Battery case, battery pack, and method of manufacturing battery pack

Abstract

Disclosed herein are a battery case, a battery pack, and a method of manufacturing the battery pack. The battery case is configured to accommodate a plurality of battery cells, and includes a first case and a second case bonded to the first case at a bonding region by laser bonding. The first housing has a convex semicircular cross-sectional shape in the joining region.

Description

Technical Field

[0001] This disclosure relates to a battery casing, a battery pack, and a method of manufacturing a battery pack, and more specifically, to a battery casing, a battery pack, and a method of manufacturing a battery pack in which a joint region is uniformly and stably formed between a first casing and a second casing. Background Technology

[0002] Unlike primary batteries, which are not designed for recharging, secondary batteries can be discharged and recharged. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders. High-capacity secondary batteries are widely used as power sources for driving motors (such as in hybrid or electric vehicles) and for energy storage. A secondary battery includes an electrode assembly containing positive and negative electrodes, a housing that houses the electrode assembly, and terminal portions that connect to the electrode assembly.

[0003] For battery packs comprising multiple secondary batteries, the individual cells are housed within a casing made of a plastic-like material to protect them from external impacts and environmental factors. The large-area casing consists of two upper and lower casings, which are joined at their interface using heat generated by a laser, thus sealing the casing. However, if the joint length is long, a height difference may occur between the start and end points of the joint area. Furthermore, the casing material may deform when the temperature approaches its melting point.

[0004] The information disclosed in this background section is intended to enhance understanding of the background of this disclosure, and may include information that does not constitute related technology or prior art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a battery housing, a battery pack, and a method for manufacturing a battery pack, wherein a bonding surface is uniformly and stably formed between a first housing and a second housing joined by laser bonding.

[0006] However, the technical problems to be solved by this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the following description of this disclosure other problems not mentioned herein, as well as aspects and features of this disclosure that will solve these problems.

[0007] According to one aspect of the present disclosure, a battery housing configured to accommodate a plurality of battery cells is provided, and the battery housing includes a first housing and a second housing connected to the first housing at a joining region by laser bonding, wherein the first housing has a convex semi-circular cross-sectional shape in the joining region.

[0008] The second housing has a concave semi-circular cross-sectional shape in the joint area that corresponds to the convex semi-circular cross-sectional shape of the first housing.

[0009] The first housing can be made of a material through which laser light can pass.

[0010] The second housing includes a receiving groove adjacent to the engagement area.

[0011] A thermosetting resin, including a photoinitiator, is disposed in the bonding area.

[0012] Above the joint area, an ultraviolet blocking coating is applied to the upper outer surface of the first housing.

[0013] The UV-blocking coating can have a predetermined color.

[0014] According to another aspect of this disclosure, a battery pack is provided, the battery pack including a plurality of battery cells and a battery housing configured to accommodate the plurality of battery cells, wherein the battery housing includes a first housing and a second housing joined to the first housing at a joining region by laser bonding, and the first housing having a convex semi-circular cross-sectional shape in the joining region.

[0015] The second housing may have a concave semi-circular cross-sectional shape in the joint area that corresponds to the convex semi-circular cross-sectional shape of the first housing.

[0016] The first housing can be made of a material through which laser light can pass.

[0017] The second housing includes a receiving groove formed adjacent to the mating area.

[0018] A thermosetting resin, including a photoinitiator, is disposed in the bonding area.

[0019] Above the joint area, an ultraviolet blocking coating is applied to the upper outer surface of the first housing.

[0020] The UV-blocking coating can have a predetermined color.

[0021] According to another aspect of this disclosure, a method for manufacturing a battery pack is provided, the method comprising manufacturing a first housing, manufacturing a second housing, accommodating a plurality of battery cells in the second housing, and joining the first housing and the second housing at a joining region by laser bonding, wherein the first housing has a convex semi-circular cross-sectional shape in the joining region.

[0022] The second housing has a concave semi-circular cross-sectional shape in the joint area that corresponds to the convex semi-circular cross-sectional shape of the first housing.

[0023] The first housing can be made of a material through which laser light can pass.

[0024] The receiving groove can be provided in the second housing adjacent to the engagement area.

[0025] A thermosetting resin, including a photoinitiator, is disposed in the bonding area.

[0026] The method may also include applying an ultraviolet-blocking coating to the upper outer surface of the first housing above the joint area.

[0027] However, the aspects and features of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the following detailed description other aspects and features not mentioned. Attached Figure Description

[0028] The accompanying drawings illustrate preferred embodiments of the present disclosure and are used to further describe aspects and features of the present disclosure together with its detailed description. This disclosure should not be construed as being limited to the drawings. Figure 1 This is a schematic diagram of a cylindrical lithium secondary battery according to an embodiment; Figure 2 This is a schematic diagram of a prismatic lithium secondary battery according to an embodiment; Figure 3 and Figure 4 This is a schematic diagram of a pouch-type lithium secondary battery according to an embodiment; Figures 5A to 5C This is a view of a traditional battery casing; Figures 6A to 6C This is a cross-sectional view of the mating surface of the battery casing according to a first embodiment of the present disclosure; Figure 7A and Figure 7B This is a cross-sectional view of the mating surface of the battery casing according to a second embodiment of the present disclosure; Figure 8 This is a cross-sectional view of the mating surface of the battery casing according to a third embodiment of the present disclosure; and Figure 9 This is a flowchart of a method for manufacturing a battery pack according to an embodiment of the present disclosure. Detailed Implementation

[0029] Exemplary embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Before description, it should be noted that the terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, but rather should be understood to have meanings and concepts consistent with the spirit of this disclosure, based on the principle that the inventor can appropriately define the concept of each term in order to describe his / her own invention in the best possible way. Therefore, since the embodiments described in this specification and the constructions shown in the drawings are merely examples of this disclosure and do not cover all the technical ideas of this disclosure, various changes and modifications can be made upon filing this application.

[0030] It will also be understood that when the terms “include / contain” and / or variations thereof are used herein, it indicates the presence of the stated features, integers (whole), steps, operations, elements, components and / or groups thereof, but does not preclude the presence or addition of one or more other features, integers (whole), steps, operations, elements, components and / or groups thereof.

[0031] For ease of understanding of this disclosure, the drawings are not drawn to scale, and the dimensions of some components may be exaggerated. It should be noted that the same reference numerals designate the same components in different embodiments.

[0032] Referring to two compared elements, features, etc., as “identical” means that they are “substantially identical.” Therefore, the phrase “substantially identical” can include what is considered a low deviation in the art, for example, 5% or less. The uniformity of any parameter in a given region can mean that it is uniform from an average perspective.

[0033] Although terms such as "first" and / or "second" are used to describe different components, these components are of course not limited by these terms. These terms are only used to distinguish one component from another. Therefore, unless specifically stated to the contrary, the first component may be referred to as the second component without departing from the teachings of the exemplary embodiments.

[0034] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0035] Arranging any component "above (or below)" or "on (or under)" a component can mean that any component is positioned to contact the upper (or lower) surface of that component, or that other components can be positioned between that component and any component above (or below) that component.

[0036] It will be understood that when a component is referred to as “connected,” “joined,” or “engaged” to another component, it can be directly “connected,” “joined,” or “engaged” to said other component, and it can also be indirectly “connected,” “joined,” or “engaged” to said other component, with other elements placed between them.

[0037] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. When describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” Expressions such as “at least one” and “one or more” modify the entire list of elements when preceding it, without modifying individual elements within that list.

[0038] Throughout the specification, when “A and / or B” is stated, it means A, B, or A and B, unless otherwise stated. Similarly, when “C to D” is stated, it means C or greater and D or less, unless specifically stated otherwise.

[0039] When phrases such as “at least one of A, B and C (species / beings)”, “at least one of A, B or C (species / beings)”, “at least one of the group selected from A, B and C (species / beings)” or “at least one of A, B and C (species / beings)” are used to specify a list of elements A, B and C, the phrase can refer to any suitable combination and all suitable combinations.

[0040] The term “use” may be considered synonymous with the term “utilize”. As used herein, the terms “substantially,” “about,” and similar terms are used as approximations rather than terms of degree and are intended to account for inherent biases in measurements or calculations that would be recognized by one of ordinary skill in the art.

[0041] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the teachings of the exemplary embodiments, the first element, first component, first region, first layer, or first portion discussed below may be referred to as a second element, second component, second region, second layer, or second portion.

[0042] For ease of explanation, when describing the relationship between one element or feature as shown in the accompanying drawings and another element or feature(s), spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used herein. It will be understood that, in addition to the orientation depicted in the drawings, spatial relative positions are intended to also encompass different orientations of the device in use or operation. For example, if the device in the drawings is flipped, any element described as “below” or “under” another element may subsequently be oriented “above” or “on” another element. Thus, the term “below” can encompass both upward and downward directions.

[0043] The secondary battery can be coin-shaped, cylindrical, prismatic, or pouch-shaped. Because this disclosure is applicable to these types of secondary batteries, cylindrical secondary batteries, pouch-shaped secondary batteries, and prismatic secondary batteries are described before describing embodiments of this disclosure.

[0044] Figures 1 to 4 This is a schematic diagram of a lithium secondary battery according to an example of this disclosure. Figure 1 A cylindrical lithium secondary battery is shown. Figure 2 A prismatic secondary battery is shown. Figure 3 and Figure 4 A pouch-type secondary battery is shown. (See reference...) Figures 1 to 4 A lithium secondary battery may include an electrode assembly 40, with a separator 30 positioned between a first electrode plate 10 and a second electrode plate 20. The electrode assembly 40 is housed within a housing 50. The first electrode plate 10, the second electrode plate 20, and the separator 30 may be impregnated with an electrolyte (not shown). Figure 1 As shown, the lithium secondary battery may include a sealing member 60 of a sealed housing 50. Figure 2 In this lithium secondary battery, a first electrode lead connector 11, a first electrode terminal 12, a second electrode lead connector 21, and a second electrode terminal 22 are included. For example... Figure 3 and Figure 4 As shown, the lithium secondary battery includes electrode terminals 70, namely a first electrode terminal 71 and a second electrode terminal 72, which provide electrical channels for inducing current formed in the electrode assembly 40 to the outside of the electrode assembly 40.

[0045] The electrode assembly 40 can be formed by winding or stacking the first electrode plate 10, the second electrode plate 20, and the diaphragm 30, each of which is formed in a plate shape or a film shape. For winding and stacking, the winding axis of the electrode assembly 40 can be parallel to the length direction of the housing. In other examples, the electrode assembly 40 can be stacked, but the shape of the electrode assembly 40 is not limited in this disclosure. The first electrode plate 10 of the electrode assembly 40 can be used as a positive electrode, and the second electrode plate 20 can be used as a negative electrode, and vice versa.

[0046] The first electrode plate 10 can be formed by depositing a first electrode active material (such as graphite or carbon) onto a first electrode current collector formed of a metal foil (such as copper, copper alloy, nickel, or nickel alloy). The first electrode plate 10 may include a first electrode tab (or a first uncoated portion) as a region where the first electrode active material is not disposed.

[0047] The second electrode plate 20 can be formed by depositing a second electrode active material (such as a transition metal oxide) onto a second electrode current collector formed of a metal foil (such as aluminum or an aluminum alloy). The second electrode plate 20 may include a second electrode tab (or a second uncoated portion) as a region where no second electrode active material is disposed.

[0048] The separator 30 can be used to allow lithium ions to move between the electrode plates 10 and 20 while preventing short circuits between the first electrode plate 10 and the second electrode plate 20. The separator 30 can be, for example, a polyethylene membrane, a polypropylene membrane, or a polyethylene-polypropylene membrane.

[0049] The described secondary battery can be configured as multiple secondary batteries to form multiple battery cells that can be housed in a battery casing to form a battery pack.

[0050] Figures 5A to 5C This is a view of a traditional battery casing.

[0051] Reference Figures 5A to 5C The battery casing may include, for example, Figure 5A The diagram shows a first housing 1 and a second housing 2. To join the battery housings, a groove is formed on the first housing 1 and a protrusion is formed on the second housing 2 in the joining region. When the first housing 1 is positioned on the second housing 2, the first housing 1 and the second housing 2 are joined at the joining region by heat generated by a laser.

[0052] The process of forming the joint area between the first housing 1 and the second housing 2 will be described in detail. For example... Figure 5B As shown, the first housing 1 and the second housing 2 are joined by melting the upper part A of the protrusion formed on the second housing 2 using a laser. The molten substrate is accommodated in receiving portions B located on the left and right sides of the groove formed in the first housing 1.

[0053] like Figure 5C As shown, when a laser is irradiated from above the first housing 1, heat is distributed on the joint surface between the first housing 1 and the second housing 2 (as shown in "C"), causing the molten substrate to move to the receiving portion (as shown in "D") to form a joint between the first housing 1 and the second housing 2. If the first housing 1 and the second housing 2 are made of plastics from the same material family, such as polycarbonate (PC), the material may deform near its melting point upon laser incidence. This deformation of the material may affect the strength or sealing force of the joint between the first housing 1 and the second housing 2.

[0054] Figures 6A to 6C This is a cross-sectional view showing the joint area of ​​the battery casing according to a first embodiment of the present disclosure.

[0055] Reference Figures 6A to 6C According to a first embodiment of the present disclosure, the battery housing may include a first housing 110 and a second housing 120, wherein the second housing 120 is joined to the first housing 110 at a joining region by laser bonding. Since the first housing 110 and the second housing 120 have the same structure as the conventional first housing and second housing described above, except for the joining portion between the housings 110 and 120, detailed illustrations and descriptions of the housings 110 and 120 will be omitted.

[0056] The first housing 110 may have a convex semi-circular cross-section 111 at the joint area between the first housing 110 and the second housing 120. Additionally, the second housing 120 may have a concave semi-circular cross-section 121 at the joint area between the first housing 110 and the second housing 120, corresponding to the convex semi-circular cross-section of the first housing 110. Here, the first housing 110 may be made of a material capable of generating heat to join the housings 110 and 120 using a laser. For example, the first housing 110 may be made of polycarbonate (PC). Figure 6B As shown, since the cross-section of the first housing 110 is a convex semi-circle and the cross-section of the second housing 120 is a corresponding concave semi-circle, the joint area between the first housing 110 and the second housing 120 corresponds to the shape of the heat distribution E generated by the laser. Therefore, the battery housing 100 according to the embodiments of this disclosure can be configured to uniformly disperse the heat of the laser onto the joint surfaces of the first housing 110 and the second housing 120, thereby uniformly and stably forming a joint area between the first housing 110 and the second housing 120. Furthermore, deformation of the housing material near the melting point caused by the heat generated by the laser can be prevented.

[0057] In an embodiment, the second housing 120 may have a receiving groove 122 formed adjacent to the joint area between the first housing 110 and the second housing 120. Molten substrate, melted by the heat of the laser, moves into and is accommodated in the receiving groove 122, as indicated by "F". Thus, as... Figure 6C As shown, a stable joint is formed between the first housing 110 and the second housing 120.

[0058] Figure 7A and Figure 7B This is a cross-sectional view of the joint area of ​​the battery casing according to a second embodiment of the present disclosure.

[0059] Reference Figure 7A In addition to the above references Figures 6A to 6C In addition to the described construction, the battery housing according to the second embodiment of this disclosure can also be configured such that a thermosetting resin 130 including a photoinitiator is applied to the second housing 120 at the joint region between the first housing 110 and the second housing 120. When a laser is directed to the joint region, the laser heats the joint region between the first housing 110 and the second housing 120. Meanwhile, as Figure 7B As shown, the photoinitiator in the thermosetting resin 130 can be activated by the wavelength of a laser, thereby rapidly forming a stable bond.

[0060] Figure 8 This is a cross-sectional view of the joint area of ​​the battery casing according to a third embodiment of the present disclosure.

[0061] Reference Figure 8In addition to the above references, the battery casing according to the third embodiment of this disclosure... Figures 6A to 6C In addition to the described construction, an ultraviolet-blocking coating 140 may be included on the upper outer surface of the first housing 110 above the joint area between the first housing 110 and the second housing 120. This blocks specific wavelengths of energy sources that could cause a reaction within the battery housing, thus suppressing deformation of the battery housing. The ultraviolet-blocking coating 140 may, for example, allow only visible light to pass through to the first housing 110 after the first housing 110 and the second housing 120 are joined at the joint area by laser.

[0062] In an embodiment, the UV-blocking coating 140 may have a predetermined color. For example, the UV-blocking coating 140 may have a color that provides good visibility through it. Therefore, for a battery housing according to an embodiment of the present disclosure, the damaged area is easily located because the UV-blocking coating 140 applied to the upper outer surface of the first housing 110 visually identifies coating cracks caused by deformation of the battery housing 100.

[0063] Figure 9 This is a flowchart of a method for manufacturing a battery pack according to an embodiment of the present disclosure. The method for manufacturing a battery pack according to an embodiment of the present disclosure may include steps S210 to S240.

[0064] In step S210, a first housing is manufactured. In an embodiment, the first housing includes a convex semi-circular cross-section at the junction region between the first housing and the second housing. The first housing may be made of a material through which laser light can pass.

[0065] In step S220, a second housing is manufactured and attached to the first housing. The second housing may include a concave semi-circular cross-sectional shape corresponding to the convex semi-circular cross-sectional shape of the first housing at the joint area between the first and second housings. Additionally, step S220 may include forming a receiving groove adjacent to the joint area between the first and second housings.

[0066] After step S220, the method of manufacturing the battery pack may further include the step of applying a thermosetting resin including a photoinitiator to the second housing in the joint area between the first housing and the second housing.

[0067] In step S230, multiple battery cells are housed in the second housing.

[0068] In step S240, the first housing and the second housing are joined at the joining area by laser bonding.

[0069] After step S240, the method may further include the step of applying an ultraviolet blocking coating to the upper outer surface of the first housing above the joint area between the first housing and the second housing.

[0070] The above has been referenced Figure 9 The flowcharts in the document illustrate a method for manufacturing a battery pack according to embodiments of the present disclosure. For simplicity, the method has been shown and described as a series of blocks, but the present disclosure is not limited to the order of the blocks. Furthermore, some blocks may occur in a different order or simultaneously with other blocks, and various different branches, processes, and block sequences may be implemented to achieve the same or similar results. Moreover, it may not be necessary to implement the method using all the blocks shown.

[0071] In reference Figure 9 In the description, according to embodiments of this disclosure, each step can be further divided into additional steps or combined into fewer steps. Additionally, if necessary, some steps can be omitted or the order of the steps can be changed. Furthermore, Figures 1 to 8 The content can be applied to Figure 9 The content. On the other hand... Figure 9 The content can be applied to Figures 1 to 8 The content.

[0072] Materials that can be used in secondary batteries according to embodiments of this disclosure are described below.

[0073] Compounds capable of reversibly inserting and deintercalating lithium (e.g., lithiation intercalation compounds) can be used as positive electrode active materials. Specifically, a composite oxide of lithium and one or more metals selected from cobalt, manganese, nickel, and combinations thereof can be used as the positive electrode active material. The composite oxide can be a lithium transition metal composite oxide. Examples of composite oxides include lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free lithium nickel manganese oxides, or combinations thereof. Compounds represented by one of the following chemical formulas can be used: Li a A 1-b X b O 2- c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b- c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4 (0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3 (0≤f≤2); and Li a FePO4 (0.90≤a≤1.8). In these chemical formulas, A can be Ni, Co, Mn, or a combination thereof; X can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D can be O, F, S, P, or a combination thereof; G can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L 1 It can be Mn, Al, or a combination thereof.

[0074] The positive electrode for a lithium secondary battery may include a current collector and a layer of positive electrode active material formed on the current collector. The positive electrode active material layer may include a positive electrode active material, and may also include a binder and / or a conductive material.

[0075] With respect to 100 wt% of the positive electrode active material layer, the amount of the positive electrode active material can be 90 wt% to 99.5 wt%. With respect to 100 wt% of the positive electrode active material layer, the amounts of the binder and the conductive material can be 0.5 wt% to 5 wt%.

[0076] Aluminum can be used as the current collector. However, the present disclosure is not limited thereto.

[0077] The negative electrode active material can include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, a lithium metal alloy, a material capable of doping and dedoping with respect to lithium, or a transition metal oxide.

[0078] The material capable of reversibly intercalating / deintercalating lithium ions can include a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon are graphite, such as natural graphite or synthetic graphite. Examples of amorphous carbon can include soft carbon, hard carbon, mesophase pitch carbide, and coke.

[0079] A Si-based negative electrode active material or a Sn-based negative electrode active material can be used as the material capable of doping and dedoping with respect to lithium. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiO x (0 < x < 2), a Si-based alloy, or a combination thereof.

[0080] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to an example, the silicon-carbon composite includes silicon particles and can have a form in which amorphous carbon is coated on the surface of the silicon particles.

[0081] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous carbon coating provided on the surface of the core.

[0082] The negative electrode for a lithium secondary battery can include a current collector and a negative electrode active material layer provided on the current collector. The negative electrode active material layer can include a negative electrode active material and can further include a binder and / or a conductive material.

[0083] For example, the negative electrode active material layer can include 90 wt% to 99 wt% of the negative electrode active material, 0.5 wt% to 5 wt% of the binder, and 0 wt% to 5 wt% of the conductive material.

[0084] A non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof can be used as the binder. If an aqueous binder is used as the binder for the negative electrode, the binder for the negative electrode can further include a cellulose-based compound capable of dispensing viscosity.

[0085] Nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, polymer matrix coated with conductive metal, and combinations thereof can be used as current collectors for negative electrodes.

[0086] Electrolytes used in lithium-ion secondary batteries may include non-aqueous organic solvents and lithium salts. Non-aqueous organic solvents serve as the medium through which ions participating in the electrochemical reactions of the battery move. These solvents can be carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents, or combinations thereof. Carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, or aprotic solvents can be used alone, or two or more of them can be mixed and used as non-aqueous organic solvents. If carbonate solvents are used, cyclic carbonates and chain carbonates can be mixed and used.

[0087] Depending on the type of lithium-ion secondary battery, a separator can be placed between the positive and negative electrodes. Polyethylene, polypropylene, and polyvinylidene fluoride, or multilayers having two or more layers of these, can be used as separators.

[0088] The membrane may include a porous substrate and a coating comprising organic, inorganic or a combination thereof disposed on one or both sides of the porous substrate.

[0089] Organic materials may include polyvinylidene fluoride polymers or (meth)acrylic acid polymers.

[0090] Inorganic materials may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and combinations thereof, but this disclosure is not limited to these examples.

[0091] Organic and inorganic materials can be combined in a single coating. In other examples, the stack comprises a first coating of organic materials and a second coating of inorganic materials.

[0092] As is evident from the above description, according to embodiments of the present disclosure, at the joint region between the first housing and the second housing, the first housing includes a convex semi-circular cross-section, and the second housing includes a concave semi-circular cross-section. Therefore, a uniform and stable joint region can be formed between the first housing and the second housing.

[0093] According to embodiments of this disclosure, by applying a thermosetting resin including a photoinitiator to the second housing at the bonding region between the first housing and the second housing, a faster and more stable bonding can be ensured through the chemical reaction of the thermosetting resin.

[0094] According to embodiments of this disclosure, by applying an ultraviolet-blocking coating to the upper outer surface of the first housing above the joint area between the first housing and the second housing, it is possible to suppress temperature changes after the first housing and the second housing are joined at the joint area, thereby ensuring the reliability of battery protection of the battery housing.

[0095] Although this disclosure has been described above with reference to embodiments and accompanying drawings, this disclosure is not limited to the embodiments. Those skilled in the art to which this disclosure pertains can modify and alter this disclosure within the technical spirit of this disclosure.

Claims

1. A battery casing configured to accommodate a plurality of battery cells, the battery casing comprising: First shell; as well as The second housing is joined to the first housing at the joining area by laser bonding. The first housing has a convex semi-circular cross-sectional shape in the joint area.

2. The battery casing according to claim 1, wherein, The second housing has a concave semicircular cross-sectional shape in the joint region that corresponds to the convex semicircular cross-sectional shape of the first housing.

3. The battery casing according to claim 2, wherein, The first housing is made of a laser-transmissible material.

4. The battery casing according to claim 3, wherein, The second housing includes a receiving groove adjacent to the engagement area.

5. The battery casing according to claim 1, wherein, A thermosetting resin, including a photoinitiator, is disposed in the bonding area.

6. The battery casing according to claim 1, wherein, Above the joint area, an ultraviolet blocking coating is applied to the upper outer surface of the first housing.

7. The battery casing according to claim 6, wherein, The ultraviolet-blocking coating has a predetermined color.

8. A battery pack, the battery pack comprising: Multiple battery cells; as well as The battery casing is configured to house the plurality of battery cells. The battery casing includes a first casing and a second casing joined to the first casing at a joining area by laser bonding; and The first housing has a convex semi-circular cross-sectional shape in the joint area.

9. The battery pack according to claim 8, wherein, The second housing has a concave semicircular cross-sectional shape in the joint region that corresponds to the convex semicircular cross-sectional shape of the first housing.

10. The battery pack according to claim 9, wherein, The first housing is made of a laser-transmissible material.

11. The battery pack according to claim 10, wherein, The second housing includes a receiving groove formed adjacent to the engagement area.

12. The battery pack according to claim 8, wherein, A thermosetting resin, including a photoinitiator, is disposed in the bonding area.

13. The battery pack according to claim 8, wherein, Above the joint area, an ultraviolet blocking coating is applied to the upper outer surface of the first housing.

14. The battery pack according to claim 13, wherein, The ultraviolet-blocking coating has a predetermined color.

15. A method for manufacturing a battery pack, the method comprising: Manufacturing the first casing; Manufacture a second shell; Multiple battery cells are housed in the second housing; as well as The first housing and the second housing are joined at the joint area by laser bonding. The first housing has a convex semi-circular cross-sectional shape in the joint area.

16. The method according to claim 15, wherein, The second housing has a concave semicircular cross-sectional shape in the joint region that corresponds to the convex semicircular cross-sectional shape of the first housing.

17. The method according to claim 16, wherein, The first housing is made of a laser-transmissible material.

18. The method according to claim 17, wherein, The second housing includes a receiving groove adjacent to the engagement area.

19. The method according to claim 15, wherein, A thermosetting resin, including a photoinitiator, is disposed in the bonding area.

20. The method of claim 15, further comprising applying an ultraviolet-blocking coating to the upper outer surface of the first housing over the bonding area.

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