Battery module

Abstract

To provide a battery module capable of suppressing inflammation or combustion of a gas caused by a substance which is leaked from a cell.SOLUTION: A battery module 1 comprises a plurality of cells 3 and the battery module 1 has a first sidewall 11 and a second sidewall 12 which are opposed and comprises a storage section 10 for the cells 3, a fire-fighting gas exhaust section 20, a gas exhaust section 30 capable of exhausting a gas caused by a substance which is leaked from the cell 3, and air exhaust section 40. The gas has a different specific gravity from air, the gas exhaust section 30 is disposed on any one of or both the first sidewall 11 and the second sidewall 12, the air exhaust section 40 is disposed on any one of or both the first sidewall 11 and the second sidewall 12, the air exhaust section 40 and the gas exhaust section 30 are disposed at positions which are different from each other in a vertical direction, and the fire-fighting gas exhaust section 20 is disposed between the first sidewall 11 and the second sidewall 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery module. [Background technology]

[0002] Conventionally, there has been known a leak test device (hereinafter referred to as a leak test device) for an electrochemical energy accumulator that uses a sensor to detect the gas concentration of volatile components (electrolyte vapor, electrolyte gas) of an electrolyte leaked from an electrochemical energy accumulator (lithium ion battery) and releases or stops a binder depending on the detected gas concentration (for example, Patent Document 1).The leak test device described in Patent Document 1 is designed to release a binder when the gas concentration increases due to electrolyte leakage in an individual battery cell, thereby causing the binder to absorb the leaked electrolyte and suppressing electrolyte leakage from the battery housing (battery pack, battery module). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2014-512004 Summary of the Invention [Problem to be solved by the invention]

[0004] In the leak test device described in Patent Document 1, the binder that absorbs the electrolyte leaked from the lithium-ion battery remains inside the battery module. However, because the electrolyte in lithium-ion batteries uses a volatile, flammable liquid such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate, there is a concern that if an ignition source comes close to the electrolyte gas or the binder that has absorbed the electrolyte, it may ignite and burn due to the air inside the battery module.

[0005] Therefore, the present invention aims to provide a battery module that can appropriately discharge the air within the battery module and gases resulting from substances leaked from the cells, remove combustion-supporting materials and combustible materials (flammable gases), and release fire-extinguishing gas at the appropriate time to prevent ignition or combustion of electrolyte gas or electrolyte. [Means for solving the problem]

[0006] (1) The battery module of the present invention, which is provided to solve the above-mentioned problems, is a battery module having at least one cell, and has at least a first side wall and a second side wall facing each other, and is equipped with: a storage section for accommodating the cell; a fire extinguishing gas discharge section for discharging fire extinguishing gas toward the inside of the storage section; a gas exhaust section capable of discharging gas resulting from a substance leaked from the cell; and an air exhaust section capable of discharging air, wherein the gas has a specific gravity different from that of air; at least one gas exhaust section is disposed on either or both of the first side wall and the second side wall; and at least one air exhaust section is disposed on either or both of the first side wall and the second side wall; the air exhaust section and the gas exhaust section are disposed at different positions in the vertical direction; and the fire extinguishing gas discharge section is disposed between the first side wall and the second side wall.

[0007] The battery module of the present invention includes a gas exhaust section and an air exhaust section, with at least one gas exhaust section disposed on either one or both of the first side wall and the second side wall of the housing section, and at least one air exhaust section disposed on either one or both of the first side wall and the second side wall. Furthermore, in the battery module of the present invention, the air exhaust section and the gas exhaust section are disposed at different positions in the vertical direction. Furthermore, in the battery module of the present invention, gas resulting from substances leaking from the cells (hereinafter simply referred to as gas) has a specific gravity different from that of air. Therefore, in the battery module of the present invention, the gas and air are separated based on their specific gravities, and the gas is discharged to the outside of the housing section (battery module) via the gas exhaust section, and the air is discharged to the outside of the housing section via the air exhaust section. That is, the battery module of the present invention can separate the gas and the air and discharge them to the outside of the battery module (housing section).

[0008] Here, when the battery module is a lithium-ion battery, the gas may be, for example, a volatile gas with a higher specific gravity than air, such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate, which is derived from an electrolyte solution. When the battery module is a fuel cell that uses hydrogen as fuel, the gas may be, for example, hydrogen gas, which has a lower specific gravity than air. Therefore, when the battery module is a lithium-ion battery, gases with a higher specific gravity than air (such as dimethyl carbonate) accumulate in the lower part of the storage unit, so it is preferable to position the gas exhaust unit lower than the air exhaust unit. On the other hand, when the battery module is a fuel cell that uses hydrogen as fuel, gases with a lower specific gravity than air (such as hydrogen gas) accumulate in the upper part of the storage unit, so it is preferable to position the gas exhaust unit higher than the air exhaust unit.

[0009] Furthermore, in the battery module of the present invention, a fire extinguishing gas discharge section is disposed between the first side wall and the second side wall, so that the fire extinguishing gas discharged from the fire extinguishing gas discharge section can push gas resulting from substances leaking from the cells toward the gas discharge section and can also push air toward the air discharge section. Furthermore, a fire extinguishing gas layer can be formed between the air layer and the gas layer, preventing the gas and air from mixing. As a result, the battery module of the present invention can effectively prevent ignition and combustion of the electrolyte gas.

[0010] (2) The battery module of the present invention described above may be characterized by comprising a control device and a gas detection sensor that detects the gas, and the control device controls the fire extinguishing gas discharge unit to discharge the fire extinguishing gas on the condition that the gas concentration detected by the gas detection sensor is equal to or higher than a predetermined concentration.

[0011] The battery module of the present invention, configured as described above in (2), can release fire extinguishing gas at an appropriate timing, thereby preventing the gas from mixing with air before the gas fills the storage section.

[0012] (3) The battery module of the present invention described above may be characterized in that the fire extinguishing gas is an inert gas having a specific gravity greater than that of air but less than that of the gas.

[0013] By configuring the battery module of the present invention as described above in (3), a fire-extinguishing gas layer can be reliably formed between the air layer above the storage section and the gas layer below the storage section, thereby effectively suppressing ignition and combustion of the gas. Furthermore, the battery module of the present invention can use the fire-extinguishing gas to push air out of the storage section through the air outlet and also push gas out of the storage section through the gas outlet, thereby effectively suppressing ignition and combustion of the gas. Examples of inert gas include nitrogen and argon, but it is preferable to use argon, which has a higher specific gravity than air.

[0014] (4) In the battery module of the present invention described above, the storage section may accommodate a plurality of the cells, and a gas passage may be provided between the plurality of cells.

[0015] The battery module of the present invention, configured as described above in (4), can efficiently exhaust gas inside the battery module through the ventilation paths provided between the multiple cells. Furthermore, the battery module of the present invention can distribute and flow the fire extinguishing gas through the ventilation paths, preventing the fire extinguishing gas from directly hitting the cells (battery cells). This allows the battery module of the present invention to prevent damage to the cells.

[0016] (5) The battery module of the present invention described above may be characterized in that at least one pair of the gas exhaust sections are arranged diagonally opposite each other in the storage section, and at least one pair of the air exhaust sections are arranged diagonally opposite each other in the storage section.

[0017] In the battery module of the present invention, the gas exhaust units are arranged diagonally in the housing, allowing gas to be exhausted through the gas exhaust units before it is agitated by convection. Furthermore, in the battery module of the present invention, the air exhaust units are arranged diagonally in the housing, allowing air to be exhausted through the air exhaust units before it is agitated by convection. As a result, the battery module of the present invention allows gas and air to be exhausted to the outside of the housing while maintaining their respective layers, effectively preventing the gas and air from mixing. Therefore, the battery module of the present invention effectively prevents the gas from igniting or burning.

[0018] (6) The battery module of the present invention described above may be characterized in that the fire extinguishing gas discharge portions are provided in pairs in the vertical direction so as to face each other.

[0019] By configuring the battery module of the present invention as described above in (6), the released fire extinguishing gas collides with each other near the vertical center and spreads horizontally, thereby covering the gas with the fire extinguishing gas. In other words, the battery module of the present invention can form a fire extinguishing gas layer between the gas layer and the air layer. This prevents the gas from mixing with the air layer above, effectively preventing ignition or combustion of the gas. Here, it is desirable to position the fire extinguishing gas release section, for example, near the center of the storage section (between the first side wall and the second side wall) in order to evenly release the fire extinguishing gas into the storage section.

[0020] (7) In the battery module of the present invention described above, the control device may be characterized in that it calculates a predicted gas concentration after a predetermined time has elapsed in the case where the gas concentration detected by the gas detection sensor is less than the predetermined concentration and the fire extinguishing gas is released based on the average rate of increase in the gas concentration per predetermined time, and controls the release of the fire extinguishing gas on the condition that it is determined that the predicted gas concentration will increase above the current gas concentration.

[0021] By configuring the battery module of the present invention as described above in (7), it is possible to release fire extinguishing gas even when the gas concentration is below a predetermined concentration if it is determined that the predicted gas concentration that would result from releasing fire extinguishing gas will be higher than the current gas concentration. That is, even when the gas concentration is below a predetermined concentration, the battery module of the present invention can predictively release fire extinguishing gas when it is determined that the average gas concentration is increasing at a fast rate and that it will be difficult to keep the gas concentration below the predetermined concentration even if fire extinguishing gas is released after the fact. As a result, the battery module of the present invention can prevent the gas from filling the storage compartment even when the gas leakage rate is fast, thereby effectively preventing ignition or combustion of the gas.

[0022] (8) The battery module of the present invention described above may be characterized in that the gas detection sensor is disposed on the bottom side of the housing portion.

[0023] The battery module of the present invention, configured as described above in (8), can quickly detect gas that has a high specific gravity and tends to accumulate at the bottom of the storage section. As a result, the battery module of the present invention can detect gas leakage before the storage section is filled with gas, thereby effectively preventing the gas from igniting or burning.

[0024] (9) The battery module of the present invention described above may be characterized by comprising a control device and a gas detection sensor that detects the gas, wherein the gas exhaust section and the air exhaust section are configured to be openable and closable and are normally closed, and the control device controls to open the gas exhaust section and the air exhaust section and to release the fire extinguishing gas, on the condition that the gas concentration detected by the gas detection sensor is equal to or higher than a predetermined concentration, and controls to stop the release of the fire extinguishing gas and to close the gas exhaust section and the air exhaust section, on the condition that the gas concentration is lower than the predetermined concentration.

[0025] The battery module of the present invention, configured as described above in (9), can prevent the gas and air from convecting within the storage section and mixing with each other. Furthermore, since the gas exhaust section and air exhaust section of the battery module of the present invention are normally closed, the gas concentration can be detected before the gas is discharged (exhausted) from the storage section. This allows the battery module of the present invention to quickly detect an increase in gas concentration with the gas detection sensor, thereby more effectively preventing the gas from igniting or burning. [Effects of the Invention]

[0026] According to the present invention, a battery module can be provided that can properly discharge the air within the battery module and gas caused by substances leaked from the cells, remove combustion materials and flammable materials (flammable gases), and can suppress the ignition and combustion of gas by releasing fire-extinguishing gas at the appropriate time. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic overall perspective view of an embodiment of a battery module of the present invention; [Figure 2] 1 is a schematic front view of a battery module according to an embodiment of the present invention; [Figure 3] 1 is a partially omitted top view showing an embodiment of a cell arrangement in a battery module of the present invention. FIG. [Figure 4] FIG. 4 is an explanatory diagram showing an example of a condition for releasing a fire extinguishing gas in the battery module of the present invention. [Figure 5] FIG. 4 is a flow chart for determining the gas concentration in the battery module of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] A battery module 1 according to one embodiment of the present invention will be described in detail below with reference to the drawings. Note that each drawing is a schematic representation for ease of understanding, and may differ from the actual shape, size, and arrangement of components. Also, note that in Figure 3, the control device 7, gas detection sensor 5, etc. are omitted.

[0029] 1 and 2, a battery module 1 of the present invention has at least one (a plurality of in this embodiment) cell 3 (also referred to as battery cell 3). The plurality of cells 3 are connected, for example, in parallel or series. The plurality of cells 3 are housed in a housing 10, which will be described later.

[0030] In this embodiment, the cells 3 are configured as lithium-ion batteries, and a substance such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is used as the electrolyte. Here, the electrolyte generates a gas (vapor) having a specific gravity greater than that of air when volatilized (vaporized). That is, in the battery module 1 of the present invention, a gas such as dimethyl carbonate having a specific gravity greater than that of air may be generated due to a substance (electrolyte in this embodiment) leaking from the cell 3 due to, for example, expansion of the cell 3. In other words, in the battery module 1 of the present invention, the gas has a specific gravity different from that of air. In the battery module 1 of the present invention, the following configuration is configured to prevent the gas and air from mixing, and to effectively prevent the gas from igniting or burning by using a fire extinguishing gas.

[0031] The battery module 1 includes a housing portion 10 that houses the cells 3, a fire extinguishing gas discharge portion 20, a gas exhaust portion 30, an air exhaust portion 40, a gas detection sensor 5, a control device 7, and the like.

[0032] In this embodiment, the storage section 10 is formed in a rectangular parallelepiped shape and can store the cells 3. Furthermore, as shown in FIG. 3 , in this embodiment, gas ventilation paths 18 are provided between the multiple cells 3. The ventilation paths 18 are formed between each cell 3 and between each cell 3 and the storage section 10. Therefore, the gas passes through the ventilation paths 18 and is smoothly discharged from the gas discharge section 30, which will be described later.

[0033] As shown in Figures 1 and 2, the storage unit 10 has a first side wall 11 and a second side wall 12 that face each other. In addition to the above, the storage unit 10 has a third side wall 13, a fourth side wall 14, an upper wall 15, a bottom wall 16, etc. The storage unit 10 is made of an appropriate insulating material. Furthermore, the storage unit 10 is configured so that, for example, the upper wall 15 is detachable, and the cells 3 can be stored in the storage unit 10 from above. After the cells 3 are stored in the storage unit 10, the storage unit 10 is sealed by the upper wall 15.

[0034] The first side wall 11 is erected on one end side (left side in the figure) in the left-right direction of the bottom wall 16. The first side wall 11 is provided with a gas exhaust section 30 and an air exhaust section 40, which will be described later. In the following description, the gas exhaust section 30 provided on the first side wall 11 will also be referred to as a first gas exhaust section 30A, and the air exhaust section 40 provided on the first side wall 11 will also be referred to as a first air exhaust section 40A. The first gas exhaust section 30A is disposed on one end side in the width direction (rear side in the figure) at the lower end side of the first side wall 11. The first air exhaust section 40A is disposed on the other end side in the width direction (front side in the figure) at the upper end side of the first side wall 11. In other words, the first air exhaust section 40A and the first gas exhaust section 30A are disposed at different positions in the up-down direction.

[0035] The second side wall 12 is erected on the other end side in the left-right direction of the bottom wall 16 (the right side in the figure) and is disposed opposite the first side wall 11 with a gap therebetween. The second side wall 12 is provided with a gas discharge section 30 and an air discharge section 40, which will be described later. In the following description, the gas discharge section 30 provided on the second side wall 12 will also be referred to as a second gas discharge section 30B, and the air discharge section 40 provided on the second side wall 12 will also be referred to as a second air discharge section 40B. The second gas discharge section 30B is disposed on one end side in the width direction (the front side in the figure) at the lower end side of the second side wall 12. The second air discharge section 40B is disposed on the other end side in the width direction (the rear side in the figure) at the upper end side of the second side wall 12. That is, the second air discharge section 40B and the second gas discharge section 30B are disposed at different positions in the up-down direction. Furthermore, the first gas discharge section 30A and the second gas discharge section 30B (a pair of gas discharge sections 30, 30) are arranged diagonally from each other in the storage section 10. Furthermore, the first air discharge section 40A and the second air discharge section 40B (a pair of air discharge sections 40, 40) are arranged diagonally from each other in the storage section 10. Note that the first gas discharge section 30A and the second gas discharge section 30B, and the first air discharge section 40A and the second air discharge section 40B can also be arranged to face each other.

[0036] The gas exhaust unit 30 is configured to exhaust gas resulting from substances (such as electrolyte) leaked from the cells 3 to the outside of the storage unit 10 (battery module 1). As shown in FIG. 2, the gas exhaust unit 30 is provided with an open / close door 31. The gas exhaust unit 30 can switch between an open state, which connects the storage unit 10 to the outside, and a closed state, which closes the gas exhaust unit 30, by opening and closing the open / close door 31 under the control of a control device 7 (described later). Note that an open / close valve or the like may be provided instead of the open / close door 31. As will be described in detail later, the gas exhaust unit 30 is normally closed and is opened when the gas concentration Cd reaches a predetermined concentration. As shown in FIG. 2, the gas exhaust unit 30 can exhaust gas separated from air due to the difference in specific gravity to the outside of the storage unit 10.

[0037] The air exhaust unit 40 is configured to exhaust air from within the storage unit 10 (battery module 1) to the outside. The air exhaust unit 40 is provided with an open / close door 41. The air exhaust unit 40 can switch between an open state, which connects the storage unit 10 to the outside, and a closed state, which closes the air exhaust unit 40, by opening and closing the open / close door 41 under the control of a control device 7 (described later). Note that an open / close valve or the like may be provided instead of the open / close door 41. As will be described in detail later, the air exhaust unit 40 is normally closed and is opened when the gas concentration Cd reaches a predetermined concentration. The air exhaust unit 40 can exhaust air separated from the gas due to the difference in specific gravity to the outside of the storage unit 10. This prevents the gas and air (oxygen) from mixing, thereby preventing the gas from igniting or burning.

[0038] As shown in FIGS. 1 and 2, a plurality of gas detection sensors 5 are provided on the bottom wall 16 of the storage unit 10. The gas detection sensors 5 are arranged on the bottom side of the cells 3, and in this embodiment, are arranged along the width direction (left-right direction in the figure) of the storage unit 10, near the center in the depth direction of the storage unit 10. The gas detection sensors 5 can detect the presence or absence of gas as well as the gas concentration Cd. The gas detection sensors 5 are connected to the control device 7, and data on the presence or absence of gas and the gas concentration Cd detected by the gas detection sensors 5 is sent to the control device 7 and can be used for controlling the control device 7. Various sensors can be used for the gas detection sensors 5. Note that if the gas has a specific gravity smaller than that of air, it is preferable to provide the gas detection sensors 5 on the upper side of the storage unit 10.

[0039] The extinguishing gas discharge section 20 discharges extinguishing gas toward the interior of the storage section 10. The extinguishing gas discharge section 20 is disposed between the first side wall 11 and the second side wall 12. From the viewpoint of discharging extinguishing gas evenly into the storage section 10, the extinguishing gas discharge section 20 is preferably disposed near the center of the first side wall 11 and the second side wall 12 and near the center of the third side wall 13 and the fourth side wall 14. A pair of extinguishing gas discharge sections 20 are disposed facing each other in the vertical direction, with one disposed on the top wall 15 and one disposed on the bottom wall 16. Therefore, the pair of extinguishing gas discharge sections 20 can discharge extinguishing gas toward the center of the storage section 10. Since the extinguishing gas discharge sections 20 have the same configuration, only one of the extinguishing gas discharge sections 20 will be described below unless there is a need to distinguish between them.

[0040] The extinguishing gas discharge section 20 is provided with an appropriate on-off valve (not shown), which is connected to the control device 7. Therefore, under the control of the control device 7, the extinguishing gas discharge section 20 can be freely switched between an open state in which the extinguishing gas is discharged and a closed state in which the extinguishing gas discharge section 20 is closed. As will be described in detail later, under the control of the control device 7, the extinguishing gas discharge section 20 is controlled to discharge the extinguishing gas on the condition that the gas concentration Cd detected by the gas detection sensor 5 is equal to or higher than a predetermined concentration.

[0041] Here, the extinguishing gas is preferably an inert gas having a specific gravity greater than that of air but less than that of gas. For example, the extinguishing gas may be carbon dioxide, IG-541 (52% nitrogen, 40% argon, 8% carbon dioxide), IG-55 (50% nitrogen, 50% argon), or nitrogen. Since nitrogen has a specific gravity almost the same as air, if the gas has a specific gravity greater than that of air, it is desirable to use an extinguishing gas other than nitrogen that has a specific gravity greater than that of air, such as carbon dioxide, IG-541, or IG-55, from the viewpoint of separating the gas from air. If the gas has a specific gravity less than that of air, it is desirable to use an extinguishing gas such as helium, from the viewpoint of separating the gas from air.

[0042] As shown in Figure 2, when extinguishing gas is released from a pair of extinguishing gas release sections 20, 20, the extinguishing gases collide with each other from above and below, forming an extinguishing gas layer in the middle of the storage section 10 in the vertical direction, and the gas and air are pushed out toward the gas discharge section 30 and the air discharge section 40 and discharged.

[0043] The control device 7 is configured with, for example, a microcomputer, etc. The control device 7 can perform various controls related to the battery module 1, such as controls related to the opening and closing of the gas discharge section 30, the air discharge section 40, and the fire extinguishing gas discharge section 20, and calculations related to the gas concentration Cd detected by the gas detection sensor 5.

[0044] Here, the control device 7 controls the gas discharge section 30 and the air discharge section 40, which are in a closed state, to open and controls the release of fire extinguishing gas, provided that the gas concentration Cd detected by the gas detection sensor 5 is equal to or greater than a predetermined concentration (for example, 50% of the lower flammable limit concentration Ce).It is preferable that the control device 7 controls the gas discharge section 30 and the air discharge section 40 to stop the release of fire extinguishing gas and closes the gas discharge section 30 and the air discharge section 40, provided that the gas concentration Cd falls below a predetermined concentration (50% of the lower flammable limit concentration Ce).

[0045] Here, for example, even if the gas concentration Cd is below 50% of the lower flammability limit Ce, if the average concentration increase rate A of the gas concentration Cd is fast, there is a concern that the increase in the gas concentration Cd cannot be suppressed even if the extinguishing gas is released after the lower flammability limit Ce reaches 50% or more. Therefore, after extensive research, the inventors of the present invention have come to the conclusion that even if the lower flammability limit Ce is below 50%, an unintended increase in the gas concentration Cd can be suppressed by releasing the extinguishing gas in advance at a predetermined timing. Below, the details of the control related to the predicted release of the extinguishing gas described above will be explained with reference to FIG. 4.

[0046] FIG. 4 is a graph showing the relationship between the slope of the predicted gas concentration change and time (t). where: Ce: Lower flammability limit concentration [vol%], Cd: Gas concentration, detected concentration [vol%], A: Average concentration increase rate [vol% / sec] Vbat: Storage compartment (battery module) space volume [L] B: Fire extinguishing gas release rate [L / sec] t: time [t] It is said that...

[0047] The relationship between the predicted gas concentration (after t seconds) under fire extinguishing gas release and the current gas concentration Cd (detected concentration Cd) is expressed by the following equation 1. {(Cd+A*t)*Vbat} / (B*t+Vbat)≧Cd (Formula 1) The gradient of the predicted gas concentration change is expressed by the following equation 2: (Cd*B-Vbat*A)*t≦0 (Formula 2)

[0048] Therefore, the increase in gas concentration Cd can be suppressed by controlling the release of extinguishing gas so as to satisfy the above formula 2, which corresponds to the lower region of Figure 4. Therefore, the control device 7 may calculate a predicted gas concentration after a predetermined time has elapsed in the case where the gas concentration Cd detected by the gas detection sensor 5 is less than a predetermined concentration and the extinguishing gas is released based on the average gas concentration increase rate A per predetermined time, and control the release of extinguishing gas on the condition that the predicted gas concentration is determined to be higher than the current gas concentration Cd.

[0049] The above is the configuration of the battery module 1 of the present invention. Next, based on the flow chart of Figure 5, a detailed description will be given below of one embodiment of a method for determining the gas concentration of the battery module 1 and a method for controlling the release of fire-extinguishing gas based on the gas concentration determination.

[0050] 5, when gas concentration determination is started in the battery module 1, it is determined whether or not the gas concentration Cd satisfies Condition 1 (Cd≧½Ce) (step S1: first gas concentration determination step). In step S1, it is determined whether or not the gas concentration Cd is equal to or greater than ½ (50%) of the lower flammable concentration Ce.

[0051] In step S1, if the gas concentration Cd is equal to or less than half the lower flammability limit concentration Ce, it is determined whether the average concentration increase rate A satisfies condition 2 (A≧Cd*B / Vbat) (step S2: gas concentration increase prediction determination step). In step S2, if the average concentration increase rate A does not satisfy condition 2, the process returns to step S1.

[0052] In step S1, if the gas concentration Cd satisfies condition 1 (if the gas concentration Cd is equal to or greater than half the lower flammability limit concentration Ce), it is determined whether the gas discharge unit 30 and the air discharge unit 40 are open (step S3: discharge unit open / close determination step).In step S2, if the average concentration increase rate A satisfies condition 2, the discharge unit open / close determination step of step S3 is also executed.

[0053] In step S3, if the gas discharge part 30 and the air discharge part 40 are in a closed state, control is performed so that the gas discharge part 30 and the air discharge part 40 are opened to an open state (step S4: discharge part opening step).

[0054] In step S3, if the gas discharge section 30 and the air discharge section 40 are in the open state, control is performed to open the fire extinguishing gas discharge section 20 so as to discharge the fire extinguishing gas (step S5: fire extinguishing gas discharge step). Even if the discharge section opening step is performed in step S4, the process proceeds to step S5, and the discharge of the fire extinguishing gas is performed.

[0055] Next, it is determined whether the gas concentration Cd satisfies Condition 3 (Cd<1 / 10Ce) (Step S6: second gas concentration determination step). In Step S6, it is determined whether the gas concentration Cd is less than 1 / 10 of the lower flammable limit concentration Ce.

[0056] In step S6, if the gas concentration Cd satisfies condition 3, control is executed to stop the release of the extinguishing gas (step S7: extinguishing gas release stop step). In step S6, if the gas concentration Cd does not satisfy condition 3, the process returns to step S6.

[0057] In step S7, when the discharge of the fire extinguishing gas stops, the gas discharge part 30 and the air discharge part 40 are controlled to be blocked and in a closed state (step S8: discharge part blocking step). After step S8 is executed, the process returns to step S1 again or ends.

[0058] The above is an embodiment of the gas concentration determination method and the fire extinguishing gas release control method based on the gas concentration determination in the battery module 1 of the present invention. Next, the effects achieved by the battery module 1 of the present invention will be described below.

[0059] The battery module 1 of the present invention has the following configurations (a) to (i), and thereby can achieve unique effects.

[0060] (a) The battery module 1 of the present invention is a battery module 1 having at least one cell 3, and has at least a first side wall 11 and a second side wall 12 facing each other, and is equipped with a storage section 10 that stores the cell 3, a fire extinguishing gas discharge section 20 that discharges fire extinguishing gas toward the inside of the storage section 10, a gas discharge section 30 that can discharge gas caused by substances leaked from the cell 3, and an air discharge section 40 that can discharge air, wherein the gas has a specific gravity different from that of air, at least one gas discharge section 30 is arranged on either or both of the first side wall 11 and the second side wall 12, and at least one air discharge section 40 is arranged on either or both of the first side wall 11 and the second side wall 12, the air discharge section 40 and the gas discharge section 30 are arranged at different positions in the vertical direction, and the fire extinguishing gas discharge section 20 is arranged between the first side wall 11 and the second side wall 12.

[0061] The battery module 1 of the present invention includes a gas discharge section 30 and an air discharge section 40, with at least one gas discharge section 30 disposed on either or both of the first side wall 11 and the second side wall 12 of the storage section 10, and at least one air discharge section 40 disposed on either or both of the first side wall 11 and the second side wall 12. Furthermore, in the battery module 1 of the present invention, the air discharge section 40 and the gas discharge section 30 are disposed at different positions in the vertical direction. Furthermore, in the battery module 1 of the present invention, gas resulting from substances leaking from the cells 3 (hereinafter simply referred to as gas) has a specific gravity different from that of air. Therefore, in the battery module 1 of the present invention, the gas and air are separated based on their specific gravities, and the gas is discharged to the outside of the storage section 10 (battery module 1) via the gas discharge section 30, and the air is discharged to the outside of the storage section 10 via the air discharge section 40. In other words, the battery module 1 of the present invention can separate the gas and the air and discharge them to the outside of the battery module 1 (storage section 10).

[0062] Here, when the battery module 1 is a lithium ion battery, the gas may be, for example, a volatile gas with a specific gravity greater than that of air, such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate, which is derived from an electrolyte solution. When the battery module 1 is a fuel cell that uses hydrogen as fuel, the gas may be, for example, hydrogen gas, which has a specific gravity less than that of air. Therefore, when the battery module 1 is a lithium ion battery, gases with a specific gravity greater than that of air (such as dimethyl carbonate) accumulate in the lower part of the storage unit 10, so it is preferable to position the gas discharge unit 30 lower than the air discharge unit 40. On the other hand, when the battery module 1 is a fuel cell that uses hydrogen as fuel, gases with a specific gravity less than that of air (such as hydrogen gas) accumulate in the upper part of the storage unit 10, so it is preferable to position the gas discharge unit 30 higher than the air discharge unit 40.

[0063] Furthermore, in the battery module 1 of the present invention, the fire extinguishing gas discharge section 20 is disposed between the first side wall 11 and the second side wall 12, so that the fire extinguishing gas discharged from the fire extinguishing gas discharge section 20 can push gas resulting from substances leaking from the cells 3 toward the gas discharge section 30 and can also push air toward the air discharge section 40. Furthermore, since a fire extinguishing gas layer can be formed between the air layer and the gas layer, mixing of the gas and air can be suppressed. As a result, the battery module 1 of the present invention can effectively suppress ignition and combustion of the electrolyte gas.

[0064] (b) The battery module 1 of the present invention comprises a control device 7 and a gas detection sensor 5 that detects the gas, and the control device 7 controls the fire extinguishing gas discharge section 20 to discharge the fire extinguishing gas on the condition that the gas concentration Cd detected by the gas detection sensor 5 is equal to or higher than a predetermined concentration.

[0065] The battery module 1 of the present invention, configured as described above in (b), can release fire-extinguishing gas at an appropriate timing, thereby preventing the gas from mixing with air before the gas fills the storage section 10.

[0066] (c) The battery module 1 of the present invention is characterized in that the fire extinguishing gas is an inert gas having a specific gravity greater than that of air but smaller than that of the gas.

[0067] By configuring the battery module 1 of the present invention as described above in (c), a fire-extinguishing gas layer can be reliably formed between the air layer above the storage section 10 and the gas layer below the storage section 10, thereby effectively suppressing ignition and combustion of the gas. Furthermore, the battery module 1 of the present invention can use the fire-extinguishing gas to push air out of the storage section 10 through the air outlet 40 and push gas out of the storage section 10 through the gas outlet 30, thereby effectively suppressing ignition and combustion of the gas. Examples of inert gas include nitrogen and argon, but it is preferable to use argon, which has a higher specific gravity than air.

[0068] (d) The battery module 1 of the present invention is characterized in that a plurality of cells 3 are housed in the housing portion 10, and a gas ventilation path 18 is provided between the plurality of cells 3.

[0069] By configuring the battery module 1 of the present invention as described above in (d), gas inside the battery module 1 can be efficiently exhausted through the ventilation paths 18 provided between the multiple cells 3. Furthermore, the battery module 1 of the present invention can distribute and flow the fire extinguishing gas through the ventilation paths 18, thereby preventing the fire extinguishing gas from directly hitting the cells 3 (battery cells 3). As a result, the battery module 1 of the present invention can prevent damage to the cells 3.

[0070] (e) The battery module 1 of the present invention is characterized in that at least one pair of gas exhaust sections 30 are arranged diagonally from each other in the storage section 10, and at least one pair of air exhaust sections 40 are arranged diagonally from each other in the storage section 10.

[0071] In the battery module 1 of the present invention, the gas exhaust units 30 are arranged diagonally in the accommodating unit 10, so that gas can be exhausted through the gas exhaust units 30 before it is stirred by convection. In addition, in the battery module 1 of the present invention, the air exhaust units 40 are arranged diagonally in the accommodating unit 10, so that air can be exhausted through the air exhaust units 40 before it is stirred by convection. As a result, in the battery module 1 of the present invention, gas and air are exhausted to the outside of the accommodating unit 10 while maintaining their respective layers, so that mixing of gas and air can be effectively prevented. Therefore, the battery module 1 of the present invention can effectively prevent gas from igniting or burning.

[0072] (f) The battery module 1 of the present invention is characterized in that a pair of fire extinguishing gas discharge sections 20 are provided in the vertical direction so as to face each other.

[0073] By configuring the battery module 1 of the present invention as described above in (f), the released fire extinguishing gas collides with each other near the center in the vertical direction and spreads horizontally, thereby covering the gas with the fire extinguishing gas. In other words, the battery module 1 of the present invention can form a fire extinguishing gas layer between the gas layer and the air layer. This prevents the gas from mixing with the air layer above, effectively preventing the gas from igniting or burning. Here, it is desirable to position the fire extinguishing gas discharge section 20, for example, near the center of the storage section 10 (between the first side wall 11 and the second side wall 12) in order to evenly release the fire extinguishing gas into the storage section 10.

[0074] (g) In the battery module 1 of the present invention, the control device 7 is characterized in that when the gas concentration Cd detected by the gas detection sensor 5 is less than the predetermined concentration and the fire extinguishing gas is released, the control device 7 calculates the predicted gas concentration Cd after a predetermined time has elapsed based on the average gas concentration increase rate A per predetermined time, and controls the release of the fire extinguishing gas on the condition that the predicted gas concentration is determined to be higher than the current gas concentration Cd.

[0075] By configuring the battery module 1 of the present invention as described in (g) above, it is possible to release fire-extinguishing gas even when the gas concentration Cd is below a predetermined concentration if it is determined that the predicted gas concentration Cd that would result from releasing the fire-extinguishing gas will be higher than the current gas concentration Cd. That is, even when the gas concentration Cd is below a predetermined concentration, the battery module 1 of the present invention can predictively release fire-extinguishing gas when it is determined that the average gas concentration increase rate A is fast and that it will be difficult to suppress the gas concentration Cd below the predetermined concentration even if the fire-extinguishing gas is released after the fact. As a result, the battery module 1 of the present invention can prevent the gas from filling the storage section 10 even when the gas leakage rate is fast, thereby effectively preventing the gas from igniting or burning.

[0076] (h) The battery module 1 of the present invention is characterized in that the gas detection sensor 5 is disposed on the bottom side of the storage section 10.

[0077] By configuring the battery module 1 of the present invention as described above in (h), it is possible to quickly detect gas that has a high specific gravity and tends to accumulate at the bottom of the storage section 10. As a result, the battery module 1 of the present invention can detect gas leakage before the storage section 10 is filled with gas, thereby effectively preventing the gas from igniting or burning.

[0078] (i) The battery module 1 of the present invention comprises a control device 7 and a gas detection sensor 5 that detects the gas, and the gas discharge section 30 and the air discharge section 40 are configured to be openable and closable and are normally closed, and the control device 7 controls to open the gas discharge section 30 and the air discharge section 40 and to release the fire extinguishing gas, on the condition that the gas concentration Cd detected by the gas detection sensor 5 is equal to or higher than a predetermined concentration, and controls to stop the release of the fire extinguishing gas and to close the gas discharge section 30 and the air discharge section 40, on the condition that the gas concentration Cd falls below the predetermined concentration.

[0079] By configuring the battery module 1 of the present invention as described above in (i), it is possible to prevent the gas and air from convecting inside the storage section 10 and mixing of the gas and air. Furthermore, in the battery module 1 of the present invention, the gas discharge section 30 and the air discharge section 40 are closed under normal circumstances, so that the gas concentration Cd can be detected before the gas is discharged (exhausted) from the storage section 10. As a result, the battery module 1 of the present invention can quickly detect an increase in the gas concentration Cd using the gas detection sensor 5, and therefore can more effectively prevent the gas from igniting or burning.

[0080] The above is the configuration and effects of the battery module 1 according to the modified example of the present invention. However, the battery module 1 of the present invention is not limited to the above-described embodiment and modified example, and various modifications can be made within the scope of the present invention. For example, the battery module 1 may be formed in various shapes and sizes as long as it is as described in (a) above. Furthermore, the battery module 1 of the present invention may not have some or all of the configurations described in (b) to (i) above, or may have some or all of the configurations described in (b) to (i) above and other configurations.

[0081] In the present embodiment, a battery module 1 using lithium-ion batteries is illustrated. However, the battery module 1 of the present invention can be used not only with lithium-ion batteries but also with various batteries that generate gas due to substances leaking from the cells 3, such as nickel-metal hydride batteries and fuel cells. Various numbers of cells 3, from single to multiple, can be used, and the cells 3 can be arranged in various ways, such as horizontally or stacked. Various shapes, sizes, and configurations (e.g., electrodes, electrolyte, etc.) of cells 3 can be used. Various shapes and sizes of the storage section 10 can be used depending on the number, shape, and size of the cells 3 to be stored. The storage section 10 only needs to have at least a first side wall 11 and a second side wall 12 facing each other, and may have two or more side walls. In the present embodiment, the first side wall 11 and the second side wall 12 are formed in a flat plate shape, but the first side wall 11 and the second side wall 12 may be curved or bent. In such cases, it is preferable that they be formed symmetrically to each other. Furthermore, the extinguishing gas discharge section 20 is not limited to the present embodiment and can be disposed in various positions. It is desirable to dispose the extinguishing gas discharge section 20 at a position where it can discharge the extinguishing gas toward the middle between the gas discharge section 30 and the air discharge section 40, from the viewpoint of interposing the extinguishing gas between the air layer and the gas layer. The extinguishing gas discharge section 20 does not have to be provided in pairs, and may be a single unit. The extinguishing gas discharge section 20 does not have to be provided above and below, but may also be provided, for example, on the left and right.

[0082] In this embodiment, a pair of gas discharge units 30 and a pair of air discharge units 40 are provided. However, a single gas discharge unit 30 and a single air discharge unit 40 may also be provided. The gas discharge units 30 and the air discharge units 40 can be arranged in various positions depending on the characteristics of the gases generated. To prevent the gas and air from mixing due to convection, it is desirable to provide at least one pair of gas discharge units 30 and air discharge units 40. In such a case, it is desirable to arrange the pair of gas discharge units 30, 30 in opposing or diagonal positions, and the pair of air discharge units 40, 40 in opposing or diagonal positions. In this embodiment, gases with a higher specific gravity than air, such as dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate, are illustrated. However, the present invention can be applied to various gases as long as they have a specific gravity different from that of air. For example, if the battery module 1 is a fuel cell that uses hydrogen as fuel, the gas may be hydrogen. In such a case, since hydrogen has a smaller specific gravity than air, it is preferable to arrange the gas discharge part 30 above the storage part 10 and the air discharge part 40 below the storage part 10. It is also preferable to arrange the gas detection sensor 5 above the storage part 10.

[0083] In this embodiment, the control device 7 and the extinguishing gas discharge section 20 are housed inside the housing section 10, but the control device 7 and the extinguishing gas discharge section 20 may be provided outside the housing section 10. In such a case, it is preferable that the discharge port of the extinguishing gas discharge section 20 is arranged facing the inside of the housing section 10. Furthermore, the control device 7 need not be a single one, and multiple control devices 7 may be provided according to the control unit, etc.

[0084] Various types of gas detection sensors 5 can be used depending on the characteristics of the gas, and various numbers of gas detection sensors 5 can be installed. The gas detection sensors 5 can be arranged in various positions depending on the characteristics of the gas. In this embodiment, the extinguishing gas is released on the condition that the gas concentration Cd detected by the gas detection sensor 5 is equal to or greater than half the lower flammability limit Ce. However, the concentration used as the reference for the lower flammability limit Ce can be changed as appropriate depending on the characteristics of the gas.

[0085] In addition, in this embodiment, the extinguishing gases are carbon dioxide, IG-541, IG-55, and nitrogen, but the present invention is not limited to these, and various extinguishing gases can be used. Furthermore, if the battery module 1 is a fuel cell that uses hydrogen as fuel, it is desirable to use helium or the like as the extinguishing gas, which has a specific gravity smaller than that of air and gas (hydrogen). Note that the extinguishing gas is preferably an inert gas, but is not limited to this, and extinguishing gases other than inert gas can also be used.

[0086] In this embodiment, gas ventilation paths 18 are provided between the multiple cells 3 housed in the housing portion 10, but the ventilation paths 18 may be provided as needed, and the configuration may also include no ventilation paths 18. Furthermore, when ventilation paths 18 are provided, the arrangement, shape, etc. of the ventilation paths 18 can be changed as appropriate.

[0087] In addition, in this embodiment, the configuration as described above in (g) is exemplified in order to predictively release fire extinguishing gas, but the present invention is not limited to this, and the timing of releasing fire extinguishing gas can be controlled using various calculation methods and calculation formulas.

[0088] Furthermore, in this embodiment, the gas discharge section 30 and the air discharge section 40 are normally closed, but the gas discharge section 30 and the air discharge section 40 may be always open. The gas discharge section 30 and the air discharge section 40 can be opened and closed at various times. From the viewpoint of preventing convection of gas and air, it is desirable that the gas discharge section 30 and the air discharge section 40 be configured as described above in (i), for example.

[0089] The above are various embodiments and modifications of the battery module according to the present invention. However, the present invention is not limited to the above-described embodiments and modifications, and it will be readily apparent to those skilled in the art that other embodiments may be possible within the scope of the claims in accordance with the teachings and spirit of the present invention. [Industrial Applicability]

[0090] The battery module of the present invention can be used as various battery modules (battery packs) such as lithium-ion batteries, nickel-metal hydride batteries, fuel cells, etc. The battery module of the present invention can be used as a battery (storage battery, etc.) for buildings, etc., or as a battery for electric vehicles, etc. [Explanation of symbols]

[0091] 1: Battery module 3: Cell 5: Gas detection sensor 7: Control device 10: Storage section 11:First side wall 12:Second side wall 18: Air passage 20: Fire extinguishing gas discharge section 30: Gas exhaust section 30A: First gas exhaust section 30B: Second gas exhaust section 40: Air exhaust section 40A: First air exhaust section 40B: Second air exhaust section A: Average concentration increase rate Cd: Gas concentration (detected concentration) Ce: Lower flammability limit concentration

Claims

1. A battery module having at least one cell, a storage section having at least a first side wall and a second side wall facing each other and configured to store the cell; a fire extinguishing gas discharge section that discharges a fire extinguishing gas toward the inside of the storage section; a gas exhaust unit capable of exhausting gas resulting from substances leaking from the cell; an air discharge section capable of discharging air; Equipped with The gas has a specific gravity different from that of air, at least one gas exhaust is disposed in one or both of the first side wall and the second side wall, and at least one air exhaust is disposed in one or both of the first side wall and the second side wall; The air discharge section and the gas discharge section are disposed at different positions in the vertical direction, The fire-extinguishing gas discharge portion is disposed between the first side wall and the second side wall.

2. a control device; a gas detection sensor for detecting the gas; Equipped with 2. The battery module according to claim 1, wherein the control device controls the fire extinguishing gas discharge unit to discharge the fire extinguishing gas on the condition that the gas concentration detected by the gas detection sensor is equal to or higher than a predetermined concentration.

3. 3. The battery module according to claim 1, wherein the fire extinguishing gas is an inert gas having a specific gravity greater than that of the air but less than that of the gas.

4. A plurality of the cells are accommodated in the accommodation portion, 3. The battery module according to claim 1, wherein a gas passage is provided between the plurality of cells.

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