UNIT BATTERY FOR MANUFACTURING BATTERY MODULE OR BATTERY PACK

Abstract

Disclosed is a unit battery for manufacture of battery modules or battery packs, the unit battery including an electrode assembly mounted in a cell case, the electrode assembly being capable of being reversibly charged and discharged, a positive electrode body portion, to which a positive electrode of the electrode assembly is connected, the positive electrode body portion being configured to serve as a positive electrode terminal for external connection while forming one surface of the cell case, a negative electrode body portion, to which a negative electrode of the electrode assembly is connected, the negative electrode body portion being configured to serve as a negative electrode terminal for external connection while forming the other surface of the cell case, and an insulation portion configured to electrically insulate the positive electrode body portion and the negative electrode body portion from each other.

Claims

1. A unit battery for manufacture of battery modules or battery packs, the unit battery comprising: an electrode assembly mounted in a cell case, the electrode assembly being capable of being reversibly charged and discharged; a positive electrode body portion, to which a positive electrode of the electrode assembly is connected, the positive electrode body portion being configured to serve as a positive electrode terminal for external connection while forming one surface of the cell case; a negative electrode body portion, to which a negative electrode of the electrode assembly is connected, the negative electrode body portion being configured to serve as a negative electrode terminal for external connection while forming the other surface of the cell case; and an insulation portion configured to electrically insulate the positive electrode body portion and the negative electrode body portion from each other.

2. The unit battery according to claim 1, wherein the cell case is formed in the shape of a hexahedron, and the one surface and the other surface are outer surfaces opposite each other based on a center of the hexahedron.

3. The unit battery according to claim 2, wherein the one surface and the other surface are two outer surfaces having relatively large areas, among six faces of the cell case.

4. The unit battery according to claim 1, wherein a total external area (Z) of the unit battery and a difference between a conductive external area (C) of the positive electrode body portion and a conductive external area (A) of the negative electrode body portion satisfy a relationship of 0≤|(C−A)/Z|<0.5.

5. The unit battery according to claim 1, wherein a conductive external area (C) of the positive electrode body portion, a conductive external area (A) of the negative electrode body portion, and a total external area (Z) of the unit battery satisfy a relationship of 0.1<(C+A)/Z<1.

6. The unit battery according to claim 1, wherein a total external area (Z) of the unit battery and a difference between a conductive external area (C) of the positive electrode body portion and a conductive external area (A) of the negative electrode body portion simultaneously satisfy a relationship of 0<|(C−A)/Z|<0.5 and a relationship of 0.1<(C+A)/Z<1.

7. The unit battery according to claim 1, wherein when the unit battery is viewed from the one surface, the positive electrode body portion is seen as having a size equivalent to 80% to 100% of a size of an outer surface of the unit battery, and when the unit battery is viewed from the other surface, the negative electrode body portion is seen as having a size equivalent to 80% to 100% of the size of the outer surface of the unit battery.

8. The unit battery according to claim 1, wherein each of the positive electrode body portion and the negative electrode body portion is made of a metal plate.

9. The unit battery according to claim 1, wherein at least one of the positive electrode body portion and the negative electrode body portion is configured to have a structure in which an insulative resin is added to an outer circumferential surface of a conductive plate.

10. The unit battery according to claim 1, wherein an insulative coating is applied to at least one of the positive electrode body portion and the negative electrode body portion such that a part of the conductive body portion is exposed to an outside.

11. The unit battery according to claim 1, wherein the positive electrode body portion forms the one surface of the cell case and at least some of outer surfaces adjacent to the one surface, and the negative electrode body portion forms the other surface of the cell case and at least some of outer surfaces adjacent to the other surface.

12. The unit battery according to claim 1, wherein the insulation portion is located between the positive electrode body portion and the negative electrode body portion along outer surfaces of the cell case adjacent to the one surface and the other surface.

13. The unit battery according to claim 1, wherein the unit battery is a high-capacity secondary battery having a capacity of 10 Ah or more or a high-current secondary battery having a current of 0.5 C or more.

14. A battery module comprising two or more unit batteries according to claim 1.

15. The battery module according to claim 14, wherein adjacent ones of the unit batteries are electrically connected to each other in a state in which the positive electrode body portion and the negative electrode body portion are in direct physical contact with each other.

16. The battery module according to claim 14, further comprising a cooling plate or a cooling pad disposed in physical contact with at least one of the positive electrode body portion and the negative electrode body portion of each of the unit batteries.

17. A battery pack comprising one or more battery modules according to claim 14.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0058] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0059] FIG. 1A is a plan view schematically showing a conventional exemplary pouch-shaped battery;

[0060] FIG. 1B is a plan view schematically showing another conventional exemplary pouch-shaped battery;

[0061] FIGS. 2A and 2B are perspective views schematically showing battery modules manufactured using the pouch-shaped unit batteries of FIGS. 1A and 1B, respectively;

[0062] FIG. 3 is a plan view schematically showing a structure in which a cooling unit is mounted in the battery module of FIG. 2A;

[0063] FIG. 4 is a perspective view schematically showing a conventional exemplary prismatic battery;

[0064] FIG. 5 is a perspective view schematically showing a battery module manufactured using the prismatic unit battery of FIG. 4;

[0065] FIG. 6A is a front view, a rear view, and a side view schematically showing a unit battery according to an embodiment of the present invention;

[0066] FIG. 6B is a sectional view taken along line X-X of FIG. 6A;

[0067] FIGS. 7A is a partial plan view schematically showing a battery module manufactured using the unit batteries of FIG. 6A;

[0068] FIGS. 7B to 7F are perspective views schematically showing examples in which battery modules are connected to each other in parallel or in series to constitute a battery pack;

[0069] FIG. 8A is a plan view schematically showing a structure in which a cooling unit is mounted in the battery module of FIG. 7A;

[0070] FIG. 8B is a schematic view showing the external shape of the battery module of FIG. 7B; and

[0071] FIG. 9 is a front view, a rear view, and a side view schematically showing a unit battery according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0072] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings; however, the category of the present invention is not limited thereto.

[0073] First, conventional batteries will be described with reference to the accompanying drawings.

[0074] FIGS. 1 to 5 are schematic views showing the structure of a conventional pouch-shaped battery (polymer battery), the structure of a conventional prismatic battery, a battery module manufactured by electrically connecting a plurality of pouch-shaped batteries to each other, and a battery module manufactured by electrically connecting a plurality of prismatic batteries to each other, respectively.

[0075] Referring to FIGS. 1A and 1B, a pouch-shaped battery 10 or 12 has a structure in which an electrode assembly (not shown) configured to be charged and discharged is received in a receiving portion 20 or 22 of a pouch-shaped case together with an electrolytic solution and in which a positive electrode terminal 30 or 32 and a negative electrode terminal 40 or 42 protrude from one end or opposite ends of the pouch-shaped case.

[0076] The pouch-shaped case is constituted by a metal layer and a resin layer added to each of opposite surfaces of the metal layer, and a sealed portion 50 or 52 thermally fused in order to hermetically seal the receiving portion 20 or 22 is formed at the pouch-shaped case so as to have a predetermined size.

[0077] In the pouch-shaped battery 10 or 12, energy storage capacity substantially depends on the size of the receiving portion 20 or 22. Consequently, the energy density of the battery 10 or 12 based on the total size thereof is reduced due to the positive electrode terminal 30 or 32, the negative electrode terminal 40 or 42, and the sealed portion 50 or 52, and the resistance of the battery 10 or 12 is increased due to small sizes of the positive electrode terminal 30 or 32 and the negative electrode terminal 40 or 42.

[0078] When a plurality of pouch-shaped unit batteries 10 or 12 is electrically connected to each other in order to constitute a battery module 70 or 72, as shown in FIGS. 2A and 2B, the positive electrode terminal 30 or 32 and the negative electrode terminal 40 or 42 must be connected to each other using a wire or a busbar 60 or 62. Consequently, it is necessary to secure a space for welding of the wire or the busbar 60 or 62, and the resistance of weld portions is also increased.

[0079] For these reasons, technology for stacking individual unit batteries 10 or 12 in a state of being mounted on a separate frame member (not shown) has been proposed; however, various problems naturally occur due to addition of the frame member.

[0080] Also, it is necessary to remove heat generated during charging and discharging of the battery module. As shown in FIG. 3, a cooling unit 80 must be brought into contact with one end of the battery module 70. The cooling unit 80 is constituted by a cooling insulation layer 80a abutting the unit batteries 10 and a cooling plate 80b abutting the cooling insulation layer 80a, and a refrigerant, such as a coolant 80c, flows in the cooling plate 80b.

[0081] In the battery module 70, heat is mainly generated from the positive electrode terminal 30 and the negative electrode terminal 40. Since the cooling unit 80 cannot be installed at the portions from which heat is mainly generated due to structural limits, however, cooling efficiency is greatly lowered.

[0082] Referring to FIGS. 4 and 5, a prismatic battery 14 and a battery module 64 manufactured using the prismatic battery 14 are schematically shown.

[0083] Referring to these figures, the prismatic battery 14 is configured to have a structure in which an electrode assembly (not shown) configured to be charged and discharged is received in a prismatic metal can 24 together with an electrolytic solution and in which a positive electrode terminal 34 and a negative electrode terminal 44 protrude from one end of the metal can 24.

[0084] In the same manner as the pouch-shaped battery described above, the energy density of the prismatic battery 14 is also reduced due to a dead space formed by the positive electrode terminal 34 and a negative electrode terminal 44, which protrude outwards, and the resistance of the prismatic battery 14 is increased due to small sizes of the terminals.

[0085] In addition, when a battery module 74 is manufactured using a plurality of prismatic batteries 14, it is necessary to provide a space for welding of a connection member 64, such as a wire or a busbar, and the resistance of weld portions is also increased.

[0086] FIG. 6A is a front view, a rear view, and a side view schematically showing a unit battery according to an embodiment of the present invention, and FIG. 6B is a schematic sectional view taken along line X-X of FIG. 6A.

[0087] Referring to FIGS. 6A and 6B, the unit battery 100 includes an electrode assembly 300 mounted in a cell case 200, the electrode assembly 300 being capable of being reversibly charged and discharged, a positive electrode body portion 400, to which a positive electrode 340 of the electrode assembly 300 is connected, the positive electrode body portion 400 being configured to serve as a positive electrode terminal for external connection while forming one surface 240 of the cell case 200, a negative electrode body portion 500, to which a negative electrode 350 of the electrode assembly 300 is connected, the negative electrode body portion 500 being configured to serve as a negative electrode terminal for external connection while forming the other surface 250 of the cell case 200, and an insulation portion 600 configured to electrically insulate the positive electrode body portion 400 and the negative electrode body portion 500 from each other.

[0088] As a result, the cell case 200 is apparently constituted by the positive electrode body portion 400, the negative electrode body portion 500, and the insulation portion 600. Consequently, the positive electrode body portion 400 forms one surface 240 of the cell case 200, and the negative electrode body portion 500 forms the other surface 250 of the cell case 200.

[0089] The cell case 200 is formed in the shape of a rectangular parallelepiped, and one surface 240 of the positive electrode body portion 400 and the other surface 250 of the negative electrode body portion 500 are symmetric with respect to the center of the rectangular parallelepiped while having the largest area.

[0090] When the unit battery 100 is viewed from one surface 240 of the positive electrode body portion 400, therefore, only the positive electrode body portion 400 is substantially seen, and the negative electrode body portion 500 is not visible. When the unit battery 100 is viewed from other surface 250 of the negative electrode body portion 500, on the other hand, only the negative electrode body portion 500 is substantially seen, and the positive electrode body portion 400 is not visible.

[0091] In addition, when the unit battery 100 is viewed from the side, the positive electrode body portion 400 extends to form a part 244 of an outer surface adjacent to one surface 240 of the cell case 200, and the negative electrode body portion 500 extends to form a part 255 of the outer surface adjacent to the other surface 250 of the cell case 200. As a result, each of the positive electrode body portion 400 and the negative electrode body portion 500 is formed so as to be larger than a corresponding one of the surfaces of the cell case 200, which is a rectangular parallelepiped.

[0092] The insulation portion 600 is disposed at the interface between the positive electrode body portion 400 and the negative electrode body portion 500, and the insulation portion 600 is configured to have a structure in which an insulative resin is added to an outer circumferential surface of a conductive plate constituting each of the positive electrode body portion 400 and the negative electrode body portion 500.

[0093] Since the positive electrode terminal and the negative electrode terminal do not protrude outwards from a main body of the unit battery 100, as described above, no dead space is formed, whereby it is possible to maximize energy density. In addition, since one surface 240 and the other surface 250, which are large outer surfaces, of the cell case 200, which is a rectangular parallelepiped, substantially serve as the positive electrode terminal and the negative electrode terminal, respectively, increase in resistance is not caused, and cooling efficiency is high.

[0094] As shown in FIGS. 7A to 7F, unit batteries 100 may be electrically connected to each other only through physical contact therebetween without using a separate connection member, such as a wire or a busbar, and therefore it is possible to very easily manufacture a battery module 700. In addition, electrical connection between the unit batteries may be achieved through large-area contact without using a separate connection member, such as a wire or a busbar, and therefore it is possible to reduce contact resistance.

[0095] Referring to FIG. 7B, two or more (n being a natural number equal to or greater than 2) unit batteries may be connected to each other in series to constitute a battery module 700 having desired voltage. For example, when 96 (n=96) unit batteries 100 having an average voltage of 3.8 V are connected to each other in series, it is possible to manufacture a battery module 700 having a voltage of 300 to 400 V, which is necessary to manufacture a battery pack required for a general electric vehicle (EV).

[0096] When a plurality (n being a natural number equal to or greater than 2) of battery modules 700 is connected to each other in parallel, as shown in FIG. 7C or 7D, it is possible to increase the capacity thereof. On the other hand, when a plurality (n being a natural number equal to or greater than 2) of battery modules 700 is connected to each other in series, as shown in FIG. 7E or 7F, it is possible to increase the voltage thereof.

[0097] For example, when seven or eight battery modules 700 are connected to each other in series, the battery modules may be used in a home solar system or a low voltage power boosting stop and go vehicle system, and it is also possible to manufacture an insulated gate bipolar transistor (IGBT) for energy storage systems (ESS) having a voltage of 900 to 1000 V. Electrical connection between the battery modules 700 may be achieved by connection or welding between end plates mounted to opposite ends of the battery module assembly. In addition, when a cooling unit 800 is added to one side of the battery module 700, as shown in FIG. 8A, the cooling unit can be brought into direction contact with the positive electrode body portion 400 and the negative electrode body portion 50, which are electrode terminals, of each unit battery 100, whereby it is possible to achieve excellent cooling efficiency.

[0098] Specifically, since the battery module has an approximately rectangular parallelepiped structure, as shown in FIG. 7A, the rectangular parallelepiped battery module 700a has six faces A, B, C, D, E, and F, as can be seen from FIG. 8B. This shape may be identically applied to a battery pack.

[0099] As shown in FIG. 8A, the cooling plate may be added to at least one of the faces A, B, C, and D of the battery module 700a, which have relatively large areas. Although it is possible to cool the faces E and F, configuration with avoidance of electrical connection may not be easy, and cooling efficiency thereof may be lower than in the faces A, B, C, and D.

[0100] An end plate having a connection member (e.g. a metal plate) connected to or brought into contact with a corresponding one of the terminals of the unit battery is located at each of the faces E and F, and a member for insulation from the outside, e.g. a paint material including ceramic or a polymer film, is installed at each of the faces A, B, C, D, E, and F.

[0101] FIG. 9 is a front view, a rear view, and a side view schematically showing a unit battery 100a according to another embodiment of the present invention.

[0102] Referring to FIG. 9, the unit battery 100a is different from the unit battery 100 of FIG. 6A in that an insulative coating 280a is applied along an outer circumferential surface of each of a positive electrode body portion 400a and a negative electrode body portion 500a such that a central region of each of the positive electrode body portion and the negative electrode body portion is exposed to the outside.

[0103] The insulative coating 280a of the unit battery 100a reduces danger of electric shock during handling of the unit battery 100a for manufacture of battery modules or battery packs, whereby work convenience is improved.

[0104] Those skilled in the art to which the present invention pertains will appreciate that various applications and modifications are possible within the category of the present invention based on the above description.