Battery module

Abstract

A battery module according to exemplary embodiments includes a plurality of battery cells and a cooling unit, and the battery cells may include an electrode assembly and an electrolyte storage unit disposed between the electrode assembly and the cooling unit in a cross-sectional direction.

Description

Technology Field

[0001] The present invention relates to a battery module. More specifically, it relates to a battery module comprising a plurality of battery cells. Background Technology

[0002] Rechargeable batteries are batteries capable of repeated charging and discharging, such as lithium-ion batteries, nickel-cadmium batteries, and nickel-hydrogen batteries.

[0003] Lithium-ion batteries are being actively developed and applied due to their high operating voltage and energy density per unit weight, as well as their advantages in charging speed and weight reduction.

[0004] For example, low-capacity lithium-ion batteries can be used as a power source for small electronic devices such as cellular phones, laptop computers, and camcorders. In addition, high-capacity lithium-ion batteries can be used as a power source for large electronic devices such as hybrid vehicles.

[0005] For example, a lithium secondary battery may include an electrode assembly comprising a positive electrode, a negative electrode, and, if necessary, a separator interposed between the positive electrode and the negative electrode; and a case (cell case, e.g., a pouch-type case) for housing the electrode assembly and an electrolyte impregnating the electrode assembly.

[0006] The above lithium secondary battery can be defined as a battery cell, and a plurality of battery cells can be housed within a case (module case) to form a battery module.

[0007] Meanwhile, the battery cell can be charged and discharged through the electrochemical reaction of the anode, the cathode, and the electrolyte.

[0008] However, if the battery cell is repeatedly charged and discharged, the electrolyte may be degraded due to side reactions, causing the amount of electrolyte inside the battery cell to gradually decrease. Consequently, the capacity retention rate of the battery cell may gradually decrease, and the lifespan of the battery module may end.

[0009] For example, Korean Patent Publication No. 10-2011-0132856 discloses a method for replenishing electrolyte to a battery cell. Prior art literature

[0010] Republic of Korea Published Patent Application No. 10-2011-0132856 The problem to be solved

[0011] One objective of the present invention is to provide a battery module having improved operational stability and lifespan. means of solving the problem

[0012] A battery module according to exemplary embodiments may include: a cell stack comprising a plurality of battery cells; a module case that accommodates the cell stack at least partially; and a cooling unit disposed on one side of the cell stack.

[0013] Each of the above battery cells may include: a cell case; an electrode assembly and an electrolyte accommodated within the cell case; and an electrolyte storage unit inserted within the cell case to supply a supplementary electrolyte and disposed between the electrode assembly and the cooling unit in the cross-sectional direction.

[0014] In one embodiment, the outer surface of the electrolyte storage unit facing the cooling unit may include a flat surface.

[0015] In one embodiment, in the cross-sectional direction, the flat surface of the electrolyte storage unit and the bottom surface of the cell case are in surface contact, and the bottom surface of the cell case and the top surface of the cooling unit may be in surface contact.

[0016] In one embodiment, the bottom surface of the cell case may be a non-sealing surface.

[0017] In one embodiment, the electrolyte storage unit may have the shape of a polygonal column.

[0018] In one embodiment, the longitudinal direction of the electrode assembly and the longitudinal direction of the electrolyte storage unit may be parallel.

[0019] In one embodiment, the electrolyte storage unit may include a first unit comprising a first body having a polygonal column shape and a tubular hollow, and first holes formed in the first body; and a sub-unit comprising a tubular body and sub-holes formed in the tubular body, wherein the sub-holes are inserted into the first unit such that they are offset from the first holes.

[0020] In one embodiment, the electrolyte storage unit further comprises a second unit including a second body having a tubular structure and second holes formed in the second body, and the second unit may be inserted between the first unit and the sub-unit such that at least one of the second holes overlaps with at least one of the first holes.

[0021] In one embodiment, the battery module comprises a first sub-unit and a second sub-unit, each inserted into the ends of the first unit.

[0022] In one embodiment, the second holes may be arranged so as to be offset from the sub-holes.

[0023] In one embodiment, the inner surface of the first body and the outer surface of the second body may each have a screw structure so as to be fastened to each other.

[0024] In one embodiment, the first unit has a first thermal expansion coefficient, and the second unit may have a second thermal expansion coefficient different from the first thermal expansion coefficient.

[0025] In one embodiment, at a temperature of -20°C or lower or 40°C or higher, the second unit may be physically separable from the first unit.

[0026] In one embodiment, the first sub-unit and the second sub-unit may be arranged within the first unit such that they are spaced apart from each other in the longitudinal direction of the first unit.

[0027] In one embodiment, the first sub-unit and the second sub-unit may be movable by an external force in the longitudinal direction such that at least one of the sub-holes overlaps with at least one of the first holes.

[0028] In one embodiment, the electrolyte storage unit may further include a first packing portion coupled to one end of the first sub-unit; and a second packing portion coupled to one end of the second sub-unit.

[0029] In one embodiment, the cell case may include a first space for accommodating the electrode assembly and the electrolyte; a second space into which the electrolyte storage unit is inserted; and a passage portion through which the replenishing electrolyte can move between the first space and the second space.

[0030] In one embodiment, the passage portion may include a sealing line portion that can be opened by pressure from the discharge of the supplementary electrolyte. Effects of the invention

[0031] A battery module according to exemplary embodiments may include a plurality of battery cells, and the battery cell may include a cell case; an electrode assembly and an electrolyte accommodated in the main chamber of the cell case; and an electrolyte storage unit comprising a replenishing electrolyte. When the electrolyte in the battery cell is consumed, the electrolyte may be replenished by the electrolyte storage unit. Accordingly, the battery module may have improved lifespan characteristics.

[0032] In one embodiment, the outer surface of the electrolyte storage unit may include a flat surface. Additionally, in the battery module, the flat surface of the electrolyte storage unit may be positioned to face the cooling unit. Accordingly, the battery module may have improved cooling efficiency. Brief explanation of the drawing

[0033] FIG. 1 is a schematic planar perspective view of a battery cell according to exemplary embodiments. FIG. 2 is a schematic plan view of a first unit according to exemplary embodiments. FIGS. 3 and FIGS. 4 are schematic plan views of a first sub-unit and a second sub-unit according to exemplary embodiments, respectively. FIG. 5 is a schematic plan view of a second unit according to exemplary embodiments. FIG. 6 is a planar perspective view schematically showing a structure in which a second unit according to exemplary embodiments is inserted into a first unit. FIG. 7 is a planar perspective view schematically showing a structure in which a first sub-unit and a second sub-unit are inserted into a second unit according to exemplary embodiments. FIG. 8 is a schematic diagram illustrating a mechanism for opening a sealed space formed by a second unit, a first sub-unit, and a second sub-unit according to exemplary embodiments. FIG. 9 is a schematic diagram illustrating a mechanism for replacing a second unit to a second sub-unit according to exemplary embodiments. FIG. 10 is a schematic cross-sectional view of an electrode assembly according to exemplary embodiments. FIG. 11 is a schematic exploded perspective view of a battery module according to exemplary embodiments. FIG. 12 is a schematic cross-sectional view of a battery module according to exemplary embodiments. Specific details for implementing the invention

[0034] According to the present invention, a battery module comprising a plurality of battery cells is provided. Hereinafter, for convenience of explanation, the battery cells are described first, and then the battery module is described.

[0035] battery cell

[0036] Hereinafter, a battery cell according to exemplary embodiments will be described in more detail with reference to the drawings. However, the drawings and embodiments are merely illustrative and the present invention is not limited thereto.

[0037] Referring to FIG. 1, a battery cell (1) may include an electrode assembly (150); an electrolyte (not shown) impregnating the electrode assembly (150); an electrolyte storage unit (5) containing a replenishing electrolyte; and a cell case (160) accommodating the electrode assembly (150), the electrolyte, and the electrolyte storage unit (5). For example, the electrolyte storage unit (5) may be inserted into the cell case (160) adjacent to the electrode assembly (150).

[0038] In one embodiment, the cell case (160) includes a space, and the electrode assembly (150), the electrolyte, and the electrolyte storage unit (5) can be accommodated in the space.

[0039] In one embodiment, the cell case (160) may include an electrode assembly (150), a first space (172) for accommodating the electrolyte, and a second space (174) into which an electrolyte storage unit (5) is inserted.

[0040] In some embodiments, a passage section (176) may be formed between the first space (172) and the second space (174). For example, the replenishing electrolyte contained in the electrolyte storage unit (5) may move to the first space (172) through the passage section (176).

[0041] In one embodiment, the first space (172) and the second space (174) may be formed side by side inside the cell case (160). Additionally, the electrode assembly (150) and the electrolyte storage unit (5) may be arranged side by side.

[0042] In one embodiment, as shown in FIG. 1, the longitudinal direction of the electrode assembly (150) and the longitudinal direction of the electrolyte storage unit (5) may be parallel.

[0043] For example, the longitudinal direction of the electrode assembly (150) may mean a direction parallel to the long side direction of the anode (or cathode).

[0044] Additionally, for example, the longitudinal direction of the electrolyte storage unit (5) may mean a direction parallel to the direction in which the electrolyte storage unit (5) is inserted into the cell case (160). Likewise, the longitudinal direction of the first unit (10), the longitudinal direction of the second unit (20), and the longitudinal direction of the sub-units (first sub-unit and second sub-unit) described later may mean a direction parallel to the direction in which the electrolyte storage unit (5) is inserted into the cell case (160).

[0045] In one embodiment, the second space (174) may extend in the longitudinal direction of the electrode assembly (150). Accordingly, the longitudinal length of the electrode assembly (150) and the longitudinal length of the electrolyte storage unit (5) may correspond to each other. In one embodiment, the height of the first space (172) and the height of the electrolyte storage unit (5) may be the same. In this case, the battery cell (1) may have a constant thickness (if the battery cell includes a passage section, the battery cell may have the same thickness in the area excluding the passage section).

[0046] In one embodiment, the cell case (160) may be a pouch-type case and may include four outer peripheries. In some embodiments, the outer periphery may include three sealing portions (162, 164, 166) and a non-sealing portion (168). For example, the non-sealing portion (168) may be formed by folding a sheet.

[0047] For example, the first space (172) may include a closed space. For example, the second space (174) may include a closed space or a space with at least one end open.

[0048] For example, the outer surface of the electrolyte storage unit (5) (for example, the outer surface of the first unit (10)) may be in close contact with the inner surface of the second space (174) so ​​that the supplementary electrolyte does not leak out of the cell case (160).

[0049] The electrolyte storage unit (5) may include a first unit (10) and a sub-unit inserted within the first unit (10).

[0050] Referring to FIG. 2, the first unit (10) may include a first body (12) having a tubular hollow and first holes (14) formed in the first body. For example, the first body (12) may have a tubular hollow with both ends open. For example, at least one of the first holes (14) may be connected to a passage portion (176).

[0051] In one embodiment, the first body (12) may include a flat area formed along the longitudinal direction of the first unit (10) on at least a portion of its outer surface. The first body (12) may also include a curvature area on at least a portion of its outer surface.

[0052] In some embodiments, the first body (12) may have the shape of a polygonal column (in this specification, a polygonal column includes cases where the sides have curvature, provided that at least one side has a flat shape). In some embodiments, the first body (12) may have the shape of a square column.

[0053] In some embodiments, the first holes (14) may be formed in a row on the first body (12) along the longitudinal direction of the first unit (10).

[0054] The above sub-unit includes a body having a tubular structure (hereinafter abbreviated as tubular body) and sub-holes formed in the tubular body, and the sub-holes may be inserted into the first unit (10) such that they are offset from the first holes (14). Accordingly, a sealed space may be formed within the first unit (10) and the sub-unit. The supplementary electrolyte may be contained in the sealed space.

[0055] In some embodiments, the sub-holes may be formed in a row in the tubular body along the longitudinal direction of the sub-unit.

[0056] In one embodiment, the sub-unit may include a first sub-unit (30) and a second sub-unit (40). For example, the first sub-unit (30) and the second sub-unit (40) may each be inserted into both ends of the first unit (10).

[0057] In some embodiments, the first sub-unit (30) and the second sub-unit (40) may be arranged within the first unit (10) so as to be spaced apart from each other in the longitudinal direction of the first unit (10).

[0058] Referring to FIG. 3, the first sub-unit (30) may include a first tubular body (32) and first sub-holes (34) formed in the first tubular body (32). For example, the first tubular body (32) may have a tubular structure in which one end is closed and the other end (the end opposite the one end in the longitudinal direction) is open.

[0059] In some embodiments, the first sub-holes (34) may be formed in a row on the first tubular body (32) along the longitudinal direction of the first sub-unit (30).

[0060] Referring to FIG. 4, the second sub-unit (40) may include a second tubular body (42) and second sub-holes (44) formed in the second tubular body (42). For example, the second tubular body (32) may have a tubular structure with one end closed and the other end open.

[0061] In some embodiments, the second sub-holes (44) may be formed in a row on the second tubular body (42) along the longitudinal direction of the second sub-unit (40).

[0062] In one embodiment, the electrolyte storage unit (5) may further include a second unit (20) inserted between the first unit (10) and the sub-unit.

[0063] Referring to FIG. 5, the second unit (20) may include a second body (22) having a tubular structure and second holes (24) formed in the second body (22). For example, the second body (22) may have a tubular structure with both ends open.

[0064] In some embodiments, the second holes (24) may be formed in a row on the second body (22) along the longitudinal direction of the second unit (20).

[0065] Referring to FIG. 6, a second unit (20) may be inserted into the first unit (10) such that at least one of the second holes (24) overlaps with at least one of the first holes (14). A sub-unit (30, 40, not shown in FIG. 6) may be inserted into the second unit (20). Accordingly, the second unit (20) may be positioned between the first unit (10) and the sub-unit.

[0066] In some embodiments, as shown in FIG. 6, the first unit (10) and the second unit (20) may each include the same number of holes. For example, the first holes (14) and the second holes (24) may each be arranged to overlap.

[0067] Referring to FIG. 7, the first sub-unit (30) and the second sub-unit (40) may be inserted into the second unit (20). For example, the first sub-unit (30) and the second sub-unit (40) may be inserted from each end of the second unit. For example, the first sub-unit (30) and the second sub-unit (40) may be arranged within the second unit (20) so as to be spaced apart from each other along the length of the second unit (20).

[0068] In some embodiments, the first holes, second holes, first sub-holes and second sub-holes (12, 22, 32, 43) may be arranged in a line along the longitudinal direction of the first unit (10).

[0069] For example, the sealed end portion of the first sub-unit (30) and the sealed end portion of the second sub-unit (40) may be arranged to face the outside of the cell case (160). For example, the second holes (24), the holes (34) of the first sub-unit, and the holes (44) of the second sub-unit may be arranged so as to be offset from each other. Accordingly, a sealed space (50) may be formed within the second unit (20), the first sub-unit (30), and the second sub-unit (40). The supplementary electrolyte may be contained in the sealed space (50).

[0070] In one embodiment, as illustrated in FIG. 3, the first sub-unit (30) may include a first packing portion (36) coupled to one end. In some embodiments, the first packing portion (36) may be disposed on the outer surface of the sealed end side of the first tubular body (32). For example, the first packing portion (36) may be disposed between the second unit (20) and the first sub-unit (30). The sealing performance of the sealed space (50) may be improved by the first packing portion (36).

[0071] In some embodiments, the first packing portion (36) may be positioned to wrap around the outer surface of the sealed end portion of the first tubular body (32).

[0072] In one embodiment, as illustrated in FIG. 4, the second sub-unit (40) may include a second packing portion (46) coupled to one end. In some embodiments, the second packing portion (46) may be disposed on the outer surface of the sealed end side of the second tubular body (42). For example, the second packing portion (46) may be disposed between the second unit (20) and the second sub-unit (40). The sealing performance of the sealed space (50) may be improved by the second packing portion (46).

[0073] In some embodiments, the second packing portion (46) may be positioned to wrap around the outer surface of the sealed end portion of the second tubular body (42).

[0074] In some embodiments, the first sub-unit (30) and the second sub-unit (40) may each have packing portions attached to the opposite end (i.e., the other end) of the first end. Accordingly, the sealing performance of the sealed space (50) may be further improved.

[0075] In one embodiment, the material of the packing portion may be an elastic material.

[0076] In some embodiments, the elastic material may include natural rubber, synthetic rubber, elastomer, etc.

[0077] For example, the above elastomer may include polyolefin-based elastomers, urethane-based elastomers, styrene-based block copolymers, vinyl chloride-based elastomers, chlorinated polyethylene-based elastomers, polyester-based elastomers, polyamide-based elastomers, fluorine-based elastomers, silicone-based elastomers, etc. Among these, a material having chemical resistance to the electrolyte is preferred.

[0078] In one embodiment, the material of the packing portion may be a polyolefin resin. For example, the polyolefin resin may include polyethylene, etc.

[0079] For example, if the battery cell (1) is repeatedly charged and discharged, at least a portion of the electrolyte contained in the first space (172) may be depleted.

[0080] In one embodiment, at least one of the first sub-unit (30) and the second sub-unit (40) may be movable by an external force in a direction in which the volume of the sealed space (50) is reduced (e.g., in the longitudinal direction of the first unit) within the first unit (10).

[0081] For example, as the first sub-unit (30) moves, at least one of the first sub-holes (34) is positioned to overlap with at least one of the first holes (14), so that the sealed space (50) can be opened. For example, as the second sub-unit (40) moves, at least one of the second sub-holes (44) is positioned to overlap with at least one of the first holes (14), so that the sealed space (50) can be opened.

[0082] For example, the supplementary electrolyte may be discharged into the first space (172) by passing through at least one of the first sub-holes (34) and the second sub-holes (44), at least one of the first holes (14), and the passage section (176).

[0083] Referring to FIG. 8(A) and FIG. 8(B), an electrolyte replenishment mechanism according to exemplary embodiments will be described in more detail.

[0084] Referring to FIG. 8(A), the sealed end portion of the first sub-unit (30) and the sealed end portion of the second sub-unit (40) may each be positioned to face the outside of the cell case (160). Additionally, the second holes (24), the first sub-holes (34), and the second sub-holes (44) may be positioned offset from each other to form a sealed space (50) within the second unit (20), the first sub-unit (30), and the second sub-unit (40). A supplementary electrolyte may be contained in the sealed space (50).

[0085] Referring to FIG. 8(B), by means of an external force, the first sub-unit (30) and the second sub-unit (40) within the second unit (20) may be moved in a direction in which the volume of the sealed space (50) is reduced (e.g., in the longitudinal direction of the second unit) so that at least one of the second holes (24), the first sub-holes (34), and the second sub-holes (44) may overlap. Accordingly, the sealed space (50) may be opened.

[0086] As shown in FIG. 6, the first holes (14) and the second holes (24) may be arranged overlapping each other. Thus, when the sealed space (50) is opened, the supplementary electrolyte can be moved to the first space (172) through the first holes (14) and the passage section (176).

[0087] As described above, the lithium secondary battery according to the exemplary embodiments can replenish the electrolyte while maintaining the sealing of the first space (172). Accordingly, damage to the lithium secondary battery caused by the intrusion of external air and moisture during electrolyte replenishment can be prevented.

[0088] In some embodiments, as shown in FIG. 1, the passage section (176) may include a sealing line section (178). Accordingly, the sealing of the first space (172) can be further improved. For example, the sealing line section (178) may be opened by pressure resulting from the discharge of the supplemental electrolyte.

[0089] In one embodiment, the first unit (10) has a first thermal expansion coefficient, and the second unit (20) may have a second thermal expansion coefficient different from the first thermal expansion coefficient. For example, the thermal expansion coefficient may refer to a linear expansion coefficient.

[0090] For example, when the electrolyte storage unit (5) is exposed to a temperature below a predetermined temperature (e.g., -20°C, preferably -30°C or lower) or above a predetermined temperature (e.g., 40°C or higher, preferably 50°C or higher), a gap may occur between the first unit (10) and the second unit (20). For example, the electrolyte storage unit (5) may be cooled or heated to a predetermined temperature to form a gap between the first unit (10) and the second unit (20).

[0091] For example, the second unit (20) can be physically separated from the first unit (10) by the gap. For example, at room temperature, the gap is not formed, so the second unit (20) may not be physically separated from the first unit (10) without damaging the first unit (10). For example, the sub-unit can also be separated from the first unit (10) along with the second unit (20).

[0092] In some embodiments, the second unit (20) and the second unit (20) can be physically separated from the first unit (10) at -30°C to -20°C.

[0093] In some embodiments, the second unit (20) and the second unit (20) can be physically separated from the first unit (10) at 40°C to 50°C.

[0094] In one embodiment, a gap is formed between the first unit (10) and the second unit (20) from which the replenishing electrolyte has been depleted, thereby separating the second unit (20) from which the replenishing electrolyte has been depleted and the sub-unit from the first unit (10). The replenishing electrolyte can be newly charged into the second unit (20) from which the replenishing electrolyte has been depleted and then reinserted into the first unit (10). However, in this case, the sealing line portion (178) can be reformed to maintain the sealing of the first space (172).

[0095] In one embodiment, a replacement unit (60) including a second unit (20') filled with a supplementary electrolyte and a sub-unit can be separately prepared and inserted into the first unit (10).

[0096] Referring to FIG. 9 (cell-case is briefly illustrated), a gap can be formed between the first unit (10) and the second unit (20) from which the replenishing electrolyte has been depleted. A replacement unit (60) can be inserted into the first unit (10) to separate the second unit (20) from which the replenishing electrolyte has been depleted by pushing it out of the first unit (10). The sub-unit can be separated from the first unit (10) together with the second unit (20). In this case, the replacement can be performed while maintaining the sealing of the first space (172).

[0097] In some embodiments, the replacement may be performed under low temperature conditions (e.g., -20°C or lower or -30°C or lower) or high temperature conditions (e.g., 40°C or higher or 50°C or higher). More preferably, the replacement may be performed under low temperature conditions. In this case, deterioration of the electrolyte under high temperature conditions can be prevented.

[0098] In some embodiments, the absolute value of the difference between the first coefficient of thermal expansion and the second coefficient of thermal expansion may be 5 μm / K or more, μm / K or more, or 20 μm / K or more. Within this range, the separation process can be carried out without degradation of the lithium secondary battery.

[0099] In some embodiments, the absolute value of the difference between the first coefficient of thermal expansion and the second coefficient of thermal expansion may be 50 μm / K or less, 40 μm / K or less, or 30 μm / K or less. Within this range, the sealing performance of the first space (172) can be improved. Within this range, external air and moisture can be effectively prevented from penetrating the first space (172) during the separation process.

[0100] Meanwhile, a high-temperature environment may be created in the lithium secondary battery due to heat generation during repeated charging and discharging. In some embodiments, the second thermal expansion coefficient may be greater than the first thermal expansion coefficient. In this case, a gap may be formed between the first unit (10) and the second unit (20) at low temperatures, and no gap may be formed at high temperatures. Accordingly, the high-temperature durability of the electrolyte storage unit (5) may be improved.

[0101] In some embodiments, the first unit (10) and the second unit (20) each may include metals such as stainless steel, copper, zinc, aluminum, manganese, tungsten, molybdenum, nickel, iron, silver, etc.; polymers such as EP (Engineering plastic), PET, etc.; and ceramics such as Al2O3, TiO2, etc. These may be used alone or in combination of two or more.

[0102] In some embodiments, the first unit (10) may include stainless steel, and the second unit (20) may include aluminum.

[0103] For example, the materials of the first unit (10), the second unit (20), and the sub-units may be materials that are chemically resistant to the supplemental electrolyte (for example, no adverse reactions occur with the supplemental electrolyte).

[0104] In some embodiments, the sub-unit may include metals such as stainless steel, copper, zinc, aluminum, manganese, tungsten, molybdenum, nickel, iron, silver, etc.; polymers such as EP (Engineering plastic), PET, etc.; and ceramics such as Al2O3, TiO2, etc. These may be used alone or in combination of two or more.

[0105] In some embodiments, the sub-unit may include stainless steel, aluminum, etc.

[0106] In some embodiments, the inner surface of the first body (12) and the outer surface of the second body (22) may each include a screw structure (16, 26) that can be fastened to each other. In this case, the sealing performance of the sealed space (50) can be further improved.

[0107] In some embodiments, the second space (174) may be formed on the side of the non-sealing portion (168). Accordingly, it is easy to insert the electrolyte storage unit (5) into the second space (174) in close contact, and durability against repeated detachment of the second unit (20) to the second sub-unit (40) can be ensured.

[0108] FIG. 10 is a cross-sectional view schematically showing an electrode assembly (150) according to exemplary embodiments.

[0109] For example, the electrode assembly (150) may include an anode (100) and a cathode (130) facing the anode (100).

[0110] For example, the positive electrode (100) may include a positive electrode current collector (105) and a positive electrode active material layer (110) on the positive electrode current collector (105).

[0111] For example, the positive active material layer (110) may include a positive active material, a positive binder and a conductive material as needed.

[0112] For example, the positive current collector (105) may include stainless steel, nickel, aluminum, titanium, copper, or an alloy thereof.

[0113] For example, the battery cell (1) may be a lithium secondary battery.

[0114] For example, the positive electrode active material may include a material capable of reversible insertion and extraction of lithium ions. For example, the positive electrode active material may include lithium metal oxide particles. For example, the positive electrode binder and the conductive material may be any materials known in the art without limitation.

[0115] For example, the cathode (130) may include a cathode current collector (125) and a cathode active material layer (120) on the cathode current collector (125).

[0116] For example, the negative electrode active material layer (120) may include a negative electrode active material, a negative electrode binder and a conductive material as needed.

[0117] For example, the negative current collector (125) may include gold, stainless steel, nickel, aluminum, titanium, copper, or an alloy thereof.

[0118] For example, the above-mentioned negative electrode active material may be a material capable of absorbing and extracting lithium ions. For example, the above-mentioned negative electrode active material may include a lithium alloy, a carbon-based active material, a silicon-based active material, etc. For example, the above-mentioned positive electrode binder and the above-mentioned conductive material may be any materials known in the art without limitation.

[0119] For example, a separator (140) may be interposed between the anode (100) and the cathode (130).

[0120] For example, the separator (140) may be any known in the field without limitation.

[0121] For example, an electrode assembly (150) can be formed by alternately and repeatedly stacking an anode (100), a cathode (130), and a separator (140). For example, the electrode assembly (150) can be formed by winding, laminating, zigzag-folding, etc. of the separator (140).

[0122] Referring to FIGS. 1 and 10, the battery cell (1) may include a positive lead (107) connected to a positive electrode (100) and protruding outside of a cell case (160); and a negative lead (127) connected to a negative electrode (130) and protruding outside of a cell case (160).

[0123] For example, the positive electrode (100) and the positive electrode lead (107) may be electrically connected. Likewise, the negative electrode (130) and the negative electrode lead (127) may be electrically connected.

[0124] For example, the positive lead (107) can be electrically connected to the positive current collector (105). Additionally, the negative lead (130) can be electrically connected to the negative current collector (125).

[0125] For example, the positive current collector (105) may include a positive tab (106) protruding from one side. A positive active material layer (110) may not be formed on the positive tab (106). The positive tab (106) may be integral with the positive current collector (105) or connected by welding or the like. The positive current collector (105) and the positive lead (107) may be electrically connected through the positive tab (106).

[0126] For example, the negative current collector (125) may include a negative tab (126) protruding from one side. A negative active material layer (120) may not be formed on the negative tab (126). The negative tab (126) may be integral with the negative current collector (125) or connected by welding or the like. The negative current collector (125) and the negative lead (127) may be electrically connected through the negative tab (126).

[0127] For example, the electrode assembly (150) may include a plurality of positive electrodes and a plurality of negative electrodes. For example, each of the plurality of positive electrodes may include a positive electrode tab. For example, each of the plurality of negative electrodes may include a negative electrode tab.

[0128] For example, the anode tabs (or cathode tabs) may be laminated, pressed, and welded to form an anode tab laminate (or cathode tab laminate). For example, the anode tab laminate may be electrically connected to an anode lead (107). For example, the cathode tab laminate may be electrically connected to a cathode lead (127).

[0129] For example, the above electrolyte and supplementary electrolyte may include a lithium salt, an organic solvent, and, if necessary, additives. For example, the lithium salt, organic solvent, and additives known in the art may be used without limitation.

[0130] battery module

[0131] Hereinafter, a battery module according to exemplary embodiments will be described in more detail with reference to the drawings. However, the drawings and embodiments are merely illustrative and the present invention is not limited thereto.

[0132] Referring to FIG. 11, a battery module (200) according to exemplary embodiments may include a cell stack (210), a module case (220), and a cooling unit (250).

[0133] For example, the cell stack (210) may include a plurality of the battery cells (1) described above. For example, the battery cells (1) may be stacked in a horizontal (or vertical) direction inside a module case (220) to form the cell stack (210).

[0134] The module case (220) can accommodate at least partially the cell stack (210). For example, the module case (220) may have a structure in which a U-shaped plate having a cross-sectional shape with one side open, for example, a U-shaped cross-section (in this specification, a U-shaped cross-section also includes a shape with angles at the corners), and a straight plate are combined to form a space inside. However, it is not limited thereto.

[0135] Referring to FIG. 11, the module case (220) has a U-shape consisting of an upper surface (221) and a side surface (222), and can accommodate the upper surface and both sides of the cell stack (210).

[0136] In some embodiments, a module case (220) and a straight plate may be interconnected through a side portion (222) on the lower side facing the upper portion (221). In this case, a cooling unit (25) may be connected to the upper portion (221) or the straight plate.

[0137] In some embodiments, the module case (220) and the cooling unit (250) can be coupled to each other through the side portion (222) on the lower side facing the upper portion (221).

[0138] In one embodiment, the battery module (200) may further include an insulating cover (230) and an end plate (240).

[0139] For example, the end plate (240) can be attached to the sides (i.e., the front and the rear) of the module case (220) other than the side portion (222).

[0140] Referring to FIG. 11, the end plate (240) can form the exterior of the battery module (200) together with the module case (220).

[0141] In one embodiment, the end plate (240) may have a through hole (242) for exposing the connection terminal (232) of the insulating cover (230) to the outside.

[0142] The end plate (240) can be attached to the module case (220) through a fastening member such as a screw or bolt.

[0143] Referring to FIG. 11, an insulating cover (230) may be interposed between the end plate (240) and the cell stack (210).

[0144] For example, an insulating cover (230) may be attached to one or both sides where the electrode leads (107, 127) of the battery cell (1) are positioned. For example, the electrode leads (107, 127) may penetrate the insulating cover (230) and be interconnected on the outside of the insulating cover (230). For example, the insulating cover (230) may include a connection terminal (232) for connecting the battery cell (1) to the outside. For example, the electrode leads (107, 127) may be electrically connected to the connection terminal (232) through circuit wiring (not shown) provided in the insulating cover (230). For example, the circuit wiring may connect the battery cells (1) in series / parallel through a bus bar (not shown).

[0145] Referring to FIG. 11, the connection terminal (232) can be exposed to the outside through a through hole (242) formed in the end plate (240). The through hole (242) of the end plate (240) can be formed with a size corresponding to the size and shape of the connection terminal (132).

[0146] For example, the insulating cover (230) may include a circuit board (e.g., a PCB) and a plurality of electronic components, such as a sensor mounted on the circuit board.

[0147] In one embodiment, a cooling unit (250) may be disposed on one side of the cell stack (210) to cool the cell stack (210).

[0148] In some embodiments, one side of the cell stack (210) may be in direct contact with the cooling unit (250).

[0149] In one embodiment, as shown in FIG. 12, the cooling unit (250) may include a cooling channel (251) through which a cooling fluid flows and a cooling plate (251). One side of the cell stack (210) may come into contact with the cooling plate (251).

[0150] In one embodiment, as shown in FIG. 12, the battery cells (1) may be arranged so that the electrolyte storage unit (5) is adjacent to the cooling unit (25).

[0151] For example, as shown in FIG. 12, battery cells (1) can be arranged such that an electrolyte storage unit (5) is placed between an electrode assembly (150) and a cooling unit (250) in the cross-sectional direction.

[0152] In one embodiment, the electrolyte storage unit (5) may include a flat area formed along the longitudinal direction of the electrolyte storage unit (5) on at least a portion of its outer surface. For example, among the outer surfaces of the electrolyte storage unit (5), the outer surface facing the cooling unit (250) may include a flat surface.

[0153] In some embodiments, the electrolyte storage unit (5) may have the shape of a polygonal column (in this specification, the polygonal column includes cases where the sides have curvature, provided that at least one side has a flat shape). In some embodiments, the electrolyte storage unit (5) may have the shape of a square column.

[0154] For example, if the cell case (160) is a pouch-type case, the electrolyte storage unit (5) can be inserted to contact the non-sealing portion (168) of the cell case (160). The non-sealing portion (168) may have a flat surface due to the flat outer surface of the electrolyte storage unit (5).

[0155] For example, as shown in FIG. 12, the outer surface facing the cooling unit (150) of the electrolyte storage unit (5) has a flat surface and can be in surface contact with the bottom surface of the cell case (160). Additionally, the bottom surface of the cell case (160) and the top surface of the cooling unit (250) can be in surface contact.

[0156] For example, in the case of a conventional pouch-type battery cell, the non-sealing portion may be concavely sunken during the folding process of the pouch case or the degassing process of the cell. Accordingly, the surface-contact efficiency between the battery cell and the cooling unit, and the cooling efficiency of the battery module may be reduced. On the other hand, in the battery cell (1) according to exemplary embodiments, the non-sealing portion (168) may have a flat surface due to the electrolyte storage unit (5). Accordingly, the surface-contact efficiency between the battery cell (1) and the cooling unit (250) may be increased, and the cooling efficiency of the battery module (200) may be further improved.

[0157] In some embodiments, as shown in FIG. 12, the surface of the electrode assembly (150) facing the electrolyte storage unit (5) may have a flat surface. Additionally, the outer surface of the electrolyte storage unit (5) facing the electrode assembly (150) may have a flat surface. Accordingly, the electrode assembly (150) and the electrolyte storage unit (5) may be in surface contact. Explanation of the symbols

[0158] 1: Battery cell 5: Electrolyte storage unit 10: 1st Unit 12: 1st Body 14: 1st hole 16, 26: Screw structure 20: 2nd Unit 22: 2nd Body 24: 2nd Hole 30: 1st Sub Unit 32: 1st tubular body 34: 1st sub-hole 36: 1st packing section 40: 2nd sub-unit 42: Second tubular body 44: Second sub-hole 46: Second packing section 50: Sealed space 60: Replacement Unit 100: Anode 105: Positive current collector 110: Positive active material layer 120: Cathode active material layer 125: Cathode current collector 130: Cathode 140: Separator 150: Electrode assembly 160: Cell case 162, 164, 166: Sealed section 168: Non-sealed section 172: 1st Space 174: 2nd Space 176: Passage section 178: Ceiling line section 200: Battery module 210: Cell stack 215: Cushion pad 220: Module case 221: Top surface 222: Side surface 230: Insulation cover 232: Connection terminal 240: End plate 242: Through hole 250: Cooling unit 251: Cooling plate 252: Cooling Euro

Claims

Claim 1 A battery module comprising: a cell stack including a plurality of battery cells; a module case that at least partially accommodates the cell stack; and a cooling unit disposed on one side of the cell stack; wherein each of the battery cells includes a cell case, an electrode assembly and an electrolyte accommodated within the cell case, and an electrolyte storage unit inserted into the cell case to supply a supplementary electrolyte and disposed between the electrode assembly and the cooling unit in a cross-sectional direction; wherein the electrolyte storage unit includes a first unit comprising a first body having a tubular hollow and first holes formed in the first body; and a second unit inserted into the hollow of the first body and comprising a second body having a tubular structure and second holes formed in the second body, wherein the first unit has a first coefficient of thermal expansion and the second unit has a second coefficient of thermal expansion greater than the first coefficient of thermal expansion. Claim 2 A battery module according to claim 1, wherein the outer surface of the electrolyte storage unit facing the cooling unit includes a flat surface. Claim 3 A battery module according to claim 2, wherein in the cross-sectional direction, the flat surface of the electrolyte storage unit and the bottom surface of the cell case are in surface contact, and the bottom surface of the cell case and the top surface of the cooling unit are in surface contact. Claim 4 A battery module according to claim 3, wherein the bottom surface of the cell case is a non-sealing surface. Claim 5 A battery module according to claim 1, wherein the electrolyte storage unit has the shape of a polygonal column. Claim 6 A battery module according to claim 1, wherein the longitudinal direction of the electrode assembly and the longitudinal direction of the electrolyte storage unit are parallel. Claim 7 A battery module according to claim 1, wherein the first body has the shape of a polygonal column, and the electrolyte storage unit comprises a tubular body and sub-holes formed in the tubular body, and further comprises a sub-unit inserted into the first unit such that the sub-holes are offset from the first holes. Claim 8 A battery module according to claim 7, wherein the second unit is inserted between the first unit and the sub-unit such that at least one of the second holes overlaps with at least one of the first holes. Claim 9 A battery module according to claim 7, wherein the sub-unit comprises a first sub-unit and a second sub-unit inserted into each of the two ends of the first unit. Claim 10 A battery module according to claim 8, wherein the second holes are arranged offset from the sub-holes. Claim 11 A battery module according to claim 8, wherein the inner surface of the first body and the outer surface of the second body each have a screw structure so as to be fastened to each other. Claim 12 delete Claim 13 In claim 8, the battery module, wherein at a temperature of -20°C or lower, the second unit is physically separable from the first unit. Claim 14 A battery module according to claim 9, wherein the first sub-unit and the second sub-unit are disposed within the first unit such that they are spaced apart from each other in the longitudinal direction of the first unit. Claim 15 A battery module according to claim 14, wherein the first sub-unit and the second sub-unit are movable by an external force in the longitudinal direction such that at least one of the sub-holes overlaps with at least one of the first holes. Claim 16 A battery module according to claim 14, wherein the electrolyte storage unit further comprises: a first packing portion coupled to one end of the first sub-unit; and a second packing portion coupled to one end of the second sub-unit. Claim 17 A battery module according to claim 1, wherein the cell case comprises: a first space for accommodating the electrode assembly and the electrolyte; a second space into which the electrolyte storage unit is inserted; and a passage portion through which the replenishing electrolyte can move between the first space and the second space. Claim 18 A battery module according to claim 17, wherein the passage portion includes a sealing line portion that can be opened by pressure from the discharge of the supplementary electrolyte.

Images