JP4824842B2 - Battery module - Google Patents

Description

  The present invention relates to a battery module, and more specifically to a technique for improving the safety of a battery module.

  For example, a large number of batteries (for example, secondary batteries) are used in a power source for driving an electric vehicle or a hybrid vehicle in a state where they are connected in series or in parallel, or a combination of parallel and series. A battery pack or a battery module is a battery pack or battery module in which one or a plurality of batteries are taken as one unit and a charge / discharge control circuit and a safety device are added to the unit. In an electric vehicle and a hybrid vehicle, a plurality of battery modules are usually used by being electrically connected to each other.

  High capacity batteries, particularly lithium ion batteries, used for such battery modules are usually provided with safety valves such as explosion-proof valves. When the battery is placed in an abnormally high temperature environment or overcharged, a large amount of gas is generated inside the battery. At this time, if the internal pressure of the battery rises abnormally, the safety valve is activated to release the gas to the outside.

  The battery in which the safety valve has been activated is interrupted in order to stop further use. Therefore, it is necessary to detect the operation of the safety valve. For this reason, for example, Patent Document 1 proposes arranging a temperature sensor for detecting the temperature of the jet gas in the vicinity of the safety valve. In Patent Document 2, it is proposed that a wire is attached to the safety valve so that the safety valve is disconnected at the same time as it is operated, and the operation of the safety valve is detected by detecting the cutting of the wire.

JP 11-25938 A JP 2005-322471 A

  However, when a temperature sensor is arranged in the vicinity of the safety valve, it is necessary to provide a temperature sensor for each of the plurality of batteries, which increases costs and increases the size of the battery module. In particular, in a driving power source such as an electric vehicle, the number of batteries may reach 100 or more. In such a case, the number of temperature sensors becomes large, and the cost increases significantly. Also, the wiring for connecting the temperature sensor to the control circuit or the like is very long. For this reason, false detection due to noise mixed in the wiring also increases.

  Furthermore, the method of using a temperature sensor for detecting the operation of the safety valve has a fundamental problem that it takes time for detection. Immediately after the operation of the safety valve, the temperature of the jet gas is low, so it takes time to detect the operation of the safety valve. As a result, it is conceivable that the current cannot be interrupted quickly when an abnormality occurs in the battery.

  Further, in the method of attaching a wire to the safety valve and detecting the operation of the safety valve, it is necessary to perform complicated processing on each battery in the battery manufacturing process, which increases the number of steps. As a result, it is also necessary to rearrange the battery production line. This further increases the cost. Also in this case, the increase in false detection by increasing the wiring length is the same as in the case of providing a temperature sensor.

  An object of this invention is to detect the operation | movement of the safety valve of the battery which comprises a battery module simply and with sufficient precision.

One aspect of the present invention is a plurality of batteries each having a safety valve that is electrically connected to each other and that discharges internal gas to the outside when the internal pressure becomes a predetermined value or more.
At least one facing member facing the safety valve of the plurality of batteries;
The present invention relates to a battery module that includes at least one sound sensor that is disposed between the opposing member and the plurality of batteries and detects an operation sound of the safety valve.

Cell module, based on the output signal of the sound sensor, the safety valve you provided a valve operating detector for detecting that it has operated. The sound sensor outputs a first signal corresponding to the detected sound volume. The valve operation detection unit determines that the safety valve has been operated when the first signal corresponds to a loudness greater than or equal to a reference value.

  Here, the plurality of batteries electrically connected to each other is also referred to as a battery assembly or a cell group. And it is preferable that the said opposing member which covers at least one part of a battery assembly functions as a sound insulation member. The sound sensor is disposed between the facing member and the battery assembly, that is, on the battery assembly side of the facing member. For example, the safety valve has a valve mechanism that includes an easily breakable portion that breaks when the internal pressure of the battery is equal to or higher than a predetermined value and discharges internal gas to the outside. A valve operation detection unit that detects that the safety valve (valve mechanism) is operated based on an output signal of the sound sensor can be provided in a predetermined control unit (ECU or the like).

  In the present invention, the operation of the safety valves of a plurality of batteries can be detected only by providing one or a small number of sound sensors for the plurality of batteries. Therefore, the operation of the safety valve can be detected with sufficient accuracy without causing the system to become complicated and large.

  The novel features of the invention are set forth in the appended claims, and the invention will be further described by reference to the following detailed description in conjunction with the other objects and features of the invention, both in terms of construction and content. It will be well understood.

It is a block diagram which shows schematic structure of the battery module which concerns on one Embodiment of this invention. It is a perspective view which shows the internal structure of a battery module. It is a perspective view which shows the external appearance of a restraint member. It is a perspective view of a part of cell group. It is a perspective view which shows the state which has arrange | positioned the opposing member in the cell group. It is a block diagram which shows schematic structure of the battery module which concerns on other embodiment of this invention. It is a block diagram which shows schematic structure of the battery module which concerns on further another embodiment of this invention.

The battery module of the present invention is electrically connected to each other, and has a plurality of batteries each having a safety valve that discharges internal gas to the outside when the internal pressure becomes a predetermined value or more, and faces the safety valves of those batteries with a space therebetween. And at least one facing member disposed, and a sound sensor disposed between the facing member and the battery and detecting an operation sound of the safety valve. Here, the battery module, based on the output signal of the sound sensor, a safety valve Ru is provided with a valve operating detector for detecting that it has operated. The sound sensor outputs a first signal corresponding to the detected sound volume. The valve operation detection unit determines that the safety valve has been operated when the first signal corresponds to the loudness of the reference value or more. However, the valve operation detection unit may not be installed integrally with the battery module as long as it can function in cooperation with the sound sensor, and is provided outside the battery module, such as a load device to which the battery module is mounted. You can also.

  The safety valve operates to eject gas inside the battery to the outside when the battery internal pressure rises abnormally. Therefore, a relatively loud sound is generated when the safety valve is activated. Therefore, the opposing member that faces the safety valve of each battery is arranged at a distance from the safety valve, and the sound sensor is arranged between the opposing member and the battery, so that the operation sound of the safety valve can be easily achieved by the sound sensor Can be detected. Therefore, only by providing at least one sound sensor in the battery module, it is possible to detect that the safety valve of at least one battery among the plurality of batteries has been operated based on the output signal of the sound sensor.

  Here, if the sound sensor is arranged at a position relatively close to the safety valves of all the batteries, and the opposing member is arranged on the outside thereof, even if the sensitivity of the sound sensor is lowered, the operation sound of the safety valve can be easily obtained. Can be detected. Furthermore, by lowering the sensitivity of the sound sensor, it is difficult to detect external sounds, and it is possible to prevent erroneous detection of the operation of the safety valve. Therefore, it is possible to detect the operation of the safety valve with sufficient accuracy by appropriately arranging the sound sensor and the facing member. At this time, the number of sound sensors is not limited to one, and two or more sound sensors can be used so that the distance between the safety valve of each battery and the sound sensor does not become too large.

  In addition, when the batteries are arranged so that the safety valves of a plurality of batteries do not release gas in the same direction but release gas in two or more directions, they face all the directions. When the members are arranged and the sound sensors are arranged between the facing members and the batteries, the operation of the safety valves of all the batteries can be detected with sufficient accuracy.

  In order to suppress an increase in the number of sound sensors, it is preferable to arrange each battery so that the direction in which the gas from the safety valve of the plurality of batteries is released is 2 or less. Thereby, an increase in cost can be suppressed and an increase in wiring length can also be suppressed. Therefore, it is possible to suppress the erroneous detection due to the mixing of noise and detect the operation of the safety valve with high accuracy.

  Here, the opposing member is preferably formed from a material having as high a sound insulating property as possible from the viewpoint of blocking external sound. Thereby, detection accuracy improves. Although it does not specifically limit, a counter member can be formed so that the sound transmission loss of the sound component of 500 Hz measured based on JIS-A1416 may be 20-40 dB.

  As described above, according to the present invention, the operation of the safety valve can be detected simply and with sufficient accuracy for all the batteries of the battery module by using only at least one sound sensor. Therefore, it is possible to detect the operation of the safety valves of all the batteries with simple and sufficient accuracy without causing the system to be complicated and large. Therefore, an increase in cost can be suppressed. Furthermore, when the safety valve is activated, the operation can be immediately detected with almost no interval. Therefore, when the safety valve is activated, necessary measures such as cutting off the battery current can be quickly performed.

  In an aspect in which the safety valve includes a thin battery part (easy breakable part) provided on a metal battery case that houses the power generation element of the battery or a metal sealing plate that seals the opening of the battery case, the safety valve Since the part is made of metal, generally, the operation sound of the safety valve becomes relatively loud. Therefore, in such a case, the operation of the safety valve can be detected with higher accuracy.

  In one form of this invention, a sound sensor outputs the 1st signal according to the detected sound volume, and a valve action detection part is when the 1st signal respond | corresponds to the sound volume more than a reference value. It is determined that the safety valve has been activated.

  By detecting the operation of the safety valve by such a method, it is possible to prevent the mechanism from becoming complicated. As a method for detecting the operation of the safety valve other than the above, for example, it is conceivable to frequency-analyze the operation sound of the safety valve in advance and store the result. The frequency of the sound detected by the sound sensor during use of the battery module is analyzed, and if the result matches the stored result, it can be determined that the safety valve has been activated. Such a detection method requires a circuit for frequency analysis of the sound detected by the sound sensor.

  On the other hand, in this embodiment in which the operation of the safety valve is detected by comparing the loudness (for example, sound pressure level) detected by the sound sensor with a reference value, an arithmetic processing unit or the like having a high processing capacity is provided as a valve. Without using the operation detector, the operation of the safety valve can be detected with sufficient accuracy. Therefore, an increase in cost can be suppressed. In addition, since processing does not take time, it can be immediately detected that the safety valve has been activated.

  In another embodiment of the present invention, the frequency of at least one operating sound of the safety valves of the plurality of batteries of the battery module is different from the frequency of the operating sounds of the other safety valves. The sound sensor outputs a second signal corresponding to the detected frequency of the operating sound together with the first signal. And a valve action detection part distinguishes which safety valve of a plurality of batteries acted based on the 1st signal and the 2nd signal.

  For example, if the frequency of the operation sound of the safety valve of a plurality of batteries is set to two types, the plurality of batteries can be divided into two groups. Then, by analyzing the frequency of the operating sound detected by the sound sensor, it is possible to know which group of battery safety valves has been operated. Therefore, it becomes easy to specify the battery in which the safety valve is activated. Furthermore, for example, if the frequency of the operation sound of the safety valve of all the batteries included in the battery module is different from each other, the frequency of the operation sound detected by the sound sensor is analyzed to accurately determine which battery safety valve has been operated. I can know. The first signal can be used to determine whether or not there is a battery with a safety valve activated.

  As a result, it is possible to cut off only the current of the battery in which the safety valve is activated. Furthermore, the work for exchanging the battery later can be performed efficiently. In particular, when the structure of the battery module is such that it is difficult to visually recognize the safety valve of each battery from the outside, the effect becomes remarkable.

  In still another embodiment of the present invention, the sound sensors are arranged such that the distances from the safety valves of the plurality of batteries are all different. And a valve action detection part discriminate | determines the battery which the safety valve act | operated based on the said 1st signal.

  As described above, if the sound detected by the sound sensor is larger than the reference value, it can be understood that the safety valve of at least one battery in the battery module has been activated. Furthermore, when the magnitude of the operating sound of the safety valve is always constant, the distance between the sound sensor and the safety valve can be known based on the magnitude of the operating sound detected by the sound sensor. Therefore, the battery in which the safety valve is activated can be determined among the plurality of batteries of the battery module, and the same effect as described above can be achieved.

  In still another embodiment of the present invention, the sound sensor has a first sensor and a second sensor arranged at a predetermined distance. And a valve action detection part discriminate | determines the battery which the safety valve act | operated based on the 1st signal which a 1st sensor and a 2nd sensor output, respectively.

  For example, when a plurality of batteries of the battery module are arranged so that the safety valves of the batteries are arranged in a line, the first sensor and the second sensor are arranged at different positions in the arrangement direction. Thereby, the ratio of the volume of the operation sound detected by the first sensor and the second sensor is determined according to the position of the battery where the safety valve is operated. Therefore, even when the operating sound of the safety valve is not always constant, it is possible to accurately specify the battery in which the safety valve is operated by comparing the operating sounds detected by the sensors. Therefore, the same effect as that described above can be achieved.

  In another embodiment of the present invention, the plurality of batteries are divided into two or more groups, and at least one sound sensor is disposed corresponding to each of the two or more groups. The valve operation detection unit detects the operation of the safety valve in groups.

  As described above, in a mode in which the safety valves of a plurality of batteries discharge gas in two or more directions, it is necessary to provide a plurality of sound sensors. In such a case, the valve operation detection unit is configured to detect the operation of the safety valve in units of groups. Thereby, for example, when each group is connected in parallel, it is possible to perform control such that only the battery current of the group in which the operation of the safety valve is detected is cut off. Therefore, it is possible to supply power to the load device from the battery of the group in which the operation of the safety valve is not detected. For example, if the load device is an electric vehicle, the operation can be continued to a predetermined facility. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of a battery module according to an embodiment of the present invention.
The battery module 10 includes a cell group 14 including a predetermined number (10 in the illustrated example) of batteries 12 and an ECU (Electronic Control Unit) 16. The safety valve 42 of each battery 12 faces the plate-like counter member 18. The facing member 18 is preferably formed from a material with high sound insulation.

  In order to detect the operation sound of the safety valve 42 of each battery 12, a predetermined number (one in the illustrated example) of the sound sensors 20 is disposed between the facing member 18 and each battery 12. The sound sensor 20 may be provided so as to be in contact with the facing member 18 or may be provided so as not to be in contact.

  As the sound sensor 20, an electrostatic (condenser) microphone, an electrodynamic microphone, or the like can be used. The ECU 16 is a microprocessor or a memory such as a CPU (Central Processing Unit), a RAM (Random Access Memory) and a ROM (Read Only Memory), an input / output device and a communication. Includes modules. The ECU 16 performs control such as calculation of the battery capacity, determination of the required charge / discharge amount, and control of charge / discharge. The ECU 16 includes a valve operation detection unit 17 described later. The output signal of the sound sensor 20 is input to the valve operation detection unit 17.

  FIG. 2 is a perspective view showing the external appearance of the battery module with the ECU and the opposing member 18 removed. FIG. 3 is a perspective view showing an appearance of a restraining member that restrains the batteries 12 in a stacked state. The battery 12 has a flat rectangular shape, and constitutes a cell group 14 by being stacked in the thickness direction thereof. A pair of end plates 22 are respectively arranged outside the cell group 14 in the stacking direction.

  Each of the pair of end plates 22 has a substantially rectangular shape, and the four corners are connected to each other by four rod-shaped restraining members 24. Further, the end plates 22 are connected to each other by rod-like connecting members 26 at the center positions of the two long sides.

  For the material of the restraining member 24, it is preferable to use a lightweight and high-strength engineering plastic such as GF-PET (glass fiber reinforced polyethylene terephthalate) or PC (polycarbonate). For the connecting member 26, for example, anodized aluminum can be used.

  As shown in FIG. 3, the restraining member 24 is provided with a predetermined number (10 in the illustrated example) of cell engaging portions 24a so as to be aligned in the axial direction. Each battery 12 is supported by the four restraining members 24 between the pair of end plates 22 by engaging the cell engaging portions 24a and the four corners of the four restraining members 24, respectively.

  FIG. 4 is a perspective view showing a part of the cell group. FIG. 4 focuses on two adjacent batteries 12 in the cell group 14.

  In the cell group 14, a gap for introducing a cooling fluid is provided between two adjacent batteries 12. In the gap, a substantially rectangular spacer 30 having a waved portion 32 is disposed in order to suppress expansion of the battery 12 and secure a fluid flow path. A plurality of straight grooves parallel to the short sides of the spacers 30 are provided on both surfaces of the wavy portion 32 at a constant pitch in a direction parallel to the long sides of the spacers 30. Between each surface of the spacer 30, the phase of the plurality of grooves is shifted by ½ pitch. As a material of the spacer 30, for example, GF-PET or PC can be used.

  Although not shown, the battery 12 is a secondary battery in which a positive electrode, a negative electrode, a separator interposed therebetween, and a power generation element composed of an electrolyte are housed in a metal battery case 34. Such secondary batteries include nickel metal hydride batteries and lithium ion batteries. In the case of a nickel metal hydride battery, nickel oxyhydroxide is used for the positive electrode, a hydrogen storage alloy is used for the negative electrode, and an aqueous potassium hydroxide solution is used for the electrolyte. In the case of a lithium ion battery, lithium cobalt oxide is used for the positive electrode and a carbon material such as graphite is used for the negative electrode.

  More specifically, the battery 12 includes a bottomed rectangular battery case 34 having an opening at one end, and a sealing plate 36 that seals the opening. The sealing plate 36 is entirely made of metal (for example, aluminum), and a negative electrode external terminal 38 and a liquid injection port 40 connected to the negative electrode project from the surface of the sealing plate 36. The battery case 34 is connected to the positive electrode, and the battery case 34 and the sealing plate 36 function as a positive electrode external terminal.

  Further, the sealing plate 36 is provided with a safety valve 42 including a thin portion. The thin portion can be provided by forming a notch-like groove in the sealing plate 36. In such a safety valve 42, when the battery internal pressure rises abnormally, the thin portion is relatively easily broken and releases the gas inside the battery case 34 to the outside. A sound is generated when the thin-walled portion made of metal breaks. Thus, in the battery 12 of the illustrated example, since the safety valve 42 includes a metal part, the operation noise is increased, and the detection accuracy of the operation of the safety valve 42 is improved.

  The capacity of the battery 12 can be 3 to 100 Ah. If the capacity | capacitance of the battery 12 is such a range, since the operating sound of the safety valve 42 becomes considerably loud, it is suitable for applying the present invention. A more preferable range of the capacity of the battery 12 is 5 to 30 Ah. The present invention can be suitably applied to such a large secondary battery.

  As shown in FIG. 4, in the cell group 14 in the illustrated example, the two adjacent batteries 12 are arranged so that the sealing plates 36 provided with the safety valves 42 are in the same direction. As a result, in the entire cell group 14, the safety valves 42 of the batteries 12 are arranged in a line so as to release gas in the same direction.

  Furthermore, the negative external terminal 38 of one of the two adjacent batteries 12 (battery 12 in FIG. 4) is connected to the positive external terminal (sealing plate 36) of the other battery 12 and a conductor. They are connected by a plate 44. Further, the negative electrode external terminal 38 of the other battery 12 is further connected to the positive electrode external terminal (sealing plate 36) of the adjacent battery 12 by a connection plate 44 (not shown). In this way, all the batteries 12 in the cell group 14 are connected in series.

  As described above, by disposing the sealing plates 36 of all the batteries 12 in the same direction, the safety valves 42 of all the batteries 12 release the gas in the same direction. For this reason, it becomes possible to detect the operation sound of the safety valve 42 of all the batteries with one sound sensor.

  It is possible to stack the batteries 12 so that the sealing plates 36 of the adjacent batteries 12 face each other. In this case, the opposing members 18 are arranged in the respective directions, and at least one sound sensor is arranged between each opposing member and the cell group 14, so that the operating sounds of the safety valves 42 of all the batteries 12 are operated. Can be detected.

  At this time, it can be considered that the batteries 12 are divided into two groups in which the direction of the sealing plate 36 is different. In such a case, the valve operation detection unit 17 can detect the operation of the safety valve 42 for each group.

  In the cell group 14, the battery 12 at one end in the stacking direction of the batteries 12 has the negative external terminal 38 connected to another battery module 10 or a load device (not shown), and the battery 12 at the other end is connected to the positive external terminal (sealing). The plate 36 or the like) is connected to another battery module 10 or a load device (not shown).

  FIG. 5 is a perspective view showing a state in which one end portion of the cell group is covered with a cover plate corresponding to the facing member in FIG. The cover plate 46 covers an end portion where the sealing plates 36 of the batteries 12 are arranged in the cell group 14. The end opposite to the end is covered with another cover plate 48. The cover plate 46 corresponds to the facing member 18 in FIG. Therefore, the cover plate 46 is preferably formed from a material having a high sound insulating property. The sound sensor 20 can be attached to the center of the inner surface of the lid plate 46, for example.

Next, the operation detection of the safety valve will be described.
The valve operation detector 17 of the ECU 16 detects that the safety valve 42 of at least one battery 12 of the cell group 14 has been operated based on the output signal of the sound sensor 20. For example, a sensor (such as the above-described condenser microphone) that outputs a signal corresponding to the detected sound level is used as the sound sensor 20. Then, the valve operation detection unit 17 obtains the volume (sound pressure level) Lp of the sound detected by the sound sensor 20 from the output signal of the sound sensor 20. Then, the loudness Lp is compared with the reference value LpR.

  At this time, when the volume Lp detected by the sound sensor 20 has reached the reference value LpR (Lp ≧ LpR), the valve operation detection unit 17 operates the safety valve 42 of at least one battery 12 of the cell group 14. Judge that it was done. In this way, the valve operation detection unit 17 can detect that the safety valve 42 of at least one battery 12 belonging to the cell group 14 has been operated based on the output signal of the sound sensor 20. Here, the reference value LpR can be stored in a memory (for example, ROM) of the ECU 16.

  The cover plate 46 (opposing member 18) can be formed from a member whose acoustic transmission loss of a 500 Hz sound component is 20 to 40 dB when measured based on JIS-A1416, for example.

  As such a material, a glass fiber or a resin containing an inorganic filler can be considered. Moreover, such a resin has insulation and heat resistance, and can be provided with high sound insulation. It is preferable that the material of the end plate 22 and the restraining member 24 is also made of a highly sound-insulating material such as a glass fiber or a resin containing an inorganic filler in order to suppress noise from the outside. In addition, desired sound insulation performance can be obtained by adjusting the thickness and density of the cover plate 46.

  Although it depends on the capacity of the battery 12, the reference value LpR may be set to a volume of 70 to 100 dB. More preferably, the detection accuracy of the operation of the safety valve 42 can be improved by setting the reference value LpR to a volume of 80 to 90 dB.

  When the valve operation detection unit 17 detects that the safety valve 42 of at least one battery 12 of the cell group 14 has been operated, the ECU 16 controls the current of all the batteries 12 in the cell group 14 to be cut off. This is because each battery 12 is connected in series in the battery module 10 of FIGS. In addition, if the battery module 10 is, for example, an in-vehicle battery module, a process for warning the driver to that effect (a warning lamp lighting process or the like) may be performed.

  With the above configuration, it is possible to detect that the safety valve 42 of at least one battery 12 included in the battery module 10 has been operated simply by providing at least one sound sensor 20 in the battery module 10. As a result, an increase in cost can be suppressed, and erroneous detection due to a long wiring can be prevented.

  The sound sensor 20 outputs a signal corresponding to the magnitude and frequency component of the detected sound, and the valve operation detection unit 17 detects the magnitude of the sound detected by the sound sensor 20 and the sound detected by the sound sensor 20. The operation of the safety valve 42 may be detected based on the frequency component. Alternatively, the operation of the safety valve 42 may be detected based only on the frequency component of the sound detected by the sound sensor 20.

  More specifically, the frequency of the sound when the safety valve 42 of each battery 12 is operated in the battery module 10 is analyzed in advance by a fast Fourier transform method, an autoregressive maximum entropy method, or the like. Then, the analysis result is stored in the memory of the ECU 16.

  When detecting the operation of the safety valve 42, whether or not the volume of the sound detected by the sound sensor 20 is equal to or higher than the reference value LpR, and whether or not the frequency component of the detected sound is applied to the frequency analysis reference value more than a predetermined level. Determine whether. Then, when the detected sound volume is equal to or larger than the reference value LpR and the detected sound frequency component is applied to the frequency analysis reference value for a predetermined degree or more, it is detected that the safety valve 42 is activated. With the above configuration, erroneous detection of the operation of the safety valve 42 can be suppressed. Alternatively, the operation of the safety valve 42 can be detected simply from the result of frequency analysis of the sound detected by the sound sensor 20.

  In the present embodiment, the battery 12 has a flat rectangular shape, but the battery 12 may have another cylindrical shape, a prismatic shape, or the like. Even in that case, the sealing plates 36 provided with the safety valves 42 of the plurality of batteries 12 are arranged in the same direction, and as a result, the safety valves 42 of the batteries 12 in the same direction in the cell group 14 as a whole. Can be arranged so as to release them.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described. The second embodiment is a modification of the first embodiment, and the configuration of the battery module is basically the same as that shown in FIGS. Therefore, FIG. 1 to FIG.

  The second embodiment is different from the first embodiment in that the safety valve 42 of each battery 12 of the cell group 14 generates an operating sound having a different frequency. Then, the frequency component of the operating sound of the safety valve 42 of each battery 12 of the cell group 14 is stored in the memory of the ECU 16. When the sound detected by the sound sensor 20 is the reference value LpR, the valve operation detection unit 17 performs frequency analysis of the sound and compares the analysis result with the stored frequency component.

  If the analysis result matches any of the stored frequency components, it is determined that the safety valve 42 of the matched battery has been activated. On the other hand, if the analysis result does not match any of the stored frequency components, the sound is considered to be an external sound, and therefore it is determined that there is no battery 12 in which the safety valve 42 is activated. Accordingly, it is possible to determine which detection sound is the operation sound of the safety valve 42 of any battery 12 in the cell group 14 while preventing erroneous detection of the operation of the safety valve 42 of each battery 12.

  As a result, for example, when each battery 12 is connected in parallel, only the current of the battery 12 can be cut off. Furthermore, when the battery 12 whose safety valve 42 is activated later is replaced, since the battery 12 is specified, the work can be performed efficiently. In particular, when the battery module has a structure in which it is difficult to visually recognize the safety valve 42 of each battery 12 from the outside, the effect becomes remarkable.

(Embodiment 3)
Next, Embodiment 3 of the present invention will be described with reference to FIG. The third embodiment is a modification of the first embodiment. As shown in FIGS. 1 and 5, in the battery module 10 of the first embodiment, the sound sensor 20 is arranged at the center of the cell group 14 in the direction in which the batteries 12 are arranged. Thus, the sound sensor 20 and the safety valve 42 of the battery 12 at the end of the cell group 14 are prevented from being separated too much.

  On the other hand, in the battery module 10 </ b> A of FIG. 6, the sound sensor 20 is arranged at one end of the cell group 14 in the direction in which the batteries 12 are arranged. As described above, by disposing the sound sensor 20 at a position where the arrangement direction of the batteries 12 is deviated, the distances between the sound sensor 20 and the safety valve 42 of each battery 12 are all different. Therefore, the magnitude of the operating sound of the safety valve 42 detected by the sound sensor 20 differs for each battery 12. For this reason, it is possible to know the position of the battery 12 where the safety valve 42 is operated based on the magnitude of the operating sound detected by the sound sensor 20. Therefore, the battery 12 in which the safety valve 42 is activated can be specified.

  More specifically, in the battery module 10A, the safety valve 42 of each battery 12 of the cell group 14 is operated, and the loudness detected by the sound sensor 20 at that time is measured in advance for all the batteries 12. . And the result is memorize | stored in the memory of ECU16, When the operation sound of the safety valve 42 is actually detected by the sound sensor 20, the magnitude | size of the detected sound and the data memorize | stored in memory are collated. This makes it possible to determine which battery 12 has operated the safety valve 42. Therefore, the same effect as that of the second embodiment can be achieved. At this time, the reference value LpR can be made equal to a value obtained by measuring the operating sound of the safety valve 42 farthest from the sound sensor 20 in advance and storing it in the memory of the ECU 16.

(Embodiment 4)
Next, Embodiment 4 of the present invention will be described with reference to FIG. The fourth embodiment is a modification of the first embodiment. As shown in FIGS. 1 and 5, in the battery module 10 according to the first embodiment, only one sound sensor 20 is arranged in the center of the cell group 14 in the direction in which the batteries 12 are arranged.

  On the other hand, in the battery module 10 </ b> B of FIG. 7, a pair of sound sensors 20 </ b> A and 20 </ b> B are arranged one at each end of the cell group 14 in the direction in which the batteries 12 are arranged. In this way, by arranging the plurality of sound sensors 20A and 20B at a predetermined distance, the ratio of the detected sound levels of the sound sensors 20A and 20B according to the position of the battery 12 where the safety valve 42 is operated. Is decided. Therefore, it becomes possible to specify the battery 12 in which the safety valve 42 is operated more accurately.

  More specifically, in the battery module 10B, the safety valve 42 of each battery 12 of the cell group 14 is operated, and the ratio of the sound levels detected by the sound sensors 20A and 20B at that time is set for all the batteries 12. Calculate in advance. The result is stored in the memory of the ECU 16.

  When the operation sound of the safety valve 42 is actually detected by the sound sensors 20A and 20B, each detection sound is compared with the reference value LpR. As a result, if the detected sounds of both the sound sensors 20A and 20B are equal to or higher than the reference value LpR, it is determined that the safety valve 42 of at least one battery 12 in the cell group 14 has been activated. Then, the ratio of the detected sound magnitudes of the sound sensors 20A and 20B is calculated, and the calculated ratio is collated with the data stored in the memory. This makes it possible to determine which battery 12 has operated the safety valve 42. Further, when the calculated ratio and the data stored in the memory do not match at all, the sound is considered to be an external sound, so it can be determined that there is no battery 12 in which the safety valve 42 is activated. Therefore, the same effect as that of the second embodiment can be achieved.

  As described above, in the fourth embodiment, the battery 12 in which the safety valve 42 is activated is specified based on the ratio of the detected sounds of the plurality of sound sensors 20A and 20B. Even if it is not constant, the battery 12 in which the safety valve 42 is activated can be specified. Therefore, it is possible to accurately determine the battery 12 in which the safety valve 42 is operated.

  The battery module of the present invention can easily detect the operation of the safety valve of the battery included therein. As a result, maintenance and the like are facilitated, and therefore, it is suitably used as a large-capacity and high-output application such as an electric vehicle or a hybrid vehicle power source.

  While this invention has been described in terms of the presently preferred embodiments, such disclosure should not be construed as limiting. Various changes and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains after reading the above disclosure. Accordingly, the appended claims should be construed to include all variations and modifications without departing from the true spirit and scope of this invention.

10 ... Battery module,
12 ... Battery,
14 ... cell group,
16 ... ECU,
17 ... Valve operation detection unit,
18. Opposing member,
20, 20A, 20B ... sound sensor,
42 ... Safety valve,
46 ... lid plate,

Claims (5)

A plurality of batteries that are electrically connected to each other and each have a safety valve that discharges internal gas to the outside when the internal pressure becomes a predetermined value or more,
At least one facing member facing the safety valve of the plurality of batteries;
At least one sound sensor disposed between the opposing member and the plurality of batteries and detecting an operation sound of the safety valve;
Based on an output signal of the sound sensor, comprising a valve operation detection unit that detects that the safety valve has been operated ,
The sound sensor outputs a first signal corresponding to the detected sound volume,
The valve operation detection unit is a battery module that determines that the safety valve has been activated when the first signal corresponds to a loudness greater than or equal to a reference value . The frequency of at least one operating sound of the safety valve of the plurality of batteries is different from the frequency of operating sounds of the other safety valves;
The sound sensor further outputs a second signal corresponding to the detected sound frequency,
The valve actuation detection unit, based on the first and second signals, to determine the cell in which the safety valve is actuated, the battery module according to claim 1, wherein. The sound sensors are arranged such that the distances from the safety valves of the plurality of batteries are all different from each other,
The valve actuation detection unit, based on the first signal, to determine the cell in which the safety valve is actuated, the battery module according to claim 1. The sound sensor has a first sensor and a second sensor arranged at a predetermined distance;
The valve actuation detection unit, wherein the first sensor and second sensor outputs respectively based on the first signal, to determine the cell in which the safety valve is actuated, the battery module according to claim 1. The plurality of batteries are divided into two or more groups,
Corresponding to each of the two or more groups, at least one of the sound sensors is disposed,
The battery module according to any one of claims 1 to 4 , wherein the valve operation detection unit detects the operation of the safety valve in the group unit.

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