JP2022014295A - All-solid battery pack - Google Patents

Abstract

To provide an all-solid battery pack that uses an all-solid battery including a sulfide-based solid electrolyte as a battery cell, the battery pack preventing corrosion of battery constituent members caused by a basic material and heat propagation caused by high-temperature gas in an abnormal state.SOLUTION: An all-solid battery pack disclosed herein includes: a plurality of all-solid battery cells; a housing; a heat detection unit that detects the temperature of the all-solid battery cells; a hydrogen sulfide gas detection unit that detects the concentration of hydrogen sulfide gas; an inert gas storage unit; a basic gas storage unit; and a plurality of gas exhaust ports. The all-solid battery cells each include a positive electrode, a negative electrode, and a sulfide-based solid electrolyte. When the temperature of one of the all-solid battery cells increases to a threshold or higher, the all-solid battery pack blows off the inert gas from the gas exhaust port closest to the all-solid battery cell whose temperature has increased, and when moreover the concentration of the hydrogen sulfide gas increases to a threshold or higher, blows off the basic gas in addition to the inert gas.SELECTED DRAWING: Figure 2

Description

The present invention relates to an all-solid-state battery pack.

With the widespread use of secondary batteries such as lithium secondary batteries, further improvement in performance is desired. As a high-performance secondary battery, an all-solid-state battery in which an electrolytic solution is replaced with a solid electrolyte is attracting attention.

Among the solid electrolytes, the sulfide-based solid electrolyte is excellent in ionic conductivity and the like. However, the sulfide-based solid electrolyte has a problem that it reacts with water to generate hydrogen sulfide gas. On the other hand, in Patent Document 1, hydrogen sulfide gas is generated by mixing a sulfide-based solid electrolyte and a basic material and including the basic material in a battery (particularly an electrode or a solid electrolyte layer). Suppressing techniques have been proposed.

Japanese Unexamined Patent Publication No. 2011-165650

However, when a basic material is contained in the battery as in the prior art, the metal foil of the electrode collector (particularly aluminum foil) or the aluminum base material of the laminate case reacts with the basic material. , There is a problem that it may cause corrosion. In addition, when constructing a battery pack using an all-solid-state battery using a sulfide-based solid electrolyte as a battery cell in order to increase the capacity and energy density, a high-temperature gas is generated when an abnormality occurs in the battery cell. There is a problem that the temperature of the entire battery pack may rise excessively due to the heat propagation caused by this high temperature gas.

Therefore, an object of the present invention is a battery pack using an all-solid-state battery containing a sulfide-based solid electrolyte as a battery cell, in which corrosion of battery components by a basic material and heat propagation by a high-temperature gas at an abnormal time are performed. Is to provide a battery pack that is suppressed.

The all-solid-state battery pack disclosed herein includes a plurality of arranged all-solid-state battery cells, a housing accommodating the plurality of all-solid-state battery cells, and the plurality of all-solid-state battery cells arranged in the housing. A heat detection unit that detects the temperature of the gas, a hydrogen sulfide gas detection unit that is arranged in the housing and detects the concentration of the hydrogen sulfide gas, an inert gas storage unit, a basic gas storage unit, and the inert gas. It includes a plurality of gas outlets for ejecting an inert gas from the accommodating portion and a basic gas from the basic gas accommodating portion into the housing. The all-solid-state battery cell includes a positive electrode, a negative electrode, and a sulfide-based solid electrolyte. When the temperature of the all-solid-state battery cell rises above the threshold value, the all-solid-state battery pack ejects an inert gas from the gas outlet closest to the all-solid-state battery cell whose temperature has risen, and further, the hydrogen sulfide. When the concentration of the gas rises above the threshold value, the basic gas is ejected in addition to the inert gas.

According to such a configuration, the basic material can be stored in a storage portion different from the storage portion in which the all-solid-state battery cell is housed, and the basic gas is used as the all-solid-state battery only when hydrogen sulfide gas is generated. Since it can be introduced into the portion where the cell is housed, it is possible to suppress corrosion of the battery component due to the basic material. In addition, by ejecting an inert gas when an abnormality occurs in the all-solid-state battery cell, the reaction that occurs when the all-solid-state battery cell is abnormal can be suppressed, and the generation of high-temperature gas can be suppressed to promote heat propagation. It can be suppressed. That is, according to such a configuration, the battery pack uses an all-solid-state battery containing a sulfide-based solid electrolyte as the battery cell, and the battery components are corroded by the basic material and the heat due to the high temperature gas at the time of abnormality occurs. A battery pack with suppressed propagation is provided.

It is a schematic diagram which shows an example of the structure of the all-solid-state battery pack which concerns on one Embodiment of this invention. It is a flowchart which shows an example of the control performed by the all-solid-state battery pack which concerns on one Embodiment of this invention.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. Matters not mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The present invention can be carried out based on the contents disclosed in the present specification and the common general technical knowledge in the art. Further, in the following drawings, members / parts having the same action are described with the same reference numerals. Further, the dimensional relations (length, width, thickness, etc.) in each drawing do not reflect the actual dimensional relations.

As used herein, the term "battery" refers to a general storage device capable of extracting electrical energy, and is a concept including a primary battery and a secondary battery. As used herein, the term "secondary battery" refers to a general storage device that can be repeatedly charged and discharged, and is a so-called storage battery (that is, a chemical battery) such as a lithium ion secondary battery, a nickel hydrogen battery, or a nickel cadmium battery, as well as an electric secondary battery. Includes capacitors (ie, physical batteries) such as multi-layer capacitors.

FIG. 1 schematically shows the configuration of the all-solid-state battery pack according to the present embodiment. The all-solid-state battery pack 100 includes a plurality of all-solid-state battery cells 10. The plurality of all-solid-state battery cells 10 are arranged along the X direction in FIG. 1 (hence, in the following description, the "X direction" is also referred to as "arrangement direction X"). The plurality of all-solid-state battery cells 10 are electrically connected in series or in parallel. The plurality of all-solid-state battery cells 10 may be constrained by a restraining member or the like. The number of all-solid-state battery cells 10 included in the all-solid-state battery pack 100 is 13 in the illustrated example, but the number is not limited to this, and can be appropriately set.

Each all-solid-state battery cell 10 includes a positive electrode, a negative electrode, and a sulfide-based solid electrolyte interposed between the positive electrode and the negative electrode. The positive electrode usually includes a positive electrode current collector and a positive electrode active material layer. The negative electrode usually includes a negative electrode current collector and a negative electrode active material layer. Further, the sulfide-based fixed electrolyte is arranged as a layer between the positive electrode and the negative electrode.

Therefore, in the present embodiment, in each all-solid-state battery cell 10, a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are laminated in this order.

For the positive electrode current collector and the negative electrode current collector, known current collectors that can be used for all-solid-state batteries may be used, and for example, metals such as silver, copper, gold, aluminum, nickel, iron, stainless steel, and titanium. Sheet body or foil-like body can be used. Aluminum foil is preferable as the positive electrode current collector. A copper foil is preferable as a negative electrode current collector.

The positive electrode active material layer contains a positive electrode active material and optionally a conductive material, a binder, and a solid electrolyte. As the positive electrode active material, a known positive electrode active material that can be used in an all-solid-state battery may be used, and examples thereof include lithium nickel-based composite oxide, lithium cobalt-based composite oxide, lithium manganese-based composite oxide, and lithium. Lithium transition metal composite oxides such as nickel-cobalt-based composite oxides, lithium nickel-manganese-based composite oxides, and lithium nickel-cobalt manganese-based composite oxides; lithium composite compounds having an olivine structure such as LiFePO ₄ and the like can be mentioned. As the conductive material and binder of the positive electrode active material layer, known conductive materials and binders that can be used for all-solid-state batteries may be used. Examples of the solid electrolyte include the same sulfide-based solid electrolytes contained in the solid electrolyte layer described later.

The solid electrolyte layer contains a sulfide-based solid electrolyte. Examples of the sulfide solid electrolyte include Li 2S—SiS ₂ system, Li ₂ SP ₂ S ₃ system, Li ₂ SP ₂ S ₅ system, Li ₂ S _— GeS ₂ system, Li ₂ SB. Examples thereof include glass or glass ceramics such as ₂ S ₃ series, Li ₃ PO ₄ -P ₂ S ₅ series, Li ₄ SiO ₄ -Li ₂ S-SiS ₂ series. Further, from the viewpoint of achieving higher ionic conductivity, a Li 2S _- based solid solution composed of Li 2S and lithium halide ₍ for example, LiCl, LiBr, LiI) is preferably used. Preferable examples of such a sulfide solid electrolyte include LiBr-Li ₂ SP ₂ S ₅ , LiI-Li ₂ SP ₂ S ₅ , LiBr-LiI-Li ₂ SP ₂ S ₅ , and the like. ..

The negative electrode active material layer contains a negative electrode active material and optionally a conductive material, a binder, and a solid electrolyte. As the negative electrode active material, a known negative electrode active material that can be used for all-solid-state batteries may be used, and examples thereof include carbon-based negative electrode active materials such as graphite, hard carbon, soft carbon, and carbon nanotubes; Si, silicon oxide. , Si-based negative electrode active material such as silicon carbide and silicon nitride; Sn-based negative electrode active material such as Sn, tin oxide, tin nitride and tin-containing alloy can be mentioned. As the conductive material and binder of the negative electrode active material layer, known conductive materials and binders that can be used for all-solid-state batteries may be used. Examples of the solid electrolyte include the same sulfide-based solid electrolytes contained in the above-mentioned solid electrolyte layer.

In the all-solid-state battery cell 10, usually, a laminated body in which these are laminated in order is housed in a battery case. The battery case may be a known one used for all-solid-state battery cells, for example, a laminated case. The laminated case has, for example, an aluminum base material layer, and further has a resin layer such as a sealant layer and a protective layer.

Spacers (not shown) may be arranged between adjacent all-solid-state battery cells 10. As the spacer, a heat insulating plate, a heat radiating plate, or the like used in a known all-solid-state battery pack may be used.

As shown in FIG. 1, a plurality of all-solid-state battery cells 10 are housed in the housing 20. The housing 20 may be made of the same material as the housing used for known all-solid-state battery packs, and may have the same dimensions.

Inside the housing 20 of the all-solid-state battery pack 100, a heat detection unit 30 for detecting the temperatures of all the plurality of all-solid-state battery cells 10 is arranged. The heat detection unit 30 is, for example, a temperature sensor. The temperature sensor may be a contact type or a non-contact type. When the temperature sensor is a non-contact type, the heat detection unit 30 is installed at a position where the temperature of all the plurality of all-solid-state battery cells 10 can be measured. When the heat detection unit 30 is a contact-type temperature sensor, the temperature sensor has, for example, the same number of thermocouples as the all-solid-state battery cell 10, and each thermocouple is attached to each of the all-solid-state battery cells 10. Has been done.

A hydrogen sulfide gas detecting unit 40 for detecting the concentration of hydrogen sulfide ( _H2S ) gas is arranged in the housing 20 of the all-solid-state battery pack 100. The hydrogen sulfide gas detection unit 40 is, for example, a hydrogen sulfide gas concentration sensor. In the illustrated example, only one hydrogen sulfide gas detection unit 40 is installed in the housing 20. However, the installation form of the hydrogen sulfide gas detection unit 40 is not limited to this, and a plurality of hydrogen sulfide gas detection units 40 may be installed in the housing 20 at regular intervals or the like, or the all-solid-state battery cell 10 may be installed. The same number of hydrogen sulfide gas detection units 40 as above may be arranged near each all-solid-state battery cell 10.

The all-solid-state battery pack 100 includes an inert gas accommodating portion 50. The inert gas accommodating portion 50 is typically a closed container such as a gas cylinder. When the all-solid-state battery pack 100 is used, the inert gas accommodating portion 50 is filled with the inert gas. The inert gas is a gas that does not react with the constituent materials of the all-solid-state battery cell 10 (particularly, a gas that does not contain water and oxygen), and is, for example, nitrogen gas, argon gas, helium gas, or the like. In the illustrated example, the inert gas accommodating portion 50 is arranged outside the housing 20, but the arrangement of the inert gas accommodating portion 50 is not limited to this.

The all-solid-state battery pack 100 includes a basic gas accommodating portion 60. The basic gas accommodating portion 60 is typically a closed container such as a gas cylinder. In the present embodiment, a basic gas (that is, a gaseous substance of a basic compound) is used as a basic material for neutralizing hydrogen sulfide gas, and when the all-solid battery pack 100 is used, the basic gas accommodating portion is used. 60 is filled with a basic gas. The basic gas is a gas capable of neutralizing hydrogen sulfide gas, for example, ammonia gas and amines gas. By sealing the basic gas in the basic gas accommodating portion 60, the basic gas is stored in isolation from the all-solid-state battery cell 10. Therefore, corrosion of the constituent members of the all-solid-state battery cell 10 due to the basic gas in the normal state is prevented. The basic gas accommodating portion 60 is arranged outside the housing 20, but the arrangement of the basic gas accommodating portion 60 is not limited to this as long as the basic gas is isolated from the all-solid-state battery cell 10.

The all-solid-state battery pack 100 has a gas flow path 70 for supplying the inert gas and the basic gas from the inert gas accommodating portion 50 and the basic gas accommodating portion 60, respectively, in the housing 20. At the connection portion between the gas flow path 70 and the inert gas accommodating portion 50 and the basic gas accommodating portion 60, the inert gas accommodating portion 50 and the basic gas accommodating portion 60 can be opened and closed, respectively. (Not shown) is provided. The valve is, for example, a solenoid valve. In the illustrated example, the inert gas and the basic gas are supplied into the housing 20 through the same gas flow path 70. However, the gas flow path for the inert gas and the gas flow path for the basic gas may be formed separately.

A plurality of gas outlets 80 (80A to 80E) are provided at the connection portion between the gas flow path 70 and the housing 20. By providing the all-solid-state battery pack 100 with a plurality of gas injection ports 80, it is possible to efficiently inject gas into the all-solid-state battery cell 10 in which an abnormality has occurred. The gas outlet 80 is configured as, for example, an injection nozzle (not shown). When the gas can be injected by the pressure difference between the inert gas accommodating portion 50 and the basic gas accommodating portion 60 and the inside of the housing 20, the gas outlet 80 can be opened and closed by a valve (for example, a solenoid valve). It can also be configured. In the illustrated example, the all-solid-state battery pack 100 has five gas outlets 80, but the number of gas outlets 80 is not limited to this. For example, one gas outlet 80 may be used for each one, two, three, or four all-solid-state battery cells.

Further, the all-solid-state battery pack 100 includes a control unit 90. The control unit 90 is provided outside the housing 20. However, the control unit 90 may be provided in the housing 20. Although not shown, the control unit 90 is connected to each of the heat detection unit 30, the hydrogen sulfide gas detection unit 40, the inert gas accommodating unit 50, the basic gas accommodating unit 60, and the gas outlet 80.

The control unit 90 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. For example, the ROM stores a program for operating the all-solid-state battery pack 100 as described later.

When the temperature of the all-solid-state battery cell 10 rises above the threshold value by the control unit 90, the all-solid-state battery pack 100 injects an inert gas from the gas outlet 80 closest to the raised all-solid-state battery cell 10. It is configured as. At this time, if there are two or more closest gas outlets, the inert gas may be injected from any one of the gas outlets 80, or the inert gas may be injected from all the outlets 80. It may be configured to inject. The temperature threshold value may be appropriately set according to the constituent materials of the all-solid-state battery cell in consideration of the temperature that can be reached at the time of abnormality. In an all-solid-state battery using a sulfide-based solid electrolyte, the threshold value is, for example, 700 ° C. in consideration of the generation of high-temperature gas having a temperature of 700 ° C. or higher. In addition to this, the all-solid-state battery pack 100 is configured by the control unit 90 to eject a basic gas in addition to the inert gas when the concentration of the hydrogen sulfide gas rises above the threshold value. At this time, from the viewpoint of preventing the excess of the basic gas, the amount of the gaseous basic compound is approximately the same molar amount with respect to the gaseous hydrogen sulfide (for example, 1 mol to 1.2 times with respect to the gaseous hydrogen sulfide). Injecting the compound so as to be a basic compound (molar times larger) is advantageous because it can minimize the corrosion of the battery components due to the basic gas even in an abnormal situation. The threshold value of the concentration of hydrogen sulfide gas may be appropriately determined in consideration of the constituent materials of the all-solid-state battery cell, the volume of the housing 20, the volume of the all-solid-state battery cell, and the like. Such a configuration of the all-solid-state battery pack 100 will be specifically described with reference to the flowchart shown in FIG. 2 as an example.

As shown in FIG. 2, first, at the start, the temperature of each all-solid-state battery cell 10 is monitored by the heat detection unit 30, and the hydrogen sulfide gas concentration in the housing 20 is monitored by the hydrogen sulfide gas detection unit 40. Will be done.

Next, the control unit 90 compares the temperature of the all-solid-state battery cell 10 transmitted from the heat detection unit 30 with the threshold value (for example, 700 ° C.) (step S101). Here, when the temperature of all the all-solid-state battery cells 10 is less than the threshold value, the process returns to the start, and the heat detection unit 30 continues to monitor the temperature of each all-solid-state battery cell 10 to detect hydrogen sulfide gas. The monitoring of the hydrogen sulfide gas concentration in the housing 20 is continued by the unit 40.

On the other hand, when the temperature of one of the all-solid-state battery cells 10 is equal to or higher than the threshold value (in this example, it is assumed that an abnormality occurs in the all-solid-state battery cell 10 at the position N in FIG. 1 and the temperature rises beyond the threshold value. ), The control unit 90 compares the hydrogen sulfide gas concentration transmitted from the hydrogen sulfide gas detection unit 40 with the threshold value (step S103). Here, when the hydrogen sulfide gas concentration in the housing 20 is less than the threshold value, only the valve of the inert gas accommodating portion 30 is opened, and the gas outlet 80C closest to the all-solid-state battery cell 10 at the position N ( In this example, only the inert gas is injected into the housing 20 from the injection nozzle) (step S107). On the other hand, when the hydrogen sulfide gas concentration in the housing 20 is equal to or higher than the threshold value, both the valve of the inert gas accommodating portion 30 and the valve of the basic gas accommodating portion 40 are opened, and the all-solid-state battery cell at position N is opened. Both the inert gas and the basic gas are injected into the housing 20 from the gas outlet 80C closest to 10 (step S105; see the arrow in the gas flow path 70 in FIG. 1).

When the temperature of the all-solid-state battery cell 10 and the concentration of hydrogen sulfide gas decrease and the abnormality disappears, the process returns to the start, the monitoring of the temperature of the all-solid-state battery cell 10 is continued, and the hydrogen sulfide gas detection unit 40 inside the housing 20. Monitoring of hydrogen sulfide gas concentration will be continued.

According to the all-solid-state battery pack 100 described above, the basic material can be stored in the basic gas accommodating portion 60 different from the portion accommodating the all-solid-state battery cell 10 (that is, the inside of the housing 20). Further, since the basic gas can be introduced into the housing 20 in which the all-solid-state battery cell 10 is housed only when the hydrogen sulfide gas is generated, the hydrogen sulfide gas can be effectively neutralized and the base in the normal state can be introduced. It is possible to suppress corrosion of battery components due to sex materials. At this time, by adjusting the injection amount of the basic gas (for example, by making it approximately the same molar as hydrogen sulfide gas), the amount of the excess basic gas can be minimized, and the all-solid-state battery cell can be used. It is also possible to minimize the corrosion of the battery components due to the basic material at the time of the abnormality of 10. In addition, by ejecting an inert gas when an abnormality occurs in the all-solid-state battery cell 10, the reaction that occurs when the all-solid-state battery cell 10 is abnormal can be suppressed, thereby suppressing the generation of high-temperature gas. The resulting heat propagation can be suppressed. At this time, since the all-solid-state battery pack 100 includes a plurality of gas injection ports 80, the inert gas and the basic gas can be efficiently injected into the all-solid-state battery cell 10 in which the abnormality has occurred.

The all-solid-state battery pack 100 can be used for various purposes. Specific applications include portable power supplies for personal computers, portable electronic devices, mobile terminals, etc .; power supplies for driving vehicles such as electric vehicles (EVs), hybrid vehicles (HVs), and plug-in hybrid vehicles (PHVs); small power storage devices. Such as a storage battery, and among them, a vehicle driving power source is preferable.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

10 All-solid-state battery cell 20 Housing 30 Heat detection unit 40 Hydrogen sulfide gas detection unit 50 Inactive gas storage unit 60 Basic gas storage unit 70 Gas flow path 80 Outlet 90 Control unit 100 All-solid-state battery pack

Claims (1)

With multiple all-solid-state battery cells arranged,
A housing for accommodating the plurality of all-solid-state battery cells,
A heat detection unit arranged in the housing and detecting the temperature of the plurality of all-solid-state battery cells,
A hydrogen sulfide gas detector, which is arranged in the housing and detects the concentration of hydrogen sulfide gas,
The inert gas housing and
Basic gas housing and
A plurality of gas outlets for ejecting the inert gas from the inert gas accommodating portion and the basic gas from the basic gas accommodating portion into the housing.
Is an all-solid-state battery pack that contains
The all-solid-state battery cell includes a positive electrode, a negative electrode, and a sulfide-based solid electrolyte.
When the temperature of the all-solid-state battery cell rises above the threshold value, an inert gas is ejected from the gas outlet closest to the all-solid-state battery cell whose temperature has risen, and the concentration of the hydrogen sulfide gas exceeds the threshold value. It is configured to eject a basic gas in addition to an inert gas when it rises.
All-solid-state battery pack.

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