JP2007250408A - Device for cooling battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cool a capacity adjusting circuit upon its temperature rise irrespective of the temperature of a battery pack. <P>SOLUTION: When the temperature of the capacity adjusting circuit becomes higher than a first predetermined temperature (S200), the RPM of a cooling fan is controlled based on the temperature of the capacity adjusting circuit. This enables cooling of the capacity adjusting circuit upon its temperature rise irrespective of the temperature of the battery pack. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery pack cooling apparatus.

  Conventionally, capacity adjustment amount is calculated for each cell by calculating the capacity adjustment amount for each cell, obtaining the discharge time based on the calculated capacity adjustment amount, and performing discharge for each cell for the determined discharge time. There is known a capacity adjustment device that performs the above (see Patent Document 1).

JP-A-10-322925

  In the capacity adjustment apparatus described in Patent Document 1, a cooling fan for cooling the assembled battery is provided, and control is performed based on the temperature of the assembled battery. If the cell is discharged through the discharge circuit during capacity adjustment, the temperature of the discharge circuit rises. However, since the cooling fan is controlled based on the temperature of the assembled battery, the discharge circuit can be effectively cooled. The problem that it is not possible arises.

  The battery pack cooling device according to the present invention has a discharge unit that discharges each cell in order to make the capacity of the plurality of cells uniform, when the temperature of the discharge unit is higher than a first predetermined temperature. The cooling means for cooling at least the assembled battery and the discharging means is controlled based on the temperature of the battery.

  According to the battery pack cooling device of the present invention, when the temperature of the discharge means is higher than the first predetermined temperature, the cooling means is controlled based on the temperature of the discharge means. The discharging means can be effectively cooled.

-First embodiment-
FIG. 1 is a diagram illustrating a configuration of a battery pack cooling apparatus according to the first embodiment. This assembled battery cooling device is mounted and used in, for example, a hybrid vehicle. The assembled battery 100 is, for example, a lithium ion battery, and is configured by connecting n (n: natural number) cells C1 to Cn that can be charged and discharged in series. Each of the cells C1 to Cn is grouped into four to constitute modules M1, M2,. The total voltage sensor 10 detects the total voltage of the assembled battery 100.

  The cell controllers CC1, CC2,..., CCt provided for the modules M1, M2,..., Mt manage the cells for the corresponding modules M1, M2,. For example, the cell controller CC1 controls charging / discharging of the four cells C1 to C4 included in the module M1.

  The battery controller 30 communicates with the cell controllers CC1 to CCt by serial communication via the transmission terminal SD and the reception terminal RD, and controls the cell controllers CC1 to CCt to manage the assembled battery 100.

  The temperature sensor 20 detects the temperature of the assembled battery 100 and outputs it to the battery controller 30. The cooling fan 50 cools the assembled battery 100 and a capacity adjustment circuit described later based on a command from the battery controller 30.

  FIG. 2 is a diagram illustrating a positional relationship among the cooling fan 50, the battery controller 30, the cell controllers CC <b> 1 to CCt, and the assembled battery 100. As shown in FIG. 2, the cooling fan 50, the battery controller 30, the cell controllers CC1 to CCt, and the assembled battery 100 are provided in the same cooling passage 60, and the battery controller 30, the cell controllers CC1 to CCt, And the assembled battery 100 is arrange | positioned in the lee of the cooling air which generate | occur | produces when the cooling fan 50 act | operates. The battery controller 30 and the cell controllers CC1 to CCt are integrated. Further, the cell controllers CC <b> 1 to CCt are in contact with the cooling passage 60 through the heat conductive sheet 74.

  FIG. 3 is a diagram showing a detailed circuit configuration of the cell controller. Here, the cell controller CC1 will be described. However, the other cell controllers CC2 to CCt have the same circuit configuration. The cell controller CC1 includes an IC 11, an A / D converter 12, an interface (IF) 13, a photocoupler 14, resistors R1 to R4, and switches S1 to S4.

  The A / D converter 12 converts the voltage between the terminals of each of the cells C1 to C4 into a digital signal and transmits it to the IC11. The interface 13 communicates with the battery controller 30 by serial communication. Note that the interface 13 and the IC 11 are insulated by a photocoupler 14. Further, the internal circuit of the assembled battery 100 has a high voltage of about 400 V at the maximum, and a capacity adjustment circuit constituted by wiring of a voltage detection circuit to the A / D converter 12, resistors R1 to R4 and switches S1 to S4. The (discharge circuit) is built in the cell controller CC1 to avoid routing the high voltage circuit.

  A series circuit of a resistor and a switch is connected in parallel to each of the cells C1 to C4. A series circuit composed of a resistor and a switch is a capacity adjustment circuit (discharge circuit) of each cell. For example, a series circuit composed of the resistor R1 and the switch S1 constitutes a capacity adjustment circuit of the cell C1. The discharge capacity of the corresponding cells C1 to C4 is discharged via the resistors R1 to R4, so that the charge capacity of each cell can be adjusted. The switches S1 to S4 are controlled to be opened and closed by the IC 11, respectively. For example, when the switch S1 is closed, the cell C1 is discharged via the resistor R1.

  The resistance values of the resistors R1 to R4 are the same, for example, 200Ω. The capacity adjustment amount (discharge amount) of each cell depends on the closing time of the corresponding switches S1 to S4, and the capacity adjustment amount is controlled by controlling the switch opening and closing time.

  Here, a method of detecting the open voltages Vc1 to Vcn of the cells C1 to Cn will be described. The open-circuit voltages Vc1 to Vcn of the cells C1 to Cn are detected by an A / D converter of the cell controller, converted into a digital signal, sent to the IC of the cell controller, and further supplied to the battery controller 30 via the interface IF. Sent to.

The detection timing of the cell open voltages Vc1 to Vcn may be (I) immediately before the start of discharging the assembled battery 100, (II) a current decay region immediately before the end of full charge, (III) during discharging, or the like.
(I) Although the open circuit voltage can be detected at the timing immediately before the start of discharge, the voltage detection operation in each cell controller CC1 to CCt and the transmission operation of the detection result from each cell controller CC1 to CCt to the battery controller 30 Since the battery pack 100 must wait for the discharge from the assembled battery 100 to the load during the process, high-speed A / D conversion and communication speed are required. However, there are few restrictions on detection timing.
(II) Since the charging current is small in the current decay region immediately before the end of full charge, the voltage drop due to the internal resistance of each cell is small, and a voltage close to the open circuit voltage can be detected. Since it is during charging, it is not necessary to communicate with high-speed A / D conversion, but the detection timing is limited to the end of charging.
(III) During discharge, the discharge voltages Vc1 to Vcn and the discharge current I of each cell are measured, and the voltage-current characteristic (V = E-IR) for each cell is linearly regressed to estimate the open circuit voltage E of the cell. be able to. However, since the calculation is performed for each cell, the calculation load increases.

  Note that if the switches S1 to Sn are closed during the detection of the open circuit voltages Vc1 to Vcn and the cells are discharged by the resistors R1 to Rn, the measurement error of the open circuit voltage Vc becomes large. The closing of S1 to Sn is prohibited.

  Each cell controller CC1 to CCt detects the open voltage Vc1 to Vcn of each cell and sends it to the battery controller 30 via the interface IF. The battery controller 30 sets the minimum cell voltage among the open-circuit voltages Vc1 to Vcn acquired from the cell controllers CC1 to CCt to the capacity adjustment target voltage Vv, and sets the voltage of each cell to the value of the capacity adjustment target voltage Vv. Therefore, the bypass adjustment amounts (capacity adjustment amounts) Cct1 to Cctn necessary for this purpose are obtained.

  FIG. 4 is a diagram for obtaining the bypass adjustment amounts Cct1 to Cctn from the open-circuit voltages Vc1 to Vcn and the capacity adjustment target voltage Vv of each cell. For example, when the open circuit voltage of the cell is 3.45V and the capacity adjustment target voltage Vv is 3.25V, the bypass adjustment amount is 0.6 (= 1.6−1.0) Ah. The battery controller 30 stores the data shown in FIG. 4 in a memory (not shown) in advance.

  In the battery pack cooling apparatus according to the first embodiment, the discharge amount at the time of capacity adjustment is calculated for each predetermined period ΔT, and the calculated discharge amount is determined based on the open circuit voltage of the cell. Bypass adjustment amounts Cct1 to Cctn Until they match, the switches S1 to Sn provided corresponding to the cells C1 to Cn are turned on, and a bypass adjustment current is allowed to flow. Here, the process of repeatedly subtracting the actual discharge amount from the bypass adjustment amounts Cct1 to Cctn obtained based on the open circuit voltage of the cell is repeated, and the cell discharge is performed until the bypass adjustment amounts Cct1 to Cctn after subtraction become zero. I do. The battery controller 30 performs processing for subtracting the bypass adjustment amounts Cct1 to Cctn.

For example, the bypass adjustment amount Cctn of the cell Cn is obtained by the following equation (1). In equation (1), the value obtained by multiplying the average bypass current value by the bypass time (discharge time) is the discharge amount at the time of capacity adjustment.
Cctn = Cctn−average bypass current In × bypass time (1)
However, the average bypass current In is a bypass current that flows when the capacity of the cell Cn is adjusted (during discharge), and the time average voltage Vcan of the cell Cn and the resistance of the resistor Rn provided corresponding to the cell Cn. Based on the value R, it can be obtained by the following equation (2).
In = Vcan / R (2)

A method for obtaining the time average voltage of each cell will be described. The battery controller 30 obtains the time average voltage of each cell by acquiring the voltage of each cell every predetermined period ΔT during capacity adjustment. For example, assuming that the voltages of the cells Cn detected at each predetermined period ΔT are Vcn_smp1, Vcn_smp2,. .
Vcan = (Vcn_smp1 + Vcn_smp2 + ... + Vcn_smpk) / k (3)

The calculation of the time average voltage according to the above equation (3) is performed for every predetermined period ΔT for all the cells C1 to Cn. In addition, the battery controller 30 performs abnormality determination based on the calculated time average voltages Vca1 to Vcan of each cell. Here, when the relationship of the following equation (4) is satisfied, no abnormality has occurred, and when the relationship of the equation (4) is not satisfied, sampling failure, cumulative error at voltage detection, voltage detection error For this reason, it is determined that the value of the time average voltage is abnormal. However, Vmin is a predetermined lower limit value, and Vmax is a predetermined upper limit value.
Vmin <Vca1, Vca2,..., Vcan <Vmax (4)

  When the time average voltages Vca1 to Vcan do not satisfy the relationship of Expression (4) and the value is determined to be abnormal, the value of the time average voltage determined to be abnormal is replaced with a predetermined value. The predetermined value is an average voltage value when charge / discharge control is performed, for example, a voltage value when the SOC of the cell is 50%.

  In the assembled battery cooling device in the first embodiment, the cooling fan 50 is controlled based on the temperature of the capacity adjusting circuit in the cell controllers CC1 to CCt and the temperature of the assembled battery 100 when adjusting the capacity between cells. To do.

  FIG. 5 and FIG. 6 are flowcharts showing the contents of processing performed by the assembled battery cooling device in the first embodiment. The process of step S1 to step S4 is a process performed by each cell controller CC1 to CCt, and the process of step S10 to step S120 is a process performed by the battery controller 30. When the system is powered on, each of the cell controllers CC1 to CCt starts the process of step S1.

  In step S1, the cell controllers CC1 to Cct detect the open voltages Vc1 to Vcn of the cells C1 to Cn, and the process proceeds to step S2. In step S <b> 2, the open-circuit voltages Vc <b> 1 to Vcn of each cell detected in step S <b> 1 are transmitted to the battery controller 30.

  In step S10, the battery controller 30 determines whether or not the open voltages Vc1 to Vcn of all the cells C1 to Cn have been received. If it is determined that the open voltages Vc1 to Vcn of all cells have not been received, the process waits in step S10. If it is determined that the open voltages Vc1 to Vcn of all cells have been received, the process proceeds to step S20.

  In step S20, among the open voltages Vc1 to Vcn of all cells received in step S10, the minimum cell voltage is set to the capacity adjustment target voltage Vv, and the process proceeds to step S30. In step S30, each cell is determined based on the open-circuit voltages Vc1 to Vcn and the capacity adjustment target voltage Vv of each cell and data (see FIG. 4) relating to the bypass adjustment amount (capacity adjustment amount) stored in a memory (not shown). Bypass adjustment amounts Cct1 to Cctn necessary for aligning the voltage to the capacity adjustment target voltage Vv are obtained.

  In step S40 following step S30, time average voltages Vca1 to Vcan of each cell are obtained. As described above, the time average voltage is obtained for each cell based on the cell voltage detected every predetermined period Δt. When the time average voltage for each cell is obtained, the process proceeds to step S50. In step S50, it is determined whether or not an abnormality has occurred in the time average voltages Vca1 to Vcan obtained in step S40. As described above, if the time average voltage is larger than the predetermined lower limit value Vmin and smaller than the predetermined upper limit value Vmax, it is determined that the value of the time average voltage is normal, and is equal to or lower than the predetermined lower limit value Vmin, or When the value is equal to or higher than the predetermined upper limit value Vmax, it is determined that the value of the time average voltage is abnormal. If it is determined that the value of the time average voltage is abnormal, the process proceeds to step S60, and if it is determined to be normal, the process proceeds to step S70.

  In step S60, the value of the time average voltage determined to be abnormal is replaced with a predetermined value, and the process proceeds to step S70. In step S70, it is determined whether or not the bypass adjustment amounts Cct1 to Cctn of each cell are larger than zero. As described above, the process of subtracting the bypass adjustment amounts Cct1 to Cctn is performed for each predetermined period ΔT according to both actual discharges. If it is determined that the bypass adjustment amount is greater than 0, the process proceeds to step S80. If it is determined that the bypass adjustment amount is 0 or less, the process proceeds to step S110.

In step S80, the temperature of the capacity adjustment circuit (discharge circuit) provided in the cell controllers CC1 to CCt is estimated. The estimated temperature (estimated temperature in the casing of the cell controller) Tccn of the capacity adjustment circuit is expressed by the following equation (5).
Tccn = Ambient temperature T + Temperature increase ΔTup due to capacity adjustment (5)

  In equation (5), the ambient temperature T is the ambient temperature of the cell controller including the capacity adjustment circuit, and is obtained as follows according to the operating state of the cooling fan 50 and the presence or absence of an abnormality in the temperature sensor 20.

= When the cooling fan is stopped (including when the cooling fan is abnormal) =
When the cooling fan 50 is stopped, the ambient temperature T of the capacity adjustment circuit can be approximated by the temperature of the assembled battery 100. Therefore, the temperature detected by the temperature sensor 20 is used as the ambient temperature T. However, when the temperature sensor 20 is abnormal and the temperature of the assembled battery 100 cannot be accurately detected, a method for rotating the cooling fan, which will be described later, is used.

= When the cooling fan is rotating =
When the cooling fan 50 is rotating, if the cooling passage 60 (see FIG. 2) is connected to the vehicle interior, the ambient temperature T of the capacity adjustment circuit can be approximated by the temperature in the vehicle interior. The temperature in the passenger compartment can be acquired from an air conditioner controller (not shown). In addition, when the cooling passage 60 is connected to the outside of the passenger compartment, the ambient temperature T of the capacity adjustment circuit can be approximated by the temperature outside the passenger compartment. The temperature outside the passenger compartment can be acquired from an engine controller (not shown). Further, when the cooling passage 60 is connected to the vehicle interior and the exterior of the vehicle interior, the ambient temperature T is set by weighting the indoor temperature and the outdoor temperature based on the ratio of the inside air and the outside air flowing into the cooling passage 60. Ask.

  Next, a method for obtaining the temperature rise ΔTup by adjusting the capacity in Expression (5) will be described. FIG. 7A is a diagram of the cell controller viewed from the lateral direction, and FIG. 7B is a diagram of the cell controller viewed from the front (rear). As shown in FIG. 7B, the casing 70 of the cell controller is provided with a plurality of slits 71 for allowing air to pass through. Thereby, the cooling air generated by the cooling fan 50 flows in the cell controller from the left side to the right side in the figure (see FIG. 7A).

  As shown in FIG. 7A, the capacity adjustment circuit 72 provided in the cell controller is provided on the substrate 73. The substrate 73 is grounded to the cooling passage 60 via the heat conductive sheet 74. Therefore, a part of the heat generated by the capacity adjustment circuit 72 performing the capacity adjustment (discharge) of the cell is released to the cooling passage 60 via the lower part of the housing 70. A part of the amount of heat generated during the capacity adjustment is released into the casing of the cell controller, and a part of the quantity is released outside the casing 70 through the slit 71. That is, of the amount of heat generated during capacity adjustment, the amount of heat excluding the amount of heat released to the cooling passage 60 and the amount of heat released outside the housing 70 via the slit 71 is the temperature of the capacity adjustment circuit 72. Contribute to the rise.

  The calculation method of the temperature increase ΔTup due to the capacity adjustment will be briefly described. First, the calorific value q (W) generated by the capacity adjustment (discharge) in the capacity adjustment circuit is obtained, and based on the obtained calorific value q (W), An amount of heat qup (W) for increasing the temperature in the casing of the cell controller is obtained. Then, based on the obtained heat quantity qup (W), a temperature increase ΔTup due to capacity adjustment is obtained. Hereinafter, a method for obtaining the temperature increase ΔTup due to the capacity adjustment will be described separately in the transient state of the temperature increase due to the capacity adjustment and in the steady state.

A calorific value q (W) generated by capacity adjustment (discharge) by the capacity adjustment circuit is obtained from the following equation (6).
q (W) = Ib1 (A) × Vc1 (V) + Ib2 (A) × Vc2 (V) +... + Ibn (A) × Vcn (V) (6)
However, Vc1 to Vcn are voltage values of the cells C1 to Cn and are detected by the cell controllers CC1 to CCt. Ib1 to Ibn are bypass currents of the respective cells, and are obtained by dividing the voltage values Vc1 to Vcn of the respective cells by the resistance values R of the resistors R1 to Rn provided corresponding to the respective cells.

= Transient state =
In the transient state of the temperature increase due to the capacity adjustment, the heat quantity qup (W) that raises the temperature in the casing of the cell controller equipped with the capacity adjustment circuit out of the calorific value q (W) is expressed by the following equation (7). Ask.
qup (W) = {q− (Aco × ΔTco × Tr / t)} × {(Vol_con−Vol_fan / A × B) / Vol_con} (7)
Here, each symbol in Formula (7) is as follows.
q (W): Amount of heat generated by capacity adjustment Aco (m ² ): Ground area Tr (W / m · K) of casing 70 of cell controller: Thermal conductivity t (m) of casing 70 of cell controller: Cell Thickness A (m ² ) of controller casing 70: cross-sectional area B (m ² ) of cooling passage 60: total area Vol_fan (liter / s) of air inlet / outlet (slit) of casing 70 of cell controller: cooling fan Air flow volume per unit time Vol_con (liter): Cell controller housing volume ΔTco (K): Temperature difference between the temperature in the housing 70 of the cell controller and the cooling passage 60 to which the housing 70 is grounded Is represented by the following equation (8). However, the initial value is 0.
ΔTco = (previous value of calculation of temperature inside casing of cell controller) − (temperature of cooling passage 60 in contact with cell controller CCn) (8)

  In Expression (7), (Aco × ΔTco × Tr / t) represents the amount of heat released to the cooling passage 60 through the grounded portion of the cell controller housing 70. Further, {(Vol_con−Vol_fan / A × B) / Vol_con} in the equation (7) remains in the casing 70 except for the amount of air flowing out from the slit 71 in the amount of air in the casing 70. It represents the ratio of air volume.

The temperature rise ΔTup is expressed by the following equation (9).
ΔTup = ∫ [qup / {Vol_con × pressure / (gas constant × temperature) × molecular weight of air × specific heat of air}] dt (9)
However,
Pressure: 1 atm gas constant: 8.31 (J / mol · K)
Temperature: 25 ° C
Molecular weight of air: 28 (g / mol)
Specific heat of air: 1 (W · s / g · K)

  The time integration in equation (9) approximates the calculation cycle of the battery controller 30 as ΔT.

= During steady state =
In the steady state, in Equation (7), ΔTco approaches a constant value, and qup approaches 0. As a result, the temperature in the casing 70 of the cell controller is saturated at a certain value. Since the amount of heat given to the cell controller casing 70 before the cup reaches zero is determined by the amount of discharge of the cells at the time of capacity adjustment and the flow velocity in the cooling passage 60, the temperature rise ΔTup in the casing in the steady state is reduced. It is possible to obtain ΔTup in a steady state by obtaining a table by an experiment or the like and referring to this table.

  FIG. 8 is a table showing the relationship between the discharge amount of the cell during capacity adjustment, the flow rate of the cooling passage 60, and ΔTup in the steady state. This table is stored in a memory (not shown). The battery controller 30 obtains ΔTup in the steady state based on the discharge amount of the cell at the time of capacity adjustment, the flow rate of the cooling passage 60, and the table shown in FIG. The discharge amount of the cell is obtained by calculation, and the flow rate of the cooling passage 60 is obtained based on the operating state of the cooling fan 50.

  When the ambient temperature T of the capacity adjustment circuit and the temperature increase ΔTup due to capacity adjustment are respectively obtained, the estimated temperature Tccn of the capacity adjustment circuit is calculated from the above equation (5). When the estimated temperature Tccn of the capacity adjustment circuit is obtained in step S80 of the flowchart shown in FIG. 5, the process proceeds to step S90.

  In step S90, the cooling fan 50 is controlled based on the estimated temperature Tccn of the capacity adjustment circuit and the temperature of the assembled battery 100 detected by the temperature sensor 20. Details of the cooling fan control performed in step S90 will be described with reference to the flowchart shown in FIG.

  In step S200 of the flowchart shown in FIG. 6, it is determined whether or not the estimated temperature Tccn of the capacity adjustment circuit is higher than 70 ° C. which is the first predetermined temperature. If it is determined that the estimated temperature Tccn of the capacity adjustment circuit is higher than 70 ° C., the process proceeds to step S210. In step S210, the fan rotation speed of the cooling fan 50 is controlled based on the estimated temperature Tccn of the capacity adjustment circuit. FIG. 9 is a diagram showing the relationship between the estimated temperature Tccn of the capacity adjustment circuit and the fan rotation speed. A table as shown in FIG. 9 is stored in advance in a memory (not shown), and the fan rotation speed is obtained based on the estimated temperature Tccn of the capacity adjustment circuit. And the cooling fan 50 is controlled so that the rotation speed of the cooling fan 50 may correspond with the calculated | required fan rotation speed.

  On the other hand, if it is determined in step S200 that the estimated temperature Tccn of the capacity adjustment circuit is 70 ° C. or less, the process proceeds to step S220. In step S220, it is determined whether or not the temperature of the assembled battery 100 detected by the temperature sensor 20 is lower than a second predetermined temperature of 20 ° C. If it determines with the temperature of the assembled battery 100 being lower than 20 degreeC, it will progress to step S230. In step S230, the rotation speed of the cooling fan 50 is controlled based on the temperature of the assembled battery 100. FIG. 10 is a diagram showing the relationship between the temperature of the assembled battery 100 and the rotational speed of the cooling fan 50. A table as shown in FIG. 10 is stored in advance in a memory (not shown), and the fan rotation speed is obtained based on the temperature of the assembled battery 100 detected by the temperature sensor 20. And the cooling fan 50 is controlled so that the rotation speed of the cooling fan 50 may correspond with the calculated | required fan rotation speed.

  On the other hand, if it determines with the temperature of the assembled battery 100 being 20 degreeC or more in step S220, it will progress to step S240. In step S240, it is determined whether or not the estimated temperature Tccn of the capacity adjustment circuit is higher than a third predetermined temperature 40 ° C. If it is determined that the estimated temperature Tccn of the capacity adjustment circuit is higher than 40 ° C., the process proceeds to step S260. In step S260, the fan speed determined based on the estimated temperature Tccn of the capacity adjustment circuit with reference to the table shown in FIG. 9 and the temperature of the battery pack 100 determined based on the table shown in FIG. The higher fan speed is selected and the cooling fan 50 is controlled so that the rotational speed of the cooling fan 50 matches the selected fan speed.

  On the other hand, if it is determined in step S240 that the estimated temperature Tccn of the capacity adjustment circuit is 40 ° C. or less, the process proceeds to step S250. In step S250, the same process as the process performed in step S230, that is, the fan rotation speed is determined based on the temperature of the assembled battery 100, and cooling is performed so that the rotation speed of the cooling fan 50 matches the determined fan rotation speed. Processing for controlling the fan 50 is performed. If the process which controls the rotation speed of the cooling fan 50 is performed, it will progress to step S100 of the flowchart shown in FIG.

  In step S100, a signal for turning on the switch provided corresponding to the cell for which the bypass adjustment amount is determined to be larger than 0 is transmitted to the cell controller managing the corresponding cell. On the other hand, in step S110 that proceeds after it is determined that the bypass adjustment amount is 0 or less, a signal for turning off the switch provided corresponding to the cell that is determined that the bypass adjustment amount is 0 or less is sent to the corresponding cell. To the cell controller that manages

  In step S3, the cell controllers CC1 to CCt determine whether or not a signal for turning on / off the switches S1 to Sn is received from the battery controller 30. If it is determined that a signal for turning on / off the switches S1 to Sn is not received, the process waits in step S3. If it is determined that the signal is received, the process proceeds to step S4. In step S4, the switches S1 to Sn are turned on / off based on the received signal. For example, when the cell controller CC1 receives a signal for turning on the switch S2, the cell C2 is discharged by turning on the switch S2.

  When the battery controller 30 performs the process of step S100 or step S110, the process proceeds to step S120. In step S120, it is determined whether or not the bypass adjustment amounts of all the cells C1 to Cn have become zero. If it is determined that the bypass adjustment amount of all the cells is 0, the capacity adjustment process between the cells is terminated. On the other hand, if it is determined that at least one of the bypass adjustment amounts is not 0, the process returns to step S30 to perform processing for calculating the bypass adjustment amount. When the process returns from step S100 to step S30, the bypass adjustment amount is obtained by the above equation (1). Thereafter, the processing from step S30 to step S120 is repeatedly performed until the bypass adjustment amount of all the cells becomes zero.

  According to the assembled battery cooling device in the first embodiment, when the temperature of the capacity adjustment circuit is higher than the first predetermined temperature of 70 ° C., the cooling fan 50 is adjusted based on the temperature of the capacity adjustment circuit. Therefore, when the temperature of the capacity adjustment circuit increases, the capacity adjustment circuit can be effectively cooled regardless of the temperature of the assembled battery 100.

  In addition, according to the battery pack cooling apparatus in the first embodiment, the temperature of the capacity adjustment circuit is 70 ° C. or less, which is the first predetermined temperature, and the temperature of the battery pack 100 is the second temperature. When the temperature is lower than 20 ° C., the cooling fan 50 is controlled based on the temperature of the assembled battery 100, so that the temperature of the assembled battery 100 can be prevented from excessively decreasing.

  Furthermore, according to the battery pack cooling apparatus in the first embodiment, the temperature of the capacity adjustment circuit is not higher than 70 ° C. which is the first predetermined temperature, but is higher than 40 ° C. which is the third temperature, and When the temperature of the assembled battery 100 is equal to or higher than 20 ° C., which is the second temperature, out of the fan rotational speed determined based on the temperature of the capacity adjustment circuit and the fan rotational speed determined based on the temperature of the assembled battery 100 The cooling fan 50 is controlled on the basis of the higher fan speed. Thereby, it is possible to perform appropriate cooling control in consideration of both the capacity adjustment circuit and the state of the assembled battery 100.

  According to the assembled battery cooling device of the first embodiment, the temperature of the capacity adjustment circuit rises due to the ambient temperature of the capacity adjustment circuit and the amount of heat generated during capacity adjustment (cell discharge) in the capacity adjustment circuit. Since the temperature of the capacity adjustment circuit is estimated based on the amount, there is no need to provide a temperature sensor for detecting the temperature of the capacity adjustment circuit. Thereby, the cost of the whole circuit can be reduced.

-Second Embodiment-
The configuration of the assembled battery cooling device in the second embodiment is the same as the configuration of the assembled battery cooling device in the first embodiment shown in FIG. The battery pack cooling device in the second embodiment differs from the battery pack cooling device in the first embodiment in the location of the battery controller 30 and the cell controllers CC1 to CCt.

  FIG. 11 is a diagram illustrating a positional relationship among the cooling fan 50, the battery controller 30, the cell controllers CC <b> 1 to CCt, and the assembled battery 100. As shown in FIG. 11, the integrated battery controller 30 and cell controllers CC <b> 1 to CCt are arranged in contact with the assembled battery 100.

  The process performed by the assembled battery cooling device in the second embodiment is the same as the process performed by the assembled battery cooling device in the first embodiment. However, in step S80 of the flowchart shown in FIG. 5, the method for obtaining the ambient temperature T of the capacity adjustment circuit necessary for obtaining the estimated temperature Tccn of the capacity adjustment circuit is different. Hereinafter, a method of obtaining the ambient temperature T of the capacity adjustment circuit according to whether the temperature sensor 20 is abnormal will be described.

= When temperature sensor is normal =
Regardless of the operation of the cooling fan, the ambient temperature T of the capacity adjustment circuit can be approximated by the temperature of the assembled battery 100. Therefore, when the temperature sensor 20 is normal, the temperature detected by the temperature sensor 20 is used as the ambient temperature T.

= When temperature sensor is abnormal =
When an abnormality has occurred in the temperature sensor 20, the ambient temperature T is estimated based on the temperature in the passenger compartment and the SOC of the assembled battery 100. The temperature in the passenger compartment can be acquired from an air conditioner controller (not shown). Further, the SOC of the assembled battery 100 can be obtained by a known calculation method. FIG. 12 is a diagram illustrating the relationship between the temperature in the vehicle compartment, the SOC of the assembled battery 100, and the temperature of the assembled battery 100. The temperature in the vehicle compartment and the temperature of the assembled battery corresponding to the SOC of the assembled battery 100 are obtained in advance by experiments or the like, and a table as shown in FIG. 12 is prepared and stored in a memory (not shown). The battery controller 30 obtains the temperature of the assembled battery 100 by referring to the table shown in FIG. 12 based on the temperature in the vehicle compartment and the SOC of the assembled battery 100. As described above, since the ambient temperature T of the capacity adjustment circuit can be approximated by the temperature of the assembled battery 100, the obtained temperature of the assembled battery 100 is used as the ambient temperature T.

  Also in the assembled battery cooling device in the second embodiment, the capacity adjustment circuit can be effectively cooled, as in the assembled battery cooling device in the first embodiment.

  The present invention is not limited to the embodiments described above. For example, although the battery controller 30 performs the calculation of the time average voltage for each cell and the calculation of the bypass adjustment amounts Cct1 to Cctn, the cell controllers CC1 to CCt may perform the calculation.

  Although the temperature of the capacity adjustment circuit has been described as being estimated from Equation (5), it may be estimated by a method other than Equation (5). In Equation (5), the ambient temperature T of the capacity adjustment circuit is approximated by the temperature of the assembled battery 100, or approximated by the vehicle interior temperature or the vehicle exterior temperature, but a temperature sensor is provided in the vicinity of the capacity adjustment circuit. A value detected by a temperature sensor may be used. Further, a temperature sensor may be provided in the capacity adjustment circuit without directly estimating the temperature of the capacity adjustment circuit, and the temperature may be directly detected.

  When an abnormality occurs in the cooling fan 50, temperature rises in the assembled battery 100 and the capacity adjustment circuit can be suppressed by limiting the charge / discharge amount of the cell. For example, even if charging / discharging of the assembled battery 100 is performed in a state where the cooling fan 50 is stopped, a charge / discharge amount that does not increase to a temperature at which the assembled battery 100 deteriorates (for example, 60 ° C.) is previously determined for each vehicle interior temperature by experiments or the like. I ask for it. FIG. 13 is a table showing the relationship between the vehicle interior temperature and the charge / discharge amount that does not rise to a temperature at which the assembled battery 100 deteriorates even if the assembled battery 100 is charged / discharged in a state where the cooling fan 50 is stopped. Based on the vehicle interior temperature obtained from an air conditioner controller (not shown) and the table shown in FIG. 13, the chargeable / dischargeable amount is obtained, and the charge / discharge amount of the assembled battery 100 is limited. Even when this occurs, the temperature rise of the assembled battery 100 and the capacity adjustment circuit can be suppressed. Similarly, when the temperature of the assembled battery 100 rises to a predetermined temperature or higher, control for limiting the charge / discharge amount is started, and when the temperature of the assembled battery 100 rises to 60 ° C. or higher, the charge / discharge amount becomes zero. You may make it restrict | limit.

  In addition, when an abnormality occurs in the cooling fan 50, the number of cells whose capacity is adjusted can be limited. For example, the temperature (estimated temperature) of the capacity adjustment circuit when the number of cells for capacity adjustment is limited is calculated (see Equation (5)), and the calculated temperature of the capacity adjustment circuit is a predetermined temperature (for example, the cell controller The number of cells that are equal to or lower than the guaranteed operating temperature) is obtained, and the capacity adjustment is performed by the obtained number of cells preferentially from the cells having large capacity variations. Thereby, even when abnormality occurs in the cooling fan 50, the temperature rise of the assembled battery 100 and the capacity adjustment circuit can be suppressed. If the temperature of the capacity adjustment circuit exceeds a predetermined temperature even if the number of cells is limited, the capacity adjustment may be temporarily stopped.

  In the flowchart shown in FIG. 6, the first predetermined temperature and the third predetermined temperature to be compared with the estimated temperature Tccn of the capacity adjustment circuit are 70 ° C. and 40 ° C., respectively, but are limited to these temperatures. Rather, an appropriate value may be set based on the configuration of the capacity adjustment circuit (cell controller). Similarly, the value of the second predetermined temperature compared with the temperature of the assembled battery 100 is not limited to 20 ° C.

  In the flowchart shown in FIG. 6, the cooling fan 50 is controlled based on the estimated temperature Tccn of the capacity adjustment circuit and the temperature of the assembled battery 100, but based on the temperature of the assembled battery 100 during normal control. The fan control may be performed so that the fan control based on the temperature of the assembled battery 100 is temporarily stopped based on the estimated temperature Tccn of the capacity adjustment circuit. That is, when the estimated temperature Tccn of the capacity adjustment circuit exceeds 70 ° C., switching to fan control based on the estimated temperature Tccn of the capacity adjustment circuit, or the estimated temperature Tccn of the capacity adjustment circuit is higher than 40 ° C. but lower than 70 ° C. And when the temperature of the assembled battery 100 is 20 degreeC or more, it can be set as the system switched to the control (step S260) which selects the higher fan rotation speed.

  In each of the above-described embodiments, an example in which the assembled battery cooling device is applied to a hybrid vehicle has been described. The capacity adjustment of each of the cells C1 to Cn can be performed even when the vehicle is keyed off. However, if various calculations are performed every predetermined time, the battery power consumption at the time of keyoff increases. Therefore, a clock generation circuit is provided in the circuit, and various operations are performed based on the operation clock signal generated by the clock generation circuit. When the vehicle is keyed off, the operation clock signal generation interval is lengthened to reduce power consumption. May be reduced. In addition, the generation timing of the operation clock signal generated by each cell controller CC1 to CCt by the clock generation circuit can be controlled. In this case, each cell controller CC1 to CCt may increase the generation interval of the operation clock signal generated by the clock generation circuit when the vehicle is keyed off.

  Although a lithium ion battery has been described as an example of the assembled battery 100, the present invention is not limited by the type of the assembled battery. For example, the assembled battery may be a nickel metal hydride battery or a lead acid battery.

  In each of the above-described embodiments, the example in which the assembled battery cooling device is applied to a hybrid vehicle has been described. However, the embodiment can be applied to an electric vehicle or a system other than an automobile.

  The correspondence between the constituent elements of the claims and the constituent elements of the first and second embodiments is as follows. That is, the battery controller 30 includes first temperature acquisition means, control means, first cooling degree determination means, second cooling degree determination means, ambient temperature acquisition means, temperature increase acquisition means, failure detection means, charge / discharge amount. The limiting means and the cell number changing means, the cooling fan 50 constitutes the cooling means, and the temperature sensor 20 constitutes the second temperature acquisition means. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

The figure which shows the structure of the cooling device of the assembled battery in 1st Embodiment. The figure which shows the positional relationship of a cooling fan, a battery controller, a cell controller, and an assembled battery Diagram showing detailed circuit configuration of cell controller Diagram for determining the amount of bypass adjustment from the open circuit voltage and capacity adjustment target voltage of each cell The flowchart which shows the processing content performed with the cooling device of the assembled battery in 1st Embodiment. Flow chart showing detailed contents of fan control FIG. 7A is a diagram of the cell controller viewed from the lateral direction, and FIG. 7B is a diagram of the cell controller viewed from the front (rear). A table showing the relationship between the discharge amount of the cell during capacity adjustment, the flow velocity of the cooling passage, and ΔTup in the steady state Diagram showing the relationship between estimated temperature of capacity adjustment circuit and fan speed The figure which shows the relationship between the temperature of an assembled battery and the rotation speed of a cooling fan The figure which shows the positional relationship of a cooling fan, a battery controller, a cell controller, and an assembled battery in the cooling device of the assembled battery in 2nd Embodiment. The figure which shows the relationship between the temperature of a vehicle interior, SOC of an assembled battery, and the temperature of an assembled battery The figure which shows the relationship between vehicle interior temperature and the amount of charging / discharging which does not rise to the temperature which an assembled battery deteriorates, even if it performs charging / discharging of an assembled battery in the state which the cooling fan stopped

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Total voltage sensor, 11 ... IC, 12 ... A / D converter, 13 ... Interface (IF), 14 ... Photocoupler, 20 ... Temperature sensor, 30 ... Battery controller, 50 ... Cooling fan, 60 ... Cooling passage, 100 ... Battery, R1-Rn ... Resistor, S1-Sn ... Switch

Claims (8)

In order to make the capacity of a plurality of cells constituting the assembled battery uniform, discharging means for discharging each cell,
First temperature acquisition means for acquiring the temperature of the discharge means;
Cooling means for cooling at least the assembled battery and the discharging means;
Control means for controlling the cooling means based on the temperature of the discharge means when the temperature of the discharge means acquired by the first temperature acquisition means is higher than a first predetermined temperature. A battery pack cooling device. The battery pack cooling device according to claim 1,
A second temperature acquisition means for acquiring the temperature of the assembled battery;
The control means is configured such that the temperature of the discharge means acquired by the first temperature acquisition means is equal to or lower than a first predetermined temperature, and the temperature of the assembled battery acquired by the second temperature acquisition means is second. When the temperature is lower than the predetermined temperature, the cooling unit is controlled based on the temperature of the assembled battery. The battery pack cooling device according to claim 2,
First cooling degree determination means for determining a cooling degree of the cooling means based on the temperature of the discharging means;
A second cooling degree determining means for determining a cooling degree of the cooling means based on the temperature of the assembled battery,
The control means is configured such that the temperature of the discharge means acquired by the first temperature acquisition means is equal to or lower than the first predetermined temperature but is higher than a third predetermined temperature and is set by the second temperature acquisition means. When the temperature of the battery pack to be acquired is equal to or higher than the second predetermined temperature, the cooling degree determined by the first cooling degree determining means and the second cooling degree determining means are determined. A cooling device for an assembled battery, wherein the cooling means is controlled based on a cooling degree having a higher cooling degree among the cooling degrees. The battery pack cooling device according to claim 3,
The control means is configured such that the temperature of the discharge means acquired by the first temperature acquisition means is equal to or lower than the third predetermined temperature, and the temperature of the assembled battery acquired by the second temperature acquisition means is When the temperature is equal to or higher than the second predetermined temperature, the cooling device for the assembled battery controls the cooling means based on the temperature of the assembled battery. In the assembled battery cooling device according to any one of claims 1 to 4,
Ambient temperature acquisition means for determining the ambient temperature of the discharge means;
A temperature rise amount obtaining means for obtaining a temperature rise amount of the discharge means due to the amount of heat generated when the cells are discharged by the discharge means;
The first temperature acquisition means estimates the temperature of the discharge means based on the ambient temperature of the discharge means determined by the ambient temperature acquisition means and the temperature increase amount determined by the temperature increase amount acquisition means. An assembled battery cooling device. In the assembled battery cooling device according to any one of claims 2 to 5,
The battery pack further comprising charge / discharge amount limiting means for limiting the charge / discharge amount of the battery pack when the temperature of the battery pack acquired by the second temperature acquisition device is equal to or higher than a fourth predetermined temperature. Battery cooling device. In the assembled battery cooling device according to any one of claims 1 to 5,
A failure detection means for detecting a failure of the cooling means;
An assembled battery cooling device, further comprising charge / discharge amount limiting means for restricting a charge / discharge amount of the assembled battery when a failure of the cooling means is detected by the failure detection means. The assembled battery cooling device according to any one of claims 1 to 6,
A failure detection means for detecting a failure of the cooling means;
An assembled battery cooling device, further comprising capacity adjustment cell number changing means for reducing the number of cells for capacity adjustment when the failure detection means detects a failure of the cooling means.

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