Battery temperature control system

Abstract

To configure a system making it possible to elevate a battery temperature while suppressing increase in size regardless of configuration using a heat medium.SOLUTION: A battery temperature control system S comprises: an electrically-driven vehicle drive unit D including at least an electric motor 11 transmitting a driving torque being electric current of a battery B to a vehicle travel system; an inverter 14 controlling the electric current supplied from the battery B to the electric motor 11; and a first circulation flow path C1 allowing a cooling water to flow into the inverter 14, electrically-driven vehicle drive unit D, battery B and radiator 5, respectively in this order. Furthermore, the system comprises a switching valve V capable of adjusting a supply amount to be supplied to the battery B, of the cooling water taken out from a flow path for feeding the cooling water from the inverter 14 to the electrically-driven vehicle drive unit D out of the first circulation flow path C1.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery temperature control system.

Background Art

[0002] In an EV vehicle or the like that drives an electric motor with the current of a battery to run, a secondary battery that can be charged to the battery is used. This battery caused a decrease in the available current (electric power) as the environmental temperature decreased.

[0003] In order to eliminate such inconveniences, Patent Document 1 includes a circulation circuit that circulates oil in each of the vehicle's transaxle, battery, and oil cooler, and supplies the oil in the circulation oil path to the battery by an oil pump to enable the temperature of the battery to rise.

[0004] As a specific configuration, Patent Document 1 describes a first oil path through which the circulation circuit flows oil to the oil cooler and a second oil path through which the circulation circuit does not flow oil to the oil cooler, and two electric oil pumps are provided to flow oil through each oil path individually. Based on the temperature of the battery, the two oil pumps are selectively driven to not only raise the temperature of the battery (warm up) but also control the cooling of the battery.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As mentioned above, the batteries installed in electric vehicles experience a decrease in performance during winter when ambient temperatures drop, and therefore require a temperature increase, as described in Patent Document 1. From the perspective of raising the battery temperature, it is conceivable to utilize the heat generated when the electric motor is in operation.

[0007] However, as shown in Patent Document 1, while it is possible to raise the battery temperature using the heat generated by the electric motor when using lubricating oil or the like as a heat transfer medium, there is a concern that excessive heat from the electric motor may be supplied when the ambient temperature is high, such as in summer, and the battery needs to be cooled. This could lead to the need for a larger radiator or flow path to cool the heat transfer medium.

[0008] For these reasons, there is a need for a system that uses a heat transfer medium while suppressing the need for a large size and enabling the battery temperature to rise. [Means for solving the problem]

[0009] The characteristic configuration of the battery temperature control system according to the present invention is that it comprises a battery capable of charging and discharging, an electric vehicle drive unit including at least an electric motor that is driven and rotated by the current supplied from the battery and transmits the driving force to the vehicle's running gear, an inverter that controls the current supplied from the battery to the electric motor, and a first circulation passage that flows coolant in this order to the inverter, the electric vehicle drive unit, the battery, and the radiator, and a switching valve that can adjust the amount of coolant supplied to the battery from the passage that supplies the coolant from the inverter to the electric vehicle drive unit within the first circulation passage.

[0010] This configuration allows for the extraction of cooling water from the inverter to the electric vehicle drive unit from the first circulation path, and the adjustment of the amount of this extracted cooling water supplied to the battery by a switching valve. This allows for the adjustment of the ratio of cooling water heated by the inverter to the amount of cooling water heated by the electric vehicle drive unit. As a result, when the ambient temperature is low and the electric vehicle drive unit temperature is low, the amount of cooling water supplied to the battery heated by the inverter is increased compared to the amount of cooling water supplied to the electric vehicle drive unit, enabling a rapid rise in battery temperature. This is because reducing the amount of cooling water supplied to the electric vehicle drive unit prevents heat from being lost to the electric vehicle drive unit.

[0011] For example, in a flow path configuration that constantly supplies cooling water heated by the inverter and the electric vehicle drive unit to the battery, a flow path configuration that enhances the heat exchange efficiency of the cooling water flowing to the electric vehicle drive unit can be envisioned to enable the battery temperature to rise even when the temperature of the electric vehicle drive unit has not risen sufficiently. However, in such a flow path configuration, the amount of heat stored in the cooling water becomes excessive after the battery temperature rises, leading to a larger radiator for heat dissipation and a larger capacity pump for circulating the heat transfer medium. In contrast, in the present feature configuration, where the ratio of the amount of cooling water heated by the inverter and the amount of cooling water heated by the electric vehicle drive unit can be adjusted using a switching valve, the battery temperature can rise in a short time by adjusting the ratio, and a flow path configuration that enhances the heat exchange efficiency of the cooling water flowing to the electric vehicle drive unit is not required. Therefore, a system has been constructed that enables the battery temperature to rise while suppressing the increase in size, even though it is a configuration that uses a heat transfer medium.

[0012] Other configurations include a branch channel for extracting a portion of the cooling water flowing between the inverter and the electric motor, a heat exchange channel for connecting the cooling water, which has passed through a heat exchange section that exchanges heat between the oil circulating inside the electric motor and the cooling water flowing through the branch channel, to the upstream side of the first circulation channel relative to the battery, and a bypass channel for sending the cooling water downstream of the point where the heat exchange channel merges with the first circulation channel, wherein the switching valve may be able to switch the cooling water flowing through the branch channel to the heat exchange channel and the bypass channel.

[0013] According to this system, a switching valve directs the cooling water from the branch channel to the heat exchange channel. This transfers the heat from the oil circulating inside the electric motor to the cooling water, which is heated by the inverter's heat. The cooling water, now containing the heat from both the inverter and the electric motor, is then supplied to the battery, allowing its temperature to rise. Furthermore, during winter when the battery temperature is low, the switching valve directs the cooling water from the branch channel to the bypass channel, supplying the cooling water, now containing the heat from the inverter, to the battery, again allowing its temperature to rise.

[0014] Other configurations include a first temperature sensor for detecting the temperature of the cooling water supplied to the inverter, a second temperature sensor for detecting the temperature of the oil flowing into the heat exchange section, and a control unit for controlling the switching valve, wherein the control unit may control the switching valve based on the values ​​detected by the first and second temperature sensors.

[0015] According to this, for example, based on the detection values ​​of the first temperature sensor and the second temperature sensor, the control unit can set the ratio of the flow rate of the cooling water flowing through the bypass channel to the amount of cooling water flowing through the bypass channel to an optimal value, thereby raising the battery temperature. The temperature of the cooling water supplied to the inverter is closely related to the ambient temperature, and the temperature of the oil flowing into the heat exchange section is closely related to the temperature of the electric vehicle drive unit, making this control particularly effective in winter.

[0016] Other configurations include a first temperature sensor for detecting the temperature of the cooling water supplied to the inverter, a battery temperature sensor for detecting the temperature of the battery, and a control unit for controlling the switching valve. The control unit may enable the supply of the cooling water to the heat exchange flow path when the detected value of the battery temperature sensor is less than a first set value and the detected value of the first temperature sensor is less than a second set value, and may control the switching valve to supply the cooling water to the bypass flow path when the detected value of the battery temperature sensor is equal to or greater than the first set value, or when the detected value of the first temperature sensor is equal to or greater than the second set value.

[0017] According to this configuration, when the battery temperature sensor's detected value is below the first setpoint, and the first temperature sensor's detected value is below the second setpoint, coolant can be supplied to the heat exchange channel. This allows the heat from the inverter and the electric vehicle's drive unit to be transferred to the battery, causing the battery temperature to rise. Conversely, when the battery temperature sensor's detected value is above the first setpoint, or when the first temperature sensor's detected value is above the second setpoint, coolant is supplied to the bypass channel. This prevents excessive heat from being transferred from the electric vehicle's drive unit to the coolant, thus preventing the radiator from becoming larger. This configuration is particularly effective for summer control.

[0018] Alternatively, the following components may be integrated: a cooling module having an electric pump for circulating the cooling water, a switching valve, and a cooling channel for flowing the cooling water between the electric pump and the switching valve; the electric vehicle drive unit; and the inverter.

[0019] According to this, by integrating a cooling module having an electric pump, a switching valve, and a cooling flow path respectively, a drive unit for an electric vehicle, and an inverter, it is easier to handle compared to a configuration in which these are separately arranged, and it becomes possible to shorten the flow path for sending cooling water. Further, since the cooling module includes an electric pump, a switching valve, and a cooling flow path, for example, the assembly process can be simplified compared to a configuration in which these are individually attached to the drive unit for an electric vehicle, and maintenance such as replacement of the switching valve can be easily performed.

Brief Description of the Drawings

[0020] [Figure 1] It is a plan view showing an outline of the configuration of an EV vehicle. [Figure 2] It is a side view of a drive unit for an electric vehicle. [Figure 3] It is a diagram showing the configuration of a battery temperature control system. [Figure 4] It is an enlarged cross-sectional view of the drive unit as seen from the direction along the rotation axis core of the electric motor so as to show the flow paths of cooling water and oil. [Figure 5] It is a cross-sectional view of the drive unit as seen from the direction perpendicular to the rotation axis core of the electric motor so as to show the flow paths of cooling water and oil. [Figure 6] It is a block circuit diagram of a control configuration. [Figure 7] It is a flowchart of winter control. [Figure 8] It is a flowchart of summer control.

Modes for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described based on the drawings. 〔Basic Configuration〕 As shown in Figure 1, an electric vehicle (hereinafter referred to as EV vehicle A) is configured as a vehicle by having a vehicle body 1 equipped with multiple wheels 2, a rechargeable battery B (secondary battery: indicated as "Batt" in the drawing) and an electric vehicle drive unit D that drives the wheels 2 with the current supplied from the battery B. Examples of EV vehicle A include automobiles equipped with a motor as a driving source (hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), battery electric vehicle (BEV), fuel cell electric vehicle (FCEV), etc.).

[0022] This EV vehicle A is equipped with a charging unit 3 that supplies current to charge the battery B, an air conditioning unit 4 (labeled "HVAC" in the drawing) that controls the interior temperature, and a radiator 5. Although not shown in the drawing, the vehicle body 1 is equipped with seats, a steering wheel, an accelerator pedal, etc.

[0023] As shown in Figure 1, EV vehicle A has a radiator 5 located at the front end (left end in Figure 1) of the vehicle body 1. The radiator 5, electric vehicle drive unit D, air conditioning unit 4, and battery B are arranged in this order in the region along the front to rear of the vehicle body 1. The battery B has a structure in which multiple cells are stacked and housed in a package (not shown). The battery B is located at the bottom of the vehicle body 1, with a portion overlapping with the air conditioning unit 4. The radiator 5 is equipped with an electric radiator fan (not shown) that blows cooling air.

[0024] In EV vehicle A, the layout of the radiator 5, the electric vehicle drive unit D, the air conditioning unit 4, and the battery B is not limited to that shown in Figure 1, and may be in any relative position. In this EV vehicle A, AC current from an external power source such as commercial power is converted to DC current by the charging unit 3 and used to charge the battery B.

[0025] The vehicle body 1 is equipped with a driving control device (not shown) configured as an ECU to control the current supplied to the electric vehicle drive unit D. This driving control device controls the inverter 14 shown in Figures 1 to 3 according to the amount the accelerator pedal is pressed, and supplies the necessary current to the electric vehicle drive unit D to enable driving.

[0026] [Drive unit for electric vehicles] As shown in Figures 2 and 3, the electric vehicle drive unit D is equipped with an inverter 14 (labeled "INV" in the drawings) on the top surface of the unit case 10 and a cooling module 15 on the rear surface of the unit case 10. In this way, the electric vehicle drive unit D, the inverter 14 and the cooling module 15 are integrated. As shown in Figure 3, the electric vehicle drive unit D houses an electric motor 11, a reduction gear 12 (speed reducer), and a differential gear 13 in a single unit case 10 (an example of a case).

[0027] The electric vehicle drive unit D reduces the driving force of the electric motor 11 using a reduction gear 12, transmits it to the output shaft 13a via a differential gear 13, and transmits this driving force from the output shaft 13a to the wheels 2.

[0028] [Battery temperature control system] Battery B, as a secondary battery, undergoes chemical reactions during charging and discharging. The heat generated during charging and discharging causes its temperature to rise, and its performance changes with temperature. Battery B's performance deteriorates when the temperature is not appropriate. As shown in Figure 3, EV vehicle A is equipped with a battery temperature control system S to maintain battery B at an appropriate temperature.

[0029] The battery temperature control system S includes a first circulation channel C1 that circulates coolant L1 in the order of inverter 14, electric motor 11 (electric vehicle drive unit D), battery B, and radiator 5, and a second circulation channel C2 that circulates oil L2, which functions as lubricant inside the electric vehicle drive unit D, in the order of main oil passage 31, oil cooler 7 (labeled "O / C" in the drawing), distribution oil passage 32, shaft oil passage 33, and case wall oil passage 34.

[0030] In Figures 3 and 5, the first circulation channel C1 through which the cooling water L1 flows is shown as a solid line, and the second circulation channel C2 through which the oil L2 flows is shown as a dashed line.

[0031] The coolant L1 is assumed to be water containing components such as ethylene glycol, similar to the coolant used to cool internal combustion engines, but it may also contain components other than ethylene glycol. The oil L2 should function as a lubricant that lubricates the reduction gear 12 and differential gear 13 of the electric vehicle drive unit D.

[0032] The first circulation channel C1 controls the temperature of the battery B by flowing coolant L1 through a channel formed in the battery B's package. In particular, the control mode described later mainly explains the temperature rise of the battery B at low temperatures. If the temperature of the battery B rises above an appropriate value, the following control measures are taken to lower the temperature of the battery B: the flow rate of coolant L1 in the first circulation channel C1 is increased, the airflow rate of the cooling air is increased by increasing the driving speed of the radiator fan, the opening degree of the grill shutter 5a is increased, and the temperature of the coolant L1 is lowered by increasing the heat dissipation by the radiator 5.

[0033] [Battery temperature control system: First circulation channel] As shown in Figure 3, the first circulation channel C1 includes an inverter supply channel 21, a unit supply channel 22, a unit channel 23, a recovery channel 24, and a reduction channel 25.

[0034] The inverter supply channel 21 is configured as a channel for supplying coolant L1 from the radiator 5 to the inverter 14, and is equipped with an electric water pump P1 (an example of an electric pump) within the channel of this inverter supply channel 21. The unit supply channel 22 supplies the coolant L1 sent from the inverter 14 to the electric vehicle drive unit D.

[0035] The unit flow path 23 supplies cooling water L1 from the unit supply side flow path 22 to the internal flow path 23a of the unit case 10 of the electric vehicle drive unit D and to the internal flow path 23b of the slot of the electric motor 11 (see also Figure 4). Details of the internal flow paths of this electric vehicle drive unit D will be described later.

[0036] The recovery channel 24 supplies the coolant L1 sent from the unit case 10 (through the internal channel 23a and the internal channel 23b in the slot) to the battery B. The return channel 25 returns the coolant L1 sent from the battery B to the radiator 5.

[0037] As shown in Figure 3, the first circulation channel C1 has a branch channel 26 that takes out a portion of the cooling water L1 flowing in the unit supply channel 22. Downstream of this branch channel 26 is an electromagnetic switching valve V (labeled "3Way" in the drawing) configured as a three-way valve. The three-way valve in this embodiment is a rotary valve or the like, consisting of one inlet and two outlets.

[0038] As shown in Figure 2, the cooling module 15 houses a water pump P1, a switching valve V, and passages for flowing cooling water L1 between them (inverter supply side passage 21, unit supply side passage 22, branch passage 26, bypass passage 28, etc.).

[0039] Because this configuration includes the cooling module 15, the cooling module 15 can be assembled separately from the electric vehicle drive unit D, and by connecting them, the assembly of the cooling water L1 passage and the oil L2 passage can be facilitated.

[0040] Furthermore, downstream of the switching valve V, there is a heat exchange channel 27 through which the cooling water L1 from the branch channel 26 merges with the recovery channel 24 via the oil cooler 7 which acts as a heat exchanger, and a bypass channel 28 through which the cooling water L1 from the branch channel 26 merges with the recovery channel 24 downstream of the point where the cooling water L1 is supplied from the heat exchange channel 27.

[0041] The switching valve V is configured to allow setting the ratio of the flow rates of cooling water L1 from the branch passage 26 to the heat exchange passage 27 and the bypass passage 28. Therefore, it is also possible to supply the battery B with cooling water L1 at an intermediate temperature between the temperature of the cooling water L1 flowing through the heat exchange passage 27 and the temperature of the cooling water L1 flowing through the bypass passage 28.

[0042] In this manner, the first circulation channel C1 dissipates heat from the coolant L1 via the radiator 5, and cools the electric motor 11 by circulating this coolant L1 inside the electric vehicle drive unit D. At the same time, the coolant L1 stores the heat from the electric motor 11 and is sent to the recovery channel 24, which is then supplied to the battery B downstream of the recovery channel 24.

[0043] Furthermore, the first circulation channel C1 supplies cooling water L1 from the branch channel 26 to the oil cooler 7 via the heat exchange channel 27 through the switching valve V, thereby dissipating heat from the oil L2 flowing through the second circulation channel C2. At the same time, the cooling water L1 stores the heat from the oil L2 flowing through the second circulation channel C2 and merges with the recovery channel 24. In addition, the first circulation channel C1 supplies cooling water L1 from the branch channel 26 to the bypass channel 28 via the switching valve V, thereby merging this cooling water L1 into the recovery channel 24 downstream of the heat exchange channel 27.

[0044] Furthermore, in winter, when the ambient temperature is low and the electric vehicle drive unit D is at a low temperature, the switching valve V is activated to reduce the flow rate of cooling water L1 flowing from the branch passage 26 to the heat exchange passage 27, and to increase the flow rate of cooling water L1 flowing through the bypass passage 28 of the branch passage 26, thereby enabling a rapid temperature rise of the battery B.

[0045] [Battery temperature control system: Second circulation channel] As shown in Figure 3, the second circulation channel C2 includes a main oil passage 31, a distribution oil passage 32, an oil passage inside the shaft 33, and a case wall oil passage 34.

[0046] The main oil passage 31 is formed as a flow path that supplies oil L2 stored in the storage section 10a at the bottom of the unit case 10 to the oil cooler 7, and an electric oil pump P2 is provided within the flow path of this main oil passage 31.

[0047] As mentioned above, the oil cooler 7 enables heat dissipation from the oil L2 by transferring the heat from the oil L2 flowing through the second circulation passage C2 to the coolant L1, and this heat dissipation increases the temperature of the coolant L1 passing through the oil cooler 7.

[0048] The distribution oil passage 32 distributes the oil L2 that has passed through the oil cooler 7 to the shaft internal oil passage 33 and the case wall oil passage 34 (see Figures 4 and 5). The shaft internal oil passage 33 is formed inside the shaft 11a of the electric motor 11, and the flow of oil L2 cools the rotor 11b. The oil L2 that flows through this shaft internal oil passage 33 is ultimately supplied to the reduction gear 12 and the differential gear 13, lubricating them. The case wall oil passage 34 is formed in the unit case 10 and cools the unit case 10.

[0049] [Drive unit flow path configuration] As shown in Figures 3 to 5, the electric motor 11 comprises a rotor 11b that rotates integrally with the shaft 11a, and a stator 11c arranged in the region surrounding the rotor 11b. The rotor 11b is equipped with permanent magnets (not shown) inside a yoke made of laminated electromagnetic steel sheets. Furthermore, as shown in Figures 4 and 5, the stator 11c has a coil 11e formed by winding a wire made of a good conductor coated with an insulating film around a plurality of slots 11d formed in the fixed-side yoke made of laminated electromagnetic steel sheets.

[0050] As shown in Figures 4 and 5, the internal case flow path 23a consists of multiple tunnel-shaped flow paths formed within the wall thickness of the unit case 10, in a position parallel to the rotation axis of the electric motor 11. Cooling of the unit case 10 is achieved by supplying cooling water L1 from the unit supply side flow path 22 to this internal case flow path 23a.

[0051] As shown in Figures 4 and 5, the slot channel 23b is formed as a channel that electrically insulates the coil 11e from the rotor 11b by the insulating member 8 so as to cover the coil 11e housed in the slot 11d. Cooling of the coil 11e is achieved by the flow of cooling water L1 through the slot channel 23b formed by this insulating member 8.

[0052] Furthermore, the cooling water L1 that flows through multiple internal case channels 23a and multiple internal slot channels 23b merge and flow into the recovery channel 24, thus forming a flow path.

[0053] [Battery temperature control system: Sensors] As shown in Figure 3, the battery temperature control system S includes a first temperature sensor S1 for detecting the temperature of the cooling water L1 near the inlet side of the inverter 14 in the inverter supply side flow path 21, and a second temperature sensor S2 for detecting the temperature of the oil L2 upstream of the oil cooler 7 in the distribution oil passage 32. It also includes a battery temperature sensor Sb for detecting the temperature of the battery B and an ambient temperature sensor Sa for detecting the ambient temperature.

[0054] As shown in Figure 3, the radiator 5 is equipped with a plurality of grill shutters 5a on the intake side (front side) and a shutter control unit 16 that electrically controls the opening degree of these grill shutters 5a.

[0055] As shown in Figure 6, the battery temperature control system S includes a control unit 17. This control unit 17 receives the detection values ​​from the first temperature sensor S1, the second temperature sensor S2, the ambient temperature sensor Sa, and the battery temperature sensor Sb, and outputs control signals to the switching valve V, the shutter control unit 16, the water pump P1, and the oil pump P2.

[0056] [Control Mode] The control unit 17 is configured as an ECU by using a microprocessor and a DSP (Digital Signal Processor), and by including non-volatile memory for storing information. The control unit 17 stores in its non-volatile memory the program for implementing the control, the target value for maintaining the temperature of the battery B at an optimal value, or the threshold value that serves as the criterion for switching the flow path by the switching valve V.

[0057] The control unit 17 determines the season by acquiring the temperature of the environment in which the vehicle body 1 is located, as detected by the ambient temperature sensor Sa. In this embodiment, an example is described in which winter control is performed as shown in the flowchart of Figure 7 during winter, and summer control is performed as shown in the flowchart of Figure 8 during summer.

[0058] [Control mode: Winter control] As shown in the flowchart in Figure 7, winter control acquires the detected value (T1) from the first temperature sensor S1 and the detected value (T2) from the second temperature sensor S2, and sets the winter threshold (Tx, e.g., 5°C) (steps #101 and #102).

[0059] Next, the difference between the detected value (T1) and the detected value (T2) (T2-T1) is compared with the winter threshold (Tx). If it is determined that the difference is smaller than (or equal to) the winter threshold (Tx) (Yes in step #103), the bypass channel 28 is opened to directly flow the cooling water L1, whose temperature has risen in the inverter 14, into the recovery channel 24, thereby raising the temperature of the battery B (step #104).

[0060] This #104 step of control suppresses the inconvenience of some of the heat from the cooling water L1 being lost in the electric vehicle drive unit D when the temperature of the electric vehicle drive unit D is low, such as immediately after the vehicle starts running, and cooling water L1 is supplied to the unit flow path 23. In addition, the cooling water L1, whose temperature has risen by passing through the inverter 14, is supplied to the battery B, efficiently heating the battery B and enabling a rapid temperature rise.

[0061] In contrast, if it is determined that the difference is greater than the winter threshold (Tx) (No. in step #103), the bypass passage 28 is closed, thereby transferring heat from the oil L2 to the coolant L1 in the oil cooler 7, raising the temperature of the coolant L1 flowing through the recovery passage 24. As a result, the temperature of the battery B is raised using the heat from the inverter 14 and the drive unit D for the electric vehicle (step #105).

[0062] In this winter control system, when aiming to raise the temperature of battery B, the opening degree of the grill shutter 5a is set low, and the flow rate of the coolant L1 supplied to the radiator 5 is reduced by suppressing the drive speed of the water pump P1, thereby efficiently raising the temperature of the coolant L1.

[0063] Alternatively, instead of controlling step #103 in the flowchart of Figure 7, it is possible to perform the calculation (T1-T2) and set the control mode to compare the difference with a predetermined threshold, thereby performing the control in steps #104 and #105. In this case, when using the winter threshold Tx, it is possible to reverse the inequality relationship or use thresholds with different values.

[0064] [Control mode: Summer control] As shown in the flowchart in Figure 8, in summer control, the detected value (Tb) of the battery temperature sensor Sb is acquired, the first summer setpoint (Ty: an example of the first setpoint, e.g., 45°C) is set, and the detected value (Tb) and the first summer setpoint (Ty) are compared (steps #201 to #203).

[0065] If the comparison in step #203 determines that the detected value (Tb) is less than (or equal to) the first summer setting value (Ty) (Yes in step #203), the detected value (T1) from the first temperature sensor S1 is obtained, the second summer setting value (Tz: an example of the second setting value, e.g., 60°C) is set, and the detected value (T1) and the second summer setting value (Tz) are compared (steps #204 to #206).

[0066] If this comparison determines that the detected value (T1) is smaller than (or equal to) the second summer setting value (Tz) (Yes in step #206), the bypass passage 28 is closed, allowing heat to be transferred from the oil L2 to the coolant L1 in the oil cooler 7, thereby increasing the temperature of the coolant L1 flowing into the recovery passage 24 and raising the temperature of the battery B (step #207).

[0067] In contrast, if step #203 determines that the detected value (Tb) is greater than the first summer setting value (Ty), or if step #206 determines that the detected value (T1) is greater than the second summer setting value (Tz), the bypass channel 28 is opened, allowing the coolant L1 whose temperature has risen in the inverter 14 to flow directly into the recovery channel 24, thereby raising the temperature of the battery B without causing an excessive temperature rise. As a result, it becomes possible to miniaturize the radiator 5.

[0068] In this summer control system, steps #203 and #206 compare different setpoints. However, it is possible to configure the system to set equal setpoints in steps #203 and #206 and then compare them. Alternatively, steps #201-#204 and steps #204-#206 can be swapped.

[0069] Furthermore, in summer control, the drive speed of the water pump P1 is generally increased compared to winter control. However, when increasing the temperature of battery B, a process to reduce the drive speed of the water pump P1 is performed in parallel.

[0070] [Effects of the Embodiment] In the electric vehicle drive unit D, heat generated internally is lost through convection and radiation from the surface of the unit case 10, and also lost when lubricating oil is discharged. In contrast, as shown in Figures 5 and 6, by flowing cooling water L1 through the internal flow path 23a formed in the unit case 10 and the internal flow path 23b formed in the slot of the electric motor 11, it is possible to store a large portion of the heat that would have been lost from the surface of the unit case 10 in the cooling water L1. Furthermore, by flowing oil L2 through the case wall oil passage 34 formed in the unit case 10, it is possible to store a large portion of the heat that would have been lost from the surface of the unit case 10 in the oil L2.

[0071] By using cooling water L1 and oil L2 in this manner, and by supplying the oil L2 inside the unit case 10 to the oil cooler 7 from the main oil passage 31, and then supplying it to the cooling water L1 in the heat exchange passage 27 at the oil cooler 7, the heat generated inside the unit case 10 is stored in the cooling water L1 without being wasted, thereby achieving an efficient temperature rise of the battery B.

[0072] In this case, if the amount of heat stored in the heat transfer medium is increased in order to raise the temperature of the battery B in a short time using a heat transfer medium during winter, for example, if the flow path is not switched by a switching valve V as in the embodiment described above, then when the ambient temperature is high, such as in summer, the amount of heat stored in the heat transfer medium will be excessive, requiring a configuration that leads to a larger radiator 5 for heat dissipation.

[0073] In contrast, as in the embodiment described above, by switching the switching valve V, it is possible to select between a standard heating mode in which the cooling water L1 heated by the inverter 14 and the electric motor 11 is supplied to the battery B, and a rapid heating mode in which the cooling water L1 heated by the inverter 14 is supplied to the battery B in situations where the heat of the electric motor 11 cannot be utilized, such as before the temperature of the electric motor 11 rises. This suppresses the inconvenience of an excessive amount of heat being stored in the heat transfer medium, and prevents the need to increase the size of the radiator 5 and the capacity of the pump that circulates the heat transfer medium.

[0074] In winter control, by controlling the switching valve V, the cooling water L1 heated by the inverter 14 is merged from the bypass channel 28 to the recovery channel 24. This suppresses the inconvenience of the electric vehicle drive unit D losing some of the heat from the cooling water L1, while supplying the cooling water L1 whose temperature has risen by the inverter 14 to the battery B, thereby enabling a rapid rise in the temperature of the battery B.

[0075] Furthermore, in summer control mode, when a temperature rise of battery B is required, the system utilizes the heat inside the unit case 10 to raise the temperature of battery B. Additionally, if the temperature of battery B fluctuates slightly within an appropriate range, the system maintains the flow of coolant L1 from the switching valve V to the heat exchange passage 27 while adjusting the amount of coolant L1 flowing through the first circulation passage C1. This allows for a balance between heat dissipation from the radiator 5 and the heat generated by the electric vehicle drive unit D.

[0076] By maintaining the temperature of battery B optimally in this way, the necessary current is supplied to the electric motor 11, enabling the vehicle to run without causing a decrease in battery performance. Furthermore, because the decrease in battery performance is suppressed, the necessary current can be supplied to the air conditioning unit 4 when air conditioning is performed using the air conditioning unit 4.

[0077] [Another embodiment] The present invention may also be configured as follows, in addition to the embodiments described above (parts having the same functions as the embodiments are given the same numbers and reference numerals as the embodiments).

[0078] (a) Although the embodiment shows the arrangement of the radiator 5, the electric vehicle drive unit D, the air conditioning unit 4, and the battery B, the arrangement is not limited to that shown in the embodiment and can be arranged arbitrarily.

[0079] (b) The passages for the cooling water L1 or the oil L2 inside the electric vehicle drive unit D can be configured in accordance with the structure of the electric vehicle drive unit D and the structure of the electric motor 11, and the arrangement of sensors is not limited to the arrangement described in the embodiment and can be placed in any position.

[0080] (c) In order to further increase the temperature of battery B, it is possible to house the electric vehicle drive unit D in an insulated case or cover it with insulating material.

[0081] (d) The switching valve V is not limited to a three-way valve, and may be an on-off valve that opens and closes the bypass passage 28. Alternatively, a four-way valve may be provided at the connection point between the unit supply passage 22 and the branch passage 26.

[0082] (e) The cooling water channel formed inside the unit case 10 in the above-described embodiment is just one example; any channel that allows cooling water L1 to circulate inside the unit case 10 is acceptable. Furthermore, the cooling module 15 does not need to be integrated into the unit case 10.

[0083] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, provided that no inconsistencies arise. Moreover, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0084] This invention can be used in battery temperature control systems. [Explanation of Symbols]

[0085] 5. Radiator 7. Oil cooler 10 Unit Case (Case) 11 Electric motor 14 Inverters 15 Cooling Modules 17 Control Unit 26 Branching channel (channel) 27 Heat exchange channel 28 Bypass channel B Battery C1 First circulation channel C2 Second circulation channel D. Drive unit for electric vehicles L1 cooling water L2 Oil P1 Water Pump (Electric Pump) S Battery Temperature Control System S1 First temperature sensor S2 Second temperature sensor Sb Battery Temperature Sensor Ty Summer 1st setting (1st setting) Tz Summer 2nd setting value (2nd setting value) V-type switching valve

Claims

1. A rechargeable battery, An electric vehicle drive unit including at least an electric motor that rotates using current supplied from the battery and transmits the rotational force to the vehicle's drive system, An inverter that controls the current supplied from the battery to the electric motor, The inverter, the electric vehicle drive unit, the battery, and the radiator are each provided with a first circulation path that flows coolant in this order, A battery temperature control system comprising a switching valve capable of adjusting the supply amount of the cooling water taken from the first circulation channel that supplies the cooling water from the inverter to the electric vehicle drive unit, to the battery.

2. A branch channel for extracting a portion of the cooling water flowing between the inverter and the electric motor, A heat exchange channel is provided to connect the cooling water, which has passed through a heat exchange section that exchanges heat between the oil circulating inside the electric motor and the cooling water flowing through the branch channel, to the upstream side of the first circulation channel of the battery, The first circulation channel includes a bypass channel that sends the cooling water downstream from the point where the heat exchange channel merges, The battery temperature control system according to claim 1, wherein the switching valve is capable of switching the cooling water flowing through the branch channel between the heat exchange channel and the bypass channel.

3. A first temperature sensor for detecting the temperature of the cooling water supplied to the inverter, A second temperature sensor for detecting the temperature of the oil flowing into the heat exchange section, The system comprises a control unit that controls the switching valve, The battery temperature control system according to claim 2, wherein the control unit controls the switching valve based on the detected values ​​of the first temperature sensor and the second temperature sensor.

4. A first temperature sensor for detecting the temperature of the cooling water supplied to the inverter, A battery temperature sensor for detecting the temperature of the aforementioned battery, The system comprises a control unit that controls the switching valve, The battery temperature control system according to claim 2, wherein the control unit enables the supply of the cooling water to the heat exchange channel when the detected value of the battery temperature sensor is less than a first set value and the detected value of the first temperature sensor is less than a second set value, and controls the switching valve to supply the cooling water to the bypass channel when the detected value of the battery temperature sensor is equal to or greater than the first set value, or when the detected value of the first temperature sensor is equal to or greater than the second set value.

5. The battery temperature control system according to claim 1, wherein a cooling module having an electric pump for circulating the cooling water, a switching valve, and a cooling channel for flowing the cooling water between the electric pump and the switching valve, the electric vehicle drive unit, and the inverter are integrated.

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