Power storage device of all-solid-state battery

Abstract

To obtain a power storage device of an all solid state battery that can improve structural efficiency while ensuring safety during abnormal temperature rise in a power storage cell.SOLUTION: A power storage device 20 includes a power storage cell 30 that constitutes an all solid state battery element by laminating a positive electrode layer 30P, a solid electrolyte layer 33, and a negative electrode layer 30N, and a housing 22 in which at least one power storage cell 30 is housed. In addition, the power storage device 20 includes a vent 24 provided on a side surface 22A of the housing 22 and communicating between an inside and an outside of the housing 22, and an on-off valve 60 configured to be able to open and close the vent 24 on the basis of at least one of a pressure value and a temperature value within the housing 22.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power storage device for an all-solid-state battery.

Background Art

[0002] Patent Document 1 discloses a fire prevention device provided outside an internal gas discharge port of a power storage device such as a lithium-ion secondary battery. In this fire prevention device, a casing having air permeability is filled with a suppressant for ignition and / or suppression of a flame of a combustible gas, and the combustible gas discharged from the internal gas discharge port of the power storage device is brought into contact with the suppressant, thereby reducing the concentration and temperature of the internal gas and extinguishing the flame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, the practical application of so-called all-solid-state batteries using a solid solid electrolyte has been vigorously promoted as a power source for vehicle driving such as electric vehicles (EVs), hybrid vehicles (HVs), and plug-in hybrid vehicles (PHVs).

[0005] In the practical application of all-solid-state batteries, it has been considered to use at least one power storage cell that forms an all-solid-state battery element by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer in a casing to form a power storage device. In such a device structure, since it is easier to reduce the thickness of the power storage cell compared to a lithium-ion secondary battery or the like using a conventional liquid electrolyte, it is expected to achieve both miniaturization and large capacity of the device.

[0006] However, when applying the fire prevention device described in Patent Document 1 to the power storage device of the all-solid-state battery, in order to secure a space for arranging the inhibitor during a rapid temperature rise of the power storage cell, the housing for housing the power storage cell becomes larger, which may cause an adverse effect on the expected structural efficiency.

[0007] In view of the above facts, an object of the present invention is to obtain a power storage device for an all-solid-state battery that can improve structural efficiency while ensuring safety during an abnormal temperature rise of the power storage cell.

Means for Solving the Problems

[0008] According to the first aspect The power storage device of the all-solid-state battery includes a power storage cell that forms an all-solid-state battery element by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, a housing that houses at least one of the power storage cells, a ventilation port provided on a side surface of the housing for communicating the inside and outside of the housing, and an on-off valve configured to be able to open and close the ventilation port based on at least one of the pressure value and the temperature value inside the housing. a valve control unit that controls the opening and closing of the on-off valve, and has and the valve control unit opens the on-off valve when at least one of the pressure value and the temperature value inside the housing is equal to or higher than a first threshold value provided for detecting a rapid temperature rise of the storage battery cell, and after opening the on-off valve based on the first threshold value, when at least one of the pressure value and the temperature value inside the housing becomes lower than the first threshold value and lower than a second threshold value set to avoid deformation of the housing, the on-off valve is closed 。

[0009] According to the first aspect In the power storage device of the all-solid-state battery, an on-off valve is provided at the ventilation port that communicates the inside and outside of the housing. This on-off valve opens and closes the ventilation port based on at least one of the pressure value and the temperature value inside the housing. Thereby, even during a rapid temperature rise of the cell, the internal pressure of the housing can be adjusted by opening and closing the on-off valve, and damage to the housing can be avoided. In addition, it is not necessary to arrange an inhibitor for suppressing the temperature rise of the power storage cell between the power storage cell and the housing, and it is easy to make the housing thinner and save space. Thereby, it is possible to improve the structural efficiency while ensuring safety during an abnormal temperature rise of the power storage cell.

[0010] In addition, the power storage device of the all-solid-state battery according to the first aspect further includes a valve control unit that controls the opening and closing of the on-off valve. The valve control unit opens the on-off valve when at least one of the pressure value and the temperature value inside the housing is equal to or higher than a first threshold value provided for detecting a rapid temperature rise of the storage battery cell, and after opening the on-off valve based on the first threshold value, when at least one of the pressure value and the temperature value inside the housing becomes lower than the first threshold value and lower than a second threshold value set to avoid deformation of the housing, the on-off valve is closed.

[0011] In this way, in the power storage device of the all-solid-state battery according to the first aspect, since a rapid temperature rise of the storage battery cell can be detected and the on-off valve can be opened, it is possible to suppress damage to the housing due to a rapid increase in the internal pressure of the housing. Further, in the power storage device of the all-solid-state battery according to the first aspect, when the internal pressure has dropped to a state where deformation of the housing can be avoided after the on-off valve is opened along with a rapid temperature rise of the storage battery cell, the on-off valve is closed again. As a result, the inside of the housing becomes a sealed space again, and the risk of ignition due to the introduction of outside air into the housing by the opening of the on-off valve can be reduced.

[0012] The power storage device of the all-solid-state battery according to the second aspect is, in the first aspect, wherein the housing is composed of an exterior body made of a laminated film.

[0013] In the power storage device of the all-solid-state battery according to the second aspect, since the housing is composed of an exterior body made of a laminated film, the gap provided between the storage battery cell and the housing can be minimized, and the structural efficiency can be further improved.

[0014] The power storage device of the all-solid-state battery according to the third aspect is, in the first aspect or the second aspect, wherein the on-off valve is configured to slide along the side surface of the housing to open and close the ventilation port.

[0015] In the power storage device of the all-solid-state battery according to the third aspect, since the on-off valve slides along the side surface of the housing, an increase in the size of the housing to secure a movable space for the on-off valve is suppressed.

[0018] According to the fourth aspect In the power storage device of the all-solid-state battery, The first aspect wherein, after the valve control unit closes the on-off valve based on the second threshold value, when the temperature gradient in the housing is negative and the temperature value is lower than the ignition temperature of the combustible gas that can be generated from the power storage cell, the on-off valve is opened.

[0019] According to the fourth aspect In the power storage device of the all-solid-state battery, when the temperature gradient in the housing is negative and the temperature value in the housing is lower than the ignition temperature of the combustible gas that can be generated from the power storage cell, the on-off valve is opened again. As a result, while ensuring safety, the high-temperature gas inside the housing can be discharged, so that the temperature inside the housing can be efficiently lowered.

Advantages of the Invention

[0020] As described above, the power storage device of the all-solid-state battery according to the present invention can improve the structural efficiency while ensuring safety during abnormal temperature rise of the power storage cell. Together, it is possible to suppress damage to the housing due to a rapid increase in the internal pressure of the housing, and further, it is possible to reduce the risk of ignition due to the introduction of air outside the housing by opening the on-off valve. It has the excellent effect of

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0022] Hereinafter, with reference to FIGS. 1 to 6, a power storage device 20 according to an embodiment of the present invention will be described.

[0023] The vehicle 10 shown in FIG. 1 includes a power storage device 20, a valve opening / closing control ECU 40, and a drive source 50. The vehicle 10 includes an electric motor (not shown) as a drive source 50 for traveling, and the electric motor is driven using the electric power stored in the power storage device 20.

[0024] As shown in FIG. 2, the power storage device 20 includes a plurality of power storage cells 30 that constitute an all-solid-state battery element, and a housing 22 in which the plurality of power storage cells 30 are housed. On a side surface 22A (upper surface side in FIG. 2) of the housing 22, a vent hole 24 (see FIG. 4) that communicates the inside and outside of the housing 22 and an opening / closing valve 60 that opens and closes the vent hole 24 are provided.

[0025] Also, inside the housing 22, a pressure sensor 52 that detects the pressure value inside the housing and a temperature sensor 54 that detects the temperature value inside the housing are provided.

[0026] As shown in FIG. 3, each power storage cell 30 is a lithium-ion secondary battery, and a positive electrode layer 30P, a solid electrolyte layer 33, and a negative electrode layer 30N are laminated to form an all-solid-state battery element. In FIG. 3, the lamination direction H1 and the surface direction W1 of each layer of the power storage cell 30 are shown.

[0027] The positive electrode layer 30P is composed of a positive electrode current collector layer 31 having a positive electrode current collector tab 31A and a positive electrode active material layer 32. The negative electrode layer 30N is composed of a negative electrode active material layer 34 and a negative electrode current collector layer 35 having a negative electrode current collector tab 35A.

[0028] The constituent material of the positive electrode current collector layer 31 is, for example, SUS, aluminum, copper, nickel, iron, titanium, or carbon, but is not limited thereto.

[0029] The positive electrode active material layer 32 contains at least a positive electrode active material. The material of the positive electrode active material is, for example, lithium cobaltate (LiCoO2), lithium nickelate (LiNiO2), lithium manganate (LiMn2O4), but is not limited thereto.

[0030] The solid electrolyte layer 33 contains at least a solid electrolyte. The material of the solid electrolyte is not particularly limited, and a material that can be used as the solid electrolyte of an all-solid-state battery can be used.

[0031] The negative electrode active material layer 34 contains lithium titanate (LTO), a binder for binding LTO particles to each other, and a conductive aid.

[0032] The material used for the negative electrode current collector layer 35 is, for example, the material used for the positive electrode current collector layer 31.

[0033] The power storage cell 30 is composed of a positive electrode current collector layer 31, a positive electrode active material layer 32, a solid electrolyte layer 33, a negative electrode active material layer 34, and a negative electrode current collector layer 35 laminated in this order to form one all-solid-state battery element. Note that FIG. 3 illustrates a configuration in which one power storage cell 30 includes one all-solid-state battery element, but is not limited thereto, and one power storage cell may be composed of a laminate of a plurality of all-solid-state battery elements. In this case, the positive electrode current collector layer 31 and the negative electrode current collector layer 35 may be shared between adjacent all-solid-state battery elements, and a plurality of them may be laminated with the lamination order of each layer being opposite to each other.

[0034] The housing 22 is formed in a flat rectangular shape in the height direction of the power storage device 20. As the material of this housing, a metal material, a resin material, etc. can be appropriately adopted. In an example of this embodiment, it is composed of an exterior body made of a laminate film.

[0035] The laminated film is composed of a resin-laminated metal foil having resin films on one or both sides of a metal foil. The resin-laminated metal foil has, for example, a resin film for imparting mechanical strength laminated on one side of the metal foil and a resin film having heat-sealing properties laminated on the opposite side.

[0036] The metal foil in the resin-laminated metal foil may be, for example, a foil made of aluminum, an aluminum alloy, or the like. The resin film for maintaining mechanical strength may be, for example, a film made of polyester, nylon, or the like. The resin film having heat-sealing properties may be, for example, a film made of polyolefin or the like, and specifically, may be a film made of polyethylene, polypropylene, or the like.

[0037] Such a housing 22 opposes two laminated films with the resin film having heat-sealing properties on the inside, and disposes the power storage cell 30 in the gap therebetween. The four outer peripheral sides of the laminated film are sealed by heat-sealing to form a bag-shaped exterior body. Thereby, the power storage cell 30 is housed in the exterior body made of the laminated film.

[0038] As shown in FIGS. 4(A) and 4(B), the on-off valve 60 is attached to the vent hole 24 provided in the side surface 22A of the housing 22, and its opening and closing are controlled by a valve control ECU 40 described later. The on-off valve 60 is composed of, for example, a known slide valve, and includes a slider 62 that slides along the side surface of the housing 22 between a closed position (FIG. 4(A)) that closes the vent hole 24 and an open position (FIG. 4(B)) that opens the vent hole 24, and an electric actuator 56 that drives the slider 62.

[0039] In the closed state of the on-off valve 60, the slider 62 is disposed at the closed position shown in FIG. 4(A). In this state, the vent hole of the housing 22 is blocked by the slider 62, and the housing 22 is sealed. On the other hand, in the released state of the on-off valve 60, the slider 62 is disposed at the open position shown in FIG. 4(B). In this state, the vent hole 24 of the housing 22 is opened, and the inside and outside of the housing 22 communicate with each other through the vent hole 24.

[0040] The on-off valve 60 is controlled to open and close by the valve control ECU 40. Hereinafter, the configuration of the valve control ECU 40 will be described.

[0041] As shown in FIG. 5, the valve control ECU 40 includes, as a hardware configuration, a CPU (Central Processing Unit) 41, a ROM (Read Only Memory) 42, a RAM (Random Access Memory) 43, a storage 44, a communication interface (I / F) 45, and an input / output interface (I / F) 46. The CPU 41, the ROM 42, the RAM 43, the storage 44, the communication I / F 45, and the input / output I / F 46 are communicably connected to each other via an internal bus 47.

[0042] The CPU 41 is a central arithmetic processing unit that executes various programs and controls each part. The CPU 41 reads a program from the ROM 42 or the storage 44 and executes the program using the RAM 43 as a work area. The CPU 41 performs control of each component and various arithmetic processes according to the program recorded in the ROM 42 or the storage 44.

[0043] The ROM 42 stores various programs and various data. The RAM 43 temporarily stores a program or data as a work area. The storage 44 is composed of a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs and various data.

[0044] The communication I / F 45 is an interface for the valve control ECU 40 to communicate with other devices.

[0045] The input / output I / F 46 is an interface for communicating with each device mounted on the vehicle 10. In the present embodiment, the pressure sensor 52, the temperature sensor 54, and the actuator 56 are connected to the input / output I / F 46.

[0046] Also, the valve control ECU 40 has an acquisition unit 410 and a valve control unit 420 as functional configurations. The functions of the acquisition unit 410 and the valve control unit 420 are realized by the CPU 41 reading and executing a program stored in the ROM 42.

[0047] The acquisition unit 410 acquires information regarding the pressure value inside the housing 22 detected by the pressure sensor 52 and the temperature value inside the housing 22 detected by the temperature sensor 54.

[0048] The valve control unit 420 controls the opening and closing of the on-off valve 60 based on at least one of the pressure value and the temperature value inside the housing 22 acquired by the acquisition unit 410. Specifically, in the present embodiment, a stepwise threshold value for inferring the internal environment of the housing 22 is provided based on at least one of the pressure value and the temperature value inside the housing 22.

[0049] Here, when a combustible gas is generated inside the housing 22 due to overcharging or the like of some of the power storage cells 30 inside the housing 22, and this serves as a trigger for a short circuit in the circuit, the temperature of the power storage cells 30 may rapidly increase. When the temperature increase of the power storage cells 30 leads to ignition, it has been found that the temperature exceeds 1000 degrees [C] immediately after ignition, and then the temperature rapidly decreases.

[0050] In such a phenomenon, the pressure inside the housing 22 may exceed the rupture pressure resistance of the housing 22 due to the temperature increase immediately after ignition. Reducing the pressure inside the housing 22 rapidly to avoid damage to the housing 22 is important for ensuring safety.

[0051] When the valve control unit 420 assumes the occurrence of an abnormality in the power storage cell 30 as described above, when at least one of the pressure value and the temperature value in the housing 22 is equal to or higher than a first threshold value provided for detecting a rapid temperature rise of the power storage cell 30, the actuator 56 is driven to open the on-off valve 60 to an open state. Thereby, the internal pressure of the housing 22 is reduced to avoid damage to the housing 22.

[0052] This first threshold value may be set to the temperature immediately after ignition of the power storage cell 30 based on the temperature value in the housing 22, or the burst pressure resistance of the housing 22 may be set based on the pressure value in the housing 22, or it may be set by a combination of these.

[0053] Further, after the valve control unit 420 opens the on-off valve 60 based on the first threshold value, when at least one of the pressure value and the temperature value in the housing 22 is lower than the first threshold value and less than a second threshold value set to avoid deformation of the housing 22, the on-off valve 60 is closed again. Thereby, the housing 22 can be sealed and the outside air can be blocked, so that the ignition of the power storage cell 30 can be suppressed or extinguished.

[0054] This second threshold value may be set based on the temperature value in the housing 22, may be set based on the pressure value in the housing 22, or may be set by a combination of these.

[0055] Furthermore, after the valve control unit 420 closes the on-off valve 60 based on the second threshold value, when the temperature gradient in the housing 22 within a predetermined time is negative and the temperature value in the housing 22 is lower than the ignition temperature of the combustible gas that can be generated from the power storage cell 30, the on-off valve 60 is opened. Thereby, since the high-temperature gas inside the housing 22 can be discharged while ensuring safety, the temperature inside the housing 22 can be efficiently lowered.

[0056] Next, an example of the valve opening / closing process executed by the valve control ECU 40 will be described with reference to the flowchart shown in FIG. 6. This valve control process is performed by the CPU 41 reading a program from the RO 42 or the storage 44 and expanding and executing it in the RAM 43.

[0057] As shown in FIG. 6, in step S101, the CPU 41 determines whether at least one of the pressure value and the temperature value in the housing 22 is equal to or greater than the first threshold value. Specifically, when the CPU 41 determines, by the functions of the acquisition unit 410 and the valve control unit 420, that at least one of the pressure value and the temperature value is equal to or greater than the first threshold value, the process proceeds to step S102.

[0058] In step S102, the CPU 41 determines that a rapid temperature rise has occurred in the power storage cell 30, and opens the on-off valve 60. Thereby, the internal pressure of the housing 22 is reduced, and damage to the housing 22 due to an increase in the internal pressure is avoided.

[0059] On the other hand, in step S103, when the CPU 41 determines that no abnormality has been detected in the power storage cell 30, the CPU 41 does not operate the on-off valve 60.

[0060] In step S104, the CPU 41 determines whether at least one of the pressure value and the temperature value in the housing 22 is less than the second threshold value. When the CPU 41 determines that at least one of the pressure value and the temperature value is less than the second threshold value, the process proceeds to step S105.

[0061] In step S105, when the CPU 41 determines that the housing 22 will not be deformed even if the on-off valve 60 is closed, the CPU 41 closes the on-off valve 60 again. Thereby, it is possible to suppress ignition caused by the power storage cell 30 in the housing 22 coming into contact with outside air. Further, by making the inside of the housing 22 a sealed space again, the flame can be extinguished.

[0062] On the other hand, if it is determined in step S104 that the value is equal to or greater than the second threshold value, the process returns to the process of step S102.

[0063] In step S106, the CPU 41 determines whether the temperature gradient inside the housing 22 within a predetermined time is negative and less than the ignition temperature of the flammable gas. That is, in step S106, if the temperature inside the housing 22 continues to decrease and the internal temperature is less than the ignition temperature of the flammable gas, the CPU 41 determines that the power storage cell 30 will not ignite even if the on-off valve 60 is opened, and proceeds to step S107.

[0064] 」 In step S107, the CPU 41 opens the on-off valve 60, discharges the high-temperature gas inside the housing 22, and returns to the process of step S102 again.

[0065] On the other hand, if a negative determination is made in step S106, the CPU 41 considers that there is a possibility that ignition continues inside the housing 22, and returns to the process of step S105.

[0066] (Function and Effect) As described above, in the power storage device 20 according to the present embodiment, the on-off valve 60 is provided at the vent 24 that communicates the inside and outside of the housing 22. This on-off valve 60 opens and closes the vent 24 based on at least one of the pressure value and the temperature value inside the housing 22. Thereby, even when the temperature of the power storage cell 30 rises rapidly, the internal pressure of the housing 22 can be adjusted by opening and closing the on-off valve 60, and damage to the housing 22 can be avoided. In addition, it is not necessary to arrange a suppressant for suppressing the temperature rise of the power storage cell 30 between the power storage cell 30 and the housing 22, and the housing 22 can be easily thinned and space-saving. Thereby, the structural efficiency can be improved while ensuring the safety when the temperature of the power storage cell 30 rises abnormally.

[0067] Further, in the present embodiment, since the housing 22 is constituted by an exterior body made of a laminate film, the gap provided between the power storage cell 30 and the housing 22 can be minimized. Thereby, the structural efficiency can be further improved.

[0068] In addition, in the present embodiment, since the on-off valve 60 slides along the side surface of the housing 22, an increase in the size of the housing 22 is suppressed in order to secure a movable space for the on-off valve 60.

[0069] Further, in the present embodiment, since a rapid temperature rise of the power storage cell 30 can be detected and the on-off valve 60 can be opened, damage to the housing 22 due to a rapid increase in the internal pressure of the housing 22 can be suppressed.

[0070] Moreover, in the present embodiment, after the on-off valve 60 is opened following a rapid temperature rise of the power storage cell 30, when the internal pressure has decreased to a state where deformation of the housing 22 can be avoided, the on-off valve 60 is closed again. As a result, the inside of the housing 22 becomes a sealed space again, and the risk of ignition due to the introduction of outside air into the housing 22 by the opening of the on-off valve 60 can be reduced.

[0071] Also, in the present embodiment, when the temperature gradient inside the housing is negative and the temperature value inside the housing is less than the ignition temperature of the combustible gas that can be generated from the power storage cell, the on-off valve is opened again. As a result, since the high-temperature gas inside the housing can be discharged while ensuring safety, the temperature inside the housing can be efficiently lowered. [Supplementary Explanation]

[0072] As described above, the positional embodiments of the present invention have been explained, but the present invention is not limited to this. Each configuration of the present invention can be implemented with various modifications without departing from the gist thereof.

Explanation of Reference Numerals

[0073] 20 Power storage device 22 Housing 22A Side surface 24 Vent 30 Power storage cell 30P Positive electrode layer 30N Negative electrode layer 33 Solid electrolyte layer 60 On-off valve 420 Valve control unit

Claims

1. A power storage cell that forms a all-solid-state battery element by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, A housing that houses at least one of the power storage cells, A vent provided on a side surface of the housing to communicate the inside and outside of the housing, An on-off valve configured to be able to open and close the vent based on at least one of a pressure value and a temperature value inside the housing, A valve control unit that controls the opening and closing of the on-off valve, having, The valve control unit opens the on-off valve when at least one of the pressure value and the temperature value inside the housing is equal to or higher than a first threshold value provided for detecting a rapid temperature rise of the power storage cell, and after opening the on-off valve based on the first threshold value, when at least one of the pressure value and the temperature value inside the housing is lower than the first threshold value and lower than a second threshold value set to avoid deformation of the housing, the on-off valve is closed, The housing is a power storage device of an all-solid-state battery composed of an exterior body made of a laminate film.

2. A power storage cell that forms a all-solid-state battery element by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, A housing that houses at least one of the power storage cells, A vent provided on a side surface of the housing to communicate the inside and outside of the housing, An on-off valve configured to be able to open and close the vent based on at least one of a pressure value and a temperature value inside the housing, A valve control unit that controls the opening and closing of the on-off valve, having, When at least one of the pressure value and the temperature value in the housing is equal to or higher than a first threshold value provided for detecting a rapid temperature rise of the storage battery cell, the valve control unit opens the on-off valve. After opening the on-off valve based on the first threshold value, when at least one of the pressure value and the temperature value in the housing becomes lower than the first threshold value and lower than a second threshold value set to avoid deformation of the housing, the on-off valve is closed. Further, after closing the on-off valve based on the second threshold value, when the temperature gradient in the housing is negative and the temperature value is lower than the ignition temperature of the combustible gas that can be generated from the storage battery cell, the on-off valve is opened. A power storage device for an all-solid-state battery.

3. The on-off valve according to claim 1 or 2, wherein the on-off valve slides along a side surface of the housing and is configured to open and close the ventilation port.

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