Battery pack with overmolded busbars providing parallel cooling paths

Abstract

A battery pack includes battery cells and an interconnect board assembly (ICBA) having a dielectric ICB and parallel busbars. Cell tabs protrude from the edges of the cells and are coupled to the busbars. The dielectric ICB is connected to the busbar at one distal end of the busbar. The dielectric material of the ICB is overmolded onto the other distal end so that the ICB is wrapped around the busbar to form an overmolded end. The overmolded end is received in a slot of a bracket to form a direct parallel cooling path to a heat sink. A method of manufacturing a battery pack includes arranging the busbars in parallel, overmolding a dielectric material onto the ends of the busbars to form the overmolded ends, and attaching the busbars to a plastic ICB formed of the dielectric material. The ICBA is then attached to the bracket and the cells.

Description

[0001] introduction. Background Art

[0002] Circuits of the type commonly used to regulate the operation of rotating electrical machines, air conditioning compressors, and other high power loads typically include a high voltage power source in the form of an electrochemical battery pack. For example, an electric powertrain typically includes a lithium-ion or nickel metal hydride battery pack constructed from one or more battery modules. The electric motor is energized by discharging the individual battery modules to provide output torque to a coupled load.

[0003] A battery pack configured to power a vehicle propulsion system or another high voltage load contains an arrangement or stack of individual battery cells suitable for the application. In a typical battery cell, relatively thin cathode and anode plates are separated by a separator within an electrolyte fluid and sealed within an outer soft pack. The positive and negative electrode extensions or cell tabs of each constituent battery cell may protrude a short distance from the edge of the soft pack to enable the cell tabs to be conductively connected to a high voltage power busbar.

[0004] During sustained operation, high voltage battery packs tend to experience substantial levels of Joule heating. This heating is prevalent at or along the welded joints or joints that connect the individual cell tabs to the busbars of the high voltage bus. Over time, the heat generated at these and other locations within the battery pack can have a detrimental effect on the power efficiency and structural integrity of the battery cells. As an example of the latter, heat-induced degradation of polymer sealing materials around protruding cell tabs can allow trapped electrolyte fluid to leak from the battery pouch. Therefore, thermal management systems are used to closely regulate battery temperature, wherein such systems typically operate via controlled circulation of a suitable battery coolant into and out of the various battery cells. Summary of the invention

[0005] Disclosed herein is a battery pack and associated methods of constructing and cooling a battery pack having a disclosed construction. A battery pack, optionally embodied as one or more battery modules, is thermally connected to a heat sink, which in various embodiments may be a substantially planar cooling manifold or cooling plate, a housing or casing of the battery pack, or another suitable heat sink. Heat transfer to the heat sink typically occurs over a high resistance path from various cell tab-busbar interfaces through intervening materials of the battery pack. Therefore, current battery cooling methods can provide suboptimal cooling and potential battery pack degradation.

[0006] When constructing an interconnect board (ICB), the present teachings are intended to aid in temperature regulation of a battery pack by overmolding designated ends of a set of voltage bus bars with a dielectric material. As will be appreciated by one of ordinary skill in the art, an ICB is used to interconnect various battery cells and may also support sensors, processing chips, and other electronic components in the overall control and regulation of a battery pack.

[0007] In other words, the busbar and ICB are integrated together via an overmolding process, leaving the active / high current surface of the busbar exposed for subsequent conductive bonding of the cell tabs. At the same time, the dielectric material covering the far end of the busbar serves as part of the high voltage barrier between the busbar and the heat sink, while at the same time facilitating heat transfer to the heat sink via one or more brackets as described herein.

[0008] In an exemplary embodiment of a battery pack as described herein, the battery pack includes a housing, a plurality of battery cells arranged therein, an elongated bracket connected to a heat sink, and an ICB assembly (ICBA). In this particular embodiment, the ICBA has a set of parallel bus bars, each of which is conductively connected to one or more of the battery cells via corresponding battery cell tabs. The ICB of the ICBA is constructed of plastic or another dielectric material, some of which is overmolded onto the distal end of each corresponding one of the bus bars to form a plurality of overmolded ends. The overmolded ends extend at least partially into the bracket slots of the elongated bracket to form a cooling path from each bus bar into the heat sink. Thus, when the ICBA is racked to the battery cells and engaged with the heat sink via the elongated bracket, a plurality of parallel cooling paths from the parallel bus bars are created in this manner.

[0009] The overmolded ends of the busbars are bonded to the elongated brackets within the bracket slots using a thermal interface material (TIM). The TIM and dielectric material together form a high voltage barrier between the busbars and the heat sink.

[0010] In some embodiments, the elongated bracket is a single continuous bracket arranged along the perimeter edge of the heat sink, and the bracket slot is a single continuous bracket slot configured to receive the overmolded end portion therein. The single continuous bracket slot can have a predetermined shape suitable for holding the TIM, for example, a generally U-shaped, L-shaped, or V-shaped cross-section or other suitable cross-sectional shape.

[0011] In other embodiments, the elongated stent comprises a plurality of separated elongated stents, ie, shorter stent segments spaced a short distance apart from one another. In such embodiments, several smaller stent slots are individually configured to receive a different one of the overmolded ends therein.

[0012] The dielectric material of the overmolded end portion may optionally define corresponding windows or through-holes through which predetermined surface areas of the busbar are exposed.

[0013] In certain configurations, the battery pack may be electrically connected to a rotating electric machine of an electric powertrain and configured to energize rotation thereof.

[0014] Also disclosed herein is an ICBA for use with a battery pack having battery cells, wherein the battery cells have corresponding anode and cathode cell tabs. An embodiment of the ICBA includes a set of parallel busbars, each busbar having corresponding first and second distal ends. The busbars are configured to be conductively coupled to corresponding one or more cell tabs during assembly of the battery pack.

[0015] As described above, the ICBA includes an ICB constructed of a suitable dielectric material, the ICB being connected to each busbar at a respective first distal end. The dielectric material of the ICB is also overmolded onto each busbar so that the dielectric material is wrapped around the respective second distal end of each busbar to form a plurality of overmolded ends. The overmolded ends are configured to extend into the bracket slots during battery pack assembly to form a plurality of parallel cooling paths from each busbar into the heat sink.

[0016] A method for constructing a battery pack may include arranging a plurality of busbars in parallel, each of which in this embodiment may be constructed of a conductive material. The method includes overmolding a dielectric material onto a distal end of each busbar to form a plurality of overmolded ends, and then attaching the other distal end of each busbar to an ICB formed of a dielectric material. The ICBA may be connected to a battery cell. Thereafter, in other embodiments, the constructed battery pack may be connected to a motor.

[0017] The present invention provides the following technical solutions:

[0018] 1. A battery pack for use with a heat sink having a bracket coupled thereto, the battery pack comprising:

[0019] case;

[0020] a plurality of battery cells disposed within the housing; and

[0021] An interconnect board assembly (ICBA) having:

[0022] a set of parallel bus bars, wherein each bus bar of the set of parallel bus bars is conductively coupled to one or more of the battery cells via corresponding battery cell tabs of the battery cells; and

[0023] Interconnect Board (ICB) constructed from dielectric materials,

[0024] wherein the dielectric material is overmolded onto a distal end of each respective one of the busbars to form a plurality of overmolded ends, and wherein the overmolded ends extend into bracket slots of the bracket to form a cooling path from each busbar into the heat sink.

[0025] 2. The battery pack according to technical solution 1 further includes: a cooling plate thermally connected to the shell, wherein the radiator is the cooling plate.

[0026] 3. The battery pack according to technical solution 1, wherein the heat sink is the shell.

[0027] 4. A battery pack according to technical solution 1, wherein each of the overmolded ends is bonded to the elongated bracket within the bracket slot using a thermal interface material (TIM), so that the TIM and the dielectric material together form a high voltage barrier between the busbar and the heat sink.

[0028] 5. The battery pack according to technical solution 1 further includes the bracket, wherein the bracket is a single continuous bracket arranged along the peripheral edge of the heat sink, and wherein the bracket groove is a single continuous bracket groove configured to receive the multiple overmolded end portions therein.

[0029] 6. The battery pack according to technical solution 1 further includes the bracket, wherein the bracket includes a plurality of separate slender brackets, and the bracket slot includes a plurality of bracket slots, each bracket slot being configured to receive a different one of the overmolded ends therein.

[0030] 7. The battery pack according to technical solution 1, wherein the dielectric material of each respective one of the overmolded ends defines a corresponding through-hole, and a predetermined surface area of ​​the busbar is exposed through the through-hole.

[0031] 8. The battery pack according to technical solution 1, wherein the dielectric material is nylon or polypropylene.

[0032] 9. The battery pack according to technical solution 1, wherein the dielectric material is a thermoplastic resin or a polymer.

[0033] 10. The battery pack according to technical solution 1, wherein the battery pack is electrically connected to a rotating motor of an electric powertrain and is configured to excite its rotation.

[0034] 11. An interconnect board assembly (ICBA) for a battery pack having a plurality of cell tabs and an elongated bracket connected to a heat sink, the elongated bracket defining a bracket channel, the ICBA comprising:

[0035] a set of parallel bus bars, wherein each bus bar has a respective first distal end and a respective second distal end and is configured to be conductively coupled to a respective one or more of the cell tabs during assembly of the battery pack; and

[0036] An interconnect board (ICB) constructed of a dielectric material, wherein the ICB is connected to each bus bar at a respective first distal end and is overmolded onto each bus bar such that the dielectric material wraps around a respective second distal end of each bus bar to form a plurality of overmolded ends, and wherein the overmolded ends are configured to extend into the bracket slots during assembly of the battery pack to form a plurality of parallel cooling paths from each bus bar into the heat sink.

[0037] 12. The ICBA according to technical solution 10, wherein the dielectric material of each respective one of the overmolded ends defines at least one corresponding through-hole, and a predetermined surface area of ​​the busbar is exposed through the through-hole.

[0038] 13. An ICBA according to technical solution 12, wherein the at least one corresponding through hole includes a plurality of through holes having approximately the same size and shape.

[0039] 14. The ICBA of claim 10, wherein an extension of the ICB adjacent one of the overmolded ends comprises a rib configured to engage the elongated bracket.

[0040] 15. A method for constructing a battery pack, the method comprising:

[0041] Arranging a plurality of bus bars in parallel, wherein each bus bar is constructed of a sheet of conductive material and has a respective first distal end and a respective second distal end;

[0042] overmolding a dielectric material of a plastic interconnect board (ICB) onto a respective second distal end of each bus bar to form a plurality of overmolded ends; and

[0043] The respective first distal end of each busbar is attached to a plastic ICB to thereby form an ICB assembly of the battery pack.

[0044] 16. The method according to technical solution 15 further comprises:

[0045] providing a plurality of battery cells, wherein each respective battery cell of the plurality of battery cells has a battery cell tab protruding from one or more edges of the respective battery cell as an electrode extension; and

[0046] The battery cell tabs are conductively coupled to corresponding ones of the busbars to form a plurality of cell-to-busbar connections.

[0047] 17. The method according to technical solution 16 further comprises:

[0048] connecting an elongated bracket to the heat sink, the elongated bracket defining a bracket slot therein; and

[0049] A plurality of overmolded ends are inserted into the bracket slots to thereby engage the elongated bracket and form a plurality of parallel cooling paths between each of the plurality of cell-to-busbar contacts and the heat sink.

[0050] 18. The method according to Technical Solution 17, wherein the radiator is a cooling plate or shell of the battery pack.

[0051] 19. The method according to technical solution 18, wherein connecting the slender bracket to the heat sink includes welding or bonding the slender bracket to the edge of the cooling plate or the housing.

[0052] 20. The method according to Technical Solution 19 also includes: connecting the battery pack to a rotating motor of an electric transmission system.

[0053] The above features and advantages and other features and advantages will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic perspective view illustration of an exemplary motor vehicle having an electric propulsion system including a battery pack constructed in accordance with the present disclosure.

[0055] Figure 2 Can be used as Figure 1 A schematic perspective view illustration of a battery pack that is part of a motor vehicle or other high voltage system is shown.

[0056] Figure 3 Can be used as Figure 2 A schematic perspective view illustration of an interconnect plate assembly of a portion of a battery pack is shown.

[0057] Figure 4 yes Figure 2 A partially exploded perspective illustration of a portion of a battery pack is depicted.

[0058] Figure 5 yes Figure 3 Schematic side view illustration of an ICBA. DETAILED DESCRIPTION

[0059] Representative applications of devices and associated methods according to the present application are described in this section. Various representative embodiments are provided to provide background and aid in understanding the teachings described. Those skilled in the art will appreciate that various changes may be made and equivalents may be substituted for elements of the disclosed solutions without departing from the intended scope of the invention as described in the appended claims.

[0060] Referring to the drawings, wherein like reference numerals refer to like parts throughout the several views, Figure 1 The motor vehicle 10 is schematically depicted as having an electric powertrain 11. The electric powertrain 11 includes a high voltage battery pack (B HV ) 12. In some embodiments, the battery pack 12 may be constructed from one or more battery modules 12M. Figure 1 12M. In other embodiments, the battery pack 12 is not modular, i.e., is constructed and used as a single battery pack 12. Therefore, for the purposes of this disclosure, the terms "battery pack" and "battery module" are used interchangeably, wherein one or more battery modules 12M may be used as a battery pack 12 in different configurations.

[0061] Each battery module 12M as referenced herein Figure 2-5 The battery module 12M is configured as described in detail to provide multiple parallel direct cooling paths to a suitable heat sink located within or near the battery pack 12. Such paths coincide with high current areas associated with Joule heating within the battery module 12M and are connected from each cell-busbar joint 31 (see Figure 2 ) extends to such a heat sink, namely, a resident cooling plate 200 as shown in the non-limiting exemplary embodiment. The transferred heat is thereby dissipated from the battery pack 12.

[0062] Figure 1 The battery pack 12 can be used in some applications to excite the stator windings (not shown) of the rotating electric machine 14 of the electric drive train 11 on the motor vehicle 10, for example, a battery electric vehicle as shown or a hybrid electric vehicle that uses the torque from the electric machine 14 in combination with another prime mover 13, which is typically but not necessarily an internal combustion engine. Those of ordinary skill in the art will understand that the battery pack 12 and / or one or more battery modules 12M can be used as an on-board power source in other applications and for other purposes (for example, on other types of vehicles, such as but not limited to aircraft, ships or rail vehicles, or in non-vehicle applications, such as power plants, cranes, mobile platforms, robots, etc.). Therefore, Figure 1 The exemplary embodiment of FIG. 1 is intended to illustrate only one possible system use of the battery pack 12 / battery module 12M.

[0063] Each battery module 12M may include and / or share a corresponding one of the cooling plates 200 or other heat sinks disposed adjacent to or along a major surface of the battery module 12M. Although the cooling plate 200 is depicted as a typical configuration in which the heat sink is the cooling plate 200 and is coextensive with the underside or bottom of the battery module 12M, in other applications, the actual location of the associated heat sink may vary. Additionally, the battery pack 12 may have a relatively flat "flat" shape as shown, with any number of possible external shapes or aspect ratios, including Figure 1 In certain embodiments of the automotive vehicle 10 , this low profile configuration may be suitable for reducing packaging space.

[0064] As will be appreciated by those skilled in the art, battery cooling functions on motor vehicles 10 and other systems equipped with electric powertrains 11 typically route battery coolant (shown as FF in the figure) through and / or around individual battery modules 12M via a network of cooling pipes with the assistance of fans, pumps, valves, coolers, radiators, and other components. To further reduce the required packaging space and complexity, some cooling systems are designed to reduce the battery module temperature by positioning the battery module on or adjacent to a cooling plate, typically by Figure 1 Some configurations exclude direct contact with the cooling plate 200 and thus, for example, the housing or casing 20 (see Figure 2 ) may replace the cooling plate 200 or serve in addition to the cooling plate 200. However, given the unique internal construction of the battery module 12M and the configuration of a typical cooling plate, heat transfer is still not optimal. Therefore, the present disclosure is intended to address this and other issues within the battery pack 12, which has a battery pack 12 having a cooling plate such as Figure 2-5 One or more battery modules 12M of the configuration shown.

[0065] exist Figure 1 In a non-limiting embodiment, the electric powertrain 11 is controlled via associated powertrain control circuitry (not shown) to generate and transmit torque generated by the prime mover 13 and / or the rotary electric machine 14 to a driven load, which is Figure 1The motor 14 includes a front drive wheel 16F and / or a rear drive wheel 16R. Alternatively, when the prime mover 13 is embodied as an internal combustion engine, the motor torque from the motor 14 can be used only to start and activate the prime mover 13. The battery pack 12 in the motor vehicle 10 or other system can adopt lithium ion, nickel metal hydride or other high-energy battery chemistry suitable for the application. As an example and not limitation, the battery pack 12 may include foil soft pack type, plate type or can type battery cells, which are arranged in a cell stacking manner and electrically connected to provide an output voltage at a level sufficient to excite the motor 14, for example, 300VDC or higher, or 60VDC or higher in certain propulsion operations. Therefore, "high voltage" may have different meanings in different embodiments, and "high voltage" generally means a voltage level that exceeds the typical 12-15VDC auxiliary / low voltage level.

[0066] In order to achieve a relatively high output voltage, the battery modules 12M may be arranged in a specific geometric configuration, such as Figure 1 and 2 12M. The battery modules 12M are of a flat configuration and are interconnected using the high voltage bus of the motor vehicle 10. This connection connects the individual battery modules 12M to the power electronics and thermal management system. The simplified thermal management system is schematically shown as including a coolant pump (P) 17, which in this embodiment is configured to circulate battery coolant (arrows FF) to and from a cooling plate 200, which is adapted, as described below, and possibly through the battery modules 12M. The heat transfer fluid is then transferred out of the battery pack 12 through a cooler (C) 19 to help cool the battery pack 12, and reverse operation is also possible when it is necessary to warm the battery pack 12.

[0067] For simplicity of illustration, other common thermal management system components are omitted, including directional and thermal expansion valves, thermostats, radiators, heat exchangers, etc. In addition, although for simplicity of illustration, Figure 1 The associated power electronics are omitted, but such components typically include a power inverter module that uses pulse width modulation (PWM) controlled semiconductor switches to convert the DC voltage from the battery pack 12 to an alternating voltage (VAC) to power the motor 14, and a DC-DC converter or auxiliary power module that is used to reduce the voltage level from the battery pack 12 to an auxiliary (e.g., 12-15 VDC) level sufficient to power auxiliary electrical systems on the vehicle 10.

[0068] refer to Figure 2 For clarity of illustration, an exemplary embodiment of a battery module 12M is shown with the external dust cover and internal mounting plate removed. The battery module 12M includes an external housing or shell 20, within which a battery cell stack 22 is disposed. Figure 4As best shown and well known in the art, the cell stack 22 includes a plurality of battery cells 24, and thus the battery cells 24 are stacked or otherwise purposefully arranged within a housing 20, which in turn may have a nominal top wall, bottom wall, and side walls for a given orientation. Each respective battery cell 24 has a pair of cell tabs 124 forming separate cathode and anode electrode extensions of the respective battery cell 24, such as a pair of cell tabs located at opposite ends of the battery cell 24 in the illustrated configuration.

[0069] Brief reference Figure 3 The battery module 12M also includes an interconnect board assembly (ICBA) 25 as an integral part of its construction. According to the present disclosure, the ICBA 25 includes a plurality of parallel conductive busbars 26 of a high voltage bus. The busbars 26 may optionally be embodied as elongated metal plates having respective first and second distal ends E1 and E2 and respective longitudinal axes A. 26 , wherein the longitudinal axis A of the set of busbars 26 is 26 The busbars 26 are constructed of a suitable conductive material, such as copper and / or aluminum. Optionally, the busbars 26 may be plated with a thin layer of nickel, tin, or other element suitable for the application to facilitate welding and provide other possible performance benefits, such as improved wear and tear resistance, corrosion resistance, etc. Finally, the busbars 26 are conductively connected to the battery cell tabs 124 via their battery cell tabs 124. Figure 4 The battery cells 24 are connected to each other by welding, for example, via laser welding, ultrasonic welding or another suitable conductive joint process as will be understood by one of ordinary skill in the art.

[0070] Figure 2 The ICBA 25 also includes a flexible or rigid interconnect board (ICB) 28 constructed of a suitable dielectric / non-conductive material. As used herein, the dielectric material is also thermally conductive to facilitate heat transfer in accordance with the present teachings. A mounting flange 27 with corresponding mounting holes 29 may be included as part of the ICB 28 to enable the ICBA 25 to be securely secured to the Figure 2 The battery module 12M of the ICB 28. In various embodiments, the dielectric material can be a plastic, such as nylon or polypropylene. Thermally conductive plastic resins or polymers can be used in other embodiments. For example, additives such as graphite, graphene, or ceramic fillers can be used with the dielectric base material to further enhance the thermal conductivity of the ICB 28.

[0071] like Figure 2 and 3As shown, the ICB 28 is connected at a respective first distal end E1 to the busbars 26 overmolded therewith or overmolded thereto, for example, using suitable fasteners 30, such as screws, rivets, or posts. At the opposite distal ends E2 of the busbars 26, the dielectric material used to form the remainder of the ICB 28 is overmolded onto a designated portion of each busbar 26. Thus, when the ICB 28 is fully formed, the dielectric material is wrapped around the respective second distal end E2 of each busbar 26 to form a plurality of overmolded ends 32, the overmolded surface 28M of the overmolded end portions 32 forming a dielectric material layer on a lower surface area of ​​one of the busbars 26.

[0072] In certain embodiments, the dielectric material of the ICB 28 may be overmolded to define one or more windows or through-holes 34 that are proximate to each respective one of the overmolded end portions 32. In a non-limiting embodiment, the through-holes 34 of each bus bar 26 may include a plurality of side-by-side through-holes 34, which may be of substantially equal size as shown or of different sizes and / or shapes. The through-holes 34 extend through the overmolded surface 28M to form windows through the overmolded surface 28M, thereby exposing some surface area of ​​the bus bar 26 at the second distal end E2. As will be appreciated, the presence of the optional through-holes 34 may facilitate additional heat transfer from the bus bar 26 and to a thermal interface material (TIM) 42, which is optionally disposed within a bracket slot 40P of the elongated bracket 40, as described below with reference to FIG. Figure 5 Adjacent to some of the overmolded ends 32 , extensions 35 of the ICB 28 that are not overmolded to the protruding areas of the corresponding busbars 26 may be used for added position and structural support, such extensions 35 including ribs 136 that may be configured to engage the elongated brackets 40 .

[0073] Reference again Figure 2 The cooling plate 200 may be arranged along the outer surface 20-S of the battery module 12M and configured to conduct the battery coolant therethrough ( Figure 1 FF). The internal coolant manifold configuration of the cooling plate 200 is well known in the art and, therefore, for simplicity of illustration, is not further described herein. In embodiments where the cooling plate 200 is not available nearby, other heat sinks may be used in the manner described below, including but not limited to the above-described walls of the housing 20. As will be appreciated, this alternative approach may require busbars 26 and ICBs 28 of different shapes. Since, in typical use of the battery pack 12, the housing 20 rests on or is in thermal communication with the cooling plate 200, heat is absorbed by the housing 20 and ultimately dissipated to the cooling plate 200.

[0074] On the outside of the battery pack 12, there is a longitudinal axis A 40At least one elongated support 40 defines a corresponding support slot 40P (see Figure 5 ). In some embodiments, the elongated bracket 40 is a single continuous bracket 40 and can be constructed of a suitable rigid or flexible material, such as aluminum, plastic, thermoplastic, or flexible polymer. Such a bracket 40 will extend completely along the perimeter edge of the cooling plate 200 or along a similar edge of another heat sink (such as the housing 20). Alternatively, the elongated bracket 40 can be divided into multiple smaller brackets 140, as shown in a dashed format, for example, to reduce weight or provide a desired structural response.

[0075] In either embodiment, the elongated bracket 40 or 140 defines a corresponding bracket slot 40P, either as a single continuous bracket slot 40P, or as a plurality of discrete bracket slots 40P. Although a generally U-shaped slot or groove is depicted in the various figures, other shapes are contemplated as long as the void defined by such a bracket 40 or 140 is capable of retaining the TIM 42 and allowing the TIM 42 to cure from a liquid applied state. Exemplary alternative shapes include, but are not limited to, V-shaped and L-shaped brackets 40 or 140.

[0076] In the ICBA 25 ( Figure 3 ) connected or mounted to Figure 2 During the rest of the battery module 12M, each bracket slot 40P receives and engages the overmolded end 32 of the busbar 26 therein. Depending on the configuration of the bracket 40, this may require receiving Figure 3 All of the overmolded ends 32 of the busbars 26 are received in a single continuous bracket slot 40P, or a different one of the overmolded ends 32 is received in a corresponding one of the smaller brackets 140, possibly excluding the extension 35. Thus, a plurality of direct parallel cooling paths are formed between the busbars 26 and the associated heat sinks to facilitate cooling of the busbars 26 and the cell tabs 124 connected thereto.

[0077] refer to Figure 5In order to enhance heat transfer from the overmolded end 32 of the power bus 27 to the heat sink 300 (e.g., the housing 20 and / or the above-mentioned cooling plate 200), the TIM 42 can be positioned in the bracket groove 40P as shown. In different embodiments, the TIM 42 can be a thermally conductive glue, paste or pad, for example, a commercially available two-component epoxy adhesive with a thermal conductivity suitable for the application. An exemplary thermal conductivity range suitable for battery applications is 1.5-6 W / mK, the required thermal conductivity properties are application-specific, and therefore the range is illustrative rather than limiting. The TIM 42 can be applied to the bracket groove 40P and along the bracket groove 40P to partially fill the gap defined thereby, for example, an elongated groove or channel. Once the overmolded end 32 is inserted into the bracket groove 40P and engaged with the bracket 40, the TIM 42 and the overmolded surface 28M together form a high voltage barrier between the bus 26 and the heat sink 300.

[0078] As will be appreciated by those skilled in the art, the above teachings are helpful in allowing them to practice the method for constructing the above battery module 12M. An example embodiment of this method may include arranging a plurality of the above busbars 26 in parallel, that is, such that the longitudinal axis A of the busbar 26 is 26 exist Figure 3 The ICBA 25 is parallel to each other.

[0079] The method may also include Figure 3 The ICB 28 is overmolded onto the busbars 26 so that the ICB 28 is wrapped around the respective second distal end E2 of each busbar 26 to form a plurality of the overmolded ends 32 described above. Once this occurs, the method in this embodiment may include connecting the respective first distal end E1 of each busbar 26 to the ICB 28 to thereby form Figure 1 , 2 and the ICBA 25 of the battery module 12M shown in FIG4. Exemplary techniques for connecting the first distal end E1 include rivets, studs, and threaded fasteners, to name a few possibilities.

[0080] In some embodiments, the method may include connecting each of the plurality of battery cell tabs 124 (see Figure 2 ) is conductively coupled to a corresponding one of the plurality of bus bars 26. In this manner, a plurality of cell-bus bar joints 31 may be formed, for example by performing laser welding, conductive bonding, or ultrasonic welding processes to form the cell-bus bar joints 31.

[0081] Depending on the extent to which the various components or subassemblies of the battery module 12M are to be assembled in a housing or obtained in pre-assembled form, the method may include providing a heat sink 300, e.g. Figure 1 , 2, 4 and 5. As described above, the heat sink 300 according to the present disclosure includes or is connected to at least one bracket 40 or 140, and the bracket 40 or 140 defines one or more bracket slots 40P. The method may include installing the ICBA 25 with the rest of the battery module 12M, such as Figure 4 As shown by arrow A, and then the cell tab 124 is welded to the bus bar 26 (see Figure 2 ). After that, Figure 3 The overmolded end 32 of the battery cell 120 can be inserted into the bracket slot 40P as shown by arrow B to thereby form parallel cooling paths, i.e., one cooling path extending from each corresponding one of the battery-busbar connector 31 and the heat sink 300. In other embodiments, the order of connection to the heat sink 300 and welding of the cell tab 124 can be reversed.

[0082] The brackets 40 or 140 described above may be coupled to the heat sink 300 by the supplier / manufacturer in some manner such that the heat sink 300 already includes the pre-mounted brackets 40 or 140 as an integral part of the construction of the cooling plate 200. Alternatively, as part of the production process of the battery module 12M, the brackets 40 or 140 may be coupled to a heat sink 300 that lacks such brackets 40 or 140, such as by welding or conductively bonding the brackets 40 or 140 along the perimeter edge of the heat sink 300.

[0083] In any embodiment, Figure 5 The TIM 42 depicted in FIG. 4A can be applied to the bracket 40 or 140 to partially fill the bracket slot 40P. Additional structural support is provided for the curing of the applied TIM 42. Figure 3 The completed ICBA 25 is then inserted into the bracket slot 40P. Once the battery module 12M is constructed in this manner, the method may include connecting the battery module 12M to a load, such as in an exemplary embodiment of the motor vehicle 10. Figure 1 The rotating motor 14.

[0084] The solution disclosed herein facilitates direct cooling using passive cooling techniques Figure 2 The passive cooling technique is achieved by a specially adapted cooling plate 200 or other heat sink 300 and the integrated HV barrier features of the overmolded surface 28M and TIM 42. The present teaching provides a method to mitigate the Joule heating effect along the tab-busbar interface (including the cell-busbar joint 31) by multiple parallel direct thermal paths from the high current conductor to the heat sink 300.

[0085] As will be appreciated by those skilled in the art, this solution can help minimize temperature gradients across the battery module 12M and prevent Figure 2 and4 Due to the mechanical coupling of the ICBA 25 to the battery module 12M and the cooling plate 200, the installation of the ICBA 25 can be performed together with the assembly of the battery module 12M to help simplify manufacturing. For example, the use of the bracket 40 or 140 enables the bracket 40 or 140 to be used as a locating feature on which the ICBA 25 can rest during certain assembly or manufacturing steps.

[0086] In addition, the integrated electrical isolation of the aforementioned solution is flexible, depending on the corresponding requirements for the high voltage barrier requirements of the battery pack 12. For example, the thickness of the overmold layer 28M (see Figure 3 ) can vary, and the specific grade, material and / or dielectric strength of such layer 28M can also vary. The disclosed device is also Figure 1 That is, in some embodiments, once the TIM 42 hardens, and because the bracket 40 or 140 can be metal-bonded to the cooling plate 200 or other heat sink 300, the ICBA 25 and battery pack 12 are effectively reinforced, which in turn provides additional robustness, for example, during road shock / vibration in the non-limiting embodiment of the motor vehicle 10. Given the present teachings, one of ordinary skill in the art will readily appreciate these and other potential benefits.

[0087] Although the best mode for implementing the present disclosure has been described in detail, those skilled in the art to which the present disclosure relates will recognize various alternative designs and embodiments for practicing the present disclosure within the scope of the appended claims. In addition, the embodiments shown in the drawings or the features of the various embodiments mentioned in this specification are not necessarily to be understood as embodiments independent of one another. On the contrary, each feature described in one example of an embodiment can be combined with one or more other desired features from other embodiments, resulting in other embodiments that are not described in words or with reference to the drawings. Therefore, such other embodiments fall within the framework of the scope of the appended claims.

Claims

1. A battery pack for use with a heat sink, the battery pack comprising: a bracket configured to be coupled to the heat sink, wherein the bracket includes a pair of side walls extending outwardly from the heat sink and spaced apart such that the bracket defines a bracket slot between the side walls; case; a plurality of battery cells disposed within the housing; and An interconnect board assembly (ICBA) having: a set of parallel bus bars, wherein each bus bar of the set of parallel bus bars is conductively coupled to one or more of the battery cells via corresponding battery cell tabs of the battery cells; and An interconnect board (ICB) constructed of a dielectric material, wherein the dielectric material is overmolded onto the distal end of each respective one of the bus bars to form a plurality of overmolded ends, and wherein the overmolded ends extend between the side walls into the bracket slots such that the overmolded ends are concealed by the side walls and form a cooling path from each bus bar into the heat sink.

2. The battery pack according to claim 1, further comprising: A cooling plate is in thermal communication with the housing, wherein the heat sink is the cooling plate.

3. The battery pack according to claim 1, wherein: The heat sink is the housing.

4. The battery pack according to claim 1, wherein: Each of the overmolded ends is bonded to a bracket within the bracket slot using a thermal interface material (TIM) such that the TIM and the dielectric material together form a high voltage barrier between the busbar and the heat sink.

5. The battery pack according to claim 1, wherein: The bracket is a single continuous bracket disposed along a perimeter edge of the heat sink, and wherein the bracket slot is a single continuous bracket slot configured to receive the plurality of overmolded end portions therein.

6. The battery pack according to claim 1, wherein: The bracket includes a plurality of separate elongated brackets, and the bracket slot includes a plurality of bracket slots, wherein each of the bracket slots corresponds to a respective one of the plurality of separate elongated brackets, and wherein each of the bracket slots is configured to receive a different one of the overmolded end portions therein.

7. The battery pack according to claim 1, wherein: The dielectric material of each of the overmolded end portions defines a corresponding through-hole through which a predetermined surface area of ​​the corresponding busbar is exposed, and the corresponding through-hole is disposed within the interior of the bracket slot.

8. The battery pack according to claim 1, wherein: The dielectric material is nylon or polypropylene.

9. The battery pack according to claim 1, wherein: The dielectric material is a thermoplastic resin or a polymer.

10. The battery pack according to claim 1, wherein: The battery pack is electrically connected to the rotating electric machine of the electric powertrain and is configured to stimulate rotation thereof.

11. An interconnect board assembly (ICBA) for a battery pack, wherein: The battery pack includes a plurality of cell tabs, and wherein an elongated bracket is connected to a heat sink, the elongated bracket including spaced-apart side walls defining a bracket channel and an inlet to the bracket channel, the ICBA comprising: a set of parallel busbars, wherein each busbar has a respective first distal end and a respective second distal end and is configured to be conductively coupled to a respective one or more of the cell tabs during assembly of the battery pack, wherein an inlet of the bracket channel faces upwardly toward the busbars; and An interconnect board (ICB) constructed of a dielectric material, wherein the ICB is connected to each bus bar at a respective first distal end and is overmolded onto each bus bar such that the dielectric material is wrapped around a respective second distal end of each of the bus bars to form a plurality of overmolded ends, wherein the dielectric material of each of the overmolded ends defines at least one corresponding through hole through which a predetermined surface area of ​​the respective bus bar is exposed, and wherein the overmolded ends are configured to extend through the inlet and into the bracket slot during assembly of the battery pack to form a plurality of parallel cooling paths from each bus bar into the heat sink such that the at least one corresponding through hole is concealed in the bracket slot.

12. The ICBA of claim 11, wherein: The at least one corresponding through hole includes a plurality of through holes having approximately the same size and shape.

13. The ICBA of claim 11, wherein: An extension of the ICB adjacent one of the overmolded ends includes a rib configured to engage the elongated bracket.

14. A method for constructing a battery pack for use with a heat sink having a bracket coupled to the battery pack, wherein: The bracket includes a pair of spaced-apart side walls extending outwardly from the heat sink such that the bracket defines a bracket slot between the side walls, the method comprising: Arranging a plurality of bus bars in parallel, wherein each bus bar is constructed of a sheet of conductive material and has a respective first distal end and a respective second distal end; overmolding a dielectric material of a plastic interconnect board (ICB) onto a respective second distal end of each of the bus bars to form a plurality of overmolded ends; attaching a respective first distal end of each busbar to a plastic ICB to thereby form an ICB assembly of the battery pack such that the overmolded ends extend between the sidewalls into the bracket slots such that the overmolded ends are concealed by the sidewalls and form a cooling path from each of the busbars into the heat sink; providing a plurality of battery cells, wherein each respective battery cell of the plurality of battery cells has a battery cell tab protruding from one or more edges of the respective battery cell as an electrode extension; Conductively connecting corresponding battery cell terminals to corresponding bus bars to form a plurality of battery cell-bus bar joints; Wherein, the cooling path includes a plurality of cooling paths; connecting a bracket to the heat sink, the bracket defining a bracket slot therein; and A plurality of overmolded ends are inserted into the bracket slots to thereby engage the bracket and form a plurality of parallel cooling paths between the plurality of cell-to-busbar contacts and the heat sink.

15. The method according to claim 14, wherein: The heat sink is a cooling plate or housing of the battery pack.

16. The method according to claim 15, wherein: Connecting the bracket to the heat sink includes welding or bonding the bracket to the cooling plate or an edge of the housing.

17. The method according to claim 16, further comprising: The battery pack is connected to a rotating electric machine of an electric powertrain.

Images