JP2012182890A - Protective device for secondary battery, secondary battery device, and secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective device for a secondary battery, a secondary battery device, and a secondary battery suitable for a battery pack which can be used continuously with a performance close to that of a battery pack consisting only of normal single batteries while possessing abnormal single batteries.SOLUTION: Breaking parts 12a and 12b which blow when a single battery 2 is in abnormal state are provided in each single battery 2 of a battery pack 1. An inspection switching element 13, and discharge switching elements 14a and 14b which enable connection of a discharge circuit 16 and the single battery 2 are also provided in each single battery 2. A monitoring device 15 monitors each single battery 2 through the inspection switching element 13 and detects an abnormal single battery in which the breaking parts 12a and 12b have blown. A discharge circuit side switching driver 17 turns on the discharge switching elements 14a and 14b connected to the abnormal single battery, and connects the abnormal single battery and the discharge circuit 16.

Description

  The present invention relates to a secondary battery protection device, a secondary battery device, and a secondary battery that are suitable for protecting an assembled battery configured by combining a plurality of secondary batteries.

  Secondary batteries such as nickel metal hydride batteries and lithium ion batteries can be used repeatedly by charging discharged batteries, and are widely used as power sources for mobile devices such as notebook computers and video cameras. ing.

  In many cases, such secondary batteries are used as an assembled battery by combining a plurality of secondary batteries in series or in parallel in order to extract voltage and power necessary for the device. Hereinafter, in the present specification, only one secondary battery is referred to as a single battery with respect to the assembled battery.

  Patent Document 1 describes a battery pack that is a parallel connection set in which a plurality of cells are connected in parallel, and is configured by connecting a plurality of parallel connection sets that do not include a serial connection portion of the cells in series. Has been.

  In such an assembled battery of Patent Document 1, even if one of the cells is an abnormal cell, it is connected in parallel to the normal cell in the parallel connection set. The electrical characteristics such as the open circuit voltage, internal resistance, and discharge capacity of the battery are averaged and uniformed with each other. The voltage difference and the discharge capacity difference are still in progress before the charge / discharge cycle starts. Will always be zero. And, by being averaged, although this parallel connection set has a lower discharge capacity than other parallel connection sets consisting of only normal cells, this decrease is due to the fact that a plurality of single cells including abnormal cells are connected in series. The depth of the overdischarge and overcharge of the abnormal cell can be made shallower than in the conventional case, compared to the decrease of the abnormal cell with respect to the normal cell in the connected series connection set. The decrease in discharge capacity decreases as the number of cells connected in parallel in the parallel connection set increases.

  As a result, the charge / discharge cycle life of the parallel connection set including the abnormal cells can be significantly extended as compared with the case where the conventional serial connection set including a plurality of single cells includes the abnormal cells. Also. Even when abnormal cells are mixed, it is possible to extend the charge / discharge cycle life of the entire assembled battery as compared to the conventional case, and to approach the charge / discharge cycle life of the assembled battery composed only of normal cells.

  On the other hand, conventionally, various protection devices for secondary batteries constituting single cells and assembled batteries have been proposed. For example, in Patent Document 2, one current fuse is connected in series to an assembled battery in which a plurality of single cells are connected in series or in parallel, and an energization opening / closing unit is connected in parallel to a series circuit including the assembled battery and the current fuse. The current switch is closed when the overall voltage Ve of the assembled battery is equal to or higher than the reference voltage by a voltage-sensitive switch, so that the current fuse is blown by a short-circuit current discharged from the assembled battery. A protection device for a secondary battery is described which cuts off the charging / discharging energization circuit and makes it impossible to reuse the assembled battery.

  Patent Document 3 discloses a non-return switch that is interposed in series in a charge / discharge path of an assembled battery in which a plurality of single cells are connected in series, and that physically cuts off the charge / discharge path by its operation, A discharge resistor connected in parallel to the assembled battery whose charge / discharge path is interrupted by the operation of the return switch to form the discharge path of the assembled battery, and when the voltage between the terminals of the entire assembled battery reaches a predetermined voltage Describes a secondary battery protection device that operates a non-return switch to physically cut off a charge / discharge path and form a discharge path of a battery pack via a discharge resistor.

JP-A-8-241705 (published September 17, 1996) JP 2001-352666 A (released on December 21, 2001) JP 2001-126792 A (published on May 11, 2001)

  The assembled battery described in Patent Document 1, that is, a parallel connection set in which a plurality of single cells are connected in parallel, and a plurality of parallel connection sets that do not include a serial connection portion of the single cells are connected in series. Even if an abnormal battery is included, the assembled battery can extend the charge / discharge cycle life of the parallel connection battery including the battery. Even when abnormal cells are mixed, the charge / discharge cycle life of the entire assembled battery can be extended to approach the charge / discharge cycle life of the assembled battery composed only of normal cells.

  However, since the abnormal cell remains connected to the charge / discharge path, when this abnormal cell generates abnormal heat due to thermal runaway etc., heat is also transferred to the surrounding normal cells, and even the normal cells are May become thermally unstable and cause thermal runaway. In order to continue to use the battery safely even when the abnormal cells are mixed, it is desirable to electrically disconnect the abnormal battery from the charge / discharge path and to remove unnecessary capacity stored in the abnormal battery.

  Therefore, in order to prevent the occurrence of such a thermal runaway and use it safely, it is conceivable to provide a secondary battery protection device as described in Patent Documents 2 and 3 in the assembled battery.

  However, the secondary battery protection device described in Patent Documents 2 and 3 physically shuts off the entire assembled battery from its charge / discharge path when one of the cells becomes abnormal. In the first place, it does not even have a technical idea of disconnecting (electrically disconnecting) only the abnormal unit cell from the charge / discharge path.

  Therefore, it cannot be used for the above-mentioned assembled battery that can continue to be used with performance close to the assembled battery composed of only normal cells while possessing abnormal cells.

  The present invention has been made in view of the above problems, and its purpose is to provide an assembled battery that can be used with performance close to that of an assembled battery that is composed of only normal cells while possessing abnormal cells. And a secondary battery device including the secondary battery protection device and an assembled battery.

  In order to solve the above-described problems, the secondary battery protection device of the present invention is a battery pack composed of one parallel connection set in which a plurality of single batteries as a single secondary battery are connected in parallel, or the above A protection device for a secondary battery of an assembled battery configured by connecting a plurality of parallel connection sets in series, provided for each unit cell, when the unit cell is in an abnormal state, the electrical energy in the abnormal unit cell The electrode plate part that has accumulated the charge and discharge path can be connected to the electrode plate part of each cell and the blocking part that non-reversibly cuts off the connection between the electrode plate part and the electrode plate part. A discharge circuit that forms a discharge path of the unit, a monitoring unit that monitors each unit cell and detects an abnormal unit cell in which the connection between the electrode plate unit and the charge / discharge path is blocked by the blocking unit, and the monitoring Connect both electrodes of the electrode plate of the abnormal cell detected at the It is characterized in that it comprises a discharge circuit connector for.

  The said structure WHEREIN: Even if the said interruption | blocking part is provided in the cell exterior, the connection part which connects the said discharge circuit connection part to the said interruption | blocking part and the said electrode plate part may be provided in the inside of a cell. .

  In the above configuration, the monitoring unit constantly monitors each unit cell of the assembled battery. Under such circumstances, when a certain cell is in an abnormal state and the temperature rises, the interrupting portion provided for each cell is a charge / discharge path on both electrode sides of the electrode plate portion of the unit cell that has become abnormal. The connection with is not interrupted. The monitoring unit can always detect an abnormal unit cell that has been blocked from the charge / discharge path by such a blocking unit by constantly monitoring. The discharge circuit connection unit connects the electrode plate portion of the abnormal cell detected by the monitoring unit to the discharge circuit, and removes unnecessary capacity (unnecessary electrical energy) accumulated in the electrode plate portion of the abnormal cell. .

  Thereby, it is possible to electrically disconnect only the abnormal battery cell that is in an abnormal state in the assembled battery from the charge / discharge path, and to quickly remove the unnecessary capacity accumulated in the abnormal battery cell. .

  According to such a method for dealing with abnormal cells, the remaining normal cells of the assembled battery remain connected to the charge / discharge path, and the abnormal cells do not generate heat abnormally. The assembled battery can continue to be used with the remaining normal cells.

  In other words, the secondary battery protection device of the present invention is applicable to an assembled battery that can be used with performance close to that of an assembled battery that is composed of only normal cells while having an abnormal cell. is there.

  Thereby, by using the protection device for a secondary battery of the present invention, an assembled battery that can continue to be used with performance close to the assembled battery composed of only normal cells while holding the abnormal cells, It is possible to continue to use it safely without the danger of thermal runaway.

  In the protection device for a secondary battery of the present invention, the blocking portion is a PTC element that is disposed on both electrodes of the electrode plate portion of the unit cell and is blown when the unit cell becomes abnormal and the temperature rises. it can.

  By using a PTC element that melts at a set temperature, the above-described blocking part can be easily realized.

  In the protection device for a secondary battery of the present invention, the monitoring unit includes an inspection switching element provided for each unit cell for detecting a signal flowing from each unit cell to a charge / discharge path, and each of the inspection switching elements. And a monitoring circuit to which a signal detected by each inspection switching element is input, and the inspection switching element is connected to a side farther from the blocking part when viewed from the electrode plate part. The monitoring circuit can be configured to detect an abnormal cell based on a signal input from each inspection switching element.

  A switching element for inspection, which is provided for each unit cell and detects a signal flowing from each unit cell to the charge / discharge path, is connected to a side farther from the blocking unit when viewed from the electrode plate unit. Therefore, when the electrode plate part and the charge / discharge path are interrupted by the interrupting part and no current flows through the charge / discharge path, this can be detected from the signal flowing through the charge / discharge path. The monitoring circuit sequentially samples signals flowing through the charge / discharge paths by driving each inspection switching element, and detects an abnormal single cell based on the sampled signals. By setting it as such a structure, the monitoring part which always monitors each above-mentioned single cell is easily realizable.

  In the protection device for a secondary battery according to the present invention, the discharge circuit connecting portion is selectively provided with each of the discharge circuits on the side closer to the electrode plate portion than the blocking portion. A discharge switching element to be connected to each other, and a driver for driving each of the discharge switching elements, wherein the abnormal single cell is driven by driving the discharge switching element connected to the abnormal single cell detected by the monitoring unit A driver circuit for connecting the electrode plate portion and the discharge circuit can be used.

  The discharge switching element provided for each unit cell selectively connects both electrodes of the electrode plate portion to the discharge circuit closer to the electrode plate portion than the blocking portion. That is, the electrode plate part interrupted from the charge / discharge path by the interrupting part can be connected to the discharge circuit. A driver circuit for driving the discharge switching element drives the discharge switching element connected to the abnormal cell detected by the monitoring unit to connect the electrode plate of the abnormal cell and the discharge circuit. Thereby, unnecessary capacity remaining in the electrode plate portion of the abnormal unit cell is removed. By setting it as such a structure, the discharge circuit connection part which connects an above-mentioned abnormal cell to a discharge circuit is easily realizable.

  The secondary battery device of the present invention is an assembled battery composed of the above-described protection device for a secondary battery of the present invention and a single parallel connection set in which a plurality of single cells as a single secondary battery are connected in parallel, Or it has the assembled battery comprised by connecting the said multiple parallel connection group in series, It is characterized by the above-mentioned.

  As already described as the explanation of the protection device for the secondary battery, the secondary battery device of the present invention has the abnormal single cell, but safely and without any danger of thermal runaway, etc. It becomes possible to continue using it with the performance close to the assembled battery comprised only.

  The secondary battery of the present invention has an electrode plate portion in which electric energy is stored in an electrode case, and connects the electrode plate portion connected to the positive electrode and the negative electrode of the electrode plate portion to a charge / discharge path. In the secondary battery in which the external terminal is provided in the battery case, when the secondary battery becomes abnormal in the battery case, the connection between the electrode plate part and the external terminal is connected to the electrode plate part. The battery case is characterized in that a blocking portion for blocking non-returning is provided on both electrode sides, and the battery case has a second external terminal connected to the positive electrode and the negative electrode of the electrode plate portion.

  As described above, in the protection device for a secondary battery according to the present invention, the blocking unit may be provided outside the unit cell that is a single secondary battery, or may be provided inside the battery. When the interruption | blocking part is provided in the cell, the connection part which connects an electrode plate part to a discharge circuit connection part will also be provided in a cell.

  The secondary battery of the present invention is a configuration in which a second external terminal connected to the positive electrode and the negative electrode of the electrode plate portion is provided in the battery case in the configuration in which the blocking portion is provided in the battery case. Therefore, it becomes possible to connect the electrode plate portion to the discharge circuit connection portion by using the second external terminal, and the secondary battery protection device of the present invention can be applied.

  The protection device for a secondary battery according to the present invention reduces the risk of thermal runaway, etc., from an assembled battery that can be used with performance close to an assembled battery that is composed of only normal cells while possessing abnormal cells. The secondary battery device of the present invention having such a secondary battery protection device can be safely used without being accompanied by such a risk as thermal runaway while holding an abnormal cell. Therefore, it is possible to continue to use it safely and with performance close to an assembled battery composed of only normal cells.

1 is a circuit block diagram of a secondary battery protection device and a secondary battery device according to an embodiment of the present invention. It is explanatory drawing which shows the example of the assembled battery with which the said protection apparatus for secondary batteries protects and the said secondary battery apparatus is provided. It is explanatory drawing which shows another example of the assembled battery which the said secondary battery protective device protects and the said secondary battery apparatus is equipped with. It is a flowchart which shows operation | movement of the said secondary battery protective device. A secondary battery protection device in which the secondary battery protection device is configured to share a monitoring device, a discharge circuit side switching driver, and a discharge circuit in a plurality of parallel units. It is a circuit block diagram of a secondary battery device. In the secondary battery device provided with the secondary battery protection device, it is a diagram for explaining the loss capacity when one unit cell becomes abnormal. It is drawing explaining the loss capacity when one unit cell becomes abnormal in the secondary battery device provided with the protection device for secondary batteries of a reference example. It is a schematic diagram which shows the example of a connection of the cell and discharge circuit in the said protection apparatus for secondary batteries. It is a schematic diagram which shows the example of a connection of the cell and discharge circuit in the protection apparatus for secondary batteries which is other embodiment of this invention. It is a circuit block diagram of the protection apparatus for secondary batteries which is the other form of implementation of this invention, and a secondary battery apparatus.

[Embodiment 1]
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a circuit block diagram of a secondary battery protection device 10 and a secondary battery device 100 according to an embodiment of the present invention. The secondary battery protection device 10 includes a battery pack 1 configured by connecting a plurality of parallel units (parallel connection sets) 3 in which a plurality of battery cells 2, each of which is a single secondary battery, are connected in parallel. It is a suitable secondary battery protection device.

  FIG. 1 shows a secondary battery protection device 10 provided in one parallel unit 3 constituting the assembled battery 1. Actually, the assembled battery 1 includes, for example, a plurality of parallel units 3 directly connected as shown in FIG. 2 or a parallel structure in which a plurality of parallel units 3 are directly connected as shown in FIG. A plurality of unit serial bodies 4 may be connected in parallel.

  In the assembled battery 1, the number of cells 2 connected in parallel in the parallel unit 3, the number of parallel units 3 connected in series, and the number of parallel unit series bodies 4 connected in parallel are all arbitrary. It is determined based on the voltage and power required for the battery pack 1 according to the equipment to be mounted. The assembled battery 1 may be configured to include only one parallel unit 3.

  The protection apparatus 20 for secondary batteries is provided with respect to each parallel unit 3 which comprises such an assembled battery 1, respectively. In addition, the secondary battery device 100 according to the present embodiment includes the secondary battery protection device 10 and the assembled battery 1.

  Returning to FIG. 1 again, the configuration of the secondary battery protection device 10 will be described. As shown in FIG. 1, the secondary battery protection device 10 includes a blocking unit 12 a and 12 b, an inspection switching element 13, a monitoring device (monitoring circuit) 15, a discharge switching element 14 a and 14 b, and a discharge circuit. 16 and a discharge circuit side switching driver 17.

  Among these, the blocking units 12 a and 12 b, the inspection switching element 13, and the discharge switching elements 14 a and 14 b are provided for each unit cell 2 included in the parallel unit 3.

  The pair of blocking portions 12a and 12b provided in each unit cell 2 connects the unit cell 2 and the charging / discharging path 11 (shown in bold lines in the figure) when each unit cell 2 is in an abnormal state. Is cut off in a non-returning manner on both polar sides of the unit cell 2.

  The blocking portions 12a and 12b can be configured by, for example, PTC elements disposed on the positive electrode side and the negative electrode side of the unit cell 2, respectively. The PTC elements that make a pair with the unit cell 2 sandwiched are blown when an abnormality occurs in the unit cell 2 and the temperature of the unit cell rises abnormally. The PTC element is an element whose resistance value increases as the temperature rises and current does not easily flow. Here, an element having a low melting point is used, and when the melting point is exceeded, the PTC element melts and becomes non-conductive.

  In addition, the interruption | blocking part 12a * 12b does not have influence on the electricity supply to the charging / discharging path | route 11 at the time of normal, and does not reset the electrical connection of the charging / discharging path | route 11 and the abnormal cell 2 at the time of abnormality of the cell 2. Anything that can be shut off is acceptable.

  Further, in the present embodiment, the blocking portions 12a and 12b are configured to be provided outside the unit cell 2, but as will be described later, inside the unit cell 2, that is, inside the cell case of the unit cell 2. It can also be provided. In short, the interruption | blocking part 12a * 12b interrupts | blocks the connection of the electrode plate part which accumulated the electrical energy of the cell 2 which became an abnormal state, and the charging / discharging path | route 11. FIG.

  The inspection switching element 13 connected to the charge / discharge path 11 of each unit cell 2 detects a signal flowing from the unit cell 2 to the charge / discharge path 11. The bases (gates) of the inspection switching elements 13 are independently connected to the monitoring device 15, and each unit cell 2 can be selectively connected to the monitoring device 15.

  Such a switching element for inspection 13 is arranged on the side farther from the blocking portion 12a when viewed from the single cell 2. As the inspection switching element 13, various switching elements such as a bipolar transistor and a field effect transistor can be used.

  The monitoring device 15 drives each inspection switching element 13 independently, and detects an abnormal cell based on a signal detected by each inspection switching element 13. The monitoring device 15 repeatedly turns on / off each of the inspection switching elements 13 in a matrix, and detects the unit cell 2 that is in an abnormal state based on a signal from each of the inspection switching elements 13 that is input when the monitoring switching element 13 is on. .

  Since the unit cell 2 (in detail, its electrode plate portion) in an abnormal state is blocked from the charge / discharge path 11 by the blocking units 12a and 12b, the inspection corresponding to the blocked unit cell 2 is performed. The output signal from the switching element 13 is different from other normal cells 2 connected to the charge / discharge path 11. The monitoring device 15 detects such a difference. Information on the unit cell 2 in an abnormal state detected by the monitoring device 15 is output to the discharge circuit side switching driver 17 described later.

  Each unit cell 2 is monitored by the inspection switching element 13 provided in each unit cell and the monitoring device 15, and the charging / discharging path 11 is blocked by the blocking units 12a and 12b. A monitoring unit for detecting the unit cell is configured. The monitoring unit constantly monitors each single battery 2. In FIG. 1, the inspection switching element 13 is arranged on the positive electrode side of the unit cell 2 via the blocking part 12 a, but the inspection switching element 13 is connected to the negative electrode of the unit cell 2 via the blocking part 12 b. It can also be provided on the side.

  A pair of discharge switching elements 14a and 14b provided in each unit cell 2 has a base (gate) independently connected to the discharge circuit side switching driver 17 for each pair, and the unit cell 2 is selected. Thus, it is possible to connect to the discharge circuit 16. The discharge circuit side switching driver 17 turns on the discharge switching elements 14a and 14b provided on both sides of the unit cell 2 in which the abnormality has occurred. Electrode plate part) is connected to the discharge circuit 16.

  Such discharge switching elements 14a and 14b are connected to the positive electrode side and the negative electrode side of the unit cell 2 and closer to the unit cell 2 than the blocking portions 12a and 12b. By connecting the discharge switching elements 14a and 14b closer to the unit cell 2 than the blocking units 12a and 12b, the unit cell 2 in which the charge / discharge path 11 is blocked by the blocking units 12a and 12b is discharged. The circuit 16 can be connected.

  In addition, since the interruption | blocking part 12a * 12b can be provided in the inside of the cell 2 as mentioned above, in such a case, switching element 14a * 14b for discharge is an electrode plate rather than interruption | blocking part 12a * 12b. It will be connected to the side close to the part.

  As the discharge switching elements 14a and 14b, various switching elements such as a bipolar transistor and a field effect transistor can be used in the same manner as the inspection switching element 13.

  On / off driving of the discharge switching elements 14a and 14b provided in each unit cell 2 is performed by a discharge circuit side switching driver (driver circuit) 17. As described above, the discharge circuit side switching driver 17 is input with the information of the unit cell 2 in an abnormal state detected by the monitoring device 15. The discharge circuit side switching driver 17 turns on the discharge switching elements 14a and 14b connected to the unit cell 2 in an abnormal state based on the information notified from the monitoring device 15. Thereby, the unit cell 2 in an abnormal state is connected to the discharge circuit 16.

  A pair of discharge switching elements 14a and 14b provided in each unit cell and a discharge circuit side switching driver 17 connect the unit cell 2 in an abnormal state detected by the monitoring unit to the discharge circuit 16. A discharge circuit connecting portion is configured.

  The discharge circuit 16 is selectively connected to each unit cell 2 to form a discharge path for the connected unit cell 2, and includes a discharge resistor or the like and is connected to the ground potential.

  Next, the operation of the secondary battery protection device 20 will be described with reference to the flowchart of FIG.

  The monitoring device 15 in the secondary battery protection device 20 constantly monitors the output signal from the inspection switching element 13 provided in each unit cell 2 during charging and discharging of the assembled battery 1. The state of each unit cell 2 is monitored (S1).

  During such monitoring, one of the plurality of unit cells 2 (which may be a plurality of unit cells) 2 becomes abnormal and its temperature rises (S2). When the blocking sections 12a and 12b arranged in the are cut off, the monitoring device 15 detects the blowout from the output signal from the inspection switching element 13 (S3, S4).

  The monitoring device 15 notifies the discharge circuit side switching driver 17 of the information (position information) of the unit cell 2 that has detected the fusing and is in an abnormal state (S5). Upon receiving the notification from the monitoring device 15, the discharge circuit side switching driver 17 turns on and opens the discharge switching elements 14a and 14b connected to the unit cell 2 that has become abnormal (S6).

  When the discharge switching elements 14a and 14b are opened and the unit cell 2 in an abnormal state is connected to the discharge circuit 16, the unnecessary capacity stored in the unit cell 2 in the abnormal state is increased. Then, it is discharged and removed through the discharge circuit 16 (S7). As a result, the unit cell 2 in an abnormal state is thermally stabilized (S8).

  As described above, in the secondary battery protection device 10, if there is an abnormal unit cell 2 whose temperature has started to rise among the plurality of unit cells constituting the assembled battery 1, the breakers 12 a and 12 b are blown out. When the temperature is exceeded, the battery is disconnected from the charge / discharge path 11 and the monitoring device 15 quickly detects the disconnection, notifies the discharge circuit side switching driver 17, and connects to the discharge circuit 16 to discharge.

  According to such a method for dealing with the abnormal cell 2, the remaining normal cells 2 of the assembled battery 1 remain connected to the charge / discharge path 11 and the abnormal cell 2 generates abnormal heat. Therefore, the assembled battery 1 can continue to be used with the remaining normal cells 2.

  Such a secondary battery protection device 10 is not limited to the configuration provided for each parallel unit 3 as shown in FIG. 1, and for example, in a plurality of parallel units 3 as shown in FIG. 5, the monitoring device 15 ′. The discharge circuit side switching driver 17 ′ and the discharge circuit 16 ′ may be shared.

  Next, the superiority of the secondary battery protection device 10 of this embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 shows that the secondary battery protection device 10 is provided in each parallel unit 3 of the assembled battery 1 constituted by connecting three parallel units 3 in which five single cells 2 are connected in parallel. In the secondary battery apparatus 101 of an Example, it is drawing explaining the loss capacity when one cell becomes abnormal.

  On the other hand, FIG. 7 similarly shows that each of the parallel units 3 of the assembled battery 1 constituted by connecting three parallel units 3 connected in parallel with five unit cells 2 in series is disclosed in Patent Documents 2 and 3 of the related art. It is drawing explaining the loss capacity when one unit cell becomes abnormal in the secondary battery device 301 of the reference example provided with the secondary battery protection device 300 of the reference example obtained. The secondary battery protection device 300 of the reference example shuts off the parallel unit 3 including the single battery 2A in units when the single battery 2 is in an abnormal state.

  6 and 7, for the sake of convenience, the secondary battery protection device 10 or the secondary battery protection device 300 is described as being provided only in the first-stage parallel unit 3. Protective device 10 or secondary battery protective device 300 is provided in each parallel unit 3.

  Assuming that the current amount per hour of the single battery 2 is 1 Ah, the total capacity of the two secondary battery devices 101 and the secondary battery device 301 when all the single cells 2 are functioning normally is 1 Ah × 15 Ah for 15 pieces.

  In such two secondary battery devices 101 and the secondary battery device 301, the capacity loss when an abnormality occurs in one unit cell 2 is calculated as follows.

  In the secondary battery device 101 of the embodiment, since only one single cell 2A included in one parallel unit 3 in the three parallel units 3 is disconnected, the power loss is 1 Ah for only one single cell. That is, even after one unit cell 2 becomes abnormal, it can be used normally at 14 Ah.

  On the other hand, in the secondary battery device 301 of the reference example, since the parallel unit 3 including the abnormal unit cell 2A is disconnected, the remaining parallel units 3 are two. The power loss is also 5 Ah for one parallel unit, that is, for 5 cells. Therefore, only one unit cell 2 becomes abnormal, and the power is reduced to 10 Ah.

  In a device driven at 15 Ah, if it is 14 Ah, it can be driven without any trouble, but it can be easily assumed that it becomes impossible to drive when the price is reduced to 10 Ah.

As described above, according to the secondary battery protection device 10, only the unit cell 2 that is in an abnormal state in the assembled battery 1 is electrically disconnected from the charging / discharging path 11, and this abnormal unit cell is used. The unnecessary capacity stored in 2 can be quickly removed. According to such a method for dealing with the abnormal cell 2, the remaining normal cells 2 of the assembled battery 1 remain connected to the charge / discharge path 11 and the abnormal cell 2 generates abnormal heat. The assembled battery 1 is the remaining normal unit cell 2 and can be used safely without any danger of thermal runaway.
[Embodiment 2]
Hereinafter, other embodiments of the present invention will be described in detail with reference to FIGS. For convenience of explanation, members having the same functions as those used in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As described above, in the secondary battery protection device 10, the blocking portions 12 a and 12 b can be provided inside the unit cell 2, that is, inside the battery case of the unit cell 2. This embodiment demonstrates the structure by which interruption | blocking part 12a * 12b is provided in the inside of a battery.

  FIG. 8 is a schematic diagram showing an example of connection between the unit cell 2 and the discharge circuit 16 when the blocking portions 12a and 12b described in the first embodiment are outside the battery. The unit cell 2 has an electrode plate portion 22 in which electric energy is stored inside the battery case 21, and the positive electrode and the negative electrode are provided in the battery case 21 via lead tabs 23 and 23 made of a conductor. The positive and negative external terminals (first external terminals) 24a and 24b are connected.

  The blocking portions 12a and 12b are provided outside the unit cell 2. Between the blocking units 12a and 12b and the positive and negative external terminals 24a and 24b of the unit cell 2, discharge switching elements 14a and 14b are provided. It is connected.

  In this case, when the unit cell 2 reaches an abnormal temperature and the blocking portions 12a and 12b are melted, the discharge switching elements 14a and 14b are turned on, and the positive and negative external terminals 24a and 24b of the unit cell 2 are turned on. 24b and the discharge circuit 16 are connected.

  On the other hand, FIG. 9 shows a connection example between the unit cell 20 and the discharge circuit 16 when the blocking portions 12a and 12b are inside the battery. In the unit cell 20, blocking portions 12 a and 12 b are provided inside the battery case 21. In detail, between the extraction tabs 23 and 23 connected to the positive electrode and the negative electrode of the electrode plate portion 22 and the external terminals 24 a and 24 b of the positive electrode and the negative electrode provided on the battery case 21, the blocking portions 12 a and 12 b are provided. Is provided.

  The battery case 21 has positive and negative electrodes connected to the lead-out tabs 23 and 23 separately from the positive and negative external terminals 24a and 24b connected to the charge / discharge path 11 (see FIG. 10). Second external terminals 25a and 25b are provided. The discharging switching elements 14a and 14b are connected to the positive and negative second external terminals 25a and 25b, respectively.

  In this case, when the unit cell 20 reaches an abnormal temperature and the cutoff portions 12a and 12b are melted, the discharge switching elements 14a and 14b are turned on, and the electrode plate portion 22 and the discharge circuit 16 are connected. .

  8 and 9, the positive and negative external terminals (first external terminals) 24a and 24b, the positive and negative external terminals 25a and 25b, and the battery case 22 The structure of the provided insulator etc. is omitted.

  Further, in FIG. 9, the second external terminals 25 a and 25 b of the positive electrode and the negative electrode are described as being provided on the peripheral surface (side surface) of the battery, but FIG. 9 is a schematic diagram to the last, It does not specify the formation position. In practice, it is preferable to provide the positive electrode and the negative electrode on the same surface as the surfaces on which the external terminals (first external terminals) 24a and 24b are provided.

  FIG. 10 shows a secondary battery device having a structure in which, instead of the unit cell 2, such a blocking unit 12 a, 12 b is provided inside the cell, and the unit cell 20 provided with the second external terminals 25 a, 25 b is provided. 2 is a circuit block diagram of 200. FIG.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

1 assembled battery 2 single battery (secondary battery)
3 Parallel units (parallel connection set)
4 Parallel Unit Series 10 Secondary Battery Protection Device 11 Charge / Discharge Path 12a / 12b Blocking Section 13 Inspection Switching Element 14a / 14b Discharge Switching Element 15.15 ′ Monitoring Device (Monitoring Circuit)
16.16 'discharge circuit 17.17' discharge circuit side switching driver (driver circuit)
20 Single battery (secondary battery)
21 Battery case 22 Electrode plate part 24 a / 24b External terminal (first external terminal)
25 a and 25 b Second external terminal 100 Secondary battery device 101 Secondary battery device 200 Secondary battery device

Claims (8)

An assembled battery constituted by one parallel connection set in which a plurality of single cells as a single secondary battery are connected in parallel, or a secondary battery of an assembled battery constituted by connecting a plurality of the parallel connection sets in series Protective device for
Provided for each unit cell, when the unit cell is in an abnormal state, the connection between the electrode plate part storing the electrical energy in the abnormal unit cell and the charge / discharge path is cut off non-returnably on both electrode sides of the electrode plate unit And
A discharge circuit that can be connected to both electrodes of the electrode plate portion of each unit cell and forms a discharge path of the connected electrode plate portion;
A monitoring unit that monitors each unit cell and detects an abnormal unit cell in which the connection between the electrode plate unit and the charge / discharge path is blocked by the blocking unit,
A protection device for a secondary battery, comprising: a discharge circuit connection portion for connecting both electrodes of the electrode plate portion of the abnormal cell detected by the monitoring portion to the discharge circuit.   2. The secondary device according to claim 1, wherein the blocking portion is a PTC element that is disposed at both electrodes of the electrode plate portion of the single cell and blows when the single cell becomes abnormal and the temperature rises. Battery protection device. The monitoring unit
A switching element for inspection, which is provided for each unit cell and detects a signal flowing from each unit cell to the charge / discharge path;
A monitoring circuit that drives each of the inspection switching elements and receives a signal detected by each of the inspection switching elements;
The inspection switching element is connected to a side farther from the blocking portion when viewed from the electrode plate portion,
The secondary battery protection device according to claim 1, wherein the monitoring circuit detects an abnormal cell based on a signal input from each inspection switching element. The discharge circuit connection part is
Discharging switching element that is provided for each unit cell and selectively connects the electrode plate part to the discharge circuit on the side closer to the electrode plate part than the blocking part;
A driver for driving each of the discharge switching elements, wherein the discharge switching element connected to the abnormal cell detected by the monitoring unit is driven to drive the electrode plate of the abnormal cell and the discharge circuit; 4. The secondary battery protection device according to claim 1, further comprising: a driver circuit that connects the two.   The secondary battery protection device according to claim 1, wherein the blocking unit is provided outside the unit cell.   The secondary part according to any one of claims 1 to 4, wherein a connection part for connecting the discharge circuit connection part to the blocking part and the electrode plate part is provided inside the unit cell. Battery protection device. An assembled battery constituted by one parallel connection set in which a plurality of single cells which are single secondary batteries are connected in parallel, or an assembled battery constituted by connecting a plurality of the above parallel connection sets in series;
A secondary battery device comprising the secondary battery protection device according to any one of claims 1 to 6. A first external terminal for connecting the electrode plate part to the charge / discharge path, which is connected to the positive electrode and the negative electrode of the electrode plate part, has an electrode plate part storing electric energy in the electrode case, and is a battery. In the secondary battery provided in the case,
In the battery case, when the secondary battery is in an abnormal state, there is provided a blocking portion for blocking non-returning connection between the electrode plate portion and the external terminal on both electrode sides of the electrode plate portion,
The battery case further includes a second external terminal connected to the positive electrode and the negative electrode of the electrode plate portion in the battery case.

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