Patent Description:
In general, a secondary battery means a battery capable of charge/discharge, unlike a primary battery that may not be charged, and is widely used in electronic devices such as mobile phones, laptop computers, camcorders, and the like, or electric vehicles. In particular, since a lithium secondary battery has a larger capacity than a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic equipment, and has a high energy density per unit weight, the degree of utilization thereof is rapidly increasing.

When a secondary battery is overcharged or a sudden change occurs in the electrical environment, an electrolyte may be decomposed at the positive electrode and lithium metal may be deposited at the negative electrode, and in the case of occurrence of such phenomenon, the performance of the secondary battery may be downgraded. In addition, a secondary battery uses, for example, a solvent such as ethylene carbonate or propylene carbonate as an electrolyte, but these solvents are decomposed at a high temperature to generate gas, and thus it causes an increase in pressure, whereby a swelling phenomenon that is a kind of inflating phenomenon may occur, resulting in serious problems such as explosion of the secondary battery.

Accordingly, the present applicant is seeking a method of removing the risk factor of the secondary battery by inducing gas venting in a specific direction before the internal pressure of the secondary battery increases to reach an explosion risk stage.

For example, Korean Patent Publication No. <CIT> discloses a cylindrical secondary battery in which an electrode assembly and an electrolyte are placed in a metal can and sealed with a top cap, and a gas hole is applied to the top cap. When a thermal runaway situation occurs, the cylindrical secondary battery is configured such that gas inside the metal can is discharged to the outside through the gas hole of the top cap so as not to increase the internal pressure.

However, the pouch-type secondary battery <NUM> may not structurally apply a gas hole as in a cylindrical or prismatic secondary battery, and as shown in <FIG>, it is formed of a structure in which the electrode assembly <NUM> is disposed between the upper pouch sheet <NUM> and the lower pouch sheet <NUM> and then four edges of the upper and lower pouch sheets <NUM>, <NUM> are thermally fused to be sealed, whereby it is not easy to induce gas venting in a specific direction. Accordingly, it is required to develop a gas venting means suitable for a pouch-type secondary battery.

The document <CIT> relates to a battery pack having gas discharge pipe.

The document <CIT> relates to an electrical storage device and electrical storage device module.

The document <CIT> relates to a secondary battery and battery pack using the same.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to reducing a risk factor by venting gas in a specific direction during swelling of a pouch-type secondary battery.

Other objects and advantages of the present disclosure will be described below, and will be learned by embodiments of the present disclosure. In addition, the objects and advantages of the present invention is realized by configurations and a combination of configurations falling within the scope of the appended claims.

According to the present invention, there is provided a gas venting induction block according to claim <NUM> including a block body having a slit to allow the cell terrace of a pouch-type secondary battery to be inserted to a predetermined depth; a pocket portion provided inside the block body and provided to accommodate a portion of the cell terrace in a form in which a space is expanded larger than the slit; and an exhaust pipe provided in a tubular shape and extending from the pocket portion to the outer surface of the block body, wherein the exhaust pipe includes a needle portion protruding sharply toward the inner space of the pocket portion so as to perforate the cell terrace when the cell terrace expands beyond a certain volume in the pocket portion.

The block body may include a block upper portion and a block lower portion spaced apart vertically with the slit therebetween; and a block front portion having no slit and connected to the block upper portion and the block lower portion.

The block upper portion and the block lower portion may be vertically symmetrical, and the thickness of the middle region may be configured to be thinner than the thickness of both edge regions so that the pocket portion is provided.

One end of the exhaust pipe corresponding to the needle portion may be located in the pocket portion and the other end of the exhaust pipe may be exposed to the outside of the block front portion via the inside of the block front portion.

The exhaust pipe is plural and may include an upper exhaust pipe having the needle portion protruding from the block upper portion toward the pocket portion; and a lower exhaust pipe having the needle portion protruding from the block lower portion toward the pocket portion.

The gas venting induction block may include a cell lead outlet having a size corresponding to the width and thickness of the electrode lead of the pouch-type secondary battery and provided to penetrate the block front portion to communicate with the pocket portion.

The gas venting induction block may include two foam members disposed in the pocket portion and spaced apart vertically with the slit therebetween.

The needle portion may be configured to be positioned within the foam member.

According to another aspect, there may be provided a pouch-type secondary battery including the above-described gas venting induction block.

According to still another aspect, there may be provided a battery module including the above-described pouch-type secondary batteries.

The gas venting induction block according to claim <NUM> is capable of suppressing an increase in internal pressure of the secondary battery by venting gas during swelling of the pouch-type secondary battery. In particular, internal gas may be ejected in a specific direction through the gas venting induction block during swelling of the secondary battery, thereby reducing a risk factor due to gas venting.

Advantageous effects to be obtained by the present disclosure are not limited to the above-described effects, and other effects not mentioned herein may be clearly understood by those skilled in the art from the following description of the present disclosure.

Prior to the description, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer description. Accordingly, the size or proportion of each component does not fully reflect the actual size or proportion.

Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the present disclosure, so it should be understood that other equivalents and modifications could be made thereto without departing from the scope of the appended claims.

<FIG> is a plan view of a pouch-type secondary battery according to an embodiment of the present disclosure, and <FIG> is a perspective view illustrating a portion of a pouch-type secondary battery according to an embodiment of the present disclosure.

The pouch-type secondary battery <NUM> according to an embodiment of the present disclosure may be configured to include an electrode assembly, an electrode lead <NUM>, a pouch case, and a gas venting induction block <NUM>.

The electrode assembly may include a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate may be formed by applying a positive electrode active material to a current collector plate made of aluminum (Al), and the negative electrode plate may be formed by applying a negative electrode active material to a current collector plate made of copper (Cu). The electrode assembly may be provided in a stack type formed by interposing a separator between the positive electrode plate and the negative electrode plate, or a jelly-roll type in which one positive electrode plate and one negative electrode plate are wound with a separator interposed therebetween. Of course, the scope of the present disclosure should not be limited thereto. For example, the electrode assembly may be provided in a stack-and-folding type in which a stack type and a jelly-roll type are mixed.

The electrode lead <NUM> is a portion that is connected to the electrode assembly and extends to the outside of the pouch case, and may function as an electrode terminal capable of being electrically connected to other secondary batteries or external devices. The electrode lead <NUM> includes a positive electrode lead connected to the positive electrode plate and a negative electrode lead connected to the negative electrode plate, and the positive electrode lead and the negative electrode lead may be positioned in different directions as in the present embodiment or attached to the electrode assembly to be positioned in the same direction unlike the present embodiment.

The pouch case may form a sealed space capable of accommodating and protecting the electrode assembly, the electrolyte, and the like, and may perform a heat dissipation function.

Although not shown in detail for convenience of drawings, the pouch case may be composed of an upper pouch sheet and a lower pouch sheet in the form of two laminate sheets. The upper and lower pouch sheets may include an outer insulating layer and an inner adhesive layer made of a polymer material, and a metal layer interposed between the outer insulating layer and the inner adhesive layer. Here, aluminum (Al) may be used as a material for the metal layer.

At least one of the upper pouch sheet and the lower pouch sheet may be provided to have a concavely formed space to accommodate the electrode assembly. For example, the electrode assembly may be disposed in a formed space of the lower pouch sheet, and the upper pouch sheet may be overlapped on the lower pouch sheet. In addition, a sealing portion <NUM> may be formed along the edge lines of the four sides of the upper and lower pouch sheets. Here, the sealing portion <NUM> may be defined as a portion in which the upper and lower pouch sheets are sealed by thermal fusion or the like.

Hereinafter, the portions of the sealing portion <NUM> where the electrode leads <NUM> protrude will be defined as cell terraces <NUM>, <NUM>, and the portions without the electrode leads <NUM> will be defined as side wings <NUM>, <NUM>. That is, in the pouch case, the sealing portion <NUM> on the short side corresponds to the cell terrace <NUM> and the sealing portion <NUM> on the long side corresponds to the side wings <NUM>, <NUM>. In addition, the portion surrounding the electrode assembly as an inner region based on the sealing portion <NUM> will be defined as the electrode accommodating portion <NUM>. Folding the side wings <NUM>, <NUM> and adhering to the side surface of the electrode accommodating portion may be advantageous in reducing the width of the secondary battery.

The gas venting induction block <NUM> is a component that serves to reduce risk factors by making a hole in the expanded sealing portion <NUM> and allowing gas to be ejected in a specific direction when the pressure increases to reach a dangerous level due to gas generation of the pouch-type secondary battery <NUM>.

Hereinafter, the configuration of the gas venting induction block <NUM> will be described in detail with reference to <FIG>.

The gas venting induction block <NUM> according to an embodiment of the present disclosure includes a block body <NUM>, a pocket portion <NUM>, an exhaust pipe <NUM>, and two foam members <NUM>, <NUM>.

As shown in <FIG>, the gas venting induction block <NUM> may be configured such that the electrode lead <NUM> passes through the block body <NUM> and the cell terrace <NUM> is inserted into the block body <NUM> to a predetermined depth.

In general, in the case of the pouch-type secondary battery <NUM>, when the internal pressure increases, the sealing of the cell terraces <NUM>, <NUM> in which the electrode leads <NUM> are located is destroyed rather than the side wings <NUM>, <NUM>, and thus the corresponding area tends to swell. For this reason, in order to actively discharge gas from the cell terraces <NUM>, <NUM> to the outside in an emergency, the present embodiment is configured to allow the gas venting induction block <NUM> to be inserted into the cell terrace <NUM> based on the electrode lead <NUM>. Of course, unlike the present embodiment, the gas venting induction block <NUM> may be inserted into the side wings <NUM>, <NUM> of the pouch-type secondary battery <NUM>, and in this case, the cell lead outlet O for withdrawing the electrode lead <NUM> may be omitted. A detailed description of the cell lead outlet O will be described later.

Specifically, the block body <NUM> constituting the gas venting induction block <NUM> is made of an insulating material such as plastic, and may be provided in a substantially rectangular parallelepiped shape as shown in <FIG>. Of course, the material of the block body <NUM> need not be necessarily limited to plastic. For example, the block body <NUM> may be made of ceramic or the like as an insulating material.

The thickness (Z-axis direction) of the block body <NUM> may correspond to the thickness of the pouch-type battery cell, the left-right length (±X-axis direction) of the block body <NUM> may be shorter than the length from one end to the other end of the cell terrace <NUM>, and the front-rear length of the block body <NUM> may be longer than the protruding length (-Y-axis direction) of the cell terrace <NUM> and shorter than the protruding length of the electrode lead <NUM>.

The block body <NUM> includes a slit S formed in a direction crossing the thickness direction so that the cell terrace <NUM> may be inserted into the inside. The slit S is formed by the protruding length of the cell terrace <NUM> from the rear of the block body <NUM> toward the front. By such a slit S, the block body <NUM> may be provided in a form in which the rear portion is bisected up and down.

Accordingly, the block body <NUM> includes a block upper portion 131a and a block lower portion 131b spaced vertically with the slit S therebetween, and a block front portion 131c connecting the block upper portion 131a and the block lower portion 131b as a portion without the slit S and having the cell lead outlet O through which the electrode lead <NUM> may be withdrawn.

The pocket portion <NUM> is a portion provided to have a space expanded larger than the slit S inside the block body <NUM> so that the cell terrace <NUM> may expand inside the block body <NUM> when gas is generated in the pouch-type secondary battery <NUM>.

For example, referring to <FIG> and <FIG>, since the block upper portion 131a and the block lower portion 131b are vertically symmetrical and the thickness of the middle region is smaller than the thickness of both edge regions, the pocket portion <NUM> expanded larger than the slit S may be provided between the block upper portion 131a and the block lower portion 131b.

The cell lead outlet O may be provided penetrating the block front portion 131c in a size corresponding to the width and thickness of the electrode lead <NUM> as shown in <FIG> and may be provided to communicate with the pocket portion <NUM> (in the Y-axis direction) inside the block body <NUM> as shown in <FIG>.

According to the above configuration, as shown in <FIG>, the cell terrace <NUM> may be inserted into a portion where the slit S is formed in the block body <NUM>, that is, between the block upper portion 131a and the block lower portion 131b, and the electrode lead <NUM> may be withdrawn to the outside of the block front portion 131c through the cell lead outlet O. A portion of the cell terrace <NUM> may be accommodated in the pocket portion <NUM> and the remaining portion may be exposed to the outside of both side surfaces of the block body <NUM>. In addition, both edge portions of the cell terrace <NUM> may be folded together with the side wings <NUM>, <NUM> to be in close contact with the side surface of the electrode accommodating portion <NUM>.

As described above, the exhaust pipe <NUM> may be provided in a tubular shape as a component for making a hole in the cell terrace <NUM> when the cell terrace <NUM> accommodated in the pocket portion <NUM> expands and directing the gas ejected from the cell terrace <NUM> in a specific direction, and may be configured to extend from the pocket portion <NUM> to the outer surface of the block body <NUM>.

For example, as shown in <FIG>, the exhaust pipe <NUM> may be configured such that one end is located in the pocket portion <NUM> and the other end P is exposed to the outside of the block front portion 131c via the inside of the block front portion 131c.

In addition, the exhaust pipe <NUM> may include a needle portion <NUM> protruding sharply toward the inner space of the pocket portion <NUM> so that the cell terrace <NUM> may be perforated when the cell terrace <NUM> expands beyond a certain volume in the pocket portion <NUM>.

The gas venting induction block <NUM> of the present embodiment has a plurality of exhaust pipes <NUM>, and the plurality of exhaust pipes <NUM> include two upper exhaust pipes 133a having needle portions <NUM> protruding downward from the block upper portion 131a toward the pocket portion <NUM> and two lower exhaust pipes 133b having needle portions <NUM> protruding upward from the block lower portion 131b toward the pocket portion <NUM>.

The two upper exhaust pipes 133a may be configured to be provided one by one in the left-right direction (±X-axis direction) based on the cell lead outlet O and to be exposed to the outside of the block front portion 131c via the inside of the block upper portion 131a and the block front portion 131c, respectively. In addition, the two lower exhaust pipes 133b may be configured to be provided one by one in the left-right direction (±X-axis direction) based on the cell lead outlet O and to be exposed to the outside of the block front portion 131c via the inside of the block lower portion 131b and the block front portion 131c, respectively.

The above-described exhaust pipe <NUM> may be made of a metal material such as stainless and may be integrally manufactured with the block body <NUM> by an insert injection molding method. However, the scope of the present disclosure is not limited to the material of the exhaust pipe <NUM> or the manufacturing method. For example, the exhaust pipe <NUM> may be made of the same material as the block body <NUM> and may be injection molded in a form integrated with the block body <NUM>.

Meanwhile, the gas venting induction block <NUM> according to the present embodiment may further include two form members disposed in the pocket portion <NUM> and vertically spaced apart with the slit S therebetween.

When the electrode lead <NUM> and the cell terrace <NUM> are inserted into the block body <NUM>, the electrode lead <NUM> or the cell terrace <NUM> may be in contact with the needle portion <NUM> to be damaged. The two foam members <NUM>, <NUM> are components for preventing the electrode lead <NUM> or the cell terrace <NUM> from being damaged unexpectedly in this way.

The two foam members <NUM>, <NUM> may be made of an elastic material such as sponge or memory foam, and as shown in <FIG>, with the slit S interposed therebetween in the pocket portion <NUM>, one may be attached to the inner surface of block upper portion 131a and the other may be attached to the inner surface of the block lower portion 131b.

For example, after pushing the foam members <NUM>, <NUM> into the pocket portion <NUM> (in the Y-axis direction) in a compressed state, the foam members <NUM>, <NUM> are adhered in an upward direction (+Z-axis direction) toward the inner surface of the block upper portion 131a or in a downward direction (-Z-axis direction) toward the inner surface of the block lower portion 131b so that the needle portion <NUM> is inserted into the foam members <NUM>, <NUM>. Thereafter, compression of the foam members <NUM>, <NUM> is released so that the foam members <NUM>, <NUM> are restored to their original volume. In this case, since the needle portions <NUM> are embedded in the foam members <NUM>, <NUM>, the foam members <NUM>, <NUM> may be held in contact with the inner surface of the block upper portion 131a or the inner surface of the block lower portion 131b. Here, the vertical distance between the two foam members <NUM> and <NUM> is at least greater than the slit S, and the needle portion <NUM> may be configured to be positioned in a state of being embedded in the foam members <NUM>, <NUM>.

Therefore, in the process of pushing the electrode lead <NUM> and the cell terrace <NUM> into the pocket portion <NUM>, there is no fear of damage to the electrode lead <NUM> or the cell terrace <NUM>. In this way, when gas is generated in the pouch-type secondary battery <NUM> in a state where the cell terrace <NUM> is positioned in the pocket portion <NUM> and the cell terrace <NUM> expands, the foam members <NUM>, <NUM> may be compressed by pressure. Furthermore, when the cell terrace <NUM> reaches a state expanded above a certain volume, a hole may be made by the needle portion <NUM>.

As the foam members <NUM>, <NUM>, foam members <NUM>, <NUM> having different degrees of compressibility, such as ethylene vinyl acetate (EVA) foam, synthetic latex, polystyrene foam (Styrofoam), sponge, and the like may be selectively used. For example, by changing the material of the foam members <NUM>, <NUM> as described above, the needle portion <NUM> and the cell terrace <NUM> may contact each other only when the expansion force of the cell terrace <NUM> is higher than a certain level, and thus gas may be discharged.

<FIG> is a cross-sectional view of the gas venting induction block <NUM> region when a pouch-type secondary battery <NUM> of the present disclosure is in normal, and <FIG> is a cross-sectional view of the gas venting induction block <NUM> region when a pouch-type secondary battery <NUM> of the present disclosure is swelling.

Referring to <FIG>, a gas discharge mechanism of the pouch-type secondary battery <NUM> by the gas venting induction block <NUM> will be briefly described as follows.

As shown in <FIG>, the electrode lead <NUM> passes through the gas venting induction block <NUM> and is withdrawn in the -Y-axis direction, and the cell terrace <NUM> may be inserted into the gas venting induction block <NUM> so that a portion thereof is accommodated in the pocket portion <NUM> of the block body <NUM>. Normally, the cell terrace <NUM> is spaced apart from the needle portion <NUM> by a predetermined distance and is blocked by the two foam members <NUM>, <NUM> in the vertical direction even if it moves somewhat due to external shock or vibration, so it is not in contact with the needle portion <NUM>.

However, when the internal pressure of the pouch-type secondary battery <NUM> increases due to gas generation, the cell terrace <NUM> may swell and the foam members <NUM>, <NUM> may be compressed. Furthermore, when the expansion of the cell terrace <NUM> intensifies and the degree of expansion reaches a certain volume or more, the needle portion <NUM> of the exhaust pipe <NUM> may make a hole in the cell terrace <NUM> and be inserted into the cell terrace <NUM> as shown in <FIG>. As a result, the gas in the cell terrace <NUM> may flow into the inside of the needle portion <NUM> and move along the inside of the exhaust pipe <NUM> to be ejected to the outside of the block front portion 131c.

According to this configuration of the present embodiment, when gas is generated in the pouch-type secondary battery <NUM> due to a situation such as thermal runaway, the internal pressure may be lowered by discharging the gas to the outside before the secondary battery reaches an explosion stage due to an increase in internal pressure, thereby preventing the secondary battery from exploding.

In addition, when gas is generated, the sealing portion <NUM> of the pouch case is damaged in an unspecified manner, thereby preventing the gas from being ejected in an unspecified direction. That is, in the present embodiment, since gas is discharged in a specific direction by the gas venting induction block <NUM>, the gas discharge location may be fully expected, thereby reducing risk factors due to gas discharge.

For example, as in this embodiment, by ejecting gas in the direction of the electrode lead <NUM> of the pouch-type secondary battery <NUM>, it may be easy to collect the gas ejected from each pouch-type secondary battery <NUM> when manufacturing the battery module, and the application of an exhaust system configuration for safely discharging the collected gas to the outside may be facilitated.

Next, with reference to <FIG>, a battery module according to an embodiment of the present disclosure including the above-described pouch-type secondary batteries <NUM> will be briefly described.

<FIG> is a view illustrating a portion of a battery module according to an embodiment of the present disclosure.

The battery module according to an embodiment of the present disclosure shown in <FIG> may be configured in a form in which the above-described pouch-type secondary batteries <NUM> are vertically erected and stacked in the left-right direction. In the case of a battery module composed of pouch-type secondary batteries according to the prior art, a plurality of bus bars made of metal materials such as copper are used as a component for electrically connecting the pouch-type secondary batteries, and a bus bar frame in the form of a plate body is included to support the plurality of bus bars. However, the battery module according to the present disclosure may be configured to omit the bus bar frame, assemble the gas venting induction blocks <NUM> of the pouch-type secondary battery <NUM> in one direction in an adhesive or snap-fit coupling method, and mount the bus bars <NUM> on the block front portion 131c of the gas venting induction block <NUM>.

For example, although not shown in the above-described embodiment, when a region of the block front portion 131c of each gas venting induction block <NUM> is processed and two gas venting induction blocks <NUM> are combined as shown in <FIG>, the gas venting induction block <NUM> may be configured to form a bus bar groove in which one bus bar <NUM> may be partially inserted and fixed. In this case, the pouch-type secondary batteries <NUM> may be electrically connected by bending and welding the positive electrode lead of one pouch-type secondary battery <NUM> and the negative electrode lead of the other pouch-type secondary battery <NUM> on one bus bar attached across the two gas venting induction blocks <NUM>.

Although not shown, the battery module of the present disclosure may be configured to safely discharge gas generated in the secondary batteries out of the battery module by adding holes through which gas is discharged from the gas venting induction blocks <NUM>, that is, a gas pipe (not shown) that may be connected to the other ends of the exhaust pipe <NUM>. Here, the gas pipe may be implemented in the form of a manifold having a plurality of intake ports and a single exhaust port.

In addition, the battery module of the present disclosure may be configured to further include various devices (not shown) for controlling charge/discharge of the pouch-type secondary batteries <NUM>, for example, a battery management system (BMS), a current sensor, a fuse, and the like, and a module housing for accommodating the pouch-type secondary batteries <NUM> and the various devices.

Claim 1:
A gas venting induction block (<NUM>) comprising:
a block body (<NUM>) having a slit (S) to allow the cell terrace (<NUM>) of a pouch-type secondary battery (<NUM>) to be inserted to a predetermined depth;
a pocket portion (<NUM>) provided inside the block body (<NUM>) and provided to accommodate a portion of the cell terrace (<NUM>) in a form in which a space is expanded larger than the slit (S); and
an exhaust pipe (<NUM>) provided in a tubular shape and extending from the pocket portion (<NUM>) to the outer surface of the block body (<NUM>),
wherein the exhaust pipe (<NUM>) comprises a needle portion (<NUM>) protruding sharply toward the inner space of the pocket portion (<NUM>) so as to perforate the cell terrace (<NUM>) when the cell terrace (<NUM>) expands beyond a certain volume in the pocket portion (<NUM>).