JP2018026308A - Control system of battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a number of smoke generation of an electric cell to be estimated higher than the conventional one.SOLUTION: A control part 12 comprises: a smoke exhaust temperature integration part 82; a smoke generation number estimation prat 86; and a commanding part 88. The smoke exhaust temperature integration part 82 starts an integration of a smoke exhaust temperature Tcounting from an excess point of a threshold value Kth when it is determined that a differential value dT/dt of the smoke exhaust temperature exceeds a predetermined threshold value Kth, and at least any one of a voltage, resistance, and a capacity of a battery pack 10 has an abnormality on the bass of voltages V1, V2, and V3 of the battery pack 10 and a current I. The smoke generation number estimation prat 86 estimates a smoke generation number N of an electric cell 20 in the battery pack 10 on the basis of an integrated value ∫Tafter a predetermined standby time Tfrom the excess point of the threshold value Kth. The commanding part 88 selects and commands a predetermined security control item from a plurality of security control items on the basis of the smoke generation number N to be estimated.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a battery pack control system.

  A battery module that is a DC power supply is mounted on a vehicle that uses a rotating electrical machine as a drive source, such as an electric vehicle or a hybrid vehicle. For the purpose of diversifying the layout, the battery module may be divided (divided) into a plurality of battery packs.

  In the battery pack, a plurality of single cells (battery cells) are connected in parallel. If these multiple cells are connected in series, the continuity of the entire battery pack will be interrupted if one of them is damaged, but by connecting in parallel, power can be taken out from the battery pack even if several batteries are damaged. There are benefits. Therefore, in a battery pack in which a plurality of single cells are connected in parallel, in addition to suppressing the breakage of each single cell, the deterioration status of each single cell including breakage, and safety control such as power management at the time of breakage (failure) Safe) is executed.

  If the unit cell is overheated due to an internal short circuit or the like, the electrolyte may become gas due to decomposition or vaporization, and the internal pressure may increase, leading to damage. Therefore, for example, in Patent Document 1, the internal pressure of each single cell is calculated (estimated) from the temperature of the terminal plate connected to the single cell and the remaining capacity of each single cell, and the internal pressure damage obtained from this internal pressure is integrated, The deterioration state of the unit cell is estimated based on the integrated value.

  Further, the cell is provided with a gas discharge valve. When the internal pressure reaches a predetermined high pressure, the gas discharge valve is opened and the gas in the cell is discharged. For example, in Patent Document 2, a plurality of items such as warning output, vehicle stop, binder spray, and the like are prepared as safety control (fail safe) accompanying gas discharge, and safety control is appropriately performed according to the concentration of discharged gas. Selected.

Japanese Patent Laying-Open No. 2015-141790 JP 2014-512004 A

  By the way, in patent document 2, the state of smoke generation at that time is detected from the exhausted gas concentration, and what kind of security control is performed is selected. However, when considering the capacity of the battery pack, it may be preferable to select the safety control according to the number of single cells deteriorated due to smoke generation. For example, when the number of smoke generation is relatively small, the input / output power limit (Win / Wout) is used. When the number of smoke generation is relatively large, it is unlikely that sufficient power will be obtained from the battery pack. Operation such as letting it be considered.

  When measured values such as gas concentration and gas temperature in the battery module are used, there is a possibility that the estimated number of smoke is different depending on whether a plurality of smokes are emitted at the same time or when smoke is emitted with a time difference. For example, if the first cell emits smoke and the next cell emits smoke after the gas passes through the gas concentration sensor, the gas concentration is limited to one and the number of smoke is estimated to be one. There is a risk of being.

  Then, an object of this invention is to provide the vehicle-mounted battery unit which enables estimation of the number of fumes of a single cell with higher precision than before.

  The present invention relates to a battery pack control system in which a plurality of single cells are connected in parallel. The system includes a smoke temperature sensor provided in a smoke passage through which a gas discharged from the unit cell is provided and a voltage sensor that measures a voltage of the battery pack. A current sensor that measures a current; and a control unit that performs security control on the battery pack according to a measured value of the smoke temperature sensor, the voltage sensor, and the current sensor. The control unit determines that the differential value of the flue gas temperature exceeds a predetermined threshold, and at least one of the voltage, resistance, and capacity of the battery pack is abnormal based on the voltage and current of the battery pack. When determined, based on an integrated value of the flue gas temperature starting from the time when the threshold is exceeded, and an integrated value of the flue gas temperature after a predetermined waiting time from the time when the threshold is exceeded And a command for selecting and commanding a predetermined safety control item from a plurality of safety control items based on the estimated number of smoke. A section.

  According to the present invention, the number of smoked cells is estimated based on the integrated value (integrated value) of the smoke temperature. Even if a plurality of single cells emit smoke sequentially with a time difference, the integrated value is close to the value at the time of simultaneous smoke generation if it is within the integration period. In addition, in the present invention, when integrating the smoke generation temperature, a double check between the presence / absence of a temperature abnormality in the smoke generation path and the presence / absence of an abnormality in the electric system reliably detects the occurrence of smoke generation, that is, the integrated calculation point. Thereby, it is possible to suppress temperature integration from being started before smoke generation.

It is a figure which illustrates an AA section and control system of a battery pack concerning this embodiment. It is a perspective view which illustrates the battery pack concerning this embodiment. It is a disassembled perspective view which illustrates the battery pack which concerns on this embodiment. It is a figure which illustrates the hardware constitutions of a control part. It is a figure which illustrates the function part of a control part. It is a figure which illustrates the temperature change at the time of the smoke of a single cell (simultaneous smoke). It is a figure which illustrates the temperature change at the time of the smoking of a cell (time difference smoking). It is a flowchart which illustrates the security control flow which concerns on this embodiment.

  FIG. 1 illustrates a control system for the battery pack 10 according to the present embodiment. The control system includes a control unit 12, voltage sensors 14A, 14B, 14C, a current sensor 16, and a smoke emission temperature sensor 18. The battery pack 10 and its control system are mounted on a vehicle that uses a rotating electrical machine as a drive source, such as an electric vehicle or a hybrid vehicle.

  FIG. 2 illustrates an external appearance of the battery pack 10, and FIG. 3 illustrates an exploded perspective view of a main part configuration. In the following description, terms representing directions such as up / down / left / right, side, front, back, and the like indicate directions in the drawings used for the description unless otherwise specified, and the battery pack 10 is actually installed. It is not related to the direction. The battery pack 10 includes a unit cell 20, a battery holder 22, a negative electrode bus bar 24, a smoke exhaust chamber cover 26, a side cover 28, a positive electrode bus bar 30, and an upper cover 32.

  The battery pack 10 includes a plurality of cells 20 connected in parallel. The unit cell 20 has a substantially cylindrical shape, and a positive electrode is provided at one end of the cylinder and a negative electrode is provided at the other end. The unit cell 20 has a positive electrode end disposed on the upper side and a negative electrode end disposed on the lower side. The cell 20 can be a secondary battery such as a nickel metal hydride battery or a lithium ion battery.

  As shown in the partial enlarged view (A) of FIG. 1, a gas discharge valve 34 is formed at the negative electrode end of the unit cell 20. For example, a thin part may be formed in a part of the negative electrode terminal of the hollow cylindrical case 42 containing the positive electrode sheet 36, the negative electrode sheet 38, and the separator 40 sandwiched between them, and this may be used as the gas discharge valve 34. . When the case internal pressure increases, the discharge valve 34 is opened (the thin portion is broken) prior to other parts of the case 42, and the gas inside the case 42 is discharged from here. The discharged gas flows into the smoke exhaust chamber 46 through the opening 44 of the negative electrode bus bar 24.

  2 and 3, the side cover 28 is disposed so as to surround the side periphery of the battery holder 22 that holds the unit cells 20. The side cover 28 is fixed to the battery holder 22 with its lower end in contact with the upper surface of the battery holder 22.

  Further, the side cover 28 has a ceiling plate 48 in the vicinity of the upper end thereof. The ceiling plate 48 is provided with holding openings 50 respectively corresponding to the arranged cells 20. From the holding opening 50, the positive electrode of each unit cell 20 is exposed.

  Above the ceiling plate 48, a positive electrode bus bar 30 that connects the positive electrodes of the unit cells 20 is disposed. The upper side of the positive electrode bus bar 30 is covered with an insulating upper cover 32.

  The positive bus bar 30 has a plurality of (for example, three) bus bar segments connected by an insulating material such as a resin mold. As will be described later, the negative electrode bus bar 24 is also divided into a plurality of bus bar segments in the same manner as the positive electrode bus bar 30, so that the segment (battery segment) in which the plurality of single cells 20 are connected in parallel is the number of bus bar segments (for example, 3).

  The battery holder 22 has a substantially plate shape, and the accommodation holes 52 are two-dimensionally arranged on the plate plane. The accommodation hole 52 penetrates the battery holder 22 in the plate thickness direction. Each accommodation hole 52 has a cylindrical shape that fits with the columnar shape of the unit cell 20. Each unit cell 20 is inserted into the accommodation hole 52, and the lower end including the negative electrode is exposed downward.

  A smoke exhaust passage 54 is formed at the longitudinal end of the battery holder 22. As shown in the enlarged view (B) of FIG. 1, the smoke exhaust passage 54 is formed in an L-shaped cross section that extends in the horizontal direction and then bends in the vertical direction. The vertical end face is connected to a smoke exhaust passage 56 formed in the negative electrode bus bar 24. The smoke exhaust port 58 on the horizontal end surface is exposed to the outside of the battery pack 10. As will be described later, the smoke exhaust temperature sensor 18 is provided in the smoke exhaust passage 54 of the battery holder 22, and the gas temperature passing through the smoke exhaust passage 54 is measured.

  The negative electrode bus bar 24 is sandwiched between the battery holder 22 and the smoke exhaust chamber cover 26. The negative electrode bus bar 24 includes, for example, a resin portion that is molded and integrated with a negative electrode formed of a conductor plate. In the negative electrode bus bar 24, a portion corresponding to each unit cell 20 accommodated in the battery holder 22, for example, a part vertically below the unit cell 20 is penetrated to form an opening 44. The opening 44 is provided so that the gas discharge valve 34 of the corresponding unit cell 20 is exposed to the smoke exhaust chamber 46 of the smoke exhaust chamber cover 26.

  The negative electrode bus bar 24 is composed of the same number of bus bar segments as the number of segments of the positive electrode bus bar 30, and the segments are connected by an insulating member such as a resin mold. A plurality of unit cells 20 sandwiched between the positive electrode bus bar segment and the negative electrode bus bar segment are connected in parallel to each other. Further, these segments are connected in series by a connection line 60 (see FIG. 1).

  As shown in the enlarged view (B) of FIG. 1, the negative electrode bus bar 24 is further provided with a smoke exhaust passage 56. The smoke exhaust passage 56 is provided at the longitudinal end of the negative electrode bus bar 24 so as to correspond to the smoke exhaust passage 54 of the battery holder 22. The smoke exhaust passage 56 of the negative electrode bus bar 24 extends in the vertical direction and is connected (communication) to the smoke exhaust chamber 46 of the smoke exhaust chamber cover 26.

  The smoke exhaust chamber cover 26 is disposed below the battery holder 22 and the negative electrode bus bar 24. The smoke chamber cover 26 has a substantially tray shape, and a space is formed between the battery holder 22 and the negative electrode bus bar 24 below the battery holder 22 and the bottom inner surface of the smoke chamber cover 26. This space becomes the smoke exhaust chamber 46.

  A smoke exhaust path is formed by the smoke exhaust chamber 46 on the smoke exhaust chamber cover 26, the smoke exhaust passage 56 of the negative electrode bus bar 24, and the smoke exhaust passage 54 of the battery holder 22. When an internal short circuit occurs in the cell 20, Joule heat increases rapidly, and the internal electrolyte etc. are decomposed and vaporized to become gas. Along with this, gas accumulates in the cell 20 and the internal pressure rises. When the internal pressure increases to the valve opening pressure, the gas discharge valve 34 on the bottom surface of the case 42 opens (thin wall portion is broken) as described above, and the gas in the case 42 is discharged into the smoke exhaust chamber 46 below the unit cell 20 (inflow). To do). The discharged gas is discharged to the outside from the smoke passage 54 of the battery holder 22 via the smoke passage 56 of the negative electrode bus bar 24. At this time, the gas temperature is measured by the smoke emission temperature sensor 18.

  FIG. 4 illustrates a hardware configuration of the control unit 12. The control part 12 is comprised from the electronic control unit (ECU) which is a central processing unit of a vehicle, for example. The control unit 12 (ECU) is constituted by a computer, for example. As illustrated in the hardware configuration diagram of FIG. 4, the control unit 12 includes a CPU 62 (Central Processing Unit), a memory 64, a hard disk drive 66 (HDD), an output unit 68 that is a display device such as a display, and an input / output interface. 70, and these devices are connected to each other via a system bus.

  The hard disk drive 66 is a computer-readable non-transitory storage medium that stores a program for executing a security control flow (fail safe flow) described later. When the program is executed by the CPU 62, the computer configuring the control unit 12 functions as each functional unit (described later) illustrated in FIG.

  The control part 12 acquires the measured value (detected value) from various sensors, and performs the security control (fail safe) with respect to the battery pack 10 according to these measured values so that it may mention later. The voltage sensors 14A, 14B, and 14C measure the voltage of the battery pack 10. As described above, the battery pack 10 is divided into a plurality (three in this embodiment) of battery segments by the segments of the positive electrode bus bar 30 and the negative electrode bus bar 24. The single cells 20 in each battery segment are connected in parallel, and the battery segments are connected in series. The voltage sensors 14 are provided in the same number as the battery segments, and measure the voltage across each battery segment.

  The current sensor 16 measures the current of the battery pack 10. For example, the current sensor 16 is provided on at least one of the positive electrode end and the negative electrode end of the battery pack 10.

  The smoke emission temperature sensor 18 is provided in the smoke emission path, and measures the temperature of gas flowing through the smoke emission path. The smoke emission temperature sensor 18 is composed of, for example, a thermistor. The smoke emission temperature sensor 18 is provided, for example, at the end of the smoke emission path, that is, in the smoke emission passage 54 of the battery holder 22.

  FIG. 5 illustrates a functional block diagram of the control unit 12. The control unit 12 includes a differentiation unit 72, a temperature differential value determination unit 74, a voltage abnormality determination unit 76, a resistance abnormality determination unit 78, a capacity abnormality determination unit 80, a flue gas temperature integration unit 82, an integration counter 84, and a smoke generation number estimation unit 86. And a restricted command section 88.

The differentiating unit 72 differentiates (dT _E / dt) the temperature value T _E of the flue gas passage 54 detected by the flue gas temperature sensor 18 and sends it to the temperature differential value determination unit 74. The temperature differential value determination unit 74 determines whether or not the temperature differential value dT _E / dt exceeds a predetermined threshold value Kth.

If, when you try to determine the presence or absence of smoke based on a comparison of the temperature value T _E and the threshold, to change the temperature value T _E according to the ambient temperature of the flue gas path (environmental temperature), the threshold setting is difficult It becomes. In addition, if it is attempted to determine the presence or absence of smoke based on the integrated value, it is difficult to set the starting point for integration. Compared to these, the differential value has a merit that it is not easily influenced by the environmental temperature because the temperature difference of the flue gas path relative to (when smoke is emitted and not smoke) becomes a criterion. Further, unlike the integral value, for example, the difference between the temperature value one count before and the temperature value of the current count may be taken, so setting of the starting point is not necessary. One count is preferably one cycle of arithmetic processing. Further, it is not necessarily a comparison with one count before, a comparison with a few counts before or one second before, etc., and a comparison between average values of several counts may also be possible.

The threshold value Kth of the temperature differential value dT _E / dt is a value obtained by experiments or the like. For example, when a predetermined environmental temperature (for example, 20 ° C.) and one unit cell 20 smokes, the gas passes through the smoke exhaust passage 54. It may be a value obtained by multiplying the difference from the temperature when passing by a margin (for example, 0.7). When the temperature differential value dT _E / dt exceeds the threshold value Kth, the temperature differential value determination unit 74 outputs an abnormality determination value (1). When the temperature differential value dT _E / dt is equal to or less than the threshold value Kth, the temperature differential value determination unit 74 outputs a normal determination value (0).

  The voltage abnormality determination part 76 acquires the both-ends voltage V1, V2, V3 of each battery segment from voltage sensor 14A, 14B, 14C. An internal short circuit can be considered as a cause of increasing the internal pressure to such an extent that any single cell 20 in the battery segment smokes. When an internal short circuit occurs among the plurality of unit cells 20 connected in parallel, current concentrates on the unit cell 20 in which the internal short circuit occurs, and the voltage across the battery segment instantaneously decreases. Furthermore, when the internal short-circuited unit cell 20 emits smoke, the unit cell 20 becomes non-conductive, and the resistance of the unit cell 20 becomes infinite. Along with this, the voltage across the battery segment (potential difference) temporarily increases. Thereafter, the voltage across the battery segment recovers (converges) to a normal voltage value.

  When capturing the temporary voltage drop described above, the voltage abnormality determination unit 76 monitors the voltage V1, V2, V3 of each battery segment detected by the voltage sensors 14A, 14B, 14C, and these are less than a predetermined threshold Vth. It is determined whether or not. This threshold determination is performed for each voltage value (V1, V2, V3). For example, when at least one of the both-end voltages V1, V2, and V3 is less than the threshold value Vth, the voltage abnormality determination unit 76 determines the battery segment (1) corresponding to the voltage value (V1, V2, V3) that is less than the threshold value Vth. The abnormality determination value (1) is output together with the identification information (ID) of ~ 3). When the voltage value is equal to or higher than the threshold value Vth, a normal determination value (0) is output.

  Further, when capturing the temporary increase in resistance described above, the voltage abnormality determination unit 76 monitors the voltage V1, V2, V3 of each battery segment detected by the voltage sensors 14A, 14B, 14C, and these are predetermined. It is determined whether or not the threshold value Vth is exceeded. This threshold determination is performed for each voltage value (V1, V2, V3). For example, when at least one of the both-end voltages V1, V2, and V3 exceeds the threshold value Vth, the voltage abnormality determination unit 76 causes the battery segments (1 to 2) corresponding to the voltage values (V1, V2, and V3) that exceed the threshold value Vth. The abnormality determination value (1) is output together with the identification information (ID) of 3). When the voltage value is less than or equal to the threshold value Vth, a normal determination value (0) is output.

  Further, instead of or in addition to the comparison between each battery segment and the threshold value, a change in voltage value between the battery segments may be considered. For example, even if the voltage abnormality determination is performed by obtaining a difference (V1−V2) between the voltage value V1 of a predetermined battery segment and the voltage value V2 of another battery segment and comparing this value with the threshold value Vth. Good. For example, after the difference value (V1−V2) is temporarily decreased and interrupted the lower limit threshold Vth− ((V1−V2) <Vth−), the difference value (V1−V2) rapidly increased and exceeded the upper limit threshold Vth + ((V1−V2)). Vth +), the abnormality determination value (1) is output for the battery segment corresponding to the voltage V1. Also, if the difference value (V1−V2) increases rapidly and exceeds the upper limit threshold value Vth + ((V1−V2)> Vth +), then rapidly decreases and interrupts the lower limit threshold value Vth− ((V1−V2) < Vth-), the abnormality determination value (1) is output for the battery segment corresponding to the voltage V2. Further, instead of the difference (V1−V2) between the voltage value V1 of the predetermined battery segment and the voltage value V2 of the other battery segment, a ratio (V1 / V2) between the two is obtained, and this and the threshold value Vth are obtained. You may compare.

  The resistance abnormality determination unit 78 acquires both-end voltages V1, V2, and V3 of each battery segment from the voltage sensors 14A, 14B, and 14C, and acquires the current value I of the battery pack 10 from the current sensor 16. The resistance abnormality determination unit 78 obtains a resistance value of each battery segment from these measured values, and determines whether or not this is less than a predetermined threshold value Rth.

  As described above, when an internal short circuit occurs in any single cell 20 in the battery segment, current concentrates on the internal short circuited cell 20 and the resistance of the battery segment decreases instantaneously. Furthermore, when the internal short-circuited unit cell 20 emits smoke, the unit cell 20 becomes non-conductive, and the resistance of the unit cell 20 becomes infinite. Along with this, the resistance of the battery segment temporarily increases. After that, it recovers (converges) to the normal resistance value.

  When capturing the temporary decrease in resistance, the resistance abnormality determination unit 78 determines the voltage V1, V2, V3 of each battery segment detected by the voltage sensors 14A, 14B, 14C and the current value I of the battery pack 10. Then, the resistance value (R1, R2, R3) of each battery segment is obtained, and it is determined whether or not these are less than a predetermined threshold value Rth. This threshold determination is performed for each battery segment. For example, when at least one of the resistance values R1, R2, and R3 is less than the threshold value Rth, the resistance abnormality determination unit 78 determines the battery segment (1) corresponding to the resistance value (R1, R2, R3) that is less than the threshold value Rth. The abnormality determination value (1) is output together with the identification information (ID) of ~ 3). When the resistance value is equal to or greater than the threshold value Rth, a normal determination value (0) is output.

  When capturing the temporary increase in resistance, the resistance abnormality determination unit 78 detects the voltage V1, V2, V3 of each battery segment detected by the voltage sensors 14A, 14B, 14C and the current value of the battery pack 10. From I, the resistance value (R1, R2, R3) of each battery segment is obtained, and it is determined whether or not these exceed a predetermined threshold value Rth. This threshold determination is performed for each battery segment. For example, when at least one of the resistance values R1, R2, and R3 exceeds the threshold value Rth, the resistance abnormality determination unit 78 causes the battery segments (1 to 2) corresponding to the resistance values (R1, R2, and R3) that exceed the threshold value Rth. The abnormality determination value (1) is output together with the identification information (ID) of 3). When the resistance value is equal to or less than the threshold value Rth, a normal determination value (0) is output.

  Further, instead of or in addition to the comparison between each battery segment and the threshold value, a resistance value change between the battery segments may be considered. For example, even if the voltage abnormality determination is performed by obtaining a difference (R1-R2) between the resistance value R1 of a predetermined battery segment and the resistance value R2 of another battery segment and comparing this value with the threshold value Rth. Good. For example, after the difference value (R1−R2) has been temporarily decreased and interrupted the lower limit threshold value Rth− ((R1−R2) <Rth−), it rapidly increased and exceeded the upper limit threshold value Rth + ((R1−R2)> Rth +), the abnormality determination value (1) is output for the battery segment corresponding to the resistor R1. Also, if the difference value (R1-R2) increases rapidly and exceeds the upper limit threshold value Rth + ((R1-R2)> Rth +), then rapidly decreases and interrupts the lower limit threshold value Rth- ((R1-R2) < Rth−), the abnormality determination value (1) is output for the battery segment corresponding to the resistor R2. Further, instead of the difference (R1−R2) between the resistance value R1 of the predetermined battery segment and the resistance value R2 of the other battery segment, a ratio (R1 / R2) between them is obtained, and this and the threshold value Rth are obtained. You may compare.

  The capacity abnormality determining unit 80 determines whether or not each battery segment has a capacity (SOC) abnormality. The capacity of each battery segment is determined as follows. For example, the voltage across each battery segment when the battery pack 10 is not energized is OCV, and the voltage of each battery segment detected by the voltage sensors 14A, 14B, 14C or the current detected by the current sensor 16 The SOC is calculated based on the integrated value. Further, as a method for calculating the OCV, instead of the above, ΔV / ΔI is obtained from the fluctuation range ΔV of the voltage of each battery segment detected by the voltage sensors 14A, 14B, 14C and the fluctuation range ΔI of the current value detected by the current sensor 16. The OCV may be calculated from this intercept.

  When the unit cell 20 in the battery segment emits smoke and becomes non-conductive, the capacity of the cell segment decreases by the amount of the unit cell. As the capacity decreases, the SOC change per unit capacity (ΔSOC) increases. The capacity abnormality determination unit 80 determines whether or not the change in SOC per unit capacity (ΔSOC) exceeds a predetermined threshold value Dth. This threshold determination is performed for each battery segment. For example, when the fluctuation range ΔSOC1 of SOC1 per unit capacity exceeds the threshold value Dth, the capacity abnormality determination unit 80 performs an abnormality together with the identification information (ID) of the battery segments (1 to 3) corresponding to the SOC exceeding the threshold value Dth. The judgment value (1) is output. When the SOC fluctuation range ΔSOC per unit capacity is equal to or less than the threshold value Dth, a normal determination value (0) is output.

  Further, the SOC fluctuation widths per unit capacity (ΔSOC) between the battery segments may be compared. For example, when the difference (ΔSOC1−ΔSOC2) or the ratio (ΔSOC1 / ΔSOC2) between the SOC fluctuation width (ΔSOC1) of a predetermined battery segment and the SOC fluctuation width (ΔSOC2) of another battery segment exceeds a predetermined threshold Dth , The abnormality determination value (1) may be output for the battery segment corresponding to ΔSOC1.

  The smoke emission temperature integrating unit 82 acquires temperature values from the smoke emission temperature sensor 18 and integrates them. If the temperature is integrated before the unit 20 emits smoke, the estimation accuracy of the number of smoke is reduced, so that the accumulation starts when it is determined that there is smoke.

In the present embodiment, as a reference for determining that the unit cell 20 emits smoke, a double check is performed between the presence or absence of a temperature abnormality in the smoke generation path and the presence or absence of an abnormality in the electrical system. That is, the temperature differential value dT _E / dt exceeds the threshold value Kth, and an abnormality determination value (1) is obtained from at least one of the voltage abnormality determination unit 76, the resistance abnormality determination unit 78, and the capacity abnormality determination unit 80. ) Is output, it is determined that the single battery 20 is smoking. By performing such a double check, it is possible to determine smoke generation with high accuracy.

The flue gas temperature integration unit 82 outputs the abnormality determination value (1) from the temperature differential value determination unit 74, and at least one of the voltage abnormality determination unit 76, the resistance abnormality determination unit 78, and the capacity abnormality determination unit 80. when One from the abnormality determination value (1) is output, the time when the temperature differential value dT E _/ dt exceeds the threshold value Kth as starting point to begin accumulating temperature value T _E of the flue gas temperature sensor 18 . Further, the battery segment identification information (ID) of the abnormality determination target is acquired from the voltage abnormality determination unit 76, the resistance abnormality determination unit 78, and the capacity abnormality determination unit 80.

Note that the temperature at the starting point may be corrected when the temperature value _TE is integrated. For example, assuming that the detected value of the smoke temperature sensor 18 at the time of calculation is T ₀ , ∫T = ∫ (T _E −T ₀ ) may be used. By performing such correction, it becomes less susceptible to the influence of the environmental temperature (ambient temperature).

Integration of temperature values (smoke emission temperature) of the smoke emission temperature sensor 18 is performed over a predetermined standby time T _ref . For example, the flue gas temperature integration unit 82 drives the integration counter 84 from the time when the temperature differential value dT _E / dt exceeds the threshold value Kth, and counts up to the standby time T _ref (integration time). Thus, by integrating the smoke emission temperature over a predetermined standby time, the difference between the case where a plurality of single cells 20 smoke at the same time and the case where smoke occurs with a time difference is reduced.

FIG. 6 shows an example in which three unit cells 20 smoke at the same time, and FIG. 7 shows an example in which three unit cells smoke sequentially within the standby time T _ref with a time difference. Measurements of flue gas temperature sensor 18 in the upper part of FIG. 6 and FIG. 7 time variation of (flue gas temperature) T _E is shown in the middle differential value is shown, the integrated value is the lower (integrated value) It is shown. Further, the threshold value Kth is indicated in the middle differential value, and the standby time T _ref is indicated in the lower integral value.

  The gas discharged from the unit cell 20 passes through the smoke emission temperature sensor 18 while being mixed with the air in the smoke emission chamber 46. While the temperature of the mixed gas decreases below the gas temperature in the process of mixing with the air in the smoke exhaust chamber 46, the temperature becomes closer to the gas temperature at the time of discharge as the number of smoke generations increases, that is, as the gas concentration increases.

Comparing the measured value T _E of FIG. 6 and FIG. 7, the temperature value T _E each time the number in the simultaneous smoke (Figure 6) increases will increase. On the other hand, in the time difference smoke generation (FIG. 7), since the smoke pattern is such that the gas of the next unit cell 20 passes after the gas of the previous unit cell 20 passes through the smoke emission temperature sensor 18, 1 is at most. It stops at the temperature value at the time of this smoke generation.

In contrast, the integrated value of the temperature (integrated value) ∫T _E is at the end t1 of the waiting time T _ref, no significant difference exits simultaneous smoke and (6) the time difference smoke (Figure 7). As described above, in this embodiment, by obtaining the integrated value of the smoke temperature T _E (integrated value), regardless of the co-fuming and time difference smoke, it is possible to estimate the accurate smoke number.

The flue gas temperature integration unit 82 obtains the smoke generation temperature integration value ∫ T _E from the time when the temperature differential value dT _E / dt exceeds the threshold value Kth until the standby time T _ref elapses, and this is calculated as the smoke generation number estimation unit. Send to 86. The smoke number estimation unit 86, smoke number map fuming temperature integrated value ∫T _E fuming number (estimated value) is associated are stored. Smoke number estimating unit 86, and a smoke number mapped smoke temperature integrated value ∫T _E, obtains an estimate N of the smoke number and sends it to the limit headquarters 88. Also, identification information (ID) of the battery segment in which smoke is generated is sent together with the estimated number N of smoke.

  The restriction command unit 88 stores a security control map in which the number of smoke generations and security control (fail-safe) items are associated with each other. For example, when the number of smoke generation is relatively small, for example, less than 5% of the unit cell 20 of the battery segment, input / output power limit (Win / Wout) is associated as a safety control item. Further, when the number of smoke generation is relatively large, for example, 60% or more of the unit cell 20 of the battery segment, a stop (Ready-Off) of the vehicle system is associated as a safety control item. In addition, when the number of smoke generation is an intermediate number, for example, 30% or more and less than 60% of the unit cell 20 of the battery segment, the system main relay that connects the battery module and a load such as a rotating electric machine is shut off. Corresponding as an item.

  The restriction command unit 88 refers to the identification information (ID) of the battery segment in which smoke is generated, obtained from the smoke number estimation unit 86, and calls the past smoke generation number generated in the battery segment from the hard disk drive 66. Further, the estimated value N of the number of smoke obtained from the smoke number estimation unit 86 is added to the past number of smoke, and the security control item corresponding to the number (cumulative number) is called (selected) from the security control map. Furthermore, based on the called security control item, a control command is output to each electric device of the vehicle.

FIG. 8 illustrates a flowchart of security control according to the present embodiment. The flowchart is started, for example, when the vehicle system is activated (Ready-On). The temperature differential value determination unit 74 acquires the differential value dT _E / dt of the temperature value of the smoke emission temperature sensor 18 from the differential unit 72 at a predetermined cycle, and whether the temperature differential value dT _E / dt exceeds the threshold value Kth. It is determined whether or not (S10).

When the temperature differential value dT _E / dt is equal to or less than the threshold value Kth, it is determined that no smoke is generated in the unit cell 20, and the process proceeds to the flow end point (Return). When the temperature differential value dT _E / dt exceeds the threshold value Kth, the temperature differential value determination unit 74 outputs the abnormality determination value (1) to the flue gas temperature integration unit 82. In the flue gas temperature integrating unit 82, at least one of voltage, resistance, and capacity is abnormal with reference to the determination signals output from the voltage abnormality determining unit 76, the resistance abnormality determining unit 78, and the capacity abnormality determining unit 80. It is determined whether or not it is determined to be present (S12).

If no abnormality determination value is output from any of the voltage, resistance, and capacity, it is determined that no smoke is generated in the unit cell 20, and the process proceeds to the flow end point (Return). If it is determined that at least one of the voltage, resistance, and capacity is abnormal, the smoke emission temperature integrating unit 82 starts counting the standby time T _ref by the integrating counter 84, and the temperature differential value dT _E / dt There begin accumulating flue gas temperature value _{T E} from the threshold excess time that exceed the threshold Kth (S14).

In addition, over-threshold point and the voltage, resistance, and if the delay occurs between the abnormality determination of capacitance, voltage, resistance, and to begin accumulating temperature value T _E from the threshold excess time prior to abnormality determination of capacitance May be. In this case, voltage, resistance, and when none of the capacity is determined that no abnormality, the flue gas temperature integration unit 82 may discard the accumulated value ∫T _E so far.

Integration of the flue gas temperature value _{T E} is performed over the waiting time _{T ref} from the threshold excess time (S16). The waiting time is counted by the integration counter 84.

When the accumulated time reaches the standby time T _ref , the smoke temperature integrating unit 82 sends the accumulated value ∫ T _E of the smoke temperature at that time to the smoke generation number estimating unit 86. Smoke number estimating unit 86 refers to the smoke number map, it obtains a smoke number corresponding to the integrated value ∫T _E flue gas temperature (an estimated value) (S18), and the smoke number N, fuming occurred The battery segment identification information (ID) is sent to the restriction command unit 88.

The restriction command unit 88 refers to the identification information (ID) of the battery segment in which smoke is generated, acquired from the smoke generation number estimation unit 86, and the past number of smoke generated in the battery segment (cumulative number) N _k− Call ₁ Furthermore, the smoke number N acquired from the smoke number estimation unit 86 is added to the past smoke number N _k−1 to obtain the current cumulative number N _k (S20). When N _k−1 = 0, N _k = N.

Further, the restricted command unit 88 determines whether or not the cumulative number _Nk exceeds a predetermined threshold A1 (S22). When the threshold value A1 is exceeded, the restriction command unit 88 refers to the security control map and selects and instructs to stop the vehicle system (Ready-Off) (S24). As a result, the system of the vehicle is stopped, and thus this flow ends.

When the cumulative number N _k is equal to or less than the threshold A1, the restriction command unit 88 determines whether or not the cumulative number N _k exceeds the threshold A2 (<A1) (S26). When the threshold value A2 is exceeded, the restriction command unit 88 refers to the security control map and selects and instructs the system main relay to be shut off (SMR-OFF) (S28). As a result, the power supply from the battery pack 10 is cut off, and thus this flow ends.

When the cumulative number _Nk is equal to or less than the threshold value A2, the restriction command unit 88 issues a selection command for input / output power restriction (Win / Wout) (S30). As described above, by executing the security control according to the number of smoke generation, it is possible to efficiently use the battery pack.

  DESCRIPTION OF SYMBOLS 10 Battery pack, 12 Control part, 14A, 14B, 14C Voltage sensor, 16 Current sensor, 18 Flue gas temperature sensor, 20 Cell, 34 Gas discharge valve, 46 Flue gas chamber, 54 Flue gas passage of battery holder, 56 Negative electrode Smoke passage of bus bar, 72 differential unit, 74 temperature differential value determination unit, 76 voltage abnormality determination unit, 78 resistance abnormality determination unit, 80 capacity abnormality determination unit, 82 flue gas temperature integration unit, 84 integration counter, 86 smoke generation number estimation Department, 88 Restricted Command.

Claims (1)

A battery pack control system in which a plurality of cells are connected in parallel,
A smoke temperature sensor provided in a smoke exhaust path through which gas discharged from the unit cell provided in the battery pack flows;
A voltage sensor for measuring the voltage of the battery pack;
A current sensor for measuring the current of the battery pack;
A control unit that performs security control on the battery pack according to the measured values of the smoke temperature sensor, the voltage sensor, and the current sensor;
With
The controller is
When the differential value of the flue gas temperature exceeds a predetermined threshold and it is determined that at least one of the voltage, resistance, and capacity of the battery pack is abnormal based on the voltage and current of the battery pack A smoke temperature integrating unit that starts counting the smoke temperature starting from the time when the threshold is exceeded,
Based on the integrated value of the smoke emission temperature after a predetermined standby time from the time when the threshold is exceeded, a smoke generation number estimation unit that estimates the number of smoke generation of single cells in the battery pack;
Based on the estimated number of smoke generation, a command unit for selecting and commanding the predetermined security control item from a plurality of safety control items,
A battery pack control system comprising:

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