JP5659990B2 - Battery temperature control device - Google Patents

Description

  The present invention relates to a battery temperature adjusting device that adjusts the temperature of a secondary battery.

  In general, the discharge characteristics of a battery vary with the temperature of the battery. For example, when the temperature of the battery is low, the capacity of the battery that can be discharged is reduced, and sufficient output characteristics cannot be obtained. Therefore, in the case of a vehicle that travels by rotating the motor with battery power, such as an electric vehicle such as an electric vehicle or a hybrid vehicle, the start performance or the like when traveling in a low temperature environment such as traveling in winter or traveling in a cold region, etc. Running performance may deteriorate and sufficient output may not be obtained.

  On the other hand, it is known that when the temperature is high, the self-discharge of the battery increases and the remaining capacity of the battery tends to decrease. Therefore, when regenerative power generation is performed at the time of deceleration with the electric vehicle as described above, if the battery temperature rises excessively due to the environmental temperature or the heat generated by the battery itself, sufficient regenerative energy may not be obtained. Further, use at a high temperature tends to cause deterioration of the battery, leading to a reduction in battery life.

  Under these circumstances, a temperature range (that is, an upper limit value and a lower limit value) suitable for use of the battery is usually determined. For example, since the capacity of the battery decreases and the battery output decreases as the temperature decreases, the lower limit value of the operating temperature range is set to a temperature at which the required minimum battery output can be obtained. For electric vehicles equipped with a battery for traveling, various control methods for maintaining the battery temperature within a predetermined operating temperature range by using an in-vehicle cooling / heating device or the like have been proposed.

  For example, when the battery temperature is lower than the above lower limit value, the heating control is performed so that the battery temperature becomes the lower limit value. Regarding a technique for heating a battery, for example, Patent Document 1 describes a heat retention system for a secondary battery provided with an electric heater that heats the battery using regenerative energy generated during deceleration of an electric vehicle. . The electric heater is provided on the bottom surface of each secondary battery, and heats the secondary battery with regenerative power when the temperature of the secondary battery falls below a predetermined lower limit temperature (that is, lower limit value). Thus, the battery can be kept warm with a simple configuration. Moreover, the fall of the battery output resulting from the low temperature of a battery is suppressed.

JP 2008-103108 A

  By the way, as the battery progresses in deterioration (that is, when the degree of deterioration decreases), the battery output that can be taken out decreases. Therefore, even if a battery with a reduced degree of deterioration is used within the above-mentioned operating temperature range, the desired battery output May not be obtained. For example, in an electric vehicle equipped with a battery for traveling, it is necessary to obtain a battery output required to ensure at least startability, acceleration, and the like. However, a battery having a deteriorated degree may not be able to obtain this minimum battery output even if the battery temperature is raised to the lower limit of the operating temperature range. Such a problem may occur not only in a vehicle-mounted battery.

This case has been devised in view of such a problem, and a battery temperature control device capable of adjusting the temperature of the battery to ensure the minimum required output regardless of the deterioration of the battery. The purpose is to provide.
The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

  (1) A battery temperature adjusting device disclosed herein is a battery temperature adjusting device that adjusts the temperature of a secondary battery in which a use temperature range is set, and a heating unit that heats the secondary battery; A temperature sensor for detecting the temperature of the secondary battery, a deterioration degree estimating means for estimating the progress of deterioration of the secondary battery, and the deterioration of the secondary battery estimated by the deterioration degree estimating means is progressing. Setting means for setting the lower limit value of the operating temperature range higher, and when the temperature detected by the temperature sensor is less than the lower limit value set by the setting means, the heating battery is connected to the secondary battery. And a temperature control means for performing a heating control for heating.

The operating temperature range is a temperature range of the usage environment of the secondary battery set in advance based on, for example, chemical characteristics and durability of the secondary battery. In a secondary battery mounted on an electric vehicle such as a general electric vehicle or a hybrid vehicle, the use temperature range is set to approximately 10 to 30 ° C.
Further, the deterioration degree estimating means may be configured to estimate the deterioration degree. Here, the degree of deterioration is one of indexes indicating the degree of deterioration numerically, and is expressed, for example, as a percentage of the full charge capacity at that time with respect to the full charge capacity at the time of a new article. Therefore, in this case, the setting means sets the lower limit value of the operating temperature range higher as the secondary battery deteriorates.

(2) A plurality of the secondary batteries are provided, the temperature sensors are respectively provided in the plurality of secondary batteries, and the temperature control means is the lowest temperature among the plurality of temperatures detected by the temperature sensors. It is preferable to implement the heating control when is less than the lower limit.
The minimum temperature means the temperature of the lowest temperature among the plurality of secondary batteries.

(3) The battery temperature control device for the secondary battery in which the operating charging rate range is set, wherein the setting means discharges the new secondary battery to the lowest charging rate in the operating charging rate range. Preferably, the temperature at which a predetermined minimum capacity remains in the secondary battery is set as the lower limit value of the operating temperature range.
The operation charge rate range means the durability of the secondary battery, the output required by the electric device equipped with the secondary battery, the charging inside the battery determined by the operational request of the secondary battery, etc. This is the range of variation of the quantity. For secondary batteries mounted on electric vehicles such as general electric vehicles and hybrid vehicles, the upper limit of the operating charging rate range is set to 100%, the lower limit is set to around 40%, and the charging rate is less than the lower limit value. The secondary battery is operated so as not to be driven into the battery. The charge rate is one of indexes for easily grasping the electric power charged in the secondary battery, and is expressed, for example, as a percentage of the remaining capacity with respect to the capacity when fully charged.

  According to the battery temperature control apparatus of the present invention, the lower limit value of the operating temperature range of the battery is set higher as the deterioration of the secondary battery progresses, and heating is performed when the temperature of the secondary battery is less than this lower limit value. Since the secondary battery is heated by the means, the temperature of the secondary battery is adjusted in consideration of the decrease in the battery output accompanying the progress of the deterioration of the secondary battery to ensure the minimum required battery output. be able to.

It is a lineblock diagram of vehicles provided with a battery temperature control device concerning one embodiment. It is a graph which shows the relationship between a battery temperature and a battery output, (a) is a constant degradation degree of 100%, (b) is a constant degradation degree of 70%, (c) is a constant charge rate of 40%. State. It is a flowchart which shows the control content by the battery temperature control apparatus which concerns on one Embodiment.

Hereinafter, embodiments will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment.
[1. Device configuration]
The configuration of the battery temperature control device according to one embodiment will be described with reference to FIG. This temperature control device is suitable for use in an electric vehicle such as an electric vehicle or a hybrid vehicle. Here, a description will be given of an example applied to a hybrid vehicle.

  FIG. 1 is a configuration diagram of a vehicle provided with the temperature control device. As shown in FIG. 1, a vehicle 1 has an output shaft (rotary shaft) 2 a of an engine (ENG) 2 connected to a rotary shaft 4 a of a motor generator (hereinafter also referred to as “motor”) 4 via a clutch 3. 4 is configured as a parallel hybrid vehicle in which an input shaft 5a of a transmission (T / M) 5 is directly connected to a rotating shaft 4a. The output shaft 5b of the transmission 5 is connected to the left and right drive wheels 7 via a propeller shaft 6, a differential (not shown) and a drive shaft. Therefore, when the clutch 3 is connected, both the output shaft 2a of the engine 2 and the rotating shaft 4a of the electric motor 4 are mechanically connected to the drive wheels 7, and when the clutch 3 is disconnected, the electric motor 4 rotates. Only the shaft 4 a is mechanically connected to the drive wheel 7.

  The electric motor 4 operates as an electric motor (motor) when the DC power stored in the battery 10 is converted into AC power by the inverter 8 and supplied, and the driving force is converted to an appropriate speed by the transmission 5. It is transmitted to the drive wheel 7 later. Further, when the vehicle is decelerated, the electric motor 4 operates as a generator, and the kinetic energy generated by the rotation of the drive wheels 7 is transmitted to the electric motor 4 through the transmission 5 and converted into AC power, thereby generating a regenerative braking force. . The AC power is converted into DC power by the inverter 8 and then charged to the battery 10, and the kinetic energy due to the rotation of the drive wheels 7 is recovered as electric energy.

  On the other hand, the driving force of the engine 2 is transmitted to the transmission 5 via the rotating shaft 4a of the electric motor 4 when the clutch 3 is connected, and is transmitted to the drive wheels 7 after being shifted to an appropriate speed. . Therefore, when the electric motor 4 operates as a motor when the driving force of the engine 2 is transmitted to the driving wheels 7, the driving force of the engine 2 and the driving force of the electric motor 4 are transmitted to the driving wheels 7, respectively. . That is, a part of the drive torque to be transmitted to the drive wheels 7 for driving the vehicle 1 is supplied from the engine 2 and the rest is supplied from the electric motor 4.

  When the amount of power stored in the battery 10, that is, the charging rate of the battery 10 (State of Charge, hereinafter also referred to as SOC) decreases and the battery 10 needs to be charged, the motor 4 operates as a generator. The electric motor 4 is driven using a part of the driving force of the engine 2. As a result, power generation is performed, and the generated AC power is converted into DC power by the inverter 8 and then the battery 10 is charged. A heater 11 for heating the battery 10 is provided in the vicinity of the battery 10.

  Here, the battery 10 is an assembled battery in which a plurality of (three in FIG. 1) battery modules (secondary batteries) 21 are accommodated in a battery case 20. Each battery module 21 is, for example, an assembled battery in which a plurality of battery cells are accommodated in a case. The number of battery modules 21 is not limited to this. Moreover, the battery case 20 is being fixed to the arbitrary positions in the vehicle interior (for example, the inside of the trunk room of the vehicle 1, the inside of an instrument panel, etc.).

  The plurality of battery modules 21 are accommodated in the battery case 20 with a gap between them, and when cold air or hot air flows through the gap, the temperature is adjusted by cooling or heating. Each battery module 21 is provided with a temperature sensor 22, and the temperature of each battery module 21 is detected by each temperature sensor 22. The detected temperature information of each battery module 21 is transmitted to the vehicle ECU 15.

  The battery module 21 has a temperature range (use temperature range) suitable for use in advance. This use temperature range is a temperature range of the use environment of the battery module 21 set in advance based on, for example, chemical characteristics and durability of the battery module 21. In a secondary battery mounted on an electric vehicle such as a general electric vehicle or hybrid vehicle, the operating temperature range is set to approximately 10 to 30 ° C. That is, the upper limit value (upper limit temperature) and lower limit value (lower limit temperature) of the use temperature are set, and the use temperature range is set.

  In addition, the battery module 21 has a charge rate range (operation charge rate range) that can be used (operated) in advance. This operating charge rate range refers to, for example, the durability of the battery module 21, the output required by the electrical equipment equipped with the battery module 21, the amount of charge inside the battery determined by the operational requirements of the battery module 21, etc. It is a fluctuation range. In a secondary battery mounted on an electric vehicle such as a general electric vehicle or hybrid vehicle, the upper limit of the operating charging rate range is set to 100%, the lower limit is set to around 40%, and the charging rate is set to the lower limit value. The secondary battery is operated so as not to be driven below (so as not to decrease). This lower limit is appropriately set depending on the type of secondary battery. The charge rate is one of the indexes for easily grasping the electric power charged in the battery, for example, expressed as a percentage of the remaining capacity with respect to the capacity at the time of full charge (the amount of electricity remaining in the battery). When expressed by an equation, it is defined by the following equation (1).

  The battery module 21 is subjected to cooling control or heating control so that the temperature of the battery module 21 is within this operating temperature range by a temperature control unit 15d described later provided in the vehicle ECU 15. In other words, when the temperature of the battery module 21 is lower than the lower limit value, heating control is performed to raise the temperature of the battery module 21 to the lower limit value or more. Further, when the temperature of the battery module 21 is higher than the upper limit value, cooling control is performed, and the temperature of the battery module 21 is lowered to the upper limit value or less. Moreover, heating control or cooling control is also performed when the temperature of the battery module 21 falls below the lower limit value or exceeds the upper limit value from a state where the temperature is within an appropriate operating temperature range. That is, this lower limit value is a target value for performing the heating control, and is a threshold value for determining whether or not to perform the heating control. Similarly, this upper limit value is a target value for performing the cooling control. At the same time, it is a threshold value for determining whether or not to implement cooling control.

  The heater (heating means) 11 is a heater such as a PTC heater, for example, and the on / off of the switch is controlled by the temperature control unit 15d. The battery 10 has a flow path 11 a for taking hot air into the battery case 20. On this flow path 11a, a switching valve (not shown) for switching between taking in hot air into the battery case 20 or blocking the flow of hot air is provided, and the operation of this switching valve is controlled by the temperature controller 15d. Controlled by. In conjunction with the operation of the switching valve, the heater 11 is turned on when the battery 10 is heated. That is, when the heating control of the battery 10 is performed, the switching valve is controlled so that the heater 11 is turned on and hot air is taken into the battery case 20. Moreover, when heating control is complete | finished, the switch is controlled so that the switch of the heater 11 is turned off and the flow of hot air is interrupted.

The battery 10 also has a flow path (not shown) for taking cold air into the battery case 20. On this flow path, a switching valve is provided for switching between taking cold air into the battery case 20 or blocking the flow of cold air, and the operation of this switching valve is controlled by the temperature control unit 15d. That is, when the cooling control of the battery 10 is performed, the switching valve is controlled so that the cool air flows into the battery case 20, and when the cooling control is finished, the switching valve is controlled so as to shut off the cool air flow. To do.
Note that the above-described heating control and cooling control of the battery 10 are examples, and the heating control or cooling control of the battery 10 may be performed by a method other than the above.

In addition, the vehicle 1 is provided with an electronic control unit (hereinafter referred to as ECU) that controls these devices. That is, the vehicle 1 is provided with an engine ECU (ENG_ECU) 12 that controls the engine 2, an inverter ECU 13 that controls the inverter 8, and a vehicle ECU 15 that manages the battery 10 and controls the heater 11. The vehicle ECU 15 also performs integrated control of the vehicle 1 through the engine ECU 12 and the inverter ECU 13. The engine ECU 12, the inverter ECU 13, and the vehicle ECU 15 are computers each composed of a memory (ROM, RAM), a CPU, and the like.
In addition, about each function of engine ECU12 and inverter ECU13, since a well-known technique is applicable, it abbreviate | omits for details.

[2. Control configuration]
The vehicle ECU 15 includes a functional element as the battery management unit 15a, a functional element as the deterioration degree estimation unit 15b, a functional element as the setting unit 15c, and a functional element as the temperature control unit 15d.

The battery management unit (battery management unit, BMU) 15a detects the temperature and voltage of the battery 10, the current flowing between the inverter 8 and the battery 10, and calculates the charging rate of the battery 10 from these detection results. The state of the battery 10 is monitored so as not to be overcharged or overdischarged. Here, the battery management unit 15a collects the temperatures of all the battery modules 21 detected by the temperature sensor 22, and from these temperature information, the battery module 21 having the highest temperature among the temperatures of all the battery modules 21 is collected. The temperature (hereinafter referred to as the maximum temperature) T _MAX and the temperature (hereinafter referred to as the minimum temperature) T _{MIN of the} lowest temperature battery module 21 are selected and acquired. In other words, the highest temperature among the temperatures distributed in the battery case 20 is the highest temperature _TMAX , and the lowest temperature is the lowest temperature _TMIN . The information acquired by the battery management unit 15a is transmitted to the temperature control unit 15d.

  The deterioration degree estimation unit (deterioration degree estimation means) 15b estimates the degree of progress of deterioration of the battery module 21 (that is, the deterioration degree). Here, the degree of degradation (State of Health, hereinafter also referred to as SOH) is one of indexes indicating the degree of degradation, and is expressed by, for example, a percentage of the full charge capacity at that time with respect to the full charge capacity at the time of a new article. Is done. The degree of deterioration is also called the remaining life (soundness) of the battery, and is expressed by the following formula (2) when expressed by a formula. In other words, the degree of deterioration means that SOH = 100% is a new product (that is, the higher the degree of deterioration, the more the deterioration does not progress), and the lower the degree of deterioration, the more the deterioration proceeds. (That is, the remaining life of the battery is shortened).

  The deterioration degree estimation unit 15b estimates the deterioration degree of the battery module 21 by a known method. For example, as described in Japanese Patent Application Laid-Open Nos. 2000-131404 and 2010-78530, the degree of deterioration is estimated from the capacity when the battery is fully charged and the internal resistance of the battery. Note that the degradation degree estimation method is not particularly limited, and various methods can be applied. Further, the degree of deterioration of each battery module 21 may be estimated and the average value thereof may be used as the degree of deterioration of the battery 10. The degree of deterioration of any one of the battery modules 21 is estimated and this value is used as the degree of deterioration of the battery 10. It is good. Information on the deterioration level of the battery module 21 estimated by the deterioration level estimation unit 15b is transmitted to the setting unit 15c.

The setting unit (setting unit) 15c sets a lower limit value (hereinafter referred to as an initial lower limit value) of the operating temperature range of the battery module 21 in accordance with the degree of deterioration estimated by the deterioration degree estimating unit 15b. . Specifically, the setting unit 15c sets the lower limit value from the initial lower limit value to a higher value as the deterioration degree is lower (as the deterioration progresses). This lower limit value is a target value (that is, target temperature) when performing the heating control as described above, and is a temperature threshold value for determining whether or not to perform the heating control. Hereinafter, this initial lower limit value is also referred to as an initial target heating temperature T _TH .

Incidentally, it is generally known that a battery has the following three properties.
First, as shown in FIG. 2A, when the degree of deterioration is constant and the charging rate is also constant, the battery output is larger as the battery temperature is higher, and the battery output is smaller as the battery temperature is lower. .

Second, if the change gradient of the output with respect to the battery temperature is G, as shown in FIG. 2B, when the deterioration degree is constant, the gradient G is larger as the charging rate is higher and the gradient G is lower as the charging rate is lower. Is small (that is, the gradient G _b1 when the charging rate is 100%> the gradient G _b2 when the charging rate is 40%). That is, when the degree of deterioration is constant, if the battery temperature is the same, a battery with a higher charging rate can obtain a larger output, and a battery with a lower charging rate has a smaller output. An angle A in FIG. 2A and an angle B in FIG. 2B indicate the difference in change gradient of output with respect to battery temperature at a charging rate of 100% and a charging rate of 40%.

Third, similarly, assuming that the change gradient of the output with respect to the battery temperature is G, as shown in FIG. 2C, when the charging rate is constant, the gradient G is larger as the deterioration degree is higher, and the deterioration degree is lower. The gradient G is small (that is, the gradient G _c1 when the degree of deterioration is 100%> the gradient G _c2 when the degree of deterioration is 70%). That is, when the charging rate is constant, if the battery temperature is the same, a battery having a higher degree of deterioration can obtain a larger output, and a battery having a lower degree of deterioration (deteriorating progress) has a smaller output. Become. This is because the capacity when fully charged decreases as the secondary battery deteriorates. Therefore, even if the charging rate is the same, the remaining capacity of the battery decreases as the secondary battery deteriorates. An angle C in FIG. 2C indicates a difference in output change gradient with respect to the battery temperature between the deterioration degree 100% and the deterioration degree 70%.

  In addition, the charge rate of the battery is SOC = 100%, which is the upper limit (that is, full charge) of the operation charge rate range, and the lower limit of the operation charge rate range due to charging / discharging (when over discharge occurs, , And this is referred to as SOC = 40%, which is hereinafter referred to as a practical lower limit). Here, the practical lower limit is set to SOC = 40%, but the present invention is not limited to this, and the charge rate at the practical lower limit varies depending on the type of battery.

As described above, the output of the battery varies depending on the temperature, the charging rate, and the degree of deterioration. Note that the output P _MIN shown in these FIGS. 2A to 2C is the minimum value (necessary lower limit output) of the battery output required in the vehicle 1. The necessary lower limit output P _MIN is, for example, a battery output for ensuring startability, acceleration performance, and climbing ability at a minimum, or a battery for ensuring minimum shift torque loss with the motor 4 when the transmission 5 is AMT. It is output etc., and is set according to the type and performance of the vehicle.

The setting unit 15c causes the battery module 21 to have a predetermined minimum capacity when discharging a new battery module 21 (deterioration degree: 100%) to the lowest charging rate (practical lower limit, SOC = 40% in this case) within the operating charging rate range. Is set as the initial lower limit value (initial target heating temperature) T _TH of the operating temperature range of the battery module 21. Here, the predetermined minimum capacity is a capacity sufficient to obtain the necessary lower limit output _PMIN . In other words, setting unit 15c, the battery temperature T _a2 when the output shown in FIG. 2 (a) to the charging rate 40% in the graph a2 showing showing the state of the deterioration degree of 100% is required lower output P _MIN, the battery module 21 _Is set as the initial lower limit value _TTH .

The setting unit 15c is based on the required lower limit output P _MIN when the charging rate is 40%, as shown in FIG. 2A, when the charging rate is the practical lower limit (SOC = 40%) as described above. This is because the temperature T _{a2 at} which the required power is obtained is higher than the temperature T _{a1 at} which the necessary lower limit output P _MIN is obtained when the charging rate is 100%. That is, since the charging rate of the battery fluctuates between SOC = 100% and 40%, if the higher temperature (that is, SOC = 40%) is used as a reference (initial lower limit value T _TH ), the charging rate is affected. This is because the required lower limit output P _MIN can be secured by heating the battery module 21 to the initial lower limit value T _TH . In this way, if the charging rate is considered to be a practical lower limit, there is no need to consider output changes due to fluctuations in the charging rate, so the charging rate is also based on the practical lower limit for the following correction of the target heating temperature. To do.

On the other hand, as described above, the setting unit 15c sets the initial lower limit value _TTH to a higher value as the deterioration degree is lower. This is because when the temperature and the charging rate of the battery are constant, the battery output decreases as the deterioration degree decreases (the above third property). That is, as shown in FIG. 2B, when the degree of deterioration decreases from 100% to 70% (when deterioration progresses), even when the battery temperature is set to the initial lower limit value T _TH , Necessary lower limit output _PMIN cannot be obtained. In the case of FIG. 2B (when the deterioration degree is 70%), in order to ensure the necessary lower limit output P _MIN even when the charging rate becomes 40%, the battery temperature is set to a temperature T higher than the initial lower limit value T _TH. Must be _b2 . Therefore, the setting unit 15c sets the temperature T _b2 higher than the initial lower limit value T _{TH as} the target heating temperature T _TH ′ when the deterioration degree is 70%.

In other words, when the degree of deterioration decreases from 100%, the setting unit 15c sets the target heating temperature higher than the initial lower limit value T _TH by the amount of decrease in the degree of deterioration (for example, 30%). That is, the target temperature correction amount corresponding to the degree of deterioration is added to the initial lower limit value _TTH . That is, as shown in FIG. 2 (c), when the degree of deterioration is 100%, if the battery is heated up to the initial lower limit value _TTH and the temperature is raised, the required lower limit even if the charging rate is 40% of the practical lower limit. An output P _MIN can be obtained. When the degree of deterioration decreases, the target heating temperature is set higher than the initial lower limit value T _TH (the target heating temperature T _TH ′ is set according to the degree of deterioration), and this set target heating temperature is set. If the battery is heated up to T _TH ′ (hereinafter also referred to as a target heating temperature after setting), the required lower limit output P _MIN can be obtained even if the charging rate is 40%.

Table 1 below shows an example of a correction amount (target temperature correction amount) according to the degree of deterioration of the battery. In Table 1, the correction amount increases by 2 ° C. every time the degree of deterioration decreases by 10%. This correction amount is added to the initial lower limit value T _TH . For example, the post-setting target heating temperature T _TH ′ when the deterioration degree is 80% is a value obtained by adding 4 ° C. to the initial lower limit value T _TH. It becomes. Note that this Table 1 is merely an example, and the target temperature correction amount varies depending on the type and nature of the battery and is stored in advance in the vehicle ECU 15 according to the battery module 21 mounted on the vehicle 1.

The setting unit 15c obtains the target temperature correction amount from the deterioration degree estimated by the deterioration degree estimation unit 15b using the relationship between the deterioration degree and the correction amount stored in advance as shown in Table 1 above, and sets the initial lower limit. Add to the value T _TH and set the target heating temperature T _TH 'after setting. The target heating temperature T _TH ′ after this setting is transmitted to the temperature control unit 15d.

The setting of the lower limit value as described above by the setting unit 15c affects the operation method of the battery module 21 regardless of the heating control implementation state. For example, in a state where the temperature of the battery module 21 is lower than the set target heating temperature T _TH ′ (at the start of use of the battery, at the time of cold start), the control target temperature of the heating control is increased. In addition, in a state higher than the set target heating temperature T _TH ′ (when the battery is being used or running), the heating control is not performed, but the threshold temperature that is a criterion for determining whether or not to perform the heating control Is increased. Therefore, the temperature of the battery module 21 is maintained at a higher temperature. Further, even when the temperature of the battery module 21 decreases due to a decrease in the outside air temperature, the heating control is started at a higher temperature.

The temperature control unit (temperature control means) 15d performs cooling control or adjustment to adjust the temperature of the battery 10 to an appropriate temperature based on the maximum temperature _TMAX and the minimum temperature _TMIN transmitted from the battery management unit 15a. Heating control is performed.
First, referring to cooling control for the temperature control unit 15d is the upper limit of the maximum temperature T _MAX is the operating temperature range is higher than (the target cooling temperature) T _TC, it is determined that it is necessary to cool the battery 10 Then, cooling control of the battery 10 is performed. Here, the temperature control unit 15d performs cooling control by controlling the switching valve and taking in cool air into the battery case 20. The target cooling temperature _TTC is a threshold value for determining whether or not to cool the battery 10. This target cooling temperature _TTC is preset according to the battery module 21 used.

Next, the heating control will be described. The temperature control unit 15d acquires the target heating temperature T _TH ′ set in the setting unit 15c, and the minimum temperature T _{MIN and} the set target heating temperature T _TH ′. And compare. Then, when the minimum temperature T _MIN is lower than the set target heating temperature T _TH ′, it is determined that the battery 10 needs to be heated, and the heating control of the battery 10 is performed. Here, the temperature control unit 15d performs warming control by turning on the heater 11 and controlling the switching valve.
Further, the temperature control unit 15d determines that the battery module 21 has a maximum temperature T _MAX equal to or lower than the target cooling temperature T _TC and the minimum temperature T _MIN is equal to or higher than the set target heating temperature T _TH ′. 21 is determined to be within the range of the operating temperature, and neither cooling control nor heating control is performed.

[3. flowchart]
Next, an example of a temperature adjustment control procedure performed by the vehicle ECU 15 will be described with reference to FIG. This flowchart operates at a predetermined cycle. Each of the following steps is performed by each function (means) assigned to the hardware of the computer being operated by software (computer program).
When the driver turns on the ignition switch (IG_SW) of the vehicle 1, the temperature control device starts the following control flow.

As shown in FIG. 3, first, in step S10, it is determined whether or not the flag F = 0. Here, the flag F is a variable for checking whether or not the setting by the setting unit 15c described above is performed, and the flag F = 0 is set at the start of control. Therefore, at the start of control, the YES route is obtained in step S10, and the process proceeds to step S20. In step S20, the deterioration level of the battery module 21 is estimated by the deterioration level estimation unit 15b. Next, in step S30, setting of the target heating temperature is performed by the setting unit 15c, and the target heating temperature T _TH ′ after setting is acquired. In step S40, the flag F is set to F = 1, and the process proceeds to step S50.

In step S50, the temperature of each battery module 21 is detected from each temperature sensor 22, and the maximum temperature _TMAX and the minimum temperature _TMIN are acquired among these temperatures. In step S60, it is determined whether or not the minimum temperature T _MIN is lower than the set target heating temperature T _TH ′. If the minimum temperature T _MIN is not less than the set target heating temperature T _TH ′, the process proceeds from the NO route to step S70, where it is determined whether the maximum temperature T _MAX is higher than the target cooling temperature T _TC .

If it is determined in step S60 that the minimum temperature T _MIN is lower than the set target heating temperature T _TH ′, the process proceeds from the YES route to step S80, where heating control is performed. Further, when the maximum temperature T _MAX is determined to be higher than the target cooling temperature T _TC at step S70, the flow advances from YES route to step S90, cooling control is performed. On the other hand, if it is determined in step S70 that the maximum temperature _TMAX is equal to or lower than the target cooling temperature _TTC , the process proceeds from the NO route to step S100. If NO in step S60 and NO in step S70, the temperature of the battery module 21 is within an appropriate temperature range, so neither heating control nor cooling control is performed.

  In step S100, it is determined whether or not the ignition switch is off. If it is on, the process returns. In step S10, it is determined again whether or not the flag F is F = 0. At this time, since the flag F is set to F = 1, in the determination in step S10, the process proceeds from the NO route to step S50, and steps S50 to S100 are repeated to adjust the temperature of the battery module 21. That is, the estimation of the degree of deterioration in step S20 and the setting of the target heating temperature according to the degree of deterioration in step S30 are performed only when the ignition switch is turned on (that is, only once after the vehicle 1 is started). The On the other hand, if it is determined in step S100 that the ignition switch is OFF, the flag F is reset to F = 0 in step S110, and the control flow ends.

[4. effect]
Therefore, according to this battery temperature control apparatus, even if the deterioration degree of the battery module 21 is reduced (deterioration progresses) and the battery output that can be taken out is reduced, the initial lower limit value (initial value) of the operating temperature range of the battery module 21 Target heating temperature) T _TH is set high, and the target heating temperature T _TH ′ after setting is obtained. When the temperature of the battery module 21 is lower than the set target heating temperature T _TH ′, the heater 11 is controlled to raise the temperature of the battery module 21, so that the battery output accompanying the deterioration of the battery module 21 is lowered. In consideration of this decrease, the temperature of the battery module 21 can be adjusted to ensure the minimum required battery output _PMIN .

Here, the battery 10 is configured by housing a plurality of battery modules 21 in the battery case 20, and the target temperature T _TH after the minimum temperature T _MIN among the temperatures of the plurality of battery modules 21 is set. When the temperature is less than ′, the heater 11 is controlled to raise the temperature of the battery module 21, so that even if the battery module 10 is configured, the minimum output P _MIN required to suppress a decrease in output performance is suppressed. It can be surely secured.

Moreover, if the charging rate of the battery module 21 falls, the battery output which can be taken out will fall, even if it is the same battery temperature. On the other hand, the setting unit 15c determines the temperature at which a predetermined minimum capacity remains in the battery module 21 when the new battery module 21 is discharged to the minimum charging rate (practical lower limit) in the operating charging rate range. Since it is set as the lower limit value (initial lower limit value) T _TH of the range, it is not necessary to consider output changes due to fluctuations in the charging rate, and the target heating temperature T _TH ′ can be easily set according to the degree of deterioration. it can.

[5. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above temperature adjustment control, it is first determined whether or not heating control is necessary, and then it is determined whether or not cooling control is necessary (steps S60 and S70 in FIG. 3). ), It may be determined first whether or not cooling control is necessary.

Moreover, in the said embodiment, although temperature control of the battery 10 comprised by accommodating the several battery module 21 in the battery case 20 was demonstrated to the example, this battery temperature control apparatus is applicable to a single secondary battery. The target of temperature adjustment is not limited to the battery module 21 or the battery 10 as described above. Further, if the temperature of the single secondary battery is adjusted, only one temperature sensor is required, and it is not necessary to acquire the maximum temperature and the minimum temperature.
The means for heating the secondary battery is not limited to the heater, and any means can be used as long as the temperature of the secondary battery can be raised.

Further, although the case where the battery charge rate is the practical lower limit (SOC = 40%) is used as a reference, the case where the charge rate is the practical lower limit may not be used as a reference in consideration of a decrease in output due to the charge rate.
In the above embodiment, the minimum temperature of the battery module 21 is the target heating temperature T _TH after setting 'is lower than the target heating temperature T _TH after the setting' out the warming control such that However, for example, when the temperature of the battery module 21 gradually decreases from a state higher than the target heating temperature after setting and becomes lower than the target heating temperature after setting, the heating control is performed. carry out.

Further, the secondary battery may not be configured as a battery module, and may be a single battery cell.
Further, although the battery module 21 mounted on the parallel hybrid vehicle has been described as an example, the vehicle 1 is not limited to the hybrid vehicle, and can be applied to an electric vehicle such as an electric vehicle. Further, the battery 10 may not be mounted on the vehicle.

1 vehicle 10 battery 11 heater (heating means)
15 Vehicle ECU
15a Battery management unit (battery management unit, BMU)
15b Deterioration degree estimation unit (deterioration degree estimation means)
15c setting part (setting means)
15d Temperature control unit (temperature control means)
21 Battery module (secondary battery)
22 Temperature sensor

Claims (3)

A battery temperature adjusting device for adjusting the temperature of a secondary battery having a set operating temperature range,
Heating means for heating the secondary battery;
A temperature sensor for detecting a temperature of the secondary battery;
A deterioration degree estimating means for estimating a progress degree of deterioration of the secondary battery;
Setting means for setting the lower limit value of the operating temperature range higher as the deterioration of the secondary battery estimated by the deterioration degree estimating means progresses;
Temperature control means for performing heating control for heating the secondary battery to the heating means when the temperature detected by the temperature sensor is less than the lower limit value set by the setting means. A battery temperature control device. A plurality of the secondary batteries are provided,
The temperature sensors are respectively provided in the plurality of secondary batteries;
2. The battery temperature according to claim 1, wherein the temperature control unit performs the heating control when a minimum temperature among the plurality of temperatures detected by the temperature sensor is less than the lower limit value. Adjusting device. A battery temperature control device for the secondary battery in which an operating charging rate range is set,
The temperature at which the predetermined minimum capacity remains in the secondary battery when the setting unit discharges the new secondary battery to the minimum charging rate in the operating charging rate range is set as the lower limit value of the operating temperature range. The battery temperature control device according to claim 1, wherein the battery temperature control device is set.

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