JP2006109542A - Power unit for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent a specified unit cell from deteriorating by lessening the temperature difference among battery modules in condition that it stops a vehicle. <P>SOLUTION: A power unit for a vehicle is equipped with a battery module 2, a holder case 1, a fan 3 for compulsively blasting air to the holder case 1, and a control circuit 4 which controls the operation of the fan 3. The holder case 1 is equipped with a switching mechanism 6 which is switched into an entire blasting position to blast air to the whole of the battery module 2 and a central blasting position to blast a larger quantity of air than that at both ends to the central part of the battery module 2 or to blast air only to the central part. The control circuit 4 controls both the operation of the fan 3 and the changeover of the switching mechanism 6, and it is equipped with a stop sensor which detects the stoppage of the vehicle. The control circuit 4 puts the switching mechanism 6 in the entire blasting position in the running state of the vehicle, and switches the switching mechanism 6 into the central blasting position to operate the fan 3 in condition that the vehicle is to be stopped thereby cooling the central position of the battery module 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply device that supplies power to a motor that drives a vehicle, and more particularly to a power supply device that can make the temperature of a battery module uniform while the vehicle is stopped.

  A power supply device used for the power supply of a motor that runs a vehicle is used in an extremely severe environment. For this reason, the temperature of the battery built in the power supply apparatus may become quite high. A battery has a characteristic that self-discharge becomes intense and easily deteriorates at a high temperature. In particular, since a vehicular power supply apparatus uses a large number of large-capacity batteries, the amount of heat generated by self-discharge at a high temperature is extremely large, and the probability of thermal runaway increases.

In order to prevent the battery temperature from becoming abnormally high, the power supply device performs forced cooling by operating the fan when the battery temperature becomes higher than the set temperature. However, when the ignition switch is turned off and the vehicle is stopped, the control circuit for controlling the operation of the fan does not operate, and in this state, the battery temperature may become abnormally high. In order to eliminate this drawback, a power supply device that cools a battery in a vehicle that stops the vehicle by turning off an ignition switch has been developed (see Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 2001-190001 JP 2004-47363 A

  Patent Document 1 describes a vehicle power supply device that, when the vehicle is stopped and the ignition switch is turned off, drives the fan to forcibly blow the battery when the battery temperature rises. Further, cited document 2 describes a power supply device having a structure capable of opening and closing a holder case containing a battery. This power supply device opens a holder case when the vehicle is stopped and naturally ventilates the holder case to cool the battery.

  Since the power supply device described in these cited references cools the battery while the vehicle is stopped, it is possible to prevent an abnormal temperature rise of the battery in the stopped state. However, in the power supply device of the cited document 1, when the battery is cooled to the set temperature and the operation of the fan is stopped, a temperature difference is partially generated in the battery. In particular, since the power supply device for a vehicle connects a plurality of unit cells in a straight line and houses a long and narrow battery module in a holder case, the temperature of the central portion of the battery module increases. This is because the both end portions of the battery module are naturally cooled more effectively than the central portion when the fan is stopped. Since both end portions of the battery module are fixed with electrode terminals and bus bars of metal plates, these are radiated and cooled. On the other hand, the central portion of the long battery module is hardly dissipated if air is no longer blown. For this reason, the temperature of the unit cell of the battery module is considerably higher than the unit cells at both ends.

  Moreover, the temperature of the center part of a long battery module also becomes high also in the power supply device of the cited reference 2. This is because, in a state where the holder case is opened and naturally ventilated, both end portions of the battery module are easily cooled, and the central portion is difficult to cool effectively.

  The temperature difference between the unit cells affects the amount of self-discharge of the battery and causes variations in the remaining capacity. In addition, the deterioration of the high-temperature unit cell increases, and the charge capacity varies. If the remaining capacity or the charge capacity varies, the specific unit cell is overdischarged or easily overcharged, and the specific unit cell is rapidly deteriorated to shorten its life.

  The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to provide a power supply device for a vehicle that can effectively prevent deterioration of a specific unit cell by reducing a temperature difference between battery modules while the vehicle is stopped.

  The power supply device for a vehicle according to the present invention includes a battery module 2 in which a plurality of unit cells are connected in a straight line, a holder case 1 that houses the plurality of battery modules 2, and a battery that is forcedly blown to the holder case 1. A fan 3 for cooling the module 2 and a control circuit 4 for controlling the operation of the fan 3 are provided. The holder case 1 blows a larger amount of air to the central part of the battery module 2 than to the whole blowing position compared to the whole blowing position, or to the central part of the battery module 2, or only to the central part. A switching mechanism 6 for switching to a central blowing position for blowing air is provided. The control circuit 4 controls both the operation of the fan 3 and the switching of the switching mechanism 6 and includes a stop sensor that detects the stop of the vehicle. The control circuit 4 operates the fan 3 by switching the switching mechanism 6 from the entire blowing position to the central blowing position when the vehicle is stopped, and when the vehicle is stopped, the switching circuit 6 is switched from the entire blowing position to the central blowing position. 3, the air is blown to the center of the battery module 2 to cool the center of the battery module 2.

  In the vehicle power supply device of the present invention, the stop sensor of the control circuit 4 can detect the stop of the vehicle by detecting the OFF state of the ignition switch.

  In the vehicle power supply device according to the present invention, the control circuit 4 detects the temperature difference between the central portion and both end portions of the battery module 2 in a state where the vehicle is stopped, and the detected temperature difference is larger than the set temperature difference. The fan 3 can be operated, and the switching mechanism 6 can be used as the central air blowing position to cool the air by blowing air to the central portion of the battery module 2.

  In the power supply device for a vehicle of the present invention, the control circuit 4 can stop the operation of the fan 3 by detecting that the temperature of the central portion of the battery module 2 is lower than the temperatures of both end portions.

  In the vehicle power supply device of the present invention, the switching mechanism 6 can be a flap 7 disposed in the duct 5 of the holder case 1.

  The power supply device for a vehicle according to the present invention has a feature that it is possible to effectively prevent a specific unit cell from deteriorating by reducing the temperature difference between the battery modules while the vehicle is stopped. In the power supply device for a vehicle according to the present invention, the holder case is provided with a switching mechanism for switching a blowing position of air to be blown to the battery module. In the state where the entire module is blown and the vehicle is stopped, the switching mechanism is switched to the central blowing position, and a larger amount of air is blown to the central part of the battery module than the both ends, or only to the central part. Because. Since the power supply device with this structure blows a large amount of air to the center of the battery module when the vehicle is stopped, it effectively cools the center of the battery module, which is particularly prone to rise in temperature. The difference can be reduced. Thus, the power supply device of the present invention that can reduce the temperature difference between the battery modules even when the vehicle is stopped can effectively prevent the specific unit cell from deteriorating.

  Embodiments of the present invention will be described below with reference to the drawings. However, the following embodiment exemplifies a power supply device for a vehicle for embodying the technical idea of the present invention, and the present invention does not specify the power supply device as follows.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The power supply device for a vehicle shown in FIGS. 1 to 6 is a hybrid car that drives wheels by both an engine and a motor, an electric vehicle that runs on a motor without being mounted with an engine, or a motor that is driven by a fuel cell. Installed in fuel cell vehicles.

  The power supply device mounted on the hybrid car is controlled by the control circuit 4 to supply electric power to a running motor that runs the automobile. The control circuit 4 controls charging / discharging of the power supply device and holds the battery at a predetermined remaining capacity. The control circuit 4 also controls the fan 3 that cools the battery of the power supply device to cool the battery to the set temperature range.

  The power supply device shown in the figure includes a battery module 2 in which a plurality of unit cells are connected in a straight line, a holder case 1 that houses the plurality of battery modules 2, and a forced blow to the holder case 1 to cool the battery module 2. And a control circuit 4 that controls the operation of the fan 3.

  The battery module 2 shown in the figure is formed by connecting cylindrical battery unit cells in a straight line so that the overall shape is an elongated cylindrical shape. The unit cell is a nickel-hydrogen battery. However, the unit cell may be a lithium ion secondary battery or a nickel-cadmium battery. The battery module 2 does not specify a unit cell connected in series as a cylindrical battery. A square battery can also be used as the unit cell. A battery module in which a unit cell is a square battery has an elongated quadrangular prism shape. The battery module 2 is preferably formed by connecting 4 to 6 unit cells in a straight line in series. However, the battery module can also connect three or less unit cells or seven or more unit cells in a straight line in series.

  The battery module 2 has electrode terminals 2A fixed at both ends. The electrode terminal 2 </ b> A is positioned in a plane including the central axis of the battery module 2 and is fixed in a horizontal posture parallel to the upper surface and the lower surface of the holder case 1. The electrode terminals 2A are connected in series via a bus bar (not shown). Accordingly, a connection hole (not shown) for connecting the bus bar is provided.

  The plurality of battery modules 2 are stored in the holder case 1 in a parallel posture, with the ends of adjacent battery modules 2 positioned in a plane orthogonal to the central axis of the battery module 2. Adjacent battery modules 2 are connected in series by connecting ends located on the same plane with bus bars. In other words, the bus bar is connected to the electrode terminals 2A at both ends, and the battery module 2 is housed in the holder case 1 in such a posture that both ends are positioned on the same plane.

  In the illustrated power supply apparatus, a plurality of battery modules 2 are arranged in the same horizontal plane, and further arranged in two upper and lower stages and stored in a holder case 1. The power supply device shown in FIGS. 1 and 2 can be mounted on the vehicle in a horizontal posture as shown in these drawings, or can be mounted on the vehicle in a vertical posture rotated 90 degrees from the posture shown in the drawings. .

  The holder case 1 has a structure in which air is blown in a direction orthogonal to the battery modules 2 to cool all the battery modules 2. A state in which air is blown into the holder case 1 is shown in FIGS. The holder case 1 of FIG. 7 is provided with an air inflow path 11 along the upper and lower surfaces, and an air discharge path 12 in the middle. The holder case 1 of FIG. 8 is provided with an inflow path 11 in the middle and with discharge paths 12 along both the upper and lower sides. The holder case 1 in FIG. 9 is provided with an inflow path 11 along the upper surface and a discharge path 12 along the lower surface. The inflow path 11 is connected to the suction duct 5A. The holder case 1 is provided with a cooling gap 13 that allows air for cooling the battery to pass between the surface of the battery module 2 and the inner surface of the holder case 1. The cooling gap 13 is connected to the inflow path 11 and the discharge path 12, and the air supplied to the inflow path 11 is discharged from the cooling gap 13 to the discharge path 12 to cool the battery module 2. The holder case 11 cools the battery 2 by causing the air in the inflow path 11 to flow from the cooling gap 13 to the discharge path 12.

  The holder case 1 supports both ends and the middle of the battery module 2 and accommodates the battery module 2 therein. Support recesses 14 that support both ends of the battery module 2 are provided on the side walls. The support recess 14 has a shape along the outer shape of the battery module 2 so as to fit the end of the battery module 2. The support recess 14 in the figure is semicircular and has a cylindrical battery module 2 fitted therein.

  The holder case 1 is provided with a support wall 15 that supports the middle of the battery module 2. The support wall 15 is plate-shaped and supports the battery module 2 by sandwiching it vertically. The holder case 1 shown in the figure divides the battery module 2 into three regions consisting of both end portions and a central portion, and a support wall 15 is provided at the boundary between the central portion and both end portions. The pair of support walls 15 disposed on both sides of the central portion of the battery module 2 are disposed in parallel postures. The battery module 2 has a center portion between the pair of support walls 15 and both end portions outside the support walls 15. The central portion of the battery module 2 partitioned by the support wall 15 is a portion that is not effectively cooled while the fan 3 is stopped. The battery module 2 shown in the figure has a central portion that is about 30% of the total length. However, the central portion of the battery module 2 may be 15 to 80%, preferably 20 to 60%, more preferably 20 to 50% of the total length.

  The support wall 15 holds the battery module 2 in place by sandwiching the battery module 2 up and down. The support wall 15 is provided with a fitting recess 15 a having a shape along the surface of the battery module 2 on the side edge facing the battery module 2. Since the battery module 2 is cylindrical in the figure, the fitting recess 15a of the support wall 15 is semicircular. The holder case 1 shown in the figure stores battery modules 2 in two upper and lower stages. Accordingly, the support wall 15 includes an intermediate support wall 15A disposed between the two-stage battery modules 2, and an upper support wall disposed between the top plate 1A of the holder case 1 and the battery module 2 (see FIG. And a lower support wall 15B disposed between the bottom plate 1B and the battery module 2. The upper battery module 2 is sandwiched between the upper support wall and the intermediate support wall 15A, and the lower battery module 2 is sandwiched between the intermediate support wall 15A and the lower support wall 15B, and air for cooling the battery module 2 is blown. The air blowing path 10 to be divided is divided into three regions of a central blowing path 10A and both side blowing paths 10B on both sides of the central blowing path 10A. The air blown to the central air passage 10 </ b> A cools the central portion of the battery module 2. The air blown to the both-side air passage 10B cools both end portions of the battery module 2.

  The holder case 1 blows a larger amount of air to the central part of the battery module 2 than the whole blowing position compared to the whole blowing position, or to the central part of the battery module 2, or only to the central part. A switching mechanism 6 for switching to a central blowing position for blowing air is provided. The illustrated switching mechanism 6 is a flap 7 disposed in the duct 5 of the holder case 1. In the illustrated power supply apparatus, a flap 7 is provided in a suction duct 5A, which is a duct 5 on the inflow side. The flap 7 has a plate 7B fixed to a rotating shaft 7A, and connects the rotating shaft 7A to an actuator (not shown). In the illustrated power supply apparatus, a pair of flaps 7 are disposed in a duct 5. The pair of flaps 7 are driven by the actuator to switch the plate 7B between the entire blowing position and the central blowing position as shown in FIGS. As shown in FIGS. 3 and 4, the air blown from the fan 3 in the state where the flap 7 is switched to the whole blowing position is arranged so that the central air passage 10 </ b> A and both sides are cooled so that the whole battery module 2 is uniformly cooled. The air is sent to both the air passage 10B. As shown in FIGS. 5 and 6, in a state where the flap 7 is switched to the central blowing position, the air blown from the fan 3 is blown to the central blowing path 10 </ b> A. At this time, all of the air blown from the fan 3 is blown to the central blower passage 10A, or almost entirely blown to the central blower passage 10A, but a part of the air can be blown to the both blower passages 10B.

  In the illustrated holder case 1, the duct 5 connected to the fan 3 has a tapered shape that increases in width from the fan 3 toward the battery module 2, and the rotating shaft 7 </ b> A of the flap 7 is provided at the connecting portion with the fan 3. It is connected so that it can rotate. The flap 7 is moved to a position along the inner surface of the duct 5 in the entire blowing position. When the flap 7 is in this position, the air blown from the fan 3 is blown to the central air passage 10A and the both air passages 10B. When the flap 7 is switched to the central air blowing position, the flap 7 is moved to a position facing the support wall 15. When the flap 7 is switched to this position, the air blown from the fan 3 is blown between the pair of support walls 15, blown to the central blower passage 10A, and is not blown to the both blower passages 10B. However, at this time, a part of the air can be blown to the both-side air blowing paths 10B. However, since the central air blowing position is a mode in which the central portion of the battery module 2 is more effectively connected than the both end portions, the air blown to the both-side air passages 10B is compared with the air blown to the central air passage 10A. Thus, for example, it is set to 1/2 or less, preferably 1/3 or less, and more preferably 1/4 or less.

  The flap 7 is driven by an actuator, and is switched between an overall blowing position and a central blowing position. The actuator is a servo motor controlled by the control circuit 4. However, the actuator can also be any drive mechanism that can switch the flap 7 between the overall blowing position and the central blowing position, for example, a hydraulic motor or cylinder driven by air or hydraulic pressure.

  The control circuit 4 detects the temperature of the battery module 2 and controls the operation of the fan 3. The control circuit 4 also controls the switching mechanism 6. The control circuit 4 includes a temperature sensor 8 that detects the temperature of the battery module 2. Further, the control circuit 4 includes a central temperature sensor 8A that detects the temperature of the central portion of the battery module 2, and an end temperature sensor 8B that detects the temperatures of both end portions.

  Furthermore, the control circuit 4 includes a stop sensor (not shown) that determines whether or not the vehicle is in a running state. The stop sensor detects the running state and the stopped state of the vehicle by turning on and off the ignition switch. This is because the ignition switch is turned on while the vehicle is running, and the ignition switch is turned off when the vehicle is stopped.

The control circuit 4 described above cools the battery module 2 in the following manner when the vehicle is running.
(1) When the temperature detected by the center temperature sensor 8A or the end temperature sensor 8B becomes higher than the set temperature, the control circuit 4 operates the fan 3 to cool the battery module 2. At this time, the control circuit 4 switches the switching mechanism 6 to the entire air blowing position and cools the entire battery module 2.
(2) When the battery module 2 is cooled to the set temperature, this is detected by the central temperature sensor 8A or the end temperature sensor 8B. In this state, the control circuit 4 stops the operation of the fan 3.

Furthermore, in the state where the vehicle is stopped, the control circuit 4 cools the battery module 2 in the following steps as shown in the flowchart of FIG.
[Step of n = 1]
The stop of the vehicle is detected by a stop sensor. The stop sensor detects that the vehicle has stopped by detecting that the ignition switch has been switched from on to off.
[Step of n = 2]
The temperature difference of the battery module 2 is detected by the center temperature sensor 8A and the end temperature sensor 8B, and whether or not the detected temperature of the center temperature sensor 8A is larger than the set temperature difference than the detected temperature of the end temperature sensor 8B. judge. In the figure, the set temperature difference is 3 ° C. This set temperature difference can be set to 1 to 5 ° C.
[Step n = 3-4]
If the temperature difference detected by the center temperature sensor 8A and the end temperature sensor 8B is not larger than the set temperature difference (3 ° C.), the fan 3 is stopped without operating in this step, and the step of n = 4 is performed. Loop through n = 2 steps via timer. This step of n = 2 to 4 is looped until the temperature difference of the battery module 2 becomes equal to or larger than the set temperature difference.
When the battery module 2 stops the vehicle and stops the operation of the fan 3 and time elapses, the temperature of the central portion becomes higher than that of both end portions. Therefore, this step is looped to determine whether or not the temperature difference between the central portion and both end portions is equal to or greater than the set temperature difference.

[Step n = 5]
When the temperature difference between the detected temperature of the central temperature sensor 8A and the detected temperature of the end temperature sensor 8B becomes larger than the set temperature difference, the detected temperature of the central temperature sensor 8A is 5 ° C. or higher than the outside air temperature in this step. Determine if it is high. The control circuit 4 includes an outside air temperature sensor for detecting the outside air temperature. This step determines whether or not the central portion of the battery module 2 can be cooled at the outside air temperature. That is, when the outside air temperature is sufficiently lower than the temperature of the central portion of the battery module 2, and in this embodiment, it is determined that the battery module 2 can be cooled by the outside air when it is lower than 5 ° C. When the outside air temperature is not a temperature at which the battery module 2 can be cooled, the process jumps to a step of n = 3 and the fan 3 is not operated.
[Step n = 6]
When the outside air temperature is lower than the temperature of the central part of the battery module 2 by 5 ° C. or more, the control circuit 4 switches the switching mechanism 6 from the entire blowing position to the central blowing position in this step. That is, the flap 7 is switched to the closed position where the air is not sent to the both-side air passages 10B, and the air supplied from the fan 3 is blown to the central air passage 10A.
[Steps n = 7-8]
After switching the switching mechanism 6 to the central air blowing position, the fan 3 is operated in this step. The fan 3 is used until the temperature detected by the center temperature sensor 8A is 2 ° C. or more lower than the temperature detected by the end temperature sensor 8B, that is, the temperature of the center portion of the battery module 2 is 2 ° C. or more Until it is low. Thus, the fan 3 is operated until the central portion becomes lower than the both end portions because the temperature of the central portion rises more than the both end portions when the operation of the fan 3 is stopped. That is, the temperature difference of the battery module 2 can be reduced after the operation of the fan 3 is stopped by cooling the central portion to a lower temperature than both end portions.

  After stopping the operation of the fan 3, jump to the step of n = 2.

It is a perspective view of the power supply device concerning one Example of this invention. It is a disassembled perspective view of the power supply device concerning one Example of this invention. It is a perspective view which shows the internal structure of the state which switched the switching mechanism to the whole ventilation position. It is a top view which shows the internal structure of the state which switched the switching mechanism to the whole ventilation position. It is a perspective view which shows the internal structure of the state which switched the switching mechanism to the center ventilation position. It is a top view which shows the internal structure of the state which switched the switching mechanism to the center ventilation position. It is a schematic sectional drawing which shows an example which blows air on a holder case. It is a schematic sectional drawing which shows another example which blows air on a holder case. It is a schematic sectional drawing which shows another example which blows air on a holder case. It is a flowchart with which a control circuit cools a battery module in the state which stops a vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Holder case 1A ... Top plate 1B ... Bottom plate 2 ... Battery module 2A ... Electrode terminal 3 ... Fan 4 ... Control circuit 5 ... Duct 5A ... Suction duct 6 ... Switching mechanism 7 ... Flap 7A ... Rotary shaft 7B ... Plate 8 ... Temperature Sensor 8A ... Central temperature sensor 8B ... End temperature sensor 10 ... Air air passage 10A ... Central air passage 10B ... Both air passages 11 ... Inlet passage 12 ... Discharge passage 13 ... Cooling gap 14 ... Support recess 15 ... Support wall 15A ... Intermediate Support wall 15B ... Lower support wall
15a ... Fitting recess

Claims (5)

A battery module (2) in which a plurality of unit cells are connected in a straight line, a holder case (1) for storing the plurality of battery modules (2), and a battery module ( A power supply device for a vehicle comprising a fan (3) for cooling 2) and a control circuit (4) for controlling the operation of the fan (3),
The holder case (1) blows a larger amount of air to the central part of the battery module (2) than the two parts, compared to the whole air blowing position. Or a switching mechanism (6) that switches to a central air blowing position that blows air only to the central part,
The control circuit (4) controls both the operation of the fan (3) and the switching of the switching mechanism (6), and includes a stop sensor for detecting the stop of the vehicle,
The control circuit (4) switches the switching mechanism (6) from the entire blowing position to the central blowing position when the vehicle is stopped, and switches the switching mechanism (6) from the entire blowing position to the central blowing position when the vehicle is stopped. A power supply device for a vehicle that operates 3) and blows air to the central portion of the battery module (2) by the fan (3) to cool the central portion of the battery module (2).   The power supply device for a vehicle according to claim 1, wherein the stop sensor of the control circuit (4) detects the stop of the vehicle by detecting the OFF state of the ignition switch.   While the vehicle is stopped, the control circuit (4) detects the temperature difference between the center and both ends of the battery module (2), and the detected temperature difference is larger than the set temperature difference. 2. The vehicle power supply device according to claim 1, wherein air is blown to a central portion of the battery module (2) to cool the battery module (2) with the switching mechanism (6) as a central air blowing position.   The vehicle according to claim 1 or 3, wherein the control circuit (4) detects that the temperature of the central portion of the battery module (2) is lower than the temperatures of both end portions and stops the operation of the fan (3). Power supply. The power supply device for vehicles according to claim 1, wherein the switching mechanism (6) is a flap (7) disposed in the duct (5) of the holder case (1).

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