Traction battery assembly with thermal device

A traction battery includes a first thermal plate disposed within a case, and cells disposed on the first thermal plate. A bracket arrangement is disposed within the case. The bracket arrangement includes a second thermal plate spaced apart from the first thermal plate, and a leg defining at least a portion of a fluid path connecting flow channels of the first and second thermal plates. An electronic component is disposed on the second thermal plate.

TECHNICAL FIELD

The present disclosure relates to traction battery assemblies for motor vehicles and specifically to traction battery assemblies having thermal devices.

BACKGROUND

Vehicles such as battery-electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs) and full hybrid-electric vehicles (FHEVs) contain a traction battery assembly to act as an energy source for vehicle propulsion. The traction battery includes components and systems to assist in managing vehicle performance and operations. The traction battery also includes high voltage components. Traction batteries may include an air or liquid thermal management system to control the temperature of the battery.

SUMMARY

In one embodiment, a traction battery includes a first thermal plate disposed within a case, and cells disposed on the first thermal plate. A bracket arrangement is disposed within the case. The bracket arrangement includes a second thermal plate spaced apart from the first thermal plate, and a leg defining at least a portion of a fluid path connecting flow channels of the first and second thermal plates. An electronic component is disposed on the second thermal plate.

In another embodiment, a traction battery includes a first thermal plate disposed within a case, cells disposed on the first plate, and a second thermal plate spaced apart from the first plate. The second thermal plate is supported by a bracket that includes a leg between the first and second plates. The leg defines at least a portion of a fluid path connecting flow channels of the first and second thermal plates. An electronic component is disposed against the second thermal plate.

In yet another embodiment, a traction battery includes a case having a thermal plate configured to circulate a fluid. Cells are disposed on the thermal plate. A electronic component is supported by a platform that is spaced apart from the thermal plate. An array of heat pipes are arranged to transfer heat from the electronic component to the thermal plate.

DETAILED DESCRIPTION

FIG. 1depicts a schematic of a typical plug-in hybrid-electric vehicle (PHEV). Certain embodiments of this disclosure may be implemented within the context of non-plug-in hybrids and fully electric vehicles. The vehicle12includes one or more electric machines14mechanically connected to a hybrid transmission16. The electric machines14may be capable of operating as a motor or a generator. In addition, the hybrid transmission16may be mechanically connected to an engine18. The hybrid transmission16may also be mechanically connected to a drive shaft20that is mechanically connected to the wheels22. The electric machines14can provide propulsion and deceleration capability when the engine18is turned on or off. The electric machines14also act as generators providing fuel economy benefits by recovering energy through regenerative braking. The electric machines14reduce pollutant emissions and increase fuel economy by reducing the work load of the engine18.

A traction battery or battery pack24stores energy used by the electric machines14. The traction battery24typically provides a high voltage direct current (DC) output from one or more battery cell arrays, sometimes referred to as battery cell stacks, within the traction battery24. The battery cell arrays include one or more battery cells.

The battery cells, such as a prismatic or pouch cell, include electrochemical cells that convert stored chemical energy to electrical energy. The cells include a housing, a positive electrode (cathode) and a negative electrode (anode). An electrolyte allows ions to move between the anode and cathode during discharge, and then return during recharge. Terminals may allow current to flow out of the cell for use by the vehicle. When positioned in an array with multiple battery cells, the terminals of each battery cell may be aligned with opposing terminals (positive and negative) adjacent to one another and a busbar may assist in facilitating a series connection between the multiple battery cells. The battery cells may also be arranged in parallel such that similar terminals (positive and positive or negative and negative) are adjacent to one another.

Different battery pack configurations are available to address individual vehicle variables including packaging constraints and power requirements. The battery cells may be thermally regulated with a thermal management system. Examples of thermal management systems include air cooling systems, liquid cooling systems and a combination of air and liquid systems.

The traction battery24may be electrically connected to one or more power electronics modules26through one or more contactors (not shown). The one or more contactors isolate the traction battery24from other components when opened and connect the traction battery24to other components when closed. The power electronics module26may be electrically connected to the electric machines14and may provide the ability to bi-directionally transfer electrical energy between the traction battery24and the electric machines14. For example, a typical traction battery24provides a DC voltage while the electric machines14require a three-phase alternating current (AC) voltage to function. The power electronics module26may convert the DC voltage to a three-phase AC voltage as required by the electric machines14. In a regenerative mode, the power electronics module26may convert the three-phase AC voltage from the electric machines14acting as generators to the DC voltage required by the traction battery24. The description herein is equally applicable to a pure electric vehicle. In a pure electric vehicle, the hybrid transmission16may be a gear box connected to an electric machine14and the engine18is not present.

In addition to providing energy for propulsion, the traction battery24may provide energy for other vehicle electrical systems. A typical system may include a DC/DC converter module28that converts the high voltage DC output of the traction battery24to a low voltage DC supply that is compatible with other vehicle loads. Other high-voltage loads, such as compressors and electric heaters, may be connected directly to the high-voltage without the use of a DC/DC converter module28. In a typical vehicle, the low-voltage systems are electrically connected to an auxiliary battery30(e.g., a 12 volt battery). The DC/DC converter may also modify the voltage going to the electric machines14.

A battery electric control module (BECM)33may be in communication with the traction battery24. The BECM33may act as a controller for the traction battery24and may also include an electronic monitoring system that manages temperature and state of charge for each of the battery cells. The traction battery24may have a temperature sensor31such as a thermistor or other temperature gauge. The temperature sensor31may be in communication with the BECM33to provide temperature data regarding the traction battery24.

The vehicle12may be recharged by an external power source36. The external power source36is a connection to an electrical outlet. The external power source36may be electrically connected to electric vehicle supply equipment (EVSE)38. The EVSE38may provide circuitry and controls to regulate and manage the transfer of electrical energy between the power source36and the vehicle12. The external power source36may provide DC or AC electric power to the EVSE38. The EVSE38may have a charge connector40for plugging into a charge port34of the vehicle12. The charge port34may be any type of port configured to transfer power from the EVSE38to the vehicle12. The charge port34may be electrically connected to a charger or on-board power conversion module32. The power conversion module32may condition the power supplied from the EVSE38to provide the proper voltage and current levels to the traction battery24. The power conversion module32may interface with the EVSE38to coordinate the delivery of power to the vehicle12. The EVSE connector40may have pins that mate with corresponding recesses of the charge port34.

The various components discussed may have one or more associated controllers to control and monitor the operation of the components. The controllers may communicate via a serial bus (e.g., Controller Area Network (CAN)) or via dedicated electrical conduits.

FIGS. 2 through 8, and the related discussion, describe examples of the traction battery assembly24. Referring toFIGS. 2 and 3, the traction battery assembly24includes a case52having a tray (shown) and a cover (not shown). A first thermal plate54is disposed along a bottom of the case52. The first thermal plate54is configured to circulate a fluid therein and add or remove heat from the case52. At least one battery array56is disposed on the thermal plate54. The battery array56includes a plurality of battery cells58stacked together and electrically connected in series or parallel. The thermal plate54is in contact with each of the battery cells58and may add or remove heat to the cells depending upon operating conditions. For example, if the cells58are above a threshold temperature, a relatively cold fluid is circulated to the first plate54to cool the battery cells. Alternatively, if the battery cells58are below the threshold temperature, a relatively warm fluid is circulated through the first plate54to add heat to the battery cells. The warm fluid may be provided by an internal combustion engine or an electric heater depending upon the vehicle type. A thermal interface material (TIM) may be disposed between the cells58and the thermal plate54. The TIM may be a pad, a gel or a paste.

The traction battery assembly24also includes a bracket arrangement60having a platform62, legs64and a cooling device66. The platform62may define a planar surface and the legs64may extend perpendicularly from the planar surface. The platform62is elevated above the first thermal plate54via the legs64. The bracket arrangement60may include any number of legs; such as one leg, or four legs as is illustrated. The legs64may be connected directly to the thermal plate54or may be connected to the case52. In some embodiments, one or more of the legs64is connected to the first thermal plate54and one or more of the other legs is connected to the case52. The cooling device66may be attached to the platform62. Alternatively, the cooling device66may be integral with the platform62or may be disposed within the platform62. The cooling device66may be an active cooling device or may be passive cooling device. An example active cooling device is a liquid heat exchanger (e.g. a thermal plate) and an example passive cooling system is a heat pipe assembly.

An electronic component68may be attached to a first side of the cooling device66. The electronic component68may be a BECM. The cooling device66removes excess heat created by the BECM68. Another electronic component70is disposed under the bracket60and within a footprint of the bracket60. The electronic component70may be a bus electrical center (BEC), which is electrically connected with the battery arrays56. The BEC70may be disposed on the first thermal plate54or may be disposed on a portion of the case52. One or both of the thermal devices54,66may remove excess heat produced by the BEC70. In some embodiments, the BEC70is in direct contact with a second side of the cooling device66that is opposite the BECM70.

Referring toFIG. 3, the first thermal plate54includes a top72and a bottom74. The bottom74may be disposed on the case52or may define the bottom of the case52. At least one flow channel or pipe76is disposed within the first thermal plate54and is configured to circulate a fluid therein. The pipe76may be a single pipe that serpentines within the thermal plate54or may be a plurality of pipes in a parallel flow arrangement. The thermal plate54includes an entrance port (not shown) and an exit port80that are connected to a thermal management system. The thermal plate54includes an inlet stub82extending from the top72. The inlet stub82is connected to a portion of the pipe76and defines a port86. The thermal plate54also includes an outlet stub84extending from the top72. The outlet stub84is connected to a portion of the pipe76and defines a port88.

The bracket arrangement60includes an inlet leg90, and outlet leg92and a pair of other legs93connected to the top72of the thermal plate54. The inlet leg90defines an inlet channel94and the outlet leg92defines an outlet channel96. The inlet and outlet channels94,96form at least a portion of fluid path connecting the flow channels of the first and second thermal plates54,66. For example, the second thermal plate66includes a single pipe98connected to the inlet channel94at a first end and connected to the outlet channel96at a second end. Alternatively, the second thermal plate66includes multiple pipes.

The inlet leg90is received on the outlet stub84connecting the port88and the inlet channel94in fluid communication. The outlet leg92is received on the inlet stub82connecting the port86and the outlet channel96in fluid communication. In another embodiment, both the inlet and outlet channels are one of the legs.

The first thermal plate54and the second thermal plate66are in fluid communication with each other via the inlet and outlet legs90,92. During operation, a portion of the fluid circulating within pipe76of the first thermal plate54is diverted into the inlet leg90and flows to the second thermal plate66. The fluid then circulates within the pipe98of the second thermal plate66. The fluid then flows from the second thermal plate66to the first thermal plate58via the outlet leg92. Alternatively, the legs90,92include stubs that are received within ports defined in the thermal plate54to connect the channels94,96to the pipe76.

Referring toFIG. 4, another traction battery assembly110is illustrated. The traction battery assembly110includes at least one array112disposed on a first thermal plate114. The first thermal plate114may extend along an entirety of the case bottom or may only extend along a portion of the bottom. The first thermal plate114may include an outlet stub116and an inlet stub118extending from a surface of the thermal plate114. For example, the stubs116,118may extend from a top of the thermal plate or may extend from a side of the thermal plate. The inlet and outlet stubs116,118are fluid communication with the flow channels of the thermal plate114. The stubs are illustrated in a vertical stack configuration, but the stubs may be arranged side by side in a same horizontal plane.

The battery assembly110further includes a bracket arrangement120having a second thermal plate122and a plurality of legs124. The thermal plate122may be integral with the bracket120or may be a separate component that is attached to a platform of the bracket120. In one embodiment, the thermal plate114and the bracket120are arranged adjacent to one another, rather than on top of one another (as illustrated inFIG. 3). In the illustrated embodiment, the legs124of the bracket120are attached to the case.

One of the legs124is an inlet leg126defining at least a portion of a fluid path142connecting the flow channels of the first and second plates114,122. The fluid path142may include an inlet channel130defined in the inlet leg126and a supply line134connected between the inlet channel130and the outlet stub116. Alternatively, the fluid path142may be a single line directly connected between the first and second thermal plates114,116. The single line may be received with a hole extending through a length of the leg126.

Another of the legs124is an outlet leg128defining at least a portion of a fluid path144connecting the flow channels of the first and second plates114,122. The fluid path144may include an outlet channel132defined in the outlet leg128and a return line136connected between the outlet channel132and the inlet stub118. Alternatively, the fluid path144may be a single line directly connected between the first and second thermal plates114,122. The single line may be received with a hole extending through a length of the leg128. In an alternative embodiment, the return line136connects to the thermal management system and does not connect to the first thermal plate114.

The second thermal plate122may include at least one pipe146connected to the inlet channel130at a first end and connected to the outlet channel132at a second end. A portion of the fluid circulating within the first thermal plate114is diverted to the second thermal plate122via the supply line134. The fluid then circulates within the second thermal plate122and returns to the first thermal plate114via the return line136. An electronic component140, such as a BECM, is disposed on the bracket arrangement120and is thermally regulated by the second thermal plate122. Another electronic component138, such as a BEC, is disposed under the bracket arrangement120.

Referring toFIG. 5, a liquid thermal management system150includes a first thermal plate152and a second thermal plate154. The thermal plates are disposed within the traction battery assembly156. The system150also includes a radiator158, a reservoir160and a pump162interconnected with a plurality of lines and valves. The thermal management system150may be a dedicated system or may be plumbed into an existing engine cooling system. Fluid is supplied to the first thermal plate152via a supply line164. The fluid then circulates within one or more first flow channels of the first thermal plate152and exits the first thermal plate into a return line166connected to the radiator158. A portion of the fluid within the first flow channels is diverted to one or more second flow channels within the second thermal plate154via line168. After circulating through the second flow channels, the fluid returns to the first flow channels via line170.

Referring toFIG. 6, another thermal management system180includes a first thermal plate182and a second thermal plate184disposed within the traction battery assembly186. The system180is similar to system150except fluid from the second thermal plate184does not return to the first thermal plate182. Fluid is supplied to the first thermal plate182via a supply line188. The fluid then circulates within first flow channels of the thermal plate182and exits the thermal plate182into a return line190. A portion of the fluid within the first flow channels is diverted to a second flow channel within the second thermal plate184via line193. After circulating through the second flow channels, the fluid exits into the return line190via line196.

Referring toFIGS. 7 and 8, a traction battery assembly200includes a thermal plate202disposed within a case. The thermal plate202includes pipes203for circulating a fluid medium within the thermal plate202. At least one battery array204is disposed on the thermal plate202for heating or cooling the array. A bracket206is disposed within the case. The bracket includes a platform208spaced apart from the thermal plate202and a plurality of legs210connected to the platform208. The base of the legs210may connect to the thermal plate202or the case or both. A first electronic component220is supported by the platform208. A second electronic component222is disposed under the platform208. A passive cooling device212is disposed within the case for cooling at least the first component220. The passive cooling device212extends between the platform208and the thermal plate202to transfer heat from the component222to the thermal plate202. The passive cooling device212may be disposed on top of the platform208or may be integral with the platform208. The passive cooling device212may include an array of heat pipes214arranged in parallel. Each of the heat pipes214includes a first section224extending across at least a portion of the platform208and a second section226extending across at least a portion of the thermal plate202. An intermediate section connects between the first and second sections224,226. The intermediate section may be exposed (as illustrated) or may be encased in a housing. A first heat spreader216may be connected to the array of heat pipes214at the first section224to facilitate heat transfer between the component220and the heat pipes214. The heat spreader216may be a metallic plate such as copper, aluminum or other thermally conductive material. Alternatively, the heat spreader216may be a pair of plates, or a housing, that sandwich the heat pipes214. The passive cooling device212may be arranged such that the electric component220is in contact with the heat spreader216on a side opposite the heat pipes214. The heat pipes214conduct heat from the first component220and carry it to the thermal plate202for removal from the case.

A second heat spreader218may attached to the heat pipes214at the second section226. The heat spreader218may be a single plate, a double plate, or a housing (as described above) and may be made of copper, aluminum or other thermally conductive material. A first side of the heat spreader218may be attached to the thermal plate202and a second side of the spreader may be attached to the heat pipes214. The heat spreader218helps conduct thermal energy from the heat pipes214to the thermal plate202.

In another embodiment, the intermediate portions of heat pipes214may extend through the bracket206as opposed to being off to the side as illustrated inFIG. 7. The intermediate portions may extend through one or more of the legs similar to the fluid lines described in the active cooling system. The heat spreader218may be disposed between a leg210of the bracket206and the thermal plate202. Alternatively, one or more of the legs210may include a thick or expanded lower end that acts like a heat spreader.

In another embodiment, the intermediate portion of the heat pipes214may be attached to an outside surface of the bracket206. In this configuration, one or more of the legs210provides support and shields the heat pipes214from being hit or damaged.