Patent Description:
The document <CIT> relates to a battery module that includes a housing having a first protruding shelf along a first perimeter of the housing, a second protruding shelf along a second perimeter of the housing, where the first and second protruding shelves each include an absorptive material configured to absorb a first laser emission. The battery module also includes an electronics compartment cover configured to be coupled to the housing via a first laser weld, and a cell receptacle region cover configured to be coupled to the housing via a second laser weld. The electronics compartment cover has a first transparent material configured to transmit the first laser emission toward the first protruding shelf and the cell receptacle region cover has a second transparent material configured to transmit the first laser emission or a second laser emission toward the second protruding shelf.

The document <CIT> relates to a battery module that includes a housing having a first absorptive material configured to absorb a laser emission, a cover having a second absorptive material configured to absorb the laser emission, and a collar configured coupled to the housing and coupled to the cover via a laser weld. The collar includes a transparent material configured to transmit the laser emission through the collar and toward the housing or the cover.

The present disclosure relates generally to the field of batteries and battery modules. More specifically, the present disclosure relates to a method and system for fusing thermoplastic layers of a lithium ion battery module.

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, such as <NUM> Volt (V) or 130V systems. 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. Mild hybrids are typically 96V to 130V and recover braking energy through a belt or crank integrated starter generator. 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 and operates at a voltage below 60V. 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 12V systems 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.

As technology continues to evolve, there is a need to provide improved power sources, particularly battery modules, for such vehicles. For example, lithium ion battery modules are generally considered sensitive to environmental conditions. Accordingly, there is a need for lithium ion battery modules that are able to isolate internal components of such modules from the external environment.

The present invention relates to a method for bonding components of a lithium ion battery module according to independent claim <NUM>, wherein further developments of the inventive method are provided in the sub-claims <NUM> to <NUM>. The present invention further relates to a lithium ion battery module housing according to independent claim <NUM>, and a lithium ion battery module according to independent claim <NUM>.

The present disclosure relates to a method for bonding components of a lithium ion battery module that includes positioning an energy absorbing insert adjacent to a first thermoplastic layer of the lithium ion battery module and to a second thermoplastic layer of the lithium ion battery module. Energy is applied to the energy absorbing insert to melt the energy absorbing insert and thereby fuse the first thermoplastic layer to the second thermoplastic layer. The first thermoplastic layer is a transmissive or semi-transmissive layer configured to allow the energy the pass through the first thermoplastic layer for absorption by the energy absorbing insert.

The present disclosure also relates to a lithium ion battery module housing including a thermoplastic cover, a thermoplastic battery housing lid secured to the thermoplastic cover, and an energy absorbing insert positioned between the thermoplastic cover and the thermoplastic battery housing lid and forming at least a part of a plastic weld joint between the thermoplastic cover and the thermoplastic battery housing lid.

The present disclosure further relates to a lithium ion battery module having a plurality of lithium ion battery cells held within an enclosure. The lithium ion battery module also includes a battery module housing coupled to a lid, the battery module housing and the lid forming the enclosure. A plurality of electronics components are held within an electronics compartment formed by the lid and a cover of the lithium ion battery module. The plurality of electronics components are operatively coupled to the plurality of lithium ion battery cells. The battery module housing and the lid are joined by a first weld and the lid and the cover are joined by a second weld. The second weld is formed between the lid and the cover via an energy absorbing insert having an increased absorbance in the infrared portion of the electromagnetic spectrum relative to the battery module housing and the cover.

As set forth above, there is a need for enclosures for lithium ion battery modules to have a seal that isolates the internal components of the battery module from the environment. In this respect, 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.

In general, there are various techniques for bonding thermoplastics. Solvent bonding is a technique that uses solvent to dissolve adjacent surfaces of two thermoplastic components to be bonded such as to allow the material to flow together. Once the solvent evaporates, only the material-to-material bond is left. Another method for bonding thermoplastic involves one or more types of adhesives for bonding two thermoplastic components. Similar to solvent bonding, adhesives require a fluid type material to be added between the two thermoplastic components. This adds to the complexity and cost of manufacturing as the fluid adhesive must be carefully applied such as not to contaminate other portions of the thermoplastic components or elements of the apparatus. Further, certain thermoplastic materials such as polypropylene are notoriously difficult for adhesives to stick to, thereby limiting the usefulness of this adhesive based method for fusing thermoplastics together.

Another method for bonding two thermoplastic components together relies on using ultrasonic energy to heat and melt thermoplastics together. However, this process disadvantageously uses relatively large amounts of power and lacks precision application of the ultrasonic energy to a specific area of the thermoplastic.

It is now recognized that these shortcomings of traditional approaches may be overcome by the approaches described herein. For example, present embodiments include providing an energy absorbing insert that is positioned adjacent two transparent/semi-transparent thermoplastic components. Energy, such as laser energy, may be passed through a transparent thermoplastic component to the energy absorbing insert, which absorbs the energy. In response to such absorbance, the energy absorbing insert heats, and may melt and fuse the two adjacent thermoplastic components thereby creating a weld joint. In one or more embodiments, the energy absorbing insert is a thermoplastic. In one or more embodiments, more than two thermoplastic components are stacked onto each other with a respective energy absorbing insert sandwiched in between or adjacent to a pair of thermoplastic components.

As discussed herein, these processes may be particularly useful for lithium ion battery module construction due to the relatively high level of precision that is desired for optimal performance and lifetime. Indeed, the 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) subject to a wide variety of conditions and environmental stresses. 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 an 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).

To simplify the following discussion, the present techniques will be described in relation to a battery system with a <NUM> volt lithium ion battery and a <NUM> volt lead-acid battery. However, one of ordinary skill in art is able to adapt the present techniques to other battery systems, such as a battery system with a <NUM> volt lithium ion battery and a <NUM> volt lead-acid battery, systems that utilize high voltage (HV) lithium ion battery systems, stationary energy storage systems, and the like.

To help illustrate, <FIG> is a perspective view of an embodiment of a vehicle <NUM>, which may utilize a regenerative braking system. Although the following discussion is presented in relation to vehicles with regenerative braking systems, the techniques described herein are adaptable to other vehicles that capture/store electrical energy with a battery, which may include electric-powered and gas-powered vehicles.

As discussed above, it would be desirable for a battery system <NUM> to be largely compatible with traditional vehicle designs. Accordingly, the battery system <NUM> may be placed in a location in the vehicle <NUM> that would have housed a traditional battery system. For example, as illustrated, the vehicle <NUM> may include the battery system <NUM> positioned similarly to a lead-acid battery of a typical combustion-engine vehicle (e.g., under the hood of the vehicle <NUM>). Furthermore, as will be described in more detail below, the battery system <NUM> may be positioned to facilitate managing temperature of the battery system <NUM>. For example, in some embodiments, positioning a battery system <NUM> under the hood of the vehicle <NUM> may enable an air duct to channel airflow over the battery system <NUM> and cool the battery system <NUM>.

In other words, the battery system <NUM> may 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 component <NUM> supplies power to the vehicle console <NUM>, a display <NUM> within the vehicle, and the ignition system <NUM>, which may be used to start (e.g., crank) an internal combustion engine <NUM>.

Additionally, the energy storage component <NUM> may capture electrical energy generated by the alternator <NUM> and/or the electric motor <NUM>. In some embodiments, the alternator <NUM> may generate electrical energy while the internal combustion engine <NUM> is running. More specifically, the alternator <NUM> may convert the mechanical energy produced by the rotation of the internal combustion engine <NUM> into electrical energy. Additionally or alternatively, when the vehicle <NUM> includes an electric motor <NUM>, the electric motor <NUM> may generate electrical energy by converting mechanical energy produced by the movement of the vehicle <NUM> (e.g., rotation of the wheels) into electrical energy. Thus, in some embodiments, the energy storage component <NUM> may capture electrical energy generated by the alternator <NUM> and/or the electric motor <NUM> during regenerative braking. As such, the alternator <NUM> and/or the electric motor <NUM> are generally referred to herein as a regenerative braking system.

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> may enable 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>. Accordingly, when a <NUM> volt battery system <NUM> is used, the bus <NUM> may carry electrical power typically between <NUM>-<NUM> volts.

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

In some embodiments, the energy storage component <NUM> may include multiple battery modules to utilize multiple different battery chemistries. For example, the first battery module <NUM> may utilize a lead-acid battery chemistry and the second battery module <NUM> may utilize a lithium ion battery chemistry. In such an embodiment, the performance of the battery system <NUM> may 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 system <NUM> may be improved. In accordance with present embodiments, the lithium ion battery module may include a housing that is constructed using the thermoplastic bonding techniques described herein.

To facilitate controlling the capturing and storing of electrical energy, the battery system <NUM> may additionally include 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 energy storage component <NUM>, the alternator <NUM>, and/or the electric motor <NUM>. For example, the control module <NUM> may regulate 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>, determine a predicted temperature trajectory of either battery module <NUM> and <NUM>, determine predicted life span of either battery module <NUM> or <NUM>, determine fuel economy contribution by either battery module <NUM> or <NUM>, determine an effective resistance of each battery module <NUM> or <NUM>, control magnitude of voltage or current output by the alternator <NUM> and/or the electric motor <NUM>, and the like.

Accordingly, the control module (e.g., unit) <NUM> may include 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. Generally, the processor <NUM> may perform computer-readable instructions related to the processes described herein. Additionally, the processor <NUM> may be a fixed-point processor or a floating-point processor.

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. Additionally, as depicted, the control module <NUM> may be included separate from the energy storage component <NUM>, such as a standalone module. In other embodiments, the battery management system (BMS) may be included within the energy storage component <NUM>.

In certain embodiments, the control module <NUM> or the processor <NUM> may receive data from various sensors <NUM> disposed within and/or around the energy storage component <NUM>. The sensors <NUM> may include a variety of sensors for measuring current, voltage, temperature, and the like regarding the battery module <NUM> or <NUM>. After receiving data from the sensors <NUM>, the processor <NUM> may convert raw data into estimations of parameters of the battery modules <NUM> and <NUM>. As such, the processor <NUM> may render the raw data into data that may provide an operator of the vehicle <NUM> with valuable information pertaining to operations of the battery system <NUM>, and the information pertaining to the operations of the battery system <NUM> may be displayed on the display <NUM>. The display <NUM> may display various images generated by device <NUM>, such as a GUI for an operating system or image data (including still images and video data). The display <NUM> may be any suitable type of display, such as a liquid crystal display (LCD), plasma display, or an organic light emitting diode (OLED) display, for example. Additionally, the display <NUM> may include a touch-sensitive element that may provide inputs to the adjust parameters of the control module <NUM> or data processed by the processor <NUM>.

<FIG> depict example systems that may house battery modules having housings that are produced using the thermoplastic bonding techniques described herein. <FIG> depicts an embodiment of the first (lithium ion) battery module <NUM> constructed in accordance with the present disclosure. Further, while the lithium ion battery module <NUM> depicted in <FIG> includes many components that may be common to battery modules configured in accordance with the teachings herein, it should be noted that the illustrated module is provided as an example to facilitate discussion of certain aspects of the present disclosure, and is not intended to exclude the presence of other battery module features (e.g., a battery control module, service disconnects, terminals, and various thermal management features). Further, certain battery modules that utilize welds produced in accordance with the present disclosure may not include certain of the features described herein.

In the illustrated embodiment, a plurality of battery cells <NUM> each include a first terminal <NUM> and a second terminal <NUM> located at a terminal end <NUM> of the battery cell <NUM>. The terminal end <NUM> may be considered to be positioned opposite a base end <NUM> of the battery cell <NUM>, the base end <NUM> being the end of the battery cell <NUM> that is located proximate to a base <NUM> of the lithium ion battery module <NUM>. The terminal end <NUM> may be part of a lid or cover assembly that encloses a casing <NUM> of the battery cell <NUM>, and the casing <NUM> encloses the electrochemical elements of the battery cell <NUM> (e.g., the electrochemical cell and electrolyte). These electrochemical elements, during operation (and in particular during formation) of the battery cell <NUM>, may generate gases and include materials that may be sensitive to external environments. Further, while illustrated as prismatic battery cells, it should be noted that the approaches described herein may also be applied to other battery module configurations having other battery cell geometries and types, for example cylindrical battery cells and pouch battery cells.

While illustrated as being located on the same end of the battery cells <NUM>, in other embodiments, the first and second terminals <NUM>, <NUM> may be located at different sides of the battery cell <NUM>, such as one at the terminal end <NUM> and one at the base end <NUM>.

The illustrated lithium ion battery module <NUM> seals these battery cells <NUM> from the external environment with a battery housing <NUM>, which couples to the base <NUM>. While shown as separate components, in certain embodiments, the battery housing <NUM> and the base <NUM> may be integrally formed (e.g., molded, welded, fabricated) into a single piece into which the battery cells <NUM> are placed. The battery housing <NUM> and the base <NUM> may therefore define a cavity <NUM> for holding the battery cells <NUM>. The battery housing <NUM>, in general, protects the battery cells <NUM> from the external environment, and may maintain the position of each battery cell <NUM> relative to the other battery cells <NUM>.

A module cover <NUM> is placed over the housing <NUM> to enclose the lithium ion battery module <NUM>. In certain embodiments, the module cover <NUM> may house certain components, such as venting mechanisms for the battery module <NUM>, electronics, and so forth. Further, in certain embodiments, the module cover <NUM> may be coupled to the housing <NUM> in a different orientation than the orientation illustrated in <FIG>, depending on various design considerations (e.g., locations of module terminals, venting locations). In accordance with present embodiments, an energy absorbing insert <NUM> may be positioned between coupling surfaces of the module cover <NUM> and the module housing <NUM>.

The manner in which the module housing <NUM> and the module cover <NUM> are coupled may be further appreciated with reference to <FIG>, which is a block diagram of an example system for fusing thermoplastic using the energy absorbing insert <NUM> in accordance with embodiments of the disclosure. The system is generally referred to as system "<NUM>. " System <NUM> includes a first transmissive layer 72a and a second transmissive layer 72b, and the energy absorbing insert <NUM>. While two transmissive layers 72a, 72b and one energy absorbing insert <NUM> are shown in <FIG>, more than two transmissive layers and/or more than one energy absorbing insert <NUM> can be used in accordance with the present disclosure.

In one or more embodiments, the transmissive layer <NUM> is transmissive with respect to a particular band of the electromagnetic spectrum, such as certain wavelengths or bands of wavelengths of a laser. In certain embodiments, the energy absorbing insert <NUM> is an opaque or black polypropylene layer that is configured to absorb energy as described herein. By way of non-limiting example, the energy absorbing insert <NUM> is based on the parent material being welded. Carbon black is a material (e.g., a pigment) that can be used to make plastics, including polypropylene, black in color. Carbon black is also a good absorber of certain types of laser energy, even at the relatively low loading levels (e.g., <NUM>%-<NUM>% by weight) used in the molded parts described herein. Other materials (e.g., pigments) can be used to adjust the transmissivity (or absorbance) of the energy absorbing insert <NUM>.

In contrast, pigments used to make parts black yet retain their transmissivity cannot be carbon black, but certain black transmissive pigments may used in molding black transmissive parts. In one or more embodiments, the energy absorbing insert <NUM> is a rigid or semi-rigid (rigid but not inflexible, such as somewhat flexible or having sections that are flexible) layer or component that is configured to melt and/or become pliable when subjected to a particular type of laser energy. Thus, system <NUM> includes an energy source <NUM> for transmitting energy to one or more layers/components of system <NUM> as described herein.

For example, in one or more embodiments, the first transmissive layer 72a may be adjacent to a first side of the energy absorbing insert <NUM> while the second transmissive layer 72b is adjacent to a second side of the energy absorbing insert <NUM>. In one or more embodiments, the energy source <NUM> is a laser. When energy is applied to energy absorbing insert <NUM> by energy source <NUM>, energy absorbing insert <NUM> melts and fuses together first transmissive layer 72a and the second transmissive layer 72b, thereby creating a weld joint. Both transmissive layers 72a, 72b are configured to allow the energy from energy source <NUM> to pass through with no or negligible absorbance of the energy. In one or more embodiments, the energy from energy source <NUM> is applied to the energy absorbing insert <NUM> for less than two seconds to melt at least the portion of the energy absorbing insert <NUM> that is being exposed to the energy. In one or more embodiments, the wavelength is chosen based on the transmission spectrum of the plastic being welded. As one example, a <NUM> fiber laser, commonly referred to as a "<NUM> micron" laser, can be used. While polypropylene has an adequate transmissivity at this wavelength, other wavelengths closer to <NUM> microns may be more efficient. Thus, by way of example, the use of a <NUM> micron wavelength laser is also contemplated. Of note, the present embodiments are not limited to the use of <NUM> or <NUM> micron wavelength lasers. These values are provided only as examples that may be suitable for use with polypropylene. Other values can be used with polypropylene and with other materials.

<FIG> is a block diagram of another embodiment of the system <NUM> in accordance with an aspect of the present disclosure. The illustrated embodiment of the system <NUM> includes an absorbing layer <NUM> that is configured to absorb energy from the energy source <NUM>. In this embodiment, the absorbing insert <NUM> is positioned to fuse to first transmissive layer 72a and the second transmissive layer 72b, as described above, while absorbing layer <NUM> is positioned to fuse together with the second transmissive layer 72b upon absorbing enough energy from energy source <NUM> to melt a portion of absorbing layer <NUM>, thereby creating several weld joints. In one or more embodiments, the first transmissive layer 72a, the energy absorbing insert <NUM>, the second transmissive layer 72b and the absorbing layer <NUM> are composed of the same material. In one or more embodiments, this material is polypropylene.

In one or more embodiments, energy absorbing insert <NUM> is predefined shape such as to prevent blocking of all energy from energy source <NUM>. For example, in one or more embodiments, energy absorbing insert <NUM> overlaps only a portion of first transmissive layer 72a and/or the second transmissive layer 72b. For example, a surface area of the absorbing inert <NUM> is less than a surface area of the first transmissive layer 72a and/or surface area of the second transmissive layer 72b. In one or more embodiments, energy from the energy source <NUM> passes through one or more apertures in the energy absorbing insert <NUM>, thereby allowing energy from energy source <NUM> to reach absorbing layer <NUM>. In one or more embodiments, the thickness of energy absorbing insert <NUM> is less than <NUM>. In one or more embodiments, energy absorbing insert <NUM> is a ring shape or is configured to abut an opening/aperture. In one or more embodiments, energy absorbing insert <NUM> includes geometrical and/or non-geometrical portions, and/or one or more apertures.

According to one embodiment of the disclosure, a method for fusing thermoplastic is provided. Energy absorbing insert <NUM> is positioned adjacent to the first thermoplastic layer 72a and to second thermoplastic layer 72b. Energy is applied to energy absorbing insert <NUM> to melt energy absorbing insert <NUM> for fusing first thermoplastic layer 72a to second thermoplastic layer 72b. First thermoplastic layer 72a is one of a transmissive and semi-transmissive layer, configured to allow the energy the pass through first thermoplastic layer 72a.

According to one aspect of this embodiment, the energy is laser energy from energy source <NUM>. According to one aspect of this embodiment, the laser energy is infrared laser energy. According to one aspect of this embodiment, first thermoplastic layer 72a is a cover for an electronics housing for electronics. According to one aspect of this embodiment, the absorbing layer <NUM> is positioned adjacent a first side of second thermoplastic layer 72b. The first side is opposite a second side of second thermoplastic layer 72b that is adjacent energy absorbing insert <NUM>. The energy is applied to the absorbing layer <NUM> to fuse the absorbing layer <NUM> to second thermoplastic layer 72b. The energy is applied to the absorbing layer <NUM> passing through second thermoplastic layer 72b.

According to one aspect of this embodiment, second thermoplastic layer 72b is a battery housing lid that defines a portion of an electronics housing. According to one aspect of this embodiment, the energy absorbing insert <NUM> is semi-rigid in the absence of the application of energy to energy absorbing insert <NUM>. According to one aspect of this embodiment, the first thermoplastic layer 72a is one of a clear and translucent polypropylene and the second thermoplastic layer 72b is one of a clear and translucent polypropylene.

<FIG> is a partial overhead perspective view of one embodiment of the system <NUM> in accordance with certain embodiments of the present disclosure. In the embodiment of <FIG>, the system <NUM> includes the battery module housing <NUM>, which is coupled to a lid <NUM> and the cover <NUM>. The housing <NUM>, the lid <NUM>, and the cover <NUM> are all of thermoplastic construction. As illustrated, the energy absorbing insert <NUM> is positioned to absorb energy from the energy source <NUM> to couple the cover <NUM> to the lid <NUM>.

In the illustrated embodiment, the lid <NUM> is positioned adjacent and/or stacked on the battery module housing <NUM>, and the cover <NUM> is positioned adjacent and/or stacked on the lid <NUM>. The lid <NUM> is configured to cover a battery compartment of the housing <NUM>, and the cover <NUM> is configured to cover an electronics compartment <NUM> where various features such as the control module <NUM>, signal connectors, and so forth, are located. The electronics compartment <NUM> may be formed by both the lid <NUM> and the cover <NUM>.

In certain embodiments, the battery module housing <NUM> corresponds to the absorbing layer <NUM> as described above. Further, in certain embodiments, the lid <NUM> is one of the first or second transmissive layers <NUM>, such as the second transmissive layer 72b described above. In the illustrated embodiment, the energy absorbing insert <NUM> forms a ring positioned between the lid <NUM> and the cover <NUM>. In this respect, the cover <NUM> may correspond to the first transmissive layer 72a described above.

To seal the battery module <NUM>, energy from energy source <NUM> is applied to the battery module housing <NUM> through the lid <NUM> such that battery module housing <NUM> at least partially melts, and fuses together with the lid <NUM>. Further, energy from energy source <NUM> is applied to energy absorbing insert <NUM> though cover <NUM> to fuse the lid <NUM> to cover <NUM> by melting the energy absorbing insert <NUM>. In one or more embodiments, cover <NUM> is a cover for an electronics housing defined by both lid <NUM> and the cover <NUM>. The cover <NUM> is one of a transmissive and semi-transmissive layer, configured to allow the energy the pass through the cover <NUM>.

According to one aspect of this embodiment, the energy is laser energy from energy source <NUM>. According to one aspect of this embodiment, the laser energy is infrared laser energy. According to one aspect of this embodiment, the battery module housing <NUM> is positioned adjacent a first side of the lid <NUM>. The first side is opposite a second side of the lid <NUM> that is adjacent the energy absorbing insert <NUM>. Battery module housing <NUM> is configured to receive energy to melt battery module housing <NUM> for fusing battery module housing <NUM> to thermoplastic battery housing lid <NUM>. The energy is applied to battery module housing <NUM> passing through the lid <NUM>. According to one aspect of this embodiment, the energy absorbing insert <NUM> is semi-rigid in the absence of the application of energy to energy absorbing insert <NUM>. According to one embodiment, the cover <NUM> is one of a clear or translucent polypropylene. According to one embodiment, the lid <NUM> is one of a clear and translucent polypropylene.

<FIG> is a process flow diagram of an embodiment of a method <NUM> of coupling thermoplastic components, for example during construction of a lithium ion battery module (e.g., the battery module <NUM>). At block <NUM>, the energy absorbing insert <NUM> is positioned adjacent to the first thermoplastic layer 72a and to the second thermoplastic layer 72b (e.g., between them).

At block <NUM>, energy is applied to the energy absorbing insert <NUM> to fuse first thermoplastic layer 72a to the second thermoplastic layer 72b. In one or more embodiments, first thermoplastic layer <NUM> being one of a transmissive and semi-transmissive layer, configured to allow the energy the pass through first thermoplastic layer <NUM>. In one or more embodiments, the energy is laser energy.

Claim 1:
A method for bonding components of a lithium ion battery module (<NUM>) comprising:
- positioning an energy absorbing insert (<NUM>) adjacent to a first thermoplastic layer (72a) of the lithium ion battery module (<NUM>) and to a second thermoplastic layer (72b) of the lithium ion battery module (<NUM>), wherein the first thermoplastic layer (72a) is a transmissive or semi-transmissive layer that allows the energy to pass through the first thermoplastic layer (72a); and
- applying energy through the first thermoplastic layer (72a) to the energy absorbing insert (<NUM>), which absorbs the applied energy and melts the energy absorbing insert (<NUM>), thereby fusing the first thermoplastic layer (72a) to the second thermoplastic layer (72b).