JP2016146279A - Air conditioning controller of battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature controller of a battery pack, capable of suppressing problems due to adhesion of dew condensation to the metal terminal of a secondary battery in a battery pack housing the secondary battery and a cooler.SOLUTION: An air conditioning controller of a battery pack, mounted on a vehicle, and performing air conditioning control in a battery pack housing a secondary battery for supplying power to a motor as a drive source and a cooler for cooling the secondary battery, includes a dew condensation occurrence temperature calculation unit for calculating the dew condensation occurrence temperature on the basis of the temperature and humidity of air in the battery pack, a dew condensation prevention control execution determination unit for determining whether or not the mount of water vapor in the battery pack is copious, and a dew condensation prevention control unit for controlling the cooler so that the temperature of air in the battery pack is maintained higher than the dew condensation occurrence temperature, when a determination is made that the mount of water vapor is copious.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an air conditioning control device for a battery pack, and more particularly to an air conditioning control device for a battery pack that is mounted on a vehicle and performs air conditioning control in a battery pack that houses a secondary battery.

  2. Description of the Related Art In recent years, an electric vehicle or a hybrid vehicle including an electric motor that outputs a driving force of the vehicle and a secondary battery that can be charged by an in-vehicle power generation device or an external charging device is known. The secondary battery provided in such a vehicle is accommodated in a case so that it can withstand erosion by water and impact from the outside. In addition to the secondary battery, there is a battery pack in which a cooling device for cooling the secondary battery is housed in a case. If moisture enters the battery pack, the battery pack's inner wall and metal terminals may be corroded, leaked, or short-circuited. Therefore, the battery pack is usually sealed with sealing parts such as gaskets and packing, The air humidity is kept low.

  Here, Patent Document 1 proposes a temperature control device for a secondary battery for preventing condensed water generated by an evaporator as a cooling device housed in the battery pack from reaching the electrode of the secondary battery. Has been. Such a temperature control apparatus has a blower, a fin member, and a duct on the downstream side of the evaporator, and fine granular condensed water sent from the evaporator is blocked by adhering to the blower and the fin member and evaporating. Moreover, in this temperature control apparatus, the distance from an evaporator to an electrode is ensured and it is difficult for condensed water to reach an electrode.

International Publication No. 2014/069270

  The temperature control device described in Patent Document 1 supplies the refrigerant to the evaporator and starts cooling control when the temperature in the battery pack becomes higher than the first set temperature. In addition, such a temperature control device operates the PTC heater to raise the temperature when the temperature inside the battery pack falls below the second set temperature. The temperature control device of Patent Document 1 is a device for evaporating condensed water generated by an evaporator on a blower or a fin member while performing normal cooling control of a secondary battery.

  However, when the sealing performance of the battery pack is reduced due to deterioration of the sealing parts and the case, or when outside air flows into the battery pack, external moist air gradually enters the battery pack, The humidity of the air in the battery pack increases. When the humidity of the air in the pack is high, the temperature at which condensation occurs is also high, and the metal part in the battery pack other than the evaporator is likely to be condensed. If it does so, there exists a possibility that the generated dew condensation may adhere to a metal terminal by the air and vibration which circulate in the inside of a pack. Therefore, it is desirable to prevent water droplets from adhering to the metal terminals of the secondary battery even when the humidity of the air in the battery pack increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to form condensation on the metal terminals of the secondary battery in the battery pack in which the secondary battery and the cooling device are accommodated. An object of the present invention is to provide a temperature control device for a battery pack that can suppress problems caused by the above.

  In order to solve the above problems, according to an aspect of the present invention, a secondary battery mounted on a vehicle and supplying electric power to an electric motor as a drive source and a cooling device for cooling the secondary battery are accommodated. In the battery pack air-conditioning control apparatus for performing air-conditioning control in the battery pack, the condensation generation temperature calculation unit for calculating the condensation generation temperature based on the temperature and humidity of the air in the battery pack, and the inside of the battery pack A dew condensation prevention control execution determination unit that determines whether or not the amount of water vapor in the air is large, and when it is determined that the amount of water vapor is large, the temperature of the air in the battery pack is higher than the dew condensation occurrence temperature. And a dew condensation prevention control unit that controls the cooling device so as to be maintained at a high level.

  The cooling device includes an evaporator and an electric expansion valve that adjusts a refrigerant injection amount to the evaporator, and the dew condensation prevention control unit is based on information related to a heat generation amount of the secondary battery and the dew condensation generation temperature. The opening of the electric expansion valve may be set.

  The dew condensation prevention control unit may control the cooling device with an output capable of canceling a calorific value of the secondary battery.

  When the temperature of the air in the battery pack becomes equal to or higher than a stop reference value that is higher than the temperature of the secondary battery at the start of the condensation prevention control, the condensation prevention control unit You may complete | finish the control which maintains the temperature of air higher than the said dew condensation generation temperature.

  There may be provided a calorific value calculation unit for calculating a calorific value of the secondary battery based on at least one of a running load of the vehicle, a required power to the secondary battery, and a temperature change of the secondary battery. .

  The dew condensation prevention control execution determination unit may determine whether the amount of water vapor is large based on the temperature and humidity of the air in the battery pack.

  According to the air conditioning control device for a battery pack according to the present invention, it is possible to suppress problems caused by condensation on the metal terminals of the secondary battery in the battery pack in which the secondary battery and the cooling device are accommodated.

It is a schematic diagram which shows schematic structure of the air conditioner of the battery pack concerning one Embodiment of this invention. It is a block diagram which shows the structural example of the air-conditioning control apparatus of a battery pack. It is a characteristic view which shows the relationship between the required electric energy of a secondary battery, and the amount of self-heating. It is a characteristic view which shows the relationship between the refrigerant | coolant injection amount to an evaporator, and the fall amount of the air temperature in a pack. It is a characteristic view which shows the relationship between the variation | change_quantity of an accelerator operation amount, and the refrigerant | coolant injection amount to an evaporator. It is a flowchart which shows the air-conditioning control method of a battery pack. It is a flowchart which shows normal cooling control. It is a flowchart which shows condensation prevention control. It is a time chart which shows transition of the temperature inside a battery pack at the time of performing only normal cooling control. It is a time chart which shows transition of the temperature inside a battery pack at the time of performing dew condensation prevention control.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<< 1. Example of overall configuration of battery pack air conditioner >>
First, an example of the whole structure of the air conditioner of the battery pack concerning one Embodiment of this invention is demonstrated. FIG. 1 is a schematic diagram illustrating a configuration example of the air conditioner 10 of the battery pack 20 according to the present embodiment. The air conditioner 10 of the battery pack 20 is mounted on an electric vehicle (EV) or a hybrid vehicle (HEV), and performs air conditioning in the battery pack 20 for supplying electric power to an electric motor as a drive source of the vehicle. Device.

  The air conditioner 10 includes a battery pack 20 to be air-conditioned, a blower fan 24, various sensors 25, 26, 27, 28, a cooling device 30, and a heater 29. In addition, the air conditioner 10 includes an air conditioner control apparatus 100 that performs air conditioning control. Although the air-conditioning control apparatus 100 shown in FIG. 1 is provided outside the case 21, it may be placed in the case 21 in an airtightly sealed state.

<1-1. Case>
The battery pack 20 includes a case 21 in which the secondary battery 22 is accommodated. In the present embodiment, an evaporator 31 that is a component of the blower fan 24, the cooling device 30, and the heater 29 is accommodated in the case 21. The case 21 can be a metal case excellent in durability and strength, but is not limited thereto, and may be a case made of other materials such as a resin. The case 21 is sealed using seal parts such as a gasket, packing, and O-ring in a state where the secondary battery 22 and the evaporator 31 are accommodated.

  The case 21 is connected to a duct 18 serving as an internal air circulation passage. The duct 18 shown in FIG. 1 is shown separated from the case 21, but the configuration of the duct 18 is not limited to this example. For example, a duct 18 that circulates air may be configured by partitioning a space in the case 21.

<1-2. Secondary battery>
The battery pack 20 houses the secondary battery 22 in the case 21. The secondary battery 22 is a high voltage battery that supplies electric power to an electric motor (not shown), and can be charged by a power generator (not shown). The secondary battery 22 may be capable of supplying power to other electrical devices other than the electric motor. The secondary battery 22 is typically exemplified by a lithium ion battery, but may be constituted by other secondary batteries. Although the secondary battery 22 shown in FIG. 1 is a cylindrical battery, the secondary battery 22 may be box-shaped, and the shape is not particularly limited. Further, the number of secondary batteries 22 accommodated in the case 21 is not particularly limited.

  The secondary battery 22 generates heat during charging / discharging. In particular, when the amount of charge / discharge is large, the amount of heat generation also increases. On the other hand, it is known that the secondary battery 22 easily deteriorates at high temperatures and low temperatures. Therefore, the battery pack 20 is provided with a cooling device 30 so that the secondary battery 22 is controlled to be cooled so that the temperature of the secondary battery 22 is maintained at a target management temperature that is an appropriate temperature. ing.

<1-3. Blower fan>
The blower fan 24 is driven by, for example, an electric motor (not shown), and circulates the air in the battery pack 20. The electric motor of the blower fan 24 is controlled by the air conditioning control device 100. The blower fan 24 is provided on the upstream side of the evaporator 31 and the secondary battery 22, and sends air to the evaporator 31, and sends air cooled by the evaporator 31 by heat exchange to the secondary battery 22. The air sent to the secondary battery 22 by the blower fan 24 returns to the upstream side of the blower fan 24 again through the duct 18 connected to the case 21.

<1-4. Sensors>
The battery pack 20 includes a first temperature sensor 25 that detects the temperature of the secondary battery 22 (hereinafter also referred to as “battery temperature”) and the temperature of the air in the battery pack 20 (hereinafter referred to as “pack air temperature”). Also, the second temperature sensor 26 that detects the temperature of the evaporator 31, the third temperature sensor 27 that detects the temperature of the surface of the evaporator 31, and the humidity of the air in the battery pack 20 (hereinafter also referred to as “in-pack humidity”). ) To detect the humidity sensor 28. Detection information of the first temperature sensor 25, the second temperature sensor 26, the third temperature sensor 27, and the humidity sensor 28 is sent to the air conditioning control device 100.

  The first temperature sensor 25 is provided on the surface of the secondary battery 22, for example, and detects the temperature of the surface of the secondary battery 22. As the first temperature sensor 25, for example, a thermocouple can be used, but other temperature sensors may be used. In FIG. 1, one first temperature sensor 25 is shown. However, a plurality of first temperature sensors 25 may be provided, or each secondary battery 22 may be provided.

  The second temperature sensor 26 is provided, for example, on the inner wall of the case 21 and detects the air temperature in the pack. As the second temperature sensor 26, for example, a thermocouple can be used, but other temperature sensors may be used. In FIG. 1, one second temperature sensor 26 is shown, but a plurality of second temperature sensors 26 may be provided. When a plurality of second temperature sensors 26 are provided, each second temperature sensor 26 may detect the temperature at a different position in the case 21.

  The third temperature sensor 27 is provided at any position on the surface of the evaporator 31 and detects the temperature of the surface of the evaporator 31. As the third temperature sensor 27, for example, a thermocouple can be used, but other temperature sensors may be used. A plurality of third temperature sensors 27 may be provided. However, the temperature of the surface of the evaporator 31 is not limited to the position and is relatively uniform.

  The humidity sensor 28 is provided, for example, on the inner wall of the case 21 and detects the humidity in the pack. The humidity sensor is not particularly limited, and a known humidity sensor can be used. In FIG. 1, one humidity sensor 28 is shown, but a plurality of humidity sensors 28 may be provided. When a plurality of humidity sensors 28 are provided, each humidity sensor 28 may detect humidity at different positions in the case 21.

<1-5. Cooling device>
The cooling device 30 includes an evaporator 31, a refrigerant circulation passage 33 that circulates the refrigerant supplied to the evaporator 31, an expansion valve 32 that adjusts the injection amount of the refrigerant to the evaporator 31, and a cooling medium for cooling the circulating refrigerant. And a cooling unit 34. The cooling unit 34 includes a compressor, a condenser, and a receiver tank.

  In the cooling unit 34, the refrigerant is liquefied and cooled. Briefly, in the cooling unit 34, the high-temperature and high-pressure semi-liquid refrigerant compressed by the compressor is cooled in the condenser and liquefied, and then sent to the receiver tank. In the receiver tank, the refrigerant that has not been liquefied is separated from the liquid refrigerant, and moisture and impurities are removed from the refrigerant by a desiccant, a strainer, and the like. Then, the liquefied and cooled refrigerant in the cooling unit 34 is sent from the cooling unit 34 to the expansion valve 32. The cooling unit 34 is controlled by the air conditioning control device 100.

  The expansion valve 32 injects the refrigerant from the minute nozzle holes, vaporizes the liquid refrigerant, and supplies it to the evaporator 31. In the present embodiment, an electric expansion valve that can adjust the injection amount of the refrigerant is used as the expansion valve 32. The electric expansion valve includes, for example, an electromagnetic valve that can adjust the passage area of the refrigerant on the upstream side of the nozzle hole. The expansion valve 32 is controlled by the air conditioning control device 100. However, the expansion valve 32 is not limited to the above example, and may be any valve that can adjust the injection amount of the refrigerant.

  The refrigerant injected and vaporized from the expansion valve 32 removes the heat around the evaporator 31 when passing through the evaporator 31, thereby lowering the temperature of the evaporator 31. Cold air is sent to the secondary battery 22 by allowing the air circulated by the blower fan 24 to pass through the evaporator 31. At this time, if the humidity in the pack is high, the air is cooled on the surface of the evaporator 31, moisture in the air is condensed, and water droplets are generated. The refrigerant that has passed through the evaporator 31 is returned to the cooling unit 34 and compressed.

  In addition, the battery pack 20 of this embodiment is not provided with the drain pipe or drainage means for discharging the liquefied water in the battery pack 20 out of the case 21. Therefore, moisture does not easily enter the battery pack 20 when the vehicle is traveling, etc., except when moist air or moisture enters the case 21 due to deterioration of the case 21 or seal parts.

<1-6. Heater>
The heater 29 is a device for raising the temperature inside the battery pack 20. In the present embodiment, a PTC heater is provided between the blower fan 24 and the evaporator 31. By operating the blower fan 24 in a state where the heater 29 is operated, the temperature in the battery pack 20 is increased. However, the arrangement position of the heater 29 is not limited to this example. Further, whether or not to operate the blower fan 24 when the heater 29 is operated can be appropriately set depending on the size and shape of the battery pack 20.

<< 2. Air-conditioning control device >>
Next, the air conditioning control device 100 that controls the air conditioning device 10 will be described. FIG. 2 is a block diagram functionally showing the configuration of the air conditioning control device 100 according to the present embodiment. The air conditioning control device 100 includes a known microcomputer.

  The air conditioning control device 100 includes a dew condensation prevention control execution determination unit 102, a dew condensation prevention control unit 104, a heater control unit 106, a blower fan control unit 108, an expansion valve control unit 110, and a cooling auxiliary device control unit 112. A cooling control unit 114, a dew condensation temperature calculation unit 116, and a heat generation amount calculation unit 118. Specifically, each of these units can be realized by executing a program by the microcomputer. In addition, the air conditioning control device 100 includes a blower fan drive circuit, an expansion valve drive circuit, and a cooling auxiliary device drive circuit.

  Further, the air conditioning control device 100 includes a storage element (not shown) such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The air conditioning control device 100 detects the battery temperature Tba information detected by the first temperature sensor 25, the pack air temperature Tbp information detected by the second temperature sensor 26, and the third temperature sensor 27. Information on the temperature Tev on the surface of the evaporator 31 and the humidity Hbp in the pack detected by the humidity sensor 28 can be read.

  The blower fan control unit 108, the expansion valve control unit 110, and the cooling auxiliary device control unit 112 are arranged in the normal cooling control according to the control amount instructed from the cooling control unit 114. Drive commands are output to the valve drive circuit and the cooling accessory drive circuit, respectively. Further, the heater control unit 106, the blower fan control unit 108, the expansion valve control unit 110, and the cooling auxiliary device control unit 112, according to the control amount instructed from the dew condensation prevention control unit 104 during the dew condensation prevention control, Drive commands are output to the heater drive circuit, the blower fan drive circuit, the expansion valve drive circuit, and the cooling auxiliary device drive circuit, respectively.

  However, in the air-conditioning control apparatus 100 according to the present embodiment, the supply of electric power to the heater 29, the blower fan 24, and the cooling unit 34 only needs to be able to be switched on or off. Variable control is not essential.

<2-1. Cooling control unit>
The cooling control unit 114 reads the battery temperature Tba detected by the first temperature sensor 25, and when the battery temperature Tba is higher than the target management temperature Tba_tgt, the battery temperature Tba becomes the target management temperature Tba_tgt. The normal cooling control in the battery pack 20 is executed using the cooling device 30. When a plurality of first temperature sensors 25 are provided, the battery temperature Tba used for the determination may be the lowest value of the detected battery temperatures Tba, or the average value of the detected battery temperatures Tba. It is good.

  As described above, it is known that the secondary battery 22 easily deteriorates at high temperatures and low temperatures. Therefore, the cooling control unit 114 controls the cooling device 30 so that the battery temperature Tba is maintained near the target management temperature Tba_tgt. The target management temperature Tba_tgt can be set to 40 to 45 ° C., for example. The cooling control unit 114 instructs the control amount to the expansion valve control unit 110 and the cooling auxiliary device control unit 112 so that the injection amount of the refrigerant gradually increases. For example, when the battery temperature Tba is higher than the target management temperature Tba_tgt, the cooling control unit 114 cools the secondary battery 22 by gradually cooling the evaporator 31 while operating the blower fan 24. The output of the blower fan 24 may be variable.

  In such normal cooling control, the amount of refrigerant injected from the expansion valve 32 to the evaporator 31 is gradually increased while monitoring whether or not the battery temperature Tba reaches the target management temperature Tba_tgt. If the injection amount of the refrigerant to the evaporator 31 is suddenly increased, the battery temperature Tba suddenly decreases and greatly falls below the target management temperature Tba_tgt, and the normal cooling control is repeatedly executed and stopped, so that the battery temperature Tba may not be stabilized. Because there is.

  In the present embodiment, the cooling control unit 114 reads the temperature Tev on the surface of the evaporator 31 detected by the third temperature sensor 27 every predetermined cycle, and sends it to the evaporator 31 according to the amount of decrease in the temperature Tev in the predetermined cycle. The amount of refrigerant injected is determined. Thereby, the decreasing speed of the temperature Tev on the surface of the evaporator 31 is controlled so as not to exceed a predetermined speed.

<2-2. Dew condensation prevention control execution determination unit>
The dew condensation prevention control execution determination unit 102 determines whether or not the amount of water vapor in the air in the battery pack 20 is large. The dew condensation prevention control execution determination unit 102 determines whether the in-pack humidity Hbp is equal to or higher than a predetermined start reference value Hbp_str, so that the inside of the battery pack 20 can It is determined whether or not the humidity is high, and it is determined whether or not the dew condensation prevention control is necessary. The saturated water vapor amount of water increases as the temperature increases. Therefore, even if the amount of water vapor contained in the air is the same, the higher the temperature, the lower the humidity, so the start reference value Hbp_str can be a variable value that depends on the in-pack air temperature Tbp.

  Therefore, in this embodiment, the dew condensation prevention control execution determination unit 102 reads the in-pack air temperature Tbp and the in-pack humidity Hbp, and the start reference value Hbp_str determined according to the in-pack air temperature Tbp and the in-pack humidity Hbp. And compare. The dew condensation prevention control execution determination unit 102 determines that the dew condensation prevention control is necessary when the in-pack humidity Hbp is equal to or higher than the start reference value Hbp_str. The start reference value Hbp_str depending on the in-pack air temperature Tbp can be set to a value corresponding to 100% humidity when the air temperature is 15 ° C., for example.

  In addition to the determination of the in-pack humidity Hbp, the dew condensation prevention control execution determination unit 102 determines whether the in-pack air temperature Tbp is equal to or lower than the upper limit value Tbp_str_max, and determines whether or not the dew condensation prevention control is necessary. May be. This is because when the pack air temperature Tbp is high, even if the cooling device 30 is operated, the metal part in the battery pack 20 is less likely to be below the temperature at which condensation occurs, and the need for condensation prevention control is low. . The upper limit value Tbp_str_max can be set to 40 ° C., for example.

  When a plurality of humidity sensors 28 are provided, the in-pack humidity Hbp used for the determination may be the highest value of the detected in-pack humidity Hbp, or the average value of the detected in-pack humidity Hbp. Also good. When a plurality of second temperature sensors 26 are provided, the pack air temperature Tbp used for determination may be the highest value or the lowest value of the detected pack air temperatures Tbp, or may be detected. It is good also as an average value of battery temperature Tba performed.

  The determination as to whether or not the amount of water vapor in the air in the battery pack 20 is large is not limited to a method performed based on the in-pack air temperature Tbp and the in-pack humidity Hbp. For example, the dew condensation prevention control execution determination unit 102 is provided with a pressure sensor for detecting the pressure in the battery pack 20, and the period during which the pressure in the battery pack 20 is the same as the pressure outside the battery pack 20 is provided. It may be determined whether or not it continues for a predetermined period. When the internal pressure of the battery pack 20 and the external pressure are the same pressure, for example, when more than half a year has passed, the sealing of the case 21 is not maintained, and moisture is contained in the battery pack 20. It can be estimated that it has entered.

<2-3. Dew condensation temperature calculation unit>
The dew condensation temperature calculation unit 116 calculates the current dew condensation temperature Tde in the battery pack 20 based on the pack air temperature Tbp and the pack humidity Hbp. For example, the dew condensation temperature calculating unit 116 calculates the water vapor amount (g / m ³ ) in the battery pack 20 based on the saturated water vapor amount (g / m ³ ) of the current in-pack air temperature Tbp and the current in-pack humidity Hbp. ³ ) is estimated, and the air temperature at which the water vapor amount and the saturated water vapor amount coincide can be obtained as the dew condensation temperature Tde. However, the method for calculating the condensation occurrence temperature Tde is not limited to such an example.

  Similarly to the dew condensation prevention control execution determination unit 102, when a plurality of humidity sensors 28 are provided, the in-pack humidity Hbp used for the calculation may be the highest value of the detected in-pack humidity Hbp, or Alternatively, the average value of the detected in-pack humidity Hbp may be used. Further, when a plurality of second temperature sensors 26 are provided, the pack air temperature Tbp used for calculation may be the highest value or the lowest value of the detected pack air temperatures Tbp, or may be detected. It is good also as an average value of battery temperature Tba performed.

<2-4. Calorific value calculation section>
The calorific value calculation unit 118 estimates the self-heating value Vh of the secondary battery 22 based on at least one of a change in the running load of the vehicle, the required power to the secondary battery 22 and the battery temperature Tba. The self-heating value Vh estimated here is the total self-heating value Vh of all the secondary batteries 22 in the battery pack 20. For example, the heat generation amount calculation unit 118 predicts the amount of power required by the vehicle from the secondary battery 22 based on the change amount ΔAcc of the accelerator operation amount of the vehicle and the vehicle speed V, and calculates the self-heating value according to the amount of power. Can be estimated. Even during regenerative control of the secondary battery 22, the heat generation amount calculation unit 118 estimates the self-heat generation amount Vh by predicting the charge amount based on the change in the vehicle speed V when the accelerator operation amount Acc is zero. Can do. During automatic driving in which the driver does not perform the accelerator operation, the self-heating amount Vh of the secondary battery 22 may be estimated based on the amount of change in required driving force calculated by the control device.

  Further, the calorific value calculation unit 118 uses the electric power of the secondary battery 22 to control the various electric devices, and the self-heating of the secondary battery 22 based on the electric energy required for the air conditioning control device 100 from the control device. The amount Vh can also be estimated. Examples of such a control device include an inverter control device that executes control of an inverter of an electric motor or a motor as a generator, and an air conditioning management device that executes air conditioning control of a passenger compartment. However, the control device is limited to such a device. Not. The relationship between the required power amount or the charge amount and the self-heat generation amount can be obtained in advance as the characteristics of the secondary battery 22. In general, as shown in FIG. 3, the self-heating value Vh of the secondary battery 22 increases as the required power amount or the charged amount increases. In this case, the heat generation amount calculation unit 118 may calculate the self heat generation amount Vh with reference to map information indicating the relationship between the required power amount or the charge amount and the self heat generation amount.

  Furthermore, the heat generation amount calculation unit 118 may estimate the self-heating amount Vh of the secondary battery 22 based on the detected change in the battery temperature Tba. In this case, the heat generation amount calculation unit 118 can estimate the self-heat generation amount Vh of the secondary battery 22 in consideration of the change in the battery temperature Tba and the current control amount of the cooling device 30.

<2-5. Condensation prevention control unit>
The dew condensation prevention control unit 104 executes the dew condensation prevention control when it is determined that the dew condensation prevention control is necessary because the amount of water vapor in the battery pack 20 is large. When the condensation prevention control is executed, the condensation prevention control unit 104 controls the cooling device 30 so that the in-pack air temperature Tbp is maintained higher than the condensation occurrence temperature Tde.

  In a state where the vehicle has been stopped for a long time, the air temperature Tbp in the pack, the battery temperature Tba, and the temperature Tev on the surface of the evaporator 31 are values close to the outside air temperature, and no condensation occurs in the battery pack 20. On the other hand, after the vehicle is started, the battery temperature Tba and the air temperature Tbp in the pack rise due to self-heating of the secondary battery 22, or the battery temperature Tba, the air temperature Tpack in the pack Tbp, and the surface of the evaporator 31 are activated by the operation of the cooling device 30. If the temperature Tev decreases, condensation may occur in the battery pack 20. Therefore, the dew condensation prevention control unit 104 controls the cooling device 30 so that the in-pack air temperature Tbp is maintained higher than the dew condensation generation temperature Tde, and the in-pack air temperature Tbp and the battery temperature Tba are equal to or lower than the dew condensation generation temperature Tde. Do not become.

  In the present embodiment, when the condensation prevention control unit 104 executes the condensation prevention control, if the pack air temperature Tbp is lower than the condensation occurrence temperature Tde, the condensation prevention control unit 104 operates the heater 29 to set the pack air temperature Tbp. The dew condensation temperature Tde or higher. The target temperature of the in-pack air temperature Tbp when the heater 29 is operated can be set as appropriate. For example, the heater 29 may be operated until the temperature becomes 5 ° C. higher than the dew condensation temperature Tde. When the pack air temperature Tbp becomes equal to or higher than the condensation occurrence temperature Tde, the condensation prevention control unit 104 stops the heater 29 and starts control to maintain the pack air temperature Tbp higher than the condensation occurrence temperature Tde.

  In the present embodiment, the dew condensation prevention control unit 104 controls the evaporator from the expansion valve 32 so that the cooling capacity capable of canceling the heat generation amount Vh is developed based on the information related to the heat generation amount Vh of the secondary battery 22. The refrigerant injection amount to 31 is set. Thus, after the vehicle is started, the in-pack air temperature Tbp is held so as not to change greatly, and the occurrence of condensation on the metal portion other than the surface of the evaporator 31 is suppressed.

  As shown in FIG. 4, the amount of cooling air in the battery pack 20 increases as the amount of refrigerant injected into the evaporator 31 increases. The dew condensation prevention control unit 104 adjusts the passage area on the upstream side of the nozzle hole of the expansion valve 32 or adjusts the pressure of the refrigerant supplied to the expansion valve 32 so that the refrigerant to the evaporator 31 is adjusted. Control the injection amount of The dew condensation prevention control unit 104 determines the control amount of the expansion valve 32 and the cooling unit 34 based on the set refrigerant injection amount, and supplies the control amount to the expansion valve control unit 110 and the cooling auxiliary device control unit 112. Instruct. The output of the blower fan 24 may be variable.

  As illustrated in FIG. 5, the calorific value calculation unit 118 can be omitted by obtaining the relationship between the accelerator operation amount change ΔAcc and the refrigerant injection amount. In this case, the relationship between the change amount ΔAcc of the accelerator operation amount and the injection amount of the refrigerant may vary depending on the specifications of the battery pack 20 such as the shape and constituent material of the battery pack 20 and the mounting capacity of the secondary battery 22.

  Further, the dew condensation prevention control unit 104 ends the dew condensation prevention control when the in-pack air temperature Tbp reaches a predetermined stop reference value Tbp_fin after starting the dew condensation prevention control. Stop reference value Tbp_fin is set to a value higher than battery temperature Tbp at the start of dew condensation prevention control. That is, the dew condensation prevention control unit 104 sets a stop reference value Tbp_fin obtained by adding a predetermined margin Xt to the detected battery temperature Tbp at the start of the dew condensation prevention control. The margin Xt can be set to 10 ° C., for example.

  The fact that the battery temperature Tba reaches the stop reference value Tbp_fin means that the secondary battery 22 is generating heat to the extent that it is difficult to lower the battery temperature Tba by the cooling device 30, and the battery temperature Tba is condensed. This means that there is little possibility that the temperature is lower than the generation temperature Tde. Therefore, in this case, the dew condensation prevention control unit 104 ends the dew condensation prevention control. Thereafter, normal cooling control by the cooling control unit 114 is executed. Instead of the stop reference value Tbp_fin obtained by adding the margin Xt to the in-pack air temperature Tbp at the start of the condensation prevention control, the target management temperature Tba_tgt of the secondary battery 22 may be used as the stop reference value Tbp_fin.

<< 3. Battery pack air conditioning control method >>
The configuration of the air conditioning device 10 and the air conditioning control device 100 of the battery pack 20 has been described above. Next, an example of the air conditioning control method for the battery pack 20 executed by the air conditioning control device 100 will be described.

<3-1. Flow chart>
FIG. 6 is a flowchart illustrating an example of an air conditioning control method according to the present embodiment. First, in step S10, the air conditioning control device 100 reads the pack air temperature Tbp and the pack humidity Hbp. Next, in step S20, the air conditioning control device 100 calculates the condensation occurrence temperature Tde. For example, the air-conditioning control apparatus 100 reads the pack air temperature Tbp and the pack humidity Hbp, estimates the water vapor amount (g / m ³ ) in the battery pack 20, and the saturated water vapor amount (g / M ³ ) is calculated as the dew condensation temperature Tde.

  Next, in step S30, the air conditioning control device 100 determines whether or not the in-pack air temperature Tbp is lower than the condensation occurrence temperature Tde. In step S30, the in-pack air temperature Tbp may be compared with a value higher than the dew condensation temperature Tde by a predetermined temperature. When the air temperature Tbp in the pack is lower than the dew condensation temperature Tde (S30: No), the air conditioning control device 100 proceeds to step S70 and activates the heater 29 to execute the temperature increase control. For example, the air conditioning control device 100 operates the heater 29 until the in-pack air temperature Tbp becomes higher than the dew condensation generation temperature Tde by a predetermined temperature or more. When the temperature increase control in step S70 is completed, the process returns to step S10 and the processing of each step is repeated.

  On the other hand, if the air temperature Tbp in the pack is equal to or higher than the dew condensation occurrence temperature Tde in step S30 (S30: No), the air conditioning control device 100 proceeds to step S40 and determines whether or not the dew condensation prevention control execution condition is satisfied. To do. In the present embodiment, in step S40, the air conditioning control device 100 determines whether or not the in-pack humidity Hbp is equal to or higher than a predetermined start reference value Hbp_str and the in-pack air temperature Tbp is equal to or lower than a predetermined upper limit value Tbp_str_max. judge.

  If the dew condensation prevention control execution condition is not satisfied (S40: No), the air conditioning control device 100 proceeds to step S60 and starts normal cooling control. FIG. 7 is a flowchart illustrating an example of normal cooling control. In the normal cooling control, first, in step S61, the air conditioning control device 100 reads the battery temperature Tba. Next, in step S <b> 62, the air conditioning control device 100 determines whether or not the secondary battery 22 needs to be cooled. Specifically, the air conditioning controller 100 determines whether or not the battery temperature Tba exceeds the target management temperature Tba_tgt.

  When the battery temperature Tba is equal to or lower than the target management temperature Tba_tgt (S62: No), the secondary battery 22 does not need to be cooled, so the air conditioning control device 100 ends this routine and returns to step S10 in FIG. On the other hand, when the battery temperature Tba exceeds the target management temperature Tba_tgt (S62: Yes), the air conditioning control device 100 proceeds to step S63 and reads the temperature Tev on the surface of the evaporator 31.

  Next, in step S64, the air conditioning control device 100 determines whether or not the output of the cooling device 30 needs to be changed. Specifically, the air conditioning control device 100 determines whether or not the temperature Tev on the surface of the evaporator 31 exceeds the target temperature on the surface of the evaporator 31. The target temperature is set as a value of the temperature Tev on the surface of the evaporator 31 that can maintain the battery temperature Tba at the target management temperature Tba_tgt.

  If the temperature Tev on the surface of the evaporator 31 is equal to or lower than the target temperature (S64: No), there is no need to change the output of the cooling device 30, so the air conditioning control device 100 ends this routine and performs step S10 in FIG. Return to. On the other hand, when the temperature Tev on the surface of the evaporator 31 exceeds the target temperature (S64: Yes), the air conditioning control device 100 proceeds to step S65, and the temperature Tev on the surface of the evaporator 31 read in the previous cycle and the surface of the evaporator 31 read this time. The refrigerant injection amount to the evaporator 31 is calculated based on the temperature Tev. For example, the air-conditioning control apparatus 100 may perform feedback control of the refrigerant injection amount to the evaporator 31 so that the amount of decrease in the temperature Tev on the surface of the evaporator 31 from the previous cycle to the current cycle becomes a predetermined amount. Good.

  Next, in step S66, the air conditioning control device 100 calculates a required output of the cooling device 30. For example, the air-conditioning control apparatus 100 detects the pressure of the refrigerant supplied to the expansion valve 32 and calculates the opening time of the expansion valve 32 based on the refrigerant pressure and the refrigerant injection amount. . When duty control for changing the valve opening time of the expansion valve 32 during the unit time to control the refrigerant injection amount is performed, this corresponds to the ratio of the valve opening time of the expansion valve 32 during the unit time. Calculate the duty ratio.

  Next, in step S67, the air conditioning controller 100 outputs a control command to the expansion valve drive circuit based on the valve opening time of the expansion valve 32, and opens the expansion valve 32. Thereby, a refrigerant | coolant is injected with respect to the evaporator 31, the evaporator 31 is cooled, and the secondary battery 22 is cooled. Thereafter, the air-conditioning control apparatus 100 returns to step S10 in FIG. 6 again and repeats the procedure described so far.

  Returning to FIG. 6, when the dew condensation prevention control execution condition is satisfied in step S <b> 40 (S <b> 40: Yes), the air conditioning control device 100 proceeds to step S <b> 50 and executes the dew condensation prevention control. FIG. 8 is a flowchart showing the dew condensation prevention control. In the condensation prevention control, first, in step S51, the air conditioning control device 100 sets a stop reference value Tbp_fin for the in-pack air temperature Tbp for ending the condensation prevention control. For example, a value obtained by adding a predetermined margin Xt to the in-pack air temperature Tbp at the start of the dew condensation prevention control may be set as the stop reference value Tbp_fin, or the target management temperature Tb_tgt of the secondary battery 22 is set as the stop reference value Tbp_fin. May be.

  Next, in step S <b> 52, the air conditioning control device 100 calculates the amount of heat generated by the secondary battery 22. For example, the air conditioning control device 100 predicts the amount of power required by the vehicle from the secondary battery 22 based on the change amount ΔAcc of the accelerator operation amount of the vehicle and the vehicle speed V, and estimates the self-heating amount according to the amount of power. May be. Even during regenerative control of the secondary battery 22, the air conditioning control device 100 can estimate the self-heating value Vh by predicting the charge amount based on the change in the vehicle speed V when the accelerator operation amount Acc is zero. it can. During automatic driving in which the driver does not perform the accelerator operation, the self-heating amount Vh of the secondary battery 22 may be estimated based on the amount of change in required driving force calculated by the control device.

  In addition, the air conditioning control device 100 uses the power of the secondary battery 22 to control the various electric devices, and the self-heating amount of the secondary battery 22 is based on the amount of power required for the air conditioning control device 100 from the control device. Vh may be estimated. The relationship between the required power amount or the charge amount and the self-heat generation amount can be obtained in advance as the characteristics of the secondary battery 22. Further, the air conditioning control device 100 may estimate the self-heating amount Vh of the secondary battery 22 based on the detected change in the battery temperature Tba. The air conditioning control device 100 calculates the heat generation amount of the secondary battery 22 by at least one of the heat generation amount calculation methods exemplified here.

  Next, in step S <b> 53, the air conditioning control device 100 calculates the refrigerant injection amount to the evaporator 31. For example, the air-conditioning control apparatus 100 sets the refrigerant injection amount to the evaporator 31 so that the cooling capacity that can cancel the calorific value Vh of the secondary battery 22 calculated in step S52 is developed. Next, in step S54, the air conditioning control device 100 calculates a required output of the cooling device 30. For example, the air-conditioning control apparatus 100 detects the pressure of the refrigerant supplied to the expansion valve 32 and calculates the opening time of the expansion valve 32 based on the refrigerant pressure and the refrigerant injection amount. . When duty control for changing the valve opening time of the expansion valve 32 during the unit time to control the refrigerant injection amount is performed, this corresponds to the ratio of the valve opening time of the expansion valve 32 during the unit time. Calculate the duty ratio.

  Next, in step S55, the air conditioning control device 100 outputs a control command to the expansion valve drive circuit based on the valve opening time of the expansion valve 32, and opens the expansion valve 32. Thereby, a refrigerant | coolant is injected with respect to the evaporator 31, the evaporator 31 is cooled, and the secondary battery 22 is cooled. At this time, the pack air temperature Tbp is controlled to be held at the pack air temperature Tbp at the start of the dew condensation prevention control. Therefore, the in-pack air temperature Tbp is maintained higher than the dew condensation temperature Tde, and the battery temperature Tba does not fall below the dew condensation temperature Tde. Thereby, generation | occurrence | production of the dew condensation other than the surface of the evaporator 31 is suppressed.

  Next, in step S56, the air conditioning control device 100 determines whether or not the dew condensation prevention control stop condition is satisfied. For example, the air-conditioning control apparatus 100 determines whether the in-pack air temperature Tbp is equal to or higher than the stop reference value Tbp_fin. If the in-pack air temperature Tbp is less than the stop reference value Tbp_fin (S56: No), the air-conditioning control apparatus 100 returns to step S52 as it is and continues the dew condensation prevention control.

  On the other hand, when the in-pack air temperature Tbp is equal to or higher than the stop reference value Tbp_fin (S56: Yes), the air conditioning control device 100 ends the condensation prevention control. Even after the cooling device 30 is fully operated after the time when the in-pack air temperature Tbp becomes equal to or higher than the stop reference value Tbp_fin, the in-pack air temperature Tbp does not fall below the dew condensation occurrence temperature. Is possible. Thereafter, the air conditioning control device 100 returns to step S10 in FIG. 6 again and repeats the procedure described so far.

  As described above, in the air conditioning control method according to the present embodiment, when the amount of water vapor in the battery pack 20 is large, the cooling device 30 is configured so that the air temperature Tbp in the pack is maintained higher than the dew condensation temperature Tde. Be controlled. Therefore, it is prevented that the in-pack air temperature Tbp and the battery temperature Tba are equal to or lower than the dew condensation generation temperature Tde, and the occurrence of dew condensation in the metal portion other than the evaporator 31 is suppressed.

<3-2. Time chart>
Next, referring to the time chart, the change in the temperature inside the battery pack 20 when the air-conditioning control is executed by the air-conditioning control device 100 of the battery pack 20 according to this embodiment and the amount of refrigerant injected by the expansion valve 32 will be described. A brief description will be given. For comparison, the temperature change in the battery pack 20 when only the normal cooling control is executed without executing the dew condensation prevention control, and the refrigerant injection amount by the expansion valve 32 will be described, and then the present embodiment will be described. The air conditioning control will be described. In the following description, the case where the in-pack humidity Hbp is high due to, for example, intrusion of moist outside air into the battery pack 20 will be described.

  FIG. 9 is a time chart showing the transition of the in-pack air temperature Tbp, the battery temperature Tba, and the temperature Tev on the surface of the evaporator 31 when only the normal cooling control is executed. 9 shows the amount of refrigerant injected by the expansion valve 32. In this example, as the expansion valve 32, a valve that can be switched only when the refrigerant injection amount is 0 or 100 (%) is used.

  When only the normal cooling control is executed, when the battery temperature Tba exceeds the target management temperature Tba_tgt, the cooling device 30 is activated, and the refrigerant is injected by the expansion valve 32. However, when the temperature of the surface of the evaporator 31 is excessively lowered (in the example of FIG. 9, when it is below minus 5 ° C.), the refrigerant injection by the expansion valve 32 is stopped. According to this example, although the battery temperature Tba does not become the dew condensation generation temperature Tde or less, the in-pack air temperature Tbp becomes the dew condensation generation temperature Tde or less, and dew condensation occurs in the metal part other than the evaporator 31 (broken line). Region C) surrounded by As a result, water droplets adhere to the metal terminal of the secondary battery 22 due to vehicle vibration or the like, which may cause corrosion, leakage, or short circuit of the metal terminal.

  FIG. 10 is a time chart showing changes in the air temperature Tbp in the pack, the battery temperature Tba, and the temperature Tev on the surface of the evaporator 31 when the air conditioning control method according to the present embodiment is executed. Further, the refrigerant injection amount by the expansion valve 32 is shown on the lower side of FIG. In this example, an electric expansion valve that can adjust the injection amount of the refrigerant by 0 to 100 (%) is used as the expansion valve 32.

  In the air conditioning control method according to the present embodiment, when it is determined that the amount of water vapor in the battery pack 20 is large, the cooling device 30 performs dew condensation prevention control. In the dew condensation prevention control, the refrigerant injection amount by the expansion valve 32 is adjusted so that the cooling capacity capable of canceling the heat generation amount of the secondary battery 22 is exhibited. Therefore, the in-pack air temperature Tbp is kept higher than the condensation occurrence temperature Tde.

  During this time, as the amount of heat generated by the secondary battery 22 increases, the refrigerant injection amount of the expansion valve 32 also increases. Therefore, the temperature Tev on the surface of the evaporator 31 is lower than the dew condensation generation temperature Tde, and dew condensation occurs on the surface of the evaporator 31. On the other hand, as the amount of heat generated by the secondary battery 22 increases, the battery temperature Tba increases. Further, the pack air temperature Tbp changes at a substantially constant value as long as the cooling capacity of the cooling device 30 can exert an effect. Therefore, the occurrence of condensation on the surface other than the surface of the evaporator 31 is suppressed.

  As described above, according to the air conditioning control device 100 for the battery pack 20 according to the present embodiment, the dew condensation prevention control is executed when the amount of water vapor in the battery pack 20 is large. In the condensation prevention control, the output of the cooling device 30 is controlled so that the in-pack air temperature Tbp is maintained higher than the condensation occurrence temperature Tde. Accordingly, in the battery pack 20, the occurrence of dew condensation at a position other than the surface of the evaporator 31 is suppressed, and problems such as corrosion, electric leakage, and short circuit of the metal terminal of the secondary battery 22 are suppressed.

  In addition, according to the air conditioning control device 100 of the battery pack 20 according to the present embodiment, the output of the cooling device 30 so that no malfunction occurs in the battery pack 20 even when the humidity in the battery pack 20 increases. Is controlled. Therefore, according to the air conditioning control device 100 for the battery pack 20 according to the present embodiment, the replacement time of the battery pack 20 can be delayed, and the replacement cost of the battery pack 20 can be reduced. Moreover, according to the air-conditioning control apparatus 100 of the battery pack 20 according to the present embodiment, the corrosion prevention process for the battery pack 20 can be simplified, so that the manufacturing cost can be suppressed.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications or application examples within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Air conditioner 18 Duct 20 Battery pack 21 Case 22 Secondary battery 24 Blower fan 25 1st temperature sensor 26 2nd temperature sensor 27 3rd temperature sensor 28 Humidity sensor 29 Heater 30 Cooling device 31 Evaporator 32 Expansion valve Reference Signs List 33 Refrigerant circulation passage 34 Cooling unit 100 Air conditioning control device 102 Condensation prevention control execution determination unit 104 Condensation prevention control unit 108 Blower fan control unit 110 Expansion valve control unit 112 Cooling auxiliary device control unit 114 Cooling control unit 116 Calculation of condensation generation temperature 118 Heat generation amount calculation unit Acc Accelerator operation amount Hbp Humidity in pack Tba Battery temperature Tbp Air temperature in pack Tde Condensation occurrence temperature Tev Temperature of evaporator surface V Vehicle speed Vh Self-heating amount of secondary battery Xt Margin

Claims (6)

Air conditioning control of a battery pack for performing air conditioning control in a battery pack that is mounted on a vehicle and that supplies a secondary battery that supplies electric power to an electric motor as a drive source and a cooling device for cooling the secondary battery In the device
A dew condensation temperature calculating unit for calculating a dew condensation temperature based on the temperature and humidity of the air in the battery pack;
A dew condensation prevention control execution determination unit for determining whether the amount of water vapor in the air in the battery pack is large;
When it is determined that the amount of water vapor is large, a dew condensation prevention control unit that controls the cooling device so that the temperature of the air in the battery pack is maintained higher than the dew condensation occurrence temperature;
An air conditioning control device for a battery pack. The cooling device includes an evaporator and an electric expansion valve that adjusts a refrigerant injection amount to the evaporator,
2. The air conditioning control of the battery pack according to claim 1, wherein the dew condensation prevention control unit sets an opening degree of the electric expansion valve based on information related to a heat generation amount of the secondary battery and the dew generation temperature. apparatus.   3. The air conditioning control device for a battery pack according to claim 1, wherein the dew condensation prevention control unit controls the cooling device with an output capable of canceling a calorific value of the secondary battery.   When the temperature of the air in the battery pack becomes equal to or higher than a stop reference value that is higher than the temperature of the secondary battery at the start of the condensation prevention control, the condensation prevention control unit The air conditioning control device for a battery pack according to any one of claims 1 to 3, wherein the control for maintaining the temperature of the air higher than the dew condensation temperature is terminated.   The apparatus includes a calorific value calculation unit that calculates a calorific value of the secondary battery based on at least one of a running load of the vehicle, a required power to the secondary battery, and a temperature change of the secondary battery. The air conditioning control device for a battery pack according to any one of 1 to 4. The battery pack according to any one of claims 1 to 5, wherein the dew condensation prevention control execution determination unit determines whether or not the amount of water vapor is large based on a temperature and humidity of air in the battery pack. Air conditioning control device.

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