle.

Fig. 10 is a cross-sectional view schematically showing a situation at the time of abnormality of the heat transfer control sheet for a battery pack according to embodiment 4. The front surface a71a of the heat insulating material a71 shows a state in which a part of the coating material a12 is melted, and the rear surface a71b shows a state in which an adhesive that adheres the coating material a12 to the heat insulating material a71 is melted due to a rise in temperature.

As shown in fig. 10, when the temperature of the battery cell a20 is increased to 200 ℃ or higher, for example, at the time of abnormality, the coating material a12 melts, and a communication port a15 is formed which communicates the void a14 with the outside. In addition, even when the coating material a12 that does not melt at high temperature is used, if the adhesive melts, a communication port a15 that communicates the void a14 with the outside of the heat transfer inhibiting sheet a70 is formed.

When the communication port a15 is formed in this way, vapor evaporated from the inorganic particles and retained in the void a14 to be high temperature is discharged to the outside of the heat transfer inhibiting sheet a70 through the communication port a 15. Therefore, even when the battery cells a20 cause thermal runaway, heat transfer between the battery cells a20 can be effectively suppressed.

The polymer film and the adhesive used in the present embodiment each have a property of melting at any temperature of 60 ℃ or higher. That is, in a temperature range of less than 60 ℃, the void 14 is necessarily in a sealed state. The polymer film and the adhesive have various melting temperatures depending on the kind thereof, and thus may be selected from polymer films or adhesives having a desired melting temperature in a range of 60 ℃ or more as needed.

The temperature at which the communication port for communicating the void portion a14 with the outside of the coating material a12 is formed is preferably 80 ℃ or higher, more preferably 100 ℃ or higher.

On the other hand, the upper limit of the temperature at which the communication port for communicating the void portion a14 with the outside of the coating material a12 is formed, that is, the upper limit of the temperature at which the polymer film or the adhesive is melted is not particularly limited, but is preferably 500 ℃ or less, more preferably 350 ℃ or less, further preferably 300 ℃ or less, and particularly preferably 250 ℃ or less.

< embodiment 5 >

In fig. 11 showing embodiment 5 described below, the same or equivalent parts as those of embodiment 4 described above are denoted by the same reference numerals in the drawings, and the description thereof is omitted or simplified.

The heat transfer suppressing sheet a80 for a battery pack according to embodiment 5 includes a heat insulating material a71, and a coating material a12 that coats a front surface a71a, a rear surface a71b, and an end surface a71c, which are main surfaces of the heat insulating material a 71. In the present embodiment, the concave portion a13a and the convex portion a13b are also formed on the end face a71c of the heat insulating material a 71. That is, the entire surface of the heat insulating material a71 is covered with a covering material a12 formed in a bag shape by an adhesive agent or the like, not shown, and the heat insulating material a71 is completely sealed by the covering material a12.

The heat transfer control sheet a80 thus constructed can obtain the same effects as those of embodiment 4 above even in normal use. In embodiment 5, since the heat insulating material a71 is entirely covered with the covering material a12, when the heat insulating material a71 is heated and the moisture evaporates from the inorganic particles during normal use, all the evaporated moisture remains in the void portion a14 and is not released to the outside from the heat transfer inhibiting sheet a 80. However, since the moisture evaporates, the heat insulating material a71 extracts the vaporization heat and cools the battery cell a20, and the heat transfer suppressing sheet a80 can effectively cool the battery cell.

In embodiment 5, since the evaporated moisture is not released to the outside, most of the evaporated moisture is absorbed again into the heat insulating material a71 when the use of the battery pack is stopped. Therefore, according to the heat transfer inhibiting sheet a80 for a battery pack of embodiment 5, the effect of cooling the battery cells a20 can be maintained for a long period of time.

In addition, in the case of abnormality, the adhesive that adheres the coating materials a12 to each other melts or the coating material a12 melts, and thus, as in the case shown in fig. 10, a communication port is formed between the void portion a14 and the outside, and therefore, the same effect as in embodiment 4 can be obtained.

< embodiment 6 >

Fig. 12 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 6. In fig. 12 showing embodiment 6 described below, the same or equivalent parts as those of embodiment 2 shown in fig. 4 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

In the heat transfer suppressing sheet a90 for a battery pack according to embodiment 6, the surface of the heat insulating material a51 is flat, and no concave and convex portions are formed. On the other hand, the coating material a52 is formed of a film, and has an embossed surface, and a concave portion a53a recessed in a direction away from the heat insulating material a51 and a convex portion a53b protruding from the heat insulating material a51 are formed on a surface facing the heat insulating material a 51. The convex portion a53b of the coating material a52 and the heat insulating material a51 are bonded by an adhesive, not shown, and a sealed void a14 is formed between the concave portion a53a and the heat insulating material a 51.

The heat transfer control sheet a90 thus constructed can obtain the same effects as those of embodiment 4 above even in normal use and abnormal situations. By using the coating material a52 shown in embodiment 6, the heat transfer suppressing sheet is configured to cover the entire surface of the heat insulating material a51, and the effect of cooling the battery cells a20 can be maintained for a long period of time as in embodiment 5.

< embodiment 7 >

Fig. 13 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 7. In fig. 13 showing embodiment 7 described below, the same or equivalent parts as those of embodiment 3 shown in fig. 5 are denoted by the same reference numerals in the drawings, and the description thereof is omitted or simplified.

The heat transfer control sheet a95 for a battery pack according to embodiment 7 includes a heat insulating material a71 and a coating material a52 that coats the entire surface of the heat insulating material a 71. In the present embodiment, the heat insulating material a71 is formed with a concave portion a13a and a convex portion a13b. Also, on the surface of the coating material facing the heat insulating material a71, a concave portion a53a recessed in a direction away from the heat insulating material a71 and a convex portion a53b protruding toward the heat insulating material a71 are formed. The convex portion a53b of the coating material a52 and the convex portion a13b of the heat insulating material a71 are bonded by an adhesive, not shown, and a sealed void a14 is formed between the concave portion a53a of the coating material a52 and the concave portion a13a of the heat insulating material a 71.

The heat transfer control sheet a95 thus constructed can obtain the same effects as those of embodiment 4 above even in normal use and abnormal cases. Further, since the recess a13a and the recess a53a constitute the void a14, the volume of the void a14 increases as compared with the heat transfer suppressing sheets for battery packs according to embodiments 4 to 6. Therefore, the moisture is easily evaporated from the heat insulating material a71, and the effect of cooling the battery cell a20 can be further improved in normal use.

In embodiment 7, the coating material a52 is formed to cover the end face a71c of the heat insulating material a71, but the end face a71c of the heat insulating material a71 may be open as in embodiment 4. By opening the end face a71c, a part of the evaporated moisture is released to the outside in normal use, so that the moisture in the heat insulating material a71 is more easily evaporated, and the cooling effect by the vaporization heat can be improved.

In addition, even when the coating material a52 that does not melt at high temperature is used in the case of abnormality, if the adhesive melts, the communication port a15 that communicates the void a14 with the outside of the heat transfer inhibiting sheet a95 can be formed, and therefore, the effect of cooling the battery cell a20 can be obtained.

The heat transfer inhibiting sheet for a battery pack according to embodiments 4 to 7 is described above in order. Next, another example of the heat insulating material used for the heat transfer suppressing sheet for a battery pack according to embodiments 4 to 7 is shown.

< other examples of Heat insulating Material >

Fig. 14 is a plan view schematically showing another example of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiments 4 to 7. In embodiments 4, 5 and 7, examples in which the heat insulating material a71 shown in fig. 9 is used are given, but the shape of the heat insulating material is not particularly limited.

As shown in fig. 14, 2 or more concave portions a13a are regularly formed on the surface a41a of the heat insulating material a41, and the region where the concave portions a13a are not formed substantially constitutes the convex portion a13b.

The concave portion a13a in the present embodiment is rectangular in a plan view, for example, and all the concave portions a13a are arranged so that the longitudinal direction thereof is parallel to one side of the heat insulating material a 41.

The heat insulating material a41 thus configured can be applied to the heat transfer suppressing sheet for a battery pack of the above-described 4 th to 7 th embodiments, and the same effects as those of the above-described 4 th to 7 th embodiments can be obtained.

< still other examples of Heat insulation Material >

In the heat insulating material a71 shown in fig. 9 and the heat insulating material a41 shown in fig. 14, all the concave portions a13a are sealed with a coating material, but the present invention is not limited thereto.

As shown in fig. 15, 2 or more concave portions a13a are regularly formed on the surface a61a of the heat insulating material a61, and the region where the concave portions a13a are not formed substantially constitutes the convex portion a13b. However, the recess a13c formed in the vicinity of the end face a61c of the heat insulating material a61 reaches the end face a61c of the heat insulating material a 61.

For example, in the case where the heat insulating material a71 in embodiment 4 is replaced with the heat insulating material a61, the recess a13c formed in the vicinity of the end face a61c of the heat insulating material a61 does not constitute a closed void. However, since a closed void is formed between a part of the recess a13a and the coating material a12, the same effects as those of the above-described embodiments 4 to 7 can be obtained.

Next, the thickness of the heat insulating material, the coating material, the adhesive, and the heat transfer suppressing sheet constituting the heat transfer suppressing sheet for a battery pack according to the present embodiment will be described in detail.

< Heat insulating Material >

The heat insulating material used in the heat transfer control sheet for a battery pack according to the present embodiment contains at least one of inorganic particles and inorganic fibers.

The inorganic particles are preferably inorganic hydrates or aqueous porous bodies. When the temperature of the inorganic hydrate reaches or exceeds the thermal decomposition start temperature, the inorganic hydrate thermally decomposes and releases the crystal water contained in the inorganic hydrate, thereby cooling the battery cell a 20. In addition, the porous body is formed by discharging crystal water, and effective heat insulation can be obtained by numerous air holes.

As the inorganic particles, a single inorganic particle may be used, or 2 or more kinds of inorganic hydrate particles may be used in combination. Since the thermal decomposition initiation temperature of the inorganic hydrate varies depending on the type, the battery cell a20 can be cooled in multiple stages by combining 2 or more kinds of inorganic hydrate particles.

Specific examples of the inorganic hydrate include aluminum hydroxide (Al (OH) ₃ ) Magnesium hydroxide (Mg (OH) ₂ ) Calcium hydroxide (Ca (OH) ₂ ) Zinc hydroxide (Zn (OH) ₂ ) Ferric hydroxide (Fe (OH)) ₂ ) Manganese hydroxide (Mn (OH) ₂ ) Zirconium hydroxide (Zr (OH) ₂ ) Gallium hydroxide (Ga (OH) ₃ ) Etc.

Further, as the fibrous inorganic hydrate, fibrous calcium silicate hydrate and the like are mentioned.

Specific examples of the aqueous porous material include zeolite, kaolinite, montmorillonite, acid clay, diatomaceous earth, sepiolite, wet silica, dry silica, aerogel, mica, and vermiculite.

Examples of the inorganic fibers include alumina fibers, silica fibers, aluminum silicate fibers, asbestos, magnesium silicate fibers, alkaline earth silicate fibers, glass fibers, zirconia fibers, and potassium titanate fibers. Among these inorganic fibers, magnesium silicate fibers can be suitably used as a material that releases moisture by heating.

The inorganic fibers may be single inorganic fibers, or 2 or more inorganic fibers may be used in combination.

In addition to the inorganic particles and the inorganic fibers, an organic fiber, an organic binder, and the like may be mixed as needed in the heat insulating material. They are useful for the purpose of reinforcing heat insulating materials and improving moldability.

The inorganic particles and inorganic fibers contained in the heat insulating material do not necessarily need to contain a material that releases moisture by heating. Since a certain amount of moisture is necessarily contained in the production of the heat insulating material, the effect of cooling the battery cells a20 can be obtained by evaporating the moisture contained in the heat insulating material when the temperature of the battery cells a20 increases in normal use and abnormal conditions.

In the present embodiment, the heat insulating material may contain at least one of inorganic particles and inorganic fibers, and the content of the inorganic particles is preferably 20 mass% or more and 80 mass% or less, and the content of the inorganic fibers is preferably 5 mass% or more and 70 mass% or less, with respect to the total mass of the heat transfer inhibiting sheet. By using such a content, the shape retention, the extrusion force resistance, and the wind pressure resistance can be improved by the inorganic fibers, and the holding ability of the inorganic particles can be ensured.

The heat transfer control sheet of the present embodiment may be mixed with an organic fiber, an organic binder, or the like as necessary. They are useful for the purpose of enhancing the heat transfer inhibiting sheet and improving the moldability.

< coating Material >

As the coating material, a polymer film or a film (metal plate) made of metal can be used.

Examples of the polymer film include polyimide, polycarbonate, PET, p-phenylene sulfide, polyetherimide, crosslinked polyethylene, flame retardant chloroprene rubber, polyvinylidene fluoride, hard vinyl chloride, polybutylene terephthalate, PTFE, PFA, FEP, ETFE, hard PCV, flame retardant PET, polystyrene, polyethersulfone, polyamideimide, polyacrylonitrile, polyethylene, polypropylene, polyamide, and the like.

The melting point of the polymer film is 60-600 ℃. When the polymer film melts at 60 ℃ or higher, the coating material (polymer film) can seal the void at a temperature lower than 60 ℃. In addition, when the polymer film melts at an arbitrary temperature of 60 ℃ or higher, a communication port for communicating the void portion with the outside of the coating material can be formed, which is preferable.

In the case of using a polymer film as a coating material in this embodiment, the melting temperature of the polymer film is preferably 60 ℃ or higher, more preferably 80 ℃ or higher, and still more preferably 100 ℃ or higher.

On the other hand, the melting temperature of the polymer film is preferably 500 ℃ or less, more preferably 350 ℃ or less, further preferably 300 ℃ or less, particularly preferably 250 ℃ or less.

Examples of the metal film include aluminum foil, stainless steel foil, and copper foil.

< adhesive >

In the present embodiment, as a method of sealing the gap formed between the heat insulating material and the coating material, a method of bonding the heat insulating material and the coating material, or a method of bonding the coating materials to each other may be applied.

Examples of the adhesive for bonding the heat insulating material and the coating material include adhesives made of urethane, polyethylene, polypropylene, polystyrene, nylon, polyester, vinyl chloride, vinylon, acrylic resin, silicone, and the like.

The adhesive may be used as an adhesive for bonding the coating materials to each other.

When the adhesive melts at 60 ℃ or higher, the coating material preferably seals the void at a temperature lower than 60 ℃. In addition, when the adhesive melts at an arbitrary temperature of 60 ℃ or higher, a communication port for communicating the void portion with the outside of the coating material can be formed, which is preferable.

In the case of using an adhesive in this embodiment, the melting temperature of the adhesive is preferably 60 ℃ or higher, more preferably 80 ℃ or higher, and still more preferably 100 ℃ or higher.

On the other hand, the melting temperature of the adhesive is preferably 500 ℃ or less, more preferably 350 ℃ or less, further preferably 300 ℃ or less, particularly preferably 250 ℃ or less.

As a method of sealing the gap formed between the heat insulating material and the coating material, a method of coating the entire heat insulating material with the coating material may be applied.

Examples of the method of coating the entire heat insulating material with the coating material include lamination (dry lamination, thermal lamination), laminator, vacuum packaging, vacuum lamination, shrink packaging, candy packaging, and the like.

As the adhesive for bonding the heat insulating material and the covering material, or the covering material to each other, 2 or more adhesives having different melting temperatures from each other so that the two or more regions are melted stepwise by the rise of temperature may be used. As an example of using 2 or more kinds of adhesives, description will be made below with reference to the drawings. The following examples shown in fig. 16 to 18 are modification examples of the heat transfer suppressing sheet a70 for a battery pack according to embodiment 4 shown in fig. 8 and 9.

As shown in fig. 16, in the heat transfer suppressing sheet a110 for a battery pack, the adhesive a16b is used in the peripheral portion near the end surface in the region of the convex portion a13b of the heat insulating material a71, and the adhesive a16a is used in the region further inside than the region. The adhesives a16a and a16b have different melting temperatures, and specifically, the melting temperature of the adhesive a16b is designed to be higher than the melting temperature of the adhesive a16a. The melting temperature of the coating material is designed to be higher than the melting temperature of the adhesive a16 b.

In the heat transfer suppressing sheet a110 thus configured, as the 1 st stage, the gap between each concave portion a13a and the coating material is sealed at a temperature lower than the melting temperature of the adhesive a16 a. Therefore, when the heat insulating material a71 is heated and the moisture evaporates from the inorganic particles, all the evaporated moisture stays in the void portion and is not emitted to the outside from the heat transfer suppressing sheet a110, but the heat insulating material a71 is cooled by the evaporation of the moisture by capturing the vaporization heat.

Thereafter, as the stage 2, when the temperature of the battery cell is further increased to be equal to or higher than the melting temperature of the adhesive a16a and lower than the melting temperature of the adhesive a16b, the region to be bonded by the adhesive a16a is partitioned, and the volume of the void portion increases, so that the moisture is easily evaporated from the heat insulating material a 71. In addition, the heated vapor is not retained at a certain position but can move in a wider area than the stage 1, so the heat transfer inhibiting sheet a110 can effectively cool the battery cells.

Further, as the 3 rd step, when the temperature of the battery cell reaches the melting temperature of the adhesive a16b or higher, the region to be bonded by the adhesive a16b is partitioned, and a communication port for communicating the void portion with the outside of the heat transfer inhibiting sheet a110 is formed. As a result, the high-temperature vapor retained inside the region of the adhesive a16b is released at one time. Therefore, even in the case where the battery cells cause thermal runaway, heat transfer between the battery cells can be effectively suppressed.

As shown in fig. 17, in the heat transfer control sheet a120, an adhesive a16b having a higher melting temperature is used in the peripheral portion in the region of the convex portion a13b of the heat insulating material a71, similarly to the heat transfer control sheet a110 shown in fig. 16. However, the adhesive a16a having a lower melting temperature is used only in a part of the peripheral portion, which is the same as the inner region.

In the heat transfer suppressing sheet a120 thus configured, as the 1 st stage, the gap between the concave portion a13a and the coating material is sealed at a temperature lower than the melting temperature of the adhesive a16a. Therefore, like the heat transfer suppressing sheet a110 shown in fig. 16, moisture evaporates from the heat insulating material a71 into the void portion, and the heat insulating material a71 is cooled by capturing the vaporization heat.

Thereafter, as the 2 nd stage, the temperature of the battery cell further increases to be equal to or higher than the melting temperature of the adhesive a16a, and the region bonded by the adhesive a16a is partitioned, so that the moisture is easily evaporated from the heat insulating material a 71. Since the adhesive a16a having a low melting temperature is used only in a part of the peripheral portion, this region serves as a communication port for communicating the void portion with the outside of the heat transfer inhibiting sheet a 110. Therefore, as shown by the arrows in fig. 17, high-temperature vapor is emitted from the communication ports, and therefore, heat transfer between the battery cells can be effectively suppressed.

As shown in fig. 17, when the adhesive a16a having a lower melting temperature as in the inner region is used only in a part of the peripheral portion, the position where high-temperature vapor (moisture) is emitted can be easily controlled. Therefore, water can be prevented from flowing to a predetermined member in the battery pack.

Fig. 18 is a plan view schematically showing still another example of a heat transfer inhibiting sheet for a battery pack using two adhesives having mutually different melting temperatures.

As shown in fig. 18, in the heat transfer suppressing sheet a130, an adhesive a16b having a high melting temperature is used in the peripheral portion in the region of the convex portion a13b of the heat insulating material a71, as in the heat transfer suppressing sheet a120 shown in fig. 17. However, the adhesive a16a having a low melting temperature is used only in a part of the peripheral portion, and this region becomes a communication port at a high temperature. Further, an adhesive a16c having the same melting temperature as that of the adhesive a16b is used in a region spaced apart from the peripheral portion at a predetermined interval on the inner side than the region in which the adhesive a16b is used. Even in the region where the adhesive a16c is used, the adhesive a16a having a low melting temperature is partially used on the opposite side of the region serving as the communication port.

In the heat transfer control sheet a130 configured as described above, in the 1 st stage, similarly to the heat transfer control sheet a120 shown in fig. 17, moisture evaporates from the heat insulating material a71 toward the void portion, and the heat insulating material a71 is cooled by capturing the vaporization heat.

Thereafter, as the 2 nd stage, when the adhesive a16a melts, a water release path is formed as indicated by an arrow in fig. 18. As a result, the high-temperature vapor moves along the discharge path and is discharged to the outside through the communication port, and therefore the cooling effect can be further improved.

The adhesives a16a, a16b, and a16c may all have different melting temperatures, and the area where each adhesive is used may be arbitrarily determined according to the purpose.

As described above, the heat transfer suppressing sheets a110, a120, a130 shown in fig. 16 to 18 are designed such that the adhesive can be melted in stages in 2 or more regions due to the increase in the temperature of the battery cells.

Therefore, the timing of the emission of the vapor retained in the void portion can be adjusted, the vapor discharge port can be provided at an arbitrary position, and an arbitrary emission path can be provided.

In order to obtain the above-described effect, the adhesive may be designed so that the adhesive melts in stages in 2 or more regions due to the temperature rise, and a method of applying the adhesive in different amounts in 2 or more regions may be used in addition to a method of using adhesives having different melting temperatures.

In fig. 16 to 18, the case where the adhesive (which adheres the heat insulating material a71 to the coating material) is melted in stages in the heat transfer suppressing sheet in which the coating material is adhered to the front surface side and the rear surface side of the heat insulating material a71 has been described, but the present invention is not limited to this case. For example, even in a configuration in which the heat insulating material a71 is entirely covered with a covering material, a method of adjusting the melting temperature or the coating amount of the adhesive according to the region can be applied. Specifically, in the vicinity of the end surfaces of the heat insulating material a71, when the coating materials are adhered to each other, the same effect as that of the heat transfer suppressing sheet a110 can be obtained by setting the melting temperature of the adhesive for adhering the coating materials to each other to be high and the melting temperature of the adhesive for adhering the heat insulating material a71 to the coating materials to be low.

< thickness of Heat transfer inhibiting sheet >

In the present embodiment, the thickness of the heat transfer suppressing sheet is not particularly limited, but is preferably in the range of 0.05 to 6 mm. If the thickness of the heat transfer inhibiting sheet is less than 0.05mm, sufficient mechanical strength cannot be imparted to the heat transfer inhibiting sheet. On the other hand, if the thickness of the heat transfer suppressing sheet is greater than 6mm, the molding itself of the heat transfer suppressing sheet may become difficult.

Next, a method for manufacturing the heat transfer suppression sheet for a battery pack according to the present embodiment will be described.

< method for producing Heat transfer control sheet >

The heat insulating material used for the heat transfer control sheet of the present embodiment can be produced by, for example, mold molding a material containing at least one of inorganic particles and inorganic fibers by a dry molding method or a wet molding method. As the dry molding method, for example, a compression molding method (dry compression molding method) and an extrusion molding method (dry extrusion molding method) can be used.

(method for producing Heat insulating Material by Dry Press Molding)

In the dry press molding method, inorganic particles, inorganic fibers, and if necessary, organic fibers, an organic binder, and the like are charged into a mixer such as a V-type mixer at a predetermined ratio. After the materials charged into the mixer are sufficiently mixed, the mixture is charged into a predetermined mold and press-molded to obtain a heat insulating material. In the press molding, heating may be performed as needed.

The heat insulating material having concave and convex portions can be formed, for example, by a method of pressing using a die having concave and convex portions at the time of press molding.

The pressing pressure at the time of press molding is preferably in the range of 0.98MPa to 9.80 MPa. If the pressing pressure is less than 0.98MPa, the strength of the obtained heat insulating material cannot be ensured, and the heat insulating material may be damaged. On the other hand, if the pressing pressure is more than 9.80MPa, the workability may be lowered by excessive compression, the solid heat transfer may be increased by an increase in bulk density, and the heat insulating property may be lowered.

In addition, in the case of using the dry press molding method, ethylene-vinyl acetate copolymer (EVA: ethylene-Vinylacetate copolymer) is preferably used as the organic binder, but in the case of using the dry press molding method, any organic binder that is generally used may be used without particular limitation.

(method for producing Heat insulation Material by Dry extrusion molding)

In the dry extrusion molding method, water is added to inorganic particles and inorganic fibers, and if necessary, organic fibers and an organic binder as a binder, and the like, and kneaded by a kneader to prepare a paste. Thereafter, the obtained paste is extruded from a slit-shaped nozzle using an extrusion molding machine, and further dried, whereby a heat insulating material can be obtained. In the case of using the dry extrusion molding method, methylcellulose, water-soluble cellulose ether, or the like is preferably used as the organic binder, and in the case of using the dry extrusion molding method, the organic binder may be used without any particular limitation as long as it is a commonly used organic binder.

For example, as a method for producing the heat insulating material a21 having concave portions and convex portions shown in fig. 6 by a dry extrusion molding method, for example, a method of extruding the above paste as a raw material from a slit-shaped nozzle having a desired groove shape is given.

The concave portion a13a in the heat insulating material shown in fig. 2, 7, 9, and 14 can be formed by, for example, extruding the paste as a raw material from a slit nozzle, and cutting the surface of the sheet before drying, which is obtained by this method, so as to form a desired concave portion.

(method for producing Heat insulating Material by Wet Molding method)

In the wet molding method, inorganic particles, inorganic fibers, and if necessary, an organic binder as a binder are mixed in water and stirred by a stirrer to prepare a mixed solution. Thereafter, the obtained mixed liquid was poured into a former having a filter mesh formed on the bottom surface, and the mixed liquid was dehydrated through the mesh, whereby a wet sheet was produced. Thereafter, the obtained wet sheet is heated and pressurized at the same time, whereby a heat insulating material can be obtained.

Before the heating and pressurizing step, the wet sheet may be subjected to a through-air drying process in which hot air is introduced to dry the sheet, but the wet sheet may be heated and pressurized without the through-air drying process.

In the case of using the wet molding method, an acrylic emulsion of polyvinyl alcohol (PVA: polyVinyl Alcohol) may be used as the organic binder.

As a method for producing a heat insulating material having concave portions and convex portions by wet molding, for example, a method in which a wet sheet is press-molded using a mold having concave and convex portions before heating and pressurizing is given.

(method for producing coating Material)

As the coating material, a general-purpose polymer film manufactured to have a desired thickness or a film made of metal may be used, and the film may be formed with irregularities by press molding using a mold having irregularities.

(method for producing Heat transfer suppressing sheet)

The heat transfer suppressing sheet of the present embodiment can be produced, for example, by applying an adhesive to the heat insulating material or the coating material obtained as described above, and bonding the heat insulating material and the coating material.

Further, as a method of coating the entire heat insulating material with a coating material, for example, a method of sandwiching the heat insulating material between 2 pieces of coating materials cut larger than the surface of the heat insulating material, and thermally bonding the coating materials to each other around the heat insulating material or bonding the coating materials with an adhesive may be mentioned.

A2 Battery pack

The assembled battery of the present embodiment is an assembled battery in which 2 or more battery cells are connected in series or in parallel, and the heat transfer suppressing sheet for an assembled battery of the present embodiment is interposed between the battery cells. Specifically, for example, as shown in fig. 3, the assembled battery a100 is formed by arranging 2 or more battery cells a20 in parallel, connecting them in series or in parallel, and storing them in a battery case a30, and the heat transfer suppressing sheet a10 is interposed between the battery cells a 20.

In such a battery pack a100, the heat transfer inhibiting sheet a10 is interposed between the battery cells a20, so that the battery cells a20 can be cooled during normal use.

In addition, in the case where one of the 2 or more battery cells a20 is thermally out of control and has a high temperature, and swelling or ignition occurs, the heat transfer between the battery cells a20 can be suppressed by the presence of the heat transfer suppressing sheet a10 of the present embodiment. Therefore, the occurrence of thermal runaway interlocking can be suppressed, and adverse effects on the battery cell a20 can be suppressed to the minimum.

Next, the "8 th embodiment" to "10 th embodiment" of the "2 nd invention group" will be described.

B1 Heat transfer suppressing sheet for assembled battery

Embodiments 8 to 10 of the heat transfer suppressing sheet for a battery pack according to the present embodiment will be described in order. Hereinafter, another example of the heat insulating material of the present embodiment, a heat insulating material constituting the heat transfer suppressing sheet for a battery pack of the present embodiment, a coating material, and the like will be described. A method for manufacturing the heat transfer suppressing sheet for a battery pack according to the present embodiment will be further described.

< embodiment 8 >

Fig. 18 is a cross-sectional view schematically showing a heat transfer suppression sheet for a battery pack according to embodiment 8. Fig. 20 is a plan view schematically showing a heat insulating material used for the heat transfer suppression sheet for a battery pack according to embodiment 8. Hereinafter, the heat transfer inhibiting sheet B40 for a battery pack is sometimes simply referred to as a heat transfer inhibiting sheet B40.

The heat transfer suppressing sheet B40 for a battery pack of the present embodiment includes a heat insulating material B71, and a coating material B12 that coats a front surface B71a and a rear surface B71B that are main surfaces of the heat insulating material B71. In the present embodiment, the coating material B12 completely coats the heat insulating material B71. As described below, when the heat transfer suppressing sheet B40 is laminated with the battery cells, the front surface B71a and the rear surface B71B of the heat insulating material B71 are surfaces facing the battery cells, and the end surface B71c is 4 surfaces parallel to the thickness direction of the heat transfer suppressing sheet B40.

The heat insulating material B71 contains, for example, inorganic particles and inorganic fibers containing crystal water or adsorbed water, which have a property of releasing moisture by heating. As shown in fig. 19 and 20, 2 or more concave portions B13a are regularly formed on the surface B71a of the heat insulating material B71, and the region where the concave portions B13a are not formed substantially constitutes the convex portion B13B.

The concave portion B13a is rectangular in a plan view, for example, and as shown in fig. 20, concave portions having a longitudinal direction parallel to one side of the heat insulating material B71 and concave portions having a longitudinal direction orthogonal to one side of the heat insulating material B71 are alternately arranged.

The coating material B12 is, for example, a polymer film, and the convex portion B13B of the heat insulating material B71 and the coating material B12 are bonded by an adhesive, not shown, composed of an organic substance or an inorganic substance.

Since the region where the concave portion B13a is formed is not in contact with the coating material B12, a void portion B14 is formed between the heat insulating material B71 and the coating material B12 as a result. The coating material B12 completely coats the heat insulating material B71.

Fig. 21 is a cross-sectional view schematically showing a battery pack to which a heat transfer suppression sheet for a battery pack according to embodiment 8 is applied. The battery pack B100 includes a battery case B30, 2 or more battery cells B20 stored in the battery case B30, and a heat transfer inhibiting sheet B40 interposed between the battery cells B20. More than 2 battery cells B20 are connected in series or in parallel with each other through a busbar or the like, not shown.

The battery cell B20 is, for example, a lithium ion secondary battery, but is not particularly limited thereto, and may be applied to other secondary batteries.

In the heat transfer suppressing sheet B40 configured as described above, when the temperature of the battery cell B20 increases in a temperature range in normal use, that is, in a relatively low temperature range from normal temperature (about 20 ℃) to about 150 ℃, heat is also transferred to the heat insulating material B71. In the present embodiment, the heat insulating material B71 contains inorganic particles containing crystal water or adsorbed water, and since the crystal water or adsorbed water is a material that emits moisture by heating, the moisture evaporates from the inorganic particles by heating the heat insulating material B71. The evaporated moisture is retained in the void B14. At this time, the heat insulating material B71 extracts the vaporization heat and cools the battery cell B20, and therefore the heat transfer inhibition sheet B40 can effectively cool the battery cell B.

After the battery cells B20 are effectively cooled, when the use (i.e., charge and discharge) of the battery pack B100 is stopped, the water vapor retained in the void B14 is cooled to form water droplets, which are absorbed into the heat insulating material B71 over time. Then, at the next use, the moisture in the heat insulating material B71 evaporates again, and thereby the heat insulating material B71 extracts the vaporization heat, and the battery cell B20 is cooled, and the cycle is repeated.

As described above, in the present embodiment, the heat insulating material B71 is completely covered with the covering material B12, and most of the evaporated moisture is absorbed again into the heat insulating material B71, so that the effect of cooling the battery cells B20 can be maintained for a long period of time in normal use.

< embodiment 9 >

In fig. 22 and 23 showing the following 9 th to 10 th embodiments, the same or equivalent parts to those of the 8 th embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted or simplified. Note that, since all of the embodiments described below can be used in place of the heat transfer suppressing sheet B40 described in the assembled battery B100 shown in fig. 21, the effects and the like will be described assuming that the heat transfer suppressing sheets of the 9 th to 10 th embodiments are applied to the assembled battery B100.

The heat transfer control sheet B60 for a battery pack according to embodiment 9 includes a heat insulating material B71 and a coating material B12 that completely coats the heat insulating material B71. That is, the entire surface of the heat insulating material B71 is covered with a covering material B12 formed in a bag shape by an adhesive agent or the like, not shown, and the heat insulating material B71 is completely sealed by the covering material B12.

In the present embodiment, the heat insulating material B71 is formed with a concave portion B13a and a convex portion B13B. In addition, in the coating material, a concave portion B53a recessed in a direction away from the heat insulating material B71 and a convex portion B53B having a shape protruding toward the heat insulating material B71 are formed on a surface facing the heat insulating material B71. The convex portion B53B of the coating material B52 and the convex portion B13B of the heat insulating material B71 are bonded by an adhesive, not shown, and a void portion B14 is formed between the concave portion B53a of the coating material B52 and the concave portion 13a of the heat insulating material B11.

The heat transfer control sheet B60 thus constructed can obtain the same effects as those of embodiment 8 above even in normal use and abnormal situations. Further, since the hollow B14 is formed by the concave portion B13a and the concave portion B53a, the volume of the hollow B14 increases as compared with the heat transfer suppressing sheet B40 for a battery pack according to embodiment 8. Therefore, the adsorbed water or the water of hydration is easily evaporated from the heat insulating material B71, and the effect of cooling the battery cell B20 can be further improved in normal use.

< embodiment 10 >

In the heat transfer control sheet B80 for a battery pack according to embodiment 10, the front surface B71a, the rear surface B71B, and the end surface B71c of the heat insulating material B71 are covered with a covering material (metal plate) B82 made of metal. That is, the coating material B82 completely coats and seals the heat insulating material B71.

The heat transfer control sheet B80 thus constructed can obtain the same effects as those of the above-described embodiments 8 and 9 even in normal use.

The heat transfer inhibiting sheets for a battery pack according to embodiments 8 to 10 are described above in order. In the above-described embodiments 8 to 10, examples were given in which the heat insulating material B71 shown in fig. 20 was used, but the shape of the heat insulating material is not particularly limited. For example, even when the concave portion and the convex portion are not formed in the heat insulating material, if the concave portion and the convex portion are formed in the coating material, a void portion can be formed between the heat insulating material and the coating material, and therefore the same effects as those of the above-described embodiments 8 to 10 can be obtained.

Next, another example of the heat insulating material used for the heat transfer suppressing sheet for a battery pack according to embodiments 8 to 10 is shown.

< other examples of Heat insulating Material >

Fig. 24 to 28 are plan views schematically showing other examples of the heat insulating material used in the heat transfer suppressing sheet for a battery pack according to embodiment 8 to 10.

As shown in fig. 24, 2 or more concave portions B13a are regularly formed on the surface B41a of the heat insulating material B41, and the region where the concave portions B13a are not formed substantially constitutes the convex portion B13B.

The concave portions B13a in the present embodiment are rectangular in a plan view, for example, and all the concave portions B13a are arranged so that the longitudinal direction thereof is parallel to one side of the heat insulating material B41.

As shown in fig. 25, 2 or more concave portions B13a are regularly formed on the surface B61a of the heat insulating material B61, and the region where the concave portions B13a are not formed substantially constitutes the convex portion B13B. However, unlike the heat insulator B41 shown in fig. 6, the concave portion B13c formed in the vicinity of the end face B61c of the heat insulator B61 reaches the end face B61c of the heat insulator B61.

As shown in fig. 26, 2 or more groove-like concave portions B13a are formed on the surface B11a of the heat insulating material B11 at equal intervals in 2 directions parallel to 2 opposite sides of the heat insulating material B11. The region where the concave portion B13a is not formed substantially constitutes the convex portion B13B.

As shown in fig. 27, 2 or more groove-like concave portions B13a extending in a direction parallel to the 1-side of the heat insulating material B21 and having both ends reaching the end face B21c are formed at equal intervals on the surface B21a of the heat insulating material B21, and the region where the concave portions B13a are not formed substantially constitutes the convex portion B13B.

As shown in fig. 28, 2 or more groove-shaped recesses B13a extending in one direction are regularly formed in the surface B31a of the heat insulating material B31, and both end portions of the recesses B13a reach a pair of opposite end surfaces B31c of the heat insulating material B31. Further, a groove-shaped recess B13c and a groove-shaped recess B13d extending in the same direction as the recess B13a are formed between the adjacent recesses B13 a. When both ends of the recess B13c do not reach the end face B31c of the heat insulating material B31 and the coating material is adhered to the surface B31a of the heat insulating material B31, the void formed between the recess B13c and the coating material is not communicated with the outside of the heat transfer inhibiting sheet.

In the recess B13d, one end portion reaches the end face B31c of the heat insulating material B31, and the other end portion does not reach the end face B31c of the heat insulating material B31.

The above examples show examples of the heat insulating material having various concave portions and convex portions, and the heat transfer suppressing sheet for a battery pack according to any of the above embodiments 8 to 10 can be applied to the same effects as those of the above embodiments 8 to 10.

< Heat insulating Material >

The inorganic particles are preferably inorganic hydrates or aqueous porous bodies. When the temperature of the inorganic hydrate reaches or exceeds the thermal decomposition start temperature, the inorganic hydrate thermally decomposes and releases the crystal water contained in the inorganic hydrate, thereby cooling the battery cell B20. In addition, the porous body is formed by discharging crystal water, and effective heat insulation can be obtained by numerous air holes.

As the inorganic particles, a single inorganic particle may be used, or 2 or more kinds of inorganic hydrate particles may be used in combination. Since the thermal decomposition initiation temperature of the inorganic hydrate varies depending on the type, the battery cell B20 can be cooled in multiple stages by combining 2 or more kinds of inorganic hydrate particles.

The inorganic particles and inorganic fibers contained in the heat insulating material do not necessarily need to contain a material that releases moisture by heating. Since a certain amount of moisture is necessarily contained in the production of the heat insulating material, the effect of cooling the battery cells B20 can be obtained by evaporating the moisture contained in the heat insulating material when the temperature of the battery cells B20 increases during normal use and during abnormal conditions.

< coating Material >

< adhesive >

In the present embodiment, an adhesive may be used as a method of bonding the heat insulating material and the coating material, and a method of bonding the coating materials to each other.

Examples of the adhesive include adhesives made of urethane, polyethylene, polypropylene, polystyrene, nylon, polyester, vinyl chloride, vinylon, acrylic resin, silicone, and the like.

< thickness of Heat transfer inhibiting sheet >

< method for producing Heat transfer control sheet >

(method for producing Heat insulating Material by Dry Press Molding)

(method for producing Heat insulation Material by Dry extrusion molding)

Examples of the method for producing a heat insulating material having concave and convex portions by dry extrusion include a method in which the surface of a sheet before drying after extrusion from a slit nozzle is cut into a desired concave-convex shape.

(method for producing Heat insulating Material by Wet Molding method)

(method for producing coating Material)

As a method for producing a coating material having concave portions and convex portions, the above-mentioned polymer film or a metal film which is generally used and is produced to a desired thickness may be used, and a method of press molding using a die having concave and convex portions may be used.

(method for producing Heat transfer suppressing sheet)

The heat transfer inhibiting sheet of the present embodiment can be manufactured, for example, as follows: the heat insulating material is manufactured by sandwiching the heat insulating material between 2 sheets of coating material cut larger than the surface of the heat insulating material, and thermally bonding the coating materials to each other around the heat insulating material or bonding the coating materials with an adhesive.

[ B2. Battery pack ]

The assembled battery of the present embodiment is an assembled battery in which 2 or more battery cells are connected in series or in parallel, and the heat transfer suppressing sheet for an assembled battery of the present embodiment is interposed between the battery cells. Specifically, for example, as shown in fig. 21, the assembled battery B100 is formed by arranging 2 or more battery cells B20 in parallel, connecting them in series or in parallel, and storing them in a battery case B30, and for example, a heat transfer suppressing sheet B40 is interposed between the battery cells B20.

In such a battery pack B100, the heat transfer inhibiting sheet B40 is interposed between the battery cells B20, so that the battery cells B20 can be cooled during normal use.

In addition, in the case where one of the 2 or more battery cells B20 is thermally out of control and has a high temperature, and swelling or ignition occurs, the heat transfer between the battery cells B20 can be suppressed by the presence of the heat transfer suppressing sheet B40 of the present embodiment. Therefore, the occurrence of thermal runaway interlocking can be suppressed, and adverse effects on the battery cell B20 can be suppressed to the minimum.

The various embodiments have been described above with reference to the drawings, but the present application is of course not limited to this example. It is obvious to those skilled in the art that various modifications and corrections can be made within the scope of the claims, and it is understood that these are naturally included in the technical scope of the present application. The components in the above embodiments may be arbitrarily combined within a range not departing from the gist of the present application.

The present application is based on Japanese patent application (Japanese patent application No. 2021-006046) filed on 1 month 18 in 2021 and Japanese patent application (Japanese patent application No. 2021-006047) filed on 1 month 18 in 2021, the contents of which are incorporated herein by reference.

Description of symbols

Heat transfer inhibiting sheet for a10, a50, a60, a70, a80, a90, a95, a110, a120, a130 battery pack

A11, A21, A31, A41, A51, A61 and A71 heat insulating material

A12, A52 coating material

Recesses A13a, A13c, A53a

Protruding part A13b, A53b

A14 void portion

A15 communication port

A20 battery cell

A30 battery case

A100 battery pack

Heat transfer inhibition sheet for B40, B60 and B80 battery pack

B11, B21, B31, B41,71 insulating material

B12, B52, B82 coating material

13a, B13c, B13d recesses

B13B convex part

B14 void portion

B20 battery cell

B30 battery case

B100 battery pack

Claims

1. A heat transfer suppressing sheet for a battery pack, which is used in a battery pack in which 2 or more battery cells are connected in series or parallel, is interposed between the battery cells,

the heat transfer suppression sheet for a battery pack comprises:

a coating material for coating at least a part of the heat insulating material,

a void is formed between the heat insulating material and the coating material.

2. The heat transfer suppressing sheet for a battery pack according to claim 1, wherein at least one of a surface of the heat insulating material facing the coating material and a surface of the coating material facing the heat insulating material has a concave portion and a convex portion.

3. The heat transfer inhibiting sheet for a battery pack according to claim 2, wherein,

the void is formed between the recess and the coating material.

4. The heat transfer suppressing sheet for a battery pack according to claim 3, wherein the convex portion of the heat insulating material is bonded to the coating material.

5. The heat transfer inhibiting sheet for a battery pack according to claim 2, wherein,

the void is formed between the recess and the heat insulating material.

6. The heat transfer suppressing sheet for a battery pack according to claim 5, wherein the convex portion of the coating material is bonded to the heat insulating material.

7. The heat transfer inhibiting sheet for a battery pack according to claim 2, wherein,

8. The heat transfer suppressing sheet for a battery pack according to claim 7, wherein the convex portions of the heat insulating material are bonded to the convex portions of the coating material.

9. The heat transfer control sheet for a battery pack according to any one of claims 2 and 5 to 7, wherein the coating material is composed of an embossed polymer film or a metal plate.

10. The heat transfer inhibiting sheet for a battery pack according to any one of claims 2 to 9, wherein the void portion communicates with the outside of the heat insulating material and the coating material.

11. The heat transfer inhibiting sheet for a battery pack according to any one of claim 2 to 9, wherein,

the void portion is closed at a temperature of less than 60 ℃,

12. The heat transfer control sheet for a battery pack according to claim 11, wherein the heat insulating material and the coating material, or the coating material are bonded to each other by an adhesive that melts at 60 ℃ or higher, and 2 or more adhesives are used as the adhesive, and the 2 or more adhesives have different melting temperatures from each other in the 2 or more regions so as to gradually melt in the 2 or more regions by an increase in temperature.

13. The heat transfer control sheet for a battery pack according to claim 11, wherein the heat insulating material and the coating material, or the coating material are bonded to each other by an adhesive that melts at 60 ℃ or higher, and the adhesive is applied in different amounts to each other in 2 or more regions so as to gradually melt in the 2 or more regions by a rise in temperature.

14. A battery pack in which 2 or more battery cells are connected in series or parallel, wherein the heat transfer suppressing sheet for a battery pack according to any one of claims 2 to 13 is sandwiched between the battery cells.

15. The heat transfer suppressing sheet for a battery pack according to claim 1, wherein the coating material completely coats the heat insulating material.

16. The heat transfer inhibiting sheet for a battery pack according to claim 15, wherein at least one of the inorganic particles and the inorganic fibers contained in the heat insulating material contains a material that releases moisture by heating.

17. The heat transfer inhibiting sheet for a battery pack according to claim 15 or 16, wherein,

The void is formed between the recess and the coating material.

18. The heat transfer inhibiting sheet for a battery pack according to claim 15 or 16, wherein,

the void is formed between the recess and the heat insulating material.

19. The heat transfer inhibiting sheet for a battery pack according to claim 15 or 16, wherein,

the heat insulating material has a concave portion and a convex portion on a surface facing the coating material, and

20. The heat transfer control sheet for a battery pack according to claim 18 or 19, wherein the coating material is composed of an embossed polymer film or a metal plate.

21. A battery pack in which 2 or more battery cells are connected in series or parallel, wherein the heat transfer suppressing sheet for a battery pack according to any one of claims 15 to 20 is sandwiched between the battery cells.