JP2012079441A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack which can heat a battery module without impeding the cooling of the battery module.SOLUTION: A battery pack 1 having a battery module 2 and a structure for cooling or heating the battery module 2 comprises: a suction port 6 from which a gas flows in; an exhaust port 7 for exhausting the gas; and a heating part 3 provided in the housing of the battery pack 1, the heating part 3 generating heat for heating the battery module 2. When the battery module 2 is cooled, a gas that flows in from the suction port 6 exchanges heat with the battery module 2 to cool the battery module 2, and when the battery module 2 is heated, the heating part 3 generates heat and has simultaneously its position brought closer to the battery module 2 than it is positioned when the battery module 2 is cooled.

Description

  The present invention relates to a battery pack including a plurality of battery modules and having a function of heating or cooling the battery modules.

  2. Description of the Related Art In recent years, electric vehicles (EVs) and hybrid vehicles (Hybrid vehicles) have attracted attention for the realization of a low-carbon society. Such electric vehicles and hybrid vehicles include an electric motor for generating a driving force transmitted to the tire. Energy for operating the electric motor is supplied from the secondary battery.

  Particularly in recent years, in order to achieve both extension of travel distance and space saving of battery module arrangement, secondary batteries (nickel metal hydride rechargeable battery or lithium ion) having high energy density have been used instead of lead batteries conventionally used as battery modules. Rechargeable battery) is used.

  These secondary batteries with high energy density differ greatly in charge / discharge efficiency depending on the temperature during charge / discharge compared to lead batteries. For this reason, it is necessary to control the temperature of the battery module.

  Conventional battery packs that control the temperature of the battery module can be used to cool or heat the battery module by blowing air from one or both sides of the battery module with air and exchanging heat with the battery module. There is (for example, Patent Document 1).

  In addition, there is a battery pack that includes a temperature measurement unit in the vicinity of the battery module, and controls the heating of the battery module by supplying power to the heating unit that is in close contact with the battery module when the temperature of the battery module falls below a predetermined temperature. (For example, patent document 2).

JP 2008-135358 A JP 2004-47133 A

  A conventional battery pack cools or heats a battery module by blowing air from a fan. However, when the battery module is heated by blowing as in the conventional battery pack, it is necessary to generate a considerable amount of heat. Therefore, in order to heat the battery module, a heating unit in close contact with the battery module can be provided as in Patent Document 2. Because of the close contact, the amount of heat generated can be reduced. However, when this is done, there is a problem that heat conduction is hindered when the battery module is cooled due to the presence of the heating section.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a battery pack capable of heating a battery module without preventing cooling of the battery module.

The present invention relates to a battery module and a battery pack having a structure for cooling or heating the battery module, wherein an air inlet into which a gas flows, an exhaust outlet through which the gas is discharged, and a housing of the battery pack A heating unit that emits heat for heating the battery module, and when cooling the battery module, the gas flowing in from the intake port cools the battery module by exchanging heat with the battery module, When heating the battery module, the heating unit generates heat, and the position of the heating unit is closer to the battery module than the position of the heating unit when the battery module is cooled. is there.

  In the battery pack of the present invention, when the battery module is heated, the position of the heating unit is closer to the battery module than the position of the heating unit when the battery module is cooled. Heat can be transferred without having to increase the amount of heat generated since the heating unit is brought close to the heating part while securing the flow path.

  By doing in this way, there exists an effect that a battery module can be heated, without preventing cooling of a battery module.

The figure explaining the structure of the battery pack in Embodiment 1 of this invention Diagram explaining the structure Block diagram Diagram explaining the operation Diagram explaining the structure The figure explaining the structure of the heating part in Embodiment 1 of this invention The figure explaining the structure of the battery pack in Embodiment 2 of this invention Diagram explaining the structure of the seat heater The figure explaining the structure of the battery pack in Embodiment 3 of this invention Diagram explaining the structure Diagram explaining the structure

(Embodiment 1)
Hereinafter, a battery pack according to an embodiment of the present invention will be described with reference to FIGS.

  1 and 2 are diagrams for explaining the structure of a battery pack according to an embodiment of the present invention. FIG. 3 is a block diagram of the battery pack according to the embodiment of the present invention.

  As shown in FIG. 1A, the battery pack 1 has a casing, and includes a battery module 2 that is a secondary battery inside the casing, and the electric power stored in the battery module 2 is supplied to the battery pack 1. It is to be supplied to the outside. In addition, the battery module 2 with which the battery pack 1 is provided may be single or plural. When the battery pack 1 includes a plurality of battery modules 2, a wall for partitioning the battery modules 2 can be provided. The casing of the battery pack 1 in the present embodiment also includes this wall.

  The battery pack 1 further includes a heating unit 3 that heats the battery module 2 and a temperature measurement unit 4 that measures the temperature of the battery module 2. The temperature measuring unit 4 is provided in the vicinity of the battery module 2. The battery pack 1 also includes an intake port 6 for taking in air blown from the blower fan 5 and an exhaust port 7 for discharging this air. The heating unit 3 and the blower fan 5 are controlled by the control unit 8. Hereinafter, each part will be described in detail.

  The battery module 2 is configured by connecting a plurality of battery cells 21 (battery cells 21a to 21d) in series as shown in FIG. These battery cells 21 are all secondary batteries. As the battery cell 21, for example, a nickel metal hydride battery, a lithium ion battery, or a high-capacity capacitor can be used.

  The battery module 2 has brackets that hold both ends thereof fixed to the side surface of the casing of the battery pack 1 so that the battery module 2 does not come off due to vibration or the like. When the battery pack 1 includes a plurality of battery modules 2, the battery modules 2 are connected in series.

  The heating unit 3 is provided in the housing of the battery pack 1 and emits heat for heating the battery module 2. Secondary batteries have a predetermined temperature range for use. When the temperature of the secondary battery constituting the battery module 2 is too lower than a predetermined temperature range (for example, 20 ° C. or less), the charge / discharge efficiency is lowered. Moreover, when the temperature of the battery module 2 is too higher than a predetermined temperature range (for example, 50 ° C. or more), the charge / discharge efficiency is lowered, and the battery characteristics are easily deteriorated.

  For this reason, when the temperature of the battery module 2 falls below the predetermined temperature range, the battery module 2 needs to be heated. When the temperature of the battery module 2 exceeds the predetermined temperature range, the battery module 2 is cooled. There is a need.

  In the present embodiment, when the appropriate temperature of battery module 2 (a predetermined temperature that does not require cooling or heating) is set as target temperature Ttg, the temperature of battery module 2 is higher than temperature upper limit value Tmax by comparison with target temperature Ttg. Next, the battery module 2 is cooled.

  When the temperature of the battery module 2 is smaller than the temperature lower limit value Tmin compared to the target temperature Ttg, the battery module 2 is heated. The controller 8 controls the amount of heat generated by the heating unit 3. The temperature upper limit value Tmax is a positive value, and the temperature lower limit value Tmin is a negative value.

  For example, the target temperature Ttg is about 35 ° C., the temperature lower limit value Tmin is about 20 ° C., and the temperature upper limit value Tmax is a temperature of about 50 ° C.

  The temperature measurement unit 4 is a sensor for measuring the temperature of the battery module 2 and outputting it to the control unit 8. The temperature measuring unit 4 is, for example, a thermistor that uses a resistor whose electrical resistance changes due to a temperature change.

  At least one temperature measuring unit 4 is installed in the battery module 2. The position of the temperature measurement unit 4 is installed at a position where the surface temperature of the battery cell 21 can be measured.

  The blower fan 5 blows air. The air volume of the blower fan 5 is controlled by the control unit 8. The blown air flows into the intake port 6 of the battery pack 1. The inflowing air exchanges heat with the battery module 2 (the heat amount of the battery module 2 is absorbed), thereby cooling the battery module 2. The air after heat exchange is exhausted from the exhaust port 7 of the battery pack 1. Although the blower fan 5 is described as blowing air, the blower fan 5 is not limited to air as long as it can exchange heat with the battery module 2.

  The control unit 8 controls the heating unit 3 and the blower fan 5 based on the temperature of the battery module 2 measured by the temperature measurement unit 4.

The control unit 8 includes a CPU and a ROM / RAM. The CPU executes a program stored in the ROM to perform various operations, output control signals, and the like. The CPU uses the RAM as a work area during execution of the program.

  The control unit 8 controls the heating unit 3 when heating the battery module 2 and controls the blower fan 5 when cooling the battery module 2.

  The processing operation of the battery pack configured as described above will be described with reference to FIGS. FIG. 4 is a diagram for explaining the operation of the battery pack (the operation of the control unit 8) in the first embodiment of the present invention. FIG. 5 illustrates the structure of the battery pack according to Embodiment 1 of the present invention, and FIG. 6 illustrates the structure of the heating unit.

  First, the control part 8 acquires the temperature of the some battery module 2 from the temperature measurement part 4 (S01).

  After S01, the control unit 8 compares the temperature of the battery module 2 acquired in S01 with a predetermined target temperature (Ttg), and calculates a difference. For example, when there are nine battery modules 2, the difference temperatures ΔT1 to ΔT9 are calculated by subtracting the target temperature Ttg from the temperature acquired from the temperature measurement unit 4 corresponding to each battery module 2 (S02).

  After S02, the control unit 8 calculates an average value of the difference temperatures ΔT1 to ΔT9 calculated in S02 (S03). Hereinafter, this average value is referred to as an average temperature difference ΔTave.

  After S03, the control unit 8 compares the average temperature difference ΔTave with the temperature lower limit value Tmin and the temperature lower limit value Tmax (S04).

  As a result of the comparison in S04, when the temperature upper limit value Tmax ≦ the average temperature difference ΔTave, the control unit 8 turns on the blower fan 5 and controls the air volume so as to be constant A / average temperature difference ΔTave (S05). ). This is because the battery module 2 needs to be cooled because the average temperature difference ΔTave is equal to or higher than the temperature upper limit value Tmax.

  For this cooling, the control unit 8 adjusts the air volume of the blower fan 5 in inverse proportion to the average temperature difference ΔTave. This is to reduce the air volume of the blower fan 5 as the average temperature difference ΔTave is smaller (the temperature of the battery module 2 is closer to the target temperature Ttg). Here, the constant A is a constant determined by the battery module 2, and is a value calculated from an experiment or the like according to an actual product or the like.

  As a result of the comparison in S04, when the temperature lower limit value Tmin <average temperature difference ΔTave <temperature upper limit value Tmax, the heating unit 3 and the blower fan 5 are stopped (S06). This is because the average temperature difference of the battery module 2 is between the temperature lower limit value Tmin and the temperature upper limit value Tmax, so that it is not particularly necessary to heat or cool the battery module 2.

  As a result of the comparison in S04, when the average temperature difference ΔTave ≦ the temperature lower limit value Tmin, the control unit 8 turns on the heating unit 3 (S07). This is because the battery module 2 needs to be heated because the average temperature difference ΔTave is equal to or lower than the temperature lower limit value Tmin. At this time, the blower fan 5 is OFF. The controller 8 controls the amount of heat generated by the heating unit 3.

  As shown in FIG. 5, when the battery module 2 is heated, the heating unit 3 generates heat, and the position of the heating unit 3 is closer to the battery module 2 than the position of the heating unit 3 when the battery module 2 is cooled. Try to approach them.

  When FIG. 2 described above is compared with FIG. 5 (broken line portion), the position of the heating unit 3 is close to the battery module 2 in FIG. A structure for this will be described below.

  As shown in FIG. 6A, the heating unit 3 includes a heater unit 34 that generates heat and a power cable 31 for supplying power to the heater unit 34. The heater unit 34 radiates heat toward the battery module 2.

  In addition, two metal plates (metal plate 32 and metal plate 33) having different thermal expansion coefficients are overlapped on the opposite side of the heater module 34 from the battery module 2. The structure in which these two metal plates are combined is a so-called bimetal, and its shape changes with temperature. These metal plates are not limited to two as long as they are a plurality of metal plates having different thermal expansion coefficients.

  The heating unit 3 has a flat plate shape as shown in FIG. 6B when the temperature is high (for example, when the ambient temperature of the heating unit 3 is equal to or higher than the temperature lower limit value Tmin). On the other hand, the shape of the heating unit 3 changes when the temperature is low (for example, when the ambient temperature of the heating unit 3 is equal to or lower than the temperature lower limit value Tmin), and an arch shape as shown in FIG.

  FIG. 6B shows the shape of the heating unit 3 when the battery module 2 is cooled (S05) and when neither the battery module 2 is heated nor cooled (S06). FIG. 6C shows the shape of the heating unit 3 when the battery module 2 is heated (S07).

  When the battery module 2 is heated in S07, the position of the heating unit 3 is close to the battery module 2 (FIG. 6 (c)). Naturally moves away from the battery module 2 (approaching the shape of FIG. 6B).

  In the present embodiment, the heating unit 3 is not mechanically driven but is brought close to the battery module 2 using a member whose shape changes depending on temperature, so that special control and supply of energy such as electric power are not required. Yes.

  Note that the control unit 8 returns the processing to the start after S05, S06, or S07 is completed.

  As described above, in the battery pack according to the embodiment of the present invention, when the battery module is heated, the position of the heating unit is closer to the battery module than the position of the heating unit when the battery module is cooled. Therefore, the heat can be transferred without having to increase the amount of heat generated since the heating unit is brought close to the heating unit while securing the flow path of the blown gas during cooling.

  By doing in this way, there exists an effect that a battery module can be heated, without preventing cooling of a battery module.

  In the present embodiment, the battery module 2 is cooled when the temperature of the battery module 2 becomes higher than the upper temperature limit Tmax by comparison with the target temperature Ttg, and is lower than the lower temperature limit Tmin by more than the target temperature Ttg. In this case, it is described that the battery module 2 is heated. However, the comparison is not made with the target temperature Ttg, but if the temperature of the battery module 2 is equal to or higher than the upper limit temperature (target temperature Ttg + temperature upper limit value Tmax), Control may be performed so as to heat the target temperature Ttg + temperature lower limit value Tmin) or less.

In S07, “when the battery module 2 is heated, the heating unit 3 generates heat, and the position of the heating unit 3 is more relative to the battery module 2 than the position of the heating unit 3 when the battery module 2 is cooled. However, at this time, the heating unit 3 may approach the position where it contacts the battery module 2. By doing in this way, the transfer rate of the calorie | heat amount from the heating part 3 to the battery module 2 can be improved.

  The intake port 6 and the exhaust port 7 can be opened and closed, and the control unit 8 may control the opening and closing. By doing so, when the battery module 2 is heated, the intake port 6 and the amount of heat can be prevented from flowing out from the exhaust port 7.

  In the case where the battery module 2 is heated when the control unit 8 controls the opening and closing of the intake port 6 and the exhaust port 7 (S07), the control unit 8 opens the intake port 6 and the exhaust port 7. The blower fan 5 can be turned on. By doing in this way, there exists an effect that the calorie | heat amount emitted by the heating part 3 can be spread | diffused uniformly.

(Embodiment 2)
Hereinafter, the battery pack according to Embodiment 2 of the present invention will be described with reference to FIGS. 7 and 8.
FIG. 7 is a diagram illustrating the structure of the battery pack according to Embodiment 2 of the present invention, and FIG. 8 is a diagram illustrating the structure of the seat heater. In addition, about what has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected, the description is abbreviate | omitted, and a difference is explained in full detail.

  The difference between the first embodiment and the second embodiment is that in the first embodiment, in step S07, the heating unit 3 is moved to the battery module 2 using a member whose shape changes depending on the temperature without using mechanical drive. Although it was made to approach, in Embodiment 2, it is a point which makes the heating part 3 approach the battery module 2 by mechanical drive.

  As shown to Fig.7 (a), the battery module 2 is arrange | positioned inside the sheet | seat heater 9 (equivalent to a heating part) which has arrange | positioned cylindrically. The seat heater 9 includes a heat generating surface, and the heat generating surface is disposed so that the heat generation is directed to the center. When the battery module 2 is cooled (S05), the state shown in FIG. 7A is taken, and the gas blown by the blower fan 5 passes between the seat heater 9 and the battery module 2.

  As shown in FIG. 8, a heat transfer wire 91 is provided inside the heating surface of the seat heater 9. As the heat transfer wire 91, a PTC (Positive Temperature Coefficient) heat wire or a resistance-type heat wire can be used.

  When a resistance type hot wire is used, a current controller for performing temperature control is required. However, when a PTC heat wire is used, a temperature control device or the like is not required, and it is disposed between the storage battery 92 and the heat transfer wire 91. The switch 93 is simple because it can be controlled only by on / off.

  As shown in FIG. 7B, when the battery module 2 is heated (S07), displacement is performed so as to reduce the cross-sectional area of the cylinder of the heating surface provided in the seat heater 9 (S in FIG. 7 is reduced). Let By doing in this way, the position of the heat generating surface of the seat heater 9 approaches the battery module 2.

  As described above, the battery pack according to Embodiment 2 of the present invention has the effect that the battery module 2 can be heated evenly because the seat heater 9 is cylindrical.

(Embodiment 3)
Hereinafter, the battery pack according to Embodiment 3 of the present invention will be described with reference to FIGS.

  9-11 is a figure explaining the structure of the battery pack in Embodiment 3 of this invention. In addition, about what has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected, the description is abbreviate | omitted, and a difference is explained in full detail.

  The difference between the first embodiment and the third embodiment is that, in the first embodiment, in step S07, the heating unit 3 is transferred to the battery module 2 using a member whose shape changes depending on the temperature without using mechanical drive. Although it was made to approach, in Embodiment 3, it is the point which makes the heating part 3 approach the battery module 2 by the mechanical drive by a motor.

  As shown in FIG. 9, the battery pack 1 further includes a motor 10. The motor 10 includes a protruding portion that protrudes under the control of the control unit 8.

  The battery pack 1 includes a heating unit 11 formed of a heating element that can be curved instead of the bimetallic structure, instead of the heating unit 3. The periphery of the heating unit 11 is fixed. As shown in FIG. 9A, the heating surface of the heating unit 11 is disposed so as to face the battery module 2 side.

  When the battery module 2 is cooled (S05), the state shown in FIG. 9A is taken, and the gas blown by the blower fan 5 passes between the heating unit 11 and the battery module 2.

  When the battery module 2 is heated (S07), as shown in FIG. 9B, the motor 10 disposed on the side of the heating unit 11 opposite to the battery module 2 causes the protruding portion to protrude. This protrusion displaces the heating unit 11 in the direction of the battery module 2. By doing so, the position of the heating surface of the heating unit 11 approaches the battery module 2.

  Note that the heating unit 11 can be displaced in the direction of the battery module 2 by using a piezo element instead of the motor 10.

  Another example in which the heating unit 11 is displaced by the motor 10 will be described with reference to FIG. As shown in FIG. 10A, the periphery of the heating unit 11 is fixed by a fixing unit 12. As shown in FIG. 10A, the heating surface of the heating unit 11 is disposed so as to face the battery module 2 side.

  When cooling the battery module 2 (S05), the state shown in FIG. 10A is taken, and the gas blown by the blower fan 5 passes between the heating unit 11 and the battery module 2.

  When the battery module 2 is heated (S07), as shown in FIG. 10B, the rotational force of the motor 10 is converted into a force for displacing the fixing portion 12 in the direction of the battery module 2 by the cam structure. The fixing part 12 is displaced in the direction of the battery module 2 by this force. By doing in this way, the position of the heating surface of the heating unit 11 approaches the battery module 2.

  Another example in which the heating unit 11 is displaced by the motor 10 will be described with reference to FIG. As shown in FIG. 11A, the periphery of the heating unit 11 is fixed by a plurality of fixing units 13. As shown in FIG. 11A, the heating surface of the heating unit 11 is arranged so as to face the battery module 2 side. The heating unit 11 is composed of a heating element that can be bent.

  When the battery module 2 is cooled (S05), the state shown in FIG. 11A is taken, and the gas blown by the blower fan 5 passes between the heating unit 11 and the battery module 2.

  When the battery module 2 is heated (S07), as shown in FIG. 11B, the rotational force of the motor 10 is displaced in a direction in which the distance between the plurality of fixed portions 13 approaches due to the cam structure. Converted into force. By this force, the distance between the plurality of fixing portions 13 approaches. Accordingly, the heating unit 11 is bent and displaced in the direction of the battery module 2. By doing in this way, the position of the heating surface of the heating unit 11 approaches the battery module 2.

  As described above, in the battery pack according to Embodiment 3 of the present invention, the heating unit 11 is displaced using the driving force of the motor 10, so the distance between the heating unit 11 and the battery module 2 is carefully controlled. There is an effect that it can be performed.

  The present invention is useful as a battery pack having a plurality of battery modules and having a function of heating or cooling the battery modules.

DESCRIPTION OF SYMBOLS 1 Battery pack 2 Battery module 21 Battery cell 3 Heating part 31 Power cable 32 Metal plate 33 Metal plate 34 Heater part 4 Temperature measurement part 5 Blower fan 6 Intake port 7 Exhaust port 8 Control part 9 Seat heater 91 Heating wire 92 Storage battery 93 Switch DESCRIPTION OF SYMBOLS 10 Motor 11 Heating part 12 Fixed part 13 Fixed part 14 Drive rod

Claims (5)

A battery module and a battery pack having a structure for cooling or heating the battery module,
An intake port through which gas flows,
An exhaust port for exhausting this gas;
A heating unit that emits heat for heating the battery module to the casing of the battery pack;
When cooling the battery module, the gas flowing from the intake port cools the battery module by exchanging heat with the battery module,
When heating the battery module, the heating unit generates heat, and the position of the heating unit is closer to the battery module than the position of the heating unit when the battery module is cooled. Battery pack featuring. A temperature measuring unit for measuring the temperature of the battery module in the vicinity of the battery module;
The battery module is cooled when the temperature measured by the temperature measurement unit is equal to or higher than a predetermined temperature, and the battery module is heated when the temperature measured by the temperature measurement unit is equal to or lower than a predetermined temperature. The battery pack according to claim 1. The heating unit includes a bimetal whose shape changes as the temperature rises,
When the battery module is heated, the shape of the bimetal included in the heating unit changes depending on the amount of heat generated by the heating unit, and the position of the heating unit approaches the battery module. Item 6. The battery pack according to Item 1. The heating unit includes a heating surface,
The heating surface provided in the heating unit is arranged in a cylindrical shape so that the heat generation is directed to the center, and the battery module is arranged therein,
When the battery module is heated, the position of the heating unit approaches the battery module by displacing the cross-sectional area of the cylinder of the heat generating surface provided in the heating unit. Item 6. The battery pack according to Item 1. A motor for generating power for displacing the position of the heating unit;
The battery pack according to claim 1, wherein when the battery module is heated, the position of the heating unit is displaced so as to approach the battery module by the power of the motor.