Battery module including cooling fins

Abstract

The present invention provides a battery module including a plurality of secondary batteries in a module case, the plurality of secondary batteries including two or more electrode assemblies each including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a non-aqueous electrolyte, and a pouch-type case including two or more storage sections that store the two or more electrode assemblies so that they are arranged laterally on a plane, and a connection section formed between the storage sections so that the two or more electrode assemblies can be electrically connected in series, the plurality of secondary batteries being stacked with the connection sections facing each other, respective separation spaces are formed between the plurality of secondary batteries at the connection sections, and respective cooling fins are positioned in the respective separation spaces.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0138935 filed on October 26, 2022 and Korean Patent Application No. 10-2023-0142116 filed on October 23, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module including a cooling fin, more specifically, a battery module including a plurality of secondary batteries, the secondary batteries having two or more electrode assemblies with shortened long sides housed in a pouch-type case including two or more storage compartments, and the secondary batteries are stacked, and cooling fins are provided in the spaces formed corresponding to the connections connecting the storage compartments. [Background technology]

[0003] The rapid increase in fossil fuel use has led to an increased demand for alternative and clean energy sources, with electrochemical generation and storage of electricity being one of the most actively researched areas.

[0004] At present, secondary batteries are a typical example of electrochemical elements that utilize such electrochemical energy, and the range of their use is expanding more and more.

[0005] In recent years, the demand for secondary batteries as energy sources has been rapidly increasing with technological development and increasing demand for mobile devices such as portable computers, mobile phones, and cameras. Among such secondary batteries, much research has been conducted on lithium secondary batteries, which have excellent charge / discharge characteristics and life characteristics and are environmentally friendly, and they have been commercialized and are widely used.

[0006] Furthermore, in recent years, secondary batteries have been developed to have higher energy density, higher output, longer life, and durability in response to user needs, and the voltage range of secondary batteries has expanded to 4.5V and above.

[0007] In response to this growing demand, lithium nickel cobalt manganese oxide, which has a high Ni content, has recently been used as a positive electrode material. However, the higher the Ni content, the higher the possibility of fire due to thermal runaway at high temperatures.

[0008] Meanwhile, in recent years, there has been a demand for larger capacity batteries, and there is a trend towards making batteries with longer long cells. At this time, in order to improve the safety of secondary batteries, the batteries are cooled on the outside of the secondary battery case, but it is difficult to cool the center of the battery, and as the cell cycles increase, heat builds up, making it difficult to ensure the safety of long cell batteries.

[0009] Therefore, as the demand for larger capacity increases, there is an urgent need to develop technology that can effectively prevent heat accumulation caused by battery operation and reduce the possibility of problems caused by thermal runaway. Summary of the Invention [Problem to be solved by the invention]

[0010] The problem to be solved by the present invention is to provide a battery module structure that can effectively prevent heat accumulation in the center portion that occurs when the secondary battery is operated, thereby reducing the possibility of thermal runaway. [Means for solving the problem]

[0011] In order to achieve this object, a battery module according to an embodiment of the present invention comprises: A battery module including a plurality of secondary batteries in a module case, each of the plurality of secondary batteries including two or more electrode assemblies including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a non-aqueous electrolyte, and a pouch-type case including two or more storage sections for storing the two or more electrode assemblies so as to be arranged in a horizontal direction on a plane, and a connection section formed between the storage sections so that the two or more electrode assemblies can be electrically connected in series, the plurality of secondary batteries being stacked such that their respective connection sections face each other, and respective separation spaces are formed between the plurality of secondary batteries at the connection sections, A cooling fin is disposed in each of the separated spaces.

[0012] In one specific example, the two or more electrode assemblies can include a first electrode assembly and a second electrode assembly.

[0013] Here, the first electrode assembly may include a first positive electrode tab extending from the positive electrode of the first electrode assembly and a first negative electrode tab extending from the negative electrode of the first electrode assembly, the second electrode assembly may include a second positive electrode tab extending from the positive electrode of the second electrode assembly and a second negative electrode tab extending from the negative electrode of the second electrode assembly, and the first electrode assembly and the second electrode assembly may be such that the first negative electrode tab and the second positive electrode tab are electrically connected by a connection lead. That is, the first electrode assembly and the second electrode assembly can be electrically connected in series by the connection lead.

[0014] In another specific example, the two or more storage sections may include a first storage section housing a first electrode assembly therein, and a second storage section housing a second electrode assembly therein, arranged laterally on a plane spaced apart from the first storage section, the second storage section being spaced apart from the first storage section, the connection section being formed between the first storage section and the second storage section to connect them, and a connection lead being located at the connection section.

[0015] Compared to two or more storage parts, such a connection part has a recessed structure in the stacking direction of the electrode assembly, and can form a separation space when multiple secondary batteries are stacked.

[0016] Specifically, the pouch-type case may include a lower case including two or more storage sections and a connection section, and an upper case covering the lower case.

[0017] Meanwhile, in such a battery module, the length of the short side of each of the two or more electrode assemblies on a plane may be 80% to 100% of the length of the long side.

[0018] Furthermore, two or more electrode assemblies may each have a fixing tape attached in the stacking direction so as to fix the electrode assemblies at their long sides on a plane.

[0019] In another specific example, the cooling fins may be additionally formed in a part of the space formed by the sealing portion of the pouch-type case when multiple secondary batteries are stacked. Specifically, the cooling fins may be additionally formed in the space formed by the sealing portion formed on one side of the pouch-type case in the overall length direction, which has a longer length on a plane, and on both sides in the overall width direction, which have a shorter length on a plane, when multiple secondary batteries are stacked.

[0020] Here, the cooling fins can be air-cooled or water-cooled.

[0021] In another specific example, the positive electrode comprises a positive electrode active material; The positive electrode active material may be a lithium transition metal oxide represented by the following chemical formula 1.

[0022] Li a Ni 1-b M b O 2-x A x (chemical formula 1) During the ceremony, M is at least one selected from the group consisting of Ti, Mg, Al, Zr, Mn, and Co; A is an oxygen-substituted halogen; 1.00≦a≦1.05, 0≦b≦0.3, and 0≦x≦0.01.

[0023] More specifically, M is (Mn c Co d ) where 0≦c≦1.0 and 0≦d≦1.0 may be satisfied.

[0024] The negative electrode may include a negative electrode active material, and the negative electrode active material may include a graphite-based material. [Brief description of the drawings]

[0025] [Figure 1] 1 is a see-through side view of a battery module according to an embodiment of the present invention; [Diagram 2] 2 is a partial enlarged view showing the arrangement of secondary batteries and cooling fins in the battery module of FIG. 1. [Diagram 3] FIG. 3 is an exploded top view of the secondary battery of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] In the following, the present invention will be described in more detail in order to better understand the present invention.

[0027] The terms and words used in the specification and claims of this application should not be interpreted limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept that is consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to best describe his / her invention.

[0028] The terms used in the present specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular form includes the plural form unless otherwise clearly indicated in the context.

[0029] Additionally, throughout this specification, when a part "comprises" a certain component, unless otherwise specified to the contrary, it does not mean that it excludes other components, but that it may further include other components.

[0030] A battery module according to an embodiment of the present invention includes: A battery module including a plurality of secondary batteries within a module case, each of the plurality of secondary batteries including two or more electrode assemblies including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a non-aqueous electrolyte, and a pouch-type case including two or more storage sections that store the two or more electrode assemblies so that they are arranged laterally on a plane, and a connection section formed between the storage sections so that the two or more electrode assemblies can be electrically connected in series, the plurality of secondary batteries are stacked with their respective connection sections facing each other, and respective separation spaces are formed between the plurality of secondary batteries at the connection sections, and each separation space has a cooling fin positioned therein.

[0031] That is, the secondary battery of the present application may have a structure in which two or more electrode assemblies are built into one pouch-type case and connected in series. Specifically, an electrode assembly that is originally manufactured as one is reduced in size to form two or more electrode assemblies, which are then connected in series to produce the same effect as forming a single electrode assembly.

[0032] However, as explained in the background art, the conventional long cell has a problem that the center part of the battery is not cooled well, resulting in heat accumulation and runaway. By forming such a long cell as two or more separate parts, it is possible to partially improve such problems.

[0033] Also, by locating cooling fins in the separated portions, the problems of heat build-up and thermal runaway in the center portion can be eliminated.

[0034] In order to describe this structure in more detail, a description will be given below with reference to Figures 1 to 3. To facilitate understanding, the description will be given based on the drawings according to one embodiment, but the scope of the present invention is not limited thereto.

[0035] FIG. 1 is a schematic see-through side view of a battery module according to one embodiment of the present invention.

[0036] Referring to FIG. 1, the battery module 200 has a structure in which a plurality of secondary batteries 210 are stacked facing each other in a module case 230, and in the stacked state, separation spaces are formed between the plurality of secondary batteries 210, and cooling fins 220 are formed in the separation spaces.

[0037] In this case, the separated space is formed at a portion where two or more electrode assemblies (described in more detail below) can be electrically connected in series, i.e., a portion corresponding to a connection portion of the pouch-type case, and may also be formed in a part of the space formed by the outer peripheral sealing portion of the pouch-type case. Specifically, the separated space may be additionally formed in the space formed by the sealing portion formed at one side of the pouch-type case in the full length direction, which is longer on a plane, and at both sides of the pouch-type case in the full width direction, which are shorter on a plane.

[0038] Therefore, according to the present invention, the cooling fins 220 can be positioned between the stacked secondary batteries 210, minimizing the increase in overall volume. Therefore, compared to the prior art, the total volume of the battery module 200 does not increase, and the cooling effect can be exerted even in the middle part of the secondary battery, which can further delay ignition and thereby prevent voltage drop.

[0039] Meanwhile, in order to specifically describe the secondary battery 210 and the cooling fins 220 of the battery module 200 of the present invention and to explain their formation relationship, FIG. 2 below shows an enlarged view of one secondary battery and cooling fins, and FIG. 3 shows an exploded top view of a secondary battery in which the pouch-type case is not sealed but is open.

[0040] With reference to both FIG. 2 and FIG. 3, for convenience of explanation, one secondary battery and one cooling fin will be referred to as a "secondary battery assembly."

[0041] In other words, the term "secondary battery assembly" is intended to indicate that it includes cooling fins formed externally in addition to the secondary battery, and is a concept that includes not only an integrally formed form, but also the case where cooling fins are simply located outside the secondary battery.

[0042] In a secondary battery assembly 100 according to one embodiment of the present invention, the secondary battery has two or more electrode assemblies 110, 120 housed in a pouch-type case 130 together with a non-aqueous electrolyte (not shown), and the two or more electrode assemblies 110, 120 are electrically connected in series to each other.

[0043] Specifically, the two or more electrode assemblies 110, 120 include a first electrode assembly 110 and a second electrode assembly 120, where the second electrode assembly 120 is aligned laterally with the first electrode assembly 110 on a plane.

[0044] Here, the first electrode assembly 110 has a structure including a first positive electrode 111, a first negative electrode 112, and a separation membrane 113 interposed between the first positive electrode 111 and the first negative electrode 112, and the second electrode assembly 120 has a structure including a second positive electrode 121, a second negative electrode 122, and a separation membrane 123 interposed between the second positive electrode 121 and the second negative electrode 122.

[0045] In addition, a first positive electrode tab 111a extends from the positive electrode 111 of the first electrode assembly 110, and a first negative electrode tab 112a extends from the negative electrode 112. A second positive electrode tab 121a extends from the positive electrode 121 of the second electrode assembly 120, and a second negative electrode tab 122a extends from the negative electrode 122. Here, the first negative electrode tab 112a and the second positive electrode tab 121a are electrically connected by a connection lead 150. Therefore, the first electrode assembly 110 and the second electrode assembly 120 can be electrically connected in series.

[0046] The first positive electrode tab 111a and the second negative electrode tab 122a, except for the first negative electrode tab 112a and the second positive electrode tab 121a used for the series connection, are connected to leads extending to the outside of the pouch-type case 130 in different directions.

[0047] Although the drawings disclose a secondary battery composed of two electrode assemblies, the number of electrode assemblies is not limited, and two or more can be connected in series. However, a space is required for the series connection, and a power generating element cannot be included in this portion. Therefore, in consideration of the energy density per volume, it is more preferable to configure the secondary battery with two electrode assemblies.

[0048] In the present invention, the secondary battery includes two or more electrode assemblies 110, 120 in order to prevent heat accumulation in the center by dividing a conventional long cell into two at the longer side, and the length (l1) of the short side of each of the two or more electrode assemblies 110, 120 on a plane may be 80% to 100% of the length (l2) of the long side. Specifically, it may be 90% to 100%.

[0049] In addition, the two or more electrode assemblies 110, 120 are not limited to those having conventional structures, and may have a structure in which unit electrodes and unit separators are alternately stacked, or may have a structure in which unit cells, for example, a full cell having electrodes of opposite polarity arranged on both sides, a bi-cell having electrodes of the same polarity arranged on both sides, or a mono-cell having one electrode and a separator stacked, are stacked.

[0050] In this case, in order to prevent misalignment when the respective components or unit cells are arranged relative to each other, two or more electrode assemblies 110, 120 may have fixing tapes 160 attached in the stacking direction so that the electrode assemblies 110, 120 are fixed to their respective long sides on a plane. In the drawings, a configuration in which each electrode assembly 110, 120 is fixed to each other by two pairs of fixing tapes is shown, but the number of such tapes is not limited.

[0051] Meanwhile, the secondary battery of the present invention includes two or more electrode assemblies 110, 120 in one secondary battery, and therefore includes a pouch-type case 130 having a special structure capable of housing them.

[0052] Specifically, the pouch-type case 130 includes two or more storage sections 131, 132 capable of storing two or more electrode assemblies 110, 120. Specifically, the two or more storage sections 131, 132 include a first storage section 131 housing the first electrode assembly 110 therein, and a second storage section 132 arranged in the horizontal direction on a plane spaced apart from the first storage section 131 and housing the second electrode assembly 120 therein.

[0053] The pouch-type case 130 includes a connection portion 133 that connects the first storage portion 131 and the second storage portion 132. In the connection portion 133, a connection lead 150 that connects the first negative electrode tab 112a and the second positive electrode tab 121a is located.

[0054] Therefore, the connection portion 133 located between the first storage portion 131 and the second storage portion 132 does not need a space large enough to store the electrode assemblies 110 and 120, and it is sufficient if the connection lead 150 is safely positioned. Therefore, as shown in Fig. 2, the connection portion forms a recessed structure in the stacking direction of the electrode assemblies 110 and 120 compared to the first storage portion 131 and the second storage portion 132.

[0055] Therefore, such recesses form separation spaces when the secondary batteries are stacked as shown in FIG. 1, and the cooling fins 141, which will be described later, can be effectively positioned in the separation spaces.

[0056] The structure of the pouch-type case 130 may be a sealed case formed as one piece, or may be separated into an upper case and a lower case, and may include, but is not limited to, a structure including, for example, a lower case 134 including a first receiving section 131, a second receiving section 132, and a connecting section 133, and an upper case 135 that covers the lower case 134 and is then sealed, in order to effectively form a space between the upper case 135 and the lower case 134. The pouch-type case 130 may be formed of an aluminum laminate sheet, and the material forming the pouch-type case 130 is disclosed in detail in the art, and therefore, a description thereof will be omitted in this specification.

[0057] Meanwhile, in the past, it was not possible to position a cooling fin in the center of the pouch-type case 130, but according to the present invention, by positioning two electrode assemblies 110, 120 in a case including two storage sections 131, 132, a connection section is formed at the recess between the storage sections 131, 132, and when multiple secondary batteries are stacked from these, a separation space is formed and a cooling fin 141 can be positioned, so that cooling can be performed even in the center of the secondary battery.

[0058] Therefore, the conventional problem of heat accumulation in the center portion can be prevented, and the possibility of thermal runaway can be significantly reduced.

[0059] In order to cool the entire secondary battery, cooling fins 142 may also be formed in part of the space formed by the sealing portion of pouch-type case 130, as shown in FIGS.

[0060] Specifically, the cooling fins 142 are additionally formed in the space formed by the sealing parts formed on one side surface in the overall length direction, which is longer on a plane of the pouch-type case 130, and on both side surfaces in the overall width direction, which are shorter on a plane. Of course, the cooling fins 142 may be formed on all the side surfaces.

[0061] Here, the cooling fins are not limited as long as they have a conventionally known configuration, and may be, for example, air-cooled or water-cooled cooling fins. Specifically, in order to further enhance the cooling performance, water-cooled cooling fins may be used.

[0062] Here, the cooling fins 141 located between the storage sections 131, 132 and the secondary battery sealing section, i.e., the cooling fins 142 that wrap around the outer peripheral surface of the secondary battery, may be, but are not limited to, connected to each other or formed separately, but specifically, it is preferable that they are connected to each other.

[0063] With such a structure, it is possible to effectively cool the battery while having an energy density and capacity similar to those of a long cell, and thus to improve safety.

[0064] Meanwhile, components included in such a secondary battery will be specifically described below.

[0065] The positive electrode includes a positive electrode active material, The positive electrode active material may be a lithium transition metal oxide represented by the following chemical formula 1.

[0066] Li a Ni 1-b M b O 2-x A x (chemical formula 1) During the ceremony, M may be one or more selected from the group consisting of Ti, Mg, Al, Zr, Mn, and Co; A is an oxygen-substituted halogen; 1.00≦a≦1.05, 0≦b≦0.3, and 0≦x≦0.01.

[0067] Specifically, M is (Mn c Co d ) where 0≦c≦1.0 and 0≦d≦1.0 may be satisfied. That is, in the secondary battery assembly according to the present application, the positive electrode may be a lithium nickel-based transition metal oxide having a high Ni content, in which Ni is 0.7 or more.

[0068] When such an oxide with a high Ni content is used as a positive electrode active material, it has advantages such as a large capacity and a high energy density, but has a problem with high temperature safety, and is therefore more suitable for a secondary battery assembly having the structure as described in the present application.

[0069] More specifically, the molar ratio of Ni may be 0.8 to 0.9, that is, 0.1≦b≦0.2.

[0070] In addition to the positive electrode active material represented by Chemical Formula 1, the positive electrode may be made of layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; 1+x Mn 2-x O4 (where x is 0 to 0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, and Cu2V2O7; and the chemical formula LiNi 1-x M x Lithium nickel oxide with Ni site represented by the chemical formula LiMnO2 (where M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3). 2-x M x The lithium manganese composite oxides represented by Li2Mn3MO8 (wherein M is Co, Ni, Fe, Cr, Zn or Ta, and x is 0.01 to 0.1) or Li2Mn3MO8 (wherein M is Fe, Co, Ni, Cu or Zn); LiMn2O4 in which part of the Li in the chemical formula is replaced with an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, etc. may be included, and may be used in a mixed form.

[0071] Furthermore, the positive electrode can be configured to have a structure in which a positive electrode material containing a positive electrode active material is formed on a positive electrode current collector, and the positive electrode material can further contain a conductive material, a binder, and if necessary, a filler, etc., in addition to the positive electrode active material.

[0072] The conductive material is used to impart conductivity to the electrode, and can be used without any particular restrictions as long as it does not cause a chemical change in the battery that is constructed and has electronic conductivity. Specific examples include carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; graphite such as natural graphite and artificial graphite; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive polymers such as polyphenylene derivatives, and one or a mixture of two or more of these can be used. The conductive material may be contained in an amount of 1% by weight to 30% by weight, specifically 1% by weight to 10% by weight, and more specifically 1% by weight to 5% by weight, based on the total weight of the positive electrode material.

[0073] The binder plays a role of improving the adhesion between the positive electrode active material particles and the adhesive strength between the positive electrode active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one or more of these can be used alone or in combination. The binder may be included in an amount of 1% by weight to 30% by weight, specifically 1% by weight to 10% by weight, more specifically 1% by weight to 5% by weight, based on the total weight of the positive electrode material.

[0074] The filler is optionally used as a component that suppresses expansion of the electrode, and is not particularly limited as long as it does not cause a chemical change in the battery and is a fibrous material. For example, olefin polymers such as polyethylene and polypropylene; glass fiber, carbon fiber, and other fibrous substances are used, and the filler may be contained in an amount of 0 to 10% by weight based on the total weight of the positive electrode material.

[0075] The positive electrode current collector is not particularly limited as long as it does not cause a chemical change in the battery and has conductivity, and for example, stainless steel, aluminum, nickel, titanium, baked carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. can be used. In addition, the positive electrode current collector can have a thickness of 3 μm to 500 μm, and fine irregularities can be formed on the collector surface to increase the adhesive strength of the positive electrode active material. For example, it can be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0076] The negative electrode can also be configured with a structure in which a negative electrode material containing a negative electrode active material is formed on a negative electrode current collector. The negative electrode material can further contain a conductive material, a binder, and, if necessary, a filler, together with the negative electrode active material, as described above.

[0077] As the negative electrode active material, a compound capable of reversible insertion and desorption of lithium can be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys, or Al alloys; metal oxides such as SiO x (0 < x < 2), SnO2, vanadium oxides, and metal oxides capable of doping and undoping lithium such as lithium vanadium oxides; or composites containing metallic compounds and carbonaceous materials such as Si-C composites or Sn-C composites, etc. can be mentioned, and any one or a mixture of two or more of these can be used. Also, a thin film of metallic lithium can be used as the negative electrode active material. Also, as the carbon material, all of low-crystalline carbon and highly crystalline carbon can be used. Representative examples of low-crystalline carbon are soft carbon and hard carbon, and representative examples of highly crystalline carbon are amorphous, plate-like, flaky, spherical, or fibrous natural graphite or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum and coal tar pitch derived cokes. However, in detail, it can contain graphite-based substances.

[0078] The negative electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity, and examples of the material that can be used include copper, stainless steel, aluminum, nickel, titanium, baked carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, and aluminum-cadmium alloys. The negative electrode current collector can usually have a thickness of 3 μm to 500 μm, and like the positive electrode current collector, the current collector surface can be formed with fine irregularities to strengthen the binding force of the negative electrode active material. For example, the negative electrode current collector can be used in various forms such as a film, sheet, foil, net, porous body, foam, and nonwoven fabric.

[0079] The separator separates the negative electrode and the positive electrode to provide a path for lithium ions to move, and can be used without any particular restrictions as long as it is generally used as a separator in a lithium secondary battery. In particular, it is preferable that the separator has a low resistance to the ion movement of the electrolyte and a high moisture retention property for the electrolyte. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminate structure of two or more layers thereof can be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric such as a high-melting glass fiber or a polyethylene terephthalate fiber, can be used. In addition, a coated separator containing a ceramic component or a polymeric substance can be used to ensure heat resistance or mechanical strength, and can be used in a single layer or multilayer structure as desired.

[0080] In addition, examples of the non-aqueous electrolyte used in the present invention include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in manufacturing lithium secondary batteries, but are not limited to these.

[0081] Specifically, the non-aqueous electrolyte can include an organic solvent and a lithium salt.

[0082] The organic solvent can be used without any particular limitation as long as it can act as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent can be an ester solvent such as methyl acetate, ethyl acetate, γ-butyrolactone, ε-caprolactone, etc.; an ether solvent such as dibutylether or tetrahydrofuran, etc.; a ketone solvent such as cyclohexanone, etc.; an aromatic hydrocarbon solvent such as benzene or fluorobenzene, etc.; dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate (propylene carbonate), etc. Examples of the solvents that can be used include carbonate-based solvents such as ethylene carbonate (PC), alcohol-based solvents such as ethyl alcohol and isopropyl alcohol, nitriles such as R-CN (R is a C2-C20 straight-chain, branched or cyclic hydrocarbon group that can contain a double bond aromatic ring or an ether bond), amides such as dimethylformamide, dioxolanes such as 1,3-dioxolane, and sulfolanes. Among these, carbonate-based solvents are preferred, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of a battery and a low viscosity linear carbonate compound (e.g., ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, etc.) is more preferred. In this case, the performance as an electrolyte is improved when the cyclic carbonate and the linear carbonate are mixed at a volume ratio of about 1:1 to about 1:9.

[0083] The lithium salt can be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt can be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. The concentration of the lithium salt is preferably within the range of 0.1M to 2.0M. When the concentration of the lithium salt is within this range, the electrolyte has appropriate conductivity and viscosity, resulting in excellent electrolyte performance and allowing the lithium ions to move effectively.

[0084] In addition to the constituents, the non-aqueous electrolyte may further contain one or more additives such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethyl phosphate, triethanolamine, cyclic ethers, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinoneimine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing the decrease in battery capacity, improving the discharge capacity of the battery, etc. In this case, the additives may be contained in an amount of 0.1% by weight to 5% by weight based on the total weight of the non-aqueous electrolyte.

[0085] As described above, the battery module according to the present invention can be used as a device power source in portable devices such as mobile phones, notebook computers, digital cameras / cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

[0086] Methods of manufacturing battery modules, other than the above-mentioned structural changes, are known in the art and will not be described further herein.

[0087] Those skilled in the art will appreciate that the above-described content will enable various applications and modifications within the scope of the present invention. [Industrial Applicability]

[0088] As described above, according to the present invention, by providing a battery module having a structure in which the size of the electrode assemblies of the secondary batteries can be reduced while increasing the number of them can be connected in series and additional cooling fins can be placed at the connection sites, it is possible to effectively prevent heat accumulation in the center portion that occurs when the secondary battery is operated and reduce the possibility of thermal runaway. [Explanation of symbols]

[0089] 100 Secondary battery assembly 110 First electrode assembly 111 1st positive electrode 112 1st negative electrode 113 First separation membrane 111a 1st positive electrode tab 112a First negative electrode tab 120 Second electrode assembly 121 2nd positive electrode 122 Second negative electrode 123 Second separation membrane 121a 2nd positive electrode tab 122a Second negative electrode tab 130 Pouch Case 131 First storage section 132 Second storage section 133 Connection 141, 142 Cooling fins 150 Connection Leads 160 Fixing Tape

Claims

1. A battery module including a plurality of secondary batteries in a module case, The plurality of secondary batteries include Two or more electrode assemblies, each of which includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; A non-aqueous electrolyte; A pouch-type case, two or more storage sections for storing the two or more electrode assemblies so as to be arranged in a lateral direction on a plane; a connection portion formed between the storage portions so that the two or more electrode assemblies can be electrically connected in series; and the plurality of secondary batteries are stacked such that the connection portions face each other, and separation spaces are formed between the plurality of secondary batteries at the connection portions; The battery module has cooling fins disposed in each of the separated spaces.

2. the two or more electrode assemblies include a first electrode assembly and a second electrode assembly; the first electrode assembly includes a first positive electrode tab extending from a positive electrode of the first electrode assembly and a first negative electrode tab extending from a negative electrode of the first electrode assembly; the second electrode assembly includes a second positive electrode tab extending from a positive electrode of the second electrode assembly and a second negative electrode tab extending from a negative electrode of the second electrode assembly; The battery module according to claim 1 , wherein the first negative electrode tab and the second positive electrode tab are electrically connected by a connection lead.

3. The two or more storage sections include: a first housing portion housing the first electrode assembly; a second receiving portion arranged in a horizontal direction on a plane spaced apart from the first receiving portion and housing the second electrode assembly; The battery module according to claim 2 , wherein the connection portion is formed between the first storage portion and the second storage portion to connect them.

4. The battery module according to claim 3 , wherein the connection lead is located at the connection portion.

5. 5. The battery module according to claim 1, wherein the connection portion has a recessed structure in a stacking direction of the electrode assembly compared to the two or more storage portions, and forms the separation space when the plurality of secondary batteries are stacked.

6. The pouch-type case is a lower case including the two or more storage sections and a connection section; The battery module according to claim 1 , further comprising: an upper case covering the lower case.

7. The battery module according to claim 1 , wherein the length of a short side of each of the two or more electrode assemblies on a plane is 80% to 100% of the length of a long side of each of the two or more electrode assemblies.

8. The battery module according to claim 1 , wherein the two or more electrode assemblies have a fixing tape attached in a stacking direction so as to fix the electrode assemblies at their long sides on a plane.

9. The battery module according to claim 1 , wherein the cooling fins are additionally formed in a part of a space formed by a sealing portion of the pouch-type case when the plurality of secondary batteries are stacked.

10. 10. The battery module according to claim 9, wherein the cooling fins are additionally formed in a space defined by a sealing portion formed on one side surface of the pouch-type case in a longitudinal direction that is longer than the other side surface of the pouch-type case in a plan view and on both side surfaces of the pouch-type case in a width direction that is shorter than the other side surface of the pouch-type case in a plan view when a plurality of secondary batteries are stacked.

11. The battery module according to claim 1 , wherein the cooling fins are air-cooled or water-cooled.

12. The positive electrode includes a positive electrode active material, The positive electrode active material is a lithium transition metal oxide represented by the following formula 1: Li ａ Ni １－ｂ M ｂ O ２－ｘ A ｘ (Chemical formula 1) During the ceremony, M is at least one selected from the group consisting of Ti, Mg, Al, Zr, Mn, and Co; A is an oxygen-substituted halogen; The battery module according to claim 1 , wherein 1.00≦a≦1.05, 0≦b≦0.3, and 0≦x≦0.

01.

13. The M is (Mn ｃ Co ｄ ) and 0≦c≦1.0, The battery module according to claim 12 , wherein 0≦d≦1.

0.

14. The negative electrode includes a negative electrode active material, The battery module according to claim 1 , wherein the negative electrode active material comprises a graphite-based material.

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