Battery module case with living hinge structure

Abstract

The present invention relates to a battery module case that is foldably assembled by having a living hinge applied to the battery module case in which an accommodation part accommodating a plurality of battery cells is formed, thereby reducing the number of work processes required for battery module assembly and simultaneously reducing the weight and reinforcing the strength of the battery module case, and to a battery module case with a living hinge structure, comprising: a pair of side covers supporting the surfaces on both sides of an accommodation part; and an upper cover disposed to cover the upper surface of the accommodation part, wherein the pair of side covers are integrally injection-molded such that each of the pair of side covers is foldably connected to the upper cover in the living hinge structure, and further comprising rhomboid-reinforced fibers capable of connecting and covering the entirety of the pair of side covers and the upper cover.

Description

Battery module case with living hinge structure

[0001] The present invention relates to a foldable battery module case having a living hinge structure, and more specifically, to a battery module case in which a plurality of cover members, which house and protect stacked battery cells inside and also perform an insulating function, are integrated into a foldable structure using a living hinge, and the living hinge and cover members are reinforced with reinforcing fibers and reinforcing ribs.

[0002] Secondary batteries, which repeatedly store and supply electric energy, are used not only in the field of small high-tech electronic devices such as mobile phones, PDAs, and laptop computers, but also as a power source for energy storage systems (ESS), electric vehicles (EVs, Electric Vehicles, Energy Storage Systems), and hybrid electric vehicles (HEVs, Hybrid Electric Vehicles).

[0003] Secondary batteries, which are currently widely used in storage systems (ESS) and electric vehicles (EV), can be classified into lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. These secondary batteries are repeatedly charged and discharged with an output voltage of approximately 25 V to 42 V per unit cell.

[0004] Therefore, when higher output voltage and power capacity are required, multiple battery cells are connected to form a battery module, or these battery modules are connected again in series or parallel and other circuits are added to form a high-output battery pack.

[0005] At this time, when a battery pack is configured using square or pouch-shaped battery cells that can be stacked with high integration and are lightweight relative to their capacity, a swelling phenomenon occurs in which the outer skin of the battery cell swells due to causes such as overcharging or overdischarging caused by repeated charging and discharging, leaving it at high temperatures, or external impact.

[0006] Additionally, if a localized short circuit of the internal electrodes within a battery cell occurs, for example due to contamination of the separator separating the electrodes by trapped foreign matter and / or mechanical action or damage, the strong short circuit current will heat the battery cell to temperatures of up to 800 °C, and sometimes up to 1300 °C, in a short period of time. This process is called thermal runaway, and such thermal runaway in one battery cell can easily and / or quickly spread to other adjacent battery cells. This is because the separator loses stability at relatively low temperatures, for example, above 120 °C, so that a short circuit can occur quickly in adjacent battery cells.

[0007] Since swelling and thermal runaway phenomena such as the above can lead to safety accidents such as fire and explosion as well as shortened lifespan, reduced capacity and reduced performance of secondary batteries, battery modules safely store stacked battery cells inside a battery module case to protect them from external impacts.

[0008] In addition, the battery module is additionally provided with a compression pad placed between the battery cells to accommodate swelling of the battery cells and support them under pressure, and a strap that fastens the mutually assembled cover members to prevent deformation or detachment of the battery module case due to the swollen battery cells.

[0009] For example, a conventional battery module is composed of a plurality of steel plate frames assembled in a box shape to prevent changes in the external shape of a battery module due to swelling or to reduce external impact, as shown in Patent Publication No. 10-2015-0142790 (publication date: December 23, 2015) entitled “End plate for battery module assembly capable of preventing changes in the external shape of a battery module due to swelling and a battery pack including the same” or FIG. 1.

[0010] However, these conventional battery modules have the problem of increasing the labor required to manufacture battery modules because they require an assembly process in which workers individually connect side straps and multiple upper straps to connect the first plate and the second plate, which support each side of the battery module assembly.

[0011] In addition, conventional battery modules are not only vulnerable to electrical insulation for battery modules that handle high voltages due to their structure being supported by steel plates, but also have concerns that the weight of the battery module may increase excessively. Therefore, structural improvements or modifications are needed, such as enhancing the strength of the battery module case without additionally placing high-strength steel plates on the cover.

[0012] Patent Publication No. 10-2015-0142790 (published on December 23, 2015)

[0013] The present invention, taking into account the above problems, aims to provide a foldable battery module case with a living hinge structure that reduces the weight and the labor required for assembling a battery module by integrating and simplifying a cover member that protects battery cells from external impact or swelling, and has improved strength.

[0014] A battery module case having a living hinge structure and having a storage portion in which a plurality of battery cells are stored inside of the present invention includes a pair of side covers supporting both sides of the storage portion and an upper cover arranged to cover an upper surface of the storage portion, wherein the pair of side covers are integrally injection-molded to be foldably connected to the upper cover by a living hinge structure, and further includes a ridged reinforcing fiber that can cover the entirety of the pair of side covers and the upper cover.

[0015] As one embodiment, the side cover and the upper cover of the battery module case of the present invention may be formed with reinforcing ribs extending in the longitudinal direction of the battery cells stored in the storage portion.

[0016] As one embodiment, the side cover of the battery module case of the present invention may be formed in an arc shape with the thickest central portion.

[0017] As another embodiment, the side cover of the battery module case of the present invention may be formed in an arc shape in which the thickness of the front, rear, and center is the same, and the central portion from the front to the center and from the center to the rear is the thickest.

[0018] The present invention comprises a pair of side covers for supporting both sides of a storage unit that stores a plurality of battery cells inside, and an upper cover arranged to cover the upper surface of the storage unit, which are foldably connected to each other with a living hinge structure and are integrally injection-molded with engineering plastic, thereby reducing the number of man-hours required for assembling a battery module and improving the efficiency of the assembly work. In addition, a ridged reinforcing fiber and reinforcing rib that can connect and cover the entire pair of side covers and the upper cover are arranged to extend the lifespan of the living hinge and reinforce its strength, and there is an effect of simultaneously reducing the weight of the battery module case and reinforcing its strength.

[0019] Figure 1 is an exploded view of a battery module case according to the prior art.

[0020] FIG. 2 is a plan view of an upper cover and a side cover integrally injection-molded in a foldable battery module case having a living hinge structure according to an embodiment of the present invention.

[0021] Figure 3 is a cross-sectional view taken along the cutting line AA of Figure 2.

[0022] FIG. 4 is a cross-sectional view taken along the cutting line AA of FIG. 2 as another embodiment of the present invention.

[0023] FIG. 5 is a cross-sectional view taken along the cutting line AA of FIG. 2 as another embodiment of the present invention.

[0024] The terms used in this application are used only to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0025] In this application, the terms “include” or “have” are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0026] In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

[0027]

[0028] Hereinafter, preferred embodiments for achieving the purpose of the present invention will be described with reference to the drawings attached to the present invention.

[0029] FIG. 2 is a plan view of an upper cover and a side cover integrally injection-molded in a foldable battery module case having a living hinge structure according to an embodiment of the present invention, FIG. 3 is a cross-sectional view taken along the cutting line AA of FIG. 2, FIG. 4 is a cross-sectional view taken along the cutting line AA of FIG. 2 according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along the cutting line AA of FIG. 2 according to yet another embodiment of the present invention.

[0030]

[0031] A battery module case having a foldable cover structure according to an embodiment of the present invention is an invention that reduces the work required for assembling a battery module by integrating side covers (2a, 2b) and an upper cover (4) by integrally injection-molding them with engineering plastic, and at the same time, includes a radial reinforcing fiber (9) and a reinforcing rib (10) that can connect and cover the entire pair of side covers (2a, 2b) and the upper cover (4), thereby reinforcing the strength of the battery module case.

[0032] In order to specifically implement the function or action as described above, a battery module case having a foldable cover structure according to the present invention, as shown in FIGS. 1 and 2, includes a battery storage section, side covers (2a, 2b) and an upper cover (4) that are integrated through a living hinge (8) to store the battery inside, and a ridged reinforcing fiber (9) and a reinforcing rib (10) that can connect and cover the entire pair of side covers (2a, 2b) and the upper cover (4), and may be configured in an embodiment in which an upper clamp (3) is added to the upper side of the upper cover (4), and an embodiment in which an upper clamp (3) is not added.

[0033]

[0034] Below, each of the above-described components will be described in detail.

[0035] First, the battery compartment is where a plurality of pouch-shaped (wide plate-shaped) battery cells are stacked and stored so that their wide surfaces are stacked in the transverse direction (X-axis direction) to form a predetermined output voltage and power.

[0036] In such a battery compartment, a buffer pad (not shown) made of a material such as polyurethane may be interposed between the battery cells to prevent changes in appearance due to the swelling phenomenon described above and to protect the battery cells from external impact.

[0037] Here, the battery cell may be formed by including a positive electrode plate and a negative electrode plate in an electrolyte, a film that surrounds and seals the electrolyte, the positive electrode plate and the negative electrode plate, and a lead tab, which is a protruding plate-shaped electrode that electrically connects the positive electrode plate and the negative electrode plate to an external bus bar, respectively.

[0038] At this time, the lead tabs may be formed on the front and rear sides of the battery cell, or, unlike the drawing, may be formed together on either the front or rear sides.

[0039] The battery storage section as described above is merely a part configured to allow for stacking of battery cells that are already known and commercialized in the horizontal direction (X-axis direction), and is unrelated to the gist of the present invention, so a detailed description of its structure and operating characteristics will be omitted.

[0040] The battery module case is a hexahedral component having an internal space that protects the battery compartment described above from external impact or changing external environment, and may be configured to include a pair of side covers (2a, 2b), an upper cover (4), a lower cover (7), a front cover (5), and a rear cover (6), as shown in FIG. 1.

[0041] First, the front and rear covers (5, 6) are arranged to support the front and rear sides of the storage compartment where the battery cells are stored, respectively, and are members that enable charging and discharging of the battery storage compartment. They form the front and rear sides of the battery module case, respectively, and a fixing groove into which a plurality of stacked battery cells are inserted can be formed, and a mounting groove into which a bus bar is mounted and fixed can be formed on the surface opposite to the fixing groove.

[0042] The front and rear covers (5, 6) described above can be combined with the lower cover (7) in a living hinge (8) structure, and thus can be implemented in the same manner as the pair of side covers (2a, 2b) and the upper cover (4) described in the present invention are combined in a living hinge (8) structure, and since there is only a difference in the combining members, a detailed description of the structure and operating characteristics thereof will be omitted.

[0043] Next, the lower cover (7) is a plate-shaped member that supports the lower part of the storage section where the battery cells are stored and supports the overall weight of the battery cells. It is formed of a material having sufficient strength to support the above-mentioned weight, or a reinforcing rib (10) may be added to reinforce the strength, and is connected or fitted with a pair of side covers (2a, 2b) and front / rear covers (5, 6) by various fastening means such as bolts.

[0044] The upper cover (4) is a plate-shaped member for protecting the upper part of the storage section where the battery cells are stored, and is integrally injection-molded to be connected to a pair of side covers (2a, 2b) to be described later on both sides in the stacking direction of the battery cells by a living hinge (8) structure.

[0045] A living hinge (8) is also called an integral hinge, and is a thin, flexible hinge made of the same material as the two solid parts, and is formed thinner than other cover members so that the solid piece can be bent along the line of the hinge, and polyethylene (PE) and polypropylene (PP) with excellent fluidity and fatigue resistance are preferred, and acrylonitrile butadiene styrene (ABS) may also be used.

[0046] Meanwhile, the side covers (2a, 2b) are plate-shaped members that support both sides of the battery compartment where swelling occurs in the direction in which the battery cells are stacked (X-axis direction) and also perform an electrical insulation function for the battery compartment. These side covers (2a, 2b) are formed by being connected to the upper cover (4) with a living hinge (8) structure and are joined or fitted to the lower cover (7) and the front and rear covers (5, 6) by various fastening means such as bolts to form both sides of the battery module case.

[0047] The side covers (2a, 2b) according to the embodiment of the present invention are configured with a structure in which a ridged reinforcing fiber (9) is inserted into the interior of engineering plastic, as shown in FIGS. 2 to 5, so as to suppress the swelling phenomenon and reinforce the strength of the living hinge (8), and further, reinforcing ribs (10) are formed in the side covers (2a, 2b).

[0048] Engineering plastics can be made of PPS, TPI, PES, PPA, PEI, etc., which have excellent insulation, heat resistance, rigidity, and flame retardancy, and reinforcing fibers (9) can be made of materials with greater strength than engineering plastics, such as glass fibers and carbon fibers.

[0049] The side covers (2a, 2b) above are integrally formed with a living hinge (8) for connection with the upper cover (4). However, the living hinge (8) is thin to perform its function as a hinge and thus has weaker strength than other cover members. To compensate for this, a ridged reinforcing fiber (9) is inserted that can extend from one side cover (2a) of the pair of side covers (2a, 2b) through the upper cover (4) to the other side cover (2b).

[0050] As in this embodiment, when the ridged reinforcing fiber (9) is formed to extend from one side cover (2a) of a pair of side covers (2a, 2b) through the upper cover (4) to the other side cover (2b), it can stably support the stress applied to the battery module case when the battery expands while the battery cells repeat charging and discharging, and can also supplement the weakness of the strength of the living hinge (8). That is, when the battery cells expand, displacement accumulates in the stacking direction of the battery cells, so that a very large stress is applied, which may cause damage to the living hinge connecting the battery module case or the upper cover (4) and the pair of side covers (2a, 2b), but according to this embodiment, the ridged reinforcing fiber (9) stably reinforces and supports this, thereby protecting the battery module case.

[0051] However, since the above-mentioned ridged reinforcing fiber (9) can provide great resistance to tensile stress but cannot exert great resistance to compressive stress, a reinforcing means may be required. That is, when a swelling phenomenon occurs in the battery cell housed in the battery module case and the side covers (2a, 2b) are about to bulge while expanding in the stacking direction of the battery cells (X-axis direction), the ridged reinforcing fiber (9) receives tensile stress in the stacking direction of the battery cells (X-axis direction) and compressive stress in the longitudinal direction of the battery cells (Y-axis direction). At this time, since the ridged reinforcing fiber (9) cannot adequately resist the shrinkage stress, the strength to resist the swelling phenomenon may be weakened.

[0052] Therefore, to compensate for this, reinforcing ribs (10) can be formed in the longitudinal direction (Y-axis direction) of the battery cell in the upper cover (4) and side covers (2a, 2b) so as to be able to receive shrinkage stress in the longitudinal direction (Y-axis direction) of the battery cell.

[0053] When the reinforcing rib (10) is formed as above, the shrinkage stress that the ridge-shaped reinforcing fiber (9) receives in the longitudinal direction of the battery cell can be compensated for by the resistance of the reinforcing rib (10), thereby coping with the swelling phenomenon that occurs in the battery cell.

[0054]

[0055] Meanwhile, the side covers (2a, 2b) can be formed in an arc shape with the thickest center portion (11) in the Y-axis direction when viewed from above, as shown in Fig. 4, so that the side covers (2a, 2b) can protect the storage portion where the battery cells are stored while resisting the swelling phenomenon with the strength of the side covers (2a, 2b) alone, even without installing a separate upper clamp (3) on the upper cover (4).

[0056] That is, when the side covers (2a, 2b) are assembled and joined in a state in which they are restrained by the front and rear covers (5, 6) arranged in the longitudinal direction (Y-axis direction) of the battery cell by means of a connecting means such as bolts with the lower cover (7) and the front and rear covers (5, 6), and when swelling occurs in the battery cell during use, stress is concentrated in the central portion (11) of the side covers (2a, 2b).

[0057] Therefore, the central part (11) of the side covers (2a, 2b) will be the most vulnerable part, so that the central part (11) of the side covers (2a, 2b) in the Y-axis direction can be formed in an arc shape to be the thickest part to compensate for this.

[0058]

[0059] As another embodiment of the present invention, an upper clamp (3) may be added to the upper cover (4) of the battery module case to improve safety against swelling.

[0060] At this time, the side covers (2a, 2b) are assembled in a state where they are restrained by the front and rear covers (5, 6) arranged in the longitudinal direction of the battery cell by means of connecting means such as bolts with the lower cover (7) and the front and rear covers (5, 6), and the center is restrained by the upper clamp (3). Therefore, when a swelling phenomenon occurs in the battery cell during use, stress is concentrated in the central portions (11a, b) from the joint portion of the side covers (2a, 2b) and the front cover (5) to the center, and from the center to the side covers (2a, 2b) and the rear cover (6). Therefore, in order to compensate for this, as shown in FIG. 5, the central portion (11a) from the joint portion of the side covers (2a, 2b) and the front cover (5) to the center, and also the central portion (11b) from the center to the side covers (2a, 2b) and the rear cover (6) are connected in an arc shape so that they are thicker than other portions. Can be formed.

[0061] The battery module case according to the above embodiment has the same structure as the battery module case according to the embodiment without the upper clamp (3), except that the upper clamp (3) is added to the upper cover (4) of the battery module case, so a duplicate description of the same structure is omitted.

[0062]

[0063] According to the present embodiment formed as described above, durability against external impact is improved. In particular, when the battery is applied to an electric vehicle or electric scooter, if a traffic accident occurs and an external impact is applied, the battery module case may be damaged. If the battery module case is damaged, there is a risk of fire or electric shock due to a short circuit. However, according to the present embodiment, the ridged reinforcing fiber (9) and reinforcing rib (10) absorb the impact, thereby enhancing the strength of the battery module case, thereby improving the safety of the battery.

[0064] In addition, since the strength of the battery module case is improved relative to its thickness, it is possible to reduce the thickness of the battery module case while maintaining an appropriate strength, thereby reducing the weight of the battery.

[0065]

[0066] Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom, and therefore the true technical scope of the present invention should be determined by the technical idea of ​​the appended claims.

[0067] 1: End plate 2a. 2b: Side cover

[0068] 3: Upper clamp 4: Upper cover

[0069] 5: Front cover 6: Back cover

[0070] 7: Lower cover 8: Living hinge

[0071] 9: Reinforcing fiber 10: Reinforcing rib

[0072] 11, 11a, 11b: Central part in the Y-axis direction

Claims

1. A battery module case having a storage compartment formed therein in which multiple battery cells are stored, The battery module case includes a pair of side covers supporting both sides of the storage unit; and an upper cover arranged to cover the upper surface of the storage unit. The above pair of side covers are integrally injection-molded so that they can be foldably connected to each other with the upper cover using a living hinge structure, respectively. A battery module case having a living hinge structure characterized by including a ridged reinforcing fiber that can cover the entire pair of side covers and upper covers by connecting them.

2. In claim 1, The side cover and top cover of the above battery module case are, A battery module case having a living hinge structure characterized by further including a reinforcing rib extending in the longitudinal direction of the battery cells stored in the above storage unit.

3. In claim 2, The above side cover is a battery module case with a living hinge structure characterized by being formed in an arc shape with the thickest central thickness.

4. In claim 2, The above side cover is a battery module case with a living hinge structure characterized by having the same thickness at the front, rear, and center, and being formed in an arc shape with the thickest central portion from the front to the center and from the center to the rear.

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