JP2005149951A - Short circuit control element, bipolar battery, battery pack, battery module, and vehicle mounting them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a short circuit control element preventing performance degradation of a device even if abnormality arises in a unit cell and also preventing complication of constitution of the device. <P>SOLUTION: The short circuit control device is installed between a positive terminal 100 and a negative terminal 102 of the unit cell, controls the short circuit of the unit cell, and has a first element 1 short-circuiting the unit cell by voltage on the outside of the specified range. The first element 1 is arranged on the positive terminal 100 side, and contains: a first conductive layer 10 formed with a valve metal having conductivity; a second conductive layer 14 installed on the first conductive layer 10 and having conductivity; and an insulating oxide film layer 11 formed on the surface of the first conductive layer 10 on the negative electrode 102 side so as not to come in contact with the first conductive layer and the second conductive layer, and broken by voltage on the outside of the specified range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a short-circuit control element that controls a short circuit of a battery, a single cell including the protection element, a battery pack in which a plurality of the battery cells are connected, a battery module in which a plurality of battery packs are connected, the battery cell, a battery pack, and a battery The present invention relates to a vehicle equipped with a module.

  In a conventional battery module in which a plurality of unit cells are connected in series, when a defect occurs in one of the unit cells, the internal resistance increases and the state of charge of the unit cells becomes abnormal. In this case, stable charging / discharging cannot be performed, and the entire module cannot be used.

  In order to prevent this, there is an invention in which a changeover switch is provided before and after the battery, the unit cell in which an abnormality has occurred is electrically disconnected from the battery module, and the insufficient voltage is compensated by a booster circuit (see Patent Document 1).

However, in the present invention, since a booster circuit is required, there is a problem that the module impedance is increased, and as a result, the current value is decreased, leading to a decrease in module performance. Moreover, in the said invention, in order to monitor the voltage of each single cell and to detach | detach a single cell as needed, a complicated circuit is needed and control will also become complicated. This increases the cost.
JP-A-6-283210

  The present invention has been made in view of the above problems, and a short-circuit control element that can prevent deterioration in the performance of a device even when an abnormality occurs in a single cell and that does not complicate the configuration of the device, and a bipolar including the protection device An object is to provide a battery, an assembled battery, a battery module, and a vehicle on which these are mounted.

  (1) A short-circuit control element that is disposed between a positive electrode terminal and a negative electrode terminal of a unit cell and controls a short circuit of the unit cell, and includes a first element that short-circuits the unit cell by a voltage outside a predetermined range, The first element is disposed on the positive electrode terminal side, and is formed of a conductive valve metal, a first conductive layer formed on the first conductive layer, and a conductive second conductive layer, An insulating oxide film layer formed on the surface of the first conductive layer on the negative electrode terminal side so as not to contact the first conductive layer and the second conductive layer, and destroyed by a voltage outside a predetermined range; A short-circuit control element comprising:

  (2) A plurality of short-circuit control elements according to any one of claims 1 to 20, a plurality of single battery layers connected in parallel for each of the short-circuit control elements, the short-circuit control elements, and the single A bipolar battery, wherein the plurality of single battery layers are connected in series.

  (3) An assembled battery, wherein the short-circuit control elements according to any one of claims 1 to 20 are connected in parallel for each unit cell, and a plurality of the unit cells are connected.

  (4) A battery module comprising a plurality of the assembled batteries according to any one of claims 22 to 25 connected in parallel and / or in series.

  (5) As a vehicle power supply, the bipolar battery according to claim 21, the assembled battery according to any one of claims 22 to 25, or the battery module according to claim 26 is mounted. vehicle.

  (1) Since the first element of the short-circuit control element has an oxide film layer that is easily broken by a voltage outside a predetermined range, the unit cell is externally short-circuited when the voltage becomes a predetermined value or more. At this time, the current passes from the positive terminal of the cell to the negative terminal via the short-circuit control element.

  Therefore, for example, when a plurality of cells having the short-circuit control element of the present invention are connected to form an assembled battery, and one voltage of the cell rises to a predetermined value or more, the cell is short-circuited by the short-circuit control element. Be made. A current flows by avoiding the unit cell in which an abnormality has occurred. As a result, the battery characteristics of the assembled battery are stabilized without being adversely affected by the unit cell in which an abnormality has occurred. Furthermore, since a short-circuit control element is only provided between the positive and negative electrodes of the unit cell, a special control device or the like is not required, the configuration is easy, and the cost can be reduced.

  In addition, even when a short circuit occurs in one of the cells in the assembled battery, and this causes an overdischarge and the voltage drops abnormally, the cell is short-circuited by the short-circuit control element. As a result, the battery characteristics of the assembled battery are stabilized without being adversely affected by the unit cell in which an abnormality has occurred.

  (2) Since the short-circuit control element is connected to the single battery layer in the bipolar battery, when an abnormality occurs in one of the single battery layers, only the single battery layer is short-circuited, and the other single battery layer is connected. It can prevent adverse effects.

  (3) Since the short-circuit control element is connected in parallel for each unit cell, when an abnormality occurs in one of the unit cell layers, only the unit cell layer is short-circuited, and the other unit cell layers are adversely affected. It can prevent giving.

  (4) Since a plurality of assembled batteries having a short-circuit control element are connected, a battery module with high reliability and a simple structure can be provided.

  (5) Since the assembled battery or battery module having the short-circuit control element is mounted, a vehicle having a highly reliable and stable vehicle power source can be obtained.

  The present invention is a short-circuit control element that is disposed between a positive electrode terminal and a negative electrode terminal of a unit cell and controls a short circuit of the unit cell. The short-circuit control element of the present invention includes at least one of the first element shown in FIG. 1 and the second element shown in FIG. 2 in order to control the short-circuit of the unit cell.

<First element>
FIG. 1 is a cross-sectional view of the first element.

  As shown in FIG. 1, the first element 1 includes a first conductive layer 10 disposed on the positive electrode terminal side of the battery, and a first conductive layer 10 formed on the first conductive layer 10 and made of a conductive metal. The oxide film layer 11 formed on the surface of the first conductive layer 10 on the negative electrode terminal side of the battery, and the oxide film layer 11 so that the two conductive layers 14 do not contact the first conductive layer 10 and the second conductive layer 14. And a current collecting material layer 12 disposed between the second conductive layers 14.

  The first conductive layer 10 is made of a valve metal having conductivity. As the valve metal, for example, it is preferable to use a metal containing at least one of tantalum (Ta), niobium (Nb), and aluminum (Al). These valve metals are because the oxide film can be easily formed by anodic oxidation, and the formed oxide film has high insulation. In addition, when the insulating property of the oxide film is low, self-discharge is likely to occur, and it is not suitable for application to a unit cell.

  In general, when a battery is overdischarged, the voltage rapidly drops from the operating voltage to an arbitrary voltage of 0 V or less. The oxide film of tantalum and niobium is extremely weak against a reverse voltage and is destroyed at about −1 to 0V. Therefore, in order to detect the overdischarge by short-circuiting the cell when overdischarge occurs, it is preferable to apply tantalum and niobium as the valve metal to the first conductive layer 10.

  The oxide film layer 11 is formed by anodizing the surface of the valve metal of the first conductive layer 10 and has an insulating property. Anodizing is a technique in which a valve metal is immersed in an electrolytic solution and is oxidized by energizing the anode. According to this method, a current flows through a defect portion of the oxide film on the surface, and the defect portion is repaired by the oxide film. Since the defect portion disappears, in the oxide film layer 11 to be formed, the breakdown voltage (withstand voltage) is always proportional to the thickness at a constant rate. Therefore, the withstand voltage of the oxide film layer 11 can be easily adjusted with high accuracy by adjusting the thickness of the oxide film layer 11. When the oxide film is formed by a method other than anodic oxidation, the generation of minute defects cannot be prevented. Therefore, in the present invention, the oxide film layer 11 obtained by anodic oxidation is used.

As described above, the oxide film such as Ta ₂ O ₅ , Nb ₂ O ₅ , and Al ₂ O ₃ has a proportional relationship between the film thickness (nm) and the withstand voltage (V). Specifically, this relationship is about 1.0 to 1.5 nm / V. When the operating voltage of the unit cell is about 1 to 10 V, the oxide film layer 11 preferably has a thickness of 1 nm to 10 nm.

  If the oxide film layer 11 is too thick, the first element 1 does not operate even in an overcharged state, and if it is too thin, the first element 1 is short-circuited at a voltage within the normal operating range and cannot be operated effectively. For this reason, as described above, when the normal operating range of the unit cell is 1 to 10 V, the thickness of the oxide film layer 11 is preferably in the range of 1 to 10 nm.

The current collecting material layer 12 is formed of an electron conductive or ion conductive current collecting material. Examples of the current collecting material include metal paste, carbon paste, graphite paste, polyaniline, polypyrrole, polyaniline, polypyrrole, polythiophene, or derivatives thereof, β-MnO ₂ , tetrathiafulvalene, tetracyanoquinodimethane, or their Contains a mixture.

  The current collecting material layer 12 is interposed between the oxide film layer 11 and the second conductive layer 14 in order to prevent destruction of the oxide film layer 11 due to an impact when the second conductive layer 14 is placed on the oxide film layer 11. Has been.

<Short-circuit control element 3>
Next, the case where the short-circuit control element 3 including the first element 1 is applied to a single cell will be described.

  FIG. 2 is a cross-sectional view illustrating a state in which the short-circuit control element including the first element is applied to the single battery. In FIG. 2, the main body of the unit cell is omitted, and only the positive electrode terminal 100 and the negative electrode terminal 102 are shown.

  When applied to a unit cell, the first element 1 is disposed between the positive electrode terminal 100 and the negative electrode terminal 102 while being protected by the insulating exterior 104. The reason why the exterior 104 is provided is to prevent the unit cell from being short-circuited for reasons other than the destruction of the oxide film layer 11 of the first element 1.

  Here, when the voltage between the positive electrode terminal 100 and the negative electrode terminal 102 of the unit cell is outside a predetermined range (for example, outside the range of 1 to 10 V in the above example), the oxide film layer 11 is destroyed. Due to this destruction, the first conductive layer 10 and the second conductive layer 14 are electrically connected via the current collecting material layer 12. Since the first element 1 becomes conductive, a bypass passage is formed between the positive electrode terminal 100 and the negative electrode terminal 102 of the unit cell.

  As described above, the short-circuit control element 3 incorporating the first element 1 has an oxide film layer that can be easily broken by a voltage outside a predetermined range. Shorted. At this time, the current passes from the positive electrode terminal of the unit cell to the negative electrode terminal via the short-circuit control element 3.

  Therefore, for example, even when the unit cell is broken and the voltage rises above or falls below the normal working range and adversely affects the apparatus, the unit cell is short-circuited by the short-circuit control element 3, The adverse effect of the battery on the device can be prevented. Furthermore, since the short-circuit control element 3 is simply provided between the positive and negative electrodes of the unit cell, a special control device or the like is not required, the configuration is easy, and the cost can be reduced.

<Second element>
FIG. 3 is a sectional view of the second element.

  As shown in FIG. 3, the second element 2 includes a third conductive layer 20 disposed on the positive electrode terminal side of the unit cell, a fourth conductive layer 22 disposed on the negative electrode terminal side of the unit cell, and a third element 2. The fifth conductive layer 24 disposed between the conductive layer 20 and the fourth conductive layer 22 and the third conductive layer 24 so that the fifth conductive layer 24 does not contact at least one of the third conductive layer 20 and the fourth conductive layer 22. And an insulating insulating layer 26 disposed between the conductive layer 20 and the fourth conductive layer 22.

  The third conductive layer 20 and the fourth conductive layer 22 are both formed from a conductive metal.

  The fifth conductive layer 24 has a spring structure in which a force in a direction approaching at least one of the third conductive layer and the fourth conductive layer acts. The elastic force of the fifth conductive layer 24 shown in FIG. 3 is restricted by the insulating layer 26 so that it cannot contact the fourth conductive layer 22 before the insulating layer 26 described later is melted. Although FIG. 3 shows an example in which a metal thin plate is bent to form a spring structure, the present invention is not limited to this. The fifth conductive layer 24 may be formed by bending a metal thin plate or creating a minute spring.

  The fifth conductive layer 24 may be formed of a shape memory alloy that stores a shape that contacts at least one of the third conductive layer 20 or the fourth conductive layer 22. Shape memory alloys include Ti—Ni, Ni—Mn—Ga, Ti—Ni—Cu, Ti—Pd—Ni, Cu—Zn—Al, Au—Cd, Cu—Al—Ni, Fe—Mn—Si, Fe-Pt, Fe-Ni-Co-Ti, Fe-Ni-C, Fe-Cr-Ni-Mn-Si, Fe-Pd, etc. are mentioned.

  The insulating layer 26 is formed in a film shape from a thermoplastic resin so as to melt when heated to a predetermined temperature or higher. Here, the thermoplastic resin uses at least one resin selected from polyolefin, ethylene-unsaturated carboxylic acid copolymer, styrenic block copolymer (SBC), polyamide, polyacryl, polyurethane and polyester. It is. If these resins are used, the insulating layer 26 can be formed at low cost. Since the insulating layer 26 is in the form of a film, the insulating layer 26 that can be easily broken by heating can be formed. In addition, the thermoplastic resin is easy to process into a thin film and is easy to handle.

  The insulating layer 26 is preferably formed of a porous material. By using a porous insulating material, the escape place of the molten insulating layer 26 can be made, and a short circuit can be surely caused.

  The insulating layer 26 is preferably formed by combining the above thermoplastic resins so that the melting point is in the range of 60 ° C to 150 ° C. Since a general non-aqueous electrolyte battery operates near room temperature, the insulating layer 26 can be reliably melted when the unit cell is defective by setting the melting point temperature to a temperature far from the room temperature. On the other hand, if the melting point temperature is set too high, the single cell is defective, but the insulating layer 26 does not melt and the second element 2 cannot be operated. Is not preferred.

  Although not illustrated, the insulating layer 26 preferably includes a powdery conductive material, a conductive material encapsulated with an insulating material, or a conductive material formed in a thin film shape. By including these conductive materials, when the insulating layer 26 is melted, the third conductive layer 20 and the fourth conductive layer 22 are more reliably electrically connected via the fifth conductive layer 24. Note that the insulating layer 26 has a small amount of conductive material or is encapsulated with an insulating material, and therefore naturally does not pass current before melting.

<Short-circuit control element 4>
Next, a case where the short-circuit control element 4 including the second element 2 and the first element 1 is applied to a single cell will be described.

  FIG. 4 is a cross-sectional view showing a state in which the short-circuit control element composed of the first element and the second element is applied to the cell, and FIG. 5 is a cross-sectional view showing the state of the short-circuit control element when an abnormality occurs in the cell. 6 is a cross-sectional view showing a state of the short-circuit control element following FIG. 4 to 6, the main body of the unit cell is omitted, and only the positive electrode terminal 100 and the negative electrode terminal 102 are shown.

  FIG. 4 shows a state in which the short-circuit control element 4 formed by combining the first element 1 and the second element 2 described above is applied to a single cell. The first element 1 and the second element 2 are formed by making the third conductive layer 20 and the fifth conductive layer 24 of the second element 2 U-shaped, and the second conductive layer 14 and the second element of the first element 1 By sharing the second fourth conductive layer 22, the first element 1 and the second element 2 are connected in parallel. The short-circuit control element 4 is protected by an insulating exterior 104 where the end of each layer is exposed.

  In this way, the short-circuit control element 4 including the first element 1 and the second element 2 is first shown when the voltage between the positive electrode terminal 100 and the negative electrode terminal 102 of the applied cell is out of a predetermined range. As shown in FIG. 5, the oxide film layer 11 is destroyed, and the first conductive layer 10 and the current collecting material layer 12 come into contact with each other. As a result, a current flows from the positive electrode terminal 100 to the negative electrode terminal 102 via the third conductive layer 20, the first conductive layer 10, the current collecting material layer 12, and the second conductive layer 14. A single cell is short-circuited.

  Here, when only a part of the oxide film layer 11 is destroyed by the voltage outside the predetermined range, the resistance of the short-circuit control element 4 is large, and the short-circuit control element 4 generates heat. The insulating layer 26 of the short-circuit control element 4 is heated by the heat generation. The insulating layer 26 begins to melt when heated to a predetermined temperature.

  When the insulating layer 26 is melted, the posture of the fifth conductive layer 24 is not restricted by the insulating layer 26, and the third conductive layer 20 and the fifth conductive layer 24 are in contact with each other as shown in FIG. As a result, a current flows from the positive electrode terminal 100 to the negative electrode terminal 102 via the third conductive layer 20, the fifth conductive layer 24, and the second conductive layer 14 (fourth conductive layer 22). The cell is completely shorted.

  As described above, according to the short-circuit control element 4 in which the first element 1 and the second element 2 are combined, the application of a voltage outside the predetermined range causes the first element 1 to cause a short circuit of the unit cell. Here, when the oxide film layer 11 is not sufficiently broken, the insulating layer 26 of the second element 2 is melted by heat generated by the internal resistance, and the second element 2 causes a complete short circuit of the unit cell. Therefore, according to the short-circuit control element 4, the unit cell in which an abnormality has occurred can be completely short-circuited in two stages.

  Although only the first element 1 short-circuits the unit cell in which an abnormality has occurred, the resistance value is not necessarily small. Therefore, when a short circuit occurs in a relatively high resistance state, the current that flows when the battery is charged and discharged May not be able to flow all of the current, and there is a possibility that current may flow to the unit cell in which an abnormality has occurred. In this case, there is a possibility that the abnormal unit cell is overcharged and in a dangerous state. However, in the case of the short-circuit control element 4 to which the second element 2 is added, the resistance of the short-circuit control element 4 can be made extremely small due to the short circuit of the second element 2 without adversely affecting the apparatus.

  FIG. 4 shows an example in which the first element 1 is combined with the second element 2 and applied to the single battery as the short-circuit control element 4. However, a short-circuit control element including only the second element 2 can also be applied. In this case, the insulating layer 26 of the second element 2 is melted due to heat generation of the overcharged or overdischarged unit cell, and the third conductive layer 20 and the fourth conductive layer 22 are interposed via the fifth conductive layer 24. Are electrically connected. Thereby, the cell in which the defect has occurred is brought into an external short circuit state.

  Next, the example which applies the above-mentioned short circuit control elements 3 and 4 to the apparatus using a single cell is demonstrated.

<Application example 1>
FIG. 7 is a block diagram of an apparatus to which the short-circuit control element is applied.

  The device 5 of the application example 1 includes a single battery 50, a load (for example, a motor) 51, a charging power source 52, a voltage detector 53, a current control device 54, and a battery controller 55.

  The single battery 50 is connected with the above-described short-circuit control element 4 in parallel, and is enclosed in the same exterior. A resistor 58 is connected in series to the short-circuit control element 4.

  The unit cell 50 is connected to the motor 51 via the switch 56 and to the charging power source 52 via the switch 57. The switches 56 and 57 are controlled by the battery controller 55. When the cell 50 is discharged, the switch 56 is closed, the switch 57 is opened, and current is supplied to the motor 51. When charging the unit cell 50, the switch 56 is opened, the switch 57 is closed, and a current is supplied from the charging power source 52 to the unit cell 50.

  A voltage detector 53 is connected to the cell 50 in parallel. The battery controller 55 adjusts the current supplied to each unit based on the detection result of the voltage detector 53.

  By repeatedly using the device having such a configuration, when charging / discharging of the unit cell 50 is repeated, the internal resistance of the unit cell 50 may gradually improve, resulting in overcharge or overdischarge. When a high voltage is caused by overcharging or a reverse voltage is caused by overdischarging, the unit cell 50 is short-circuited by the function of the short-circuit control element 4 described above.

  Therefore, for example, an abnormal burden is not applied to the motor 51. Thus, by incorporating the short-circuit control element 4 of the present invention into the device, it is possible to prevent the unit cell 50 in which an abnormality has occurred from adversely affecting other configurations.

  In Application Example 1, since the unit cell 50 and the short-circuit control element 4 are included in the same exterior, wiring for connecting the unit cell 50 and the short-circuit control element 4 does not go out of the exterior, and the device Can be simplified.

  Further, since the resistor 58 is connected in series to the short-circuit control element 4, even if the short-circuit control element 4 is activated by overcharging and the single cell 50 is short-circuited, the stored energy is not released at a stretch in a short time. Therefore, abnormal heat generation due to Joule heat can be prevented, and discharge can be performed relatively quickly. The resistor 58 preferably has a resistance value (for example, 100 mΩ to 100Ω) such that a current of about 100 mA to 10 A flows when the short-circuit control element 4 is at a voltage that does not short-circuit the unit cell 50.

<Application example 2>
FIG. 8 is a block diagram of an apparatus to which the short-circuit control element is applied, and FIG. 9 is a cross-sectional view showing the internal structure of the bipolar battery. The same components as those in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted.

  In the device 6 of the application example 2, a bipolar battery 60 is attached instead of the unit cell 50 of the device 5 shown in FIG. 7, and a voltage detection for detecting one voltage of the unit cell layer 60a in the bipolar battery 60 is performed. A container 61.

  The bipolar battery 60 has a plurality of single battery layers 60a connected in series inside. As shown in FIG. 9, the unit cell layer 60 a includes a negative electrode active material layer 62, an electrolyte layer 63, and a positive electrode active material layer 64. A current collector 65 is sandwiched between the unit cell layers 60a, and the unit cell layers 60 are connected in series. A plurality of short-circuit control elements 4 are arranged between the current collectors 65. Thereby, the short circuit control element 4 is connected in parallel with each single cell layer 60a.

  The current collectors 65 in the outermost layer of the stack are drawn out of the casing of the bipolar battery 60 and used as the positive electrode terminal 65a and the negative electrode terminal 65b.

  The second current collector 65 from the lowest layer is provided with a detection line 66 for voltage detection, and the detection line 66 is also drawn out of the casing of the bipolar battery 60. The detection line 66 is connected to the voltage detector 61. Thus, by pulling out the detection line 66, the voltage of one unit cell layer 60a in the bipolar battery 60 is detected.

  The device 6 operates by charging / discharging the bipolar battery 60 in the same manner as the device 5 shown in FIG. When an abnormality occurs in any of the unit cell layers 60a due to charging / discharging, the short-circuit control element 4 operates to short-circuit the unit cell layer 60a in which the abnormality occurs. Each time the abnormality occurs in the unit cell layer 60a, the unit cell layer 60a is short-circuited by the short-circuit control element 4.

  In the device 6, the voltage of the entire bipolar battery 60 is detected by the voltage detector 53, and the voltage of one unit cell layer 60 a is detected by the voltage detector 61. The battery controller 55 can calculate how many single cell layers 60a are operating normally instead of being short-circuited by dividing the voltage of the entire bipolar battery 60 by the voltage of one single cell layer 60a.

  Based on this calculation, for example, the battery controller 55 can display that it is time to replace the bipolar battery 60 on a display device (not shown). As a timing for displaying the replacement time, for example, a time when the number of unit cell layers 60a equal to or more than the number of unit cell layers 60a connected in advance is short-circuited can be considered. Further, it is possible to predict the replacement time of the bipolar battery 60 based on the above calculation.

  As described above, the short-circuit control element 4 can also be applied to the bipolar battery 60 in which the plurality of single battery layers 60a are connected in series. Since the short-circuit control element 4 is simply provided in the casing of the bipolar battery 60, the defective single cell layer 60a is automatically short-circuited. Therefore, the voltage of each single cell layer 60a is detected and the capacity is uneven. It is not necessary to draw an unnecessarily many voltage detection lines from each single cell layer 60a for monitoring. The configuration of the bipolar battery 60 can be simplified.

<Application example 3>
FIG. 10 is a block diagram of an apparatus to which the short-circuit control element is applied. Components similar to those in FIG. 7 or FIG.

  In the device 7 of the application example 3, a plurality of unit cells 70 are connected in series to form an assembled battery. The device 6 and the device 7 are different from each other in that the bipolar battery 60 of the device 6 is replaced with an assembled battery, that is, the single cell layer 60a in the bipolar battery 60 is replaced with the single cell 70. . The unit cell 70 may be a unit cell having a single layer structure, or may be a unit cell having a multilayer structure such as the bipolar battery 60.

  When one voltage of the unit cell 70 constituting the assembled battery rises to a predetermined value or more, the unit cell 70 is short-circuited by the short-circuit control element 4. A current flows avoiding the unit cell 70 in which an abnormality has occurred. As a result, the battery characteristics of the assembled battery are stabilized without being adversely affected by the unit cell in which an abnormality has occurred. Furthermore, since only a short-circuit control element is provided between the positive and negative electrodes of the unit cell 70, a special control device or the like is not required, the configuration is easy, and the cost can be reduced.

  Further, even when a minute short circuit occurs in one of the unit cells 70 in the assembled battery, and this causes an overdischarge and the voltage drops abnormally, the unit cell 70 is short-circuited by the short-circuit control element 4. As a result, the battery characteristics of the assembled battery are stabilized without being adversely affected by the unit cell 70 in which an abnormality has occurred.

  In addition, the number of unit cell layers 60a connected in series is extra by one or more and 30% or less of the number of series connections than the number of series connections from which the voltage required for the operation of the device 7 is obtained. They are connected in series. In general, the fully charged voltage and the discharged voltage of the secondary battery differ by about 30%. Therefore, if it is up to 30% of the number of originally required single cells 70, it is possible to connect the single cells 70 in series without increasing the maximum output voltage and preventing charging / discharging.

  Thus, by connecting redundant cells 70 to provide redundancy, even if some abnormality occurs and some of the cells 70 are short-circuited by the short-circuit control element 4, they are necessary for the operation of the device 7. Voltage can be obtained. Since the voltage necessary for the operation of the device 7 can be obtained even after an abnormality occurs in the unit cell 70, the reliability can be improved.

  Regarding reliability, specifically, for example, when 100 cells are connected in series without redundancy, when the failure rate per cell is 1000 ppm, the failure rate of the entire assembled battery is 9.1%. It becomes. However, when one extra cell is added and 101 are connected in series, the defect rate is reduced to 0.90%. Furthermore, when 105 are connected in series, it can be seen that 0.00082% = 8.2 ppm and extremely high reliability is obtained. However, as mentioned above, it should be noted that the required voltage does not exceed 30% or more.

  In addition, although not shown in figure, it can also be set as a battery module by combining multiple assembled batteries which applied said short circuit control element 4 to each single battery. According to such a battery module, a battery having a simple configuration and high reliability can be obtained. If a battery module is formed by connecting battery packs in series, a plurality of battery packs are prepared in order to obtain a required voltage, so that the voltage of each battery pack is reduced and the handling can be facilitated. . Further, if the assembled batteries are connected in parallel to form a battery module, the reliability can be improved.

<Application example 4>
FIG. 11 is a cross-sectional view of a unit cell.

  As a single cell applied to the device 5 or the device 7 as shown in FIG. 7 or FIG. 10, a single cell 80 as shown in FIG. 11 can be considered.

  In the unit cell 80, the unit cell layer 80 a sandwiching the current collector 85 has a negative electrode active material layer 82, an electrolyte layer 83, and a positive electrode active material layer 84 stacked vertically symmetrically in the stacking direction. Thus, the stacked unit cell layers 80a are electrically connected to each other in parallel. Here, the short circuit control element 4 is provided in the single battery 80.

  Therefore, when a failure occurs in all the unit cell layers 80a connected in parallel, the short-circuit control element 4 operates and the unit cell 80 is short-circuited.

  As described above, the short-circuit control element of the present invention can be applied to a single cell in which the internal cell layers 80a are connected in parallel.

  In addition, in the said application examples 1-4, although the short circuit control element 4 is used, it cannot be overemphasized that the short circuit control element 3 may be used.

  Moreover, although the said application examples 1-4 demonstrated the case where the short circuit control element 4 which contains the 1st element 1 and the 2nd element 2 one by one was demonstrated, it is not limited to this. A short-circuit control element including a plurality of first elements 1 and second elements 2 can also be used. As a result, even if one of the first element 1 or the second element 2 is defective, the other single element 1 or the second element 2 can reliably and safely short-circuit the defective cell. it can.

  Further, when a plurality of the first element 1 and the second element 2 are included in the short-circuit control element, the oxide film layer 11 is destroyed by different voltages for the first element 1, and the insulating layer 26 has a different temperature for the second element 2. Can be set to be melted. In this way, by setting different settings for the short-circuit control element to operate for short-circuiting of the single cell, for example, an element that operates in the case of overcharge and an element that operates in the case of overdischarge The range can be different. As a result, the short-circuit control element can be operated more reliably and appropriately.

  The unit cell, the assembled battery, and the battery module to which the short-circuit control element of the present invention as described above is applied can be applied to an electric vehicle, a hybrid electric vehicle, and a fuel cell vehicle as a driving power source. By using the short-circuit control element, the configuration of the single battery, the assembled battery, and the battery module is greatly simplified as compared with the conventional one, and is provided at a low cost. In addition, a highly reliable battery can be obtained.

  Next, the result of an experiment comparing a battery (Example 1) using the short-circuit control element of the present invention with a battery not using it (Comparative Example 1) will be described.

(Example 1)
In the case of using the short-circuit control element, 20 battery modules were prepared in which 20 1600 mAh can-type lithium ion batteries (4.2 V for charging and 3 V for discharging) were connected in series. A short-circuit control element 4 was attached to each lithium ion battery.

  For the first element 1 of the short-circuit control element 4, tantalum metal (first conductive layer) is used as a valve metal, and anodization is performed at 5.5 V using a 0.5 wt% phosphoric acid electrolytic solution. An oxide film layer was formed on the metal. Further, a carbon paste was applied thereon, and a terminal foil (second conductive layer) connected to the negative electrode side terminal of the battery was connected. A separate test confirmed that the oxide film layer breaks down at 4.5V. It was also confirmed that dielectric breakdown occurred at −0.7 V with reverse voltage.

  Further, as the second element 2, a polyethylene porous film 30 μm (insulating layer) and a titanium foil (fifth conductive layer) that was bent and acted as a leaf spring were laminated, and this was laminated on the first conductive layer 10. These elements were connected by pulling out terminals outside the battery.

  This was followed by 100 cycles at 60V-75V. At this time, the presence or absence of battery abnormality in each module was confirmed.

(Comparative Example 1)
On the other hand, in Comparative Example 1 in which no short-circuit control element was used, 20 battery modules were prepared in which 20 can-type lithium ion batteries (4.2 V during charging and 3 V during discharging) were connected in series.

  The battery module provided with the short-circuit control element 4 and the battery module not using the short-circuit control element were cycled 100 times at 60V to 75V. And the presence or absence of the battery abnormality of each module in this case was confirmed.

(result)
In the case of Example 1, no abnormality was found in the battery module. Of the 400 single cells in total, four were short-circuited by the attached short-circuit control element. There was no leakage or fuming.

  On the other hand, in the direction of Comparative Example 1, abnormality was observed in the two battery modules. Specifically, leakage at one location was confirmed in each of the two battery modules. There was no smoke.

  As can be seen from the comparison results of Example 1 and Comparative Example 1 above, by applying the short-circuit control element of the present invention, even if an abnormality occurs in the unit cell, the short-circuit control element solves the problem, and the battery module has an abnormality. Does not occur. Therefore, there is no leakage. On the other hand, if there is no short circuit control element, it turns out that abnormality will arise in a module.

  Next, the result of an experiment comparing a bipolar battery (Example 2) using the short-circuit control element of the present invention with a bipolar battery (Comparative Example 2) not using it will be described.

(Example 2)
In the case of using the short-circuit control element, the short-circuit control element 4 was installed between each layer of a 1600 mAh bipolar lithium-ion battery (including 20 single cell layers inside, 84V for charging, 60V for discharging).

  In this bipolar battery, a voltage measurement terminal was taken out from the first layer on the positive electrode side, and the voltage of the whole battery was divided by this voltage, thereby calculating the number of normally operating batteries. Twenty bipolar structure batteries were prepared, and their charge and discharge were cycled 100 times from 60V to 75V. At this time, the presence or absence of abnormality of each bipolar structure battery was confirmed.

(Comparative Example 2)
On the other hand, in Comparative Example 2 in which no short-circuit control element is used, 20 lithium-ion batteries with a 1600 mAh bipolar structure (including 20 single cell layers inside, 84V for charging and 60V for discharging) are prepared and charged / discharged. Was cycled 100 times from 60V to 75V. At this time, the presence or absence of abnormality of each bipolar structure battery was confirmed.

(result)
In the direction of Example 2, no abnormality was found in the bipolar battery. In addition, among the 400 unit cell layers in total, six were short-circuited due to the attached short-circuit control element operating. There was no leakage or fuming.

  On the other hand, in the direction of Comparative Example 1, abnormality was observed in the four bipolar batteries. Specifically, leakage at one location was confirmed in each of the four battery modules. In addition, one of the leaks also smoked.

  As can be seen from the comparison results of Example 2 and Comparative Example 2 above, by applying the short-circuit control element of the present invention, even if an abnormality occurs in the single cell layer, the short-circuit control element solves the problem, and the bipolar battery has an abnormality. Does not occur. Therefore, there is no leakage. On the other hand, if there is no short circuit control element, it turns out that abnormality will arise in a bipolar battery.

It is sectional drawing of a 1st element. It is sectional drawing which shows a mode that the short circuit control element which consists of a 1st element was applied to the cell. It is sectional drawing of a 2nd element. It is sectional drawing which shows a mode that the short circuit control element which consists of a 1st element and a 2nd element was applied to the cell. It is sectional drawing which shows the mode of a short circuit control element when abnormality arises in a cell. It is sectional drawing which shows the mode of the short circuit control element following FIG. It is a block diagram of an apparatus to which a short circuit control element is applied. It is a block diagram of an apparatus to which a short circuit control element is applied. It is sectional drawing which shows the internal structure of a bipolar battery. It is a block diagram of an apparatus to which a short circuit control element is applied. It is sectional drawing of a cell.

Explanation of symbols

1 ... 1st element,
2 ... 2nd element,
3, 4 ... short-circuit control element,
5, 6, 7 ... device,
10 ... 1st conductive layer,
11 ... oxide film layer,
12 ... current collecting material layer,
14 ... second conductive layer,
20 ... Third conductive layer,
22 ... Fourth conductive layer,
24 ... fifth conductive layer,
26. Insulating layer,
50 ... single cell,
60 ... Bipolar battery,
60a ... single cell layer,
100: positive terminal,
102: Negative terminal.

Claims (27)

A short-circuit control element that is disposed between a positive electrode terminal and a negative electrode terminal of a unit cell and controls a short circuit of the unit cell,
Having a first element that short-circuits the unit cell by a voltage outside a predetermined range,
A first conductive layer disposed on the positive electrode terminal side and formed of a conductive valve metal;
A second conductive layer provided on the first conductive layer and having conductivity;
An insulating oxide film layer formed on the surface of the first conductive layer on the negative electrode terminal side so as not to contact the first conductive layer and the second conductive layer, and destroyed by a voltage outside a predetermined range;
A short-circuit control element comprising: A third conductive layer disposed on the positive electrode terminal side of the unit cell and having conductivity;
A fourth conductive layer disposed on the negative electrode terminal side of the unit cell and having conductivity;
A fifth conductive layer disposed between the third conductive layer and the fourth conductive layer;
When the fifth conductive layer is disposed between the third conductive layer and the fourth conductive layer so as not to contact at least one of the third conductive layer and the fourth conductive layer, and is heated to a predetermined temperature or higher. An insulating insulating layer that melts;
A second element including
The short-circuit control element according to claim 1, wherein the second element is electrically connected in parallel with the first element.   The short-circuit control element according to claim 1, wherein the valve metal includes at least one of tantalum, niobium, and aluminum.   The short-circuit control element according to claim 1, wherein the oxide film layer has a thickness of 1 nm to 10 nm.   The short-circuit control element according to claim 1, wherein the oxide film layer is formed by anodizing the surface of the valve metal. A current collecting material layer made of an electron conductive or ion conductive current collecting material is disposed between the oxide film layer and the second conductive layer,
The current collecting material is a metal paste, carbon paste, graphite paste, polyaniline, polypyrrole, polyaniline, polypyrrole, polythiophene, or a derivative thereof, β-MnO ₂ , tetrathiafulvalene, tetracyanoquinodimethane, or a mixture thereof. The short-circuit control element according to claim 1, wherein the short-circuit control element is included.   The short-circuit control element according to claim 2, wherein the insulating layer is formed in a film shape.   The short circuit control element according to claim 2, wherein the insulating layer is formed of a thermoplastic resin.   As the thermoplastic resin, at least one resin selected from polyolefin, ethylene-unsaturated carboxylic acid copolymer, styrene block copolymer (SBC), polyamide, polyacryl, polyurethane and polyester is used. The short-circuit control element according to claim 8.   The short-circuit control element according to claim 2, wherein the insulating layer is formed of a porous material.   The short-circuit control element according to claim 2, wherein the insulating layer is formed using a material having a melting point in a range of 60 ° C. to 150 ° C. 4.   The short circuit control according to claim 2, wherein the insulating layer includes a powdery conductive material, a conductive material encapsulated with an insulating material, or a conductive material formed in a thin film shape. element.   The short-circuit control element according to claim 2, wherein the fifth conductive layer has a spring structure in which a force in a direction approaching at least one of the third conductive layer and the fourth conductive layer acts.   The short circuit control according to claim 2, wherein the fifth conductive layer is formed of a shape memory alloy and stores a shape in contact with at least one of the third conductive layer and the fourth conductive layer. element.   The short circuit control element according to claim 1, wherein the short circuit control element is incorporated in a casing of the unit cell.   The short circuit control element according to claim 1, wherein a plurality of the first elements are incorporated.   The short-circuit control element according to claim 16, wherein the plurality of first elements have the oxide film layer destroyed by different voltages.   The short circuit control element according to claim 2, wherein at least one of the first element and the second element is incorporated in plural. In the plurality of first elements, the oxide layer is destroyed by different voltages,
The short circuit control element according to claim 17, wherein the second elements are melted at different temperatures of the insulating layer. Resistors are connected in series,
The short-circuit control element according to claim 1, wherein the short-circuit control element is connected in parallel to the unit cell. A plurality of short-circuit control elements according to any one of claims 1 to 20,
A plurality of unit cell layers connected in parallel for each short-circuit control element;
An exterior housing the short-circuit control element and the unit cell layer;
The bipolar battery is characterized in that the plurality of single battery layers are connected in series.   An assembled battery comprising a plurality of the bipolar batteries according to claim 22 connected.   An assembled battery comprising the short-circuit control elements according to any one of claims 1 to 20 connected in parallel for each unit cell, and a plurality of the unit cells connected.   The number of the single cells is connected in series by an extra number of one or more and 30% or less of the number of series connections than the number of series connections in which a voltage required for operation is obtained. 24. The assembled battery according to 23.   24. The assembled battery according to claim 23, wherein the voltage of at least one of the plurality of single cells is detected by an external voltage detection means.   A battery module comprising a plurality of the assembled batteries according to any one of claims 22 to 25 connected in parallel and / or in series.   A vehicle comprising the bipolar battery according to claim 21, the assembled battery according to any one of claims 22 to 25, or the battery module according to claim 26 as a power source for the vehicle.

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