Battery Module and Battery Pack

Abstract

To provide a battery module capable of preventing transmission of explosion to other battery cells when gas is released from one of multiple battery cells.SOLUTION: A battery module 1 includes multiple battery cells 2 arranged side by side with insulation members 4 in between in a battery case 3. A safety valve 25 is provided on the top surface 22 of each battery cell 2 for releasing the gas inside each battery cell 2 due to the increase of the internal pressure in each battery cell 2. When the safety valve 25 of any one of the plurality of battery cells 2 is opened, an insulating film for preventing transmission of an explosion is formed over the top surface 22 of the battery cells 2 other than the battery cell 2 of which the safety valve 25 is opened by the gas released from the battery cell 2.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery module in which a plurality of battery cells arranged side by side in the lateral direction via a heat insulating member are housed in a battery case, and a battery pack including the battery module.

Background Art

[0002] Conventionally, for high-output and high-capacity batteries such as those used for driving a vehicle, battery modules configured by combining a plurality of single cells (battery cells) and battery packs including the battery modules have been known. In such a battery module or battery pack, if one battery cell causes a thermal runaway (smoke generation), there is a possibility that adjacent battery cells will also cause a thermal runaway. For this reason, it is required that a battery module or battery pack suppress a chain reaction of thermal runaway (serial explosion) of adjacent battery cells when one battery cell undergoes thermal runaway. For example, Patent Document 1 discloses a battery module (battery pack) in which a thermal runaway prevention sheet is disposed between adjacent battery cells to prevent or suppress heat transfer to adjacent battery cells and serial explosion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-mentioned Patent Document 1, heat transfer and continuous explosion in the lateral direction between adjacent battery cells can be prevented. However, there is room for improvement in preventing continuous explosion through the space above the battery cells. On the upper surface of each battery cell, a safety valve may be provided to release the internal gas and smoke to reduce the internal pressure when the internal pressure of each battery cell rises, for example, when heat is generated and smoke is emitted due to internal short circuit or overcharging. In a battery module or battery pack having such battery cells, the gas released from the safety valve of some battery cells may be transmitted to other battery cells through the space above the battery cells, which may cause continuous explosion.

[0005] The present case was created in view of the above problems, and one of its purposes is to prevent continuous explosion of other battery cells when gas is released from any of the plurality of battery cells. Note that, not limited to this purpose, it is also another object of the present case to exhibit operational effects that are not obtainable by conventional techniques and that are derived from each configuration shown in the embodiments for implementing the invention described below.

Means for Solving the Problems

[0006] The disclosed battery module and battery pack can be realized as the following disclosed embodiments or application examples, and solve at least part of the above problems. (1) In the battery module disclosed herein, in a battery module in which a plurality of battery cells arranged side by side in the lateral direction via a heat insulating member are accommodated in a battery case, on the upper surface of each of the battery cells, a safety valve is provided to open due to an increase in the internal pressure of each battery cell and release the gas in each battery cell. When the safety valve of any one of the plurality of battery cells opens, a heat insulating film for preventing continuous explosion is formed on the upper surface of the other battery cells other than the battery cell whose safety valve has opened by the released gas of the battery cell whose safety valve has opened. The battery case includes a lid portion that covers the plurality of battery cells above the upper surfaces of the plurality of battery cells. The member constituting the heat insulation film is provided on the lid portion, and the heat insulation film is formed by the member falling onto the upper surfaces of the plurality of battery cells due to the released gas.

[0008] ( 2)The member is the lid portion, and the lid portion is provided at a position on the outer peripheral portion of the battery case that does not overlap with the side wall portion of the battery case to support the lid portion, and a smoke exhaust portion provided directly above the safety valve of each battery cell. It is preferable to include. In this case, the lid portion causes the support portion to first melt and fall due to the released gas, and the smoke exhaust portion directly above the battery cell with the opened safety valve melts after the support portion to form a smoke exhaust port for releasing the released gas outside the battery case. It is preferable to form the heat insulating film.

[0009] ( 3 )It is preferable that the support portion is formed of a resin having a lower melting point than the other portions of the lid portion other than the support portion of the lid portion. ( 4 )It is preferable that the support portion is formed thinner than the other portions of the lid portion other than the support portion of the lid portion.

[0010] ( 5 )On the surface of the lid portion facing the battery cell side, it is preferable that a plurality of packages in which a ceramic and a thermosetting resin are both encapsulated in a film that is easily dissolved by the released gas are provided. In this case, the member is preferably the ceramic and the thermosetting resin. ( 6 )It is preferable that the package is disposed at a position shifted from directly above the safety valve of each battery cell. ( 7 )The battery pack disclosed herein includes a plurality of the battery modules described in any one of (1) to ( 6 ) above.

Advantages of the Invention

[0011] According to the disclosed battery module and battery pack, when gas is released from any one of the plurality of battery cells, it is possible to prevent a continuous explosion to other battery cells.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0013] A battery module and a battery pack as embodiments will be described with reference to the drawings. The embodiments described below are merely examples, and are not intended to exclude various modifications or application of techniques not specified in the following embodiments. Each configuration of the present embodiment can be modified in various ways without departing from the spirit of the invention. In addition, the configurations can be selected or combined as necessary.

[0014] The battery module of the embodiment includes a plurality of battery cells, and the battery pack includes the battery module. When any one of the plurality of battery cells generates heat and emits smoke due to, for example, an internal short circuit or overcharging, the battery module has a function of preventing other battery cells other than the battery cell from exploding continuously due to the gas (hereinafter also referred to as "emitted gas") emitted from the battery cell. On the upper surface of each battery cell, a safety valve is provided that opens due to an increase in the internal pressure of each battery cell and discharges the gas inside each battery cell. In the battery module, when the safety valve of any one of the plurality of battery cells opens, a heat insulation film for preventing continuous explosion is formed on the upper surface of other battery cells other than the battery cell. Thereby, since the heat of the emitted gas is suppressed from being transmitted to other battery cells through the space above the battery cell, continuous explosion of other battery cells can be suppressed.

[0015] Note that the phrase "a heat insulation film for preventing continuous explosion is formed on the upper surface of the other battery cells other than the battery cell" in the claims is not intended to mean that no heat insulation film is formed on the upper surface of the "battery cell". This description is intended to form a heat insulation film on at least the "upper surface of the other battery cells". That is, the configuration intended by the above description includes a configuration in which a heat insulation film is also formed on a part of the upper surface of the "battery cell" including the "upper surface of the other battery cells".

[0016] [1. First Embodiment] [1-1. Configuration] The battery module 1 as the first embodiment is shown in FIG. 1. Although not shown in the figure, the battery pack is configured by housing a plurality of battery modules 1 in a casing, and is mounted, for example, under the floor of a vehicle (not shown). The battery pack containing a plurality of battery modules 1 is used as a driving battery for the vehicle. This vehicle is a hybrid vehicle (hybrid electric vehicle, HEV, Hybrid Electric Vehicle) or a plug-in hybrid vehicle (plug-in hybrid electric vehicle, PHEV, Plug-in Hybrid Electric Vehicle) equipped with an engine and a motor as drive sources, a generator as a power generation device, and a battery (battery pack) as a power storage device, or an electric vehicle (BEV, Battery EV) equipped with a motor as a drive source and a battery as a power storage device. A plug-in hybrid vehicle means a hybrid vehicle capable of external charging of the battery or external power supply from the battery. The plug-in hybrid vehicle and the electric vehicle are provided with a charging port (inlet) for inserting a charging cable for supplying power from an external charging facility and an outlet for external power supply.

[0017] As shown in FIG. 1, the battery module 1 is configured by housing a plurality of battery cells 2 in a battery case 3 (hereinafter simply referred to as "case 3") in a state where the plurality of battery cells 2 are arranged side by side in the horizontal direction via a heat insulating member 4. In the present embodiment, the member constituting the above-described explosion prevention heat insulating film is the lid portion 6 of the case 3 described later. In the battery module 1 of the first embodiment, when any one of the plurality of battery cells 2 generates heat and emits smoke, the lid portion 6 of the case 3 drops due to the gas released from the battery cell 2. Thereby, the lid portion 6 functions as an explosion prevention heat insulating film that prevents heat transfer between the space above the battery cell 2 and each battery cell 2.

[0018] Each battery cell 2 is, for example, a rectangular battery such as a lithium-ion secondary battery, and includes a container portion 21 and an upper surface portion 22 (upper surface) that seals the container portion 21 from above. The container portion 21 is, for example, a pouch-type film in which an aluminum foil is coated with a resin. The container portion 21 may be a bottomed cylindrical shape formed of a metal such as stainless steel. Inside the container portion 21, an electrode body (power storage element) including a positive electrode plate, a negative electrode plate, and a separator is housed together with an electrolytic solution. In FIGS. 1 to 3 and FIGS. 4 and 5 related to the battery module 1' of the second embodiment described later, only the upper surface portions 22, 22' of the battery cells 2, 2' are shown as cross-sectional views, and the other portions are shown in a simplified manner. Also, in FIGS. 1 to 5, a battery module 1, 1' in which eight battery cells 2, 2' are arranged in parallel in the horizontal direction (left-right direction in the figure) inside the cases 3, 3' is illustrated, but the number of battery cells 2, 2' is not limited to this.

[0019] On the upper surface portion 22, a positive electrode terminal 23 and a negative electrode terminal 24 connected to the positive electrode plate and the negative electrode plate of the electrode body housed in the container portion 21 respectively project upward. The plurality of battery cells 2 are connected in series with each other via the positive electrode terminal 23 and the negative electrode terminal 24 respectively. Further, a safety valve 25 is provided between the positive electrode terminal 23 and the negative electrode terminal 24 on the upper surface portion 22. The safety valve 25 is formed relatively more fragile than other portions of the upper surface portion 22, and is configured to open, for example, when the internal pressure of the container portion 21 reaches a predetermined value when an internal short circuit (short) occurs inside the container portion 21. Thereby, even when the internal pressure of the container portion 21 rises, the gas inside the container portion 21 jets out to the outside from the opened safety valve 25. Therefore, it is possible to suppress the rupture of the container portion 21 due to the increase in internal pressure.

[0020] The case 3 is an outer shell of the battery module 1 configured by combining a lid portion 6 from above the tray portion 5. The case 3 is formed of a metal such as stainless steel, for example, excluding the support portion 61 and the smoke exhaust portion 62 described later.

[0021] The tray portion 5 is a box-shaped container with an open upper surface. The tray portion 5 has a flat bottom wall portion 51 and side wall portions 52 erected from the peripheral edge of the bottom wall portion 51. The bottom wall portion 51 has, for example, a substantially rectangular shape in a top view. The side wall portions 52 have a rectangular tube shape corresponding to the shape of the bottom wall portion 51. The plurality of battery cells 2 are placed on the bottom wall portion 51. In FIG. 1, a plurality of battery cells 2 arranged side by side in the left-right direction are illustrated, but the plurality of battery cells 2 may be arranged side by side in a direction orthogonal to the plane of the paper. That is, the above-mentioned "lateral direction" means a direction along the bottom wall portion 51 of the case 3.

[0022] The lid portion 6 is a member that covers all of the plurality of battery cells 2 above the battery cells 2. The lid portion 6 of the present embodiment has a substantially rectangular shape in a top view corresponding to the shape of the above-mentioned tray portion 5 and has a flat plate shape that fits inside the side wall portions 52 of the tray portion 5. That is, the lid portion 6 of the present embodiment is arranged so as not to overlap with the side wall portions 52 in the lateral direction. The lid portion 6 is arranged so as to form a space between the upper surface portions 22 of the plurality of battery cells 2 above the upper surface portions 22 of the plurality of battery cells 2.

[0023] On the lid portion 6, at the outer peripheral portion that forms its outer shape in a top view, a support portion 61 is provided at a position that does not overlap with the side wall portions 52 in the lateral direction to support the lid portion 6. As described above, since the lid portion 6 of the present embodiment fits inside the side wall portions 52 of the tray portion 5, the support portion 61 forms the outer peripheral portion of the lid portion 6 itself. The support portion 61 supports the lid portion 6 by being adhered to the inner surface of the side wall portion 52. The lid portion 6 is supported by the support portion 61 and its position is fixed, and the case 3 is sealed by the support portion 61 being adhered to the inner surface of the side wall portion 52.

[0024] The support portion 61 is configured to be more easily melted by the released gas than the portions of the lid portion 6 other than the support portion 61. As a method of configuring the support portion 61, for example, the portion constituting the support portion 61 of the lid portion 6 may be configured by molding with a resin having a lower melting point than the portions other than the support portion 61. Alternatively, the support portion 61 may be configured by forming only the portion constituting the support portion 61 to be thinner than the portions other than the support portion 61. Or, these may be combined for configuration.

[0025] Further, on the lid portion 6, directly above the safety valve 25 of each battery cell 2, a smoke exhaust portion 62 that is more easily melted by the released gas is provided next to the support portion 61. The smoke exhaust portion 62 may be formed, for example, of a resin that has a higher melting point than the support portion 61 and a lower melting point than the portions of the lid portion 6 other than the support portion 61 and the smoke exhaust portion 62. Also, the smoke exhaust portion 62 may be configured to have a thicker wall than the support portion 61 and a thinner wall than the portions of the lid portion 6 other than the support portion 61 and the smoke exhaust portion 62. Alternatively, the smoke exhaust portion 62 may be configured by combining these to be more easily melted next to the support portion 61.

[0026] The heat insulating member 4 is a member that suppresses the heat transfer to adjacent battery cells 2. The heat insulating member 4 is formed, for example, of a ceramic material. In the present embodiment, a heat insulating member 4 standing from the bottom wall portion 51 of the case 3 to the position of the upper surface portion 22 of the battery cell 2 is illustrated. Note that the shape of the heat insulating member 4 is not particularly limited as long as it suppresses the heat transfer between adjacent battery cells 2. Also, a cooling path through which cooling water for cooling each battery cell 2 flows may be provided between adjacent battery cells 2. Further, a fan or a ventilation path for air-cooling each battery cell 2 may be provided in the case 3.

[0027] [1-2. Operation] Next, the operation of the above-described battery module 1 when one of the plurality of battery cells 2 generates heat and emits smoke will be described.

[0028] For example, when one of the plurality of battery cells 2 (hereinafter referred to as the "smoking cell 2") generates heat and emits smoke due to an internal short circuit, overcharging, etc., as shown in FIG. 2, the internal pressure of the container portion 21 of the smoking cell 2 rises, and the safety valve 25 opens. As a result, high-temperature released gas jets out from the safety valve 25 of the smoking cell 2, and the space between the battery cell 2 and the lid portion 6 is filled with the released gas. The lid portion 6 is exposed to the high-temperature released gas, or due to the pressure of the released gas, the support portion 61 of the lid portion 6 that is most easily melted melts. Thereby, the support of the lid portion 6 by the support portion 61 is released.

[0029] When the support by the support portion 61 is released, as shown in FIG. 3, the lid portion 6 drops downward. Thereby, the lid portion 6 becomes a heat insulating film that insulates between the battery cell 2 and the space above it. At this time, the smoke exhaust portion 62 of the lid portion 6 located directly above the smoke generating cell 2 is exposed to the high-temperature discharge gas ejected from the smoke generating cell 2 or dissolved by the pressure of the discharge gas. Thereby, a smoke exhaust port 62h through which the discharge gas can flow is formed directly above the smoke generating cell 2.

[0030] The discharge gas of the smoke generating cell 2 is discharged to the outside of the case 3 from this smoke exhaust port 62h. At this time, outside the case 3, the discharge gas also spreads above the battery cell 2 near the smoke generating cell 2. However, as described above, the lid portion 6 as a heat insulating film exists between the other battery cells 2 other than the smoke generating cell 2 and the space above them. Therefore, the heat generated by the other battery cells 2 due to the heat of the discharge gas is prevented by the lid portion 6.

[0031] Therefore, in the battery module 1, not only is the lateral heat transfer between adjacent battery cells 2 suppressed by the heat insulating member 4, but also the heat transfer to other battery cells 2 through the space above the battery cell 2 is suppressed by the lid portion 6 as a heat insulating film, so that the continuous explosion of other battery cells 2 is suppressed. As described above, since the positive electrode terminal 23 and the negative electrode terminal 24 project from the upper surface portion 22, a slight gap is formed between the upper surface portion 22 and the lid portion 6. However, since the discharge gas has the property of escaping (flowing) upward, it is difficult for the discharge gas to flow into the gap. It is preferable that the casing of the battery pack is provided with a valve that opens when the internal pressure of the casing rises, and it is preferable that the discharge gas is exhausted from the battery pack when this valve opens.

[0032] [1-3. Effect] (1) According to the above-described battery module 1 and battery pack, when the safety valve 25 of the fuming cell 2 opens, a heat-insulating film for preventing deflagration is formed on the upper surface of the upper surface portion 22 of the other battery cells 2 by the exhaust gas of the fuming cell 2. Thereby, the transfer of the heat of the exhaust gas to the other battery cells 2 through the space above the battery cells 2 is suppressed. Therefore, deflagration of the other battery cells 2 can be prevented. Further, in the battery module 1, the heat-insulating film is formed only when the safety valve 25 opens. In other words, during normal operation of each battery cell 2, the heat dissipation of each battery cell 2 is not hindered by the heat-insulating film. Therefore, a decrease in the heat dissipation performance of the battery cell 2 can be prevented. Consequently, deterioration of the battery cell 2 (battery module 1 and battery pack) can be suppressed.

[0033] (2) On the upper surface portion 22 of each battery cell 2, not only the safety valve 25 but also the positive electrode terminal 23 and the negative electrode terminal 24 are provided. For this reason, if a member constituting the heat-insulating film is arranged on the upper surface portion 22, the structure of the battery module or the battery pack may become complicated. On the other hand, in the above-described battery module 1 and battery pack, since the member constituting the heat-insulating film is provided on the lid portion 6 of the case 3, a heat-insulating film can be formed during smoking with a simple configuration without being restricted by the arrangement of the positive electrode terminal 23 and the negative electrode terminal 24 of each battery cell 2.

[0034] (3) In the above-described battery module 1 and battery pack, the member constituting the heat-insulating film is the lid portion 6 of the case 3. In this way, by also using the lid portion 6 of the case 3 for accommodating each battery cell 2 as a member constituting the heat-insulating film, deflagration of the other battery cells 2 can be prevented without increasing the number of parts. Further, by using the lid portion 6 covering the plurality of battery cells 2 as a member constituting the heat-insulating film, the upper surfaces of the other battery cells 2 can be surely covered, and deflagration of the other battery cells 2 can be more surely prevented.

[0035] (4) When the support portion 61 is formed of a resin having a melting point lower than that of the portion other than the support portion 61 of the lid portion 6, the support portion 61 begins to melt before the temperature in the space between the battery cell 2 and the lid portion 6 reaches the melting temperature of the portion. Therefore, the support of the lid portion 6 by the support portion 61 can be released more reliably by a simple method, and the lid portion 6 can be dropped. Further, in this case, since the plate thickness of the support portion 61 can be made equal to that of the portion other than the support portion 61 of the lid portion 6, the lid portion 6 can be dropped during smoke generation while ensuring the rigidity strength of the lid portion 6.

[0036] (5) When the support portion 61 is formed thinner than the portion other than the support portion 61 of the lid portion 6, the lid portion 6 can be dropped by using the heat and momentum (pressure) during smoke generation with a simple configuration without changing the material of the lid portion 6. Further, by combining the above-described configuration methods of the support portion 61, the lid portion 6 can be dropped more quickly by using the heat and momentum (pressure) during smoke generation.

[0037] [2. Second Embodiment] FIG. 4 is a longitudinal sectional view showing a battery module 1' as a second embodiment. The battery module 1' is different from the battery module 1 of the first embodiment in that the members constituting the heat insulation film for preventing continuous explosion are different, and the support portion 61 and the smoke exhaust portion 62 are not provided in the case 3'. In the following description, the configuration different from the above-described first embodiment will be mainly described, and a dash (') will be added to the reference numerals in FIG. 1 for the configuration corresponding to the configuration of the first embodiment, and duplicate descriptions will be omitted. Although the illustration of the battery pack of the second embodiment is also omitted, similar to the first embodiment, a plurality of battery modules 1' are housed in a casing to be configured.

[0038] In the battery module 1' of the second embodiment, the members constituting the heat insulation film for preventing continuous explosion are the ceramic 11 and the thermosetting resin 12 provided on the lid portion 6' of the case 3'. In the battery module 1' and the battery pack of the second embodiment, when a part of the plurality of battery cells 2' generates heat and emits smoke, the ceramic 11 and the thermosetting resin 12 are scattered and fall by the released gas. Then, the thermosetting resin 12 is cured on the upper surface portion 22' of each battery cell 2' together with the ceramic 11 by the heat of the released gas, thereby forming a heat insulation film F (see FIG. 5) that prevents heat transfer between the space above each battery cell 2' and each battery cell 2'.

[0039] As shown in FIG. 4, the ceramic 11 and the thermosetting resin 12 are arranged as a package 8 enclosed in a film 7 on the surface of the lid portion 6' facing the battery cell 2' side, that is, on the lower surface. The ceramic 11 and the thermosetting resin 12 are provided, for example, as powders formed in fine particle form and mixed with each other, as enlarged and shown by a two-dot chain line in FIG. 4. The size of the particles is, for example, a diameter smaller than 1 mm (for example, 400 μm). The film 7 is made of a thin material that is easily dissolved by the released gas.

[0040] A plurality of packages 8 enclosing the ceramic 11 and the thermosetting resin 12 are provided. Further, the package 8 is preferably arranged at a position shifted from directly above the safety valve 25' of each battery cell 2'. Here, seven packages 8 arranged between adjacent battery cells 2' are exemplified, but the number of packages 8 is not limited to this. Also, the arrangement of the packages 8 is not limited to this. For example, the package 8 may be arranged at a position shifted in a direction perpendicular to the plane of the paper with respect to the position where the safety valve 25' of each battery cell 2' is provided.

[0041] The operation of the above-described battery module 1' will be described. When the smoke generating cell 2' generates smoke and the safety valve 25' of the smoke generating cell 2' opens, high-temperature exhaust gas jets out from the safety valve 25' of the smoke generating cell 2'. The film 7 of the plurality of packages 8 provided on the lid portion 6' is melted by the heat of the exhaust gas, and the powders of the ceramic 11 and the thermosetting resin 12 are exposed. Then, the ceramic 11 and the thermosetting resin 12 are scattered by the ejected exhaust gas.

[0042] Specifically, as shown by the dotted arrows in FIG. 5, the ceramic 11 and the thermosetting resin 12 are obliquely blown off and scattered by riding on the flow of the exhaust gas spreading around the safety valve 25' of the smoke generating cell 2'. In this embodiment, as described above, since the package 8 is not disposed directly above the smoke generating cell 2', the ceramic 11 and the thermosetting resin 12 are prevented from sticking to the lid portion 6' by the exhaust gas flowing upward from the safety valve 25' of the smoke generating cell 2'.

[0043] Thereafter, the scattered ceramic 11 and thermosetting resin 12 fall and adhere to the upper surface of the battery cell 2', and the thermosetting resin 12 cures together with the ceramic 11 by the heat and pressure of the exhaust gas. As a result, a heat insulating film F is formed on the upper surface portion 22' of the other battery cells 2'. Therefore, since heat transfer to the other battery cells 2' through the space above the battery cell 2' is suppressed by the heat insulating film F, consecutive explosions of the other battery cells 2' are suppressed.

[0044] In the above-described battery module 1' and battery pack, the same effects as those of the battery module 1 and battery pack of the first embodiment can be obtained. That is, according to the above-described battery module 1' and battery pack, when the safety valve 25' of the fuming cell 2' opens, a heat insulation film F for preventing continuous detonation is formed on the upper surface of the upper surface portion 22' of the other battery cells 2' by the discharged gas of the fuming cell 2'. Therefore, continuous detonation of the other battery cells 2' can be prevented. Further, in the battery module 1' and the battery pack, since the heat insulation film F is formed only when the safety valve 25' opens, a decrease in the heat dissipation performance of the battery cell 2' can be prevented. Furthermore, since the ceramic 11 and the thermosetting resin 12 constituting the heat insulation film F are provided on the lid portion 6', the heat insulation film F can be formed on the upper surface of each battery cell 2' with a simple configuration.

[0045] (6) Also, in the above-described battery module 1' and battery pack, the members constituting the heat insulation film F are the ceramic 11 and the thermosetting resin 12, and the ceramic 11 and the thermosetting resin 12 are arranged on the lower surface of the lid portion 6' as a package 8 enclosed in the film 7. In this way, since continuous detonation can be prevented only by attaching the package 8 to the lower surface of the lid portion 6', it is easy to apply to existing battery modules and battery packs, and the versatility can be enhanced. Further, since a plurality of packages 8 are provided in the battery module 1', it is possible to cope with the fuming of any of the plurality of battery cells 2'.

[0046] (7) By arranging the package 8 at a position shifted from directly above the safety valve 25' of each battery cell 2', it is possible to prevent the ceramic 11 and the thermosetting resin 12 contained in the package 8 from sticking to the lid portion 6' by the momentum of the discharged gas. Also, in this case, the ceramic 11 and the thermosetting resin 12 ride on the flow of the discharged gas spreading around the safety valve 25' of the fuming cell 2' and are blown obliquely and fall. Therefore, it is possible to suppress the local accumulation of the ceramic 11 and the thermosetting resin 12 on the upper surface of the other battery cells 2'. Thus, the heat insulation film F can be uniformly formed on the upper surface of the other battery cells 2'.

[0047] [3. Others] The configurations of the above-described battery modules 1, 1' and the battery pack are merely examples. The battery pack does not necessarily include a plurality of the above-described battery modules 1, 1'. In this case, each battery cell 2, 2' may be directly placed on a casing forming the outer shell of the battery pack. Also, in this case, the configuration of the case 3, 3' may be applied to the casing. That is, the "battery module" in the claims is what is intended (for convenience) to be "a plurality of battery cells arranged side by side in the lateral direction via a heat insulating member and housed in a battery case", and the "battery module" itself may be read as the "battery pack".

[0048] Each battery cell 2, 2' is not limited to a rectangular shape as long as it is a battery having safety valves 25, 25' on its upper surface portions 22, 22'. The shape of the case 3, 3' is not limited to a rectangular housing as long as it can arrange a plurality of battery cells 2, 2' side by side in the lateral direction. In the battery module 1 of the first embodiment, the lid portion 6 is not limited to the above-described one as long as the support portion 61 can first melt and drop when smoke is emitted from the battery cell 2. For example, the lid portion 6 may be externally fitted to the side wall portion 52 of the tray portion 5. In this case, the support portion 61 may be provided at a position on the inner side of the outer peripheral portion of the lid portion 6 that does not overlap with the side wall portion 52 in the lateral direction (a position where the inner portion of the support portion 61 on the lid portion 6 drops when the support portion 61 melts).

[0049] The configuration of the lid portion 6 of the first embodiment may be applied to the battery module 1' of the second embodiment. In this case, since a double heat insulation film is formed on the battery module 1' by the heat insulation film F formed of the ceramic 11 and the thermosetting resin 12 enclosed in the packaging body 8 and the heat insulation film formed by the lid portion 6', the heat insulation property of the heat insulation film is further improved. In particular, in the battery module 1' of the second embodiment, since the heat insulation film F is formed by the scattered ceramic 11 and thermosetting resin 12, it is difficult to accurately control the shape and position of the heat insulation film F. On the other hand, in the battery module 1 of the first embodiment, since the heat insulation film is formed by the lid portion 6 that falls by its own weight, the shape and position of the heat insulation film can be controlled more accurately. Therefore, by applying the configuration disclosed in the first embodiment to the battery module 1' of the second embodiment, the heat insulation property of the heat insulation film can be further improved.

[0050] Also, the lid portion 6' of the second embodiment may be provided with the smoke exhaust portion 62 of the first embodiment. The lid portion 6' of the second embodiment may be provided with a smoke exhaust mechanism including a hose that communicates the inside and the outside of the case 3'. Further, the battery modules 1, 1' are not limited to the vehicle driving battery, and may be applied to various battery modules and battery packs including a plurality of battery cells.

Explanation of reference numerals

[0051] 1, 1' Battery module 2, 2' Battery cell 3, 3' Case (battery case) 4, 4' Heat insulation member 6, 6' Lid portion 7 Film 8 Packaging body 11 Ceramic 12 Thermosetting resin 22, 22' Upper surface portion 25, 25' Safety valve 61 Support portion 62 Smoke exhaust portion 62h Smoke exhaust port F Heat insulation film

Claims

1. In a battery module in which a plurality of battery cells arranged side by side in the lateral direction are housed in a battery case via a heat insulating member, on the upper surface of each of the battery cells, a safety valve is provided for discharging the gas in each battery cell by opening the valve due to an increase in the internal pressure of each battery cell, among the plurality of battery cells, when the safety valve of any one of the battery cells opens, a heat insulating film for preventing continuous detonation is formed on the upper surface of the other battery cells other than the battery cell in which the safety valve has opened by the discharged gas of the battery cell in which the safety valve has opened, the battery case includes a lid portion that covers the plurality of battery cells above the upper surfaces of the plurality of battery cells, the member constituting the heat insulating film is provided on the lid portion, the heat insulating film is formed by the member falling onto the upper surfaces of the plurality of battery cells due to the discharged gas. A battery module characterized by the above.

2. the member is the lid portion, the lid portion includes a support portion provided at a position that does not overlap with the side wall portion of the battery case on the outer peripheral portion of the battery case to support the lid portion, and a smoke exhaust portion provided directly above the safety valve of each battery cell, the lid portion forms a smoke exhaust port for discharging the discharged gas to the outside of the battery case by the support portion first melting and falling due to the discharged gas, and then the smoke exhaust portion directly above the battery cell in which the safety valve has opened melting next, thereby forming the heat insulating film. The battery module according to claim 1, characterized by the above.

3. the support portion is formed of a resin having a lower melting point than the other portions of the lid portion. The battery module according to claim 2, characterized by the above.

4. the support portion is formed thinner than the other portions of the lid portion. The battery module according to claim 2 or 3, characterized in that

5. On the surface of the lid portion facing the battery cell side, a plurality of packages are provided in which a ceramic and a thermosetting resin are both encapsulated in a film that is easily dissolved by the released gas. The member is the ceramic and the thermosetting resin. The battery module according to any one of claims 1 to 4, characterized in that

6. The package is arranged at a position shifted from directly above the safety valve of each battery cell. The battery module according to claim 5, characterized in that

7. A battery pack comprising a plurality of battery modules according to any one of claims 1 to 6. Characterized in that

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