Ultraviolet curable adhesive for electrode stacks

Abstract

Aspects of the present disclosure include ultraviolet curable adhesive reagents and methods of using the same for electrode stacks. An example vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a plurality of battery cells, each having an electrode stack. The electrode stack of each battery cell includes a plurality of battery foils separated by insulating members in a stacked configuration including alternating layers of battery foils and insulating members. The electrode stack of each battery cell also includes an ultraviolet curable adhesive agent. An ultraviolet curable adhesive agent is applied between the alternating battery foils and insulating member layers, thereby adhering the plurality of battery foils to the insulating member. The ultraviolet curable adhesive agent includes a multifunctional acrylate cross-linking agent and an initiator.

Description

Technical Field

[0001] The present disclosure relates to battery cell manufacturing and, more particularly, to an ultraviolet curable adhesive reagent for electrode stacks. Background Art

[0002] Manufacturing speed and product reliability are important factors in battery cell production. Many soft-packaged lithium ion batteries rely on an insulating member located between adjacent battery components. Typically, the insulating member takes the form of a continuous sheet of electrically insulating material that is folded over the battery components to form a stack. In one example, the electrically insulating material passes through a mechanism that produces alternating layers. In one example, the alternating layers are folded and pressed against the battery electrodes to form a "z-fold stack". Other systems can manipulate the structure to form a "jelly roll stack".

[0003] Once separated and a selected number of electrodes are formed, the stack is removed, secured, and stored for shipping. Given the nature of the stack, an incompletely secured fold may allow the electrodes to slide or become misaligned. This misalignment can be exacerbated when the stack is transported. Misalignment of the battery electrodes can have an adverse effect on battery efficiency. Summary of the Invention

[0004] In an exemplary embodiment, a vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a plurality of battery cells, each battery cell having an electrode stack. The electrode stack of each battery cell includes a plurality of battery foils separated by an insulating member in a stacked configuration that includes alternating layers of battery foils and insulating members. The electrode stack of each battery cell further includes an ultraviolet curable adhesive reagent. The ultraviolet curable adhesive reagent is applied between the alternating layers of battery foils and insulating members to thereby adhere the plurality of battery foils to the insulating member. The ultraviolet curable adhesive reagent includes a polyfunctional acrylate crosslinker and an initiator.

[0005] In addition to one or more of the features described herein, in some embodiments, the polyfunctional acrylate crosslinker includes a multi-dented acrylic alkyl ester.

[0006] In some embodiments, the polyfunctional acrylate crosslinker includes a multi-branched acrylic alkyl ester having N branches, where N is 1, 2, 3, or 4. In some embodiments, the polyfunctional acrylate crosslinker includes at least one of mono-branched ethyl acrylate, mono-branched methyl acrylate, di-branched diethyl acrylate, di-branched dimethyl acrylate, tri-branched triethyl acrylate, tri-branched trimethyl acrylate, tetra-branched tetraethyl acrylate, and tetra-branched tetramethyl acrylate.

[0007] In some embodiments, the initiator includes a photoinitiator, which includes at least one of peroxide, benzoyl peroxide (BPO), tert-butyl peroxide, azo compounds, azodiisobutyronitrile, phosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoylformate, benzophenone, and thioxanthone.

[0008] In some embodiments, the stacked structure includes a Z-shaped folded stacked structure having two or more electrode folds.

[0009] In some embodiments, an ultraviolet curable adhesive reagent is cured using an ultraviolet light source to fix the electrode stack.

[0010] In another exemplary embodiment, the ultraviolet curable adhesive reagent includes a polyfunctional acrylate crosslinking agent, which includes a multi-indent acrylate alkyl ester. The multi-indent acrylate alkyl ester includes a multi-branched acrylate alkyl ester having N branches. N is 1, 2, 3, or 4. The multi-indent acrylate alkyl ester further includes a photoinitiator having a weight ratio of initiator to monomer of 0.05 wt% to 10 wt%.

[0011] In some embodiments, the polyfunctional acrylate crosslinking agent includes at least one of ethyl acrylate with a single branch, methyl acrylate with a single branch, diethyl acrylate with two branches, dimethyl acrylate with two branches, triethyl acrylate with three branches, trimethyl acrylate with three branches, tetraethyl acrylate with four branches, and tetramethyl acrylate with four branches.

[0012] In some embodiments, the initiator includes a photoinitiator, which includes at least one of peroxide, benzoyl peroxide (BPO), tert-butyl peroxide, azo compounds, azodiisobutyronitrile, phosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoylformate, benzophenone, and thioxanthone.

[0013] In some embodiments, the ultraviolet curable adhesive reagent further includes an adhesion additive. In some embodiments, the adhesion additive includes a polymer having an unsaturated structure. In some embodiments, the adhesion additive includes at least one of styrene butadiene (SBR) and silicone.

[0014] In yet another exemplary embodiment, a method for manufacturing stacked electrodes may include forming an electrode stack that includes a plurality of cell foils separated by insulating members, in a stacked configuration that includes alternating cell foils and insulating member layers. The method may include applying an ultraviolet (UV)-curable adhesive reagent between the alternating cell foils and insulating member layers. The UV-curable adhesive reagent may include a polyfunctional acrylate crosslinker and an initiator. The method includes curing the UV-curable adhesive reagent by exposing the UV-curable adhesive reagent to a UV light source, thereby fixing the plurality of cell foils to the insulating members in the electrode stack.

[0015] In some embodiments, the polyfunctional acrylate crosslinker includes a multi-indent acrylate alkyl ester.

[0016] In some embodiments, the polyfunctional acrylate crosslinker includes a multi-branched acrylate alkyl ester having N branches, where N is 1, 2, 3, or 4.

[0017] In some embodiments, the polyfunctional acrylate crosslinker includes at least one of ethyl acrylate with a single branch, methyl acrylate with a single branch, diethyl acrylate with two branches, dimethyl acrylate with two branches, triethyl acrylate with three branches, trimethyl acrylate with three branches, tetraethyl acrylate with four branches, and tetramethyl acrylate with four branches.

[0018] In some embodiments, the initiator includes a photoinitiator that includes at least one of peroxides, benzoyl peroxide (BPO), tert-butyl peroxide, azo compounds, azobisisobutyronitrile, phosphine oxides, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoylformate, benzophenone, and thioxanthone.

[0019] In some embodiments, the stacked configuration includes a Z-fold stacked configuration having two or more electrode folds.

[0020] In some embodiments, the UV-curable adhesive reagent includes a polyfunctional acrylate crosslinker and an initiator, and the weight ratio of the initiator to the monomer is from 0.05 wt% to 10 wt%.

[0021] The above features and advantages of the present disclosure, as well as other features and advantages, are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, advantages, and details appear only by way of example in the following detailed embodiments, which reference the accompanying drawings.

[0023] Figure 1 is a vehicle constructed in accordance with one or more embodiments;

[0024] Figure 2 is an exemplary battery stack according to one or more embodiments;

[0025] Figure 3A is an exemplary single-branched ethyl acrylate crosslinker according to one or more embodiments;

[0026] Figure 3B is an exemplary double-branched ethyl acrylate crosslinker according to one or more embodiments;

[0027] Figure 3C is an exemplary triple-branched ethyl acrylate crosslinker according to one or more embodiments;

[0028] Figure 3D is an exemplary four-branched ethyl acrylate crosslinker according to one or more embodiments;

[0029] Figure 4 is an exemplary system for a z-stack battery stack according to one or more embodiments;

[0030] Figure 5A is an example of applying a UV-curable adhesive reagent to a foil support surface of an electrode stack according to one or more embodiments;

[0031] Figure 5B is another example of applying a UV-curable adhesive reagent to a foil support surface of an electrode stack according to one or more embodiments; and

[0032] Figure 6 is a flowchart according to one or more embodiments. Detailed Description

[0033] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0034] Battery manufacturing, such as in the production of soft-packaged lithium-ion batteries, involves the stacking of multiple electrically insulating electrodes. During this stacking process, the goal is to effectively arrange multiple layers of electrode materials, separators, and other components to form a structurally sound and electrically functional stack. In many manufacturing processes, insulating members are located between adjacent battery components to prevent short circuits and ensure proper electrical insulation between the electrodes.

[0035] In one common method, the insulating member takes the form of a continuous sheet of electrically insulating material. This material undergoes a process to create alternating layers, which are then folded and pressed against the battery electrodes, resulting in a so-called "z-fold stack". Alternatively, some systems manipulate the structure to form a "jelly roll stack". In either case, these methods aim to create a compact and well-organized arrangement of battery components within the stack.

[0036] Unfortunately, common manufacturing techniques for electrode stacks result in electrode stacks being prone to misalignment. The folding and pressing mechanisms are sensitive steps, and any failure to secure the fold can cause the electrodes to slide or become misaligned. Misalignment occurs when the electrodes shift within the stack and can result in a loss of battery efficiency.

[0037] The present disclosure introduces a new ultraviolet (UV) curable adhesive reagent for electrode stacks. Instead of relying solely on precise folding of electrodes and insulating sheets, the UV curable adhesive reagent described herein is used to glue the separators to the electrodes during the stacking process. Advantageously, the reagent can be cured by UV light from a liquid phase that is itself compatible with current electrode stack manufacturing processes (e.g., the pre-cured liquid form allows conventional battery cell manufacturing processes without modification). In some embodiments, the UV curable adhesive reagent includes a polyfunctional acrylate crosslinker such as poly-dented alkyl acrylate, an initiator such as benzoyl peroxide (BPO) or benzophenone, and optionally an adhesion additive such as a polymer having an unsaturated structure (e.g., styrene-butadiene (SBR), silicone, etc.) to adjust the curing conditions and increase the adhesion strength.

[0038] According to one or more embodiments, using a UV curable adhesive reagent for electrode stacking provides several technical advantages over existing electrode stack manufacturing processes. In short, battery stacks using a UV curable adhesive reagent as described herein can better withstand rigorous production processes and subsequent transportation without compromising their structural robustness and alignment. In other words, the result is that battery stacks can be produced with a minimal impact on manufacturing speed relative to existing stacking processes, while significantly improving product reliability. Other advantages are possible. For example, the UV curable design allows for faster manufacturing, and the relatively rapid gluing of the separators and electrodes can improve alignment by reducing the time window for sliding. Additionally, the UV curing design itself is a non-contact curing method, preventing contamination of the battery stack. Furthermore, the selection of components of the UV curable adhesive reagent is flexible for different active materials and is compatible with a range of polymer-based separators.

[0039] A vehicle according to an exemplary embodiment is in Figure 1Generally, it is represented by 100 in the context. The vehicle 100 is shown in the form of an automobile having a body 102. The body 102 includes a passenger compartment 104, within which a steering wheel, front row seats, and rear passenger seats (not shown separately) are arranged. A plurality of components are arranged within the body 102, including, for example, an electric motor 106 (shown by the projection under the front hood). The electric motor 106 is shown only for the sake of convenience of illustration and discussion. It should be understood that the construction, position, size, arrangement, etc. of the electric motor 106 are not meant to be particularly limited, and all such constructions (including multi-motor constructions) are within the scope of the present disclosure.

[0040] The electric motor 106 is powered by a battery pack 108 (shown by the projection near the rear of the vehicle 100). The battery pack 108 is shown only for the sake of convenience of illustration and discussion. It should be understood that the construction, position, size, arrangement, etc. of the battery pack 108 are not meant to be particularly limited, and all such constructions (including split constructions) are within the scope of the present disclosure. Additionally, although the present disclosure is mainly discussed in the context of the battery pack 108 for the electric motor 106 configured for the vehicle 100, the aspects described herein can be similarly incorporated within any system (vehicle, building, or other) having an energy storage system (e.g., one or more battery packs or modules), and all such constructions and applications are within the scope of the present disclosure.

[0041] As will be detailed herein, the battery pack 108 includes one or more battery cells and / or battery pouches made of an electrode stack fixed by an ultraviolet curable adhesive reagent. Figure 2 An exemplary electrode stack adhered by an ultraviolet curable adhesive reagent is shown in. Exemplary compounds for the ultraviolet curable adhesive reagent are shown in Figure 3A 、 3B 、3C and 3D. Figure 4 An exemplary manufacturing process of stacking electrodes using an ultraviolet curable adhesive reagent is shown in. An example battery foil support surface including a certain amount of the ultraviolet curable adhesive reagent is shown in Figure 5A and 5B is shown.

[0042] Figure 2 An exemplary battery stack 200 according to one or more embodiments is shown. The battery stack 200 can be incorporated as a component of multiple battery cells in a battery pack (e.g., Figure 1 the battery pack 108 in). As Figure 2As shown, the battery stack 200 includes a plurality of battery foils 202, and the plurality of battery foils 202 are separated via an insulating member 204 in a so-called z-fold stacked configuration having a plurality of electrode folds 206 (also referred to as electrode layers, or foil layers or folds). It should be understood that although the z-fold stacked configuration is shown for convenience, other stacking arrangements are possible, and all such configurations are within the scope of the present disclosure. Additionally, although Figure 2 the specific z-fold stacked configuration shown in depicts two folds 206, it should be understood that the folding process can continue to produce a battery stack 200 having any number of folds 206.

[0043] As Figure 2 further shown, the plurality of battery foils 202 are fixed to the insulating member 204 using an ultraviolet (UV)-curable adhesive reagent 208 (shown by projection). In some embodiments, the UV-curable adhesive reagent 208 is cured to adhesively bond the battery foils 202 to the insulating member 204 using a UV light source (see Figure 5A and 5B ). The UV-curable adhesive reagent 208 is discussed in more detail with respect to Figures 3A to 3D .

[0044] The battery foils 202 can be made of a conductive metal sheet or foil. For example, the cathode battery foil can be made of aluminum foil, stainless steel, and / or titanium foil. Other materials are possible, such as semimetals (e.g., tin, graphite) and alloys of metals and / or their semimetals. The anode battery foil is typically made of copper and / or copper foil, but other materials, such as copper alloys, stainless steel, carbon foil, silicon foil, and silicon alloy foil, are also possible. The insulating member 204 can include a dielectric material, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and their composites, but other dielectrics are also within the scope of the present disclosure. Although not shown separately, in some embodiments, an active material is applied to the battery stack 200. The active material is not particularly limited and can include, for example, various cathode or anode materials (depending on the requirements of the specific application), such as activated carbon powder, nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), nickel cobalt aluminum oxide (NCA), nickel cobalt manganese aluminum oxide (NCMA), lithium manganese iron phosphate (LMFP), lithium-rich manganese (LMR), lithium manganese oxide (LMO), graphite, silicon, silicon-graphite composite, tin, tin oxide (SnO2), lithium titanate (Li4Ti5O12, LTO), sulfur, and lithium-sulfur (Li-S) composite, lithium metal (Li), and / or lithium alloys, such as lithium-antimony (Li-Sb), lithium-aluminum (Li-Al), and lithium-germanium (Li-Ge).

[0045] Figure 3A 、 Figure 3B 、Figure 3C and Figure 3D illustrates an example of an ultraviolet (UV) curable adhesive reagent 208 in accordance with one or more embodiments. In some embodiments, the UV curable adhesive reagent 208 includes a polyfunctional acrylate crosslinker, such as a multi-indent acrylate alkyl ester. As used herein, a "multi-indent" acrylate alkyl ester refers to a multi-branched acrylate alkyl ester having N branches. Figure 3A depicts a UV curable adhesive reagent 208 having a single-branched (e.g., N = 1) ethyl acrylate crosslinker. Although a single-chain ethyl acrylate is shown for convenience, a single-chain methyl acrylate (and other acrylate alkyl esters) having only a single carbon between the oxygen and the end group "R" is also possible and within the scope of this disclosure. Figure 3B depicts a UV curable adhesive reagent 208 having a double-branched (e.g., N = 2) diethyl acrylate crosslinker. Similarly, other double-branched acrylate alkyl esters are possible and within the scope of this disclosure. Figure 3C depicts a UV curable adhesive reagent 208 having a triple-branched (e.g., N = 3) triethyl acrylate crosslinker. Similarly, other triple-branched acrylate alkyl esters are possible and within the scope of this disclosure. Figure 3D depicts a UV curable adhesive reagent 208 having a quadruple-branched (e.g., N = 4) tetraethyl acrylate crosslinker. Similarly, other quadruple-branched acrylate alkyl esters are possible and within the scope of this disclosure.

[0046] In Figure 3A , 3B , 3C, and 3D, in each configuration shown, the end group R can include a series of polymers and / or hydrocarbon chains. For example, the end group R can include methyl, ethyl (see Figure 3A ), an N-length hydrocarbon chain (e.g., a 6-carbon chain in a diacrylate hexanediol diacrylate configuration, etc.), triethyl (e.g., for a trimethylolpropane triacrylate configuration, etc.), tetraethyl (e.g., for a pentaerythritol tetraacrylate, etc.). Other acrylate units / crosslinkers and multi-branched units / crosslinkers are possible, and all such configurations are within the scope of this disclosure.

[0047] In some embodiments, the ultraviolet (UV) curable adhesive reagent 208 comprises a mixture of a multifunctional acrylate crosslinker and an initiator (not shown separately). In some embodiments, the initiator is a photoinitiator to support UV curing of the UV curable adhesive reagent 208. The initiator can be selected from various type 1 and type 2 categories. As used herein, a "type 1" initiator refers to an initiator that generates primary free radicals by splitting upon photon absorption. As used herein, a "type 2" initiator refers to an initiator that absorbs photons and then uses hydrogen from a chemical or co-initiator to prepare secondary free radicals. Type 1 initiators include, for example, peroxides such as benzoyl peroxide (BPO) and tert-butyl peroxide, azo compounds such as azobisisobutyronitrile, phosphine oxides such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide, and methyl benzoylformate. Type 2 initiators include, for example, benzophenone and thioxanthone. In some embodiments, the initiator is mixed with the monomer (multifunctional acrylate crosslinker) at an initiator-to-monomer weight ratio of 0.05 wt% to 10 wt%. In some embodiments, the UV curable adhesive reagent 208 includes optional adhesion additives, such as polymers having an unsaturated structure, to adjust the curing conditions and increase the adhesive strength. Exemplary adhesion additives include styrene butadiene (SBR) and silicone.

[0048] In some embodiments, after mixing the multifunctional acrylate crosslinker, initiator, and optional adhesion additives, the resulting UV curable adhesive reagent 208 is applied to the separator and / or foil surface for the electrode stack (see Figure 5A and 5B ). The UV curable adhesive reagent 208 can be applied using any suitable process, such as by syringe, reverse comb, etc. In some embodiments, the UV curable adhesive reagent 208 is then cured by UV irradiation using, for example, a UV source / box / spotlight, UV laser, etc. The curing can be performed after each folding step (i.e., after adding each new foil and the corresponding portion of the insulating member) and / or after completing the corresponding electrode stack.

[0049] Figure 4 An example system 400 for a z-stack battery stack (e.g., battery stack 200) according to one or more embodiments is shown. As Figure 4 shown, the system 400 includes a stack table 402 and a z-fold arm 404 having an electrically insulating material feed system 406. In some embodiments, the z-fold arm 404 places a quantity of insulating member 204 (which itself is made of an electrically insulating material as described previously) onto the stack table 402 to form as Figure 2The battery stack 200 shown. In some embodiments, the z-folded arm 404 includes an ultraviolet light protection device 408, and the ultraviolet light protection device 408 includes a first protection member 410 and a second protection member 412. The first protection member 410 and the second protection member 412 shield the insulating member 204 from unintentional (premature) exposure to UV light.

[0050] In some embodiments, the z-folded arm 404 includes a terminal 414 having a pair of guide rollers 416. The guide rollers 416 move a portion of the insulating member 204 back and forth on the stacking table 402 to form the battery stack 200. In some embodiments, the guide rollers 416 pass a predetermined portion (length) of the insulating member 204 over a selectively displaceable folding guide 418 to create a series of electrode folds 206.

[0051] In some embodiments, each of the series of electrode folds 206 is z-shaped, thereby creating a foil support surface 420 on which the battery foil 202 is positioned. Thus, multiple battery foils 202 and multiple battery support surfaces 420 form a consolidated battery stack 200 such as Figure 2 shown. At this point, it should be reiterated again that the series of folds shown are merely illustrative, and other geometries may be employed.

[0052] Now reference will be made to Figure 5A and continuing reference will be made to Figure 4 In a non-limiting example, one of the multiple foil support surfaces 420 will be described. The foil support surface 420 includes a first dimension D1 that defines a first axis and a second dimension D2 that defines a second axis that is substantially perpendicular to the first axis. In a non-limiting example, the first dimension D1 is less than the second dimension D2.

[0053] In some embodiments, the foil support surface 420 includes a folded edge 502 that extends along the second axis and a pre-folded edge 504 that extends along the second axis. As used herein, the term "folded edge" describes an edge that has been folded over the folding guide 418, and the term "pre-folded edge" describes an edge that has not been folded. As Figure 5A shown, the dimension D2 is defined between a first end 506 and a second end 508 of the foil support surface 420.

[0054] In some embodiments, a UV-based curing system shown in the form of a UV lamp 510 is mounted relative to the stacking table 402 along the first axis. In some embodiments, a quantity of ultraviolet curable adhesive reagent 208 is applied to the foil support surface 420. In some embodiments, a quantity of ultraviolet curable adhesive reagent 208 is applied along the first axis at the first end 506 and the second end 508. Once applied, the z-folded arm 404 (see Figure 4)Shift to position a new layer of electrically insulating material (the next layer of the insulating member 204) above the battery foil 202, thereby creating a new foil support surface 420. At this time, the UV lamp 510 can be illuminated to activate the portion of the ultraviolet curable adhesive reagent 208 applied to the corresponding foil support surface 420. In this way, the battery stack 200 includes multiple bonding layers, which are more stable and less prone to displacement during storage or transportation.

[0055] Reference will now be made to Figure 5B , and continuing reference will be made to Figure 4 , one of the multiple foil support surfaces 420 is described in another non-limiting example. In some embodiments, the UV-based curing system shown in the form of the UV lamp 510 is mounted relative to the stacking table 402 along a second axis. In some embodiments, an amount of ultraviolet curable adhesive reagent 208 is applied to the foil support surface 420. In some embodiments, an amount of ultraviolet curable adhesive reagent 208 is applied across the second axis to the pre-folded edge 504. In some embodiments, additional ultraviolet curable adhesive reagent 208 can also (or alternatively) be applied along the second axis to the folded edge 502. In a manner similar to that previously discussed herein, the UV lamp 510 can be selectively activated to cure an amount of ultraviolet curable adhesive reagent 208 applied across the second axis to the pre-folded edge 504 and / or the folded edge 502 to bond a series of electrode folds 206 to produce a consolidated battery stack 200 (see Figure 2 ).

[0056] Now refer to Figure 6 , and a flowchart 600 for electrode stacking using an ultraviolet curable adhesive reagent is generally shown according to an embodiment. Refer to Figures 1 - 5B for a description of the flowchart 600, and the flowchart 600 may include Figure 6 additional steps not depicted therein. Although depicted in a specific order, the blocks depicted in Figure 6 can be rearranged, subdivided, and / or combined.

[0057] At block 602, the method includes forming an electrode stack having a plurality of battery foils separated by insulating members, the plurality of battery foils being in a stacked configuration, the stacked configuration including alternating battery foils and insulating member layers.

[0058] In some embodiments, the stacked configuration includes a z-fold stacked configuration having two or more electrode folds.

[0059] At block 604, the method includes applying an ultraviolet curable adhesive reagent between the alternating battery foils and insulating member layers. The ultraviolet curable adhesive reagent includes a polyfunctional acrylate crosslinking agent and an initiator.

[0060] In some embodiments, the multifunctional acrylate crosslinker includes a multi-dented alkyl acrylate. In some embodiments, the multifunctional acrylate crosslinker includes a multi-branched alkyl acrylate having N branches, where N is 1, 2, 3, or 4. In some embodiments, the multifunctional acrylate crosslinker includes at least one of ethyl acrylate with a single branch, methyl acrylate with a single branch, diethyl acrylate with two branches, dimethyl acrylate with two branches, triethyl acrylate with three branches, trimethyl acrylate with three branches, tetraethyl acrylate with four branches, and tetramethyl acrylate with four branches.

[0061] In some embodiments, the ultraviolet curable adhesive reagent includes a multifunctional acrylate crosslinker and an initiator, and the weight ratio of the initiator to the monomer is from 0.05 wt% to 10 wt%.

[0062] In some embodiments, the initiator includes a photoinitiator, and the photoinitiator includes at least one of peroxides, benzoyl peroxide (BPO), tert-butyl peroxide, azo compounds, azobisisobutyronitrile, phosphine oxides, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoylformate, benzophenone, and thioxanthone.

[0063] At block 606, the method includes curing the ultraviolet curable adhesive reagent by exposing the ultraviolet curable adhesive reagent to an ultraviolet light source, thereby fixing a plurality of battery foils to an insulating member in an electrode stack.

[0064] The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Unless the context clearly dictates otherwise, the term "or" means "and / or". References to "aspect" throughout the specification mean that a particular element (e.g., a feature, a structure, a step, or a property) described in connection with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. Additionally, it should be understood that the described elements can be combined in any suitable manner in the various aspects.

[0065] When an element such as a layer, a film, a region, or a substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, no intervening elements are present.

[0066] Unless otherwise stated herein, all test standards are the latest standards in effect as of the filing date of this application, or if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0067] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0068] Although the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and elements thereof can be replaced with equivalents without departing from its scope. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from its basic scope. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A vehicle, comprising: an electric motor; and a battery pack electrically connected to the electric motor, the battery pack including a plurality of battery cells, each battery cell including an electrode stack; wherein the electrode stack of each battery cell includes a plurality of battery foils separated by insulating members in a stacked configuration, the stacked configuration including alternating layers of battery foils and insulating members; wherein the electrode stack of each battery cell further includes an ultraviolet curable adhesive reagent applied between the alternating layers of battery foils and insulating members to bond the plurality of battery foils to the insulating members; and wherein the ultraviolet curable adhesive reagent includes a polyfunctional acrylate crosslinking agent and an initiator.

2. The vehicle according to claim 1, wherein the polyfunctional acrylate crosslinking agent includes a multi-dented acrylic alkyl ester.

3. The vehicle according to claim 1, wherein the polyfunctional acrylate crosslinking agent includes a multi-branched acrylic alkyl ester having N branches, where N is 1, 2, 3, or 4.

4. The vehicle according to claim 3, wherein the polyfunctional acrylate crosslinking agent includes at least one of mono-branched ethyl acrylate, mono-branched methyl acrylate, di-branched diethyl acrylate, di-branched dimethyl acrylate, tri-branched triethyl acrylate, tri-branched trimethyl acrylate, tetra-branched tetraethyl acrylate, and tetra-branched tetramethyl acrylate.

5. The vehicle according to claim 1, wherein the initiator includes a photoinitiator, the photoinitiator including at least one of peroxides, benzoyl peroxide (BPO), tert-butyl peroxide, azo compounds, azobisisobutyronitrile, phosphine oxides, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoylformate, benzophenone, and thioxanthone.

6. The vehicle according to claim 1, wherein the stacked configuration includes a Z-shaped folded stacked configuration having two or more electrode folds.

7. The vehicle according to claim 1, wherein the ultraviolet curable adhesive reagent is cured using an ultraviolet light source to fix the electrode stack.

8. An ultraviolet curable adhesive reagent, comprising: a polyfunctional acrylate crosslinking agent including a multi-dented acrylic alkyl ester including a multi-branched acrylic alkyl ester having N branches, where N is 1, 2, 3, or 4; and an initiator having an initiator-to-monomer weight ratio of 0.05 wt% to 10 wt%.

9. The ultraviolet curable adhesive reagent according to claim 8, wherein the polyfunctional acrylate crosslinking agent includes at least one of mono-branched ethyl acrylate, mono-branched methyl acrylate, di-branched diethyl acrylate, di-branched dimethyl acrylate, tri-branched triethyl acrylate, tri-branched trimethyl acrylate, tetra-branched tetraethyl acrylate, and tetra-branched tetramethyl acrylate.

10. The ultraviolet curable pressure-sensitive adhesive reagent according to claim 8, wherein the initiator comprises a photoinitiator, and the photoinitiator comprises at least one of peroxide, benzoyl peroxide (BPO), tert-butyl peroxide, azo compound, azobisisobutyronitrile, phosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoylformate, benzophenone and thioxanthone.

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