METHOD FOR WELDING ELECTRODE LEADS OF SECONDARY BATTERY MODULE AND COMPACT SECONDARY BATTERY MODULE USING THE SAME

Abstract

Disclosed is a compact secondary battery module, which includes a cartridge assembly having a plurality of cartridges stacked while accommodating cells, respectively, so that a plurality of lead overlapping portions where leads of adjacent cells overlap with each other are located at a cartridge sidewall with a predetermined pattern; and a sensing housing having a plurality of bus bars located and welded corresponding to the lead overlapping portions, respectively, the sensing housing being capable of being arranged at a side of the cartridge assembly, wherein a first lead of a cell of each lead overlapping portion is configured to have a shorter width than a second lead having a polarity opposite to the first lead as much as a predetermined width, and in a state where the sensing housing is coupled to the cartridge assembly, a corresponding bus bar comes into contact with the second lead substantially on the same line as the first lead, and the second lead and the bus bar are welded to each other.

Claims

1. A compact secondary battery module, comprising: a cartridge assembly having a plurality of cartridges stacked while accommodating cells, respectively, so that a plurality of lead overlapping portions where leads of adjacent cells overlap with each other are located at a cartridge sidewall with a predetermined pattern; and a sensing housing having a plurality of bus bars located and welded corresponding to the lead overlapping portions, respectively, the sensing housing being capable of being arranged at a side of the cartridge assembly, wherein a first lead of a cell of each lead overlapping portion is configured to have a shorter width than a second lead having a polarity opposite to the first lead as much as a predetermined width, and in a state where the sensing housing is coupled to the cartridge assembly, a corresponding bus bar comes into contact with the second lead substantially on the same line as the first lead, and the second lead and the bus bar are welded to each other.

2. The compact secondary battery module according to claim 1, further comprising: a barrier provided at a side of each cartridge to protect the cell during a welding work.

3. The compact secondary battery module according to claim 1, wherein the lead of each cell is bent at a right angle at about 1 mm from a lead insulation portion in a state of being accommodated in the corresponding cartridge.

4. The compact secondary battery module according to claim 1, wherein the welding is laser welding.

5. The compact secondary battery module according to claim 4, wherein in the laser welding, laser is irradiated substantially perpendicular to the sensing housing.

6. The compact secondary battery module according to claim 1, wherein the bus bar and the second lead are made of copper, and the first lead is made of aluminum.

7. The compact secondary battery module according to claim 1, wherein the sensing housing further includes a battery management system (BMS) circuit board configured to manage voltage and/or temperature data of each cell detected by each bus bar.

8. The compact secondary battery module according to claim 7, wherein the sensing housing is coupled to the cartridge assembly by means of snap-fitting or hooking.

9. The compact secondary battery module according to claim 7, further comprising: a sensing cover coupled to the sensing housing.

10. The compact secondary battery module according to claim 9, wherein the sensing cover is coupled to the sensing housing by means of snap-fitting or hooking.

11. The compact secondary battery module according to claim 1, wherein two neighboring cartridges of the cartridge assembly are coupled to each other by means of hooking.

12. The compact secondary battery module according to claim 1, wherein the cartridge assembly further includes an upper cover and a lower cover coupled to cartridges at both ends thereof by means of hooking.

13. A method for welding electrode leads of a compact secondary battery module, comprising: (a) preparing a plurality of cells having leads which have opposite polarities and are bent in opposite directions so that a first lead is formed to have a shorter width than a second lead as much as a predetermined width; (b) forming a cartridge assembly by stacking a plurality of cartridges accommodating cells, respectively, so that lead overlapping portions where leads of adjacent cells with opposite polarities overlap with each other are formed at a cartridge sidewall with a predetermined pattern; (c) disposing a sensing housing having a plurality of bus bars respectively installed corresponding to the lead overlapping portions at a side of the cartridge assembly so that a corresponding bus bar comes into contact with the second lead substantially on the same line as the first lead; and (d) welding the second lead and the bus bar of each lead overlapping portion.

14. The method for welding electrode leads of a compact secondary battery module according to claim 13, wherein in the step (b), a cartridge having a barrier at each sidewall where the first lead and the second lead are disposed is used.

15. The method for welding electrode leads of a compact secondary battery module according to claim 13, wherein in the step (a), each lead is bent at a right angle at about 1 mm from a lead insulation portion of the cell in a state of being accommodated in the corresponding cartridge.

16. The method for welding electrode leads of a compact secondary battery module according to claim 13, wherein the step (d) uses a laser welder.

17. The method for welding electrode leads of a compact secondary battery module according to claim 16, wherein a laser irradiation direction of the laser welder is substantially perpendicular to the sensing housing.

18. The method for welding electrode leads of a compact secondary battery module according to claim 13, wherein the bus bar and the second lead are made of copper, and the first lead is made of aluminum.

19. A compact secondary battery module, manufactured by the method of claim 13.

20. A secondary battery pack, comprising the compact secondary battery module defined in claim 19.

Description

DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the foregoing disclosure, serve to provide further understanding of the technical features of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawing.

[0037] FIG. 1 is a perspective view showing a secondary battery module according to an embodiment of the present disclosure.

[0038] FIG. 2 is an exploded perspective view showing the secondary battery module according to an embodiment of the present disclosure.

[0039] FIG. 3 is a partial perspective view showing a sensing housing available for the secondary battery module according to an embodiment of the present disclosure.

[0040] FIG. 4 is a partial perspective view showing a cartridge assembly available for the secondary battery module according to an embodiment of the present disclosure.

[0041] FIG. 5 is an enlarged view showing a portion A of FIG. 4.

[0042] FIG. 6 is a cross-sectioned view showing a curved portion of a lead of a cell of the secondary battery module according to an embodiment of the present disclosure.

[0043] FIG. 7 is a schematic diagram for illustrating a welding process between a bus bar of the sensing housing and each cell lead, when the secondary battery module according to an embodiment of the present disclosure is assembled.

[0044] FIG. 8 is an exploded perspective view showing a secondary battery module according to an embodiment of the present disclosure.

[0045] FIG. 9 is a perspective view of FIG. 8 in an assembled state.

BEST MODE

[0046] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation.

[0047] Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the disclosure, so it should be understood that other equivalents and modifications could be made thereto without departing from the scope of the disclosure.

[0048] FIG. 1 is a perspective view showing a secondary battery module according to an embodiment of the present disclosure, and FIG. 2 is an exploded perspective view showing the secondary battery module according to an embodiment of the present disclosure.

[0049] Referring to FIGS. 1 and 2, a compact secondary battery module 100 according to an embodiment of the present disclosure includes a cartridge assembly 20 in which a plurality of cartridges 10 accommodating cells 2, respectively, are stacked, and a sensing housing 30 coupled to a side of the cartridge assembly 20 by means of, for example, one-touch, snap-fitting, hooking or the like.

[0050] The cartridge assembly 20 is prepared by stacking a plurality of cartridges 10 which are made by injection-molding plastic and respectively have an accommodation portion capable of accommodating the cell 2. The cartridges 10 may be coupled to each other by means of snap-fitting or hooking. As shown in FIG. 6, in the cartridge assembly 20, a plurality of lead overlapping portions 16 where leads 12, 14 having opposite polarities of neighboring cells 2, for example a first lead 12 made of aluminum and having a first polarity and a second lead 14 made of copper and having a second polarity opposite to the first polarity, overlap with each other are located at the sidewall of each cartridge 10 with a predetermined pattern.

[0051] In addition, the cartridge assembly 20 has an upper cover 11 and a lower cover 13, coupled to the cartridges 10 at both ends by means of, for example, hooking. The upper cover 11 and the lower cover 13 are injection-molded to have substantially the same shape as the individual cartridge 10 of the cartridge assembly 20, respectively. It will be understood by those skilled in the art that the upper cover 11 and the lower cover 13 have a function of protecting the cell 2 accommodated in the cartridges 10 at both ends and have a function and structure to finish and surround the appearance of the secondary battery module 100.

[0052] FIG. 3 is a partial perspective view showing a sensing housing available for the secondary battery module according to an embodiment of the present disclosure, FIG. 4 is a partial perspective view showing a cartridge assembly available for the secondary battery module according to an embodiment of the present disclosure, and FIG. 5 is an enlarged view showing a portion A of FIG. 4.

[0053] Referring to FIGS. 1 to 5, the sensing housing 30 is provided with a plurality of bus bars 32 corresponding to the lead overlapping portions 16, respectively. Each bus bar 32 may be made of, for example, copper. In addition, the sensing housing 30 may be injection-molded in an approximately rectangular shape by, for example, insulating plastic, and a plurality of accommodation holes 35 capable of respectively accommodating the bus bars 32 are formed therethrough in a predetermined pattern. At an approximate center of the sensing housing 30, a BMS circuit board 34 functioning to collect voltage and/or temperature data of each cell 2 sensed by the corresponding bus bar 32, balancing the corresponding cell 2 by means of the collected data, and transferring the data to another controller (not shown) of the module is installed. The BMS circuit board 34 is electrically connected to one end of each bus bar 32.

[0054] The first lead 12 and the second lead 14 extend and bend from a side of each cell 2 by a predetermined length and have a predetermined width, respectively. The first lead 12 of each cell 2 is bent by 90 degrees upwards on the drawing, and the second lead 14 is bent 90 degrees downwards on the drawing. As shown in FIG. 5, a width W1 of the first lead 12 is shorter than a width W2 of the second lead 14, and thus the sum of the width W1 of the first lead 12 and a length Lb of the bus bar 32, explained later, may be substantially identical to the width W2 of the second lead 14.

[0055] In FIG. 3, the reference sign 36 represents a pair of data communication ports for exchanging data between BMS circuit board 34, when a plurality of secondary battery modules 100 are coupled, and the reference sign 38 represents a temperature data port for receiving a signal of a temperature sensor (not shown) for measuring an internal temperature of the secondary battery module 100. The reference sign 31 respectively represents a positive electrode terminal and a negative electrode terminal of the secondary battery module 100.

[0056] As described above, the first lead 12 of the cell 2 of each lead overlapping portion 16 is configured to have a shorter width than the second lead 14 having a polarity opposite to the first lead 12 as much as a predetermined width, and when the sensing housing 30 is coupled to the cartridge assembly 20, the second lead 14 and the bus bar 32 may be welded by means of, for example, laser welding in a state where each corresponding bus bar 32 come into contact with the second lead 14 substantially on the same line as the first lead 12. According to a modified embodiment, it would be understood by those skilled in the art that the first lead 12, the second lead 14, and the bus bars 32 corresponding thereto may also be coupled together by ultrasonic welding.

[0057] FIG. 6 is a cross-sectioned view showing a curved portion of a secondary battery module according to an embodiment of the present disclosure, and FIG. 7 is a schematic diagram for illustrating a welding process between a bus bar of the sensing housing and each cell lead, when the secondary battery module according to an embodiment of the present disclosure is assembled.

[0058] Referring to FIGS. 6 and 7, the sensing housing 30 is coupled to a side of the cartridge assembly 20 in a state where the first lead 12 and the second lead 14 of the cells 2 adjacent to the respective lead overlapping portions 16 overlap with each other in contact, thereby configuring the secondary battery module 100. In this case, the bus bar 32, the first lead 12 and the second lead 14 are positioned in order in a direction from the outside of the module 100, namely from a side where laser welding is performed, toward the cartridge assembly. In this arrangement, when welding is performed between the leads 12, 14 and between the bus bar 32 and the leads 12, 14 in this deployed state, particularly when laser is irradiated in a direction substantially perpendicular to the sensing housing 30, each cartridge 10 has a barrier 18 on a side thereof in order to protect the cells 2 accommodated in each cartridge 10. It will be fully understood by those skilled in the art that the barrier 18 serves as a blocking wall to prevent a laser (not shown) emitting from a laser device (not shown) from being directly irradiated onto the cell 2.

[0059] According to an embodiment of the present disclosure, in order to configure the secondary battery module in a compact design to enhance energy efficiency to the maximum, the leads 12, 14 of each cell 2 may be bent at a right angle at a point of about 0.8 to 1.2 mm from a lead insulating unit 15 in state of being accommodated in the corresponding cartridge.

[0060] Referring to FIG. 8 which is an exploded perspective view showing the secondary battery module according to an embodiment of the present disclosure a the present disclosure, which is net yet completely assembled, and FIG. 9 which is a perspective view in a completely assembled state, in a state where the sensing housing 30 is coupled to the cartridge assembly 20, a sensing cover 40 is coupled to the sensing housing 30 to protect the BMS circuit board 34 and bus bar 32. The sensing cover 40 may be coupled to the sensing housing 30 by means of snap-fitting or hooking.

[0061] A method for welding electrode leads of a secondary battery module according to another embodiment of the present disclosure will be described.

[0062] First, a plurality of cells 2 in which a width W1 of the first lead 12 is shorter than a width W2 of the second lead 14 (for example, as much as a length Lb of each bus bar 32, and leads 12, 14 with opposite polarities are bent in opposite directions. Here, it could be fully understood that the width W1 of the first lead 12 may be shorter than the width W2 of the second lead 14 when the leads are initially manufactured, or the first lead 12 and the second lead 14 may be manufactured to have the same width and then the first lead 12 of each cell 2 may be cut by a predetermined length so that the first lead 12 have the width W1. In addition, in a state where the cell 2 is accommodated in the corresponding cartridge 10, the leads 12, 14 of the cell may be bent at a point of approximately 0.8 to 1.2 mm, preferably 1 mm, from the lead insulation portion 15 at a right angle, thereby maximizing the energy efficiency.

[0063] Subsequently, a plurality of cartridges 10 respectively accommodating the cells 2 are stacked to form the cartridge assembly 20 so that the leads 12, 14 of the neighboring cells 2 with opposite polarities overlap with each other and thus the lead overlapping portions 16 are positioned in a predetermined pattern on the sidewall of the cartridges 10. Each cartridge 10 of the cartridge assembly 20 may include an accommodation portion capable of accommodating the cell 2, and may also have a hook or a slot so that a pair of adjacent cartridges 10 may be coupled to each other by means of snap-fitting or hooking, as being easily understood by those skilled in the art. In addition, at both sides of the cartridge assembly 20, the upper cover 11 and the lower cover 13 which may accommodate and protect the cell 2 are coupled to each other by means of, for example, snap-fitting or hooking. In addition, the cartridge 10 at which the first lead 12 and the second lead 14 are placed may employ a cartridge having a barrier 18 at a side thereof so that the cell 2 may be protected against the laser during the laser welding operation described below.

[0064] Next, the sensing housing 30 having a plurality of bus bars 32 respectively installed corresponding to respective lead overlapping portions 16 is coupled to a side of the cartridge assembly 20 by means of snap-fitting or hooking so that the corresponding bus bar 32 may come into contact with the second lead 14 substantially on the same line as the first lead 12. In this case, as described above, the bus bars 32 are arranged in the sensor housing 30 in advance with a predetermined pattern. Here, the first lead 12 is made of aluminum, and the second lead 14 and the bus bar 32 are made of copper.

[0065] Finally, the second lead 14 and the bus bar 32 of each lead overlapping portion 16 are welded. In this stage, a welding system having a plurality of welding points may be used, and also an individual laser welder may be used to perform point welding several times. In addition, it would be fully understood by those skilled in the art that a separate laser welder or welding point may be used between the first lead 12 and the second lead 14. Moreover, the laser welder may irradiate laser in a direction substantially perpendicular to the sensing housing 30.

[0066] The secondary battery modules 100 according to the above embodiments may electrically connected to each other in series or in parallel and are accommodated in a predetermined case to provide a compact secondary battery pack for a power storage device for a home photovoltaic (PV) solar energy panel.

[0067] The foregoing description is merely illustrative of the technical features of the present disclosure, and various modifications and variations can be made by those having ordinary skill in the art without departing from the essential characteristics of the present disclosure. Therefore, the embodiments disclosed herein are not intended to limit but to illustrate the technical features of the present disclosure, and the scope of the technical features of the present disclosure is not limited by these embodiments. The scope of the present disclosure should be construed according to the appended claims, and all technical features falling within its equivalent scope should be construed as being included in the scope of the present disclosure.

INDUSTRIAL APPLICABILITY

[0068] The present disclosure relates to a method for welding electrode leads of a secondary battery module and a compact secondary battery module using the same, and is particularly applicable to industries related to welding of electrode leads of a secondary battery module.