KR20080087193A - Battery pack guaranteeing safety at electrolyte leakage - Google Patents

Abstract

A battery pack is provided to ensure the safety against leakage of an electrolyte and to maintain improved binding strength, while simplifying the battery pack assemblage process. A battery pack comprises at least one unit cells received between an upper casing(100) and a lower casing(200). The battery pack further comprises a leakage-preventing wall(300) between the upper casing and the lower casing to prevent an electrolyte leaked from the cells from being introduced into a predetermined portion. The leakage-preventing wall comprises a sidewall member(102,202) protruding out from the upper casing and/or lower casing, and a sealing member(302) mounted via an assembling step so that the sealing member surrounds at least the end of the sidewall member to accomplish sealing. The sealing member is formed of an elastic material.

Description

Battery Pack Guaranteed Safety at Electrolyte Leakage {Battery Pack Guaranteed Safety at Electrolyte Leakage}

1 is a schematic cross-sectional view of a battery pack case having a leakproof wall formed according to the prior art;

2 is a schematic cross-sectional view of a battery pack having a leakage preventing wall according to an embodiment of the present invention;

3 is a schematic cross-sectional view of a battery pack having a leakage preventing wall according to another embodiment of the present invention;

4 is a schematic diagram of a structure in which the sealing member included in the leakage preventing wall of FIG. 3 is bonded to the upper case and assembled.

The present invention relates to a battery pack which is guaranteed safety when the electrolyte leaks, and more particularly, in a battery pack in which one or more battery cells are embedded between the upper case and the lower case, the electrolyte leaking from the battery cell is A leakage preventing wall is formed between an upper case and a lower case which can prevent the flow into a predetermined portion, and the leakage preventing wall includes a side wall member protruding from an upper and / or lower case, and at least an end of the side wall member. It relates to a battery pack comprising a sealing member of the elastic material that is mounted in an assembly manner so as to achieve a sealing while wrapping.

As technology development and demand for mobile devices increase, the demand for batteries as energy sources is rapidly increasing, and accordingly, many studies on batteries that can meet various demands have been conducted.

Representatively, there is a high demand for rectangular secondary batteries and pouch secondary batteries, which can be applied to products such as mobile phones with a thin thickness in terms of shape of batteries, and lithium ion batteries with high energy density, discharge voltage, and output stability in terms of materials. There is a high demand for lithium secondary batteries such as lithium ion polymer batteries.

In addition, secondary batteries are classified according to the structure of the electrode assembly having a cathode / separation membrane / cathode structure. Representatively, a jelly having a structure in which long sheet-shaped anodes and cathodes are wound with a separator interposed therebetween -Roll (electrode) electrode assembly, a stack (stacked type) electrode assembly in which a plurality of positive and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator, and the positive and negative electrodes of a predetermined unit are interposed through a separator And a stacked / folding electrode assembly having a structure in which a bi-cell or full cells stacked in a state are wound.

Recently, a pouch-type battery having a structure in which a stacked or stacked / folding electrode assembly is incorporated into a pouch-type battery case of an aluminum laminate sheet has attracted much attention due to its low manufacturing cost, low weight, and easy shape deformation. And its usage is gradually increasing.

However, lithium secondary batteries have a problem in that they are fundamentally low in safety. In particular, the pouch-type battery is used in the form of a battery pack embedded in the pack case to compensate for the low mechanical rigidity of the battery case, but when the heat sealing seal is separated, a flammable material such as electrolyte leaks, which poses a high risk of fire. Have.

On the other hand, one of the main causes of abnormal operation of the secondary battery is a case where an electrical short is caused. Therefore, the secondary battery is equipped with various safety devices such as a fuse and a protection circuit. However, when the electrolyte of the battery cell leaks, the leaked electrolyte may flow into the protection circuit unit or the like, which may cause malfunction, short circuit, and fire of the protection circuit. Therefore, in order to prevent causing such a problem, it may be desirable to form a leakage preventing wall inside the pack case.

1 is a cross-sectional view schematically showing a battery pack case in which a leakproof wall is formed in the prior art.

Referring to FIG. 1, the battery pack case 50 has a structure in which the upper case 10 and the lower case 20 are coupled to each other, and each sidewall member protruding from the upper case 10 and the lower case 20. The fields 12 and 22 overlap each other to form a leakage preventing wall 30 to isolate a portion (a) on which the battery cell is mounted and a portion (b) on which the protection circuit is mounted.

However, since the leakage preventing wall 30 has a structure in which the side wall members 12 and 22 are in contact with each other, there is a minute gap in the contact portion. The electrolyte leaked from the battery cell (not shown) in the part (a) may flow into the part (b) through this minute gap.

When the two sidewall members 12 and 22 are configured to closely contact each other in order to eliminate such minute gaps, they are easily broken due to the structural limitations of the thin sidewall members 12 and 22, and also due to vibration and external force. The side wall members 12 and 22 may be spaced apart.

As a technique for solving this problem, Japanese Patent Application Laid-Open No. 2003-297317 discloses that when the upper and lower cases are coupled, the partition walls and the separation grooves formed in the respective cases are coupled to each other to protect the battery cell accommodating portion. Disclosed is a battery pack structure in which a circuit part is isolated and a resin is filled between a separation groove and a separation wall. However, the above technique suffers from problems such as poor structural stability against external forces such as distortion and vibration, and difficulty in work processes due to complex structures.

Therefore, there is a high need for a battery pack case that is easy to assemble and has sufficient mechanical rigidity and can secure safety even when an electrolyte leaks from a battery cell.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

The inventors of the present application, after in-depth study and various experiments, can improve the assembly process of the leakage preventing wall formed between the upper case and the lower case of the battery pack, greatly simplifying the assembly process, and leakage of the electrolyte. It has been confirmed that the advantages of maintaining the bond strength while at the same time ensuring the safety, and to complete the present invention.

Accordingly, the battery pack according to the present invention is a battery pack in which one or more battery cells are built between an upper case and a lower case, and has an upper portion capable of preventing an electrolyte leaking from the battery cell from entering a predetermined portion. A leakage preventing wall is formed between the case and the lower case, and the leakage preventing wall is mounted in an assembly manner so as to enclose a side wall member protruding from the upper and / or lower case and at least an end of the side wall member. It consists of a sealing member, the sealing member is made of an elastic material.

That is, in the battery pack according to the present invention, an electrolyte leaking from the battery cell is introduced into the protection circuit part of the battery pack even by a simple assembling process by a sealing member having elasticity that is sealed by surrounding the end of the sidewall member in the leakage preventing wall. It can be prevented and excellent in structural stability against external forces such as warping and vibration, thereby greatly improving the safety of the battery.

The sealing member is not particularly limited as long as it is made of a material having chemical resistance to the electrolyte and durability and elasticity. For example, rubber, silicone, elastic synthetic resin, or the like may be used. The sealing member is in close contact with the side wall member by the elastic force to prevent leakage of the electrolyte.

In general, secondary batteries contain various combustible materials, and thus, there is a risk of overheating and explosion due to overcharge, overcurrent, and other physical external shocks. Therefore, a lithium secondary battery has a protection circuit that can effectively control abnormal conditions such as overcharge. The module PCM is mounted in a state connected to the battery cell. If electrolyte flows into these protection circuit modules, there is a risk of heat generation and explosion due to short circuit and malfunction.

Therefore, in the present invention, the predetermined portion is preferably a portion where the protective circuit module is located, and even if the electrolyte leaks from the battery cell is isolated from the protective circuit module by the leakage preventing wall, it is possible to greatly improve the safety.

The structure of the leakage preventing wall may vary, and as one preferred example, a first sidewall member protruding from the upper case and a second sidewall member protruding from the lower case in a state spaced apart from an end of the first sidewall member. And it may be a structure consisting of a sealing member having an H-type structure in the vertical cross-section so as to surround the end of the first side wall member and the end of the second side wall member at the same time.

The sealing member is in close contact with an end portion of each side wall member and a predetermined portion on both sides, such a structure is inserted into the upper side of the sealing member of the H-shaped structure, the lower side or the upper side of the side wall member protruding from the upper or lower case It can be achieved by inserting the side wall portion protruding from the case to the lower portion of the sealing member.

In another preferred embodiment, the leakage preventing wall may be a structure consisting of a side wall member protruding from the upper or lower case, and a sealing member attached to the lower or upper case while surrounding at least an end of the side wall member. The side wall member protruding from the upper or lower case forms a spaced portion at a predetermined interval in the lower or upper case, and the sealing member is attached to the corresponding portion of the lower or upper case while elastically surrounding the end of the side wall member. The spacing site can be sealed by this.

The sealing member is attached to the lower or upper case may be various, for example, it is possible to be bonded by an adhesive, a combination by a mechanical fastening structure and the like. Specifically, a structure may be formed in which a sidewall member protruding from an upper or lower case and a sealing member bonded by an adhesive to a corresponding portion of the lower or upper case corresponding to the sidewall member are formed to form a leakage preventing wall. have.

On the other hand, the pouch-type battery in which the electrode assembly is built in the battery case of the laminate sheet including the resin layer and the metal layer has a low mechanical rigidity, has a high risk of internal short circuit due to external impact, and a heat-sealed sealing part is separated. It has a disadvantage of high risk of leaking ignition materials such as electrolyte. In addition, the leakage of the internal short circuit and the flammable material may lead to ignition or explosion, such a pouch-type battery cell may be preferably used as the battery cell accommodated in the battery pack according to the present invention.

The battery pack according to the present invention may be preferably applied to a medium to large battery module of high output and large capacity. Therefore, the present invention provides a medium-large battery module including the battery pack. Since the structure of the medium-large battery module and its manufacturing method are well known in the art, a description thereof will be omitted herein.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

2 is a cross-sectional view schematically showing a battery pack having a leakage preventing wall according to an embodiment of the present invention.

2, the battery pack has a structure in which the upper case 100 and the lower case 200 are coupled to each other, and the first sidewall member 102 and the lower case 200 protruding from the upper case 100. A leakproof wall made of a protruding second sidewall member 202 and an elastic sealing member 302 having an H-shaped structure in a vertical cross section surrounding end portions of both sidewall members 102 and 202 and portions of both side surfaces thereof. It consists of a structure including 300).

The leakage preventing wall 300 isolates the battery cell mounting part (a) and the protection circuit part (b), one or more battery cells are mounted in the battery cell mounting part (a), and the overload of the battery cell is provided in the protection circuit part (b). A protection circuit module (PCM) is mounted to protect the battery pack from the risk of over-discharge, heat generation and short circuit (for convenience of description, the battery cell and the protection circuit module are not shown).

The leaktight prevention wall 300 including the elastic sealing member 302 of the H-type structure has structural stability from external forces such as distortion and vibration, and closes and covers the end surfaces of the sidewall members 102 and 202 and a part of both sides. By the structure, the electrolyte leaked from the battery cell is prevented from entering the protective circuit portion (b).

3 is a cross-sectional view schematically showing a battery pack having a leakage preventing wall according to another embodiment of the present invention.

Referring to FIG. 3, the leakage preventing wall 310 of the battery pack is sealed in close contact with the upper case 100 while surrounding the side wall member 204 protruding from the lower case 200 and the end of the side wall member 204. The member 312 is comprised. Although the side wall member 204 protruding from the lower case 200 forms a spaced portion at a predetermined interval with respect to the upper case 100, the side wall member 204 is formed by a sealing member 312 which is elastically coupled while wrapping its end. Since the separation part is blocked, the battery cell mounting part (a) and the protection circuit part (b) are isolated.

While the sealing member is closely attached to the upper case in FIG. 3, FIG. 4 schematically illustrates a structure in which the sealing member included in the leakage preventing wall of FIG. 3 is bonded and assembled to the upper case.

Referring to FIG. 4, the leakage preventing wall 320 is attached to the side wall member 204 protruding from the lower case 200 and a corresponding portion of the upper case 100 corresponding to the side wall member 204 by an adhesive. The sealing member 314 is coupled to each other to form a leakage preventing wall 320, to isolate the battery cell mounting portion (a) and the protection circuit portion (b).

Although described above with reference to the drawings according to an embodiment of the present invention, those skilled in the art will be able to perform a variety of applications and modifications within the scope of the present invention based on the above contents.

As described above, the battery pack according to the present invention improves the structural stability significantly by improving the structure of the leakage preventing wall formed between the battery pack case, can simplify the assembly process, and the safety against electrolyte leakage By improving, there is an effect that can ultimately greatly improve the performance and life of the battery.

Claims (7)

In a battery pack in which one or more battery cells are built between an upper case and a lower case, a leakage preventing wall between an upper case and a lower case which may prevent an electrolyte leaking from a battery cell from entering a predetermined portion. The leakage preventing wall is formed of a side wall member protruding from the upper and / or lower case, and a sealing member is mounted in an assembly manner so as to form a seal while wrapping at least an end of the side wall member, the sealing Battery pack, characterized in that the member is made of an elastic material. The battery pack as claimed in claim 1, wherein the predetermined part is a part where the protection circuit module is located. The liquid leakage preventing wall of claim 1, wherein the leakage preventing wall comprises: a first side wall member protruding from the upper case, a second side wall member protruding from the lower case in a state spaced apart from an end of the first side wall member, and the first side wall. A battery pack comprising a sealing member having an H-shaped structure in a vertical cross section so as to simultaneously wrap an end of a member and an end of a second side wall member. The battery pack as claimed in claim 1, wherein the leakage preventing wall comprises a sidewall member protruding from the upper or lower case, and a sealing member that is in close contact with the lower or upper case while surrounding at least an end of the sidewall member. The battery pack as claimed in claim 4, wherein the sealing member has a structure in which the sealing member is bonded to a corresponding portion of the case corresponding to the protruding side wall member. The battery pack according to claim 1, wherein the battery cell is a battery in which an electrode assembly is embedded in a laminate sheet including a metal layer and a resin layer. A medium to large battery module of a high output large capacity comprising the battery pack according to any one of claims 1 to 6.

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