Battery pack

Abstract

This invention provides a battery pack capable of preventing a chain reaction of thermal runaway caused by high-temperature gases from abnormal battery cells during thermal runaway. The battery pack of this invention comprises: a module having a plurality of battery cells each equipped with a safety valve; a housing housing the module; and a thermal insulation material disposed between the module and the housing. The thermal insulation material comprises a first thermal insulation sheet and a second thermal insulation sheet laminated thereon, the thermal insulation material being arranged such that the first thermal insulation sheet is located on the module side and the second thermal insulation sheet is located on the housing side. A plurality of openings are formed in the second thermal insulation sheet, and a cover sheet covering at least a portion of each opening is disposed thereon. The cover sheet is bonded to the first thermal insulation sheet and / or the second thermal insulation sheet by an adhesive layer. When the second thermal insulation sheet is viewed from above, one of the openings overlaps with at least a portion of one of the safety valves.

Description

Technical Field

[0001] This invention relates to battery packs. Background Technology

[0002] In battery packs containing multiple battery cells housed in a casing, high-temperature gases and flames can sometimes be generated during thermal runaway. These gases and flames can spread to the surrounding area, potentially inducing further thermal runaway.

[0003] To prevent the chain reaction of thermal runaway and to release the high-temperature gas generated during thermal runaway, safety valves have always been installed in the module.

[0004] In addition, if the high-temperature gas released from the safety valve comes into direct contact with the casing, the temperature of the casing will rise, sometimes causing a thermal effect around the battery pack.

[0005] In order to prevent high-temperature gas from coming into direct contact with the casing, thermal insulation material was previously placed between the module and the casing.

[0006] As such a battery pack, Patent Document 1 discloses an energy storage device comprising: an energy storage stack including a plurality of energy storage units, each having an exhaust valve on its upper surface; an upper housing covering the energy storage stack from above; and a first heat-resistant sheet and a second heat-resistant sheet having heat resistance relative to exhaust gas discharged from the exhaust valves and disposed between the upper housing and the energy storage stack. The first heat-resistant sheet has a plurality of holes at a position where it overlaps with each of the exhaust valves in the vertical direction, and the second heat-resistant sheet is disposed above the first heat-resistant sheet in such a way as to cover the plurality of holes.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2023-59480 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] In the energy storage device (battery pack) described in Patent Document 1, during thermal runaway, high-temperature gas discharged from the discharge valve of the abnormal battery cell blows through the holes of the first heat-resistant sheet towards the second heat-resistant sheet. This pushes the second heat-resistant sheet upwards, separating it from the first heat-resistant sheet, thus forming a gas flow path between the two sheets. Because the gas is blocked by the second heat-resistant sheet, it does not reach the upper casing, preventing damage to the upper casing. Furthermore, the first heat-resistant sheet prevents the gas intercepted by the second heat-resistant sheet from contacting adjacent cells, thus suppressing temperature rise in adjacent cells.

[0012] However, in the energy storage device (battery pack) described in Patent Document 1, because the high-temperature gas is blocked by the second heat-resistant sheet, the high-temperature gas may flow back through other holes in the first heat-resistant sheet from the discharge valve of the normal battery cell adjacent to the abnormal battery cell. In the event of high-temperature gas backflow, the normal cell may experience thermal runaway.

[0013] That is, in the energy storage device (battery pack) described in Patent Document 1, there is a problem that thermal runaway cannot be adequately prevented.

[0014] This invention was made to solve the above-mentioned problems. The purpose of this invention is to provide a battery pack that can prevent the chain reaction of thermal runaway caused by high-temperature gas from abnormal battery cells during thermal runaway.

[0015] Methods for solving problems

[0016] The battery pack of the present invention comprises: a module having a plurality of battery cells each having a safety valve; a housing for housing the module; and a heat-insulating material disposed between the module and the housing, characterized in that the heat-insulating material comprises a first heat-insulating sheet and a second heat-insulating sheet laminated thereon, the heat-insulating material being arranged such that the first heat-insulating sheet is located on the module side and the second heat-insulating sheet is located on the housing side, a plurality of openings are formed in the second heat-insulating sheet, and a cover sheet covering at least a portion of each of the plurality of openings is disposed thereon, the cover sheet being bonded to the first heat-insulating sheet and / or the second heat-insulating sheet by an adhesive layer, and when the second heat-insulating sheet is viewed from top perspective, one of the openings is located at a position overlapping at least a portion of one of the safety valves.

[0017] In the battery pack of the present invention, it is possible to prevent the chain reaction of thermal runaway caused by high-temperature gases from abnormal battery cells generated during thermal runaway. The principle is explained below.

[0018] In the battery pack of this invention, a safety valve is provided in each module. Therefore, when a high-temperature gas is generated due to thermal runaway of the battery cell, the gas is discharged from the safety valve. Then, the gas released from the safety valve reaches the heat insulation material.

[0019] The thermal insulation material includes a first thermal insulation sheet and a second thermal insulation sheet laminated on the first thermal insulation sheet.

[0020] Furthermore, the thermal insulation material is configured such that the first thermal insulation sheet is located on the module side and the second thermal insulation sheet is located on the shell side.

[0021] Therefore, the gas that reaches the insulation material first comes into contact with the first insulation sheet.

[0022] Gas passes through the passage formed by the melting of the first insulation sheet and the gaps formed in the first insulation sheet.

[0023] An opening is formed in the second insulation sheet, and when the second insulation sheet is viewed from above, the opening is located at a position that overlaps with at least a portion of the safety valve.

[0024] Therefore, the gas that has passed through the first insulation sheet reaches the vicinity of the opening of the second insulation sheet.

[0025] A cover sheet is provided at the opening to cover at least a portion of the opening, and the cover sheet is bonded to the first insulation sheet and / or the second insulation sheet by an adhesive layer.

[0026] The gas reaching the vicinity of the opening in the second insulation sheet is at a high temperature, thus thermally decomposing the adhesive layer of the cover sheet. Consequently, the adhesion between the cover sheet and the first and / or second insulation sheets weakens.

[0027] Additionally, air pressure is applied to the cover sheet from the module side toward the housing side.

[0028] As a result, the cover sheet peels off from the first insulation sheet and / or the second insulation sheet.

[0029] Then, the gas that has passed through the first insulation sheet is released between the insulation material and the shell through the opening of the second insulation sheet.

[0030] Under these conditions, the temperature of the high-temperature gas decreases as it passes through the first insulating sheet, and the gas pressure also decreases. Therefore, even if the gas is released from the opening and comes into contact with the casing, the casing is not easily heated by the gas, and it is also less likely to be damaged.

[0031] In addition, the gas released from the opening of the second insulation sheet diffuses between the insulation material and the shell, and also reaches other openings of the second insulation sheet.

[0032] However, since a cover sheet is provided inside the other openings of the second insulation sheet, even if gas reaches the other openings of the second insulation sheet, it can prevent gas from flowing back from the other openings of the second insulation sheet to the module side.

[0033] Based on this principle, this invention prevents high-temperature gases generated from abnormal battery cells during thermal runaway from reaching other battery cells. This prevents a cascading effect of thermal runaway.

[0034] In the battery pack of the present invention, it is preferable that at least one of the cover sheets is disposed inside each of the plurality of openings, and it is preferable that a plurality of the cover sheets are disposed inside the openings.

[0035] If the cover sheet is positioned inside the opening, the cover sheet can be easily peeled off from the first insulation sheet and / or the second insulation sheet.

[0036] In the battery pack of the present invention, it is preferable that a plurality of the cover sheets are disposed inside each of the plurality of openings.

[0037] To prevent the backflow of high-temperature gas from the housing side, it is preferable that there is no gap between the opening and the cover plate.

[0038] When the cover sheet is arranged inside the opening without creating a gap between the opening and the cover sheet, the size of each cover sheet becomes smaller when multiple cover sheets are arranged compared to arranging a one-piece cover sheet.

[0039] When an integral cover is placed at the opening, if the integral cover peels off due to gas from the module side, the integral cover, being large, may sometimes block the gas flow path and hinder gas diffusion.

[0040] On the other hand, when multiple covers are arranged at the opening, when the multiple covers are stripped by gas from the module side, one cover is smaller, so each cover does not easily obstruct the diffusion of gas.

[0041] In the battery pack of the present invention, preferably at least a portion of the plurality of cover sheets are arranged in contact with each other.

[0042] Furthermore, in the battery pack of the present invention, it is preferable that the cover sheet is configured such that at least a portion of it contacts the contour of the opening.

[0043] If the cover is configured in this way, it is easy to prevent gas from flowing back through the gaps between the cover sheets and the gap between the cover sheets and the opening.

[0044] In the battery pack of the present invention, it is preferable that the cover sheet is configured to cover the outline of the opening from the housing side.

[0045] If the cover is configured in this way, no gap will be generated between the cover and the opening, which easily prevents gas from flowing back between the cover and the opening.

[0046] In the battery pack of the present invention, it is preferable that the first heat insulation sheet has a cut-out portion that extends from the main surface on which the second heat insulation sheet is stacked to another main surface, and when the heat insulation material is viewed from the side of the second heat insulation sheet, at least a portion of the cut-out portion is located inside the opening portion.

[0047] If a slit is formed in the first insulation sheet, high-temperature gas from the module side can easily reach the cover sheet through the slit.

[0048] In the battery pack of the present invention, the cut portion may be formed as a line when the heat insulation material is viewed from the second heat insulation sheet side.

[0049] Linear cuts can be easily formed using tools or similar means.

[0050] In the battery pack of the present invention, when the heat insulation material is viewed from above from the side of the second heat insulation sheet, the cut portion is formed to intersect the contour of the opening portion.

[0051] Furthermore, in the battery pack of the present invention, it is preferable that a plurality of the cutouts are formed in the first heat-insulating sheet.

[0052] Furthermore, in the battery pack of the present invention, it is preferable that, when the heat insulation material is viewed from the second heat insulation sheet side, a plurality of linear cutouts are formed in the first heat insulation sheet, and at least a portion of the plurality of cutouts are in contact with each other.

[0053] If the cut is formed in this way, high-temperature gas from the module side can easily pass through the first insulation sheet.

[0054] In the battery pack of the present invention, it is preferable that a plurality of the cover sheets are disposed inside the opening, at least a portion of the plurality of cover sheets are in contact with each other, and when the heat insulation material is viewed from the second heat insulation sheet side, the cut is formed along the portion of the cover sheets that are in contact with each other.

[0055] Such a cover and cut-out portion can be formed by simultaneously punching the integral cover and the first insulation sheet.

[0056] In the battery pack of the present invention, it is preferable that when the heat insulation material is viewed from the second heat insulation sheet side, the portions of the cover sheets that are in contact with each other are formed in a straight line.

[0057] Such a cover and cut-out section can be formed by simultaneously punching the integral cover and the first insulation sheet into a straight line.

[0058] In the battery pack of the present invention, the top view shape of the opening is preferably selected from at least one shape chosen from the group consisting of triangles, quadrilaterals, hexagons, circles, ellipses and racetrack shapes.

[0059] This type of opening can be easily formed.

[0060] In the battery pack of the present invention, the first heat insulation sheet is preferably an inorganic fiber pad.

[0061] Inorganic fiber mats can be easily molded, and they exhibit excellent performance as the primary thermal insulation material.

[0062] In the battery pack of the present invention, the inorganic fiber pad is preferably made by processing inorganic fibers containing at least one type of fiber selected from silica fiber, glass fiber, alumina fiber, aluminosilicate fiber, basalt fiber, rock wool, and biosoluble fiber into a pad shape.

[0063] Inorganic fiber mats made of such materials can be easily processed.

[0064] In the battery pack of the present invention, the inorganic fiber pad may be formed by processing inorganic fibers containing fibers with a melting point of 1000°C or higher into a pad shape.

[0065] When inorganic fiber pads contain fibers with a melting point above 1000℃, the inorganic fibers have high heat resistance, so even if high-temperature gases from abnormal battery cells reach the inorganic fiber pads, the inorganic fiber pads are not easily degraded.

[0066] In the battery pack of the present invention, the inorganic fiber pad may be formed by processing inorganic fibers containing fibers with a melting point of less than 1000°C into a pad shape.

[0067] When the inorganic fiber pad contains fibers with a melting point of less than 1000°C, the inorganic fiber pad melts and easily forms a gas flow path when high-temperature gas from the abnormal battery cell reaches the inorganic fiber pad.

[0068] In the battery pack of the present invention, the second heat-insulating sheet can be a mica sheet or a heat-resistant resin sheet.

[0069] These materials are suitable as a second insulation sheet.

[0070] In the battery pack of the present invention, it is preferable that the cover sheet is made of the same material as the second heat-insulating sheet.

[0071] By punching out an integral sheet in a way that forms an opening, it is possible to simultaneously produce a second insulation sheet and a cover sheet.

[0072] In the battery pack of the present invention, the adhesive layer preferably comprises an organic adhesive layer.

[0073] If the adhesive layer contains an organic adhesive layer, it is prone to thermal decomposition when high-temperature gas from the abnormal battery cell reaches the cover sheet through the inorganic fiber pad.

[0074] Therefore, the cover sheet can be easily peeled off from the inorganic fiber pad.

[0075] In the battery pack of the present invention, the heat insulation material may further include a third heat insulation sheet, which is laminated on the second heat insulation sheet in such a way that it covers the opening from the housing side.

[0076] Such a battery pack is configured such that the first heat insulation sheet is located on the lower side in the vertical direction and the third heat insulation sheet is located on the upper side in the vertical direction.

[0077] In this battery pack configuration, the safety valve is located vertically upwards, so the high-temperature gas from the abnormal battery cell is released vertically upwards.

[0078] Then, the gas reaches the third insulation sheet through the opening formed in the second insulation sheet.

[0079] The gas is blocked by a third insulating sheet. As a result, the gas is prevented from coming into contact with the casing.

[0080] Furthermore, the third insulation sheet is pushed upwards by the gas, moving away from the second insulation sheet. As a result, the gas diffuses through the gap formed between the third and second insulation sheets. Moreover, the temperature and pressure of the gas decrease.

[0081] In the battery package of the present invention, the housing may have a receiving portion consisting of a bottom and a side wall portion and a cover portion covering the receiving portion, and the safety valve may be configured to be located on the bottom side or on the cover side.

[0082] When configuring the battery pack of the present invention, from the viewpoint of failure protection, the battery pack is sometimes configured such that the safety valve is located on the upper or lower side of the vertical direction.

[0083] Battery packs are mostly configured with the bottom of the casing or the cover located on the lower side. Therefore, if the safety valve is configured with the bottom or cover located on the lower side of the casing, it is easy for the safety valve to be located on the upper or lower side in the vertical direction.

[0084] Invention Effects

[0085] According to the present invention, a battery pack is provided that can prevent a chain reaction of thermal runaway caused by high-temperature gases from abnormal battery cells generated during thermal runaway. Attached Figure Description

[0086] Figure 1A This is a perspective view schematically illustrating an example of a battery pack according to a first embodiment of the present invention.

[0087] Figure 1B It is along Figure 1A A cross-sectional view along line AA.

[0088] Figure 1C yes Figure 1A The diagram shown is an exploded view of the battery pack.

[0089] Figure 2A This is a schematic cross-sectional view illustrating a safety valve of a battery pack according to a first embodiment of the present invention and an example of its vicinity.

[0090] Figure 2B Viewed from the insulation material side Figure 2A The safety valve shown is shown in top view.

[0091] Figure 3A The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the first embodiment of the present invention.

[0092] Figure 3B The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the first embodiment of the present invention.

[0093] Figure 3C The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the first embodiment of the present invention.

[0094] Figure 4A This is a top view schematically illustrating an example of another shape of mica sheet in a battery pack according to a first embodiment of the present invention.

[0095] Figure 4B This is a top view schematically illustrating an example of another shape of mica sheet in a battery pack according to a first embodiment of the present invention.

[0096] Figure 4C This is a top view schematically illustrating an example of another shape of mica sheet in a battery pack according to a first embodiment of the present invention.

[0097] Figure 4D This is a top view schematically illustrating an example of another shape of mica sheet in a battery pack according to a first embodiment of the present invention.

[0098] Figure 4E This is a top view schematically illustrating an example of another shape of mica sheet in a battery pack according to a first embodiment of the present invention.

[0099] Figure 5A This is an enlarged cross-sectional view schematically showing an example of the cross-section of the heat-insulating material of the battery pack according to the second embodiment of the present invention.

[0100] Figure 5B yes Figure 5A A top view of an example of mica sheets contained in the insulation material shown.

[0101] Figure 5C yes Figure 5A A top view of an example of an inorganic fiber pad contained in the insulation material shown.

[0102] Figure 6A This is a top view schematically showing another example of the cut portion of the inorganic fiber pad formed in the battery pack of the second embodiment of the present invention.

[0103] Figure 6B This is a top view schematically showing the opening of the mica sheet formed in the battery pack of the second embodiment of the present invention and another example of the mica sheet.

[0104] Figure 7A This is a top view schematically showing another example of the cut portion of the inorganic fiber pad formed in the battery pack of the second embodiment of the present invention.

[0105] Figure 7B This is a top view schematically showing the opening of the mica sheet formed in the battery pack of the second embodiment of the present invention and another example of the mica sheet.

[0106] Figure 8A This is a top view schematically showing another example of the cut portion of the inorganic fiber pad formed in the battery pack of the second embodiment of the present invention.

[0107] Figure 8B This is a top view schematically showing the opening of the mica sheet formed in the battery pack of the second embodiment of the present invention and another example of the mica sheet.

[0108] Figure 9A This is an enlarged cross-sectional view schematically showing an example of the cross-section of the heat-insulating material of the battery pack according to the third embodiment of the present invention.

[0109] Figure 9B This is an enlarged cross-sectional view schematically showing another example of the cross-section of the heat-insulating material of the battery pack according to the third embodiment of the present invention.

[0110] Figure 9C This is an enlarged cross-sectional view schematically showing another example of the cross-section of the heat-insulating material of the battery pack according to the third embodiment of the present invention.

[0111] Figure 10 This is an enlarged cross-sectional view schematically illustrating an example of a battery pack according to a fourth embodiment of the present invention.

[0112] Figure 11A The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the fourth embodiment of the present invention.

[0113] Figure 11B The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the fourth embodiment of the present invention.

[0114] Figure 11C The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the fourth embodiment of the present invention.

[0115] Figure 12 This is a photograph of the thermal insulation material of Embodiment 1-1 of the present invention, viewed from the mica sheet side.

[0116] Figure 13 These are photographs of the thermal insulation materials of Embodiments 1-2 of the present invention, viewed from the mica sheet side.

[0117] Figure 14 This is a schematic diagram illustrating the gas pressure cracking test 1.

[0118] Figure 15A This is a photograph taken from the second clamp side before the air valve is opened during a gas pressure cracking test using the thermal insulation material of Example 1-1.

[0119] Figure 15B This is a photograph taken from the second clamp side after the air valve is opened during a gas pressure cracking test using the thermal insulation material of Example 1-1.

[0120] Figure 16A This is a photograph taken from the second clamp side before the air valve is opened during a gas pressure cracking test using the thermal insulation material of Examples 1-2.

[0121] Figure 16B This is a photograph taken from the second clamp side after the air valve is opened during a gas pressure cracking test using the thermal insulation material of Examples 1-2.

[0122] Figure 17A This is a schematic top view of the inorganic fiber mat of Example 2-1.

[0123] Figure 17B This is a schematic top view of the opening of the mica sheet in Embodiment 2-1.

[0124] Figure 18A This is a schematic top view showing the cut portion of the inorganic fiber pad of Example 2-2.

[0125] Figure 18B This is a schematic top view of the opening of the mica sheet in Embodiment 2-2.

[0126] Figure 19AThis is a schematic top view showing the cut portion of the inorganic fiber pad of Examples 2-3.

[0127] Figure 19B The diagram schematically shows the opening of the mica sheet in Examples 2-3 and a top view of the mica sheet.

[0128] Figure 20A This is a schematic top view of the inorganic fiber pad of Comparative Example 2-1.

[0129] Figure 20B This is a schematic top view of the mica sheet of Comparative Example 2-1.

[0130] Figure 21 This is a schematic diagram illustrating the cracking test 2. Detailed Implementation

[0131] The battery pack of the present invention will now be described in detail. However, the present invention is not limited to the following structure, and can be appropriately modified and applied without changing the spirit of the invention. It should be noted that the present invention also includes combinations of two or more of the preferred configurations of the present invention described below.

[0132] (First Implementation)

[0133] For the battery pack of the first embodiment of the present invention, the case in which the first heat-insulating sheet, the second heat-insulating sheet and the cover sheet constituting the heat-insulating material are inorganic fiber pads, mica sheets and mica sheets will be described.

[0134] Figure 1A This is a perspective view schematically illustrating an example of a battery pack according to a first embodiment of the present invention.

[0135] Figure 1B It is along Figure 1A A cross-sectional view along line AA.

[0136] Figure 1C yes Figure 1A The diagram shown is an exploded view of the battery pack.

[0137] Figure 1A , Figure 1B and Figure 1C The battery pack 10 shown includes a module 20 having multiple battery cells 21 and a housing 30 for storing the module 20.

[0138] like Figure 1B As shown, in the battery pack 10, a safety valve 22 is provided in each battery cell 21.

[0139] like Figure 1BAs shown, the housing 30 has a storage section 31 consisting of a bottom 31b and a side wall 31s, and a cover 32 covering the storage section 31, in which the module 20 is stored.

[0140] In addition, in the battery pack 10, a heat insulation material 40 is provided between the module 20 and the housing 30.

[0141] The battery cell 21 stores electricity, and is preferably a rechargeable secondary battery. Examples of secondary batteries include lithium-ion batteries, nickel-metal hydride batteries, and sodium-ion batteries.

[0142] Figure 1B as well as Figure 1C The battery cell 21 shown is rectangular parallelepiped. However, in the battery pack of the present invention, the battery cell may also be a three-dimensional shape other than a rectangular parallelepiped (e.g., a cube or deformed shape).

[0143] like Figure 1B as well as Figure 1C As shown, in module 20, multiple battery cells 21 are arranged in a row and fixed by connecting module component 20a.

[0144] In addition, such as Figure 1C As shown, the battery cell 21 has a terminal 23, and adjacent battery cells 21 are electrically connected by a busbar 20b disposed on the connection module component 20a through each terminal 23.

[0145] Busbar 20b is a flat, conductive metal component. Examples of materials that can be used for busbar 20b include copper, copper alloys, stainless steel (SUS), and aluminum.

[0146] Busbar 20b can also be fixed to terminal 23 by any fixing means (such as thread fastening, welding, etc.).

[0147] Materials that make up the shell 30 include steel, aluminum, etc. As steel, stainless steel (SUS) is preferred.

[0148] Figure 2A This is a schematic cross-sectional view illustrating a safety valve of a battery pack according to a first embodiment of the present invention and an example of its vicinity.

[0149] Figure 2B Viewed from the insulation material side Figure 2A The safety valve shown is shown in top view.

[0150] like Figure 2A As shown, the thermal insulation material 40 includes an inorganic fiber pad 41 as a first thermal insulation sheet and a mica sheet 42 as a second thermal insulation sheet, which is laminated on the inorganic fiber pad 41.

[0151] The thermal insulation material 40 is configured such that the inorganic fiber pad 41 is located on the module 20 side and the mica sheet 42 is located on the shell 30 side.

[0152] like Figure 2A As shown, an opening 42a is formed in the mica sheet 42, penetrating the mica sheet 42, as... Figure 2B As shown, four mica sheets 50 serving as cover sheets are arranged inside the opening 42a.

[0153] The mica sheet 50 is bonded to the inorganic fiber pad 41 via an adhesive layer (not shown).

[0154] In addition, such as Figure 2B As shown, when the mica sheet 42 is viewed from above, an opening 42a is located at a position that overlaps with a safety valve 22.

[0155] And, as Figure 2B As shown, the opening 42a is circular. Additionally, the four mica sheets 50 are congruent sectors, which combine to form a circle.

[0156] The four mica sheets 50 are in contact with the outline of the opening 42a and form a circle by contacting each other.

[0157] In battery pack 10, a cascading thermal runaway mechanism can be established to prevent thermal runaway caused by high-temperature gases from abnormal battery cells. The principle behind this mechanism is explained below.

[0158] Figures 3A-3C The diagram illustrates the principle of the chain reaction that prevents thermal runaway in the event of thermal runaway in a battery cell in the battery pack of the first embodiment of the present invention.

[0159] like Figure 3A As shown, when a battery cell 21a experiences thermal runaway and generates high-temperature gas from the battery cell 21a, gas G is discharged from safety valve 22a (in... Figure 3A In the diagram, the symbol "G" represents gas, and an arrow indicates the direction of gas flow.

[0160] Then, the gas released from safety valve 22a reaches the insulation material 40.

[0161] The thermal insulation material 40 includes an inorganic fiber pad 41 and a mica sheet 42 laminated on the inorganic fiber pad 41.

[0162] Furthermore, the thermal insulation material 40 is configured such that the inorganic fiber pad 41 is located on the module 20 side and the mica sheet 42 is located on the housing 30 side.

[0163] Therefore, the gas G that reaches the insulation material 40 first comes into contact with the inorganic fiber pad 41.

[0164] The inorganic fiber pad 41 is not dense, and there are spaces between the inorganic fibers, so gas G can pass through the inorganic fiber pad 41.

[0165] An opening 42a is formed in the mica sheet 42, and when the mica sheet 42 is viewed from above, the opening 42a is located at a position that overlaps with the safety valve 22.

[0166] Therefore, the gas G passing through the inorganic fiber pad 41 reaches the vicinity of the opening 42a of the mica sheet 42.

[0167] A mica sheet 50 is disposed inside the opening 42a of the mica sheet 42, and the mica sheet 50 is bonded to the inorganic fiber pad 41 by an adhesive layer (not shown).

[0168] The gas G reaching the vicinity of the opening 42a of the mica sheet 42 is at a high temperature, thus causing thermal decomposition of the adhesive layer bonding the mica sheet 50. As a result, the adhesion between the mica sheet 50 and the inorganic fiber pad 41 weakens.

[0169] In addition, air pressure is applied to the mica sheet 50 from the module 20 side toward the housing 30 side.

[0170] The result, such as Figure 3B As shown, mica sheet 50 is peeled off from inorganic fiber pad 41.

[0171] Then, the gas G that has passed through the inorganic fiber pad 41 is released between the heat insulation material 40 and the shell 30 through the opening 42a of the mica sheet 42.

[0172] Under these conditions, the high-temperature gas G cools down as it passes through the inorganic fiber pad 41, and its pressure also decreases. Therefore, even if the gas G is released from the opening 42a and comes into contact with the casing 30, the casing 30 is not easily heated by the gas G, and it is also less likely to be damaged.

[0173] In addition, gas G is released from the opening 42a of the mica sheet 42, thus preventing backflow from other safety valves 22 through the interior of the inorganic fiber pad 41.

[0174] In addition, such as Figure 3C As shown, the gas G released from the opening 42a of the mica sheet 42 diffuses between the heat insulation material 40 and the shell 30, and also reaches other openings 42a of the mica sheet 42.

[0175] However, since mica sheets 50 are disposed inside the other openings 42a of the mica sheet 42, even if gas G reaches the other openings 42a of the mica sheet 42, it is possible to prevent backflow from the other openings 42a of the mica sheet 42 to the module 20 side.

[0176] Based on this principle, in the battery pack 10, it is possible to prevent the high-temperature gas G generated from the abnormal battery cell 21a during thermal runaway from reaching other battery cells 21. Thus, it is possible to prevent the chain reaction of thermal runaway.

[0177] Hereinafter, a preferred embodiment of the heat-insulating material of the battery pack according to the first embodiment of the present invention will be described.

[0178] (Inorganic fiber mat)

[0179] The thickness of the inorganic fiber pad 41 is preferably 0.5 mm to 10 mm, and more preferably 1 mm to 4 mm.

[0180] If the inorganic fiber pad is less than 0.5 mm thick, it is too thin, and therefore the gas temperature and pressure do not easily decrease when the gas passes through it. As a result, the gas violently reaches the shell at a high temperature, making the shell prone to deterioration.

[0181] If the thickness of the inorganic fiber pad exceeds 10mm, the inorganic fiber pad becomes too thick, making it difficult to miniaturize the battery pack as a whole.

[0182] The bulk density of the inorganic fiber pad 41 is preferably 0.1 g / cm³. 3 ~1.0g / cm 3 More preferably 0.2 g / cm³ 3 ~0.7g / cm 3 .

[0183] The bulk density of the inorganic fiber pad 41 is less than 0.1 g / cm³. 3 In this situation, the gaps between the inorganic fibers increase, making it difficult for the gas temperature and pressure to decrease as it passes through the inorganic fiber pad. As a result, the gas violently reaches the shell at a high temperature, causing the shell to deteriorate easily.

[0184] The bulk density of the inorganic fiber pad 41 exceeds 1.0 g / cm³. 3 In such cases, gas has difficulty passing through the inorganic fiber pad, and the high-temperature gas remains inside the battery cell, making it difficult to lower the temperature inside the battery cell. Therefore, a chain reaction of thermal runaway can easily occur.

[0185] The inorganic fiber mat 41 is preferably made by processing inorganic fibers, including at least one type of fiber selected from silica fiber, glass fiber, alumina fiber, aluminosilicate fiber, basalt fiber, rock wool, and biosoluble fiber, into a mat shape.

[0186] Inorganic fiber mats made of such materials can be easily processed.

[0187] Inorganic fiber mat 41 can also be made by processing inorganic fibers containing fibers with a melting point of 1000°C or higher into a mat shape. Examples of such inorganic fibers include silica fibers, alumina fibers, aluminosilicate fibers, and biosoluble fibers.

[0188] When inorganic fiber pads contain fibers with a melting point above 1000℃, the inorganic fibers have high heat resistance, so even if high-temperature gases from abnormal battery cells reach the inorganic fiber pads, the inorganic fiber pads are not easily degraded.

[0189] Inorganic fiber mat 41 can also be made by processing inorganic fibers containing fibers with a melting point of less than 1000°C into a mat shape. Examples of such inorganic fibers include glass fiber, basalt fiber, and rock wool.

[0190] When the inorganic fiber pad contains fibers with a melting point of less than 1000°C, the inorganic fiber pad melts and easily forms a gas flow path when high-temperature gas from the abnormal battery cell reaches the inorganic fiber pad.

[0191] (Mica sheet)

[0192] The thickness of the mica sheet 42 is preferably 0.05mm to 2.0mm, more preferably 0.1mm to 1.0mm, and even more preferably 0.1mm to 0.5mm.

[0193] If the thickness of the mica sheet is less than 0.05mm, the strength of the mica sheet will be lower and it will be easily damaged.

[0194] If the thickness of the mica sheet exceeds 2.0 mm, the mica sheet becomes too thick, making it difficult to miniaturize the battery pack as a whole.

[0195] In the above Figure 2B In the present invention, the top view shape of the opening 42a formed in the mica sheet 42 is circular. However, in the battery pack of the first embodiment of the present invention, the top view shape of the opening formed in the mica sheet can also be triangular, quadrilateral, hexagonal, elliptical, racetrack, or other shapes.

[0196] This type of opening can be easily formed.

[0197] The area of ​​the top view of the opening 42a is preferably 1.0 cm². 2 ~18cm 2 More preferably 3cm 2 ~12cm 2 .

[0198] If the area of ​​the top view of the opening is less than 1.0 cm² 2 If so, the gas will have difficulty passing through the opening.

[0199] If the top view area of ​​the opening exceeds 18cm² 2 The opening tends to widen compared to the area of ​​the mica sheet where the gas reaches. Mica sheets positioned inside the opening peel off from the inorganic fiber pad due to gas penetration, making it difficult for mica sheets positioned in areas where the gas does not reach to peel off, as will be discussed later.

[0200] In the battery pack 10, when the mica sheet 42 is viewed from above, an opening may be located at a position that overlaps with at least a portion of a safety valve, but preferably an opening is located inside the outline of a safety valve.

[0201] If the opening is located in such a position, the gas released from the safety valve can easily reach the opening.

[0202] (Mica sheet)

[0203] In the above Figure 2B In the heat insulation material 40 shown, each mica sheet 50 is in contact, and each mica sheet 50 is arranged in such a way that it is in contact with the contour of the opening 42a.

[0204] That is, the opening 42a is completely covered by the mica sheet 50 without gaps.

[0205] Therefore, in the battery pack 10, the backflow of high-temperature gas G from the casing 30 side can be prevented.

[0206] In the above Figure 2B In the heat insulation material 40 shown, four mica sheets 50 are disposed inside an opening 42a.

[0207] When the mica sheet 50 is arranged inside the opening 42a without creating a gap between the opening 42a and the mica sheet 50, the size of each mica sheet becomes smaller when multiple mica sheets are arranged compared to arranging a single piece (monolithic) mica sheet.

[0208] When the mica sheet is arranged as a whole (integrated) piece in the opening 42a, if the mica sheet is peeled off due to gas G from the module 20 side, the mica sheet will be large. Therefore, the mica sheet may sometimes block the flow path of gas G and hinder the diffusion of gas.

[0209] On the other hand, if multiple mica sheets 50 are arranged in the opening 42a, and the multiple mica sheets 50 are peeled off due to gas G from the module 20 side, then each mica sheet 50 is small, and therefore each mica sheet 50 is difficult to obstruct the diffusion of gas G.

[0210] As mentioned above, in Figure 2BIn the heat insulation material 40 shown, a mica sheet 50 is disposed without gaps in an opening 42a.

[0211] However, in the battery pack of the first embodiment of the present invention, there may be a gap between an opening and a mica sheet disposed inside it, or there may be a gap between the mica sheets themselves.

[0212] Alternatively, in the battery pack of the first embodiment of the present invention, a single piece (integral) of mica sheet may be disposed in an opening.

[0213] With this structure, the number of mica sheets in the overall battery pack is reduced, enabling efficient battery pack manufacturing.

[0214] Next, the shape of the mica sheet will be described when multiple mica sheets are arranged inside the opening.

[0215] Figures 4A-4E This is a top view schematically illustrating an example of another shape of mica sheet in a battery pack according to a first embodiment of the present invention.

[0216] like Figure 4A As shown, the mica sheet in the battery pack of the first embodiment of the present invention can be two mica sheets 50a.

[0217] Mica sheet 50a is semi-circular. If two mica sheets 50a are combined, they will form a circular shape.

[0218] like Figure 4B As shown, the mica sheet in the battery pack of the first embodiment of the present invention can be four mica sheets 50b1, 50b2, 50b3 and 50b4.

[0219] Mica sheets 50b1, 50b2, 50b3, and 50b4 are arranged in a circular shape from left to right. That is, mica sheets 50b1, 50b2, 50b3, and 50b4 are arranged in a shape that divides the circle into four equal parts by a straight line perpendicular to the horizontal direction.

[0220] like Figure 4C As shown, the mica sheet in the battery pack of the first embodiment of the present invention can be two mica sheets 50c1 and 50c2.

[0221] Mica sheet 50c1 is a ring shape, and mica sheet 50c2 is a circle located inside mica sheet 50c1.

[0222] like Figure 4D As shown, the mica sheet in the battery pack of the first embodiment of the present invention can be four mica sheets 50d.

[0223] Each mica sheet (50d) is a right-angled isosceles triangle, which together form a square shape.

[0224] like Figure 4E As shown, the mica sheet in the battery pack of the first embodiment of the present invention can be four mica sheets 50e.

[0225] The mica sheet 50e is a congruent rectangle, which forms a square shape when arranged sequentially from left to right.

[0226] That is, each mica sheet 50e is a shape that divides the square into four equal parts by a straight line perpendicular to the horizontal direction.

[0227] In the thermal insulation material 40, the mica sheet 50 is bonded to the inorganic fiber pad 41 through an adhesive layer (not shown).

[0228] As an adhesive layer, it is preferable to include a material that undergoes thermal decomposition upon arrival of the gas.

[0229] If the adhesive layer contains such a material, the mica sheet 50 will be easily peeled off when the gas reaches it.

[0230] It should be noted that materials that undergo thermal decomposition upon the arrival of gas are, for example, organic materials with a thermal decomposition temperature above 80°C. More specifically, polyamide-based organic materials can be cited as an example.

[0231] If the adhesive layer (not shown) contains a polyamide-based organic material, the adhesive layer is prone to thermal decomposition when the high-temperature gas G from the abnormal battery cell passes through the inorganic fiber pad 41 and reaches the mica sheet 50.

[0232] Therefore, the mica sheet 50 can be easily peeled off from the inorganic fiber pad 41.

[0233] In addition, in the thermal insulation material 40, the mica sheet 42 can also be bonded to the inorganic fiber pad 41 through an adhesive layer.

[0234] Alternatively, in the insulation material 40, the mica sheet 50 may not be bonded to the inorganic fiber pad 41, but rather bonded to the inner wall of the opening 42a of the mica sheet 42 via an adhesive layer. Furthermore, the mica sheet 50 may also be bonded to both the inorganic fiber pad 41 and the inner wall of the opening 42a of the mica sheet 42 via an adhesive layer.

[0235] In addition, when multiple mica sheets 50 are configured, the mica sheets can also be bonded to each other through an adhesive layer.

[0236] In the battery pack 10, the mica sheet 42, which serves as the second heat insulation sheet, and the mica sheet 50, which serves as the cover sheet, are both made of the same mica material. As will be described in detail later, such mica sheet 42 and mica sheet 50 can be manufactured simultaneously by punching an integral mica sheet in a manner that forms an opening.

[0237] In addition, in the battery pack of the present invention, the cover sheet may be made of the same material as the second heat insulation sheet, or it may be made of a different material.

[0238] A method for manufacturing the heat-insulating material contained in the battery pack according to the first embodiment of the present invention will be described.

[0239] In the manufacture of this insulation material, inorganic fiber pads and mica sheets are prepared.

[0240] Next, the mica sheet is punched to produce a mica sheet with an opening and a mica sheet.

[0241] Next, an adhesive layer is used to bond the mica sheet with the opening to the main surface of the inorganic fiber mat. Additionally, the mica sheet is bonded to the main surface of the inorganic fiber mat using an adhesive layer, with the mica sheet being tucked inside the opening.

[0242] Therefore, it is possible to manufacture heat-insulating materials for the battery packs configured in this invention.

[0243] When multiple mica sheets are used, they can be cut and divided with a knife or similar tool before bonding them.

[0244] Alternatively, slits can be pre-formed on the mica sheet, and the mica sheet can be punched in a manner that includes the slits, thereby forming multiple mica sheets.

[0245] At this point, the mica sheet can be punched by intersecting the outline of the cut portion formed on the mica sheet with the punched portion.

[0246] In this case, a cut remains on the mica sheet. That is, the mica sheet becomes a shape with a cut in a manner that connects to the outline of the opening.

[0247] Alternatively, mica sheets other than the punched mica sheets can be placed inside the opening.

[0248] Next, the use and configuration method of the battery pack according to the first embodiment of the present invention will be described.

[0249] The use of the battery pack of the first embodiment of the present invention is not particularly limited; for example, it can be used as a power source for electric vehicles.

[0250] Furthermore, in the first embodiment of the present invention, the battery pack is preferably configured such that the safety valve of the battery cell is located on the upper or lower side in the vertical direction.

[0251] When a battery pack is configured with the safety valve in this position, the high-temperature gas from abnormal battery cells naturally and rapidly disperses, making it difficult to trigger a chain reaction of thermal runaway. In other words, from a fail-safe perspective, this can be considered the preferred configuration for the battery pack.

[0252] In the battery pack of the first embodiment of the present invention, the safety valve may be configured either on the bottom side or on the cover side.

[0253] As described above, when configuring the battery pack of the first embodiment of the present invention, from the viewpoint of failure protection, the battery pack is sometimes configured such that the safety valve is located on the upper or lower side of the vertical direction.

[0254] Battery packs are mostly configured with the bottom of the casing or the cover located on the lower side. Therefore, if the safety valve is configured with the bottom or cover located on the lower side of the casing, it is easy for the safety valve to be located on the upper or lower side in the vertical direction.

[0255] (Second Implementation)

[0256] Next, the battery pack according to the second embodiment of the present invention will be described.

[0257] The battery pack of the second embodiment of the present invention differs from the battery pack of the first embodiment of the present invention in that a cut portion is formed on the inorganic fiber pad that extends from one main surface of the stacked mica sheet to another main surface, and when the heat insulation material is viewed from the mica sheet side, at least a portion of the cut portion is located inside the opening.

[0258] Figure 5A This is an enlarged cross-sectional view schematically showing an example of the cross-section of the heat-insulating material of the battery pack according to the second embodiment of the present invention.

[0259] Figure 5B yes Figure 5A A top view of an example of mica sheets contained in the insulation material shown.

[0260] Figure 5C yes Figure 5A A top view of an example of an inorganic fiber pad contained in the insulation material shown.

[0261] Figure 5A The thermal insulation material 140 shown includes an inorganic fiber pad 141 and a mica sheet 142 laminated on the inorganic fiber pad 141.

[0262] A cutout 141a is formed on the inorganic fiber pad 141, which extends from one main surface of the stacked mica sheet 142 to another.

[0263] like Figure 5BAs shown, a plurality of openings 142a are formed in the mica sheet 142, and four mica sheets 150 are arranged inside the openings 142a.

[0264] Mica sheet 142 and mica sheet 150 are bonded to inorganic fiber pad 141 by an adhesive layer (not shown).

[0265] like Figure 5B As shown, the opening 142a is circular. In addition, the four mica sheets 150 are congruent sectors, which together form a circle.

[0266] The four mica sheets 150 are in contact with the outline of the opening 142a and form a circle by contacting each other.

[0267] like Figure 5C As shown, the cut portion 141a is formed on the main surface of the inorganic fiber pad 141 by two line segments intersecting at right angles.

[0268] Furthermore, when the insulation material 140 is viewed from above from the mica sheet 142 side, the cut portion 141a is located inside the opening portion 142a.

[0269] If a cutout 141a is formed on the inorganic fiber pad 141, high-temperature gas from the module (not shown) side can easily reach the mica sheet 150 through the cutout 141a.

[0270] Therefore, it is possible to prevent gas from flowing back through the interior of the inorganic fiber pad 141 and from other safety valves.

[0271] In the thermal insulation material 140, when the inorganic fiber pad 141 is viewed from above, the cut portion 141a can be formed as a line, a straight line, or a curve.

[0272] Linear cuts can be easily formed using tools or similar means.

[0273] In the thermal insulation material 140, the cutout 141a can be formed individually or in multiple forms.

[0274] When multiple cuts 141a are formed, the cuts 141a can contact each other or cross each other.

[0275] If the cutout 141a is formed in this way, high-temperature gas from the module side can easily pass through the inorganic fiber pad 141.

[0276] Furthermore, the cut portion 141a may also be formed along the portion where the mica sheets 150 are in contact with each other. In addition, the portion where the cut portion 141a and the mica sheet 150 are in contact with each other is preferably formed in a straight line.

[0277] Such a mica sheet 150 and cut-out portion 141a can be formed by simultaneously punching an integral mica sheet 142 and an inorganic fiber pad 141.

[0278] The following description uses the accompanying drawings to illustrate other preferred shapes for the cut-out portion, opening, and mica sheet.

[0279] Figure 6A This is a top view schematically showing another example of the cut portion of the inorganic fiber pad formed in the battery pack of the second embodiment of the present invention.

[0280] Figure 6B This is a top view schematically showing the opening of the mica sheet formed in the battery pack of the second embodiment of the present invention and another example of the mica sheet.

[0281] Figure 7A This is a top view schematically showing another example of the cut portion of the inorganic fiber pad formed in the battery pack of the second embodiment of the present invention.

[0282] Figure 7B This is a top view schematically showing the opening of the mica sheet formed in the battery pack of the second embodiment of the present invention and another example of the mica sheet.

[0283] Figure 8A This is a top view schematically showing another example of the cut portion of the inorganic fiber pad formed in the battery pack of the second embodiment of the present invention.

[0284] Figure 8B This is a top view schematically showing the opening of the mica sheet formed in the battery pack of the second embodiment of the present invention and another example of the mica sheet.

[0285] Figure 6A The cut portion 141a1 shown is formed on the inorganic fiber pad 141 by two line segments intersecting at right angles.

[0286] Figure 6B The opening 142a1 shown is circular. In addition, a circular, monolithic mica sheet 150a1 is disposed inside the opening 142a1 so as to completely fill the opening 142a1.

[0287] Figure 7A The cut portion 141a2 shown is formed on the inorganic fiber pad 141 in a manner consisting of a single line segment.

[0288] Figure 7B The opening 142a2 shown is circular. In addition, two semi-circular mica sheets 150a2 are arranged inside the opening 142a2 in such a way that they completely fill the opening 142a2.

[0289] The cut portion 141a2 is formed along the portion where the mica sheets 150a2 come into contact with each other.

[0290] Figure 8A The cut portion 141a3 shown is formed on the inorganic fiber pad 141 by a line segment L1 and four line segments L2, L3, L4 and L5 connected to the line segment L1.

[0291] The points where line segments L1 and L2 connect are the same as the points where line segments L1 and L3 connect, and the angles formed by line segments L1 and L2 and L1 and L3 are the same.

[0292] In addition, the parts where line segment L1 connects to line segment L4 and the parts where line segment L1 connects to line segment L5 are the same, and the angles formed by line segment L1 and line segment L4 and the angles formed by line segment L1 and line segment L5 are the same.

[0293] That is, the cut portion 141a3 is formed into a shape that is linearly symmetrical about the line segment L1.

[0294] Figure 8B The opening 142a3 shown is racetrack shaped. In addition, six mica sheets 150a3 are arranged inside the opening 142a3 in such a way that they completely fill the opening 142a3.

[0295] In addition, each mica sheet 150a3 is shaped like a racetrack when assembled, and the contact portion of the mica sheets 150a3 with each other is formed along the cut portion 141a3.

[0296] exist Figure 7A and Figure 7B as well as Figure 8A and Figure 8B In this design, the cut is formed along the part where the mica sheets come into contact with each other. That is, the cut is consistent with the part where the mica sheets come into contact with each other.

[0297] However, in the battery pack of the second embodiment of the present invention, when the heat insulation material is viewed from the mica sheet side, the portion of the cut portion that contacts the mica sheet may not be the same.

[0298] In the above description, the end of the cut portion 141a is connected to the outline of the opening portion 142a. However, in the battery pack of the second embodiment of the present invention, when the heat insulation material is viewed from the mica sheet side, the cut portion may also be formed to intersect with the outline of the opening portion.

[0299] If the cut is formed in this way, the high-temperature gas from the module side can easily pass through the inorganic fiber pad 141.

[0300] The inorganic fiber mat 141 is preferably made by processing inorganic fibers containing fibers with a melting point of 1000°C or higher into a mat shape.

[0301] As inorganic fibers, silica fibers, alumina fibers, aluminosilicate fibers, and biosoluble fibers are preferred.

[0302] If the inorganic fiber pad 141 is made of such a material, the inorganic fiber has heat resistance, so the inorganic fiber melts due to the heat of the gas and it is difficult to form pores.

[0303] Therefore, when passing through the inorganic fiber pad, the gas can be appropriately dispersed, preventing the gas from reaching the shell at a high temperature.

[0304] Furthermore, since a cutout 141a is formed on the inorganic fiber pad 141, the gas flow path can be adequately ensured even if the inorganic fiber does not melt.

[0305] The preferred materials for the mica sheet 142 and the adhesive layer are the same as those for the mica sheet 42 and the adhesive layer described in the description of the battery pack of the first embodiment of the present invention.

[0306] Next, a method for manufacturing the heat-insulating material included in the battery pack according to the second embodiment of the present invention will be described.

[0307] In the manufacture of this insulation material, inorganic fiber pads and mica sheets are prepared.

[0308] Next, the mica sheet is punched to produce a mica sheet with an opening and a mica sheet.

[0309] It should be noted that when punching mica sheets, the punching can be performed to form only one mica sheet or to form multiple mica sheets. It should also be noted that, alternatively, after punching to form only one mica sheet, it can be further divided into multiple mica sheets by cutting.

[0310] Additionally, cuts are formed on the inorganic fiber pad.

[0311] Next, the mica sheet with the opening is bonded to the main surface of the inorganic fiber pad using an adhesive layer. At this time, the mica sheet is arranged such that the cut portion of the inorganic fiber pad is located inside the opening portion of the mica sheet.

[0312] Then, the mica sheet is bonded to the main surface of the inorganic fiber pad by an adhesive layer in such a way that the mica sheet is housed inside the opening.

[0313] Therefore, it is possible to manufacture heat-insulating materials for the battery pack configured in the second embodiment of the present invention.

[0314] Alternatively, the heat-insulating material included in the battery pack of the second embodiment of the present invention can also be manufactured by the following method.

[0315] In the case of manufacturing thermal insulation materials, the first step is to prepare inorganic fiber pads and mica sheets.

[0316] Next, the mica sheet is punched to produce a mica sheet with an opening and a mica sheet.

[0317] Next, an adhesive layer is used to bond the mica sheet with the opening to the main surface of the inorganic fiber mat. Additionally, the mica sheet is bonded to the main surface of the inorganic fiber mat by means of tucking the mica sheet inside the opening.

[0318] Then, together with the mica sheet, a slit is formed on the inorganic fiber pad. At this point, the mica sheet is divided.

[0319] Therefore, it is possible to manufacture heat-insulating materials for the battery pack configured in the second embodiment of the present invention.

[0320] In addition, in the above method, the cut can also be formed by the intersection of the outlines of the cut and the opening.

[0321] In this case, the mica sheet is formed into a shape with a cutout in a manner that connects with the contour of the opening.

[0322] Alternatively, the heat-insulating material included in the battery pack of the second embodiment of the present invention can also be manufactured by the following method.

[0323] In the case of manufacturing thermal insulation materials, firstly, prepare inorganic fiber mats and mica sheets, and then use an adhesive layer to bond the mica sheets to the main surface of the inorganic fiber mats.

[0324] Next, a blanking die with a first blade and a second blade is prepared. The first blade has a contour that forms an opening only for the mica sheet and a length of the mica sheet. The second blade has a length that forms a cut in the inorganic fiber pad by blanking both the mica sheet and the inorganic fiber pad. That is, a blanking die with two blades, the second blade being longer than the first blade and having a different length, is prepared.

[0325] Then, the mica sheet and the inorganic fiber pad can also be punched from the mica sheet side using the punching die, forming the opening of the mica sheet, the cut of the mica sheet and the inorganic fiber pad in one operation.

[0326] Alternatively, the heat-insulating material included in the battery pack of the second embodiment of the present invention can also be manufactured by the following method.

[0327] In the case of manufacturing thermal insulation materials, firstly, prepare inorganic fiber mats and mica sheets, and then use an adhesive layer to bond the mica sheets to the main surface of the inorganic fiber mats.

[0328] Next, using a cutter that only punches the length of the inorganic fiber pad, the inorganic fiber pad is punched from the side to form a cut.

[0329] Next, using a cutter that only cuts the length of the mica sheet, the mica sheet is cut from the side to form an opening and the mica sheet.

[0330] The resulting mica sheet can be one or more. Alternatively, a single mica sheet can be punched to further divide it into multiple mica sheets.

[0331] (Third implementation method)

[0332] Next, the battery pack according to the third embodiment of the present invention will be described.

[0333] The battery pack of the third embodiment of the present invention differs from the battery pack of the first embodiment and the battery pack of the second embodiment of the present invention described above in that the mica sheet is arranged in such a way that it covers the outline of the opening from the housing side.

[0334] The battery pack of the third embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0335] Figure 9A This is an enlarged cross-sectional view schematically showing an example of the cross-section of the heat-insulating material of the battery pack according to the third embodiment of the present invention.

[0336] Figure 9B This is an enlarged cross-sectional view schematically showing another example of the cross-section of the heat-insulating material of the battery pack according to the third embodiment of the present invention.

[0337] Figure 9C This is an enlarged cross-sectional view schematically showing another example of the cross-section of the heat-insulating material of the battery pack according to the third embodiment of the present invention.

[0338] exist Figure 9A The heat insulation material 240a shown includes an inorganic fiber pad 241 and a mica sheet 242 laminated on the inorganic fiber pad 241.

[0339] An opening 242a is formed in the mica sheet 242, and the mica sheet 250 is arranged to cover the outline of the opening 242a from the housing (not shown) side.

[0340] In addition, mica sheet 250 is bonded to the surface of mica sheet 242 by an adhesive layer (not shown).

[0341] exist Figure 9B In the heat insulation material 240b shown, a cutout 241a is formed on the inorganic fiber pad 241, which extends from one main surface of the stacked mica sheet 242 to another main surface, unlike the heat insulation material 240a described above.

[0342] exist Figure 9C The thermal insulation material 240c shown is different from the thermal insulation material 240b described above in that it has multiple mica sheets 250.

[0343] If the mica sheet is configured in this way, there will be no gap between the mica sheet and the opening, which will easily prevent gas from flowing back between the mica sheet and the opening.

[0344] Apart from the differences described above, the preferred materials of each component of the battery pack in the third embodiment of the present invention are the same as the preferred materials described in the description of the battery pack in the first embodiment of the present invention.

[0345] (Fourth Implementation)

[0346] Next, the battery pack according to the fourth embodiment of the present invention will be described.

[0347] The battery pack of the fourth embodiment of the present invention differs from the inventions of the first to third embodiments described above in that the heat insulation material further includes a third heat insulation sheet, which is laminated on the mica sheet in such a way that it covers the opening from the housing side.

[0348] Hereinafter, the battery pack of the fourth embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0349] Figure 10 This is an enlarged cross-sectional view schematically illustrating an example of a battery pack according to the fourth embodiment of the present invention.

[0350] Figure 10 The battery pack 310 shown includes: a module 320 having a plurality of battery cells 321 and a connection module component 320a connecting the battery cells 321; and a housing 330 for housing the module 320.

[0351] In the battery pack 310, a safety valve 322 is provided in each battery cell 321.

[0352] In addition, in the battery pack 310, a heat insulation material 340 is provided between the module 320 and the housing 330.

[0353] Furthermore, the battery pack 310 is configured such that the safety valve 322 is located on the upper side in the vertical direction. That is, with Figure 1B The battery pack 10 shown is configured upside down.

[0354] The thermal insulation material 340 consists of an inorganic fiber pad 341 as the first thermal insulation sheet, a mica sheet 342 as the second thermal insulation sheet, and a third thermal insulation sheet 343, which are stacked sequentially from bottom to top.

[0355] An opening 342a is formed in the mica sheet 342, and a mica sheet 350 is disposed inside the opening 342a.

[0356] Mica sheet 342 and mica sheet 350 are bonded to the main surface of inorganic fiber pad 341 by an adhesive layer (not shown).

[0357] In addition, the third heat insulation sheet 343 is laminated on the mica sheet 342 in such a way that it covers the opening 342a from the side of the housing 330.

[0358] Next, the function of the third thermal insulation sheet 343 will be explained using the accompanying drawings.

[0359] Figures 11A to 11C The diagram illustrates the principle of preventing thermal runaway cascading in the event of thermal runaway in a battery cell in the battery pack of the fourth embodiment of the present invention.

[0360] like Figure 11A As shown, when a battery cell 321a experiences thermal runaway and generates high-temperature gas from the battery cell 321a, gas G is discharged from safety valve 322a (in... Figure 11A In the diagram, the symbol "G" represents gas, and the arrow indicates the direction of gas flow.

[0361] Then, the gas released from safety valve 322a reaches the insulation material 340.

[0362] The gas G that reaches the insulation material 340 first comes into contact with the inorganic fiber pad 341.

[0363] The inorganic fiber pad 341 is not dense, and there are spaces between the inorganic fibers, so gas G can pass through the inorganic fiber pad 341.

[0364] An opening 342a is formed in the mica sheet 342, which extends through the mica sheet 342. When the mica sheet 342 is viewed from above, the opening 342a is located at a position that overlaps with the safety valve 322.

[0365] Therefore, the gas G passing through the inorganic fiber pad 341 reaches the vicinity of the opening 342a of the mica sheet 342.

[0366] A mica sheet 350 is disposed inside the opening 342a of the mica sheet 342, and the mica sheet 350 is bonded to the inorganic fiber pad 341 by an adhesive layer (not shown).

[0367] The gas G reaching the vicinity of the opening 342a of the mica sheet 342 is at a high temperature, thus thermally decomposing the adhesive layer bonding the mica sheet 350. As a result, the adhesion between the mica sheet 350 and the inorganic fiber pad 341 weakens.

[0368] In addition, air pressure is applied to the mica sheet 350 from the module 320 side toward the housing 330 side.

[0369] The result, such as Figure 11B As shown, mica sheet 350 is peeled off from inorganic fiber pad 341.

[0370] Then, gas G passes through the opening 342a of mica sheet 342 and reaches the third insulation sheet 343.

[0371] Gas G is blocked by the third insulating sheet 343. In addition, the third insulating sheet 343 is pushed upward by gas G in a manner that allows it to leave the mica sheet 342.

[0372] As a result, it is possible to prevent gas G from coming into contact with the housing 330.

[0373] After that, as Figure 11C As shown, gas G diffuses through the gap S formed between the third insulating sheet 343 and the mica sheet 342. Then, the temperature and pressure of gas G decrease.

[0374] As mentioned above Figure 11C As shown, the third heat insulation sheet 343 can be arbitrarily configured as long as it can be pushed upward by the gas G in a way that it leaves the mica sheet 342 to form a gap S.

[0375] For example, the third insulation sheet 343 can be disposed on the mica sheet 342 without being fixed, or it can be disposed on the mica sheet 342 in a manner in which part of it is fixed.

[0376] The third heat insulation sheet 343 can also be composed of sheet components made primarily of magnesium silicate (containing approximately 75% to 85% magnesium silicate by weight) or sheet components made primarily of silicon dioxide.

[0377] (Other implementation methods)

[0378] In the description of the first to fourth embodiments of the present invention above, in the battery pack, when the mica sheet is viewed from above, an opening is located at a position overlapping with a safety valve.

[0379] The battery pack of the present invention only requires that, when viewed from above, one opening of the mica sheet is located at a position that overlaps with at least a portion of a safety valve, or there may be a portion that does not overlap.

[0380] Furthermore, in the description of the first to fourth embodiments of the present invention above, in the battery pack, when the mica sheet is viewed from above, one opening is located at a position overlapping with a safety valve, but multiple openings may also be located at positions that overlap with at least a portion of a safety valve.

[0381] In the description of the first to fourth embodiments of the present invention above, the case where the first heat-insulating sheet is an inorganic fiber pad was described. However, in the battery pack of the present invention, the first heat-insulating sheet may also be composed of, for example, a sheet, paper, board, or the like formed using inorganic particles or a mixture of inorganic particles and inorganic fibers.

[0382] In the description of the first to fourth embodiments of the present invention above, the cases where the second heat-insulating sheet and the cover sheet are both mica sheets were described. However, in the battery pack of the present invention, the second heat-insulating sheet may also be a heat-resistant resin sheet. Additionally, the cover sheet may also be a heat-resistant resin sheet.

[0383] In addition, heat-resistant resin sheets can be made of polyamide resin, polybutylene terephthalate resin, or polypropylene resin.

[0384] The following matters are disclosed in this specification.

[0385] The present invention (1) is a battery pack comprising: a module having a plurality of battery cells each having a safety valve; a housing for housing the module; and a heat insulation material disposed between the module and the housing, characterized in that the heat insulation material comprises a first heat insulation sheet and a second heat insulation sheet laminated thereon, the heat insulation material being configured such that the first heat insulation sheet is located on the module side and the second heat insulation sheet is located on the housing side, a plurality of openings are formed in the second heat insulation sheet, and a cover sheet covering at least a portion of the openings is disposed in each of the plurality of openings, the cover sheet being bonded to the first heat insulation sheet and / or the second heat insulation sheet by an adhesive layer, and when the second heat insulation sheet is viewed from above, one of the openings is located at a position overlapping at least a portion of one of the safety valves.

[0386] The present invention (2) is the battery pack of the present invention (1), wherein at least one of the cover sheets is disposed inside each of the plurality of openings.

[0387] The present invention (3) is the battery pack described in the present invention (2), wherein a plurality of the cover sheets are disposed inside each of the plurality of openings.

[0388] The present invention (4) is the battery pack of the present invention (3), wherein at least a portion of the plurality of the cover sheets are arranged in contact with each other.

[0389] The present invention (5) is a battery pack in any combination with any one of the present inventions (1) to (4), wherein the cover sheet is configured such that at least a portion contacts the contour of the opening.

[0390] The present invention (6) is a battery pack in any combination with any one of the present inventions (1) to (4), wherein the cover is configured to cover the outline of the opening from the housing side.

[0391] The present invention (7) is a battery pack according to any one of the present inventions (1) to (6), wherein a cut portion is formed in the first heat insulation sheet, which extends from the main surface of the second heat insulation sheet to another main surface, and when the heat insulation material is viewed from the side of the second heat insulation sheet, at least a portion of the cut portion is located inside the opening.

[0392] The present invention (8) is the battery pack described in the present invention (7), wherein, when the heat insulation material is viewed from the second heat insulation sheet side, the cut portion is formed in a linear shape.

[0393] The present invention (9) is the battery pack described in the present invention (8), wherein, when the heat insulation material is viewed from the second heat insulation sheet side, the cut portion is formed to intersect the contour of the opening portion.

[0394] The present invention (10) is a battery pack according to any one of the present inventions (7) to (9), wherein a plurality of the cut portions are formed in the first heat insulation sheet.

[0395] The present invention (11) is a battery pack according to any one of (7) to (10), wherein, when the heat insulation material is viewed from the second heat insulation sheet side, a plurality of linear cuts are formed in the first heat insulation sheet, and at least a portion of the plurality of cuts are in contact with each other.

[0396] The present invention (12) is a battery pack according to any one of the present inventions (7) to (11), wherein a plurality of the cover sheets are disposed inside the opening, at least a portion of the plurality of cover sheets are in contact with each other, and when the heat insulation material is viewed from the second heat insulation sheet side, the cut is formed along the portion of the cover sheets that are in contact with each other.

[0397] The present invention (13) is the battery pack of the present invention (12), wherein, when the heat insulation material is viewed from the second heat insulation sheet side, the portions of the cover sheets that are in contact with each other are formed in a straight line.

[0398] The present invention (14) is a battery pack according to any one of the present inventions (1) to (13), wherein the top view shape of the opening is selected from at least one shape selected from the group consisting of triangle, quadrilateral, hexagon, circle, ellipse and racetrack shape.

[0399] The present invention (15) is a battery pack according to any one of the present invention (1) to (14), wherein the first heat insulation sheet is an inorganic fiber pad.

[0400] The present invention (16) is the battery pack described in the present invention (15), wherein the inorganic fiber pad is made by processing inorganic fibers containing at least one type of fiber selected from silica fiber, glass fiber, alumina fiber, aluminosilicate fiber, basalt fiber, rock wool, and biosoluble fiber into a pad shape.

[0401] The present invention (17) is the battery pack described in the present invention (15) or (16), wherein the inorganic fiber pad is made by processing inorganic fibers containing fibers with a melting point of 1000°C or higher into a pad shape.

[0402] The present invention (18) is a battery pack according to any one of the present inventions (15) to (17), wherein the inorganic fiber pad is made by processing inorganic fibers containing fibers with a melting point of less than 1000°C into a pad shape.

[0403] The present invention (19) is a battery pack according to any one of the present inventions (1) to (18), wherein the second heat insulation sheet is a mica sheet.

[0404] The present invention (20) is a battery pack according to any one of the present invention (1) to (18), wherein the second heat insulation sheet is a heat-resistant resin sheet.

[0405] The present invention (21) is a battery pack according to any one of the present inventions (1) to (20), wherein the cover sheet is made of the same material as the second heat insulation sheet.

[0406] The present invention (22) is a battery pack according to any one of the present inventions (1) to (21), wherein the adhesive layer comprises an organic adhesive layer.

[0407] The present invention (23) is a battery pack according to any one of the present inventions (1) to (22), wherein the heat insulation material further comprises a third heat insulation sheet, the third heat insulation sheet being laminated on the second heat insulation sheet in such a way as to cover the opening from the housing side.

[0408] The present invention (24) is a battery pack according to any one of the present inventions (1) to (23), wherein the housing has a receiving portion consisting of a bottom and a side wall portion and a cover portion covering the receiving portion, and the safety valve is configured to be located on the bottom side or on the cover side.

[0409] [Example]

[0410] <Cracking Test 1>

[0411] (Example 1-1)

[0412] Prepare an inorganic fiber mat with a thickness of 5 mm made of silica fibers.

[0413] In addition, prepare a mica sheet with a thickness of 0.1 mm and punch it to form a circular opening with a diameter of 8 mm.

[0414] Mica sheets with openings are bonded to the main surface of the inorganic fiber pad using polyamide-based organic materials (heat resistant temperature 100℃).

[0415] In addition, using polyamide-based organic materials (heat resistant temperature 100°C), the punched circular fragments (mica sheets) are bonded to the main surface of the inorganic fiber pad by being housed inside the opening.

[0416] Next, the mica sheet, mica sheet and inorganic fiber pad are punched out by two 30mm line segments intersecting at right angles, with the intersection point aligned with the center of the mica sheet.

[0417] Following the above steps, the thermal insulation material of Example 1-1 is produced. The obtained thermal insulation material is shown below. Figure 12 .

[0418] Figure 12 This is a photograph of the thermal insulation material of Embodiment 1-1 of the present invention, viewed from the mica sheet side.

[0419] (Examples 1-2)

[0420] Prepare an inorganic fiber mat with a thickness of 5 mm made of silica fibers.

[0421] In addition, prepare a mica sheet with a thickness of 0.1 mm, and punch it to form a circular opening with a diameter of 8 mm. Then, remove the punched circular fragment (mica sheet).

[0422] Mica sheets with openings are bonded to the main surface of the inorganic fiber pad using polyamide-based organic materials (heat resistant temperature 100℃).

[0423] Next, the mica sheet and inorganic fiber pad are punched out using two 30mm line segments that intersect at right angles, with the intersection point aligned with the center of the opening.

[0424] Then, using a polyamide-based organic material (heat resistant temperature 100°C), the mica sheet is bonded to the main surface of the inorganic fiber pad in a manner that conceals it inside the opening.

[0425] Following the above procedures, the thermal insulation materials of Examples 1-2 are produced. The obtained thermal insulation materials are shown below. Figure 13 .

[0426] Figure 13 These are photographs of the thermal insulation materials of Embodiments 1-2 of the present invention, viewed from the mica sheet side.

[0427] A cracking test 1 was conducted using the heat insulation materials of Examples 1-1 and 1-2 to simulate the situation of gas being ejected from the safety valve of the battery cell.

[0428] Figure 14 This is an illustrative diagram schematically showing cracking test 1.

[0429] like Figure 14 As shown, each heat insulation material 40 is clamped and fixed using a first clamp having a first opening 61a and a second clamp having a second opening 62a. The first opening 61a and the second opening 62a are circles with a radius of 10 mm.

[0430] The thermal insulation material 40 is configured such that the mica sheet 42 is located on the side of the second clamp 62.

[0431] Furthermore, when viewed from the side of the second clamp 62, the center of gravity of the first opening 61a, the center of gravity of the opening 42a of the mica sheet 42, and the center of gravity of the second opening 62a are the same.

[0432] Then, the insulation material 40 is compressed so that its thickness is 3 mm.

[0433] Next, the insulation material 40 is heated at 250°C. As a result, the adhesive strength of the polyamide-based organic material weakens, and the mica sheet easily separates from the inorganic fiber pad.

[0434] Next, a gas pipe 70 with a gas valve 71 is connected to the first opening 61a.

[0435] Then, air at 25°C is supplied to the gas pipe to bring the air pressure to 200 kPa before the gas valve 71 is opened. Then, the gas valve 71 is opened to inject air into the insulation material 40.

[0436] Measure the air pressure after the air valve 71 is opened.

[0437] In the test using the thermal insulation material of Example 1-1, the air pressure after the air valve was opened was 90 kPa.

[0438] In the tests using the insulation materials of Examples 1-2, the air pressure after the air valve was opened was 94 kPa.

[0439] Additionally, in each embodiment, it was observed whether the mica sheet peeled off from the inorganic fiber pad. The results are shown below. Figure 15A , Figure 15B , Figure 16A as well as Figure 16B .

[0440] Figure 15A This is a photograph taken from the second clamp side before the air valve is opened during a gas pressure cracking test using the thermal insulation material of Example 1-1.

[0441] Figure 15B This is a photograph taken from the second clamp side after the air valve is opened during a gas pressure cracking test using the thermal insulation material of Example 1-1.

[0442] Figure 16A This is a photograph taken from the second clamp side before the air valve is opened during a gas pressure cracking test using the thermal insulation material of Examples 1-2.

[0443] Figure 16B This is a photograph taken from the second clamp side after the air valve is opened during a gas pressure cracking test using the thermal insulation material of Examples 1-2.

[0444] like Figure 15A , Figure 15B , Figure 16A and Figure 16B As shown, when using either the insulation material of Example 1-1 or the insulation material of Example 1-2, the mica sheet was observed to peel off from the inorganic fiber pad.

[0445] Based on this result, it is suggested that in battery packs using the thermal insulation materials of Examples 1-1 and 1-2, when high-temperature gas is ejected from the safety valve due to thermal runaway, the mica sheet peels off from the inorganic fiber pad, and the gas disperses between the thermal insulation material and the shell.

[0446] <Cracking Test 2>

[0447] Examples 2-1 to 2-3 and Comparative Example 2-1

[0448] Prepare an inorganic fiber pad with a thickness of 5 mm made of silica fiber and a mica sheet with a thickness of 0.1 mm.

[0449] Next, as Figure 17A and Figure 17B , Figure 18A and Figure 18B , Figure 19A and Figure 19B as well as Figure 20A and Figure 20B As shown, the inorganic fiber pad and mica sheet are punched to form a slit portion 41a, an opening portion 42a, and a mica sheet 50. (Additionally, in...) Figure 17A and Figure 20A In the case where no slits are provided in the inorganic fiber pad, Figure 20B (In the case of mica sheets, no openings are provided).

[0450] Figure 17A This is a schematic top view of the inorganic fiber mat of Example 2-1.

[0451] Figure 17B This is a schematic top view of the opening of the mica sheet in Embodiment 2-1.

[0452] Figure 18A This is a schematic top view showing the cut portion of the inorganic fiber pad of Example 2-2.

[0453] Figure 18B This is a schematic top view of the opening of the mica sheet in Embodiment 2-2.

[0454] Figure 19A This is a schematic top view showing the cut portion of the inorganic fiber pad of Examples 2-3.

[0455] Figure 19B This is a schematic top view of the opening of the mica sheet in Examples 2-3.

[0456] Figure 20A This is a schematic top view of the inorganic fiber pad of Comparative Example 2-1.

[0457] Figure 20B This is a schematic top view of the mica sheet of Comparative Example 2-1.

[0458] Will Figure 17A The inorganic fiber pad shown and Figure 17B The mica sheets shown are grouped together, and the mica sheets with openings are bonded to the main surface of the inorganic fiber pad using a polyamide-based organic material (heat resistant temperature 100°C).

[0459] In addition, using polyamide-based organic materials (heat resistant temperature 100°C), the punched circular fragments (mica sheets) are bonded to the main surface of the inorganic fiber pad by being housed inside the opening.

[0460] After the above procedures, the heat insulation material of Example 2-1 is produced.

[0461] Similarly, Figure 18A The inorganic fiber pad shown and Figure 18B The mica sheets shown are used as a group to make the thermal insulation material of Example 2-2.

[0462] In addition, similarly, Figure 19A The inorganic fiber pad shown and Figure 19B The mica sheets shown are used as a group to produce the thermal insulation materials of Examples 2-3.

[0463] In addition, similarly, Figure 20A The inorganic fiber pad shown and Figure 20B The mica sheets shown are used as a group. The mica sheets are bonded to the main surface of the inorganic fiber pad using a polyamide-based organic material (heat resistance temperature 100°C) to make the heat insulation material of Comparative Example 2-1.

[0464] Using the heat insulation materials of Examples 2-1 to 2-3 and Comparative Example 2-1, a cracking test 2 was conducted simulating the situation where gas is ejected from the safety valve of the battery cell.

[0465] Figure 21 This is a schematic diagram illustrating the cracking test 2.

[0466] like Figure 21 As shown, in the cracking test 2, each insulation material 40 is clamped and fixed using a first clamp having a first opening 61a and a second clamp 62 having a second opening 62a. At this time, an inorganic fiber pad 41 is placed on the side of the first clamp 61, and a mica sheet 42 is placed on the side of the second clamp 62.

[0467] Furthermore, when viewed from the side of the second clamp 62, the center of gravity of the first opening 61a, the center of gravity of the opening 42a of the mica sheet 42, and the center of gravity of the second opening 62a are the same.

[0468] Then, the insulation material 40 is compressed so that its thickness is 3 mm.

[0469] Subsequently, heated alumina particles are sprayed from the sandblasting device 80 into the heat insulation material through the first opening 61a.

[0470] In addition, the conditions for spray coating are as follows.

[0471] Spraying conditions

[0472] Carrier gas: Acetylene gas

[0473] Carrier gas temperature: 3000℃

[0474] Sandblasting particles: alumina particles

[0475] Spraying distance: 150mm

[0476] Spraying time: 30 seconds

[0477] In addition, the surface temperature of the inorganic fiber pad is 1300°C when the heated alumina particles reach it.

[0478] After spraying, observe whether the mica sheet 50 peels off from the inorganic fiber pad 41 (whether the sprayed material can pass through the heat insulation material) and evaluate it.

[0479] The evaluation criteria are as follows. The evaluation results are shown in Table 1.

[0480] <Evaluation Criteria>

[0481] ◎: Mica sheets are peeled off from the inorganic fiber pad, allowing the sprayed material to pass fully through the insulation material.

[0482] 〇: The mica sheet is peeled off from the inorganic fiber pad. The sprayed material can pass through the heat insulation material, but some of the sprayed material remains (reflects) as a trace.

[0483] ×: The sprayed material is reflected by the heat insulation material and cannot pass through the heat insulation material.

[0484] [Table 1]

[0485] As shown in Table 1, in each embodiment where an opening is provided on the mica sheet, it is clear that the sprayed material passes through a heat-insulating material.

[0486] Based on this result, it is suggested that in the battery pack using the heat insulation materials of Examples 2-1 to 2-3, when high-temperature gas is ejected from the safety valve due to thermal runaway, the gas passes through the heat insulation material and is dispersed between the heat insulation material and the shell.

[0487] Label Explanation

[0488] 10, 310: Battery pack; 20, 320: Module; 20a, 320a: Connecting module component; 20b: Busbar; 21, 21a, 321, 321a: Battery cell; 22, 22a, 322, 322a: Safety valve; 23: Terminal; 30, 330: Housing; 31: Storage section; 31b: Bottom; 31s: Side wall; 32: Cover; 40, 140, 240a, 240b, 240c, 340: Thermal insulation material; 41, 141, 241, 341: Inorganic fiber pad; 42, 142, 242, 342: Mica sheet; 42a, 142a, 142a1, 142a2, 142a 3、242a, 342a: Openings; 50, 50a, 50b1, 50b2, 50b3, 50b4, 50c1, 50c2, 50d, 50e, 150, 150a1, 150a2, 150a3, 250, 350: Mica sheets; 61: First clamp; 61a: First opening; 62: Second clamp; 62a: Second opening; 70: Gas pipe; 71: Gas valve; 80: Sandblasting device; 141a, 141a1, 141a2, 141a3, 241a: Cutouts; 343: Third insulation sheet.

Claims

1. A battery pack, comprising: The module has multiple battery cells, each equipped with a safety valve; A housing that houses the module; and Thermal insulation material is disposed between the module and the housing. Its features are, The thermal insulation material comprises a first thermal insulation sheet and a second thermal insulation sheet laminated on the first thermal insulation sheet. The thermal insulation material is configured such that the first thermal insulation sheet is located on the module side and the second thermal insulation sheet is located on the shell side. The second heat insulation sheet has multiple openings that penetrate the second heat insulation sheet. Each of the plurality of openings is provided with a cover sheet that covers at least a portion of the opening. The cover sheet is bonded to the first insulation sheet and / or the second insulation sheet via an adhesive layer. When the second insulation sheet is viewed from above, one of the openings is located at a position that overlaps with at least a portion of one of the safety valves.

2. The battery pack according to claim 1, wherein, At least one of the cover sheets is disposed on the inner side of each of the plurality of openings.

3. The battery pack according to claim 2, wherein, A plurality of cover plates are disposed on the inner side of each of the plurality of openings.

4. The battery pack according to claim 3, wherein, At least a portion of the plurality of cover sheets are configured to be in contact with each other.

5. The battery pack according to any one of claims 1 to 4, wherein, The cover is configured such that at least a portion of it contacts the contour of the opening.

6. The battery pack according to any one of claims 1 to 4, wherein, The cover is configured to cover the outline of the opening from the side of the housing.

7. The battery pack according to any one of claims 1 to 6, wherein, A cutout is formed in the first heat insulation sheet, extending from one main surface of which the second heat insulation sheet is laminated to another main surface. When the insulation material is viewed from above from the side of the second insulation sheet, at least a portion of the cut is located inside the opening.

8. The battery pack according to claim 7, wherein, When the insulation material is viewed from above from the side of the second insulation sheet, the cut portion is formed as a line.

9. The battery pack according to claim 8, wherein, When the insulation material is viewed from above from the side of the second insulation sheet, the cut is formed to intersect the contour of the opening.

10. The battery pack according to any one of claims 7 to 9, wherein, The first heat insulation sheet has a plurality of cuts.

11. The battery pack according to any one of claims 7 to 10, wherein, When viewing the insulation material from above the second insulation sheet side, The first heat insulation sheet has multiple linear cutouts. At least a portion of the plurality of cuts are in contact with each other.

12. The battery pack according to any one of claims 7 to 11, wherein, A plurality of the cover plates are disposed on the inner side of the opening. At least a portion of the plurality of said cover sheets is in contact with each other. When the insulation material is viewed from above from the second insulation sheet side, the cut is formed along the portion of the cover sheet that is in contact with each other.

13. The battery pack according to claim 12, wherein, When the insulation material is viewed from above from the side of the second insulation sheet, the portions of the cover sheets that are in contact with each other form a straight line.

14. The battery pack according to any one of claims 1 to 13, wherein, The top view shape of the opening is selected from at least one shape chosen from the group consisting of triangles, quadrilaterals, hexagons, circles, ellipses and racetracks.

15. The battery pack according to any one of claims 1 to 14, wherein, The first heat insulation sheet is an inorganic fiber pad.

16. The battery pack according to claim 15, wherein, The inorganic fiber mat is made by processing inorganic fibers, which include at least one type of fiber selected from silica fiber, glass fiber, alumina fiber, aluminosilicate fiber, basalt fiber, rock wool, and biosoluble fiber, into a mat shape.

17. The battery pack according to claim 15 or 16, wherein, The inorganic fiber mat is made by processing inorganic fibers containing fibers with a melting point of 1000°C or higher into a mat shape.

18. The battery pack according to any one of claims 15 to 17, wherein, The inorganic fiber mat is made by processing inorganic fibers containing fibers with a melting point of less than 1000°C into a mat shape.

19. The battery pack according to any one of claims 1 to 18, wherein, The second heat insulation sheet is a mica sheet.

20. The battery pack according to any one of claims 1 to 18, wherein, The second heat insulation sheet is a heat-resistant resin sheet.

21. The battery pack according to any one of claims 1 to 20, wherein, The cover sheet is made of the same material as the second heat insulation sheet.

22. The battery pack according to any one of claims 1 to 21, wherein, The adhesive layer comprises an organic adhesive layer.

23. The battery pack according to any one of claims 1 to 22, wherein, The insulation material also includes a third insulation sheet. The third insulation sheet is stacked on the second insulation sheet in such a way that it covers the opening from the housing side.

24. The battery pack according to any one of claims 1 to 23, wherein, The housing has a storage section consisting of a bottom and side walls, and a cover section that covers the storage section. The safety valve is configured either on the bottom side or on the cover side.

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