WO2011150085A1

WO2011150085A1 - System and method for battery temperature control using cabin air

Info

Publication number: WO2011150085A1
Application number: PCT/US2011/037942
Authority: WO
Inventors: J. Axel Radermacher
Original assignee: Fisker Automotive, Inc.
Priority date: 2010-05-25
Filing date: 2011-05-25
Publication date: 2011-12-01

Abstract

A battery temperature control system includes a case having an inlet and an outlet. The inlet is operable to open and close to allow fluid to enter the case and circulate through to the outlet. A battery cell is disposed in the case and a channel is defined in the case from the inlet to the outlet. The channel forms around the battery cell to allow the fluid entering the inlet to circulate over and around the battery cell. A vent is defined at the outlet of the case to allow for releasing fluid from the case. A fluid delivery source is coupled to the inlet operable to deliver cooling or heating fluid into the channel to contact and circulate around the battery cell. A circulation fan is mounted in the channel operable to circulate fluid through the channel, within the case.

Description

SYSTEM AND METHOD FOR BATTERY TEMPERATURE CONTROL

USING CABIN AIR

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 61/348,017, filed May 25, 2010, which is incorporated herein by reference.

BACKGROUND

[0002] The present disclosure relates generally to hybrid or electric vehicles, and particularly to a battery for a hybrid or electric powered vehicle and controlling the temperature thereof.

DESCRIPTION OF THE RELATED ART

[0003] Vehicles, such as motor vehicles, utilize an energy source in order to provide power to operate the vehicle. While petroleum based products, such as gasoline, dominate as an energy source in traditional combustion engines, alternative energy sources are available, such as methanol, ethanol, natural gas, hydrogen, electricity, solar or the like. A hybrid powered vehicle, referred to as a "hybrid vehicle," utilizes a combination of energy sources in order to power the vehicle. For example, a battery maybe utilized in combination with the traditional combustion engine to provide power to operate the vehicle. Such vehicles are desirable since they take advantage of the benefits of multiple fuel sources in order to enhance performance and range characteristics of the hybrid vehicle relative to a comparable gasoline powered vehicle. [0004] An example of a hybrid vehicle is a vehicle that utilizes a combination of stored electric energy and an internal combustion engine as power sources to propel the vehicle. An electric vehicle is environmentally advantageous due to its low emissions characteristics and the general availability of electricity as a power source. An energy storage device, such as a battery may be quite large, depending on the energy requirements of the vehicle, and will generate heat that is dissipated using various techniques. Typically coolant, such as a liquid or a gas, is used as a medium for transferring heat from the battery. Current cooling systems often use conditioned cabin air to cool the battery. This often requires large amounts of cabin air, and thus increases the time it takes to cool the cabin. Such a delay may cause passenger discomfort. Accordingly, there is a need in the art for an electric or hybrid electric powered vehicle with an improved temperature control, particularly a cooling system and method for achieving desirable battery temperature control.

SUMMARY

[0005] Accordingly, the present disclosure relates to a battery temperature control system that includes a case having an inlet and an outlet The inlet is operable to open and close to allow fluid to enter the case and circulate through to the outlet. A battery cell is disposed in the case and a channel is defined in the case from the inlet to the outlet. The channel forms around the battery cell to allow the fluid entering the inlet to circulate over and around the battery cell. A vent is defined at the outlet of the case to allow for releasing fluid from the case. A fluid delivery source is coupled to the inlet operable to deliver cooling or heating fluid into the channel to contact and circulate around the battery cell. A circulation fan is mounted in the channel operable to circulate fluid through the channel within the case. The inlet and outlet are closed when the fluid is circulated around the battery cell and opened when the fluid has surpassed a predetermined thermal threshold to be removed from the case and allow for fresh fluid to be introduced.

[0006] An advantage of the present disclosure is that a temperature control system for a battery is provided that integrates cooling using cabin air. Another advantage of the present disclosure is that the cooling system reduces the need for complicated fluid distribution arrangements to manage battery temperature. Yet another advantage of the present disclosure is that the integrated system provides direct conductive heat transfer. A further advantage of the present disclosure is that heat transferred from the battery can be redistributed to other areas of the vehicle.

[0007] Other features and advantages of the present disclosure will be readily appreciated, as the same becomes better understood after reading the subsequent description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of a hybrid vehicle, according to an exemplary embodiment.

[0009] FIG. 2 is a view of a hybrid vehicle showing a battery system, according to an exemplary embodiment.

[0010] FIG. 3 illustrates an example battery case having a plurality of battery cells. [0011] FIG. 4 illustrates a plurality of battery cells with open inlet flap and open outlet vent of the battery case.

[0012] FIG. 5 illustrates a plurality of battery cells with closed inlet flap and closed outlet vent of the battery case with air being circulated around the battery cells.

[0013] FIG. 6 illustrates the battery cells of FIG. 5 with the circulating air having absorbed heat from the battery cells and prior to venting.

[0014] FIG. 7 is a flowchart illustrating a method of regulating an internal temperature of a battery for an electric vehicle, according to an exemplary embodiment.

DESCRIPTION

[0015] Referring to the FIGS. 1-2, a vehicle 10 is illustrated. In this example, vehicle 10 includes a solar panel 14. Vehicle 10 can be a plug-in hybrid vehicle that is solar and electric powered. The vehicle 10 includes a body structure having a frame and outer panels 12 covering the frame that cooperatively form the shape of the vehicle. The vehicle 10 includes an interior space 11 referred to as a passenger compartment. For a convertible style vehicle 10, the passenger compartment 11 may be enclosed by a moveable convertible top that covers the passenger compartment 11 in an extended position. The vehicle 10 can also include a storage space 13 referred to as a trunk or luggage compartment 13. The trunk or luggage compartment 13 is typically accessible via a deck lid 15. The deck lid 15 can be a panel member pivotally connected to the vehicle body, such that the deck lid 15 can articulate in multiple positions. For example, the deck lid 15 may pivot about a forward edge 15A in order to provide access to the trunk 13 of the vehicle 10. In a particular example, the deck lid 15 may pivot about a rearward edge 15B in order to stow the folded top within the vehicle trunk 13. A front or engine compartment 16 typically extends forwardly from the passenger compartment 11 and is covered from above by a hood 19. The hood can be pivotally mounted at a proximal end 19A of the front compartment 16 adjacent the passenger compartment 11 to allow access to mechanical and electrical components mounted in the front compartment 16. A power source, such as an engine, typically engages a drive shaft (not shown) and in combination with the wheels W define a drive train (also referred to as a power train), commonly referred to as a group of components that generate power and deliver it to the road surface. In certain embodiments, the engine may be located in or below the rear compartment 13.

[0016] In an example, the power train is a plug-in hybrid, and includes an electrically powered motor and motor controller (not shown). Vehicle 10 may also include a gasoline powered engine that supplements the electric motor when required under certain operating conditions. The electrical energy can be stored in an energy storage device, such as a battery system 18. Various types of batteries are available, such as lead acid, or lithium-ion or the like. It should be appreciated that the vehicle may include more than one type of battery or energy storage system 18. Generally, the battery supplies power in the form of electricity to operate various vehicle components. In this example, there is a low voltage battery (not shown) that provides electrical power to vehicle components (i.e., a typical 12 V lead acid battery) and a high voltage battery 18 (i.e., 9 400 V traction battery) that provides electrical power to an electric drive motor. The battery may be in communication with a control system that regulates the distribution of power within vehicle 10, such as to the electric drive motor, a vehicle component, other accessories, or the like. In an example, the high voltage battery 18 receives electrical energy from any of a plug-in source, the low voltage battery, solar panel 14, or combinations thereof.

[0017] The battery 18 may be a single unit, or a plurality of modules or individual battery cells 32 arranged in a predetermined manner, such as in a series. Each battery cell 32 is operable to store electrical energy and deliver that energy upon demand. In an example, an electrochemical battery cell consists of two half-cells. Each half-cell consists of an electrode, and an electrolyte. The two half-cells may use the same electrolyte, or they may use different electrolytes. Chemical reactions in the cell may involve the electrolyte, the electrodes or an external substance (as in fuel cells which may use hydrogen gas as a reactant). In a full electrochemical cell, species from one half-cell lose electrons (oxidation) to their electrode while species from the other half-cell gain electrons (reduction) from their electrode. A salt bridge (i.e. filter paper soaked in KNO₃) is often employed to provide ionic contact between two half-cells with different electrolytes— to prevent the solutions from mixing and causing unwanted side reactions. As electrons flow from one half-cell to the other, a difference in charge is established. Other devices for achieving separation of solutions are porous pots and gelled solutions.

[0018] Various types of batteries are available, such as lead acid, or lithium-ion or the like. The battery 18 is contained within a battery case 20. Various strategies are available to cool the battery, such as the circulation of conditioned air or a fluid in or around the battery case 20. Vehicle 10 may include more than one type of battery or energy storage device. Case 20 can be constructed of any suitable material. Non-conductive portions (not shown) can be included to cover exposed electrically active portions of the individual cells 32. In an example, a module controller (not shown) is provided and coupled to the individual cells 32 to monitor individual voltage of each of the cells 32. The controller can further be configured to balance the cells 32 to achieve desired voltage distribution. For example, if one particular battery cell is delivering higher voltage than desired, the controller can instruct that cell to bleed some voltage and redistribute the voltage to a cell that is running lower voltage than desired. Moreover, the module controller can communicate the voltage measurements to a full system controller (not shown).

[0019] The battery 18 is supported within the vehicle by a battery tray 22. In this example, the battery 18 and battery tray 22 extend longitudinally along the length of the vehicle. In a further example, no tray is used and the battery 18 is suspended by a device or holding means for holding the battery 18 in place. The battery tray 22 can be fabricated from a metal material, such as aluminum or the like. The battery tray 22 can be secured to the vehicle frame using a fastener, such as a bolt. A seal is applied between a flange portion of the base member and the vehicle frame to prevent the intrusion of elements such as moisture, dirt, or the like into the interior of the battery 18. An example of a sealant is rubber, foam, adhesive, or the like.

[0020] Referring to FIGS. 3-5, a thermal management system 30 is illustrated operable to adjust thermal conditions of an example battery 18. In this example, the battery 18 includes a plurality of battery cells 32 arranged in a stack. In a further example, battery 18 includes about 10 to 50 individual battery cells 32. Typically, battery cells 32 are arranged or stacked together either in a vertical or horizontal stack as a series of cells 32. Battery cells 32 typically define a substantially rectangular geometry having a relatively thin side profile relative to the substantially larger flat surface. Battery cells 32 can be referred to as a "pouch cell" and this geometry can be referred to as a "notebook" configuration. In a vertical stack of the battery cells 32, each individual cell lies substantially horizontal and flat and the cells 32 can be stacked on top of each other. In a further example, cells 32 can be aligned vertically and stacked against each other in a horizontal stack, similar to books in a book case.

[0021] Formed around and between the stacks are fluid channels 34 defined to allow fluid to flow between the surfaces of the individual cells 32. A single channel can be formed or a plurality of channels. In an example, the fluid is air and in a further example, the fluid is cabin air captured from the interior space 11 of vehicle 10. Fluid contacting the battery cells 32 allows for heat transfer, either heating or cooling depending on the desired thermal treatment of the battery 18 and the individual cells 32. An inlet 36 into the battery case 20 is provided that allows air to enter the isolated space of the battery cells 32 and flow through the fluid channels 34. The inlet 36 is typically an opening formed at one end of a conduit 38 connected to a heating ventilation and air conditioning system of the vehicle (HVAC) 40. In a further example, a plurality of inlets are provided to allow for multiple fluid ports into the case 10. Inlet 36 is operable to open and close to allow or prevent fluid from entering case 20. The HVAC system 40 provides either cooling or heating air through the vehicle depending on a desired result.

[0022] Thermal system 30 can include a mechanical flow blockage at the inlet 36. In this example, the flow blockage is a flap or door 42. In a further example, a flow valve or solenoid can be disposed in inlet 32 to prevent or allow flow into the case. Flap 42 is operable to open and close. When flap 42 is open, then fluid delivered from HVAC 40 can enter conduit 38 and into casing 20 to contact the battery cells 32. When flap 42 is closed, then the fluid in the pack 20 flowing through the channels 34 continuously flows around the battery cells 32. In an example, operation of flap 42 is controlled by a vehicle (or battery) controller and physically opens or closes according to an instruction from the controller. The controller can be in communication with a thermocouple or similar device that measures the internal temperature within the casing 20. The controller can respond to open or close flap 42 based on predetermined or preset temperature thresholds. The controllers can be incorporated into a vehicle controller that controls various vehicle operations and mounted in the vehicle. The controller can include a memory and a processor.

[0023] In an example, system 30 includes at least a circulation fan 46 positioned in the channels 34. The fan 46 can be operationally in communication with the controller to be turned on and off. When turned on, fan 46 is operable to circulate fluid through channels 34. This will facilitate direct fluid contact with the surface of the individual battery cells 32. Another fan 46 can be positioned in conduit 38. The fan 46 in conduit 38 can be turned on by the controller to deliver fluid from the HVAC 40 through the conduit 38 and inlet 36 to enter casing 20.

[0024] In an example, at least a vent 44 can be provided as an outlet to open and close for venting case 20 to release the fluid. In a further example, a plurality of vents 44 are provided. As air circulates through case 20 and over battery cells 32 it can get warmer or cooler and once reaching an undesired thermal threshold should be vented out of case 20 and optionally replaced by new air to manage the thermal properties of the cells 32. In this example, vent 44 is provided on case 20 at an opposite side from inlet 36. Accordingly, in such a configuration, the vent 44 can be opened to release air while inlet 36 is opened to allow air to enter case 20. In another example, the controller monitors the battery cell 32 temperature and controls vent 44 to open to purge or release air out of case 20 while new air enters case 20 through inlet 36. The relative position of the inlet 36 from the vent 44 can be a suitable distance to allow efficient circulation of new air while purging the warmer air. In an example, vent 44 is positioned on an upper surface of the case 20 to allow warm air to exit and positioned relatively opposite the side of the inlet 36.

[0025] In an example of FIG. 4, system 30 includes flap 42 open to allow cold air 48 to enter case 20 through opening 36. In this example, it is desired to cool the battery cells 32 and reduce their operating temperature. Accordingly, cold air 48 is introduced into case 20. The cold air 48 can be from any cooling system including cabin air or ambient air. Flap 42 remains open a sufficient amount of time to allow fans 46 to introduce an amount of air sufficient to cool the battery cells 32 to a desired temperature. Flap 42 is then closed to allow the air 48 introduced into case 20 to circulate over the battery cells 32. By keeping flap 42 closed during cooling, the HVAC 40 can function more efficiently because excess cooling air is not being used to cool the battery. The air from the HVAC 40 is being circulated through the vehicle rather than into case 20. Heat transfers from the battery cells 32 to the circulating cold air causing the air temperature to rise. Once the temperature of the air reaches a certain threshold, vent 44 can be opened to allow release of the hot air 50. With the warmer air purging, new colder air 48 can be introduced back into the case.

[0026] FIG. 5 illustrates an example with both flaps 42 and 44 are closed allowing for cold air 48 to circulate through channels 34 and contact the battery cells 32. As cold air 48 circulates through channels 34, it absorbs heat from the battery cells 32 and becomes warm air 52. As shown in FIG. 6, as warm air 52 continues to absorb heat from battery cells 32, it becomes hot air 50. Once the air is hot, new cold air needs to be introduced into the case 20. A temperature sensor (not shown) can be mounted inside case 40 and coupled to the controller. Once the air becomes hot, the controller can open the flap 42 and vent 44 to release hot air and introduce cold air. In a further example, hot air can be introduced to warm the battery and when the air is cooled, it can be purged through vent 44 to allow for new hot air to be introduced.

[0027] When air is heated, the vehicles air conditioning (AC) can be used to remove moisture from the air before being introduced to the battery cells. The fans can be used to control fresh air flow to the battery cells. The vent or vents can be controlled to regulate air flow into and out of the battery case. The fans can be used in conjunction with the vent or vents to control air flow around the battery cells. The vents also can form a seal with the case to prevent contamination of battery cells. In another example, cool air can be pulled from other sources other than the HVAC system of the vehicle. For example, a dedicated cooling source such as an AC evaporator can be provided that introduces cooling fluid into the battery case. In an even further example, a dedicated heater can be used. In a battery cooling example, the heat rejected from the battery cells can be redistributed to other vehicle systems requiring heat. In yet another example, a thermal plate can be provided in contact with and in between the individual battery cells. The plates can be fabricated from aluminum and made operable to absorb the thermal fluid to either cool or heat the individual battery cells.

[0028] Thermal system 30 can be incorporated into any hybrid vehicle 10 that is fully or partially electric powered. System 30 can be mounted in various exemplary locations of the vehicle 10. In an example, system 30 is mounted in the front or engine compartment 16. In a further example, system 30 is mounted underneath the passenger compartment 11. In an even further example, system 30 is mounted underneath the rear compartment 13. In still an even further example, system 30 extends between at least two of the front compartment 16, beneath or through the passenger compartment 11 , and the rear compartment 13. [0029] The hybrid vehicle 10 may also include other features conventionally known for a vehicle, such as a gasoline engine, other controllers, a drive train or the like.

[0030] Referring now to FIG. 7, a flowchart illustrating a method of regulating an internal temperature of a battery for an electric vehicle according to an exemplary embodiment is shown. In operation, the method begins at block 100 and includes the step of monitoring the internal temperature of the battery using a controller in operative communication with a sensor that measures the internal temperature of the battery. The method proceeds to block 110 which includes the step of circulating a fluid through the battery when a first predetermined thermal threshold is reached, wherein the fluid is air from an interior cabin space of the vehicle. The method then proceeds to block 120 which includes the step of controlling an inlet opening and an outlet opening to vary the circulation of air. Next, the method proceeds to block 130 which includes the step of controlling fluid circulation until a second predetermined thermal threshold is reached to close the inlet opening and outlet opening.

[0031] Many modifications and variations of the present disclosure are possible in light of the above teachings. Therefore, within the scope of the appended claim, the present disclosure may be practiced other than as specifically described.

Claims

WHAT IS CLAIMED IS: 1. A battery temperature control system for an electric vehicle comprising:

a case having an inlet and an outlet, wherein the inlet is operable to open and close to enable a fluid for heating or cooling to enter the case and circulate through to the outlet;

a battery cell disposed in the case;

a channel defined in the case from the inlet to the outlet, wherein the channel forms around the battery cell to allow the fluid entering the inlet to circulate over and around the battery cell;

a vent at the outlet of the case to enable fluid to be released from the case; and

a fluid delivery source coupled to the inlet operable to deliver the fluid into the channel to contact and circulate around the battery cell, wherein the inlet and outlet are closed when the fluid is circulated around the battery cell and opened when the fluid has surpassed a predetermined thermal threshold to be removed from the case and allow for fresh fluid to be introduced.

2. The battery temperature control system of Claim 1, wherein the fluid is air captured from an interior cabin space of the vehicle.

3. The battery temperature control system of Claim 1, wherein the inlet is connected to a heating ventilation and air conditioning system of the vehicle that provides air for circulation into the battery temperature control system to thereby heat or cool the battery cell.

4. The battery temperature control system of Claim 1, further comprising a valve disposed within the inlet wherein the valve is operative!y connected to a controller that opens and closes the valve to heat or cool the battery as needed.

5. The battery temperature control system of Claim 4, wherein the controller is in operative communication with a thermocouple that measures the internal temperature of the battery such that the controller opens or closes the valve when the predetermined thermal threshold is reached.

6. The battery temperature control system of Claim 5, further comprising a circulation fan mounted in the channel and operable to circulate the fluid through the channel within the case.

7. The battery temperature control system of Claim 1 , further comprising a plurality of battery cells arranged in a stack as a series of cells.

8. The battery temperature control system of Claim 1 , further comprising a plurality of channels formed around and between the stacks.

9. The battery temperature control system of Claim 1 , further comprising a plurality of inlets operatively connected to a plurality of channels that circulate fluid around the battery cell.

10. The battery temperature control system of Claim 1, further comprising a plurality of vents operatively connected to a plurality of channels and wherein the plurality of vents are operatively connected to a controller that monitors the battery cell temperature and controls the plurality of vents to open and purge fluid from the case when a predetermined temperature threshold is reached.

11. The battery temperature control system of Claim 1 , wherein the inlet is connected to an air conditioning evaporator that provides a cooling fluid into the battery case.

12. A battery temperature control system for an electric vehicle comprising:

a battery cell disposed in the case;

a fluid delivery source coupled to the inlet operable to deliver the fluid into the channel to contact and circulate around the battery cell, wherein the inlet and outlet are closed when the fluid is circulated around the battery cell and opened when the fluid has surpassed a predetermined thermal threshold to be removed from the case and allow for fresh fluid to be introduced, and wherein the inlet is connected to a heating ventilation and air conditioning system of the vehicle that provides air for circulation into the battery temperature control system to thereby heat or cool the battery cell.

13. The battery temperature control system of Claim 12, further comprising a valve disposed within the inlet wherein the valve is operatively connected to a controller that opens and closes the valve to heat or cool the battery as needed.

14. The battery temperature control system of Claim 13, wherein the controller is in operative communication with a thermocouple that measures the internal temperature of the battery such that the controller opens or closes the valve when the predetermined thermal threshold is reached.

15. A method of regulating an internal temperature of a battery for an electric vehicle, the method comprising the steps of:

monitoring the internal temperature of the battery using a controller in operative communication with a sensor that measures the internal temperature of the battery;

circulating a fluid through the battery when a first predetermined thermal threshold is reached, wherein the fluid is air from an interior cabin space of the vehicle.

16. The method of Claim 15, wherein the step of circulating a fluid further includes the step of controlling an inlet opening and an outlet opening to vary the circulation of air.

17. The method of Claim 15, further comprising the step of controlling fluid circulation until a second predetermined threshold is reached to close the inlet opening and the outlet opening.