Heat sink fixation through plastic melting

A battery housing for a battery module is disclosed. The battery housing has a plurality of exterior walls surrounding a base forming an internal section which is configured to receive one or more battery cells. The internal section has a bottom surface. A heat sink is joined to the bottom surface of the battery housing by a plastic deformation of a portion of the housing. A cover encloses the internal section of the battery housing. A battery module and a method of installation of a heat sink in a battery housing are also disclosed.

BACKGROUND

The present disclosure generally relates to the field of batteries and battery modules. More specifically, the present disclosure relates to heat sinks. The present disclosure more specifically relates to heat sinks for batteries, such as lithium ion batteries.

A vehicle that uses one or more battery systems for providing all or a portion of the motive power for the vehicle can be referred to as an xEV, where the term “xEV” is defined herein to include all of the following vehicles, or any variations or combinations thereof, that use electric power for all or a portion of their vehicular motive force. For example, xEVs include electric vehicles (EVs) that utilize electric power for all motive force. As will be appreciated by those skilled in the art, hybrid electric vehicles (HEVs), also considered xEVs, combine an internal combustion engine propulsion system and a battery-powered electric propulsion system. The term HEV may include any variation of a hybrid electric vehicle. For example, full hybrid systems (FHEVs) may provide motive and other electrical power to the vehicle using one or more electric motors, using only an internal combustion engine, or using both. In contrast, mild hybrid systems (MHEVs) disable the internal combustion engine when the vehicle is idling and utilize a battery system to continue powering the air conditioning unit, radio, or other electronics, as well as to restart the engine when propulsion is desired. The mild hybrid system may also apply some level of power assist, during acceleration for example, to supplement the internal combustion engine. Further, a micro-hybrid electric vehicle (mHEV) also uses a “Stop-Start” system similar to the mild hybrids, but the micro-hybrid systems of a mHEV may or may not supply power assist to the internal combustion engine. For the purposes of the present discussion, it should be noted that mHEVs typically do not technically use electric power provided directly to the crankshaft or transmission for any portion of the motive force of the vehicle, but an mHEV may still be considered as an xEV since it does use electric power to supplement a vehicle's power needs when the vehicle is idling with internal combustion engine disabled and recovers braking energy through an integrated starter generator. In addition, a plug-in electric vehicle (PEV) is any vehicle that can be charged from an external source of electricity, such as wall sockets, and the energy stored in the rechargeable battery packs drives or contributes to drive the wheels. PEVs are a subcategory of EVs that include all-electric or battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicle conversions of hybrid electric vehicles and conventional internal combustion engine vehicles.

xEVs as described above may provide a number of advantages as compared to more traditional gas-powered vehicles using only internal combustion engines and traditional electrical systems, which are typically powered by a lead acid battery. For example, xEVs may produce fewer undesirable emission products and may exhibit greater fuel efficiency as compared to traditional internal combustion vehicles and, in some cases, such xEVs may eliminate the use of gasoline entirely, as is the case of certain types of EVs or PEVs.

In addition to use in vehicles (e.g., vehicles, boats, trucks, motorcycles, and airplanes), advances in battery technology and rechargeable batteries are more frequently being used in what may be referred to as stationary battery applications. Applications for stationary batteries, which are often used in backup or supplemental power generation, are becoming more widespread with improvements in rechargeable aspects of batteries and with the lowering of prices for such technology. For example, stationary batteries may be utilized for industrial and/or household applications. Such applications may include DC power plants, substations, back-up power generators, transmission distribution, solar power collection, and grid supply.

Batteries, such as lithium ion batteries, are sensitive to low and high temperatures. Thus, it is important to regulate the cells and battery packs to remain in a desired temperature range for optimum performance and life. It is also important to reduce uneven distribution of temperature throughout a battery pack, which could lead to reduced performance. Likewise, it is important to eliminate or reduce the potential for uncontrolled temperature buildup or thermal runaway. Accordingly, a device or system for thermal management is desired.

One common device for use in thermal management is a heat sink. Current devices use screws or other fixation devices or over-molding a heat sink in order to capture the heat sink in a plastic battery housing. Unfortunately, screws and fixation devices risk damaging the cell should an overheating event or impact event occur. Further, in known over-molding processes issues arise during the manufacturing process, namely, trying to retain a heat sink in place while over-molding the plastic battery housing. For example, molding pressures may cause the heat sink to shift in the molding tool.

Therefore, a need exists for a battery module, battery housing, and system having a heat sink, as well as a method of manufacturing or installation of a heat sink which meets the needs of thermal management and overcomes one or more of the deficiencies of prior devices and processes.

SUMMARY

Accordingly, a battery housing for a battery module is disclosed. The battery housing has a plurality of exterior walls surrounding a base forming an internal section which is configured to receive one or more battery cells. The internal section has a bottom surface. A heat sink is joined to the bottom surface of the battery housing by a plastic deformation of a portion of the housing. A cover encloses the internal section of the battery housing.

A battery module is also disclosed. The battery module comprises a battery housing having a plurality of exterior walls surrounding a base forming an internal section which receives one or more battery cells. The internal section has a bottom surface. A heat sink is joined to the bottom surface of the battery housing by a plastic deformation of a portion of the housing. A plurality of battery cells are seated on top of the heat sink in the internal section. A cover encloses the internal section and plurality of battery cells.

A method of installation of a heat sink in a battery housing for a battery module is also disclosed. The method includes the steps of: providing a battery housing comprised of plastic and having an internal section formed by a plurality of exterior walls surrounding a base, the internal section having a bottom surface; installing a heat sink on a heating fixture; moving a heating fixture with installed heat sink into the internal section of the battery housing; pressing the heat sink into the bottom surface while heating with the heating fixture to at least partially melt the plastic and affix the heat sink to the housing; and removing the heating fixture from the housing.

Accordingly, a heat sink and fixation method for a battery is provided which solves one or more of the deficiencies with existing devices. The heat sink and fixation method provides improved consistency of fixation of the heat sink to the battery housing. For example, the disclosed heat sink and fixation method may allow for the battery housing material to melt over the heat sink for robust connection between the heat sink and battery housing. Further, the disclosed in various embodiments may allow for ease of manufacture. In addition, the disclosed may allow for no extraneous fixation devices such as screws to be introduced into the battery housing, preventing risks of puncture and damage to battery cells (which may be a particular risk when the battery used is in a vehicle and an accident or impact occurs).

These and other features and advantages of devices, systems, and methods are described in, or are apparent from, the following detailed descriptions and drawings of various examples of embodiments.

It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary to the understanding of the invention or render other details difficult to perceive may have been omitted. For ease of understanding and simplicity, common numbering of elements within the numerous illustrations is utilized when the element is the same in different Figures. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION

Referring to the Figures, a heat sink, a battery housing, a battery module, a system, and a method for fixation of a heat sink in a battery and a battery housing are disclosed.

The battery, battery module, and battery systems described herein may be used to provide power to various types of electric vehicles (xEVs) and other high voltage energy storage/expending applications (e.g., electrical grid power storage systems). Such battery systems may include one or more battery modules, each battery module having a number of battery cells (e.g., lithium-ion (Li-ion) electrochemical cells) arranged and electrically interconnected to provide particular voltages and/or currents useful to power, for example, one or more components of a xEV. As another example, battery modules in accordance with present embodiments may be incorporated with or provide power to stationary power systems (e.g., non-automotive systems).

Based on the advantages over traditional gas-powered vehicles, manufactures, which generally produce traditional gas-powered vehicles, may desire to utilize improved vehicle technologies (e.g., regenerative braking technology) within their vehicle lines. Often, these manufacturers may utilize one of their traditional vehicle platforms as a starting point. In accordance with aspects of the present disclosure, since traditional gas-powered vehicles are designed to utilize 12 volt battery systems, a 12 volt or 48 volt lithium ion battery may be used to supplement a 12 volt lead-acid battery. More specifically, the 12 volt or 48 volt lithium ion battery may be used to more efficiently capture electrical energy generated during regenerative braking and subsequently supply electrical energy to power the vehicle's electrical system.

As advancements occur with vehicle technologies, high voltage electrical devices may also be included in the vehicle's electrical system. For example, the lithium ion battery may supply electrical energy to an electric motor in a mild-hybrid vehicle. Often, these high voltage electrical devices utilize voltage greater than 12 volts, for example, up to 48 volts. Accordingly, in some embodiments, the output voltage of a 12 volt lithium ion battery may be boosted using a DC-DC converter to supply power to the high voltage devices. Additionally or alternatively, a 48 volt lithium ion battery may be used to supplement a 12 volt lead-acid battery. More specifically, the 48 volt lithium ion battery may be used to more efficiently capture electrical energy generated during regenerative braking and subsequently supply electrical energy to power the high voltage devices.

To help illustrate,FIG.1is a perspective view of an embodiment of a vehicle10. As discussed above, it would be desirable for a battery system12to be largely compatible with traditional vehicle designs. Accordingly, the battery system12may be placed in a location in the vehicle10that may house a traditional battery system. For example, as illustrated, the vehicle10may include the battery system12positioned similarly to a lead-acid battery of a typical combustion-engine vehicle (e.g., under the hood of the vehicle10). Furthermore, as will be described in more detail below, the battery system12may be positioned to facilitate managing temperature of the battery system12. For example, in some embodiments, positioning a battery system12under the hood of the vehicle10may enable an air duct to channel airflow over the battery system12and cool the battery system12. While specific examples of locations are described, one of skill in the art will appreciate that variations thereon would also be acceptable for the purposes provided.

A more detailed view of the battery system12is described inFIG.2. As depicted, the battery system12includes an energy storage component13coupled to an ignition system14, an alternator15, a vehicle console16, and optionally to an electric motor17. Generally, the energy storage component13may capture/store electrical energy generated in the vehicle10and output electrical energy to power electrical devices in the vehicle10.

In other words, the battery system12may supply power to components of the vehicle's electrical system, which may include radiator cooling fans, climate control systems, electric power steering systems, active suspension systems, auto park systems, electric oil pumps, electric super/turbochargers, electric water pumps, heated windscreen/defrosters, window lift motors, vanity lights, tire pressure monitoring systems, sunroof motor controls, power seats, alarm systems, infotainment systems, navigation features, lane departure warning systems, electric parking brakes, external lights, or any combination thereof. Illustratively, in the depicted embodiment, the energy storage component13supplies power to the vehicle console16and the ignition system14, which may be used to start (e.g., crank) the internal combustion engine18.

Additionally, the energy storage component13may capture electrical energy generated by the alternator15and/or the electric motor17. In some embodiments, the alternator15may generate electrical energy while the internal combustion engine18is running. More specifically, the alternator15may convert the mechanical energy produced by the rotation of the internal combustion engine18into electrical energy. Additionally or alternatively, when the vehicle10includes an electric motor17, the electric motor17may generate electrical energy by converting mechanical energy produced by the movement of the vehicle10(e.g., rotation of the wheels) into electrical energy. Thus, in some embodiments, the energy storage component13may capture electrical energy generated by the alternator15and/or the electric motor17during regenerative braking. As such, the alternator15and/or the electric motor17are generally referred to herein as a regenerative braking system.

To facilitate capturing and supplying electric energy, the energy storage component13may be electrically coupled to the vehicle's electric system via a bus19. For example, the bus19may enable the energy storage component13to receive electrical energy generated by the alternator15and/or the electric motor17. Additionally, the bus19may enable the energy storage component13to output electrical energy to the ignition system14and/or the vehicle console16. Accordingly, when a 12 volt battery system12is used, the bus19may carry electrical power typically between 8-18 volts.

Additionally, as depicted, the energy storage component13may include multiple battery modules. For example, in the depicted embodiment, the energy storage component13includes a lithium ion (e.g., a first) battery module20in accordance with present embodiments, and a lead-acid (e.g., a second) battery module22, where each battery module20,22includes one or more battery cells110. In other embodiments, the energy storage component13may include any number of battery modules. Additionally, although the lithium ion battery module20and lead-acid battery module22are depicted adjacent to one another, they may be positioned in different areas around the vehicle. For example, the lead-acid battery module22may be positioned in or about the interior of the vehicle10while the lithium ion battery module20may be positioned under the hood of the vehicle10.

In some embodiments, the energy storage component13may include multiple battery modules to utilize multiple different battery chemistries. For example, when the lithium ion battery module20is used, performance of the battery system12may be improved since the lithium ion battery chemistry generally has a higher coulombic efficiency and/or a higher power charge acceptance rate (e.g., higher maximum charge current or charge voltage) than the lead-acid battery chemistry. As such, the capture, storage, and/or distribution efficiency of the battery system12may be improved.

To facilitate controlling the capturing and storing of electrical energy, the battery system12may additionally include a control module24. More specifically, the control module24may control operations of components in the battery system12, such as relays (e.g., switches) within energy storage component13, the alternator15, and/or the electric motor17. For example, the control module24may regulate amount of electrical energy captured/supplied by each battery module20or22(e.g., to de-rate and re-rate the battery system12), perform load balancing between the battery modules20and22, determine a state of charge of each battery module20or22, determine temperature of each battery module20or22, control voltage output by the alternator15and/or the electric motor17, and the like.

Accordingly, the control unit24may include one or more processor26and one or more memory28. More specifically, the one or more processor26may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general purpose processors, or any combination thereof. Additionally, the one or more memory28may include volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read-only memory (ROM), optical drives, hard disc drives, or solid-state drives. In some embodiments, the control unit24may include portions of a vehicle control unit (VCU) and/or a separate battery control module.

In accordance with the present disclosure, the housing100of the battery module20includes one or more covers102,104configured to seal or cover the housing100. For example, referring toFIG.4, the housing100may include a lateral cover102that fits over a lateral side106of the housing100, where the lateral side106of the housing100retains, for example, a printed circuit board (PCB) and other electrical components (not shown) of the battery module20. An upper cover104may be disposed over the upper side108of the housing100to seal or cover the upper side108of the housing100. The upper cover104of the housing100may include various features, such as but not limited to, a handle for transport and/or a vent path which allows the scape of gases or fluids, and the like (not shown).

In accordance with embodiments of the present disclosure, the battery module20may include a housing100(e.g., plastic housing) configured to retain electrochemical cells110(e.g., prismatic lithium-ion [Li-ion] electrochemical cells) within an inside of the housing100(seeFIG.3). The housing100illustrated and described herein may contain multiple stacks of prismatic lithium-ion (Li-ion) electrochemical cells110. The battery module20may include any number of electrochemical cells110(e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more electrochemical cells), any type of electrochemical cell (e.g., Li-ion, lithium polymer, lead-acid, nickel cadmium, or nickel metal hydride, prismatic, and/or cylindrical), and any arrangement of the electrochemical cells110(e.g., stacked, separated, or compartmentalized).

As will be discussed herein, battery elements or electrochemical cells110may be provided atop a heat sink112. The electrochemical cells110may include terminals114. The electrochemical cells110may be inserted into the housing100through the openings116in the upper side108of the housing100, and positioned within the housing100such that the terminals114of the electrochemical cells110are disposed in the opening. A bus bar carrier (not shown) may be disposed into the opening and may retain bus bars (not shown) disposed thereon, where the bus bars are configured to interface with the terminals114of the electrochemical cells110. For example, the bus bars may interface with the terminals114to electrically couple adjacent electrochemical cells110together. Depending on the embodiment, the bus bars may couple the electrochemical cells110in series, in parallel, or some of the electrochemical cells110in series and some of the electrochemical cells110in parallel. Further, certain of the bus bars may be configured to electrically couple the electrically interconnected group of electrochemical cells110with major terminals114of the battery module20, where the major terminals114are configured to be coupled to a load (e.g., component(s) of the vehicle10) to power the load. The electrochemical cells110may also include vents118configured to enable gases from within the electrochemical cells110to vent into the inside of the housing100in certain operating conditions (e.g., if a pressure within one or more individual electrochemical cell exceeds a cell venting pressure threshold of the corresponding one or more individual electrochemical cells).

The use of plastics may be desirable for use in lithium ion battery modules. For instance, plastics are usually considered lightweight, water resistant, and may be constructed to have strengths that approach or even exceed certain metal constructions. Thermoplastics are a type of plastic material that becomes pliable when subjected to a temperature above a predefined threshold (based on the particular thermoplastic material) to allow plastic deformation and melting. This temperature may be referred to as the glass transition temperature (Tg). When a thermoplastic is below its Tg, it is solid. Thermoplastics are generally considered to be resistant to shrinkage, durable, and strong. Accordingly, in one or more examples of embodiments, the battery module20may include a housing100that is constructed of thermoplastic.

Referring toFIGS.5-9, one or more examples of a battery housing100are shown. The battery housing100comprises an enclosure having a plurality of exterior walls120, e.g., four exterior walls, and a base122or bottom. In some examples of embodiments, the battery housing100may be divided into a plurality of battery compartments or sections124. In the illustrated embodiment, the battery housing100is divided into four internal sections124by a number of interior walls126. As shown, an internal section124is made up of at least two interior walls126or interior wall segments127, and an interior surface or portion121of the at least two exterior walls120or exterior wall segments. While four internal sections124are shown, it is understood that any number of internal sections may be provided, namely, one or more, without departing from the disclosure herein. The battery housing100may be comprised of material such as, but not limited to, polypropylene.

A heat sink112is provided on the base122or bottom surface128of an internal section124of the housing100. To this end, one or more heat sinks112may be provided in the battery housing100. In the illustrated examples, a heat sink112is shown along a bottom surface128of each internal section124. As shown inFIG.9, the heat sink112illustrated in the examples of embodiments shown inFIGS.5-9is generally a planar, flat plate having a width (w) and length (1) corresponding to the width and length of the internal section124, such that the heat sink112extends to the walls120,121,126,127forming the internal section124. That is, when installed in the housing100the heat sink(s)112are positioned along a bottom interior surface128of the battery housing100and span from and between the interior walls126and exterior walls120. The heat sink112may be constructed of known materials capable of delivering the functions of a heat sink. For example, the heat sink112may be an aluminum plate. However, it is understood that various materials may be used to accomplish these functions and the foregoing is presented as an example only.

In one or more examples of embodiments, the battery housing100may further comprise one or more, or a plurality of ribs130(seeFIG.5). In one or more examples of embodiments, the ribs130are formed integral with the housing100and may be formed of the same material as the housing100. A rib130extends along the bottom interior edge of one or more of the exterior walls120and bottom edge of one or more of the interior walls126. In the illustrated embodiment, a plurality of ribs130are provided in each internal section124. In one example, the ribs130are provided on opposing wall surfaces such that they are spaced apart and may be generally parallel to each other on opposite sides of the internal section124. However, it is understood that the ribs130may be provided at any location and orientation suitable for accomplishing the intended purposes. The ribs130retain or assist in retaining a heat sink112in place on the bottom surface128of the housing100. More specifically, the ribs130are plastically deformed ribs which retain the heat sink112in position. Namely, when the heat sink112is installed, the ribs130may generally have a partial “mushroom” shape which connects to the bottom surface128of the housing100, surrounds an edge (or both edges) of the heat sink112, and extends over a portion of the top surface of the heat sink112. In this manner, the ribs130fix the heat sink112completely to the housing100.

While specific examples of shapes and materials and locations are described, variations and combinations of suitable materials, shapes and configurations, should likewise be understood as within the scope of the disclosure.

As discussed herein, one or more battery cells110may be provided into each internal section124(see example shown inFIG.4). In one or more examples of embodiments, the battery cells110may be provided seated above or on top of the heat sink112. In some examples of embodiments, the cells110may also be electrically isolated from the heat sink112, for example, using an isolation component132. InFIG.11, an isolation component132is illustrated in cross-section. Generally, the isolation component132may be sheet or other device providing a separation between the battery cells110and the bottom surface128of the housing100and/or the attached heat sink112. This isolation sheet128may also impart certain structural advantages such as, but not limited to, more consistent attachment to the battery housing100.

Referring toFIGS.10-12, a system and method of installation of the heat sink112into the battery housing100described inFIGS.5-9will be discussed. Accordingly, a battery housing100may be provided. First, the heat sink112, which may be a planar plate, may be installed onto or attached to a heating fixture134. In various embodiments, the heating fixture134is a fixture or heater suitably sized and configured to deliver heat to sufficiently heat the heat sink112for the purposes disclosed herein. The heating fixture134may be heated to a suitable temperature to heat the heat sink112plate to a temperature which may induce at least partial melting or plastic deformation of the housing material in the internal section124(such as for example a rib130or surface128or wall120,126). The melting temperature may be a temperature sufficient to heat the plastic or thermoplastic but not warp the heat sink112. For example, in various embodiments, the heating element may be at least 100 degrees Celsius. The heat sink112is placed on the heating fixture134. In one or more examples of embodiments, the heating fixture134may be comprised of a tool-grade stainless steel block, although variations thereon which accomplish the purposes provided would also be acceptable. While specific examples are provided, one of skill in the art will appreciate variations thereon may also be acceptable.

Next, the heating fixture134and the plate or heat sink112may be provided into (e.g., lowered) into the battery housing100. The plate112and fixture134are provided together into a battery housing100and pressed into the battery housing100. As shown in the illustrated example ofFIG.10, the heat sink112remains attached to the fixture134when inserted into the battery housing100. Insertion is made into an internal section124of the battery housing100. The heat from the fixture134may then transfer through the plate (heat sink112) and into the battery housing100, melting the plastic (for example, but not limited to, polypropylene or thermoplastic), and creating a robust joint between the heat sink plate112and battery housing100. That is, the heating fixture134may at least partially melt the battery housing100in the internal section124, for example, the battery housing ribs130and/or bottom surface. As the heat sink112is provided in the battery housing100, the battery housing material may be understood to melt slightly, allowing for the plastic material, such as the rib, to “mushroom” over a portion of the top surface of the heat sink112or plastically deform and fasten the heat sink112in place. In some examples of embodiments, an amount of force may be applied by the fixture134and heat sink112plate being pressed into the battery housing100, toward the bottom of the housing100, which, along with the application of heat presses the plate into the bottom surface plastic and causes the melting rib to mushroom over the heat sink112. After a predetermined amount of time, the fixture134is then raised or removed from the housing100, leaving the heat sink112attached to the bottom of the battery housing100. In some examples of embodiments, an isolation component or sheet132may subsequently be provided to separate the heat sink112and battery element or cell(s)110.

The assembly of heat sink112to housing100described hereinabove, in various embodiments, simplifies the joint between the battery housing100and heat sink112. The consistent interface between the heat sink112and battery housing100also optimizes heat transfer from the heat sink112to the battery housing100and out to the external environment.

One or more alternative examples of embodiments are shown inFIGS.13-17with like elements including like reference numerals. In the alternative embodiments shown, a battery housing100having exterior walls120and a base122or bottom is illustrated. One or more interior walls126may also be provided, forming one or more internal sections124. In various embodiments, the battery housing100may also optionally include one or more ribs130, for example, but not limited to, bottom ribs130.

InFIGS.13-17, one or more alternative examples of a heat sink212are provided within the battery housing100, and in particular within the internal sections124. As illustrated, one or more heat sink(s)212are aligned along a bottom surface128of housing100or internal sections124. Referring toFIG.17, the heat sink(s)212may have a first wall segment236and an opposing second wall segment238, each segment extending at an angle from and spaced apart by a bottom segment240. Each wall segment236,238and the bottom segment240may be generally planar. The first wall segment236and second wall segment238may extend generally perpendicularly from the bottom segment240. In some examples, the respective segments236,238,240may be integrally connected; that is, formed as a single unit. Accordingly, the heat sink212may be generally U-shaped. As a result, when the heat sink212is inserted into the housing100as shown inFIGS.13-17, that first wall segment236and second wall segment238on the two sides of the heat sink212may abut or be positioned adjacent to the walls of the housing100making up an internal section124of the battery housing100. In the illustrated embodiment the first wall segment236is positioned against or abuts an interior portion121of the exterior wall120and the second wall segment238is positioned against or abuts a surface of segment127of the interior wall126. The first wall segment236and second wall segment238of the heat sink212may extend along at least a portion of the interior of each wall120,126. The first wall segment236and second wall segment238have a height which is shorter than the height of the exterior wall120.FIG.17illustrates four U-shaped heat sinks212provided into a battery housing100.

Referring toFIGS.18-20, a system and method of installation of the alternative examples of embodiments of a heat sink212into the battery housing100described inFIGS.13-17will be discussed. Accordingly, a battery housing100may be provided. Similar to the embodiments described in reference toFIGS.10-12, in step (A) first the heat sink212, which may be a U-shaped plate, may be installed onto or attached to a heating fixture134. Next, the heating fixture134and the heat sink212plate may be provided into (e.g., lowered) into the battery housing100. The heat sink212plate and fixture134are provided together into a battery housing100and pressed into the battery housing100. As shown in the illustrated example ofFIG.18, the heat sink212remains attached to the heating fixture134when inserted into the battery housing100. Insertion is made into an internal section124of the battery housing100. The heat from the fixture134may then transfer through the plate (heat sink212) and into the battery housing100, melting the plastic (for example, but not limited to, polypropylene), plastically deforming the material and at least partially affixing the heat sink212plate and battery housing100. In other words, the heating fixture134presses the bottom of the heat sink212into the plastic battery housing100. The heat transfer from the fixture134through the heat sink212melts the battery housing plastic to create a solid joinder or bond between the battery housing100and heat sink212.

However, unlike the embodiment shown inFIGS.10-12, in the presently described examples, as shown in step (B) a second heating fixture234may be introduced into the battery housing100. The second heating fixture234with a tapered profile is moved into the internal section124of the housing100and the heat sink212and forces the vertical walls or wall segments236,238of the heat sink212outwards through the same pressure and heat transfer method described above. As shown inFIG.18, the second heating fixture234may have a larger width than the first heating fixture134. The second heating fixture234may also have tapered sidewalls242which taper inwardly toward the insertion end244of the heating fixture. In the illustrated embodiment, only a portion of each sidewall242is tapered. The second heating fixture234taper and increased width enables the fixture234to press against the first and second segments236,238of the heat sink212, which are generally vertical walls in the illustrated examples, when the second fixture234is inserted (Note:FIG.18illustrates this concept in an exaggerated manner and shows the heat sink and fixture234elevated from the bottom of the internal section124for ease of visibility). Because of the taper, width, and heat, the fixture234forces the heat sink212first and second segments236,238outwards into battery housing material. That is, insertion of the second heating fixture234, while heated, presses the sidewalls or first wall segment236and second wall segment238of the heat sink212into the walls120,126of the battery housing100, e.g., the exterior wall120and interior wall126, allowing for plastic to plastically deform and spread or mushroom over a portion of the heat sink212. The heat sink212may then be attached or at least partially embedded into the walls of the battery housing100. The second heating fixture234may then be removed (seeFIG.19). Finally, in some examples of embodiments, an isolation component or sheet134may be provided to separate the housing100and/or heat sink212from an inserted battery element or cell110(seeFIG.19).

The heating fixture134,234carries the heat sink212and transfers heat into the battery housing100through the heat sink212. The heating fixture134,234, in various embodiments, may therefore comprise a block having two dimensions (w) (1) which are the same approximate dimensions as the heat sink212, or slightly larger than the heat sink212. In one or more examples of embodiments, the heating fixture234may have a varied profile (for example, the second heating fixture234as shown inFIG.18may have a tapered profile). The heating fixture134,234may comprise a solid steel block; however, other materials accomplishing the purposes provided should be contemplated as within the scope of this disclosure.

Accordingly, a battery housing100for a battery module20is provided. The battery housing100has a plurality of exterior walls120surrounding a base122forming an internal section124which is configured to receive one or more battery cells110. The internal section124has a bottom surface128. A heat sink112or212is joined to the bottom surface128of the battery housing100by a plastic deformation of a portion of the housing100. A cover encloses the internal section124of the battery housing100. The heat sink112or212being provided between the battery cells110and the housing base122.

In one or more examples of embodiments, the housing100comprises a plurality of interior walls126, wherein one or more exterior walls120and one or more interior walls126form the internal section124. In this regard, the housing100may also comprise a plurality of internal sections124, and a plurality of heat sinks112or212joined to the battery housing100in the plurality of internal sections124.

In one or more examples of embodiments, the heat sink112or212is joined to the bottom surface128by one or more plastically deformed ribs130. The one or more plastically deformed ribs130may extend over an edge and a portion of a surface of the heat sink112. In the examples of embodiments described herein the heat sink may be a planar plate112or alternatively may be a U-shaped plate212. In the examples of embodiments in which a U-shape heat sink212is provided a first wall segment236and a second wall segment238of the U-shape plate are at least partially embedded in a respective first sidewall120and second sidewall126of the internal section124of the battery housing100.

A battery module20is also disclosed. The battery module20comprises a battery housing100having a plurality of exterior walls120surrounding a base122forming an internal section124which receives one or more battery cells110. The internal section124has a bottom surface128. A heat sink112or212is joined to the bottom surface128of the battery housing100by a plastic deformation of a portion of the housing100. A plurality of battery cells110are seated on top of the heat sink112or212in the internal section124. A cover104encloses the internal section124and plurality of battery cells110. In one or more examples of embodiments, an isolation component132may be provided between the plurality of battery cells110and the heat sink112or212.

A method of installation of a heat sink112or212in a battery housing100for a battery module20is also disclosed. The method includes the steps of: providing a battery housing100comprised of plastic and having an internal section124formed by a plurality of exterior walls120surrounding a base122, the internal section124having a bottom surface128; installing a heat sink112or212on a heating fixture134; moving a heating fixture134with installed heat sink112or212into the internal section124of the battery housing100; pressing the heat sink112or212into the bottom surface128while heating with the heating fixture134to at least partially melt the plastic and affix the heat sink112or212to the housing100; and removing the heating fixture134from the housing100.

In one or more examples of embodiments, the internal section124of the battery housing100has one or more ribs130, and wherein the heating fixture134plastically deforms the one or more ribs130. In one or more alternative examples of embodiments, the heat sink212has a U-shape profile and further comprising the steps of: introducing a second heating fixture234into the battery housing100, the second heating fixture234having a tapered profile; wherein movement of the second heating fixture234into the battery housing100and heating presses first and second sidewalls236,238of the heat sink212into first and second walls120,126of the internal section124of the battery housing100, and at least partially embeds the heat sink212in the housing100; and removing the second heating fixture234from the housing100.

Accordingly, a heat sink and fixation method for a battery is provided which solves one or more of the deficiencies with existing devices. The heat sink and fixation method provides improved consistency of fixation of the heat sink to the battery housing.

For example, the disclosed heat sink and fixation method may allow for the battery housing material to melt over the heat sink for robust connection between the heat sink and battery housing. Further, the disclosed in various embodiments may allow for ease of manufacture. In addition, the disclosed may allow for no extraneous fixation devices such as screws to be introduced into the battery housing, preventing risks of puncture and damage to battery cells (which may be a particular risk when the battery used is in a vehicle and an accident or impact occurs).

The disclosed system and method may have a number of additional advantages.

For example, traditional methods of installing a heat sink include introducing undercuts into the interior walls of the battery housing, and installing an aluminum heat sink into the undercuts. In this traditional method, the heat sink is manufactured in a size which is larger than the internal section and must be flexed during insertion so that it can seat into the undercuts. In comparison, in the method described herein, there is no reliance on heat sink sheet flexing or the complication of introducing undercuts in the plastic battery housing. Therefore, the disclosed system and method may be understood as an improvement upon traditional methods which rely on aluminum flexing to engage with an undercut in the battery housing. The heat sink described herein does not require the use of additional fastening hardware or complicated over-molding. Moreover, the heat sink becomes integral with the plastic battery housing. The system disclosed also may ensure maximum heat transfer between the heat sink and the battery housing, and out to the external environment.

Accordingly, the battery module, battery housing, and system having a heat sink, as well as the method of manufacturing or installation of a heat sink described herein meet the needs of thermal management and overcome one or more of the deficiencies of prior devices and processes.

It should be noted that references to relative positions (e.g., “top” and “bottom”) in this description are merely used to identify various elements as are oriented in the Figures. It should be recognized that the orientation of particular components may vary greatly depending on the application in which they are used.

It is also important to note that the construction and arrangement of the system, methods, and devices as shown in the various examples of embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements show as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied (e.g. by variations in the number of engagement slots or size of the engagement slots or type of engagement). The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.

Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the various examples of embodiments without departing from the spirit or scope of the present inventions.

While this invention has been described in conjunction with the examples of embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or that are or may be presently foreseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the examples of embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit or scope of the invention. Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.

The technical effects and technical problems in the specification are exemplary and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.