Patent ID: 12214697

DESCRIPTION OF EMBODIMENTS

A battery temperature adjustment system according to an embodiment of the present disclosure will be described below with reference to the drawings.

[Vehicle]

As shown inFIGS.1and2, a battery temperature adjustment system1according to the present embodiment is mounted on a vehicle V. The vehicle V is, for example, an electric vehicle such as a plug-in hybrid vehicle or an electrical vehicle, and is configured such that a battery2can store electric power from an external power source10provided at a charging station, at home, or the like. The vehicle V is configured to be able to travel by driving a motor7as a drive source by the electric power stored in the battery2.

The vehicle V is connected to (plugged into) the external power source10by connecting, to a charging inlet8provided in the vehicle V, a charging plug11aof a charging cable11extending from the external power source10. It should be noted that the connection between the vehicle V and the external power source10is not limited thereto. For example, the vehicle V may be provided with an electric power receiving coil or the like capable of contactlessly receiving electric power transmitted from the external power source10.

The vehicle V is configured to be able to communicate with a user terminal20held by a user. The user terminal20is, for example, a smartphone or a tablet terminal that can be carried by the user, and may be a navigation device installed in the vehicle V. The user can set an upper limit of a state of charge (hereinafter also referred to as SOC) of the battery2by the user terminal20, and the set upper limit of the SOC is stored in a battery control unit5adescribed later. For example, when the user desires a high SOC state in order to increase a travelable distance of the vehicle V, the user can set the upper limit of the SOC to a high level in advance.

[Battery Temperature Adjustment System]

The battery temperature adjustment system1includes the battery2, a cooling device3that cools the battery2, a sensor unit4that detects a state of the battery2, and a control device5that controls the cooling device3.

The battery2is formed by stacking a plurality of battery cells (not shown), and is, for example, a lithium ion battery or a nickel metal hydride battery. The battery2is connected to the external power source10by connecting the charging plug11ato the charging inlet8, and is configured to be able to store the electric power from the external power source10. The electric power stored in the battery2is converted from a direct current into an alternating current by an inverter included in an electric power conversion device6, and is supplied to the motor7. In addition, when an alternating current generated by the motor7during braking of the vehicle V is input to the electric power conversion device6, the alternating current is converted to a direct current by the inverter and supplied to the battery2. That is, the battery2is configured to be able to store regenerated electric power.

The cooling device3cools the battery2by causing a refrigerant to flow through a refrigerant flow channel provided in the battery2. The cooling device3is, for example, a water-cooled type, circulates the refrigerant by a pump, and cools the refrigerant by a radiator. It should be noted that a heater is provided in the cooling device3, and the battery2can also be heated.

The electric power stored in the battery2is supplied to the cooling device3. In addition, when the vehicle V is connected to the external power source10, the electric power from the external power source10can be supplied to the cooling device3. Although details will be described later, when the vehicle V is connected to the external power source10, the electric power from the external power source10and the electric power from the battery2are selectively supplied to the cooling device3according to the present embodiment.

The sensor unit4includes a temperature sensor4athat acquires a temperature of the battery2(hereinafter also referred to as battery temperature), a voltage sensor4bthat measures a voltage of the battery2, and a current sensor4cthat measures a current flowing through the battery2.

The control device5includes the battery control unit5athat controls charging and discharging of the battery2and a cooling control unit5bthat controls the cooling device3. For example, the control device5is implemented by an electronic control unit (ECU) including a processor, a memory, an interface, and the like. It should be noted that the battery control unit5aand the cooling control unit5bmay be configured as separate control devices.

The battery temperature, the voltage of the battery2, the current of the battery2, and the like are input from the sensor unit4to the battery control unit5a. In addition, the battery control unit5acalculates the SOC of the battery2based on the input voltage and current. The battery control unit5acontrols charging and discharging of the battery2based on these input values and the SOC.

The battery control unit5astores in a memory or the like a deterioration sensitivity map (seeFIGS.3and4) in which a deterioration sensitivity of the battery2is preset according to the SOC and the battery temperature. Details of the deterioration sensitivity and the deterioration sensitivity map will be described later.

The cooling control unit5boperates the cooling device3such that the battery temperature is within a predetermined temperature range. In addition to operating the cooling device3while the vehicle V is traveling, the cooling control unit5boperates the cooling device3such that the battery temperature is maintained within the predetermined temperature range when the battery temperature exceeds the predetermined temperature range even while the vehicle V is parked. The time when the battery temperature exceeds the predetermined temperature range while the vehicle V is parked corresponds to, for example, a time when the vehicle V is parked in a high temperature environment for a certain period of time.

A cooling device in the related art is configured to be operated by electric power supplied from an external power source when a vehicle is connected to the external power source, and does not consume electric power of a battery during cooling. On the other hand, the cooling device3according to the present embodiment is configured such that even when the vehicle V is connected to the external power source10, either the electric power from the external power source10or the electric power from the battery2is selected based on the deterioration sensitivity, and the cooling device3can be operated by the selected electric power.

The deterioration sensitivity represents a degree of tendency toward deterioration of the battery2per unit time. The higher the deterioration sensitivity, the more likely the deterioration per unit time progresses, and the lower the deterioration sensitivity, the less likely the deterioration per unit time progresses. The deterioration sensitivity is set according to the state of charge of the battery2and the battery temperature. The deterioration sensitivity can be obtained from a deterioration sensitivity map in which preset deterioration sensitivities are mapped. In addition, the deterioration sensitivity may be sequentially calculated based on a preset formula or the like. In the following description, control for cooling the battery2will be described by taking, as an example, a case in which the deterioration sensitivity is obtained from the deterioration sensitivity map.

[Deterioration Sensitivity Map]

A deterioration sensitivity map of the batter2stored in the battery control unit5awill be described with reference toFIGS.3and4. It should be noted that deterioration sensitivity maps shown inFIGS.3and4are examples, and the deterioration sensitivity map also changes according to a battery to be used.

In the deterioration sensitivity map, a horizontal axis represents a battery temperature T and a vertical axis represents the SOC, and the deterioration sensitivity map shows a deterioration sensitivity preset according to the battery temperature and an SOC value. The battery temperature T is increased toward a right side of the drawings, and the SOC is increased toward an upper side of the drawings. The deterioration sensitivity takes a value between 0 and 1, and the lower the deterioration sensitivity, the less likely the deterioration of the battery2per unit time progresses, that is, the higher the deterioration prevention effect of the battery2.

FIGS.3and4each show a state where the battery2is currently in a high temperature and high SOC state (T0, SOC0) and a current deterioration sensitivity X0 is high (that is, the battery2is easily deteriorated). Here, the high temperature means that the temperature of the battery2is higher than a predetermined temperature range (for example, around 40° C.), and the high SOC means that the SOC of the battery2is higher than a predetermined SOC range (for example, around 80%).

When the vehicle V is connected to the external power source10, the battery control unit5aestimates an estimated value (T1, SOC1) of the battery temperature and the SOC after cooling when the cooling device3is operated by the electric power from the external power source10. In this case, since the electric power of the battery2is not consumed during cooling, the SOC1 is the same as the current SOC0. In addition, the battery control unit5aestimates an estimated value (T2, SOC2) of the battery temperature and the SOC after cooling when the cooling device3is operated by the electric power from the battery2. In this case, since the electric power of the battery2is consumed during cooling, the SOC2 is lower than the current SOC1. It should be noted that in the present embodiment, it is assumed that the estimated values of the battery temperature T1 and T2 are the same value.

InFIG.3, the deterioration sensitivity X2 at the estimated value (T2, SOC2) is lower than the deterioration sensitivity X1 at the estimated value (T1, SOC1). That is, the deterioration of the battery2can be prevented by operating the cooling device3by the electric power from the battery2rather than the electric power from the external power source10. On the other hand, inFIG.4, the deterioration sensitivity X1 at the estimated value (T1, SOC1) is lower than the deterioration sensitivity X2 at the estimated value (T2, SOC2). That is, the deterioration of the battery2can be prevented by operating the cooling device3by the electric power from the external power source10rather than the electric power from the battery2.

[Control Flows]

Next, the control flows executed by the control device5will be described with reference toFIG.5.

In step S100, the battery control unit5adetermines Whether the vehicle V is connected to the external power source10. When the vehicle V is not connected to the external power source10(NO), the process returns to step S100again and monitors until the vehicle V is connected to the external power source10. When the vehicle V is connected to the external power source10(YES), the process proceeds to step S102.

In step S102, the battery control unit5adetermines whether the battery2is in a high temperature and high SOC state. Specifically, it is determined whether the battery temperature is higher than the predetermined temperature range and the SOC is higher than the predetermined SOC range. When the battery2is not in the high temperature and high SOC state (NO), the control flows according to the present embodiment end. When the battery2is in the high temperature and high SOC state (YES), the process proceeds to step S104.

In step S104, the battery control unit5aestimates the estimated value (T1, SOC1) of the battery temperature and the SOC after cooling when the cooling device3is operated by the electric power from the external power source10, and the estimated value (T2, SOC2) of the battery temperature and the SOC after cooling when the cooling device3is operated by the electric power from the battery2. Here, the estimated value (T1, SOC1) corresponds to the “first estimated value” in the present disclosure, and the estimated value (T2, SOC2) corresponds to the “second estimated value” in the present disclosure.

Subsequently, in step S106, the battery control unit5aacquires the deterioration sensitivity X1 at the estimated value (T1, SOC1) and the deterioration sensitivity X2 at the estimated value (T2, SOC2) with reference to the deterioration sensitivity map, and the process proceeds to step S108.

In step S108, the battery control unit5acompares the deterioration sensitivity X1 and the deterioration sensitivity X2. For example, as shown inFIG.3, when the deterioration sensitivity X2 is lower than the deterioration sensitivity X1, that is, when an deterioration prevention effect in a case of operating the cooling device3by the electric power from the battery2is higher than an deterioration prevention effect in a case of operating the cooling device3by the electric power from the external power source10(YES), the process proceeds to step S110. On the other hand, for example, as shown inFIG.4, when the deterioration sensitivity X2 is equal to or higher than the deterioration sensitivity X1, the process proceeds to step S116. In step S116, the battery control unit5asends to the cooling control unit5bcommand to operate the cooling device3by the electric power from the external power source10. The cooling control unit5boperates the cooling device3by the electric power from the external power source10, and the control flows according to the present embodiment end. It should be noted that when the deterioration sensitivity X1 and the deterioration sensitivity X2 are equal in step S108, the process may proceed to step S110instead of step S116.

In step S110, the battery control unit5anotifies the user terminal20of a proposal to operate the cooling device3by the electric power from the battery2by lowering an SOC upper limit preset by the user. By notifying the user of such a proposal, it is possible to prevent the SOC upper limit of the battery2from being lowered without the user being aware of it, thereby preventing the SOC from being lowered. It should be noted that the lowering of the SOC upper limit may be a temporary lowering, or may be a lowering until the user resets the SOC upper limit, After the above proposal is notified to the user terminal20, the process proceeds to step S112.

In step S112, the battery control unit5adetermines whether the user permits the above proposal. When the user does not permit the above proposal (NO), the process proceeds to step S116described above, and the battery control unit5asends to the cooling control unit5bthe command to operate the cooling device3by the electric power from the external power source10. The cooling control unit5boperates the cooling device3by the electric power from the external power source10, and the control flows according to the present embodiment end. In this way, it is possible to select an electric power source for the cooling device according to the intention of the user. On the other hand, when the user permits the above proposal (YES), the process proceeds to step S114.

In step S114, the battery control unit5alowers the SOC upper limit of the battery2to allow the electric power of the battery2to be consumed during cooling (that is, the SOC of the battery2to be lowered). Then, the battery control unit5asends to the cooling control unit5ba command to operate the cooling device3by the electric power from the battery2. The cooling control unit5boperates the cooling device3by the electric power from the battery2, and the control flows according to the present embodiment end.

As described above, according to the present embodiment, when the vehicle V is connected to the external power source10, the deterioration sensitivity X1 and the deterioration sensitivity X2 are compared to select either the electric power from the battery2or the electric power from the external power source10to operate the cooling device3. By selecting an electric power source for the cooling device3in consideration of the deterioration sensitivity in this manner, the deterioration of the battery2can be appropriately prevented.

In addition, since the battery2is cooled by permitting the lowering of the SOC upper limit of the battery2only when the permission of the user is obtained, it is possible to prevent the SOC upper limit of the battery2from being lowered without the user being aware of it.

Although the case of maintaining the SOC of the battery2and the case of lowering the SOC of the battery2have been described in the above embodiment, it is also possible to increase the SOC by storing electric power in the battery2while the battery2is cooled by the electric power from the external power source10.

In addition toFIG.3,FIG.6is a diagram showing an estimated value (T3, SOC3) of the battery temperature and the SOC after cooling and a deterioration sensitivity X3 at the estimated value (T3, SOC3) when the cooling device3is operated by the electric power from the external power source10and electric power is stored in the battery2. When the battery temperature is lowered to the predetermined temperature range, the control device5may compare the deterioration sensitivities X1 to X3 and acquire a deterioration sensitivity (X2 inFIG.6) having the highest deterioration prevention effect. The control device5selects either the electric power from the battery2or the electric power from the external power source10based on the deterioration sensitivity having the highest deterioration prevention effect to operate the cooling device3.

Although an embodiment of the present disclosure has been described above with reference to the accompanying drawings, it is needless to say that the present disclosure is not limited to the embodiment. It is apparent to those skilled in the art that various changes and modifications can be conceived within the scope of the claims, and it is also understood that such changes and modifications naturally belong to the technical scope of the present disclosure. In addition, constituent elements in the above embodiment may be freely combined without departing from the spirit of the disclosure.

In the above embodiment, in step S108, when the deterioration sensitivity X2 is lower than the deterioration sensitivity X1, the process proceeds to step S110and step S112, and the user is notified of the proposal to operate the cooling device3by the electric power from the battery2by lowering the SOC upper limit of the battery2, but the present disclosure is not limited thereto. For example, the process may directly proceed to step S114without performing steps S110and S112, and the control device5may operate the cooling device3by the electric power from the battery2.

At least the following matters are described in the present specification. In the parentheses, the corresponding constituent elements and the like in the above embodiment are shown as an example, and the present disclosure is not limited thereto.

(1) A battery temperature adjustment system (battery temperature adjustment system1), including:a battery (battery2) configured to store electric power from an external power source (external power source10), and supply electric power to a motor (motor7) as a drive source of a vehicle (vehicle V);a cooling device (cooling device3) to which the electric power from the external power source and the electric power from the battery are selectively supplied and configured to cool the battery; anda control device (control device5) configured to control the cooling device to adjusta state of charge of the battery and a battery temperature, in which the control devicestores a deterioration sensitivity map in which a deterioration sensitivity is preset according to the state of charge and the battery temperature, or is capable of calculating a deterioration sensitivity according to the state of charge and the battery temperature, andselects, when the vehicle is connected to the external power source, either the electric power from the battery or the electric power from the external power source based on the deterioration sensitivity to operate the cooling device.

According to (1), when the vehicle is connected to the external power source, the control device selects either the electric power from the battery or the electric power from the external power source based on the deterioration sensitivity to operate the cooling device. Accordingly, since an electric power source for the cooling device can be selected in consideration of the deterioration sensitivity, the deterioration of the battery can be appropriately prevented.

(2) The battery temperature adjustment system according to (1), in whichthe control device estimatesa first estimated value (estimated value (T1, SOC1)) of the state of charge and the battery temperature after cooling when the cooling device is operated by the electric power from the external power source, anda second estimated value (estimated value (T2, SOC2)) of the state of charge and the battery temperature after cooling when the cooling device is operated by the electric power from the battery,when the vehicle is connected to the external power source, the control deviceoperates the cooling device by the electric power from the battery when the deterioration sensitivity at the second estimated value (deterioration sensitivity X2) is lower than the deterioration sensitivity at the first estimated value (deterioration sensitivity X1), andoperates the cooling device by the electric power from the external power source when the deterioration sensitivity at the first estimated value is lower than the deterioration sensitivity at the second estimated value.

According to (2), by comparing the deterioration sensitivity at the first estimated value and the deterioration sensitivity at the second estimated value to select an electric power source for the cooling device, the deterioration of the battery can be appropriately prevented.

(3) The battery temperature adjustment system according to (2), in whichwhen the deterioration sensitivity at the first estimated value is lower than the deterioration sensitivity at the second estimated value, before the cooling device is operated by the electric power from the battery, a user is notified of a proposal to operate the cooling device by the electric power from the battery.

According to (3), before the cooling device is operated by the electric power from the battery, a user is notified of a proposal to operate the cooling device by the electric power from the battery, and thus, it is possible to prevent the SOC from being lowered without the user being aware of it.

(4) The battery temperature adjustment system according to (3), in whichwhen the user permits the proposal, the control device operates the cooling device by the electric power from the battery.

According to (4), when the user permits the proposal, the control device operates the cooling device by the electric power from the battery, and thus, it is possible to lower the SOC with the permission of the user.

(5) The battery temperature adjustment system according to (3) or (4), in whichwhen the user does not permit the proposal, the control device operates the cooling device by the electric power from the external power source.

According to (5), when the user does not permit the proposal, the control device operates the cooling device by the electric power from the external power source, and thus, it is possible to select an electric power source for the cooling device according to the intention of the user.