JP5098197B2 - Storage element module - Google Patents

Description

  The present invention relates to a power storage element module that can detect an operating state of a safety valve that operates to suppress bursting of a housing with a rise in pressure inside a battery with a simple structure and with high reliability.

  In recent years, high-performance secondary batteries have been actively developed as clean energy sources used in notebook computers, small portable devices, automobiles, and the like. The secondary battery used here is required to have a large capacity and a high output while being small and light, that is, a high energy density and a high output density. As secondary batteries that can achieve high energy density and high output density, non-aqueous electrolyte secondary batteries such as lithium ion batteries are considered promising. These secondary batteries configure a battery module by connecting a plurality of single cells in series and in parallel according to required output and electric power.

  In a non-aqueous electrolyte secondary battery such as a lithium ion battery, a decomposition gas of the electrolyte is generated when an abnormality such as overcharge or internal short circuit occurs. When cracked gas is generated, the internal pressure of the battery increases. In order to prevent the battery from bursting due to an increase in the internal pressure of the battery, a safety valve is provided to release the internal pressure of the battery when the pressure exceeds a certain level. When the internal pressure rises due to an abnormality, the safety valve operates to release the battery internal pressure. At that time, the flammable electrolyte solution and the electrolyte decomposition gas scattered inside the battery are scattered. Since there is concern about fire, explosion, and human body effects caused by flammable electrolyte and electrolyte decomposition gas scattered from the safety valve of the battery, it is necessary to detect the operating status of the safety valve and stop charging / discharging of the battery early. there were.

  With respect to such a problem, Patent Document 1 discloses means for directly detecting the operation of a safety valve in a battery module configured by connecting a plurality of single cells in series and in parallel.

  Patent Document 1 discloses a detection device that detects an operating state of a safety valve by detecting a conduction state of a conducting wire that is integrally provided at a portion where the safety valve is broken and is disconnected when the safety valve is broken.

  Further, Patent Documents 2 to 3 disclose means for indirectly detecting the operation of the safety valve.

  Patent Document 2 discloses a battery pack that uses a battery sensor that detects a battery temperature in combination with a sensor that detects a gas temperature discharged from a safety valve to reliably cut off current in an abnormal use state with a simple structure. Has been.

  In Patent Document 3, the detection electrode is composed of two or more conductive members disposed with a slight gap between each other, and the detection electrode disposed in the vicinity of the safety valve and the contents ejected through the safety valve. A power storage element that detects a short circuit is disclosed.

  However, in the detection device disclosed in Patent Document 1, the operating state of the safety valve is detected by detecting the conduction state of a conductor integrally provided in a portion where the safety valve is broken. There is a problem in that a conductor must be arranged on the safety valve of this type, and the structure of wiring and the like becomes complicated as the number of single cells increases.

  Moreover, in the battery pack disclosed in Patent Document 2, the temperature sensor installed on the safety valve detects the temperature of the gas scattered with the operation of the safety valve, thereby detecting the operating state of the safety valve. However, there is a problem that the temperature of the gas scattered from the safety valve at the initial stage of opening the valve is difficult to distinguish from the battery temperature during normal use, and the reliability of the detection of the safety valve operating state is lacking.

Furthermore, in the electric storage element disclosed in Patent Document 3, the operating state of the safety valve is detected by a short circuit of the contents scattered with the operation of the safety valve on the electrode composed of two or more conductive members. There is a concern about malfunction due to a short circuit caused by condensation between the electrodes. Further, as a means for detecting a short circuit, it is exemplified that a resistance element to which a voltage is applied is connected in parallel between electrodes for detecting a short circuit, and the terminal voltage of the low resistance element is monitored. Since a potential difference is applied between the conductive members, there is a concern about malfunction due to a short circuit due to migration. As described above, the power storage element disclosed in Patent Document 3 also has a problem that the detection reliability of the safety valve operating state is lacking.
JP 2005-322471 A JP 11-25938 A JP 2005-197279 A

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a highly safe power storage element module by detecting the operating state of a pressure release mechanism such as a safety valve with a simple structure with high reliability. To do.

  In order to solve the above-mentioned problems, the present inventors have made studies, and as a result, have come to make the present invention.

An electricity storage device module according to the present invention is an electricity storage device container provided with a pressure release mechanism that seals an electrode body together with an electrolyte and opens when the internal pressure becomes a predetermined pressure or higher to reduce the internal pressure. In a power storage device module in which a plurality of power storage devices having electrical characteristics are electrically connected, a position where the electrolyte discharged from the pressure release mechanism can come into contact when the pressure in the power storage device container exceeds a predetermined pressure And having a substantially linear linear member made of a conductive polymer and in contact with the electrolytic solution, and having a detection device for detecting a change in electrical resistance due to disconnection due to contact of the linear member with the electrolytic solution. And

  By adopting this configuration, it is possible to detect discharges such as electrolyte that scatters with the operation of the pressure release mechanism of the storage element that constitutes the storage element module, and to detect the operating status of the pressure release mechanism with a simple structure and reliability It became possible to do.

Storage element module according to the present invention, the electric element has a substantially linear linear member electrolyte made of conductive polymer is in contact, the electrical resistance due to breakage by contact with the electrolyte of the linear member It is characterized by detecting changes. When the electric element is made of a linear member made of a conductive polymer, the linear member dissolves or dissolves when it comes into contact with the discharged matter, and breaks, and the electric resistance of the electric element greatly changes (increases). ). Since the resistance changes greatly, a change in electrical characteristics can be easily detected. Since the electric element is made of a linear member made of a conductive polymer, a change in electric resistance can be detected particularly when the discharged substance is made of an electrolytic solution.

The electric storage element module according to claim 2 of the present invention is characterized in that, in addition to the configuration according to claim 1 , the conductive polymer is polythiophene that is soluble in the electrolytic solution . In particular, polythiophene dissolves in the electrolyte of a non-aqueous electrolyte battery, so when the effluent is an electrolyte of a non-aqueous electrolyte battery, it dissolves when the effluent comes into contact and the linear member is disconnected, resulting in electrical Changes in characteristics can be easily detected.

Storage element module according to the present invention, the electric element is preferably a detector of the gas sensor. With such a configuration, when the detection unit of the gas sensor comes into contact with the discharged matter, usually, the electrical resistance of the detection unit greatly changes (decreases). Since the resistance changes greatly, a change in electrical characteristics can be easily detected. Since the electric element is composed of the detection part of the gas sensor, it is possible to detect a change in electric resistance particularly when the discharged substance is made of a gaseous substance obtained by decomposing the electrolytic solution.

In the electricity storage device module of the present invention , the gas sensor is preferably a semiconductor gas sensor that detects reducing gas . Since the gas sensor is a semiconductor gas sensor, it is possible to detect reducing gases such as H2 and CH4 that are generated when the electrolyte of the nonaqueous electrolyte battery is decomposed. It becomes possible to detect a change in electrical resistance.

In the electricity storage device module of the present invention, the detection part of the gas sensor is preferably made of at least one selected from SnO ₂ and ZnO . By configuring the detection unit from these materials, it becomes possible to detect a change in electrical resistance when the discharged substance is made of a decomposition gas of the electrolytic solution.

In the electric storage element module of the present invention, it is preferable that the electric element is in contact with the discharge from the plurality of pressure release mechanisms . That is, the operation of a plurality of pressure release mechanisms can be detected with one electric element, and the operation of the pressure release mechanism of the power storage element module can be detected. The electrical element is placed in contact with the discharge from the multiple pressure release mechanisms in the container that collects the discharge from the pressure release mechanism or in the duct that discharges the discharge from the pressure release mechanism. It can be set as the structure to do.

In the electricity storage device module of the present invention, the electricity storage device is preferably a lithium ion secondary battery . The type of the electricity storage device constituting the electricity storage device module of the present invention is not limited as long as the electrode body is housed in the electricity storage device container together with the electrolyte, and the lithium battery, lithium ion secondary battery, electric A non-aqueous electrolyte secondary battery such as a double layer capacitor, a polymer battery, or a radical battery can be used. And it is especially preferable that the electrical storage element module of this invention is a lithium ion secondary battery of the secondary battery which can achieve a high energy density and a high output density.

  Hereinafter, the details of the electricity storage device module of the present invention will be described using examples. The lithium ion secondary battery module will be described as an example of the power storage element module of the present invention, but the power storage element module of the present invention is not limited to this lithium ion secondary battery module.

Example 1
First, the lithium secondary battery 1 was manufactured by a conventionally known manufacturing method. First, the sheet-like positive electrode plate 11 and the negative electrode plate 12 were manufactured, and wound in a spiral shape in the longitudinal direction in a state of being laminated via a separator. This wound body was compressed in the radial direction by a method such as press molding to produce a flat wound electrode body 10. And this winding type electrode body 10 is joined to the electrode terminals 6 and 6 integrally joined to the cover body 140 which comprises a part of metal battery case 14, and the remaining part of the battery case 14 with electrolyte solution The abutting portion was hermetically and liquid-tightly joined by a method such as laser welding. Thus, the lithium secondary battery 1 in which the electrode body 10 and the electrolytic solution were enclosed in the battery container 14 was manufactured. In addition, the lithium secondary battery 1 has a rectangular parallelepiped outer peripheral shape, and a positive electrode terminal 60 and a negative electrode terminal 61 protrude from the upper surface of the battery container 14. Further, on the upper surface of the battery case 14 of the lithium secondary battery 1 and between the pair of electrode terminals 60 and 61, there is a safety valve 2 that is cleaved when the pressure inside the battery case 14 rises above a predetermined pressure. It is already made.

  Then, in a state where the five lithium ion secondary batteries 1 are electrically connected in series, they are arranged in the width direction, aluminum restraint plates 3 and 3 are arranged at both ends in the width direction, and two restraint plates 3 and 3 were restrained by an iron restraining band 4 to integrate five batteries. The safety valves 2 of the five lithium ion secondary batteries 1 are arranged on a straight line extending in the width direction.

  Then, both ends of a belt-like fixing base made of an insulating resin (polypropylene in this embodiment) are fixed to the pair of restraining plates 3 and 3. The fixed base 50 is disposed on each safety valve 2 of the five lithium ion secondary batteries 1 so as to face the safety valve 2 at a small interval, and the surface of the fixed base 50 facing the safety valve 2 is electrically conductive. A linear sensing element 90 made of a molecule (polythiophene in this embodiment) was arranged.

The detecting element 90 was connected to the resistance change detecting means 7. The resistance change detecting means 7 connects the detecting element 90 (R ₂ ) and the fixed resistor (R ₁ ) in series to construct a series circuit, applies a constant voltage between the series circuits, and sets the fixed resistor (R ₁ ). This is a means for monitoring fluctuations in the flowing voltage. In addition, the resistance change detection means 7 of a present Example is an example of a means to detect the resistance change of the detection element 90, and is not limited only to this form.

  In this way, the lithium secondary battery module 8 of this example could be manufactured. The lithium secondary battery module 8 of the present example is shown in FIGS. 1 shows the configuration of the lithium secondary battery 1, FIGS. 2 and 3 show the lithium secondary battery module 8 of this embodiment, and FIG. 4 shows a circuit of the resistance change detecting means 7.

(Operation)
The operation of the lithium secondary battery module 8 of this embodiment will be described below.

  The lithium secondary battery module 8 of the present embodiment is a battery module in which five lithium secondary batteries 1 are connected in series, and can be charged and discharged in the same manner as a normal battery module.

  Then, in one of the lithium secondary batteries 1 constituting the lithium secondary battery module 8 of the present embodiment, an abnormality such as overcharge or internal short circuit occurs, and a decomposition gas of the electrolyte is generated in the battery container. When the decomposition gas of the electrolytic solution is generated, the pressure inside the battery container increases, and the safety valve 2 is opened when the pressure exceeds a predetermined pressure.

  When the safety valve 2 is cleaved, a decomposition gas of the electrolytic solution is ejected from the safety valve 2 together with the electrolytic solution. The electrolytic solution ejected from the safety valve 2 is sprayed to and abuts (attaches) to the fixed base 50 and the detection element 90 arranged at positions facing each other with a small interval. The electrolytic solution adhering to the sensing element 90 dissolves polythiophene constituting the sensing element 90 in the adhering portion. The detection element 90 is formed in a linear shape and is disconnected by melting.

When the linear detection element 90 is disconnected, the voltage flowing through the fixed resistance (R ₁ ) in the resistance change detecting means 7 is greatly reduced, and the resistance change detecting means 7 detects this voltage drop.

In the lithium secondary battery module 8 of the present embodiment, when the resistance change detecting means 7 detects a decrease in the voltage flowing through the fixed resistor (R ₁ ), the electrolytic solution blown out from the safety valve 2 is attached and the detecting element 90 is The disconnection can be determined, and it can be detected that the safety valve 2 has been broken.

  The lithium secondary battery module 8 according to the present embodiment can issue a warning or stop charging / discharging when it detects the cleavage of the safety valve 2. As a result, it is possible to minimize the damage caused by the electrolytic solution and the decomposition gas scattered from the inside of the battery, and thus it is possible to provide a highly safe battery module.

(Example 2)
First, in the same manner as in Example 1, a lithium secondary battery 1 is manufactured, and is bound by a pair of restraining plates 3 and 3 made of aluminum and a restraining band 4 made of iron, and five lithium secondary batteries 1 are integrated. did.

  And the duct member 55 comprised with insulating members, such as resin (a polypropylene in a present Example), was fixed to the restraining plate 3 made from aluminum. The duct member 55 has a box shape extending in the direction in which the lithium secondary batteries 1 are arranged, and the bottom surface 55 a abuts the top surface of the lithium secondary battery 1. The duct member 55 has a through hole 550 at a position corresponding to the safety valve 2 provided on the upper surface of the lithium secondary battery 1, and discharges internal gas to one side surface in the direction in which the lithium secondary battery 1 is arranged. A discharge hole 551 is opened. That is, in the duct member 55 fixed to the five integrated lithium secondary batteries 1, the decomposition gas of the electrolyte sprayed from the safety valve 2 of each lithium secondary battery 1 flows into the inside from the through hole 550, The introduced decomposition gas is collected and discharged from the discharge hole 551.

  A detection element 90 similar to that in the first embodiment is disposed on the inner peripheral surface of the duct member 55 and the surface facing the discharge hole. The detection element 90 is connected to the resistance change detection means 7 as in the first embodiment.

  In this way, the lithium secondary battery module 8 of this example could be manufactured. The lithium secondary battery module 8 of the present example is shown in FIGS. FIG. 5 is a diagram showing the lithium secondary battery module 8 of the present embodiment, and FIGS. 6 to 7 are diagrams showing the configuration of the duct member 55.

  Since the lithium battery module 8 of the present embodiment has a configuration in which the through hole 550 of the duct member 55 and the safety valve 2 communicate with each other, the electrolytic solution scattered from the safety valve 2 is provided inside the duct member 55 and is detected by the detection element 90. Electrolyte adheres to the surface. Thereby, similarly to the case of the first embodiment, the cleavage of the safety valve 2 can be detected.

  In the lithium secondary battery module 8 according to the present embodiment, the duct member 55 collects the electrolytic solution scattered from the safety valve 2, so that the electrolytic solution is more easily attached to the detection element 90. Further, the duct member 55 collects the decomposition gas of the electrolytic solution scattered from the safety valve 2, thereby collecting and safely discharging the decomposition gas having high reactivity and flammability. Improved safety.

(Example 3)
First, in the same manner as in Example 1, a lithium secondary battery 1 is manufactured, and is bound by a pair of restraining plates 3 and 3 made of aluminum and a restraining band 4 made of iron, and five lithium secondary batteries 1 are integrated. did.

Then, both ends of a belt-like fixing base made of an insulating resin (polypropylene in this embodiment) are fixed to the pair of restraining plates 3 and 3. The fixed base 50 is arranged opposite to the safety valve 2 at a position spaced apart from each safety valve 2 of the five lithium ion secondary batteries 1, and the surface of the fixed base 50 facing the safety valve 2 is placed on the surface of the semiconductor gas sensor. The semiconductor gas sensor was arranged so that the detection unit 95 (made of SnO ₂ in this embodiment) is located.

This semiconductor gas sensor was connected to the resistance change detecting means 7. Resistance change detecting means 7 constructed a series circuit by connection detection unit 95 of the gas sensor 13 (R ₂₎ and a fixed resistor (R ₁₎ in series. Then, a constant voltage is applied between the series circuits, and the variation of the voltage flowing through the fixed resistor (R ₁ ) is monitored. Here, since the temperature used as a sensor is high (200-400 degreeC), a semiconductor gas sensor has a heater which heats the detection part 95. FIG. This heater (fixed resistance (R ₃ )) is also connected to the resistance change detecting means 7, and is connected in an electrically parallel state with a series circuit in which the detection unit 95 (R ₂ ) and the fixed resistance (R ₁ ) are connected in series. Was built circuit. The resistance change detecting means 7 of this embodiment is an example of a means for detecting a resistance change in the detection unit (R _2), but is not limited only to this embodiment.

  In this way, the lithium secondary battery module 8 of this example could be manufactured. The lithium secondary battery module 8 of the present example is shown in FIGS. 8 and 9 are diagrams showing the lithium secondary battery module 8 of the present embodiment, and FIG. 10 is a diagram showing a circuit of the resistance change detecting means 7.

(Operation)
The operation of the lithium secondary battery module 8 of this embodiment will be described below.

  The lithium secondary battery module 8 of the present embodiment is a battery module in which five lithium secondary batteries 1 are connected in series, and can be charged and discharged in the same manner as a normal battery module.

  Then, in one of the lithium secondary batteries 1 constituting the lithium secondary battery module 8 of the present embodiment, an abnormality such as overcharge or internal short circuit occurs, and a decomposition gas of the electrolyte is generated in the battery container. When cracked gas is generated, the internal pressure of the battery container increases, and the safety valve 2 is opened when the pressure exceeds a predetermined pressure.

When the safety valve 2 is cleaved, the decomposition gas of the electrolytic solution is ejected from the safety valve 2. The cracked gas ejected from the safety valve 2 is sprayed to and abuts (attaches) to the fixed base 50 and the detection unit 95 disposed at positions facing each other with a small interval. The cracked gas contains a reducing gas (H ₂ , CH _4, etc.), and when it adheres to the detection unit 95, the electrical resistance of the detection unit 95 decreases.

When the electrical resistance of the detection unit 95 decreases, the voltage flowing through the fixed resistance (R ₁ ) in the resistance change detection means 7 increases greatly. In this embodiment, the resistance change detecting means 7 detects this voltage increase.

In the lithium secondary battery module 8 of this embodiment, when the resistance change detecting means 7 detects an increase in the voltage flowing through the fixed resistance (R ₁ ), it is determined that the decomposition gas blown out from the safety valve 2 has adhered to the detection unit 95. It is possible to detect that the safety valve 2 has been cleaved.

  As in the case of the first embodiment, the lithium secondary battery module 8 of the present embodiment can issue a warning or stop charging and discharging when it detects the breakage of the safety valve 2. As a result, it is possible to minimize damage caused by the electrolytic solution and decomposition gas scattered from the inside of the battery, and thus it is possible to provide a highly safe battery module.

Example 4
First, the lithium secondary battery 1 is manufactured in the same manner as in Example 3, and the five lithium secondary batteries 1 are integrated by being restrained by a pair of restraining plates 3 and 3 made of aluminum and a restraining band 4 made of iron. did.

  And the duct member 55 comprised with insulating members, such as resin (a polypropylene in a present Example), was fixed to the restraining plate 3 made from aluminum. The duct member 55 has a box shape extending in the direction in which the lithium secondary batteries 1 are arranged, and the bottom surface 55 a abuts the top surface of the lithium secondary battery 1. The duct member 55 has a through hole 550 at a position corresponding to the safety valve 2 provided on the upper surface of the lithium secondary battery 1, and discharges internal gas to one side surface in the direction in which the lithium secondary battery 1 is arranged. A discharge hole 551 is opened. That is, in the duct member 55 fixed to the five integrated lithium secondary batteries 1, the decomposition gas of the electrolyte sprayed from the safety valve 2 of each lithium secondary battery 1 flows into the inside from the through hole 550, The introduced decomposition gas is collected and discharged from the discharge hole 551.

  Then, on the inner peripheral surface of the duct member 55 and the surface facing the through hole 550, the same detection unit 95 as that in the third embodiment is disposed. The detection unit 95 is connected to the resistance change detection means 7 as in the third embodiment.

  In this way, the lithium secondary battery module 8 of this example could be manufactured. A lithium secondary battery module 8 of this example is shown in FIGS. FIG. 11 is a view showing the lithium secondary battery module 8 of the present embodiment, and FIG. 12 is a view showing the configuration of the duct member 55.

  The lithium battery module 8 of the present embodiment has a configuration in which the through-hole 550 of the duct member 55 and the safety valve 2 communicate with each other, so that the decomposition gas scattered from the safety valve 2 is provided inside the duct member 55. 95. Thereby, similarly to the case of the third embodiment, the cleavage of the safety valve 2 can be detected.

  In the lithium secondary battery module 8 of the present embodiment, the duct member 55 collects the decomposition gas blown out from the safety valve 2, so that the decomposition gas is more easily attached to the detection unit 95. Further, the duct member 55 collects the decomposed gas scattered from the safety valve 2, thereby collecting the reactive and flammable decomposed gas and discharging it safely, and the lithium secondary battery module 8 is safe. Improved.

1 is a diagram showing a configuration of a lithium secondary battery used in a lithium secondary battery module of Example 1. FIG. 1 is a diagram showing a configuration of a lithium secondary battery module of Example 1. FIG. 1 is a side view showing a configuration of a lithium secondary battery module of Example 1. FIG. FIG. 3 is a diagram showing a circuit of resistance change detection means of the lithium secondary battery module of Example 1. 4 is a diagram showing a configuration of a lithium secondary battery module of Example 2. FIG. 6 is a view showing a duct member of the lithium secondary battery module of Example 2. FIG. FIG. 4 is a diagram illustrating a configuration of a duct member of a lithium secondary battery module according to Example 2. 6 is a diagram showing a configuration of a lithium secondary battery module of Example 3. FIG. 6 is a side view showing the configuration of a lithium secondary battery module of Example 3. FIG. It is the figure which showed the circuit of the resistance change detection means of the lithium secondary battery module of Example 3. FIG. 6 is a diagram showing a configuration of a lithium secondary battery module of Example 4. FIG. 6 is a diagram showing a configuration of a duct member of a lithium secondary battery module according to Example 4. FIG.

Explanation of symbols

1: lithium secondary battery 10: wound electrode body 11: positive electrode plate 12: negative electrode plate 14: battery container 140: lid body 141: container body 2: safety valve 3: restraint plate 4: restraint band 50: fixing base 55: Duct member 550: Through hole 551: Discharge hole 6: Electrode terminal 60: Positive electrode terminal 61: Negative electrode terminal 7: Resistance change detection means 8: Lithium secondary battery module 90: Detection element 95: Detection unit

Claims (2)

A plurality of power storage elements having a power storage element container provided with a pressure release mechanism that seals the electrode body together with the electrolyte and opens when the internal pressure becomes a predetermined pressure or higher to reduce the internal pressure. Are electrically connected storage element modules,
A substantially linear shape made of a conductive polymer at a position where the electrolytic solution discharged from the pressure release mechanism can come into contact when the pressure in the storage element container becomes equal to or higher than a predetermined pressure. And a detecting device that detects a change in electrical resistance caused by disconnection of the linear member due to contact with the electrolytic solution . The power storage element module according to claim 1 , wherein the conductive polymer is polythiophene that is soluble in the electrolytic solution .

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