JP2009238654A - Battery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cool a unit cell irrespective of a state of a power supply system or a control system of a vehicle side. <P>SOLUTION: In a battery device 10 with a unit cell 24 housed in a battery case 16, a heat exchanger 52 connected to a coolant tank 50 with noncombustible refrigerant stored is fitted at a part exposed in combustion gas generated from the unit cell 24 in the battery case 16, an expansion valve 54 to the heat exchanger 52 and a pressure valve 56 opening with a preset coolant pressure P0 are connected in order, then, the pressure valve 56 is opened with the heating of the combustion gas of the heat exchanger 52, and the coolant to be expanded by decompression at the expansion valve 54 is injected in the battery case 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery device suitable for being mounted on a hybrid vehicle or an electric vehicle.

Hybrid vehicles and electric vehicles that use an electric motor as a drive source are equipped with a high-voltage battery device for driving the electric motor. In this type of battery device, when the ambient temperature rises to a high temperature, for example, in the summer, the self-discharge of the built-in unit cell may become intense and generate heat. As described above, when the amount of generated heat increases in an environment where the temperature is very high, the unit cell may run out of heat, and a very high-temperature combustion gas may be ejected from the unit cell. In particular, a high-voltage battery device for driving an automobile uses a large number of large-capacity unit cells. Therefore, the amount of heat generated by self-discharge at a high temperature is extremely large, and the probability of thermal runaway increases.
Therefore, conventionally, an abnormality detecting means for detecting an abnormality such as breakage of the case of the battery device or liquid leakage of the unit cell, and an apparatus for injecting the coolant into the battery case when the abnormality signal is issued. Has been proposed (see, for example, Patent Document 1).
JP-A-9-74603

However, since the conventional system is configured to generate an abnormality due to an electrical signal, when the power of the power system on the vehicle side is cut off due to damage to the battery device or an electrical failure occurs in the control system In this case, the safety device cannot operate without an abnormal signal being issued.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a battery device that can cool a unit cell regardless of the state of a power supply system or a control system on the vehicle side.

  In order to achieve the above object, according to the present invention, in a battery device in which a unit cell is housed in a battery case, a non-flammable refrigerant is provided in a location exposed to the combustion gas generated from the unit cell in the battery case. A refrigerant tank stored or a heat exchanger connected to the refrigerant tank is provided, and a pressure reducing device and a pressure valve opened at a predetermined refrigerant pressure are sequentially connected to the refrigerant tank or the heat exchanger, the refrigerant tank, Alternatively, the pressure valve opens as the heat exchanger heats with the combustion gas, and the refrigerant decompressed and expanded by the decompression device is injected into the battery case.

  According to the present invention, in the battery device described above, a safety valve for injecting the combustion gas is provided in a case body of the unit cell, and a plurality of the unit cells are disposed in the battery case on a side where the safety valve is disposed. The refrigerant tank or the heat exchanger is extended so as to be aligned in one direction and opposed to the safety valve of each unit cell.

  Further, the present invention is characterized in that, in the above battery device, the battery case has a sealed structure and has an exhaust valve that opens when the internal pressure reaches a predetermined pressure and communicates inside and outside.

According to the present invention, when high-temperature combustion gas is generated from a unit cell stored in a battery case due to thermal runaway or the like, the pressure valve is opened along with the generation of the combustion gas, and the refrigerant is expanded by being decompressed by the decompression device. Is automatically injected into the battery case, so that the unit cell can be quickly cooled when combustion gas is generated.
In addition, since the pressure valve is operated by heat exchange between the combustion gas and the refrigerant, even if a problem occurs in the power supply system or control system on the vehicle side, it does not depend on the state of these power supply systems or control systems. The unit cell can be cooled by operating the pressure valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a diagram showing a configuration of a four-wheeled electric vehicle 1 equipped with a battery device 10 according to the present embodiment. The electric vehicle 1 includes a front wheel 2 and a rear wheel 3, and a vehicle driving motor 4 provided on each of the front wheel 2 and the rear wheel 3 or both (the illustrated example is only the front wheel 2). Yes. The vehicle drive motor 4 constitutes a drive source for moving the vehicle. In addition, a driver's seat 6 and a rear seat 7 are disposed in the front and rear of the passenger compartment 5 of the electric vehicle 1, and a handle 8 and a meter panel (not shown) are disposed in front of the driver's seat 6.
A trunk 9 is provided behind the rear seat 7, and a high-voltage battery device 10 is disposed in the trunk 9. The battery device 10 is driven by supplying power to the vehicle drive motor 4, and power is transmitted to the vehicle drive motor 4 through a high electric wire 11 as a power supply line drawn from the battery device 10.

  Here, when the battery of the battery device 10 (the assembled battery 18 described later) is used only for driving the electric vehicle 1, the battery is discharged including spontaneous discharge. In order to compensate for this discharge, when the electric vehicle 1 is decelerated by switching control, the vehicle driving motor 4 can be used as a generator, and a regenerative brake that uses kinetic energy for supplementary charging of the battery can be used. Therefore, the battery device 10 of the present embodiment is configured to be able to supply and receive power to the vehicle drive motor 4 in both directions.

FIG. 2 is a diagram schematically illustrating the configuration of the battery device 10.
The battery device 10 is configured by housing an assembled battery 18 that stores power to be supplied to the vehicle driving motor 4 in a sealed battery case 16 having a container body 12 and a cover plate 14. Furthermore, the battery device 10 includes a normal cooling mechanism 20 that performs normal cooling of the assembled battery 18 and an abnormal cooling mechanism 22 that automatically cools the assembled battery 18 in the event of an abnormality.

  The assembled battery 18 includes a plurality of unit cells (cells) 24 assembled and electrically connected to each other. The unit cell 24 includes a power generation element in which a positive electrode and a negative electrode are wound via a separator. As shown in FIG. 3, the non-aqueous electrolyte secondary battery containing aluminum is accommodated in a rectangular plate-like case body 26 made of aluminum or an aluminum alloy. Positive and negative electrodes 28 are respectively provided on the side, and a safety valve 30 is provided substantially at the center of the upper surface 26A.

  As the non-aqueous electrolyte secondary battery, for example, a lithium ion secondary battery is preferably used. Lithium ion secondary batteries, etc., especially when overcharged or short-circuited inside the battery, generate heat and generate heat, and the internal pressure rises rapidly due to the generation of high-temperature combustion gas inside the case. There are things to do. As described above, when the internal pressure of the case body 26 suddenly increases, the safety valve 30 is opened by the internal pressure, and the internal combustion gas is ejected to the outside. Thereby, since the internal pressure escapes to the outside, the rupture of the case body 26 when the thermal runaway occurs is prevented.

  In addition, when combustion gas is injected from the unit cell 24, the internal pressure of the battery case 16 may increase and burst. Therefore, even in such a case, the battery case 16 is provided with an exhaust safety valve 32 in order to prevent the battery case 16 from bursting. When the internal pressure of the battery case 16 reaches a predetermined internal pressure, the exhaust safety valve 32 is opened by pushing the plug by the internal pressure and releasing the gas inside the battery case 16 to the outside. 16 rupture is prevented. The exhaust safety valve 32 is configured to discharge the combustion gas toward the outside of the vehicle in order to prevent the combustion gas from entering the passenger compartment 5.

The normal cooling mechanism 20 is for cooling each unit cell 24 of the assembled battery 18 and maintaining a temperature at which good charge / discharge efficiency can be realized. The cooling plate 40 and the refrigerant circulation pipes 42A and 42B are connected to each other. I have.
The cooling plate 40 is formed in the shape of a long plate made of aluminum or aluminum alloy, and refrigerant circulation pipes 42A and 42B are drawn out from one end thereof. For example, a refrigerant of an air conditioner (car air conditioner) already installed in the electric vehicle 1 is introduced into the refrigerant circulation pipes 42A and 42B.
The cooling plate 40 is disposed in close contact with the bottom surface 16A of the battery case 16 from the outside, and cools the assembled battery 18 disposed inside the battery case 16 by heat conduction through the bottom surface 16A.

The abnormal cooling mechanism 22 rapidly cools the unit cell 24 when combustion gas is ejected from the unit cell 24 due to thermal runaway or the like, and is expanded as a refrigerant tank 50, a heat exchanger 52, and a decompression device. A valve 54 and a pressure valve 56 are provided.
The refrigerant tank 50 is a storage tank that stores refrigerant, and is arranged in parallel outside the battery case 16, and a refrigerant pipe 51 that forms a refrigerant introduction path is drawn into the battery case 16. The heat exchanger 52, the expansion valve 54, and the pressure valve 56 are sequentially provided. The refrigerant stored in the refrigerant tank 50 is used to cool the unit cell 24 that has injected the combustion gas. Therefore, the refrigerant, for example, incombustible refrigerant such as CO ₂ refrigerant is used.

In the battery case 16, each unit cell 24 is arranged side by side so that the safety valve 30 is positioned above, and the heat exchanger 52 extends so as to face the safety valve 30 of each unit cell 24. When a high-temperature combustion gas is ejected from any of the unit cells 24, the combustion gas and the refrigerant in the refrigerant pipe 51 exchange heat with the heat exchanger 52, and the refrigerant is heated.
The expansion valve 54 depressurizes and expands the refrigerant flowing from the heat exchanger 52 and flows it toward the pressure valve 56. The pressure valve 56 is provided at the end of the refrigerant pipe 51 and has a refrigerant pressure equal to or higher than a predetermined value. And the expanded refrigerant is injected into the battery case 16.

The opening of the pressure valve 56 will be described. When the refrigerant in the refrigerant pipe 51 is heated by the heat exchange with the combustion gas and the temperature of the refrigerant rises, the pressure valve is proportional to the temperature rise as shown in FIG. The refrigerant pressure at 56 also increases.
Therefore, the refrigerant temperature T0 reached when the refrigerant is heated by heat exchange with the combustion gas, and the refrigerant pressure P0 at the pressure valve 56 at this temperature T0 are obtained in advance by experiments or the like, and the refrigerant pressure When the pressure reaches the pressure P0 (or a pressure lower than the pressure P0 by a predetermined margin), the pressure valve 56 is opened. As a result, as shown in FIG. 5, when the gas of the unit cell 24 is generated, the pressure valve 56 is quickly opened, the expanded refrigerant gas is injected into the battery case 16, and the unit cell 24 is cooled.

A series of operations when such a thermal runaway occurs will be described in more detail with reference to FIG.
As shown in FIG. 6, when any unit cell 24 of the assembled battery 18 is thermally runaway (step S1), the safety valve 30 is opened due to the generation of combustion gas in the case body 26 of the unit cell 24 (step S1). S2) High-temperature combustion gas is ejected into the battery case 16 (step S3). Thereby, the heat exchanger 52 arrange | positioned above the safety valve 30 of the unit cell 24 is exposed to a high temperature combustion gas, and is heated (step S4).

  As a result of heating the heat exchanger 52, the temperature of the refrigerant in the refrigerant pipe 51 rises, the refrigerant pressure increases (step S5), and the pressure valve 56 opens (step S6). Thereby, the refrigerant gas decompressed and expanded by the expansion valve 54 is injected from the pressure valve 56 into the battery case 16 (step S7). As a result, the unit cell 24 that has generated heat due to thermal runaway is quickly cooled by the refrigerant gas, so that the thermal runaway of the unit cell 24 stops, and the other unit cell 24 also undergoes thermal runaway due to heat generation during the thermal runaway. It can also be prevented from being caused in a chain.

  When the refrigerant gas is injected from the pressure valve 56, the refrigerant is introduced into the heat exchanger 52 from the refrigerant tank 50 and the temperature of the heat exchanger 52 decreases as the refrigerant is depressurized by the expansion valve 54. However, while the combustion gas is generated from the unit cell 24 (step S8), heat is absorbed from the combustion gas (step S9), and the refrigerant pressure is increased (step S5). To do. When the thermal runaway of the unit cell 24 is stopped by the cooling of the refrigerant gas and the generation of the combustion gas is stopped, the heating in the heat exchanger 52 is also stopped, so that the injection of the refrigerant gas is automatically stopped.

Further, when the refrigerant gas is injected into the battery case 16, the internal pressure of the battery case 16 rises, so the exhaust safety valve 32 provided in the battery case 16 is opened, and the refrigerant gas together with the combustion gas. Is discharged out of the battery case 16 (step S10).
As described above, since the non-combustible gas refrigerant such as CO ₂ is used as the refrigerant gas, when the safety valve 32 for exhaust is opened, the air in the battery case 16 is pushed out with the injection of the refrigerant gas. Thus, the refrigerant gas is filled in the battery case 16. As a result, since oxygen in the battery case 16 becomes lean, if combustion occurs in the battery case 16, the combustion is extinguished quickly.

As described above, according to the present embodiment, when high-temperature combustion gas is generated from the unit cell 24 stored in the battery case 16 due to thermal runaway or the like, the pressure valve 56 is opened along with the generation of the combustion gas, and the expansion is performed. Since the refrigerant gas decompressed and expanded by the valve 54 is automatically injected into the battery case 16, the unit cell 24 can be quickly cooled when high-temperature combustion gas is generated from the unit cell 24. it can. This also prevents thermal runaway from being chained between the unit cells 24.
In addition, since the pressure valve 56 is operated by heat exchange between the combustion gas and the refrigerant, even if a trouble occurs in the power supply system or control system on the vehicle side, it depends on the state of the power supply system or control system. Accordingly, the unit cell 24 can be cooled by operating the pressure valve 56.

  Furthermore, since the refrigerant is heated by increasing the pressure by heat exchange with the combustion gas and the pressure of the refrigerant is increased, the combustion gas is generated even if the pressure of the refrigerant tank 50 is reduced by the refrigerant injection. As long as the refrigerant pressure is continuously increased, the injection of the refrigerant can be continued. Thereby, in spite of combustion gas being generated, the injection of the refrigerant does not stop as the pressure in the refrigerant tank 50 decreases.

  Further, according to the present embodiment, since the heat exchanger 52 is extended so as to face the safety valve 30 of each of the plurality of unit cells 24, no matter which unit cell 24 generates combustion gas, heat exchange is performed. The vessel 52 can be exposed to the combustion gas, and cooling with a refrigerant can be performed.

  Further, according to the present embodiment, since the battery case 16 is provided with the exhaust safety valve 32 that opens when the internal pressure reaches a predetermined pressure and communicates the inside and the outside, the combustion gas and the refrigerant gas are injected. By opening the exhaust safety valve 32 and pushing out the air inside, the battery case 16 can be filled with nonflammable refrigerant gas. Thereby, when combustion has occurred in the battery case 16, it can be extinguished quickly.

Second Embodiment
FIG. 7 is a diagram schematically showing the configuration of the battery device 110 according to the second embodiment of the present invention. In addition, in the same figure, the same code | symbol is attached | subjected about what was demonstrated in 1st Embodiment, and the description is abbreviate | omitted.
As shown in this figure, in the battery device 110 of the present embodiment, the refrigerant tank 150 is opposed to the safety valve 30 of each unit cell 24 in the battery case 16 instead of the abnormal cooling mechanism 122 having the heat exchanger 52. When any combustion cell is generated from any of the unit cells 24, it is exposed to the combustion gas. The casing of the refrigerant tank 150 is made of a material having heat conductivity that can sufficiently exchange heat with the combustion gas, and the refrigerant in the refrigerant tank 150 is heated as the combustion gas is generated. Refrigerant is injected from the pressure valve 56 through the expansion valve 54.

  As described above, according to this embodiment, the same effect as that of the first embodiment can be obtained, and further, since the refrigerant tank 150 is provided in the battery case 16, it is necessary to draw out the refrigerant pipe 51 from the battery case 16. Therefore, the apparatus configuration can be simplified.

<Third Embodiment>
FIG. 8 is a diagram showing only the abnormal cooling mechanism 222 included in the battery device 210 according to the third embodiment of the present invention and its peripheral configuration.
In addition, in the same figure, the same code | symbol is attached | subjected about what was demonstrated in 1st or 2nd embodiment, and the description is abbreviate | omitted.
As shown in this figure, the abnormal cooling mechanism 222 of this embodiment is provided with a capillary tube 254 as a decompression device instead of the expansion valve 54 with respect to the abnormal cooling mechanism 122 of the second embodiment.
According to this embodiment, the same effects as those of the first and second embodiments can be obtained.

<Fourth embodiment>
FIG. 9 is a diagram showing only the abnormal cooling mechanism 322 included in the battery device 310 according to the fourth embodiment of the present invention and its peripheral configuration.
In addition, in the same figure, the same code | symbol is attached | subjected about what was demonstrated in 1st-3rd embodiment, and the description is abbreviate | omitted.
As shown in this figure, the battery device 310 of this embodiment has a plurality of sets of assembled batteries 18 formed by arranging a plurality of unit cells 24 side by side. In the abnormal cooling mechanism 322, the same heat exchangers 352A and 352B as in the first embodiment are provided for each assembled battery 18.
Thereby, according to the present embodiment, in addition to the effects described in the first embodiment, the output power of the battery device 310 is increased by increasing the number of the assembled batteries 18, and which unit cell 24 of which assembled battery 18 is used. Even if the combustion gas is generated from the refrigerant, the combustion gas and the refrigerant can be subjected to heat exchange, and the refrigerant gas can be quickly injected.

<Fifth Embodiment>
FIG. 10 is a perspective view showing a configuration of a battery device 410 according to the fifth embodiment of the present invention, FIG. 11 is a sectional view thereof, and FIG. 12 is a perspective view showing a main configuration inside thereof.
In these drawings, the same reference numerals are given to those described in the first to fourth embodiments, and the description thereof is omitted.
As shown in these drawings, the battery device 410 according to the present embodiment has two battery plates 16 each including a cooling plate 40 and a plurality of unit cells 24 arranged side by side on the cooling plate 40. The assembled battery 18 is arranged side by side.
In the abnormal cooling mechanism 422 of the present embodiment, the refrigerant tank 50 is disposed side by side with the assembled battery 18 on the cooling plate 40, and the heat exchange plate 453 is disposed above each assembled battery 18 above it. Then, each of the two refrigerant tubes 51 drawn out from the refrigerant tank 50 extends over each heat exchanging plate 453 and is folded back in a U-shape, whereby a heat exchanger 452 is configured, and an end portion of each refrigerant tube 51 An expansion valve 454 is attached as a pressure reducing device.
Thus, according to the present embodiment, in addition to the effects described in the first embodiment, the refrigerant tank 50 is disposed on the cooling plate 40 that cools the assembled battery 18. At the same time, the refrigerant tank 50 is also cooled. Thereby, for example, when the temperature in the battery case 16 reaches a high temperature in summer or the like, malfunction of the abnormal cooling mechanism 422 due to the high temperature can be prevented.

The above-described embodiments merely show one aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.
For example, in each of the above-described embodiments, the battery device mounted on the electric vehicle 1 has been described. However, the present invention is not limited to this, and a hybrid vehicle, a two-wheeled vehicle, a train, an airplane, etc. The battery device of the present invention can be used as a power source for any vehicle. Furthermore, the battery device of the present invention can be used not only as a vehicle but also as a power source for any device that requires a high voltage.

It is a figure which shows the structure of the four-wheeled electric vehicle carrying the battery apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of a battery apparatus. It is a figure which shows the structure of a unit cell. It is a figure which shows the pressure of the refrigerant | coolant which a pressure valve opens with the relationship between the temperature and pressure of a refrigerant | coolant. It is a figure which shows typically the cooling operation by an abnormal cooling mechanism. It is operation | movement explanatory drawing when the thermal runaway generate | occur | produced with the unit cell. It is a figure which shows the battery apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the battery apparatus which concerns on 3rd Embodiment of this invention. It is a figure which shows the battery apparatus which concerns on 4th Embodiment of this invention. It is a perspective view which shows the structure of the battery apparatus which concerns on 5th Embodiment of this invention. It is sectional drawing of the battery apparatus. It is a perspective view which shows the main structure inside the battery apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric vehicle 4 Vehicle drive motor 10, 110, 210, 310, 410 Battery device 16 Battery case 18 Assembly battery 22, 122, 222, 322, 422 Abnormal cooling mechanism 24 Unit cell 30 Safety valve 32 Exhaust safety valve 50, 150 Refrigerant tank 51 Refrigerant pipe 52, 352A, 352B Heat exchanger 54, 454 Expansion valve (pressure reduction device)
56 Pressure valve 254 Capillary tube (pressure reduction device)

Claims (3)

In a battery device in which a unit cell is stored in a battery case,
In the battery case, a refrigerant tank storing a nonflammable refrigerant, or a heat exchanger connected to the refrigerant tank is provided at a location exposed to the combustion gas generated from the unit cell, the refrigerant tank, or the A pressure reducing device and a pressure valve that opens at a predetermined refrigerant pressure are sequentially connected to the heat exchanger,
The battery device is characterized in that the pressure valve is opened as the refrigerant tank or the heat exchanger is heated by the combustion gas, and the refrigerant decompressed and expanded by the decompression device is injected into the battery case. . The battery device according to claim 1,
A safety valve for ejecting the combustion gas is provided in the case body of the unit cell,
In the battery case, a plurality of the unit cells are arranged with the safety valve arrangement side aligned in one direction, facing the safety valve of each unit cell, and the refrigerant tank or the heat exchanger. A battery device characterized in that the battery device is extended. The battery device according to claim 1 or 2,
The battery case has a sealed structure, and has an exhaust valve that opens when the internal pressure reaches a predetermined pressure and communicates the inside and the outside.

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