Traction battery arrangement

Abstract

Traction battery arrangement (50) comprising: a first and a second group (54, 56), each having cells (60) with two terminals on a terminal side (72) of the group (54, 56) and arranged such that the terminal sides (72) are opposite each other; and a heat-conducting plate (88) arranged between the groups (54, 56) and in contact with the terminal sides (72) of the group (54, 56), wherein a terminal of a cell (60) in the first group (54) is mechanically and electrically coupled to a terminal of a cell (60) in the second group (56) via a busbar (124), wherein another terminal of the cell (60) in the first group (54) is mechanically and electrically coupled to a terminal of another cell (60) in the second group (56) via another busbar (122).

Description

TECHNICAL FIELDThe present disclosure relates to traction battery assemblies for motor vehicles.BACKGROUNDVehicles, such as battery-powered vehicles and hybrid electric vehicles, include a traction battery assembly that serves as a power source for the vehicle. The traction battery may include components and systems to assist in managing vehicle performance and operation. The traction battery may also include high voltage components and may include an air or liquid thermal management system for regulating the temperature of the battery. Battery arrangements are known, for example, from DE 10 2007 063 195 A1, DE 10 2013 016 100 A1, DE 10 2012 015 910 A1 and DE 10 2011 121 488 A1.SUMMARYAccording to one embodiment, a traction battery assembly includes first and second groups each having cells with two terminals on a terminal side of the group. The groups are arranged such that the terminal sides are opposed to each other. A heat conducting plate is disposed between the groups and in contact with the terminal sides. One bus bar mechanically and electrically connects one terminal of a cell in the first group to one terminal of a cell in the second group, and another terminal of the cell in the first group is mechanically and electrically coupled to one terminal of another cell in the second group via another bus bar.According to another embodiment, a traction battery assembly includes first and second groups, each including cells having terminals on a terminal side of the group. The groups are arranged such that the terminal sides are opposed to each other. A cell of the first group is mechanically and electrically coupled at one terminal to a coplanar cell of the second group via a first bus bar and at another terminal to another cell of the second group adjacent to the coplanar cell via a second bus bar. Each of the first and second groups defines a longitudinal axis and the longitudinal axis of the first group is substantially parallel to the longitudinal axis of the second group. A major axis of the first bus bar is disposed substantially perpendicular to the longitudinal axes of the groups.According to yet another embodiment, a traction battery assembly includes first and second groups each having a plurality of cells with a pair of opposing larger sides. The cells are arranged in a stack such that the larger sides of adjacent cells are opposite each other. Each of the cells has terminals on a terminal side extending between the larger sides. A first cell of the first group and a second cell of the second group are coplanar with respect to each other and arranged such that the terminal sides are opposite each other. The first cell is mechanically and electrically coupled to the second cell by a first bus bar, and is mechanically and electrically coupled to a third cell by a second bus bar. The third cell is in the second group and is adjacent to the second cell. A major axis of the first bus bar is disposed substantially coplanar with the first and second cells.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic illustration of an example hybrid vehicle. FIG. 2 is a fragmentary front view of a traction battery assembly. FIG. 3 is a perspective view illustrating one of the groups, a thermal plate, and bus bars of the traction battery assembly of FIG. 2. FIG. 4 is a fragmentary top plan view of the traction battery assembly of FIG. 2 with the carrier omitted. FIG. 5 is a fragmentary bottom plan view of the traction battery assembly of FIG. 2 with the carrier omitted. FIG. 6 is a fragmentary front view of another traction battery assembly.DETAILED DESCRIPTIONEmbodiments of the present invention are disclosed herein. It is to be understood, however, that the disclosed embodiments are merely examples and that other embodiments may 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 various applications of the present invention. As will be appreciated by those of ordinary skill in the art, various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to provide embodiments that are not explicitly illustrated or described. The combinations of illustrated features 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.FIG. 1 schematically illustrates a typical plug-in hybrid electric vehicle (PHEV). However, certain embodiments may also be implemented in conjunction with vehicles other than plug-in hybrid and electric-only powered vehicles. The vehicle 12 may include one or more electric machines 14 mechanically connected to a hybrid transmission 16. The electric machines 14 may be capable of operating as a motor or as a generator. Additionally, the hybrid transmission 16 may be mechanically connected to an internal combustion engine 18. The hybrid transmission 16 may also be mechanically connected to an input shaft 20 that is mechanically connected to the wheels 22. The electric machines 14 may provide propulsion and deceleration capability when the engine 18 is on or off. The electric machines 14 also function as generators and may provide fuel economy benefits by recovering energy through regenerative braking. The electric machines 14 reduce pollutant emissions and increase fuel economy by reducing the workload of the engine 18.A traction battery or battery pack 24 stores energy that may be used by the electric machines 14. The traction battery 24 typically provides a high voltage direct current (DC) output from one or more battery cell groups in the traction battery 24, sometimes also referred to as battery cell stacks. The battery cell groups may include one or more battery cells, also referred to as cells in the context of this disclosure in the abbreviated notation.The battery cells, such as a prismatic or pouch cell, include electrochemical cells that convert stored chemical energy to electrical energy. The cells may include a case, 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 recharging. Terminals may allow current to flow out of the cell for use by the vehicle. When positioned in a group having multiple battery cells, the terminals of each battery cell may be aligned with opposing terminals (plus and minus) adjacent to each other, and a bus bar may help facilitate series connection between the multiple battery cells. The battery cells can also be arranged in parallel, so that similar connections (plus and plus or minus and minus) are adjacent to one another.Different battery pack configurations may be available to address individual vehicle variables, including packaging constraints and power requirements. The battery cells can be thermally regulated by a thermal management system. Examples of thermal management systems may include air cooled systems, liquid cooled systems, and a combination of air and liquid systems.The traction battery 24 may be electrically connected to one or more power electronics modules 26 through one or more contactors (not shown). The one or more contactors disconnect the traction battery 24 from other components when open and connect the traction battery 24 to other components when closed. The power electronics module 26 may be 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 operate. 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 that function as generators to the DC voltage required by the traction battery 24. The description herein may be equally applied to a purely electric powered vehicle. In a purely electrically powered vehicle, the hybrid transmission 16 may be a transmission connected to an electric machine 14, and the engine 18 may not be present.In addition to the traction battery 24 providing energy for propulsion, it 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 compatible with other vehicle components. Other high voltage loads, such as compressors and electric heating elements, may be directly connected to the high voltage supply 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., a 12 volt battery).A battery electrical control module (BECM) 33 may be in communication with the traction battery 24. The BECM 33 may function as a controller for the traction battery 24, and may also include an electronic monitoring system that manages temperature and state of charge for each of the battery cells. The traction battery 24 may include a temperature sensor 31, such as a thermistor or other temperature sensing instrument. 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 from an external power source 36. The external power source 36 is a connection to an electrical outlet. The external power source 36 may be electrically connected to 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 electrical power to the EVSE 38. The EVSE 38 may include a charge connector 40 to plug 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 charging port 34 may be electrically connected to a charger or an 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 be coupled to 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 include one or more associated controllers to control and monitor the operation of the components. The controllers may be in communication via a serial bus (e.g., controller area network (CAN)) or via dedicated electrical lines.FIGS. 2-6 and the related discussion describe examples of the traction battery assembly 24. with reference to FIGS. 2 and 3, a traction battery assembly 50 includes a carrier 52 and battery groups, also referred to in short term as groups, disposed on the carrier 52 within the scope of this disclosure. For example, a first battery pack 54 and a second battery pack 56 may be juxtaposed on the carrier 52 such that the longitudinal axis (into the side) of each pack is substantially parallel. Each of the groups includes a plurality of battery cells 60. Each cell 60 has larger sides 62 and smaller sides 64. Terminals 68 may extend from one of the smaller sides 64. This side may be referred to as a terminal side 66 of the cell 60. Each cell 60 may have a positive and a negative terminal. Each cell 60 may also include a vent hole 70 disposed on one of the sides. The vent hole 70 may be located on the port side 66 of the cell between the ports 68. The vent bore 70 is configured to discharge gas from the interior chamber of the cell 60 when the pressure within the cell exceeds a threshold.The cells 60 may be stacked in a respective group such that the larger sides 62 of adjacent cells are contiguous. The cells 60 may be arranged in the groups such that all of the terminal sides 66 are on a same side of the group and together define a terminal side 72 of the group. The groups may be secured to the carrier by retaining means 74. The retainers 74 may include end plates 76 and tension members 78. Each of the end plates 76 has a mounting surface 80 for receiving a fastener 82 to secure the end plates 76 to the bracket 52. Alternatively, the end plates 76 may be welded or bonded to the bracket 52. The biasing members 78 are connected between the end plates 76 and may apply compressive pressure to the groups 54, 56. The tension members 78 may be connected to the end plates 76 by fasteners, welding, brazing, or adhesive.The first and second battery groups 54, 56 are arranged on the carrier 52 such that the connection side 72 of the first group 54 is opposite the connection side 72 of the second group 56. A thermal plate 88 may be disposed between the first and second battery groups 54, 56 such that at least a portion of the thermal plate 88 contacts the terminal side 66 of each cell 60. The heat conducting plate can be arranged between the connections 68. The thermal plate 88 may be a U-shaped thermal plate having a first leg 90 and a second leg 92. An intermediate connection region 94 may connect the first and second legs 90, 92 in fluid communication with each other. The thermal plate 88 may also include an inlet opening 96 disposed on the first leg 90 and an outlet opening 98 disposed on the second leg 92. The thermal plate 88 is connected via the openings to a thermal management system (not shown) and is configured to circulate coolant through the plate to selectively draw or supply heat to the cells 60 as needed. The first and second legs 90, 92 are spaced apart from each other and define a ventilation duct 100. The cells 60 and the thermal plate 88 may be arranged such that the vent holes 70 are in fluid communication with the vent passage 100. When gas is discharged from the cells via the vent holes 70, the gas is sent through the vent channel into a ventilation system (not shown) to transport the gas to the outside of the passenger compartment.A thermal interface material (TIM) may be deposited between the cells 60 and the thermal plate 88. The TIM may be a thermally conductive adhesive used to secure the thermal plate 88 in place. The heat conducting plate 88 can also be fastened to the clamping elements 78 by fastening elements or welding.The heat conducting plate 88 is not limited to the illustrated U-shaped embodiment. For example, the thermal plate 88 may be rectangular. The thermal plate 88 may also include more than one thermal plate. For example, first and second heat conduction plates are disposed between each of the groups. The pair of heat plates may cooperate to define a vent passage in fluid communication with the vent bores.Referring to FIGS. 3, 4, and 5, the first and second groups 54, 56 may be arranged such that the cells 60 of the groups are aligned in cell pairs. Each cell in the pair may be immediately opposite the other. Each cell pair includes a cell from the first group 54 and a cell from the second group 56. For example, cell 1 and cell 2 form a first cell pair 102, and cell 3 and cell 4 form a second cell pair 104, etc. The cells of each cell pair may be coplanar, as illustrated in FIGS. 4 and 5. For example, cells 1 and 2 both lie in a plane 108. The cells in each cell pair are spaced apart to prevent inadvertent contact of the terminals that would cause a short circuit in the traction battery. Selected terminals 68 are mechanically and electrically coupled via busbars.Each of the cells 60 may have an upper terminal and a lower terminal. For example, cell 1 has an upper terminal 110 and a lower terminal 112. Cell 2 has an upper terminal 114 and a lower terminal 116. Cell 4 has an upper terminal 118 and a lower terminal 120. The bottom terminal 112 of cell 1 may be mechanically and electrically coupled to the bottom terminal 116 of cell 2 via a bus bar 124. The major axis of the bus bar 124 may be substantially coplanar with the cell pair 102. The top terminal 110 of cell 1 may be mechanically and electrically coupled to the top terminal 118 of cell 4 via a bus bar 122. The major axis 131 of the bus bar 122 may be angled 5 to 85 degrees, inclusive, with respect to the longitudinal axis of the groups 54. Thus, each cell is connected to the cell of its pair via a straight bus bar and is connected to a cell of another pair via an angled bus bar. This bus bar arrangement enables the first and second groups 54, 56 to be electrically connected in a single series connection. For example, electricity may flow from cell 1 to cell 4 to cell 3 to cell 6, etc. In some embodiments, the angled bus bar is on the bottom of the group and the straight bus bar is on the top.The heat conducting plate is an optional feature and is not included in all embodiments. FIG. 6 illustrates a traction battery 150 that may not include a thermal plate. The traction battery 150 includes, similar to before, a first group 152 and a second group 154 positioned in a side-by-side relationship such that the terminal sides 156 are opposite each other. Each of the groups includes cells 157, vent holes 158 and bus bars 160 as previously described. A vent manifold 162 may be disposed between the port sides 156 of the groups. The vent manifold is in fluid communication with the vent bores 158 and is in fluid communication with a ventilation system (not shown) via an opening 166. The manifold 162 may include a housing defining a chamber 164 in fluid communication with the vent bores 158. Alternatively, the vent manifold may be a plurality of tubes with openings attached to the vent bores.

Claims

A traction battery assembly (50) comprising: first and second groups (54, 56) each having cells (60) with two terminals each on a terminal side (72) of the group (54, 56) and arranged such that the terminal sides (72) are opposite each other; and a thermal plate (88) disposed between the groups (54, 56) and in contact with the terminal sides (72) of the group (54, 56), wherein one terminal of a cell (60) in the first group (54) is mechanically and electrically coupled to one terminal of a cell (60) in the second group (56) via a bus bar (124), wherein another terminal of the cell (60) in the first group (54) is mechanically and electrically coupled to one terminal of another cell (60) in the second group (56) via another bus bar (122).The traction battery assembly (50) of claim 1, wherein each of the cells (60) further comprises a vent hole (70) disposed on the terminal side (72) of the group (54, 56).The traction battery assembly (50) of claim 2, wherein the thermal plate (88) defines a vent channel (100) in fluid communication with at least one of the vent holes (70).The traction battery assembly (50) of claim 1, wherein the cell (60) of the first group (54) and the cell (60) of the second group (56) are positioned immediately opposite each other.The traction battery assembly (50) of claim 4, wherein a larger side (62) of the cell (60) of the second group (56) is disposed against a larger side (62) of the other cell (60) of the second group (56).A traction battery assembly (50) comprising: first and second groups (54, 56) each having cells (60) with terminals on a terminal side (72) of the group (54, 56) and arranged such that the terminal sides (72) of the group (54, 56) are opposite each other, wherein a cell (60) of the first group (54) is mechanically and electrically coupled at one terminal via a first bus bar (124) to a coplanar cell (60) of the second group (56) and at another terminal via a second bus bar (122) to another cell (60) of the second group (56) adjacent to the coplanar cell (60); and wherein each of the first and second groups (54, 56) defines a longitudinal axis, and the longitudinal axis of the first group (54) is substantially parallel to the longitudinal axis of the second group (56); and wherein a major axis of the first bus bar (124) is substantially perpendicular to the longitudinal axes of the groups (54, 56).The traction battery assembly (50) of claim 6, further comprising a thermal plate (88) disposed between the first and second groups (54, 56) and engaging the terminal side (72) of each group (54, 56).The traction battery assembly (50) of claim 7, wherein each of the cells (60) has a vent hole (70) disposed on the terminal side (72) of the group (54, 56).The traction battery assembly (50) of claim 8, wherein the thermal plate (88) defines a vent channel (100) in fluid communication with at least one of the vent holes (70).The traction battery assembly (50) of claim 6, wherein each of the cells (60) has a larger side (62) extending substantially perpendicular to the terminal side (72) of the group (54, 56), and wherein the cells (60) of the first and second groups (54, 56) are each arranged in a stack, wherein the larger side (62) of each of the cells (60) engages the larger side (62) of an adjacent cell (60).The traction battery assembly (50) of claim 6, wherein a major axis of the second bus bar (122) is angled 15 to 85 degrees, inclusive, with respect to the longitudinal axis of the first group (54).A traction battery assembly (50) comprising: first and second groups (54, 56) each having a plurality of cells (60) having a pair of opposing larger sides (62) and arranged in a stack such that the larger sides (62) of adjacent cells (60) are opposed to each other, wherein each of the cells (60) has terminals on a terminal side (66) of the cells (60) extending between the larger sides (62), wherein a first cell (60) of the first group (54) and a second cell (60) of the second group (56) are coplanar with respect to each other and arranged such that the terminal sides (66) of the cells (60) are opposed to each other, and the first cell (60) is mechanically and electrically coupled to the second cell (60) by a first bus bar (124), and mechanically and electrically coupled to a third cell (60) by a second bus bar (122), and wherein the third cell (60) is in the second group (56) and adjacent the second cell (60); and wherein a major axis of the first bus bar (124) is substantially coplanar with the first and second cells (60).The traction battery assembly (50) of claim 12, further comprising a thermal plate (88) disposed between and contacting the terminal sides of the first cell (60) and the terminal sides (66) of the second and third cells (60) opposite thereto.The traction battery assembly (50) of claim 12, wherein a major axis of the second bus bar (122) is offset with respect to the major axis of the first bus bar (124) by an angle that is 5 to 85 degrees, inclusive.The traction battery assembly (50) of claim 13, wherein the thermal plate (88) defines a vent passage (100), and at least one of the cells (60) further comprises a vent bore (70) disposed on the terminal side (66) of the cell (60) and in fluid communication with the vent passage (100).

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