Patent Description:
A vehicle uses one or more battery systems. In particular, a vehicle (e.g., an electric vehicle, a hybrid vehicle) may use a lithium-ion (Li-ion) battery in place of or in addition to a more traditional lead-acid battery. 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, such as <NUM> Volt (V) or 130V systems. In some electric vehicles, the lithium-ion battery supplies a majority of or all of the power used to propel the vehicle.

Many design aspects are considered when using a lithium-ion battery. For example, it may be beneficial for a lithium-ion battery to fit in a similar space as a lead-acid battery. Additional design considerations may include weight, crush-resistance, heat transfer from the lithium-ion cells to prevent overheating, materials cost, cost of manufacturing, and ease of manufacturing. <CIT> relates to a battery housing for a battery module, comprising a plurality of exterior walls surrounding a base forming an internal section which is configured to receive one or more battery cells.

Many different manufacturing techniques can be used for assembling a battery housing. For example, a simple butt joint with alignment features (e.g., posts) may be used to couple a first housing portion to a second using portion. However, this method requires removal of excess adhesive from the outside of the joint and would increase manufacturing demands. Another method of coupling the housing components includes using an adhesive tape. However, adhesive tapes may not have sufficient bonding requirements for mechanical shocks, vibration, and temperature range over its life. Other manufacturing techniques are desired.

Additionally, a metal heat sink base may be coupled to the battery housing by overmolding the metal part with a plastic housing. This method relies on a strong chemical bond between the plastic and aluminum and, thus, requires additional expertise in bonding poly materials to metals. Additionally, this method of bonding may result in insufficient joint robustness at the plastic/aluminum joint. Other manufacturing techniques are also desired.

A battery module is accordingly disclosed. Summaries of various aspects are set forth below. The disclosure relates to batteries and battery modules. More specifically, the disclosure relates to lithium-ion battery cells that may be used in vehicles as well as other energy storage/expending applications.

The disclosure relates to a battery module including a housing having a first interior surface and a second interior surface opposite the first interior surface. The battery module also includes a battery cell assembly disposed within an interior space of the housing between the first and second interior surfaces. The housing also includes a base portion that functions as a heat sink to draw heat away from the cell assembly. The base portion can be a metal base or metal base plate. The base portion can be coupled to the plastic portion of the housing using an adhesive dispensed in a groove of the housing.

The disclosure also relates to a method for manufacturing a battery module. The method includes dispensing an adhesive in a groove on a perimeter of the bottom of the housing. Further, the method includes coupling the base portion to the housing using the dispensed adhesive.

The disclosure further discloses a battery housing having a frame portion with a first material and a first thermal conductivity, and a base coupled to the frame portion. The base includes a second material with a second thermal conductivity greater than the first thermal conductivity, thereby facilitating better heat transfer from battery cells to the base. The first material can include a polymeric material and the second material includes a metal. The second base can be in the form of a plate and/or include a cooling feature.

The disclosure also discloses a battery housing comprising an injection molded frame portion having a shelf comprising. Formed in the shelf can be a groove, a spillway, and a channel providing a pathway through the shelf from the groove to the spillway, thereby making the bonding operation between the base plate and the housing less messy. This may also limit or eliminate the need for a secondary manual cleaning process.

In some constructions, the groove includes a rectangular portion and an arcuate portion. Also in some constructions, the shelf further comprises, formed in the shelf a plurality of spillways, and a plurality of channels.

Various examples of embodiments of the systems, devices, and methods according to the invention will be described in detail, with reference to the following figures.

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. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

The battery systems described herein may be used to provide power to various types of electric vehicles (e.g., 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 has housing and a number of battery cells (e.g., Lithium-ion (Li-ion) electrochemical cells) arranged within the housing to provide particular voltages and/or currents useful to power a load (e.g., one or more components of a vehicle). As another example, battery modules in accordance with present embodiments may be incorporated with or provide power to stationary power systems (e.g., non-vehicle systems).

Again, the battery modules configured in accordance with present embodiments may be employed in any number of energy expending systems (e.g., vehicular contexts and stationary power contexts). To facilitate discussion, constructions of the battery modules described herein are presented in the context of advanced battery modules (e.g., Li-ion battery modules) employed in vehicles (e.g., xEVs). As used herein, the terms "battery" and "battery module" may be interchangeable.

With the foregoing in mind, <FIG> is a perspective view of a vehicle <NUM> having a battery system <NUM>. A more detailed view of an example battery system is described in <FIG>. As depicted, the battery system <NUM> includes an energy storage component <NUM>. The energy storage component is coupled to an ignition system <NUM>, an alternator <NUM>, a vehicle console <NUM>, and optionally to an electric motor <NUM>.

The battery system <NUM> may supply power to components of the vehicle's electrical system. In the depicted construction, the energy storage component <NUM> supplies power to the vehicle console <NUM> and the ignition system <NUM>, which may be used to start (e.g., crank) the internal combustion engine <NUM>. The energy storage component <NUM> may capture electrical energy generated by the alternator <NUM> and/or the electric motor <NUM>.

To facilitate capturing and supplying electric energy, the energy storage component <NUM> may be electrically coupled to the vehicle's electric system via a bus <NUM>. For example, the bus <NUM> enables the energy storage component <NUM> to receive electrical energy generated by the alternator <NUM> and/or the electric motor <NUM>. Additionally, the bus <NUM> may enable the energy storage component <NUM> to output electrical energy to the ignition system <NUM> and/or the vehicle console <NUM>.

Additionally, as depicted, the energy storage component <NUM> includes multiple battery modules. For example, in the depicted embodiment, the energy storage component <NUM> includes a lithium-ion (e.g., a first) battery module <NUM> and a lead-acid (e.g., a second) battery module <NUM>, which each includes one or more battery cells. In other constructions, the energy storage component <NUM> includes any number of battery modules. Additionally, although the lithium-ion battery module <NUM> and lead-acid battery module <NUM> are depicted adjacent to one another, they may be positioned in different areas around the vehicle <NUM>. For example, the lead-acid battery module may be positioned in or about the interior of the vehicle <NUM> while the lithium-ion battery module <NUM> may be positioned under the hood of the vehicle <NUM>. In some implementations, the energy storage component <NUM> includes multiple battery modules to utilize multiple different battery chemistries.

To facilitate controlling the capturing and storing of electrical energy, the battery system <NUM> additionally includes a control module <NUM>. More specifically, the control module <NUM> may control operations of components in the battery system <NUM>, such as relays (e.g., switches) within the energy storage component <NUM>, the alternator <NUM>, and/or the electric motor <NUM>. The control module <NUM> may regulate the amount of electrical energy captured/supplied by each battery module <NUM> or <NUM> (e.g., to de-rate and re-rate the battery system <NUM>), perform load balancing between the battery modules <NUM> and <NUM>, determine a state of charge of each battery module <NUM> or <NUM>, determine temperature of each battery module <NUM> or <NUM>, control voltage output by the alternator <NUM> and/or the electric motor <NUM>, and the like.

For the construction shown in <FIG>, the control module <NUM> includes one or more processors <NUM> and one or more memories <NUM>. More specifically, the one or more processors <NUM> may 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 memories <NUM> may 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 module <NUM> may include portions of a vehicle control unit (VCU) and/or a separate battery control module.

The lithium-ion battery module <NUM> may have any one of a variety of different shapes, sizes, output voltages, capacities, and so forth, and the present disclosure is generally intended to apply to different variations of the shapes and sizes of the modules illustrated in the figures. Keeping this in mind, <FIG> is a front top perspective view of one construction of a battery module <NUM>, which can be the lithium-ion battery module <NUM>.

The battery module <NUM> includes a first terminal <NUM> (e.g., a negative terminal) and a second terminal <NUM> (e.g., a positive terminal) that may be coupled to an electrical load (e.g., circuit). In other constructions, the battery module <NUM> has more than two terminals, to provide different voltages for different loads via connections across different terminal combinations.

The battery module <NUM> includes a housing <NUM> for packaging or containing a plurality of battery cells and other components of the battery module <NUM>. The housing <NUM> includes two end portions <NUM> and <NUM>, two side portions <NUM> and <NUM>, a top portion <NUM> (e.g., fitted with a top cover <NUM>), and a bottom portion <NUM>. <FIG> shows the top portion <NUM>, one <NUM> of the two end portions, and one <NUM> of the two side portions. The housing <NUM> may be polymeric (e.g., polypropylene, acrylonitrile butadiene styrene (ABS), a polystyrene (PS), a polyimide (PI), or another suitable polymer or plastic or combination thereof), or other suitable housing material or combination of materials. Examples of combination of materials are discussed below, such as with <FIG>.

<FIG> is an alternative view of the example construction of the battery module <NUM> and depicts the bottom portion <NUM> of the battery module <NUM>. In this example construction, the bottom portion <NUM> includes a base portion <NUM> (may also be referred to simply as a "base") made of metal (e.g., aluminum) rather than the same polymer or plastic material of the housing <NUM>. The base portion <NUM> is shown as being a plate (may also be referred to as a "base plate"). The base portion functions as a heat sink or cooling plate to draw heat away from the plurality of battery cells disposed within the battery module. The base portion <NUM> is described in more detail in conjunction with <FIG> below. While the shown base portion <NUM> is in the form of a plate, other shapes are envisioned for the base <NUM> including a base having cooling features (e.g., fins) for passive or active cooling.

<FIG> illustrates an exploded perspective view of an example construction of the battery module <NUM> of <FIG> and <FIG>. The battery module <NUM> includes the housing <NUM> that is sized to facilitate, among other things, placement of a plurality of battery cells <NUM> in a desired manner. The battery module <NUM> may include a number of battery cells <NUM>. The number of battery cells <NUM> can depend on the voltage and/or capacity requirements of the battery module <NUM>, the individual voltage and capacity of each battery cell, and the manner in which the battery cells <NUM> are coupled. Accordingly, the number and/or arrangement of battery cells <NUM> may be variable from what is shown depending on the desired power of the battery module <NUM> and/or the desired dimensions (e.g., length, width, and/or height) of the battery module <NUM>.

While any single type of battery cell may be utilized, the battery cells <NUM> used in the battery module <NUM> all have the same general shape (e.g., prismatic, cylindrical, pouch, or any other), the same electrochemistry (e.g., electrode active materials, electrolytes, additives), the same general dimensions (e.g., to within manufacturing tolerances), and other similar design features (e.g., electrical isolation). In the depicted construction, the battery module <NUM> includes a number of battery cells <NUM> sufficient to enable the battery module <NUM> to provide a 48V output, though the battery module <NUM> may output other voltages (e.g., <NUM> V) using different numbers and/or connections of battery cells <NUM>. In shown construction, the battery cells <NUM> consist of four groups of six battery cells.

As shown in <FIG>, the battery cells <NUM> are arranged in a cell stack <NUM>. While four cell stacks <NUM> are shown, in other constructions, the battery cells <NUM> may be arranged in one, two, three, or more cell stacks. Further, the one or more cell stacks <NUM> may be oriented vertically (e.g., in a columnar arrangement with respect to cell terminals) or horizontally (e.g., in a row arrangement with respect to cell terminals).

A spacer <NUM> may be used between each battery cell of the cell stack <NUM> to separate the battery cells from one another. In various constructions, an insulating or electrically isolating material (e.g., an additional type of spacer) or film is disposed around the conductive surfaces of the battery cells <NUM>. The cell isolation film may further require use of an adhesive.

The stacks <NUM> of battery cells <NUM> are inserted into an opening <NUM> of the housing <NUM>. The housing <NUM> is large enough to accommodate the desired number of battery cells <NUM> and other components. In the depicted construction, the housing <NUM> is divided into four quadrants. While four quadrants are depicted, various alternative housing arrangements should be understood as within the scope of this disclosure. The housing <NUM> also includes vehicle connection components, such as, but not limited to, positive and negative terminals <NUM> and <NUM> and a communication connector <NUM> (<FIG>). In various constructions, the terminals <NUM> and <NUM> may each be comprised of a bus bar <NUM> and a terminal post. As shown in <FIG>, the cells are provided on top of the base plate using an adhesive such as a layer of epoxy <NUM>. The layer of epoxy <NUM> reflects the four-quadrant division of the housing <NUM>.

The battery cells <NUM> described herein are prismatic battery cells, where a prismatic battery cell, as defined herein, includes a prismatic case <NUM> (<FIG>) that is generally rectangular in shape. In contrast to pouch cells, the prismatic casing is formed from a relatively inflexible, hard (e.g., metallic) material. However, it should be noted that certain constructions may incorporate pouch cells in addition to or in lieu of prismatic battery cells. In accordance with the shown constructions, each prismatic battery cell includes a prismatic cell casing <NUM>. The casing <NUM> includes a top casing portion <NUM> where a set of cell terminals <NUM> and <NUM> (e.g., positive and negative cell terminals) are located. One or more cell vents are also located on the top casing portion <NUM>. The cell casing <NUM> also includes a bottom casing portion <NUM> positioned opposite the top casing portion <NUM>. Sides <NUM> and <NUM> may be straight or rounded, and extend between the top and bottom casing portions in respective positions corresponding to the cell terminals <NUM> and <NUM>. First <NUM> and second faces, which may be flat (as shown) or rounded, couple the first and second sides at opposing ends of each cell.

As described above, the battery cell stacks are provided into the housing <NUM>, as shown in <FIG>, atop the layer of epoxy <NUM> as well as the metal base plate <NUM>. Conductors are then provided atop the battery cells <NUM> in order to transmit the power out of the terminals <NUM> and <NUM>. In the illustrated example, carriers <NUM> holding cell bus bars <NUM> are provided to the cells <NUM>. In some examples, the carriers <NUM> may hold electrical connection components as well as one or more control boards <NUM>. These electrical connection components may include, but are not limited to, a flexible printed circuit (FPC) for facilitating the electrical connections, a battery management unit (BMU), wire harnesses <NUM>, the one or more bus bars <NUM>, shunts, fuses <NUM>, relays <NUM>, vehicle connector plugs, terminals, and/or covers.

<FIG> depicts an example construction of the housing <NUM> with the base plate <NUM> attached. <FIG> is a more detailed exploded view of the housing <NUM> and base plate <NUM> than that of <FIG>. As shown in <FIG> and <FIG>, the example construction of the base portion (e.g., the base plate <NUM>) has a perimeter shape corresponding to the bottom portion <NUM> of the housing <NUM>. The shown housing <NUM> has a hybrid construction including an injection molded plastic part (e.g., a frame portion or simply frame <NUM>) and the base plate <NUM> (e.g., an aluminum sheet). The base plate <NUM> is coupled to the frame <NUM> using an adhesive <NUM>. The adhesive <NUM> is dispensed along a perimeter of the frame <NUM>. Alternatively, the adhesive <NUM> may be dispensed along a perimeter of the base plate <NUM>.

The construction of the housing <NUM> for the example battery module <NUM> differs from typical battery housings that have an integral bottom and a top that is sealed off with a similar material cover. In the example construction of the figures, an integral bottom is not included when the frame <NUM> is injection molded. Instead, an injection molded frame <NUM> that has the appearance of a "picture frame" is manufactured when it is produced by an injection molding tool. That is, a perimeter of the bottom <NUM> (<FIG>) of the plastic portion of the frame <NUM> is formed with picture-like edge in which the base plate <NUM> will later be positioned.

The adhesive <NUM> is dispensed into a groove <NUM> formed in an edge <NUM> (or shelf) and extending around the perimeter of the bottom <NUM> of the frame <NUM>. The base plate <NUM> is then placed onto the bottom <NUM> of the frame <NUM> of the housing <NUM>. The edge <NUM> acts as a shelf to receive the base plate <NUM>. When the adhesive <NUM> cures, the base plate <NUM> is bonded to the housing <NUM>. In some alternative example constructions, the base plate <NUM> may be coupled to the frame <NUM> of the housing <NUM> using a suitable mechanical fastener(s) (e.g., screw, bolt, clamp, etc.) and a sealing ring. However, using mechanical fasteners is typically perceived as less desirable than using other fastening methods because mechanical fasteners can puncture the cells <NUM> in a crush event.

In this example construction, the shape of the base plate <NUM> is substantially rectangular or square. The example base plate <NUM> also has a small cutout in one corner. The base plate <NUM> is sized to fit completely within the perimeter of the bottom <NUM> of the frame <NUM>. In other example constructions, the base portion <NUM> may be any size and shape that corresponds with the perimeter. The base plate <NUM> in this example construction is an aluminum sheet. Alternatively, other metals or thermally conductive materials, even including other polymeric materials, may be used for the base plate <NUM>. The base plate <NUM> acts as a heat sink (i.e., the path-of-least-resistance for heat in the battery pack to leave the system) to draw heat away from the plurality of battery cells disposed within the battery module. The base portion <NUM> is envisioned as having other designs distinct from a plate. For example the base can include cooling features (e.g., fins) for passive or active cooling.

<FIG> is a cross-sectional view of the housing <NUM> with the base plate <NUM> attached and battery cells <NUM> disposed in the housing <NUM>. As shown in <FIG>, the base plate <NUM> is attached to the housing <NUM> inside a wall <NUM> of the shelf <NUM>. A bottom surface <NUM> (e.g., exterior surface, exterior side) of the base plate <NUM> is completely exposed and not covered in any way by the plastic housing. On a top surface <NUM> (e.g., interior surface, interior side) of the base plate <NUM>, the battery cells <NUM> are coupled to the base plate <NUM> and held in place with an adhesive (e.g., epoxy <NUM>). Other than the epoxy <NUM>, no intervening components are positioned between the base plate <NUM> and the battery cells <NUM> for the shown construction. This construction facilitates better heat transfer from the battery cells <NUM> to the base plate <NUM>. Additionally, the example construction is an improvement over prior constructions that may imbed a metal plate in a plastic base of a housing because including only the metal plate <NUM> improves thermal conductivity between the battery cells <NUM> and the chassis of the vehicle <NUM>. The example construction is also lighter and more cost effective than using an aluminum die cast housing. Thus, the hybrid housing construction described herein balances improved thermal conduction of using the metal base plate <NUM> with a cost and weight savings of a plastic for the remainder of the housing.

In one construction, the battery cells <NUM> are bonded on the interior side <NUM> of the base plate <NUM> and the exterior side <NUM> is to be in contact with the metal chassis of the vehicle <NUM> when the battery module <NUM> is installed or positioned within the vehicle <NUM>. Accordingly, the base plate <NUM> will draw excess heat from the battery cells <NUM> and transfer heat to the chassis of the vehicle <NUM> via conductive heat transfer. The heat will further dissipate from the chassis via convective heat transfer.

In addition to providing improved heat transfer from the battery cells <NUM>, using an aluminum or other metal sheet as the base plate <NUM> for the housing <NUM> can improve mechanical robustness of the battery module <NUM>. The example construction including the metal base plate <NUM> improves crush resistance over a construction using a completely plastic housing. Crush resistance is improved in five of the six directions from which crush forces may act on the battery. As a result, a need for an additional cover for the battery is eliminated, thus saving additional cost, time, weight, and space within the vehicle <NUM>. The complexity of manufacturing the battery module <NUM> is also reduced by not needing and additional cover for the battery.

<FIG> is a more detailed cross-sectional view depicting the groove <NUM> in which the adhesive <NUM> is placed to couple the base plate <NUM> to the frame <NUM> of the housing <NUM>. The groove <NUM> is included around a perimeter of the frame <NUM> of the housing <NUM>. The groove <NUM> includes a semi-circle or arcuate profile <NUM> and is molded into the shelf <NUM> of the molded frame <NUM> of the housing <NUM> (i.e., during the injection molding process of the housing). The groove <NUM> also has a minimum depth, which can be dictated at least in part by the specified strength of the adhesive <NUM> being dispensed in the groove <NUM>. The adhesive <NUM> may be dispensed using a nozzle. The size of the nozzle dispensing the adhesive <NUM> can correspond with the width of the groove <NUM> or the arcuate profile <NUM> in which the adhesive <NUM> is being dispensed. While different nozzle sizes may be used, using a nozzle that is too small for the groove <NUM> may result in too little adhesive being dispensed. If too little adhesive is dispensed, the seal may be insufficient. Alternatively, using a nozzle that is too large may result in too much excess product being dispensed, which affects manufacturing since the excess product needs to be removed.

The example construction includes a small gap <NUM> adjacent to the groove <NUM> and between an edge <NUM> of the base plate <NUM> and the perimeter wall <NUM> of the housing <NUM>. The small gap <NUM> accommodates manufacturing tolerances of the base plate <NUM> and/or the housing <NUM> so that the base plate <NUM> will fit fully within the frame portion <NUM> of the housing <NUM> without interference. At the opening of the gap <NUM>, a lead-in chamfer <NUM> can be included to aid assembly of the base plate <NUM> and the housing <NUM>. The height <NUM> of the wall <NUM> and thickness <NUM> of the base plate <NUM> is such that the base plate <NUM> is always in contact with the vehicle chassis. In other words, a maximum wall height <NUM> will be less than a minimum base plate thickness <NUM> based on typical manufacturing tolerances. Thus, the base plate <NUM> protrudes out from the edge <NUM> of the frame portion <NUM> of the housing <NUM> by a distance <NUM> to ensure that the plate <NUM> has primary contact with the vehicle <NUM> rather than the housing <NUM>.

Any air gap between the chassis of the vehicle <NUM> and the base plate <NUM> may impart more thermal resistance. Thus, the base plate <NUM> is, preferably, as close contact with the vehicle chassis as possible to transfer heat through conduction.

The example battery module <NUM> allows for many possible modular configurations of the base <NUM>. For example, different types of plates may be used in place of the example base plate <NUM> (e.g., different metal plates, different thermally conductive plates). Additionally or alternatively, for more demanding performance, an active cooler or cooling plate (e.g., a cooler using liquid or forced air) may be included in the housing <NUM> attached to or in place of the base plate <NUM>.

The adhesive <NUM> is dispensed in excess (about <NUM>% more than necessary) to ensure the groove <NUM> is completely filled. Dispensing excess adhesive ensures there is sufficient adhesive to support the joint between the housing <NUM> and the base plate <NUM>. An insufficient amount of adhesive may lead to a weak spot in the joint. A weak spot makes the joint more susceptible to mechanical shock and vibration. A weak spot may also create a potential for a fluid leak path in the housing assembly. The battery module <NUM> should meet a certain level of water and air leak tightness to reduce hazards. Using excess adhesive mitigates the risk of potential leak paths forming in the housing assembly.

The example construction of the frame <NUM> is also formed with a plurality of small channels <NUM> adjacent to and intersecting the groove <NUM>. The small channels <NUM> are formed in the shelf <NUM>. The small channels <NUM> direct or channel overspill adhesive from the groove <NUM> to voids <NUM> (e.g., spillway void) also formed in the shelf. The adhesive flows when the base plate <NUM> is pressed onto the frame <NUM>. A detailed view of the channels <NUM> is shown in <FIG>. The channels <NUM> are equally spaced and provide paths between the groove <NUM> and the voids <NUM>. The voids <NUM> collect the spillover adhesive so that the adhesive <NUM> does not disperse in an uncontrolled manner out through the gap <NUM> before the adhesive <NUM> cures. Thus, the inclusion of the channels <NUM> and the voids <NUM> collect the spillover adhesive and makes the bonding operation between the base plate and the housing less messy, thereby eliminating the need for a secondary manual cleaning process. The inclusion of the channels <NUM> and the voids <NUM> may also prevent or reduce the likelihood that the spillover adhesive affects primary contact of the heat sink with the vehicle <NUM>. The voids is a substantial size to accommodate any excess adhesive applied.

Other methods of coupling the base plate <NUM> to the housing <NUM> may instead be used. For example, a simple butt joint with alignment features (e.g., posts) may be used to couple the plastic housing and the aluminum base plate. However, this method requires removal of excess adhesive from the outside of the joint and would increase manufacturing demands. Another method of coupling the base plate to the housing includes using an adhesive tape. However, adhesive tapes may not have sufficient bonding meet the requirements on for mechanical shocks, vibration, and temperature range over its life. Thus, the example construction using dispensed adhesive <NUM> has benefits over other methods of coupling the base plate <NUM> to the housing <NUM>.

Alternatively, the base plate may be coupled to the housing by overmolding the aluminum sheet into the bottom of the plastic part. This method relies on a strong chemical bond between the plastic and aluminum and, thus, requires additional expertise in bonding plastics to metals. Additionally, this method of bonding may result in insufficient joint robustness at the plastic/aluminum joint.

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.

As utilized herein, the terms "approximately," "about," "substantially", and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

It should be noted that references to relative positions (e.g., "top," "bottom," "side," "front," and "back") 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.

For the purpose of this disclosure, the term "coupled" means the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. Such joining may be permanent in nature or may be removable or releasable in nature.

Claim 1:
A battery housing (<NUM>) comprising:
- two end portions (<NUM>, <NUM>), two side portions (<NUM>, <NUM>), a top portion (<NUM>), and a bottom portion (<NUM>);
- a frame portion (<NUM>) having a first material with a first thermal conductivity; and
- a metal base (<NUM>) coupled to the frame portion (<NUM>), the metal base (<NUM>) having a second thermal conductivity greater than the first thermal conductivity,
wherein the metal base (<NUM>) is attached to the bottom portion (<NUM>) of the battery housing (<NUM>).