JP6933071B2 - Battery system - Google Patents

Description

The present disclosure relates to a battery module mounted on a vehicle or the like.

In each of the plurality of cells included in the battery module, the inside of the cell generates excessive heat due to an abnormality such as overcharging or an internal short circuit, and gas may be generated in the cell due to this heat generation. When a large amount of this gas (hereinafter, also referred to as “smoke gas”) is generated, the internal pressure of the cell increases. In order to suppress this increase in internal pressure, some cell cells are provided with an exhaust unit for discharging the internal gas to the outside. Since the gas discharged from the inside of the cell to the outside through the exhaust part contains flammable substances, it is desirable not to generate heat by reacting with oxygen.

Japanese Unexamined Patent Publication No. 2014-33824 (Patent Document 1) discloses a battery system in which a fire extinguishing container is provided on the outside of a battery module including a plurality of cell cells. In this battery system, when smoke gas is discharged from the cell, the fire extinguishing agent in the fire extinguishing container is ejected to the battery module. The extinguishing agent ejected into the battery module suppresses the heat generation of the smoked gas.

Japanese Unexamined Patent Publication No. 2014-33824

In a battery system installed in a vehicle equipped with a secondary battery such as an electric vehicle, it is desired to detect the generation of smoked gas in addition to suppressing the heat generation of smoked gas when an abnormality occurs in the battery module. It is rare. This is to perform control such as stopping the energization of an abnormal battery module that has generated fuming gas.

As a means for detecting the generation of smoked gas, for example, a temperature sensor is provided in the exhaust passage of the smoked gas, and when the temperature detected by the temperature sensor exceeds the reference temperature, it is possible to detect that the smoked gas is generated. Conceivable. However, if the extinguishing agent is ejected into the exhaust passage along with the generation of the fuming gas, the fuming gas is mixed with the extinguishing agent and the temperature of the fuming gas drops. Therefore, even though the smoked gas is generated, the temperature detected by the temperature sensor does not exceed the reference temperature, and the generation of the smoked gas may not be detected accurately.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a battery module capable of detecting the generation of smoked gas while suppressing heat generation of smoked gas.

The battery module according to the present disclosure includes a plurality of single batteries each having an exhaust unit for discharging smoke gas from the inside to the outside, and an exhaust gas which is communicated with each of the exhaust parts and the exhaust gas discharged from the exhaust part flows. It is provided with a passage and a fire extinguishing container provided in the exhaust passage. The fire extinguishing container contains a fire extinguishing agent and a fire extinguishing mixture containing a material having a lower heat generation and a lower specific heat than the smoke gas, and is broken by the heat of the smoke gas to eject the fire extinguishing mixture into the exhaust passage. ..

According to the above configuration, the fire extinguishing container is arranged in the exhaust passage through which the fuming gas flows. The fire extinguishing container contains a fire extinguishing mixture in which a fire extinguishing agent and a material having a lower heat generation and a lower specific heat than the fuming gas (hereinafter, also referred to as "low specific heat material") are mixed. When the fire extinguishing container is broken by the heat of the smoke gas and the fire extinguishing mixture is ejected, the extinguishing agent contained in the fire extinguishing mixture suppresses the heat generation of the extinguishing gas. On the other hand, the heat of the fuming gas before the heat generation is suppressed by the fire extinguishing agent is transferred to the low specific heat material at an early stage. Therefore, the decrease in the temperature of the gas after the fuming gas, the fire extinguishing agent, and the low specific heat material are mixed is suppressed.

Therefore, when a temperature sensor is provided in the exhaust passage of the smoked gas to detect the generation of the smoked gas, by using the fire extinguishing mixture, the smoke generated by the temperature sensor is compared with the case where only the fire extinguishing agent is used. It is possible to suppress a decrease in the temperature of the gas. As a result, the generation of fuming gas can be detected with high accuracy.

According to the present disclosure, it is possible to provide a battery module capable of detecting an abnormality of the battery module while suppressing heat generation of fuming gas.

It is a figure which shows typically the structure of the battery system which concerns on this embodiment. It is a perspective view which shows the negative electrode side of a cell. It is a figure which showed the experimental result in the comparative example and this embodiment. It is a flowchart of the battery system in this embodiment.

Hereinafter, the present embodiment will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

In the present embodiment, an example in which the battery module 1 according to the present embodiment is mounted on a hybrid vehicle, an electric vehicle, or the like will be described.

FIG. 1 is a diagram schematically showing a configuration of a battery system 11 according to the present embodiment. The battery system 11 includes a battery module 1, a fan 80, a supply duct 90, an exhaust passage 70, an ECU 200, and a temperature sensor 110.

The battery module 1 includes a plurality of cell cells 2, a battery case 30, a battery holder 40, an upper lid 50, and a fire extinguishing container 100.

Each of the plurality of cell cells 2 is a rechargeable secondary battery. Examples of the cell 2 include a nickel-metal hydride battery and a lithium-ion battery. In FIG. 1, a positive electrode 10 is formed at the upper end of the cell 2 and a negative electrode 20 is formed at the lower end of the cell 2.

FIG. 2 is a perspective view showing the negative electrode side of the cell 2. The cell 2 includes a peripheral wall portion 22 and a lower wall portion 23. A negative electrode 20 and an exhaust portion 21 are formed on the lower wall portion 23.

The exhaust portion 21 is formed by providing a notch groove 24 in the lower wall portion 23. When the internal pressure becomes equal to or higher than a predetermined pressure due to the internal gas generated by the heat generation of the cell 2 (hereinafter, also referred to as “smoke gas G”), the cut groove 24 is broken. Then, the fuming gas G is discharged from the broken portion, and the internal pressure of the cell 2 is lowered. Although FIG. 2 shows an example in which the shape of the exhaust portion 21 is circular, it may be a shape other than circular. For example, it may have an elliptical or polygonal shape. Further, in the present embodiment, an example in which a cylindrical battery is adopted as the cell 2 will be described, but a square battery may be used.

Returning to FIG. 1, the battery module 1 includes a battery case 30 and an upper lid 50, and the upper surface of the battery case 30 is sealed by the upper lid 50. Each of the plurality of cell cells 2 is held in the battery holder 40 and housed in the battery case 30 and the upper lid 50. The battery case 30 is formed with an exhaust passage 150 communicating with an exhaust unit 21 provided in each of the plurality of cell cells 2.

The exhaust passage 150 is a passage through which the smoke gas G discharged from the exhaust portion 21 of the cell 2 flows. The exhaust passage 150 includes an inflow space 151 and an integrated space 152. The inflow space 151 is a space into which the smoke gas G discharged from each of the exhaust portions 21 of the plurality of cell cells 2 flows into the inflow space 151. The inflow space 151 communicates with each exhaust unit 21 of the plurality of cell cells 2.

The integrated space 152 is located downstream of the inflow space 151 in the flow direction D of the fuming gas G. In the aggregation space 152, the smoke gas G discharged from each exhaust unit 21 is aggregated.

The fire extinguishing container 100 is arranged on the downstream side of the inflow space 151 in the flow direction D of the fuming gas G. Specifically, the fire extinguishing container 100 is arranged in the centralized space 152 of the exhaust passage 150. The fire extinguishing container 100 contains a fire extinguishing agent.

The fire extinguishing container 100 includes a case body and a thin film portion. For example, the case body is formed with an opening that opens upward in FIG. 1, and the thin film portion is arranged so as to close the opening. The thin film portion is formed to have a thinner film thickness than the case body. The fire extinguishing agent is housed in the space closed by the case body and the thin film part.

One end of the exhaust passage 150 communicates with the exhaust passage 70. The exhaust passage 70 communicates with an exhaust duct (not shown). The exhaust duct communicates with the outside of the vehicle on which the battery module 1 is mounted. The other end of the exhaust passage 150 communicates with a supply duct 90 provided with a fan 80. When the fan 80 is operated, the air in the vehicle interior is supplied from the supply duct 90 into the exhaust passage 150.

The smoke gas G flowing through the exhaust passage 150 is circulated by the fan 80 in the direction of the flow direction D of the smoke gas G shown in FIG.

The temperature sensor 110 is provided in the exhaust passage 70 in the present embodiment. The temperature sensor 110 detects the temperature Ts in the exhaust passage 70 and outputs it to the ECU 200 (Electronic Control Unit).

The ECU 200 uses the temperature Ts output from the temperature sensor 110 to determine whether or not an abnormality has occurred in the plurality of cell cells 2 included in the battery module 1. Specifically, if the detected temperature Ts is equal to or higher than the reference temperature Tref, the ECU 200 determines that the smoke gas G is discharged from any of the plurality of cell cells 2 included in the battery module 1. do. If the detected temperature Ts is less than the reference temperature Tref, the ECU 200 determines that the fuming gas G is not discharged from any of the plurality of cell cells 2 included in the battery module 1. The ECU 200 controls the battery module 1, which will be described later, according to the determination result. The reference temperature Tref is a temperature for detecting that the smoke gas G is generated, and is set to a temperature equal to or higher than a temperature at which the fire extinguishing container 100 can be broken.

In the battery system 11 configured as described above, when an abnormality occurs in the battery module 1, it is desired to detect the generation of the smoke gas G while suppressing the heat generation of the smoke gas G.

When an abnormality such as overcharging or an internal short circuit occurs in any of the plurality of cell 2 included in the battery module 1, a large amount of fuming gas G is generated inside the cell 2 and the internal pressure in the cell 2 is increased. May rise. When the internal pressure in the cell 2 becomes equal to or higher than a predetermined pressure, the smoke gas G is discharged from the exhaust portion 21 of the cell 2. The fuming gas G may contain flammable substances. Further, the temperature of the fuming gas G is high, for example, about several hundred degrees.

When the smoke gas G is discharged, the heat of the discharged smoke gas G breaks the fire extinguishing container 100 arranged in the centralized space 152, and the fire extinguishing agent is ejected.

The ejected fire extinguishing agent fills the aggregation space 152 and mixes with the fuming gas G discharged from the cell 2. As a result, oxygen is prevented from being supplied to the smoke gas G, and the heat generation of the smoke gas G is suppressed.

However, there is a possibility that the temperature of the smoke gas G is lowered by mixing the smoke gas G and the fire extinguishing agent. Therefore, even though the smoke gas G is generated, the temperature Ts detected by the temperature sensor 110 does not exceed the reference temperature Tref, and there is a possibility that the generation of the smoke gas G cannot be detected accurately.

Therefore, in the present embodiment, a mixed fire extinguishing agent in which a fire extinguishing agent and a material having a lower heat generation and a lower specific heat than the smoke gas G (hereinafter, also referred to as “low specific heat material”) is stored in the fire extinguishing container 100. .. Hereinafter, an example in which argon is used as the low specific heat material will be described.

When the fire extinguishing container 100 arranged in the aggregation space 152 is broken by the heat of the smoke gas G and the fire extinguishing mixture is ejected, the ejected fire extinguishing mixture fills the aggregation space 152 and the cell 2 It is mixed with the fuming gas G discharged from. Then, the fire extinguishing agent contained in the fire extinguishing mixture prevents oxygen from being supplied to the smoke gas G, and suppresses the heat generation of the smoke gas G.

On the other hand, the fire extinguishing mixture contains argon. Since argon has low heat generation, it is very unlikely to generate heat. The exothermic property indicates, for example, the degree of easiness of self-heating, such as reacting with oxygen to generate heat. Further, since argon is a material having a lower specific heat than the smoke gas G, when the fire extinguishing mixture is ejected to the smoke gas G, the heat of the smoke gas G before the heat generation is suppressed by the fire extinguishing agent becomes argon at an early stage. Heat is transferred to. Therefore, the decrease in temperature of the gas (hereinafter, also referred to as “post-fire extinguishing gas”) after the fuming gas G, the fire extinguishing agent, and argon are mixed is suppressed.

After extinguishing the fire, the gas flows from the centralized space 152 to the exhaust passage 70 and is discharged to the outside of the vehicle through the exhaust duct. In the exhaust passage 70, the temperature Ts is detected by the temperature sensor 110 provided in the exhaust passage 70 and output to the ECU 200. Then, the ECU 200 determines the state of the battery module 1 using the temperature Ts output from the temperature sensor 110.

As described above, since the decrease in the temperature of the gas after extinguishing the fire is suppressed, the temperature Ts detected by the temperature sensor 110 can be maintained at a temperature equal to or higher than the reference temperature Tref.

Therefore, when the fire extinguishing mixture is ejected, the temperature sensor 110 can detect the temperature Ts of the post-fire extinguishing gas flowing through the exhaust passage 70 as a temperature equal to or higher than the reference temperature Tref.

FIG. 3 is a diagram showing the experimental results of the comparative example and the present embodiment. A comparative example is a case where the fire is extinguished only with a fire extinguishing agent without mixing argon. The present embodiment is a case where the fire is extinguished with a fire extinguishing mixture in which argon (Ar) is mixed with the fire extinguishing agent.

In both the comparative example and the present embodiment, the initial temperature of the fuming gas G was Tf. In the comparative example, when the extinguishing agent is ejected to the smoking gas G, the extinguishing agent suppresses the heat generation of the smoking gas G. Then, the temperature Ts detected by the temperature sensor 110 is lowered to the temperature T1 (T1 <Tf). The temperature T1 is lower than the reference temperature Tref (T1 <Tref). Therefore, although the smoke gas G is generated, the abnormality of the battery module 1 is not detected.

In the present embodiment, when the fire extinguishing mixture is ejected to the smoke gas G, the extinguishing agent contained in the fire extinguishing mixture suppresses the heat generation of the smoke gas G. On the other hand, when the fire extinguishing mixture is ejected to the smoke gas G, the heat of the smoke gas G before the heat generation is suppressed by the fire extinguishing agent is transferred to argon at an early stage. Due to this effect, the temperature of the gas after extinguishing the fire is suppressed from decreasing.

Therefore, the temperature Ts detected by the temperature sensor 110 is lowered to the temperature T2, but the temperature T2 is higher than the temperature T1 (T1 <T2 <Tf). The temperature T2 is higher than the reference temperature Tref (T2> Tref), and it is detected that the fuming gas G is generated.

The initial temperature Tf of the fuming gas G is, for example, about several hundred degrees Celsius. The temperature T1 is, for example, about several degrees Celsius to several tens of degrees Celsius. The temperature T2 is, for example, a temperature higher than the temperature T1 by about several tens of degrees Celsius. As described above, the reference temperature Tref is an arbitrarily set temperature, but is set to a temperature equal to or higher than the temperature at which the fire extinguishing container 100 can be broken.

FIG. 4 is a flowchart of the battery system 11 according to the present embodiment. The processes shown in this flowchart are repeatedly executed at predetermined intervals.

The ECU 200 acquires the temperature Ts detected by the temperature sensor 110 (step 10, hereinafter the step is abbreviated as “S”). The ECU 200 compares the temperature Ts acquired in S10 with the reference temperature Tref (S20).

In S20, when the ECU 200 determines that the temperature Ts is lower than the reference temperature Tref (NO in S20), the smoke gas G is not generated and the battery module 1 is determined to be in a normal state (S30). Then, the ECU 200 sets the control mode of the battery module 1 to the first control mode (S40). The first control mode is a mode in which the battery module 1 performs control normally performed in a normal state.

In S20, when the ECU 200 determines that the temperature Ts is equal to or higher than the reference temperature Tref (YES in S20), the smoke gas G is generated, and the battery module 1 determines that the battery module 1 is in an abnormal state (S50). Then, the ECU 200 sets the control mode of the battery module 1 to the second control mode (S60). The second control mode is, for example, a mode in which control is performed so as to limit the use of the abnormal battery module 1. When the second control mode is selected, the ECU 200 performs control such as stopping the energization so that the abnormal battery module 1 cannot be used, and ends the process.

In S20, the state of the battery module 1 was determined by comparing the temperature Ts with the reference temperature Tref, but the state of the battery module 1 was determined by comparing the temperature Ts with the reference temperature Tref and the time during which the state was maintained. May be determined. Specifically, for example, when it is determined that the temperature Ts is equal to or higher than the reference temperature Tref and the state in which the temperature Ts is equal to or higher than the reference temperature Tref continues for a predetermined time or longer, the ECU 200 generates smoke gas G. Therefore, it is determined that the battery module 1 is in an abnormal state.

This makes it possible to prevent erroneous detection. The predetermined time is, for example, about several seconds to several tens of seconds.

As described above, in the present embodiment, the fire extinguishing mixture containing a mixture of the fire extinguishing agent and argon, which is a material having a lower heat generation and a lower specific heat than the fuming gas G, is stored in the fire extinguishing container 100 and exhausted. It was placed in the passage 150. When the fire extinguishing mixture is ejected to the smoke gas G, the heat of the smoke gas G is suppressed by the fire extinguishing agent contained in the fire extinguishing mixture, and the heat of the smoke gas G before the heat generation is suppressed by the fire extinguishing agent is suppressed. Early heat transfer to argon. Due to this effect, it is suppressed that the temperature of the gas is lowered after the fire is extinguished. Therefore, even after the fire extinguishing mixture is ejected into the smoke gas G, the temperature sensor 110 provided in the exhaust passage 70 can accurately detect the abnormality of the battery module 1.
<Modification example>
In the present embodiment, the fire extinguishing container 100 is arranged in the central space 152 of the exhaust passage 150 on the downstream side of the flow direction D of the smoke gas G, and the temperature sensor 110 is provided in the exhaust passage 70. The position where the fire extinguishing container 100 and the temperature sensor are provided is not particularly limited. It suffices if the extinguishing mixture is ejected to suppress the heat generation of the smoke gas G and the abnormality of the battery module 1 can be detected. For example, the fire extinguishing container 100 and the temperature sensor 110 are arranged at any position in the exhaust passage 150 without specifying the flow direction D of the smoke gas G. The volume fraction of the fire extinguishing mixture contained in the fire extinguishing container 100 when vaporized may be calculated so that the exhaust passage 150 is filled with the fire extinguishing mixture when it is ejected.

When the exhaust passage 150 is filled with the fire extinguishing mixture, the fire extinguishing agent suppresses the heat generation of the smoke gas G, and the heat of the smoke gas G before the heat generation is suppressed is transferred to argon. An abnormality in the battery module 1 can be detected by detecting the temperature of the gas after extinguishing the fire after being thermally transferred to argon by the temperature sensor 110.

Further, in the present embodiment, an example in which one fire extinguishing container 100 is arranged is shown, but the number of arranged fire extinguishing containers 100 is not limited to one, and even if a plurality of fire extinguishing containers 100 are arranged. good.

Further, the temperature sensor 110 may be provided in the smoke exhaust duct. When a plurality of battery modules 1 are mounted on a vehicle, one temperature sensor 110 can detect an abnormality of the plurality of battery modules 1.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present disclosure is shown by the scope of claims rather than the description of the embodiment described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Battery module, 2 Single battery, 10 Positive electrode, 11 Battery system, 20 Negative electrode, 21 Exhaust part, 22 Peripheral wall part, 23 Lower wall part, 24 Notch groove, 30 Battery case, 40 Battery holder, 50 Top lid, 70,150 Exhaust Passage, 80 fan, 90 supply duct, 100 fire extinguishing container, 110 temperature sensor, 151 inflow space, 152 centralized space, 200 ECU, D flow direction, G smoke gas, T1, T2, Ts temperature, Tf initial temperature, Tref reference temperature ..

Claims (3)

A plurality of single batteries each having an exhaust part that discharges smoked gas from the inside to the outside,
An exhaust passage that communicates with each of the exhaust units and allows the smoked gas discharged from the exhaust unit to flow through the exhaust passages.
And fire extinguishing container provided in the exhaust passage,
A temperature sensor that detects the temperature in the exhaust passage and
It is equipped with a control device that detects the generation of the smoked gas.
The fire extinguishing container contains a fire extinguishing agent and a fire extinguishing mixture containing argon , is broken by the heat of the fuming gas, and ejects the fire extinguishing mixture into the exhaust passage .
The control device detects the generation of the fuming gas when the detection temperature of the temperature sensor is equal to or higher than the reference temperature.
The battery system, wherein the reference temperature is a temperature equal to or higher than the temperature at which the fire extinguishing container is broken. The battery system according to claim 1, wherein when the generation of the fuming gas is detected, the control device limits the use of the plurality of cell cells. The exhaust passages are located in an inflow space into which the smoked gas discharged from the exhaust portion of each of the plurality of cells flows, and on the downstream side of the inflow space in the flow direction of the smoked gas. Including a centralized space in which the smoked gas discharged from the exhaust portion of each of the cells of the above is collected.
The battery system according to claim 1 or 2, wherein the temperature sensor is provided on the downstream side of the fire extinguishing container in the distribution direction and on the downstream side of the centralized space in the distribution direction.

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