Battery module

Abstract

To provide a battery module in which a voltage difference between a plurality of battery cells sharing a tab member is minimized.SOLUTION: A battery module is provided. This battery module includes a plurality of battery cells disposed in a first column and a second column, which are parallel to each other, a holder that accommodates the battery cells, and tab members that are disposed in accordance with the first column and the second column and welded to electrode terminals of the battery cells. The tab member includes a main body part disposed between the first column and the second column, a first neck part connected to the main body part, disposed in the first column, and connected to the electrode terminal in the first column and the like with a first tab, and a second neck part connected to the main body part, disposed in the second column, and connected to the electrode terminal in the second column and the like with a second tab.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery module, and more particularly to a battery module that minimizes voltage differences between cells. [Background technology]

[0002] A rechargeable battery is a battery that, unlike a primary battery, can be repeatedly charged and discharged. Small-capacity secondary batteries are used in small, portable electronic devices such as mobile phones, laptops, and camcorders. Large-capacity and high-density secondary batteries are used as power sources for driving motors in hybrid and electric vehicles, and for energy storage.

[0003] The secondary battery can be used as a secondary battery module including a plurality of battery cells connected in series and / or parallel to drive a motor of a hybrid vehicle, which requires a relatively high energy density. For example, in order to realize a secondary battery module with a relatively high output (e.g., an electric vehicle), a secondary battery module is formed by connecting together electrode terminals of a plurality of battery cells, the number of which corresponds to the desired amount of power.

[0004] For example, a secondary battery module is formed by housing a plurality of battery cells in a holder and connecting them in series and / or parallel with tabs. The secondary battery module includes tabs for connecting the battery cells because of the high voltage and current required by consumers' usage conditions, and a battery management system connected to the tabs.

[0005] In this case, since multiple battery cells are connected to one tab, a voltage difference may occur between the battery cells due to discharge, which may reduce the lifespan of the battery cells. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE PRESENT EMBODIMENT One embodiment of the present invention provides a secondary battery module that minimizes a voltage difference between a plurality of battery cells that share a tab member. [Means for solving the problem]

[0007] A secondary battery module according to one embodiment of the present invention includes a plurality of battery cells arranged in a first row and a second row parallel to each other, a holder for accommodating the battery cells, and tab members arranged corresponding to the first row and the second row and welded to electrode terminals of the battery cells, the tab member including a main body portion arranged between the first row and the second row, a first neck portion connected to the main body portion, arranged in the first row and connected to the electrode terminals of the first row with a first tab, and a second neck portion connected to the main body portion, arranged in the second row and connected to the electrode terminals of the second row with a second tab.

[0008] The first neck portion includes a pair of the first tabs for electrical connection, and the pair of the first tabs can be welded to and electrically connected to electrode terminals of each of the two battery cells arranged in the first row direction. The first neck portion is disposed between the two battery cells in the first row direction, avoiding the two battery cells arranged in the first row direction, and the pair of first tabs are connected to the first neck portion, avoiding the two battery cells arranged in the first row direction, and can be connected to the electrode terminals of each of the two battery cells.

[0009] The second neck portion has a pair of second tabs that are electrically connected, and the pair of second tabs can be welded to and electrically connected to electrode terminals of each of two battery cells arranged in the second row direction.

[0010] The second neck portion is disposed between the two battery cells in the second row direction, avoiding two battery cells arranged in the second row direction, and a pair of second tabs are connected to the second neck portion, avoiding the two battery cells arranged in the second row direction, and can be connected to the electrode terminals of each of the two battery cells.

[0011] The battery cells are cylindrical secondary batteries, and the axial centers of the battery cells arranged in the first row and the axial centers of the battery cells arranged in the second row are offset from each other in a direction intersecting the first row and the second row, and side surfaces of two battery cells arranged at ends of the first row and the second row may have the offset angle in the arrangement direction of the first row and the second row.

[0012] The tab member may include a main body portion disposed between the first row and the second row, and a bent portion extending in the offset angular direction on side surfaces of the two battery cells, connected to an end of the main body portion, and formed with a convex cross section downward from the side surfaces.

[0013] The bent portion may have a radius of curvature, and an upper end bending start point of the radius of curvature may be positioned above a diagonal line of rounded portions formed at both axial ends of the battery cell.

[0014] The bent portion may have a radius of curvature, and an upper end bending start point of the radius of curvature may be located above rounded portions formed at both axial ends of the battery cell.

[0015] The bent portion may further include a lateral convex surface that is convex toward a side surface of the battery cell.

[0016] The bent portion may be formed into a curved cross section (U) that is convex downward from the side surface.

[0017] The bent portion may be formed into an angular cross section (V) that is convex downward from the side surface.

[0018] The connection structure of the first tab may include an eleventh connection that is welded to the electrode terminal into two branches and bent, extending in a height direction, followed by a twelfth connection that extends in a direction perpendicular to the first row, and then a thirteenth connection that extends in the first row direction to connect to the first neck portion.

[0019] The connection structure of the second tab may include a 21st connection that is welded to the electrode terminal into two branches and bent, extending in a height direction, followed by a 22nd connection that extends in a direction perpendicular to the second row, and then a 23rd connection that extends in the second row direction to connect to the second neck portion. Effect of the Invention

[0020] In the secondary battery module according to the embodiment, the tab member is connected to the electrode terminals of the battery cells in the first row and the battery cells in the second row, including the body portion, the first neck portion, the second neck portion, and the first and second tabs, so that the body portion of the tab member can be shared. Therefore, the voltage difference between the battery cells can be minimized, and the lifespan of the battery cells can be prevented from being shortened. [Brief description of the drawings]

[0021] [Figure 1] 1 is an exploded perspective view of a secondary battery module according to a first embodiment of the present invention; [Diagram 2] 1 is a plan view of a secondary battery module according to a first embodiment of the present invention; [Diagram 3] 3 is a plan view of a tab member that connects the four battery cells in FIG. 2. [Figure 4] FIG. 3 is a perspective view of the tab member of FIG. 2. [Diagram 5] 4 is a cross-sectional view taken along line VV in FIG. 3. [Figure 6] 13 is a plan view of a tab member that connects four battery cells in a secondary battery module according to a second embodiment of the present invention. FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 11 is a cross-sectional view of a secondary battery module according to a third embodiment of the present invention. [Figure 9] 11 is a cross-sectional view of a secondary battery module according to a fourth embodiment of the present invention. [Figure 10] 13 is a cross-sectional view of a secondary battery module according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the embodiments. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not necessary for the explanation are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0023] Fig. 1 is an exploded perspective view of a secondary battery module according to a first embodiment of the present invention, and Fig. 2 is a plan view of the secondary battery module according to the first embodiment of the present invention. Referring to Fig. 1 and Fig. 2, a secondary battery module 1 of the first embodiment includes a plurality of battery cells 10, a holder 20 that houses the battery cells 10, and tab members 50 that are welded to electrode terminals 40 of the battery cells 10, etc.

[0024] The multiple battery cells 10 are cylindrical secondary batteries, and are provided with electrode terminals 40 at both ends of the cylindrical secondary battery in the axial direction. That is, the electrode terminals 40 include a positive terminal 41 and a negative terminal 42 provided at both ends of each battery cell 10 in the axial direction.

[0025] The holder 20 includes a bottom holder 21 and a tab holder 22. The bottom holder 21 and the tab holder 22 form a honeycomb structure therein to accommodate a plurality of battery cells 10 spaced apart in a first direction (x-axis direction) and a second direction (y-axis direction) intersecting the first direction, and are coupled to each other in a third direction (z-axis direction) intersecting the second direction and firmly fastened by fastening members 23.

[0026] 1, the bottom holder 21 accommodates the lower side of the battery cell 10, and the tab holder 22 accommodates the upper side of the battery cell 10. In this state, the bottom holder 21 and the tab holder 22 are fastened together by fastening members 23.

[0027] In addition, the bottom holder 21 and the tab holder 22 may be further connected to each other by a snap fit structure of a connecting portion 24 provided on the outside of the bottom holder 21 and a protrusion 25 provided on the outside of the tab holder 22 corresponding to the connecting portion 24.

[0028] Figure 3 is a plan view of a tab member connecting the four battery cells of Figure 2. Referring to Figures 1, 2 and 3, a plurality of battery cells 10 are housed in a holder 20 and arranged in a first row (R1) and a second row (R2) that are parallel to each other. The first row (R1) and the second row (R2) are set in a second direction and are spaced apart from each other in the first direction.

[0029] As an example, in the first row (R1), the positive electrode terminal 41 is disposed at the top, and the negative electrode terminal 42 is disposed at the bottom. In the second row (R2), the positive electrode terminal 41 is disposed at the bottom, and the negative electrode terminal 42 is disposed at the top.

[0030] The axial centers of the battery cells 10 arranged in the first row (R1) and the axial centers of the battery cells 10 arranged in the second row (R2) are shifted from each other in a direction intersecting the first row (R1) and the second row (R2). This makes it possible to prevent the cylindrical battery cells 10 from being arranged adjacent to each other.

[0031] That is, the battery cells 10 arranged in the second row (R2) maintain a state shifted in the second direction (y-axis direction) relative to the battery cells 10 arranged in the first row (R1). Therefore, the side faces of the two battery cells 10 arranged at the ends of the first row (R1) and the second row (R2) have an angle (θ) that is offset from the arrangement direction of the first row (R1) and the second row (R2).

[0032] As an example, the tab member 50 may be formed to include a nickel material, electrically connects the battery cells 10 in parallel and / or series, and is connected to the battery management system (BMS) 30. The tab member 50 may be formed by stamping a thin plate material.

[0033] As an example, the battery management system (BMS) 30 may be installed on the side of the bottom holder 21 and the tab holder 22. The tab members 50 each have an output end 54 on one side in the first direction (x-axis direction), and are electrically connected to the battery management system (BMS) 30 at the output end 54.

[0034] The tab member 50 is disposed in the mounting grooves 221 of the bottom holder 21 and the tab holder 22 to connect the corresponding electrode terminals 40, etc. A protrusion 222 is provided on one side of the mounting groove 221 and is coupled to a coupling hole (H) corresponding to the tab member 50.

[0035] Therefore, the mounting groove 221 can set the position of the tab member 50 and stabilize the position of the tab member 50 before welding the tab member 50 to the electrode terminal 40. In addition, the protrusion 222 is coupled to the coupling hole (H) when the position setting of the tab member 50 is completed, thereby preventing the tab member 50 from being separated from the mounting groove 221.

[0036] Figure 4 is a perspective view of the tab member of Figure 2. Referring again to Figure 4, the tab member 50 includes a body portion 51, a first tab 521 and a second tab 522, and a first neck portion 531 and a second neck portion 532.

[0037] The connection structure of the first tab 521 is welded to the positive terminal 41 into two branches and bent, and includes an eleventh connection (C11) extending in the height direction (z-axis direction), followed by a twelfth connection (C12) extending in a direction perpendicular to the first row (R1), and then a thirteenth connection (C13) extending in the first row (R1) direction to connect to the first neck portion 531.

[0038] The connection structure of the second tab 522 is welded to the negative terminal 42 into two branches and bent, and includes a 21st connection (C21) extending in the height direction (z-axis direction), followed by a 22nd connection (C22) extending in a direction perpendicular to the second row (R2), and a 23rd connection (C23) extending in the second row (R2) direction to connect to the second neck portion 532.

[0039] The connection structure of the first tab 521, including the eleventh connection (C11), the twelfth connection (C12), and the thirteenth connection (C13), and the connection structure of the second tab 522, including the twenty-first connection (C21), the twenty-second connection (C22), and the twenty-third connection (C23), are connected to the main body portion 51 over a long distance.

[0040] Therefore, the difference between the overall distance from the connection structure of the first tab 521 through the body portion 51 to the final output end of the tab member 50 and the overall distance from the connection structure of the second tab 522 through the body portion 51 to the final output end of the tab member 50 is minimized. In other words, the voltage difference between the battery cells 10 in the first row (R1) and the battery cells 10 in the second row (R2) can be minimized.

[0041] 3 and 4 again, the main body portion 51 is disposed between the first row (R1) and the second row (R2) of the battery cells 10 and connected in the second direction. The first tab 521 is connected to the positive electrode terminal 41 of the first row (R1). The first tab 521 is connected to the main body portion 51, disposed in the first row (R1), and connected to the first tab 521. The second tab 522 is connected to the negative electrode terminal 42 of the second row (R2). The second tab 522 is connected to the main body portion 51, disposed in the second row (R2), and connected to the second tab 522.

[0042] The first neck portion 531 has a pair of first tabs 521 that electrically connect, and connects the positive terminals 41 of the two battery cells 10 in parallel. The first neck portion 531 avoids the two battery cells 10 arranged in the first row (R1) direction and is arranged between the two battery cells 10. The pair of first tabs 521 are connected to the first neck portion 531, avoid the two battery cells 10 arranged in the first row (R1) direction, and are connected to the positive terminals 41 of each of the two battery cells 10.

[0043] The second neck portion 532 has a pair of second tabs 522 that electrically connect, and connects the negative electrode terminals 42 of the two battery cells 10 in parallel. The second neck portion 532 avoids the two battery cells 10 arranged in the second row (R2) direction and is arranged between the two battery cells 10. The pair of second tabs 522 are connected to the second neck portion 532, avoid the two battery cells 10 arranged in the second row (R2) direction, and are connected to the negative electrode terminals 42 of each of the two battery cells 10.

[0044] The first tab 521 and the first neck portion 531 of the first row (R1) make the current paths of the two battery cells 10 located in the first row (R1) to the body portion 51 the same, so that the voltage difference between the battery cells 10 in the first row (R1) can be minimized.

[0045] The second tab 522 and the second neck portion 532 of the second row (R2) make the current paths of the two battery cells 10 located in the second row (R2) the same up to the body portion 51. Therefore, the voltage difference between the battery cells 10 in the second row (R2) can be minimized.

[0046] The main body 51 is connected to the first neck 531 and the second neck 532, and connects in series two battery cells 10 connected in parallel in the first row (R1) and two battery cells 10 connected in parallel in the second row (R2).

[0047] Therefore, the current of the two battery cells 10 connected in parallel in the first string (R1) flows through the main body 51, and the current of the two battery cells 10 connected in parallel in the second string (R2) flows through the main body 51.

[0048] At this time, since the body portion 51 of the tab member 50 is shared by the first row (R1) and the second row (R2), the voltage difference between the battery cells 10 in the first row (R1) and the second row (R2) can be minimized. Therefore, shortening of the lifespan of the battery cells 10 can be prevented.

[0049] Meanwhile, the tab member 50 further includes a bent portion 55 that is connected to an end of the main body portion 51 disposed between the first row (R1) and the second row (R2) and is formed with a cross section that is convex downward from the side surface. The bent portion 55 extends in a direction at an angle (θ) that is offset from the side surfaces of the two battery cells 10.

[0050] Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. Referring to Fig. 5, the bent portion 55 has a radius of curvature, and a bending start point (BSP) at an upper end of the radius of curvature can be disposed above a diagonal line of the rounded portion (RP) formed at both ends of the battery cell 10 in the axial direction.

[0051] The bent portion 55 is provided in the tab member 50 that connects the battery management system (BMS) 30 and the battery cell 10, and can absorb and mitigate shocks and vibrations transmitted in both directions between the battery management system 30 and the battery cell 10.

[0052] Furthermore, the bent portion 55 forms a gap (G) between itself and the side surface of the battery cell 10. The gap (G) increases the freedom of assembly of the tab member 50 and makes it easier to set the battery cell 10 and the tab member 50 for welding.

[0053] Various embodiments of the present invention will be described below. Descriptions of configurations that are the same as those of the first embodiment and the embodiments already described will be omitted, and only configurations that are different from those of the embodiments will be described.

[0054] Fig. 6 is a plan view of a tab member connecting four battery cells in a secondary battery module according to a second embodiment of the present invention, and Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. Referring to Fig. 6 and Fig. 7, in a tab member 250 applied to a secondary battery module 2 of the second embodiment, a bent portion 55 has a radius of curvature, and an upper end bending start point (BSP2) of the radius of curvature can be disposed above round portions (RP) formed at both ends of the battery cell 10 in the axial direction (the vertical direction in Fig. 7).

[0055] The tab member 250 is connected to the second tab 522 by welding and contacts the battery cell 10 at the side of the bent portion 55, further strengthening the connection between the tab member 250 and the battery cell 10. Therefore, the bent portion 55 is provided on the tab member 250 connecting the battery management system (BMS) 30 and the battery cell 10, and can absorb and reduce shocks and vibrations transmitted in both directions while being more firmly connected to the battery cell 10 side than to the battery management system 30 side.

[0056] 8 is a cross-sectional view of a secondary battery module according to a third embodiment of the present invention. Referring to Fig. 8, in a tab member 350 applied to a secondary battery module 3 of the third embodiment, a bent portion 355 has a radius of curvature, and a top bend start point (BSP) of the radius of curvature may be disposed above a diagonal line of a round portion (RP) formed at both axial ends of a battery cell 10.

[0057] The bent portion 355 is provided on the tab member 350 that connects the battery management system 30 and the battery cell 10, and can absorb and reduce shocks and vibrations transmitted in both directions between the battery management system 30 and the battery cell 10.

[0058] The bent portion 355 further includes a lateral convex surface 56 that is convex toward the side surface of the battery cell 10. The lateral convex surface 56 increases the degree of freedom of assembly of the tab member 350, facilitates setting for welding the battery cell 10 and the tab member 350, and is in contact with the battery cell 10, further strengthening the connection between the tab member 350 and the battery cell 10.

[0059] 9 is a cross-sectional view of a secondary battery module according to a fourth embodiment of the present invention. Referring to FIG 9, in a tab member 450 applied to a secondary battery module 4 of the fourth embodiment, a bent portion 455 is formed with a curved cross section that is convex downward from the side. For example, the curved cross section is formed in a "U" shape.

[0060] The tab member 450 is connected to the second tab 522 by welding, and the side of the bent portion 455 formed with a curved cross section comes into contact with the battery cell 10, further strengthening the connection between the tab member 450 and the battery cell 10. Therefore, the bent portion 455 is provided on the tab member 450 connecting the battery management system (BMS) 30 and the battery cell 10, and can absorb and reduce shocks and vibrations transmitted in both directions while being more firmly connected to the battery cell 10 side than to the battery management system 30 side.

[0061] 10 is a cross-sectional view of a secondary battery module according to a fifth embodiment of the present invention. Referring to FIG. 10, in a tab member 550 applied to a secondary battery module 5 of the fifth embodiment, a bent portion 555 is formed with an angular cross section that is convex downward from the side. As an example, the angular cross section is formed in a "V" shape.

[0062] The tab member 550 is connected to the second tab 522 by welding, and the side of the bent portion 555 formed with an angular cross section comes into contact with the battery cell 10, further strengthening the connection between the tab member 550 and the battery cell 10. Therefore, the bent portion 555 is provided in the tab member 550 connecting the battery management system (BMS) 30 and the battery cell 10, and can absorb and reduce shocks and vibrations transmitted in both directions while being more firmly connected to the battery cell 10 side than to the battery management system 30 side.

[0063] In addition, the variable gap (G2) set between the bent portion 555 and the battery cell 10 increases the degree of freedom in assembling the tab member 450, and facilitates setting the battery cell 10 and the tab member 450 for welding.

[0064] Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, which of course also fall within the scope of the present invention. [Explanation of symbols]

[0065] 1, 2, 3, 4, 5 Secondary battery module 10 Battery Cells 20 Holder 21 Bottom Holder 22 Tab Holder 23 Fastening members 24 Protrusion 25 Joint 30 Battery Management System (BMS) 40 electrode terminal 41 Positive terminal 42 Negative terminal 50 Tab member 51 Main body 54 Output terminal 55 Bend part 56 Lateral convex surface 221 Mounting groove 222 Protrusion 250 Tab member 350 Tab member 355 Bend section 450 Tab member 455 Bend section 521 First Tab 522 2nd Tab 531 First neck section 532 Second neck section 550 Tab member 555 Bend section BSP bending start point BSP2 Bending start point C11 11th Connection C12 12th Connection C13 13th Connection C21 21st Connection C22 22nd Connection C23 23rd Connection G, G2 gap H-bond hole R1 1st row R2 2nd row RP Round Section θ angle

Claims

1. a plurality of battery cells arranged in a first row and a second row parallel to each other; A holder that houses the battery cell; a tab member disposed corresponding to the first row and the second row and welded to an electrode terminal of the battery cell; The tab member includes: a main body portion disposed between the first row and the second row; a first neck portion connected to the body portion, disposed in the first row, and connected to the electrode terminals in the first row by first tabs; a second neck portion connected to the body portion, disposed in the second row, and connected to the electrode terminal in the second row by a second tab.

2. The first neck portion is a pair of the first tabs electrically connected to each other; The pair of first tabs include The battery module according to claim 1 , wherein the electrode terminals of two of the battery cells arranged in the first row direction are welded and electrically connected to each other.

3. The first neck portion is the battery cell is disposed between the two battery cells arranged in the first column direction and avoids the two battery cells arranged in the first column direction; The pair of first tabs include The battery module according to claim 2 , wherein the first neck portion is connected to the electrode terminals of two of the battery cells arranged in the first row direction, and the electrode terminals of the two battery cells are connected to the electrode terminals of the two battery cells.

4. The second neck portion is a pair of the second tabs electrically connected to each other; The pair of second tabs include The battery module according to claim 2 , wherein the electrode terminals of two of the battery cells arranged in the second column direction are welded and electrically connected to each other.

5. The second neck portion is the second column direction is arranged between the two battery cells, while avoiding two battery cells arranged in the second column direction; The pair of second tabs include The battery module according to claim 4 , wherein the second neck portion is connected to the electrode terminals of the two battery cells arranged in the second row direction, and the electrode terminals of the two battery cells are connected to the electrode terminals of the two battery cells, avoiding two battery cells arranged in the second row direction.

6. the battery cell is a cylindrical battery, The axial center of the battery cells arranged in the first row and the axial center of the battery cells arranged in the second row are are arranged to be shifted from each other in a direction intersecting the first row and the second row, The side surfaces of the two battery cells disposed at the ends of the first row and the second row are The battery module according to claim 1 , wherein the first row and the second row are offset from each other at an angle in an arrangement direction.

7. The tab member includes: the body portion disposed between the first row and the second row; and The battery module according to claim 6 , further comprising a bent portion extending in an angular direction offset from a side surface of the two battery cells, connected to an end of the body portion, and formed with a cross section that is convex downward from the side surface.

8. The bent portion has a radius of curvature, The upper end bending start point of the radius of curvature is The battery module according to claim 7 , which is disposed above a diagonal line of rounded portions formed at both axial ends of the battery cells.

9. The bent portion has a radius of curvature, The upper end bending start point of the radius of curvature is The battery module according to claim 7 , which is disposed above rounded portions formed on both axial ends of the battery cells.

10. The battery module according to claim 7 , wherein the bent portion further includes a lateral convex surface that is convex toward the side surface of the battery cell.

11. The battery module according to claim 7 , wherein the bent portion is formed with a curved cross section (U) that is convex downward from the side surface.

12. The battery module according to claim 7 , wherein the bent portion is formed with an angular cross section (V) that is convex downward from the side surface.

13. The first tab connection structure includes: an eleventh connection, which is welded to the electrode terminal in two pieces and is bent to extend in the height direction; a twelfth connection extending perpendicular to the first row; and The battery module of claim 1 , further comprising a thirteenth connector extending in the first row direction to subsequently connect to the first neck portion.

14. The second tab connection structure includes: A 21st connection is welded to the electrode terminal in two parts and bent to extend in the height direction; a second connection extending perpendicular to the second row; and The battery module of claim 13 , further comprising a second connector extending in the second row direction to subsequently connect to the second neck portion.

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