KR102658636B1 - Battery module case with living hinge - Google Patents

Abstract

The present invention reduces the number of working hours required for assembling a battery module, reduces the weight of the battery module case and enhances its strength at the same time, by applying a living hinge to a battery module case with a storage portion where a plurality of battery cells are stored inside, and assembling it in a foldable manner. It relates to a battery module case configured to enable the battery module case to include 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, wherein the pair of side covers each cover the upper part. Regarding a battery module case with a living hinge structure that is integrally injection molded to be foldable and connected to each other with a cover and living hinge structure, and also includes rhomboid reinforcing fibers that can connect and cover a pair of side covers and the entire top cover. will be.

Description

Battery module case with living hinge structure {Battery module case with living hinge}

The present invention relates to a foldable battery module case with a living hinge structure, and more specifically, to integrating the stacked battery cells into a foldable structure using a living hinge on a plurality of cover members that store and protect the stacked battery cells inside and also perform an insulating function. The present invention relates to a battery module case in which the living hinge and cover member are reinforced with reinforcing fibers and reinforcing ribs.

Secondary batteries, which repeatedly store and supply electrical energy, have gone beyond the field of small, high-tech electronic devices such as mobile phones, PDAs, and laptop computers, and have recently been used in energy storage systems (ESS), electric vehicles (EVs), and energy storage systems (ESS) and electric vehicles (EVs). It is used as a power source for a storage system or a hybrid vehicle (HEV, Hybrid Electric Vehicle).

Currently, secondary batteries widely used in storage systems (ESS) or electric vehicles (EV) can be classified into lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. Car batteries are repeatedly charged and discharged at an output voltage of approximately 25V to 42V per unit cell.

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

At this time, when a battery pack is constructed using prismatic or pouch-type battery cells that can be stacked with a high degree of integration and are lightweight compared to capacity, they are susceptible to overcharging or overdischarging due to repeated charging and discharging, leaving at high temperatures, external shock, etc. The same cause causes a swelling phenomenon, in which the outer shell of the battery cell swells.

Additionally, if a local short-circuit of the internal electrodes occurs within the battery cell, for example due to trapped foreign matter and/or contamination of the separator separating the electrodes by mechanical action or damage, a strong short-circuit current can reach up to 800 °C in a short period of time. The battery cells are heated up to, sometimes up to 1300 °C. This process is called thermal runaway, and thermal runaway from 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 short circuits can quickly occur in adjacent battery cells.

Since the above swelling and thermal runaway phenomena can not only shorten the lifespan of the secondary battery, reduce its capacity, and reduce its performance, but also lead to safety accidents such as ignition and explosion, the battery module places the stacked battery cells inside the battery module case. It is stored safely and protected from external shocks.

In addition, the battery module includes a compression pad disposed between the battery cells to accommodate swelling of the battery cell and support the battery cell, and a cover member assembled together to prevent deformation or separation of the battery module case due to the swollen battery cell. Additional fastening straps, etc. are provided.

For example, a conventional battery module is described in Patent Publication No. 10-2015-0142790 (publication date: December 23, 2015), 'An end plate for a battery module assembly that can prevent changes in the appearance of the battery module due to the swelling phenomenon, and As shown in FIG. 1, the battery pack including this is composed of a plurality of steel plate frames assembled in a box shape to prevent changes in the appearance of the battery module due to swelling or to reduce external shock.

However, these conventional battery modules require an assembly process in which an operator individually joins the side straps and a plurality of upper straps in order to connect the first plate and the second plate, which respectively support both sides of the battery module assembly, to each other. There is a problem of increased man-hours in production.

In addition, the conventional battery module has a structure supported by steel plates, so not only is it vulnerable to electrical insulation for battery modules that handle high voltage, but there is also a risk that the weight of the battery module will increase excessively, so a high-tensile steel plate must be additionally placed on the cover. There is a need for structural improvements or improvements, such as improving the strength of the battery module case.

Public Patent Publication No. 10-2015-0142790

In consideration of the above-mentioned problems, the present invention integrates and simplifies the cover member that protects the battery cells from external shock or swelling, thereby reducing the weight and at the same time reducing the man-hours required for assembling the battery module, and a foldable living hinge structure with improved strength. The purpose is to provide a battery module case.

The battery module case of the present invention has a living hinge structure with a storage portion in which a plurality of battery cells are stored inside, a pair of side covers supporting both sides of the storage portion, and an upper cover disposed to cover the upper surface of the storage portion. Including, wherein the pair of side covers are integrally injection molded to be foldable and connected to each other with the upper cover and the living hinge structure, respectively, and a rhomboid shape that can connect and cover the entire pair of side covers and the upper cover. Contains reinforcing fibers.

As an example, reinforcing ribs extending in the longitudinal direction of the battery cells stored in the storage unit may be formed on the side cover and top cover of the battery module case of the present invention.

As an example, the side cover of the battery module case of the present invention may be formed in an arc shape with the thickest central portion.

As another example, 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 are the same, and the thickness of the central portion from the front to the middle and from the middle to the rear is the thickest.

In the present invention, a pair of side covers supporting both sides of a storage unit that stores a plurality of battery cells inside, and an upper cover disposed to cover the upper surface of the storage unit are foldable and connected to each other through a living hinge structure. As it is integrally injection-molded with plastic, the work time required to assemble the battery module can be reduced, thereby improving the efficiency of the assembly work, and the rhomboid reinforcing fibers and reinforcing ribs that can connect and cover the entire pair of side covers and the upper cover are provided. By being arranged, the lifespan and strength of the living hinge can be extended and the strength of the battery module case can be lightened and strengthened at the same time.

1 is an exploded view of a battery module case according to the prior art.
Figure 2 is a plan view of a top cover and a side cover that are integrally injection-molded in a foldable battery module case with a living hinge structure according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along line AA of FIG. 2.
Figure 4 is a cross-sectional view taken along the cutting line AA of Figure 2 as another embodiment of the present invention.
Figure 5 is a cross-sectional view taken along the cutting line AA of Figure 2 as another embodiment of the present invention.

The terms used in this application are merely used to describe specific embodiments, etc., and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates a different meaning.

In this application, terms such as "comprise" or "have" are intended to refer to the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features or numbers. It should be understood that the presence or addition of steps, operations, components, parts or combinations thereof is not excluded in advance.

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.

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

Figure 2 is a plan view of a top cover and a side cover that are integrally injection-molded in a foldable battery module case with a living hinge structure according to an embodiment of the present invention, Figure 3 is a cross-sectional view taken along the cutting line A-A of Figure 2, and Figure 4 is a As another embodiment of the present invention, it is a cross-sectional view taken along the cutting line A-A of FIG. 2, and FIG. 5 is a cross-sectional view taken along the cutting line A-A of FIG. 2 as another embodiment of the present invention.

The battery module case with a foldable cover structure according to an embodiment of the present invention integrates the side covers (2a, 2b) and the top cover (4) by injection molding with engineering plastic, thereby reducing the work time required for battery module assembly. Meanwhile, the strength of the battery module case is increased by including rhomboid reinforcing fibers (9) and reinforcing ribs (10) that can connect and cover the entire pair of side covers (2a, 2b) and the upper cover (4). It is an invention designed to strengthen.

In order to specifically implement the above-described functions and operations, the battery module case having a foldable cover structure according to the present invention includes a battery compartment and a side surface to accommodate the battery compartment inside, as shown in FIGS. 1 and 2. The covers (2a, 2b) and the upper cover (4) are integrated through the living hinge (8), while the pair of side covers (2a, 2b) and the upper cover (4) are connected and covered as a whole. Rhomboid reinforcing fiber (9) and a reinforcing rib 10, and may be composed of an embodiment in which the upper clamp 3 is added to the upper side of the upper cover 4, and an embodiment in which the upper clamp 3 is not added.

Hereinafter, each of the above-described configurations will be described in detail.

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

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

Here, the battery cell includes positive and negative plates in the electrolyte, a film that surrounds and seals the electrolyte, positive and negative plates, and lead tabs, which are protruding plate-shaped electrodes that electrically connect the positive and negative plates to the external bus bar, respectively. It can be done.

At this time, the lead tabs may be formed on the front and rear of the battery cell, respectively, or, unlike shown, may be formed together on either the front or the rear.

The battery compartment as described above is merely a part configured to stack already known and commercialized battery cells in the horizontal direction (X-axis direction), and is unrelated to the gist of the present invention, so no detailed information about its structure or operating characteristics is required. The explanation will be omitted.

The battery module case is a hexahedral-shaped component with an internal space that protects the battery compartment from external shocks or changing external environments. As shown in FIG. 1, it includes a pair of side covers 2a and 2b. , it may be composed of an upper cover (4), a lower cover (7), a front cover (5), and a rear cover (6).

First, the front and rear covers 5 and 6 are members that are arranged to support the front and back of the compartment where the battery cells are stored, respectively, and allow charging and discharging of the battery compartment, and are located on the front and back of the battery module case. may be formed, and a fixing groove into which a plurality of stacked battery cells are inserted may be formed, and a seating groove into which a bus bar is mounted and fixed may be formed on the surface opposite to the fixing groove.

Since the front and rear covers 5 and 6 can be combined with the lower cover 7 and the living hinge 8 structure, a pair of side covers 2a and 2b and an upper cover to be described in the present invention. (4) can be implemented in the same way as combining the living hinge (8) structure, and the only difference is the coupling member, so detailed descriptions of the structure and operating characteristics, etc. will be omitted.

Next, the lower cover 7 is a plate-shaped member that supports the lower part of the storage part where the battery cells are stored and supports the entire weight of the battery cells, and is made of a material strong enough to support the above-mentioned weight, or is reinforced with strength. For this purpose, a reinforcing rib 10 can be added, and the pair of side covers 2a, 2b and the front and rear covers 5, 6 are coupled or fitted by various fastening means such as bolts.

The upper cover (4) is a plate-shaped member to protect the upper part of the compartment where the battery cells are stored, and is composed of a pair of side covers (2a, 2b), which will be described later, and a living hinge (8) on both sides in the stacking direction of the battery cells. It is injection molded as one piece to form a connection.

The living hinge (8), also called an integrated hinge, is a thin and flexible hinge made of the same material as the two solid parts. It is formed thinner than other cover members to allow bending of the solid piece along the line of the hinge, and has fluidity and fatigue resistance. These excellent polyethylene (PE) and polypropylene (PP) are preferred, and acrylonitrile butadiene styrene (ABS) may also be used.

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. As such, these side covers (2a, 2b) are connected to the upper cover (4) and the living hinge (8) structure and are connected to the lower cover (7) and the front and rear covers (5, 6) and various fastening means such as bolts, etc. They are joined or fitted to form both sides of the battery module case.

The side covers (2a, 2b) according to an embodiment of the present invention are made of engineering plastic (as shown in FIGS. 2 to 5) to suppress swelling and simultaneously reinforce the strength of the living hinge (8). It has a structure in which rhomboid reinforcing fibers (9) are inserted into the interior of engineering plastic, and reinforcing ribs (10) are formed on the side covers (2a, 2b).

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

The side covers (2a, 2b) are integrally formed with a living hinge (8) for connection with the upper cover (4). The living hinge (8) is thinner than other cover members to perform the function as a hinge. Since the strength is weak, in order to compensate for this, the ridge reinforcement can be extended from the side cover (2a) on one side of the pair of side covers (2a, 2b) through the upper cover (4) to the side cover (2b) on the other side. Fiber 9 is inserted.

As in this embodiment, when the rhomboid reinforcing fibers (9) are 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), When the battery expands while the battery cell repeats charging and discharging, it can not only stably support the stress applied to the battery module case, but also compensate for the weakness in the strength of the living hinge 8. In other words, when the battery cells expand, displacement accumulates in the stacking direction of the battery cells, so a very large stress is applied, causing damage to the battery module case or the living hinge connecting the upper cover (4) and the pair of side covers (2a, 2b). However, according to this embodiment, the rhomboid reinforcing fibers 9 stably reinforce and support it to protect the battery module case.

However, the rhomboid reinforcing fibers 9 can provide great resistance to tensile stress, but cannot provide great resistance to compressive stress, so reinforcing means may be necessary. That is, if a swelling phenomenon occurs in the battery cell stored in the battery module case and the side covers 2a, 2b bulge as the battery cells expand in the stacking direction (X-axis direction), the rhomboid reinforcing fibers 9 will It receives tensile stress in the stacking direction (X-axis direction) and compressive stress in the longitudinal direction of the battery cell (Y-axis direction). At this time, the rhomboid reinforcing fibers (9) cannot properly resist the shrinkage stress, so they resist swelling. Your strength may weaken.

Therefore, in order to compensate for this, the top cover 4 and the side covers 2a and 2b are reinforced in the longitudinal direction of the battery cell (Y-axis direction) to withstand the shrinkage stress in the longitudinal direction (Y-axis direction) of the battery cell. A rib 10 may be formed.

When the reinforcing ribs 10 are formed as described above, the resistance of the reinforcing ribs 10 can compensate for the shrinkage stress experienced by the rhomboided reinforcing fibers 9 in the longitudinal direction of the battery cell, thereby preventing the swelling phenomenon that occurs in the battery cell. You will be able to cope with it.

Meanwhile, the side covers (2a, 2b) resist swelling due to the strength of the side covers (2a, 2b) even if a separate upper clamp (3) is not installed on the upper cover (4) and form a storage portion where the battery cells are stored. For protection, as shown in FIG. 4, the central portion 11 in the Y-axis direction may be formed in an arc shape with the thickest thickness when viewed from the top.

That is, the side covers 2a and 2b are disposed in the longitudinal direction (Y-axis direction) of the battery cell by connecting means such as bolts with the lower cover 7 and the front and rear covers 5 and 6. If swelling occurs in the battery cell during use after being assembled and constrained by the rear covers 5 and 6, stress is concentrated in the central portion 11 of the side covers 2a and 2b.

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

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 phenomenon.

At this time, the side covers (2a, 2b) are connected to the lower cover (7) and the front and rear covers (5, 6) by connecting means such as bolts to the front and rear covers (5, 6) arranged in the longitudinal direction of the battery cell. ) and is assembled with the center restricted by the upper clamp (3), so if swelling occurs in the battery cell during use, the side covers (2a, 2b) and the front cover (5) Since the stress is concentrated in each central part (11a, b) from the coupling part to the center, and from the center to the side covers (2a, 2b) and the rear cover (6), to compensate for this, shown in Figure 5 As shown, the central portion (11a) from the joining portion of the side covers (2a, 2b) and the front cover (5) to the center, and the central portion (11a) from the center to the side covers (2a, 2b) and the rear cover (6) 11b) can be connected in an arc shape so that the thickness is thicker than other parts.

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. Therefore, duplicate descriptions of the same structure are omitted.

According to the present embodiment formed as above, durability against shock transmitted from the outside is improved. In particular, when the battery is applied to an electric vehicle or electric scooter, a traffic accident may occur and the battery module case may be damaged if an external shock is transmitted. If the battery module case is damaged, there is a risk of fire or electric shock due to a short circuit. However, according to this embodiment, the rhomboid reinforcing fibers 9 and the reinforcing ribs 10 absorb shock, thereby improving the strength of the battery module case, thereby improving the safety of the battery.

In addition, since the strength of the battery module case is improved compared to the thickness, the thickness of the battery module case can be reduced while maintaining appropriate strength, which has the effect of reducing the weight of the battery.

The present invention has been described with reference to the embodiments shown in the drawings, but these are illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. The true technical scope should be determined by the technical spirit of the attached patent claims.

1: End plate 2a. 2b: Side cover
3: Top clamp 4: Top cover
5: Front cover 6: Rear cover
7: Lower cover 8: Living hinge
9: Rhomboid reinforcing fiber 10: Reinforcing rib
11, 11a, 11b: Central part in Y-axis direction

Claims (4)

A battery module case having a storage portion in which a plurality of 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 disposed to cover the upper surface of the storage unit,
The pair of side covers are integrally injection molded to be foldable and connected to each other with the upper cover and a living hinge structure, respectively,
It also includes rhomboid reinforcing fibers that can connect and cover the entire pair of side covers and the upper cover,
The side cover and top cover of the battery module case are,
A battery module case with a living hinge structure further comprising reinforcing ribs extending in the longitudinal direction of the battery cells stored in the storage unit.
delete In claim 1,
The side cover is a battery module case with a living hinge structure, characterized in that the side cover is formed in an arc shape with the thickest central portion.
In claim 1,
The side cover has the same thickness at the front, rear, and center, and is formed in an arc shape with the thickest central portion from the front to the middle and from the middle to the rear.