BATTERY PACK WITH A BATTERY BACKPLANE ARRANGEMENT WITH INTEGRATED BUSBAR CONNECTIONS AND THERMAL MANAGEMENT FUNCTIONS

Abstract

Battery pack (18) for use with a heat transfer fluid supply, the battery pack (18) comprising: a plurality of battery modules (20) arranged in a series, each respective battery module (20) of the plurality of battery modules (20) having a corresponding positive and negative voltage terminal (46, 48); a plurality of end plates (40), each of which is attached to a corresponding battery module (20) of the plurality of battery modules (20), the positive voltage terminals (48) being partially covered by a corresponding end plate (40) such that the end plates (40) define a finger-safe barrier; and a backplane arrangement (30) connected to the plurality of battery modules (20) comprising: an elongated backplane body (30B) with outer longitudinal surfaces (33), wherein the elongated backplane body (30B) runs parallel to the row and defines two or more internal lines (32A, 32B, 32C);and a plurality of busbar assemblies (34) corresponding to the plurality of battery modules (20) and connected to the outer longitudinal surfaces (33), each of the respective busbar assemblies (34) being configured to interact with a corresponding positive or negative voltage terminal (46, 48) of a respective battery module (20); wherein the lines (32A, 32B, 32C) extend along a length of the elongated backplane body (30B) adjacent to the busbar assemblies (34) such that heat transfer fluid from the supply to and from the busbar assemblies (34) is conveyed through the lines (32A, 32B, 32C); characterized in that the finger-safe barrier is a U-shaped receptacle cast into one of the respective end plates (40).

Description

The present invention relates to a battery pack according to the preamble of claim 1, as is known essentially from WO 2017 / 181 282 A1. INTRODUCTION A battery pack with a capacity suitable for operating one or more electric drive motors or generators typically comprises several battery modules, each containing an array of electrochemical battery cells. In some battery cell configurations, relatively thin cathode and anode plates are enclosed in a foil pouch containing an electrolyte fluid, with positive and negative electrodes or cell terminals extending from opposite ends of the foil pouch. The individual cell terminals are electrically connected within a specific battery module, for example, by ultrasonic welding. The battery pack is then assembled by electrically connecting an application-specific number of battery modules via a voltage bus with positive and negative busbars.For example, several battery modules can be arranged on a flat battery compartment and connected in series, after which an outer cover is attached to the battery compartment to protect the battery modules. Battery packs, especially those of the high-voltage type described above, generate significant amounts of heat during continuous operation. Over time, this heat degrades the efficiency and overall structural integrity of the battery pack. Therefore, thermal management systems are employed to precisely control the battery pack's temperature. In a common thermal management system, heat transfer fluid is circulated to and from fins located between the battery cells. The battery modules can also be heated or cooled directly via contact with a conductive plate, which is also supplied with the heat transfer fluid. Fans, valves, coolers, radiators, and other components are controlled within a thermal management circuit to ensure the battery pack is maintained at a desired temperature. SUMMARY This document discloses a battery pack for use with an external heat transfer fluid supply, wherein the battery pack has a backplane arrangement that combines electrical busbar connections, i.e., connection points where the backplane is connected to the positive and negative terminals of the battery modules forming the battery pack, with a thermal regulation structure that directly cools or heats an area near these connection points. The use of the improved backplane arrangement described below is intended to provide a simple electrical "push-to-connect" backplane-to-battery-module interface characterized by the absence of screw connections, rivets, or other connection structures that require an operator to access the high-voltage bus. In this way, the interface is essentially "finger-safe" for all types of assembly and servicing.Furthermore, the integrated heat transfer structure of the backplane arrangement can reduce the overall size of the busbars, requiring less busbar area for heat radiation. Specifically, according to the invention, a battery pack is presented which is characterized by the features of claim 1 or of claim 7. The busbar assemblies, provided in a number equal to the number of battery modules (i.e., one busbar assembly per battery module), are connected to the outer longitudinal surfaces. Each busbar assembly engages with or connects to the voltage terminals of one of the respective battery modules. The internal conduits extend along the length of the elongated backplane body adjacent to the busbar assemblies, allowing the heat transfer fluid to and from the busbar assemblies via these conduits. The battery pack may include end plates attached to a corresponding end face of the battery modules.The end plates incorporate negative and positive electrical terminals configured to interact with a corresponding connector of one of the respective busbar assemblies, with engagement between the terminals achieved by inserting the electrical connections into or onto the respective voltage terminals. The positive voltage terminals of the individual battery modules are enclosed or protected within a finger-safe barrier defined by one of the respective busbar assemblies or the end plates. The negative and positive electrical terminals can optionally be configured as exposed bar or pin terminals and as U-shaped socket or socket terminals.In some embodiments, the busbar assemblies can be overmolded with the outer longitudinal surfaces of the backplane body or connected to them by an insulating tape, adhesive or other joining structure as part of a secondary operation. The battery pack may include cooling plates in fluid communication with the internal conduits, with these plates being positioned adjacent to the battery modules and configured to direct / guide heat transfer fluid into and out of the conduits. The lines can include parallel and adjacent first and second lines, with the first line carrying the heat transfer fluid into the battery modules at a first temperature, individually (i.e., not in series). The second line carries the heat transfer fluid out of the respective battery modules at a second temperature, where the second temperature is higher than the first temperature. According to a further embodiment, the internal channels comprise three channels: first and second channels running adjacent to the outer longitudinal surfaces, and a third channel extending between and parallel to the first and second channels. The first and second channels carry the heat transfer fluid at substantially the same temperature, while the third channel is configured to carry the heat transfer fluid at a temperature that is substantially higher or lower than these two. A backplane arrangement is also disclosed for use with the aforementioned battery pack, i.e., with battery modules arranged in one or more rows, each provided with positive and negative voltage terminals aligned between the rows, and each in fluid communication with a heat transfer fluid supply. The backplane arrangement includes an elongated backplane body with external longitudinal faces. The backplane body defines internal channels configured to carry heat transfer fluid from the heat transfer fluid supply, the channels extending along a length of the elongated backplane body. The number of busbar assemblies corresponds to the number of battery modules, with each busbar assembly connected to the external longitudinal faces of the extended backplane body.The busbar assemblies are configured for connection to the positive and negative voltage terminals of the battery modules. Internal lines carry the heat transfer fluid to and from the busbar assemblies to cool or heat them. A vehicle is also disclosed herein, comprising drive wheels driven by the engine torque, an electric machine configured to generate the engine torque, a heat transfer fluid supply, and a battery pack. The battery pack, electrically connected to the electric machine and fluidically connected to the heat transfer fluid supply, comprises a plurality of battery modules and the backplane arrangement described above. The modules are arranged in one or more rows, and each battery module has positive and negative voltage terminals and an end plate. The end plate partially covers the positive voltage terminal, thus forming a finger-safe barrier between an operator and a high-voltage bus of the vehicle. The aforementioned features and advantages, as well as further features and advantages, are easily apparent from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic perspective view of an exemplary motor vehicle with a battery pack containing several battery modules, the battery modules being constructed according to the present invention. Fig. 2 is a schematic perspective view of an exemplary battery pack that can be used as part of the motor vehicle of Fig. 1. Fig. 3 is a schematic perspective view of a pair of battery modules connected via a backplane according to the present invention. Figs. 4A and 4B are schematic perspective views of part of one of the battery modules of Fig. 3, representing a possible assembly option within the scope of the invention. Fig. 5 is a schematic perspective view of an installed backplane with an end face and an optional end plate of the battery modules shown in Fig. 3.Figure 6 is a schematic continuous view of an optional embodiment of the backplanes shown in Figures 2-5. DETAILED DESCRIPTION With reference to the drawings, where in the multiple views the same reference numbers refer to the same components, a motor vehicle 10 is shown in Fig. 1, comprising a powertrain 12 with a high-voltage battery pack 18. As described below with reference to Figs. 2-6, the battery pack 18 described herein uses a backplane arrangement 30 which integrates or combines the connectivity of the battery pack 18 with the thermal regulation, i.e., cooling or heating, of individual busbar arrangements used for this purpose. The battery pack 18 may, as shown, have a relatively flat, generally rectangular shape, or the battery pack 18 may be arranged in a T-configuration or other application-specific shape.The powertrain 12 can include an internal combustion engine 13 and one or more electric machines 14 in a hybrid electric embodiment, or it can dispense with the use of the engine 13 in a battery-electric embodiment that is powered exclusively by the battery pack 18. In both embodiments, the drivetrain 12 transmits the torque generated by the motor 13 and / or the electric machines 14 to a set of front drive wheels 16F and / or rear drive wheels 16R, or the motor torque of the electric machine 14 can be used exclusively for starting and idling the motor 13. Although the motor vehicle 10 is described below as an exemplary system that benefits from the battery pack 18 as configured according to the present invention, the battery pack 18 can easily be adapted for use in marine vessels, aircraft, rail vehicles, robots and mobile platforms, as well as in power plants and other stationary systems. The battery pack 18 can use lithium-ion, nickel-metal hydride, or other battery chemistry suitable for the application. For example, the battery pack 18 can include foil- or plate-shaped battery cells (not shown) arranged in a stack and connected in series to provide sufficient output power to supply energy to the electric machine 14. If the electric machine 14 is configured as a drive motor for rotating the drive wheels 16F and / or 16R and for propelling the motor vehicle 10, the battery pack 18 can arrange these battery cells in separate battery modules 20, as schematically shown in Fig. 2, to generate a direct current (DC) output voltage of 60–300 volts (VDC) or more. To achieve a relatively high output voltage, the battery modules 20 can be arranged in a specific geometric configuration, such as the flat configuration shown in Fig. 1 and Fig. 2.2 , arranged and connected in series via a high-voltage bus. This in turn connects the individual battery modules 20 to the power electronics and a thermal management system. The thermal management system is schematically represented with a liquid pump (P) configured to circulate heat transfer fluid (arrow 11) to and from the battery pack 18, with warmer or colder heat transfer fluid exiting the battery pack 18 through a cooler (C) 19 to regulate the temperature of the battery pack 18. Other components of the thermal management system are omitted for clarity, including directional and expansion valves, thermostats, radiators, heat exchangers, etc. Furthermore, while the associated power electronics are shown in Fig.If 1 is omitted, these components typically include an inverter module with pulse-width modulated (PWM) semiconductor switches to convert a DC voltage from the battery pack 18 into an AC voltage (VAC) to supply the electric machine 14, a DC converter or an auxiliary power module to reduce the voltage level from the battery pack 18 to an auxiliary level (e.g. 12-15 VDC) sufficient to supply electrical auxiliary systems on board the vehicle 10. Fig. 2 illustrates a rectangular configuration of the battery pack 18, as generally described above with reference to Fig. 1. In this exemplary embodiment, a plurality of battery modules 20, each having an end face 22, are arranged continuously in the parallel rows R1 and R2, whereas in other embodiments only one row R1 may be present. The battery pack 18 has a width (W) and a length (L), with each row R1 and R2 extending over the length (L). Additional rows can be added to increase the width (W), with an even number of rows being considered in the disclosed embodiments, although this is not necessary. As part of the battery pack 18, a backplane assembly 30 with an extended backplane body 30B is arranged between the parallel rows R1 and R2.The backplane body 30B, which in some embodiments can be manufactured from injection-molded plastic, can be straight / linear and parallel to the rows R1 and R2 along its length (L). However, the shape of the backplane body 30B ultimately depends on the geometry of the battery modules 20 and the battery pack 18, which is why the straight / linear configuration of Fig. 2 is only one possible geometric layout for the flat rectangular battery pack 18, with Figs. 4A and 4B showing alternative nonlinear shapes. In addition to supporting the busbar assemblies 34, the backplane body 30B defines a plurality of internal lines 32 in fluid connection with an external supply of heat transfer fluid, e.g., the pump 35 shown in Fig. 1, so that the heat transfer fluid 11 from Fig. 1 is conveyed to and from the battery packs 18 via the backplane assembly 30. The lines 32 can convey heat transfer fluid at a lower temperature, as indicated by arrow CC, to the busbar assemblies 34, whereby the heat is extracted and conveyed to a heat exchanger or cooler (see Fig. 1) as a warmer heat transfer fluid (arrow CH), e.g., in a closed thermal management circuit. In this way, the backplane assembly 30 combines the electrical connectivity of the busbars with the thermal management of the busbar assemblies 34. Referring to Fig. 3, a perspective side view of a pair of battery modules 20 depicts an end view of the backplane assembly 30. As shown, the busbar assemblies 34 are connected to the outer longitudinal surfaces 33 of the backplane assembly 30 and are evenly distributed along the length (L) of the backplane assembly 30. In the illustrated embodiment, a parallel pair of lines 32 is used to convey heat transfer fluid to and from the battery modules 20. The heat transfer fluid can flow through a plate 49 located adjacent to and beneath the battery module 20. In an exemplary cooling operation, a relatively cold heat transfer fluid (arrow CC in Fig. 2) can flow individually through one of the lines 32 into the battery modules 20, passing within the battery modules 20 via tubes, fins, etc.circulate, as is known in engineering, and at an increased temperature exit to the other line 32, as indicated by arrow CH. As described in more detail below, an end plate 40 can be attached to a corresponding end face 22 of a respective battery module 20. The end plates 40 include negative and positive voltage terminals 46 and 48, which are configured to interact with the corresponding electrical connectors 36 and 38 of the backplane assembly 30, in particular using a push-to-connect process characterized by the absence of fasteners. The positive voltage terminal 48 can be enclosed in or covered by a finger-resistant barrier cast into the material of the end plate 40. The contact engagement of the backplane assembly 30 and the battery modules 20 is achieved by pushing the backplane assembly 30 onto the battery module 20, or vice versa, in a push-to-connect manner, without requiring an operator to access the positive voltage terminal 48 of the battery module 20, for example.to install a fastening element between the battery module 20 and an exposed busbar. Figures 4A and 4B illustrate a possible installation of the battery module 20 on a backplane 130, the geometry of which differs from that of the backplane 30 in Figures 2 and 3. That is, while a perfectly straight or linear configuration may be desirable for manufacturing simplification, the battery pack 18 of Figure 1 may not possess such symmetry. Supports, power components, housing structures, or other intervening structures may necessitate a modification of the geometric shape of the backplane 130, one possible geometric modification being shown in Figures 4A and 4B. Fig. 4A shows the backplane 130 as it is mounted, for example, in a battery compartment (not shown), with a battery module 20 lowered towards the backplane 130. Near the longitudinal surface 33 of the backplane 130 facing the battery module 20, the backplane 130 includes or defines the electrical connectors 136 and 138. The end plate 40 covers and supports the positive voltage terminal 48 of the battery module 20, with terminals 48 and 46 on the non-exposed / opposite side of the end plate 40 being electrically connected to the various battery cells. The positive voltage terminals 48 can optionally be designed as recessed / U-shaped socket connectors which, as shown, are largely covered by the end plate 40, while the negative voltage terminal 46 can be a flat plug extension / connector extending parallel to the end surface 22 of the battery module 20 to the electrical mating connector 136. From the perspective of Figs. 4A and 4B, the bores 45 are also visible, defined by and extending through a side surface 47 of the backplane 130, i.e., between the longitudinal surfaces 33. These bores 45 can be connected to the battery modules 20, possibly via the plate 49, using suitable tube lengths 52 or 152, as best illustrated in Figs. 4A and 5, respectively. Thus, the battery module 20 can be easily pressed onto the backplane 130, as best illustrated in Fig. 4B, so that the electrical terminals 136 and 138 of the backplane 130 are pushed into or onto the mutual voltage terminals 46 and 48 of the battery module 20. With reference to Fig. 5, the end face 22 of a particular battery module 20 is shown as it might appear upon successful connection with the backplane 30. The busbar assemblies 34 surrounding the battery module 20 are then connected to another corresponding battery module 20 to complete the assembly of the battery pack 18 of Figs. 1 and 2. The tube 152 fluidically connects to the openings 54 in the backplane 30, thus connecting the plate 49 to the backplane 30. The busbar assemblies 34 are mounted to the longitudinal surfaces 33 of the backplane 30, for example, by a secondary operation using insulating tape or another suitable fastening structure 37, or by overmolding the busbar assemblies 34 onto the longitudinal surfaces 33. Overmolding is a manufacturing process in which a part is progressively cast from different materials, e.g.,The longitudinal surfaces 33 and the busbar assemblies 34 can be partially or completely covered with overmolding materials to securely fasten the busbar assemblies 34. Since the backplane 30 also defines the conduit 32 of Fig. 3, the heat transfer fluid is ultimately routed through it in close proximity to the busbar assemblies 34 to regulate their temperature. Fig. 6 illustrates a schematic end view of a backplane 230 according to an alternative embodiment. The backplane 230 defines three parallel and adjacent internal conduits 32A, 32B, and 32C, with conduit 32B being flanked by conduits 32A and 32C. The busbar assemblies 34 are connected to the longitudinal surfaces 33, i.e., mounted on the longitudinal surfaces as shown in Figs. 2, 3, and 5, or overmolded on the longitudinal surfaces 33 as shown in Figs. 4A and 4B. In the exemplary embodiment of Fig. 6, heat transfer fluid can flow in two different ways: at a relatively low temperature via the innermost line, i.e., line 32B, into the battery modules 20 and at a relatively high temperature from the battery modules 20 through the outermost lines 32A and 32C, or heat transfer fluid in line 32B can flow at a lower temperature relative to the outermost lines 32A and 32C. It may be advantageous to prioritize the cooling of the battery cells within the battery modules 20 over the cooling of the busbar assemblies 34, or vice versa, depending on the configuration of the battery pack 18. Therefore, the routing of the heat transfer fluid through the battery pack 18, including through the battery modules 20 and the backplane 230, can be modified, depending on the application, so that components with a higher cooling priority are supplied with heat transfer fluid at a lower temperature. That is, a warmer heat transfer fluid flowing through lines 32A and 32C with respect to line 32B can be even cooler than the busbar assemblies 34, with a temperature difference between a given busbar assembly 34 and the heat transfer fluid temperature in the adjacent line 32A or 32C that may ensure sufficient cooling of the busbar assemblies 34. The backplanes 30, 130, and 230 described above enable the integration of the electrical backplane and the thermal control structure of the battery pack 18 from Fig. 1 into a single structural element. Corresponding plug-socket interfaces ensure that no high voltage is present on exposed busbars of the busbar assemblies 34 before, during, or after the battery modules 20 are installed in the battery pack 18. The configurations described herein can also reduce the number of parts and minimize leakage compared to existing electrical and thermal management structures. Improved thermal control of the busbar assemblies 34 via the backplanes 30, 130, or 230 potentially reduces the size of the busbar assemblies 34. Regarding manufacturing capabilities, using a linear flow path, as shown in Fig. 2 and Fig. 3, allows for the reduction of the size of the busbar assemblies 34.As shown in Figure 3, the two conduits 32 of the corresponding backplane 30 are extruded, with the busbar assemblies 34 being attached to the backplane 30 in a secondary operation. If the flow path is nonlinear, the backplane 130 or 230 with the busbar assemblies 34 can subsequently be overmolded or attached in a secondary operation. The bores 45 shown in Figures 4A and 4B can also be introduced in a secondary operation or as part of the injection molding of the backplane 130 or 230. The design of the battery pack 18 ultimately determines the optimal assembly sequence. For example, if the battery modules 20 are first arranged in a battery compartment (not shown), the backplane 30, 130, or 230 can be lowered towards the battery modules 20 and the cables 32 and connected to them. Alternatively, the backplanes 30, 130, or 230 can be installed on the battery modules 20 in a first step before installation in the battery pack 18.

Claims

Battery pack (18) for use with a heat transfer fluid supply, the battery pack (18) comprising: a plurality of battery modules (20) arranged in a series, each respective battery module (20) of the plurality of battery modules (20) having a corresponding positive and negative voltage terminal (46, 48); a plurality of end plates (40), each of which is attached to a corresponding battery module (20) of the plurality of battery modules (20), the positive voltage terminals (48) being partially covered by a corresponding end plate (40) such that the end plates (40) define a finger-safe barrier; and a backplane arrangement (30) connected to the plurality of battery modules (20) comprising: an elongated backplane body (30B) with outer longitudinal surfaces (33), wherein the elongated backplane body (30B) runs parallel to the row and defines two or more internal lines (32A, 32B, 32C);and a plurality of busbar assemblies (34) corresponding to the plurality of battery modules (20) and connected to the outer longitudinal surfaces (33), each of the respective busbar assemblies (34) being configured to interact with a corresponding positive or negative voltage terminal (46, 48) of a respective battery module (20); wherein the lines (32A, 32B, 32C) extend along a length of the elongated backplane body (30B) adjacent to the busbar assemblies (34) such that heat transfer fluid from the supply to and from the busbar assemblies (34) is conveyed through the lines (32A, 32B, 32C); characterized in that the finger-safe barrier is a U-shaped receptacle cast into one of the respective end plates (40). Battery pack (18) according to claim 1, wherein an electrical connection between one of the busbar arrangements (34) and the positive and negative voltage terminals (46, 48) of one of the battery modules (20) is established exclusively by a push-to-connect operation. Battery pack (18) according to claim 1, wherein the busbar arrangements (34) are cast onto the outer longitudinal surfaces (33) of the backplane body (30B). Battery pack (18) according to claim 1, further comprising: at least one plate in fluid connection with the internal lines (32A, 32B, 32C), wherein the at least one plate is arranged adjacent to the battery modules (20) and is configured to guide the heat transfer fluid into and out of the internal lines (32A, 32B, 32C). Battery pack (18) according to claim 1, wherein the internal lines (32A, 32B, 32C) comprise parallel first and second lines (32A, 32B), wherein the first line (32A) carries the heat transfer fluid individually into the plurality of battery modules (20) at a first temperature, and the second line (32B) carries the heat transfer fluid out of the respective battery modules (20) at a second temperature, wherein the second temperature is higher or lower than the first temperature. Battery pack (18) according to claim 1, wherein the inner lines (32A, 32B, 32C) comprise parallel first and second lines (32A, 32B) extending adjacent to the outer longitudinal surfaces (33), and a third line (32C) extending between and parallel to the first and second lines (32A, 32B), wherein the first and second lines (32A, 32B) are configured to carry the heat transfer fluid at substantially the same temperatures, and wherein the third line (32C) is configured to carry the heat transfer fluid at a temperature that is substantially higher or lower than the substantially the same temperatures. Battery pack (18) for use with a heat transfer fluid supply, the battery pack (18) comprising: a plurality of battery modules (20) arranged in a series, each respective battery module (20) of the plurality of battery modules (20) having a corresponding positive and negative voltage terminal (46, 48); and a backplane arrangement (30) connected to the plurality of battery modules (20) and comprising: an elongated backplane body (30B) with outer longitudinal surfaces (33), the elongated backplane body (30B) extending parallel to the series and defining two or more inner lines (32A, 32B, 32C);and a plurality of busbar assemblies (34) corresponding to the plurality of battery modules (20) and connected to the outer longitudinal surfaces (33), each of the respective busbar assemblies (34) being configured to interact with a corresponding positive or negative voltage terminal (46, 48) of a respective battery module (20); wherein the lines (32A, 32B, 32C) extend along a length of the elongated backplane body (30B) adjacent to the busbar assemblies (34) such that heat transfer fluid from the supply to and from the busbar assemblies (34) is conveyed through the lines (32A, 32B, 32C); characterized in that the elongated backplane body (30B) is nonlinear such that a flow path of the heat transfer fluid through the lines (32A, 32B, 32C) along a length of the elongated backplane is nonlinear is.;

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