Patent Application
20180269547
This disclosure relates to thermal management assemblies for traction battery cells utilized in vehicles.
Electrified vehicles, such as battery-electric vehicles (BEVs), plug-in hybrid-electric vehicles (PHEVs), mild hybrid-electric vehicles (MHEVs), or full hybrid-electric vehicles (FHEVs) contain an energy storage device, such as a high voltage (HV) battery, to act as a propulsion source for the vehicle. The HV battery may include components and systems to assist in managing vehicle performance and operations. The HV battery may include one or more arrays of battery cells interconnected electrically between battery cell terminals and interconnector busbars. The HV battery and surrounding environment may include a thermal management system to assist in managing temperature of the HV battery components, systems, and individual battery cells.
A vehicle traction battery assembly includes a traction battery cell, a case, and a thermal plate. The case defines a cavity to receive the traction battery cell and has a first side defining a first form feature. The thermal plate is for positioning adjacent the traction battery cell and defines a coolant channel sized for engagement with the case via the first form feature such that traction battery cell is in thermal communication with coolant flowing through the coolant channel. The first form feature may be serpentine-shaped or S-shaped. The first form feature may be castle-shaped from a cross-sectional plan view. The case may be multi-layered and include a first polymer layer, a second polymer layer, and an aluminum layer disposed between the polymer layers. The traction battery cell may further include a cell electrode structure retained by the second polymer layer. The first form feature may define spacing for the coolant channel to extend within an area defined by the cell electrode structure to enhance thermal communication therewith. The case may further have a second side defining a second form feature sized for engagement with another coolant channel of another thermal plate. The thermal plate may further define a coolant channel inlet and a coolant channel outlet. The coolant channel inlet and the coolant channel outlet may each be disposed on a same side of the thermal plate.
A vehicle traction battery assembly includes a traction battery, a case, and first and second spacers. The case defines a cavity sized to receive the traction battery cell and defines a form feature on each of opposing faces of the case. The first and second spacers are disposed on either side of the case and each defines a coolant channel sized to facilitate engagement with one of the form features. The traction battery cell may include a cell electrode structure. The form feature may further be defined such that one of the coolant channels extends within an area defined by the cell electrode structure. The case may include an aluminum layer disposed between two polymer layers to structurally reinforce the overall assembly. The coolant channel may define a first castle shape from a cross-sectional plan view and the form feature may be defined to form a second castle shape from a cross-sectional plan view offset from the first castle shape to facilitate thermal communication between coolant flowing through the coolant channel and the traction battery cell. The traction battery cell may be one of a pouch battery cell and a prismatic battery cell. Each of the coolant channels may include an inlet and outlet disposed on a same side of the respective spacer. The traction battery cell may include a cell electrode structure having layers to define a third form feature and a fourth form feature. The form features of the case may be formed by hard pressing a case first side and a case second side upon the cell electrode structure such that the form features of the case are defined by the third form feature and the fourth form feature.
A vehicle traction battery assembly includes battery cell assemblies and a plurality of thermal plates. Each of the battery cell assemblies includes a battery cell disposed within a housing,. Each of the housings defines a first form feature on a first side and a second form feature on a second side. Each of the plurality of thermal plates is disposed between two of the battery cell assemblies and defines a coolant channel for engagement with the first form feature and the second form feature such that coolant flowing through the coolant channel is in thermal communication with the respective battery cell. The battery cell may include a cell electrode structure having layers to define a third form feature and a fourth form feature. The first form feature and the second form feature may be formed by hard pressing the first side and the second side upon the cell electrode structure such that the first form feature and the second form feature are defined by the third form feature and the fourth form feature. The coolant channel may define one or more routers to direct coolant flow between a first direction and a second direction. Each of the housings may include a first polymer layer, a second polymer layer, and an aluminum layer disposed therebetween. The coolant channel may define a first castle shape from a cross-sectional plan view. Each of the first form feature and the second form feature may define a second castle shape from a cross-sectional plan view. The first castle shape portion of the coolant channel and the second castle shape portion of the form features may be offset from one another such that the thermal plate and the housings engage with one another to enhance heat transfer between coolant flowing through the coolant channel and the battery cell. Each of the thermal plates may further define a coolant channel inlet and a coolant channel outlet disposed on a same side of the thermal plate.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ embodiments of the present disclosure. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
A traction battery or battery pack 24 stores energy that can be used by the electric machines 14. The traction battery 24 typically provides a high voltage DC output from one or more battery cell arrays, sometimes referred to as battery cell stacks, within the traction battery 24. The battery cell arrays may include one or more battery cells. The traction battery 24 is electrically connected to one or more power electronics modules 26 through one or more contactors (not shown). The one or more contactors isolate the traction battery 24 from other components when opened and connects the traction battery 24 to other components when closed. The power electronics module 26 is also electrically connected to the electric machines 14 and provides the ability to bi-directionally transfer electrical energy between the traction battery 24 and the electric machines 14. For example, a typical traction battery 24 may provide a DC voltage while the electric machines 14 may require a three-phase AC voltage to function. The power electronics module 26 may convert the DC voltage to a three-phase AC voltage as required by the electric machines 14. In a regenerative mode, the power electronics module 26 may convert the three-phase AC voltage from the electric machines 14 acting as generators to the DC voltage required by the traction battery 24. The description herein is equally applicable to a pure electric vehicle. For a pure electric vehicle, the hybrid transmission 16 may be a gear box connected to an electric machine 14 and the engine 18 may not be present.
In addition to providing energy for propulsion, the traction battery 24 may provide energy for other vehicle electrical systems. A typical system may include a DC/DC converter module 28 that converts the high voltage DC output of the traction battery 24 to 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 module 28. In a typical vehicle, the low-voltage systems are electrically connected to an auxiliary battery 30 (e.g., 12V battery).
A battery electrical control module (BECM) 33 may be in communication with the traction battery 24. The BECM 33 may act as a controller for the traction battery 24 and may also include an electronic monitoring system that manages temperature and charge state of each battery cell of the traction battery 24. The traction battery 24 may have a temperature sensor 31 such as a thermistor or other temperature gauge. The temperature sensor 31 may be in communication with the BECM 33 to provide temperature data regarding the traction battery 24.
The vehicle 12 may be recharged by an external power source 36. The external power source 36 may be an electrical outlet. The external power source 36 may be electrically connected to an electric vehicle supply equipment (EVSE) 38. The EVSE 38 may provide circuitry and controls to regulate and manage the transfer of electrical energy between the power source 36 and the vehicle 12. The external power source 36 may provide DC or AC electric power to the EVSE 38. The EVSE 38 may have a charge connector 40 for plugging into a charge port 34 of the vehicle 12. The charge port 34 may be any type of port configured to transfer power from the EVSE 38 to the vehicle 12. The charge port 34 may be electrically connected to a charger or on-board power conversion module 32. The power conversion module 32 may condition the power supplied from the EVSE 38 to provide the proper voltage and current levels to the traction battery 24. The power conversion module 32 may interface with the EVSE 38 to coordinate the delivery of power to the vehicle 12. The EVSE connector 40 may have pins that mate with corresponding recesses of the charge port 34.
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 discrete conductors.
The battery cells of the traction battery 24, such as a prismatic or pouch-type cell, may include electrochemical elements that convert stored chemical energy to electrical energy. Prismatic cells or pouch-type cells may include a housing, a positive electrode (cathode) and a negative electrode (anode). An electrolyte may allow ions to move between the anode and cathode during discharge, and then return during recharge. Terminals may allow current to flow out of the battery 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. For example, two battery cells may be arranged with positive terminals adjacent to one another, and the next two cells may be arranged with negative terminals adjacent to one another. In this example, the busbar may contact terminals of all four cells.
Contact of the mating surfaces between a thermal plate and surfaces of battery cells is a factor which may affect heat transfer within a battery thermal management system and particularly with regard to conduction between the thermal plate and the battery cells. The mating surfaces may be uneven due to surface tolerances, and/or component irregularities which may result in gaps therebetween.
For example, the first thermal plate 110 may define a coolant channel 130. The coolant channel 130 may have an inlet 111 to receive coolant and an outlet 113 for exiting coolant to flow through. The inlet 111 and the outlet 113 may be located on a same side of the first thermal plate 110. The coolant channel 130 may be shaped in various configurations to enhance heat transfer but not prevent coolant flow such as a fractal configuration or branching. In
The coolant channel 130 may include a plurality of routers to assist in directing coolant flow from a first direction to a second direction. For example, the coolant channel 130 may include one or more routers 134 to assist in transitioning coolant flow between a first direction (represented by arrow 136) and a second direction (represented by arrow 138).
While various embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the disclosure that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to marketability, appearance, consistency, robustness, customer acceptability, reliability, accuracy, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and can be desirable for particular applications.
