Battery module assembly and manufacturing method therefor

Abstract

A battery module assembly, according to one embodiment of the present invention, comprises: a battery module including a base substrate and at least one battery cell, wherein a plurality of unit battery modules formed to surround a cell cover are stacked on the base substrate; and a battery case which is coupled to the base substrate, and which includes a first case surrounding the front surface of the battery module and a second case combined with the first case and surrounding a rear surface of the battery module. The present invention can effectively provide coupling reliability with an inner sensing membrane which is coupled to the battery module, and can seal the inside of the battery case by tightly combining the first case and the second case in a lateral direction.

Claims

1. A battery module assembly, comprising: a base substrate with a coupling portion formed on an outer circumferential surface of the base substrate; a battery module that includes a plurality of unit battery modules which is stacked on the base substrate, each unit battery module including one or more battery cells and being covered by a cell cover; a battery case that is combined with the coupling portion of the base substrate and includes a first case and a second case combined with each other, the first case covering a rear surface portion of the battery module, the second case covering a front surface portion of the battery module, and the first case and the second case combined with the base substrate to form a sealed space in which the battery module is accommodated; a sensing member that is attached to the second side surface of the battery module and that has a terminal portion to be connected to an external terminal; and a gas discharge tube that extends from the sealed space to the outside of the battery case, wherein gases emitted from the battery cells and accumulated in the sealed space to increase an internal pressure of the sealed space are discharged to the outside of the battery case through the gas discharge tube by the internal pressure, wherein the first case covers a portion of an upper surface, a first side surface, and portions of left and right side surfaces, which are continuous from the first side surface, of the battery module, and a contact portion of the first case coupled with the second case extends in directions of portions of the upper surface, and portions of the left and right side surfaces, wherein the second case has a shape corresponding to the first case and covers a remaining portion of the upper surface, a second side surface, and remaining portions of the left and right side surfaces, which are continuous from the second side surface, of the battery module, and a contact portion of the second case coupled with the first case extends in directions of portions of the upper surface, and portions of the left and right side surfaces, wherein the second case is combined with the first case such that an inside side surface of the second case presses the sensing member in the direction toward the first case except for the terminal portion, and the contact portion of the first case and the contact portion of the second case come into surface contact with each other.

2. The battery module assembly according to claim 1, wherein each of the stacked unit battery modules has a first tab and a second tab for electrical connection, which protrude from a second side surface thereof and are distanced from each other.

3. The battery module assembly according to claim 2, wherein the sensing member has a hole through which the first tab and the second tab pass.

4. The battery module assembly according to claim 1, further comprising: a heat sink plate that is formed on an outside side surface of the first case and is in surface contact with the cell cover which protrudes from the unit battery module toward the heat sink plate; and a cooling fin attached to the heat sink plate, wherein the cell cover is formed of a heat conductive material and in surface contact with the battery cells.

5. The battery module assembly according to claim 1, comprising a partition that is disposed between the stacked battery cells, at a frame-shaped periphery portion of opposing surfaces of the battery cells, when two or more battery cells are combined with each other.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a perspective view illustrating a battery module assembly according to one embodiment;

(2) FIG. 2 is a cross-sectional view taken along line AA0 in FIG. 1;

(3) FIG. 3 is an exploded perspective view illustrating a unit battery module according to one embodiment;

(4) FIG. 4 is a combined perspective view illustrating battery module assemblies, which are connected to each other, according to one embodiment; and

(5) FIGS. 5 to 11 are diagrams showing a method of manufacturing a battery module assembly according to one embodiment.

MODE FOR INVENTION

(6) The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings. As for reference numerals associated with parts in the drawings, the same reference numerals will refer to the same or like parts through the drawings. It will be understood that, although the terms one surface, another surface, first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Hereinbelow, in the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments.

(7) Hereinbelow, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(8) FIG. 1 is a perspective view illustrating a battery module assembly according to one embodiment; FIG. 2 is a cross-sectional view taken along line AA0 in FIG. 1; FIG. 3 is an exploded perspective view illustrating a unit battery module according to one embodiment; and FIG. 4 is a combined perspective view illustrating battery module assemblies, which are connected to each other, according to one embodiment.

(9) A battery module assembly 1 according to one embodiment of the present invention includes: a base substrate 30; a battery module 10 including a plurality of unit battery modules 20, each of which includes at least one or more battery cells 21 and is covered by a cell cover 23; and a battery case 40 which is combined with the base substrate 30 and includes a first case 41 and a second case 42. The first case covers a rear surface portion of the battery module 10. The second case 42 covers a front surface portion of the battery module 10 and is combined with the first case 41.

(10) Each battery cell 21 included in the battery module 10 of the battery module assembly according to the present invention may be a secondary battery, such as a lithium secondary battery or a nickel-hydrogen secondary battery, which can be discharged and then recharged. However, the battery cell is not limited to those secondary batteries. Those skilled in the art will appreciate that any one selected from among various kinds of secondary batteries may be used as the battery cell as long as the selected secondary battery is rechargeable. For example, a nickel-hydrogen secondary battery is a secondary battery in which the anode is made of nickel, the cathode is made of a metal alloy for hydrogen storage, and the electrolyte is an alkali aqueous solution; and the nickel-hydrogen secondary battery is suitably used as an energy source for an Electric Vehicle (EV) or a Hybrid-Electric Vehicle (HEV). On the other hand, specifically a lithium secondary battery may be produced by using a metal oxide such as LiCoO.sub.2 as an anode active material and a carbon material as a cathode active material, by interposing a porous polymer separator between the cathode and anode, and by introducing a non-aqueous electrolyte liquid that contains lithium salt such as LiPF.sub.6 into a gap between the cathode and anode. Lithium ions are released from the anode active material and move into a carbon layer of the cathode during a charging process while the lithium ions are released from the carbon layer and move back into the anode active material during a discharging process. The non-aqueous electrolyte liquid functions as a media through which the lithium ions move between the anode and cathode. Since lithium secondary batteries have high energy density, a high operation voltage and good storage characteristics, they may be applied to or used for various electronic products as well as used as an energy source for an EV or HEV.

(11) A lithium secondary battery may be a box-shaped battery or a pouch-shaped battery which includes an electrode assembly and a pouch-shaped case that houses the electrode assembly. The pouch-shaped case may be formed by preparing a thin metal plate such as a thin aluminum plate and by performing insulation processing in which the surface of the thin metal plate is treated so as to be insulating. The insulation processing is performed by applying transformed polypropylene (polymer resin), for example, Casted Polypropylene as a thermally fused layer on the surface and forming a resin layer such as polyethylene terephthalate (PET) or nylon thereon. This structure is described as only an example of the lithium secondary battery. Accordingly, those skilled in the art will appreciate that the structure may vary according to the shape and kind of a battery.

(12) One or more battery cells 21 are stacked to form the unit battery module 20. In order for the battery module 10 in which the unit battery modules 20 are stacked to have a compact size, the battery module 10 is structured to have a small thickness, a wide width, and a long length. For example, an electrode assembly is accommodated in a case made of a laminate sheet that includes a resin layer and a metal layer, and a first tab 22a and a second tab 22b which serve as electrode terminals protrude from the surface of the case. Specifically, the electrode assembly may be accommodated in a pouch-shaped case made of an aluminum laminate sheet.

(13) The electrode assembly includes an anode, a cathode, and a separator. The separator is interposed between the anode and cathode which are stacked. The electrode assembly is called Jolly-roll winding type, stack type, or stack folding type according to a method of combining the anode, separator, and cathode. Details about these types are omitted because these types are well-known technologies.

(14) The unit battery module 20 is the smallest unit of the battery module. It includes one or more battery cells 21 connected to one another. In the unit battery module, at least two or more electrode terminals are connected in series with each other, and connection portions of the electrode terminals are bent and stacked. The battery cells 21 may be covered by a cell cover 23 made of a rigid material such as aluminum. Specifically, the cell cover 23 is preferably formed of a heat-transferable metallic member for the purpose of heat sinking of the battery module 10.

(15) As illustrated in FIG. 3, every two battery cells 21 are stacked with a partition 24 interposed therebetween when they are combined with each other, and the combined two stacked battery cells are accommodated in the cell cover 23, forming the unit battery module 20. In this case, the number of battery cells 21 included in one unit battery module 20 is not limited. The partition 24 disposed between the stacked battery cells 21 is optional. Therefore, those skilled in the art will appreciate that the partition 24 may be omitted, or an additional member may be included, in addition to the partition 24, in order to improve positional alignment of the battery cells 21 or reliability of combination. The battery cell 21 has the first tab 22a and the second tab 22b for electrical connection. The first tab 22a and the second tab 22b are distanced from each other and arranged on one side surface of each battery cell 21.

(16) The battery module 10 includes at least one or more unit battery modules 20 which are stacked on each other. The number of stacked unit battery modules 20 included in the battery module 10, or a method of stacking the unit battery modules 20 is not particularly limited. According to the present invention, the stacked structure of the battery module 10 shown in the drawings is just an example.

(17) The base substrate 30 supports the battery module 10 from the underside and may be a plate member made of a metal or any material. A coupling portion is formed on the outer circumferential surface of the base substrate 30 to combine the battery case 40 with the base substrate 30, and the form of the coupling portion varies depending on a coupling means. According to the present invention, the battery module 10 is seated on the base substrate 30 and then covered by the battery case 40, so that the battery module 10 is sealed inside the battery case 40. The battery case 40 is prepared by combining the first case 41 serving as a rear case with the second case 42 serving as a front case.

(18) The battery module 10 includes a plurality of unit battery modules 20 stacked on the base substrate 30, in which each unit battery module 20 includes at least one or more battery cells 21 and is covered by the cell cover 23. As illustrated in FIG. 3, each battery cell 21 included in the battery module 10 may have the first tab 22a and the second tab 22b which protrude from one side surface of the unit battery module 20 and enable electrical connection. The first tab 22a and the second tab 22b are distanced from each other and arranged on one side surface of the unit battery module 20. Those skilled in the art will appreciate that the construction and arrangement of the electrode terminals of the first tab 22a and the second tab 22b vary depending on the kind of the battery cell 21. Since the battery module 10, the unit battery modules 20, and the battery cells 21 have been described above in detail, a repetitive description thereabout will not be given hear.

(19) The battery case 40 accommodates the battery module 10 seated on the base substrate 30. The battery case 40 may be formed by combining the first case 41 serving as a rear case and the second case 42 serving as a front case so as to seal the accommodation space. As illustrated in FIG. 1, the second case 42 is disposed at the front part of the base substrate 30 in a manner of covering a portion of the upper surface, a first side surface (front surface), and portions of left and right side surfaces which are continuous from the first surface of the battery module 10 seated on the base substrate 30. The second case 42 may be formed at the front part of the base substrate 30 in a manner of covering a portion of the upper surface, the first surface (front surface), and portions of the left and right side surfaces which are continuous from the first surface of the battery module 10 so as to accommodate the battery module 10 therein by being combined with the first case 41. According to the present invention, the battery case 40 is prepared as separate two cases, the first case 41 and the second case 42, first. The first case 41 and the second case 42 are combined later to form the battery case 40. Because of this structure, the battery case 40 can press and be in pressure contact with an attached member such as a sensing member 50 attached to one side surface of the battery module 10 when the battery module assembly is manufactured, thereby more easily sealing the battery module 10. Furthermore, this structure has another advantage of enabling the battery module assembly to be more easily disassembled and reassembled when it is necessary to disassemble the battery module assembly 1 for a certain reason, for example, when abnormal operation of the battery module 10 accommodated inside the case 41 occurs. In addition, when a cooling device 70 described below is attached, the structure of the case has an advantage of effectively ensuring reliability of attachment of the cooling device 70, reliability of the contact between the battery module 10 and the cooling device, and reliability of functional operation of the battery module 10.

(20) The sensing member 50 generally includes a printed circuit board and is attached to a second side surface of the battery module 10 on which the first tab 22a and the second tab 22b of the unit battery module 20 are formed. The sensing member 50 is preferably attached to the second side surface of the battery module 10 in a manner of being in pressure contact with the inside surface of the second case 42 so that attachment force between the sensing member 50 and the battery module 10 is maintained and effective sealing inside the battery case 40 is ensured. Since the second case 42 is combined in such a manner that the inside surface thereof presses the sensing member 50, effective sealing of the accommodation space of the battery case 40 is achieved and maintained. The sensing member 50 has a terminal portion 50a to be connected to an external terminal and a sensing member cover 51 that can cover the terminal portion 50a.

(21) The cooling device 70 includes a heat sink plate 71 and cooling fins 72 that are attached to the heat sink plate 71 and may be cooled through air cooling. The cooling device 70 is attached to the first side surface of the battery module 10, which is opposite the second side surface to which the sensing member 50 is attached. The cooling device 70 is attached to the first case 41 to transfer heat generated from the battery module 10 accommodated in the first case 41, thereby cooling the battery module 10. As illustrated in FIG. 2, the heat sink plate 71 is attached in surface contact manner to the cell covers 23 of the unit battery modules 20 included in the battery module 10. Because of this surface contact, the heat generated from the battery module 10 is transferred to the cooling fins 72 attached to the heat sink plate 71. Accordingly, the cell covers 23 may be formed of a heat-conductive material. They may be formed of aluminum but not limited thereto. The cooling fins 72 have a protrusion form so that they can be connected to an additional cooler of a device to which the battery module assembly 1 is mounted. Here, the cooling fins 72 are preferably cooled through air cooling. However, those skilled in the art will appreciate that the cooling fins 72 exposed to the outside of the battery case 41 can be cooled by a certain cooling means using cooling water or other coolants.

(22) A gas discharge tube 60 may be added to discharge harmful gases, which may be emitted from the battery cells 21 of the battery module 10 accommodated in the battery case 40, outside the battery case 40. The gas discharge tube 60 may be formed by incorporating a connection tube, which can communicate with the inside and outside of the battery case 40, in one side surface of the battery case 40. As illustrated in FIG. 4, when two battery module assemblies 1 are combined with each other, the gas discharge tubes 60 are connected to each other so that harmful gases, generated in the battery cases 40, are discharged outside through the connected gas discharge tubes 60. Although FIG. 4 illustrates exemplary arrangement and shape of the gas discharge tubes 60, the arrangement and shape of the gas discharge tubes according to the present invention are not limited to the illustration. Various shapes of gas discharge tubes 60 may be used as long as the gas discharge tubes can be connected to each other to discharge gases outside the battery case 40.

(23) FIGS. 5 to 11 are diagrams illustrating a method of manufacturing a battery module assembly according to one embodiment.

(24) The method of manufacturing a battery module assembly 1 according to one embodiment includes: preparing a base substrate 30; combining a first case 41 with the base substrate 30 in a manner such that a rear surface portion of the base substrate 30 is covered; forming a battery module 10 in the first case 41 by stacking at least one or more unit battery modules 20; attaching a sensing member 50 to a first side surface of the battery module 10 which is not covered by the first case 41; and combining a second case 42 with a front surface portion of the base substrate 30 in such a manner that an inside surface of the second case 42 comes in pressure contact with the sensing member 50, an end of the second case 42 meets an end of the first case 41, and the battery module 10 can be accommodated in the first case and the second case.

(25) The method of manufacturing the battery module assembly 1 will be described in more detail with reference to FIGS. 5 to 11.

(26) First, as illustrated in FIG. 5, the base substrate 30 is prepared. The base substrate 30 described below is formed of a metallic material or other rigid materials so as to be able support the battery module 10, but the material of the base substrate 30 is not limited thereto.

(27) Next, as illustrated in FIG. 6, the first case 41 is combined with the base substrate 30 in a manner of covering the rear surface portion of the base substrate 30. At this point, a cooling device 70 may be attached to a first side surface of the first case 41 which is at a closed end of the first case 41. The cooling device 70 may include a heat sink plate 71 and cooling fins 72. Details about the cooling device 70 have been described above, so a repetitive description thereabout will not be given here. However, attachment of the cooling device 70 may be performed at a later stage instead of this stage unlike the example illustrated in FIG. 6. The attachment of the cooling device 70 may be performed by attaching the cooling device 70 to the first side surface of the first case 41 at any stage before manufacturing of the battery module assembly 1 is finished.

(28) Next, as illustrated in FIGS. 7 and 8, the unit battery modules 20 are inserted into the first case 40 through the opening of the first case 41 and stacked in the first case 41. That is, the battery module 10 is formed on the base substrate 30 through this step. The unit battery modules 20 and the battery cells 21 included in the battery module 10 have been described in detail, so a repetitive description thereabout will not be given here.

(29) Next, as illustrated in FIG. 9, a sensing member 50 is attached to a second side surface of the battery module on which a first tab 22a and a second tab 22b are formed. The sensing member 50 may be formed of a printed circuit board but the material of the sensing member 50 is not limited thereto. The sensing member 50 may have a terminal portion 50a to be connected to an external terminal, at a middle portion thereof.

(30) Next, as illustrated in FIG. 10, a second case 42 is combined to press the sensing member 50 toward the inside of the battery case. At this step, the inside surface of the second case 42 comes into pressure contact with the sensing member 50, and an open end of the second case 42 meets an open end of the first case 41. In this way, the second case 42 is combined with a front surface portion of the base substrate 30 so that the battery module 10 is accommodated in and sealed by the first and second cases 41 and 42.

(31) Next, as illustrated in FIG. 11, since the second case 42 is combined such that the terminal portion 50a of the sensing member 50 is not covered by the second case 42, an additional sensing member cover 51 may be installed to cover the terminal portion 50a. The method may further include a step of adding a gas discharge tube 60 through which harmful gases, generated from the battery module 10 accommodated in the battery case 40 that includes the first case 41 and the second case 42, are discharged outside (see FIG. 3). However, the shape and arrangement of the gas discharge tube 60 is not particularly limited according to position and space, but may suitably vary according to the structure and characteristic of devices to which the battery module assembly 1 is applied.

(32) Since the structure of each element including the battery case 40, the battery module 10, the cooling device 70, and the sensing member 50 has been described above in association with the battery module assembly 1 according to one embodiment, a repetitive description about these elements will not be given here.

(33) While the present invention has been described in conjunction with exemplary embodiments thereof, it is to be understood that the present description is not intended to limit the present invention to those exemplary embodiments but is described for only an illustrative purpose. Therefore, those skilled in the art will appreciate that various alternatives, modifications, and equivalents are possible without departing from the technical spirit of the present invention.

(34) It is to be understood that various alternatives, modifications, equivalents and other embodiments may be included within the spirit and scope of the present invention, and the specific protection scope will be defined only by the appended claims.

DESCRIPTION OF THE REFERENCE NUMERALS IN THE DRAWINGS

(35) 1: Battery module assembly 10: Battery module 20: Unit battery module 21: Battery cell 22: Battery tab 22a: First tab 22b: Second tab 23: Cell cover 24: Partition 30: Base substrate 40: Battery case 41: First case 42: Second case 50: Sensing member 50a: Terminal portion 51: Sensing member cover 60: Gas discharge tube 70: Cooling device 71: Heat sink plate 72: Cooling fin