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

[0006] , , , ,

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

Background Art

[0002] A rechargeable battery is a battery that repeats charging and discharging, unlike a primary battery. A small-sized rechargeable battery is used for portable small electronic devices such as mobile phones, notebook computers, and camcorders. A large-capacity and high-density rechargeable battery is used as a power source for driving a motor of a hybrid vehicle and an electric vehicle or for energy storage.

[0003] A rechargeable battery requires a relatively high energy density and can be used as a secondary battery module including a plurality of battery cells connected in series and / or in parallel so that, for example, a motor of a hybrid vehicle can be driven. For example, a secondary battery module is formed by connecting electrode terminals of a plurality of battery cells configured in a number corresponding to a desired amount of electric power to each other in order to realize a relatively high-output secondary battery module (for example, an electric vehicle).

[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 in parallel with tabs. Since the voltage and current of a secondary battery module are high depending on the usage conditions of a consumer, the secondary battery module includes tabs for connecting battery cells and a battery management system connected to the tabs.

[0005] At this time, since a plurality of battery cells are connected to one tab, a voltage difference may occur between the battery cells due to discharge. The voltage difference between the battery cells may reduce the life of the battery cells.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One embodiment of the present invention provides a secondary battery module that minimizes the voltage difference between multiple 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 housing the battery cells, and tab members arranged corresponding to the first row and the second row and welded to the electrode terminals of the battery cells, wherein the tab members include a main body portion arranged between the first row and the second row, a first neck portion connected to the main body portion and arranged in the first row and connected to the electrode terminals of the first row by a first tab, and a second neck portion connected to the main body portion and arranged in the second row and connected to the electrode terminals of the second row by a second tab.

[0008] The first neck portion comprises a pair of electrically connected first tabs, the pair of first tabs being welded to the electrode terminals of each of the two battery cells arranged in the first row direction and electrically connected. The first neck portion is positioned 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 being connected to the electrode terminals of each of the two battery cells.

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

[0010] The second neck portion is positioned between the two battery cells, avoiding the 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 and second rows, and the sides of two battery cells arranged at the ends of the first and second rows may have the offset angle in the direction of arrangement of the first and second rows.

[0012] The tab member may include a main body portion positioned between the first and second rows, and a bent portion that extends in the offset angular direction from the sides of the two battery cells, is connected to the end of the main body portion, and has a downwardly convex cross-section from the side.

[0013] The bent portion has a radius of curvature, and the upper end of the radius of curvature, where the bend begins, can be positioned above the diagonal of the rounded portion formed at both axial ends of the battery cell.

[0014] The bent portion has a radius of curvature, and the upper end of the radius of curvature, where the bend begins, can be positioned above the 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 the side surface of the battery cell.

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

[0017] The bent portion can be formed with a cross-section (V) that is convex downward from the side surface.

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

[0019] The connection structure of the second tab is welded to the electrode terminal in two branches and bent, including a second 1 connection extending in the height direction, a second 2 connection extending in a direction perpendicular to the second row, and a second 3 connection extending in the second row direction so as to be connected to the second neck portion.

Advantages of the Invention

[0020] The secondary battery module of one embodiment includes a tab member, a main body portion, a first neck portion, a second neck portion, and a first row of battery cells including a first tab and a second tab, and is connected to the electrode terminals of the second row of battery cells, so that the main body portion of the tab member can be shared. Therefore, the voltage difference between a plurality of battery cells can be minimized. Therefore, shortening of the life of the battery cell can be prevented.

Brief Description of the Drawings

[0021] [Figure 1] It is an exploded perspective view of a secondary battery module according to a first embodiment of the present invention. [Figure 2] It is a plan view of a secondary battery module according to a first embodiment of the present invention. [Figure 3] It is a plan view of a tab member connecting four battery cells in FIG. 2. [Figure 4] It is a perspective view of the tab member in FIG. 2. [Figure 5] It is a cross-sectional view taken along the line V-V in FIG. 3. [Figure 6] In a secondary battery module according to a second embodiment of the present invention, it is a plan view of a tab member connecting four battery cells. [Figure 7] It is a cross-sectional view taken along the line VII-VII in FIG. 6. [Figure 8] It is a cross-sectional view of a secondary battery module according to a third embodiment of the present invention. [Figure 9] It is a cross-sectional view of a secondary battery module according to a fourth embodiment of the present invention. [Figure 10] It is a cross-sectional view of a secondary battery module according to a fifth embodiment of the present invention. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those with ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention can be implemented in a variety of different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts that are not necessary for explanation have been omitted from the drawings, and the same or similar components are denoted by the same reference numerals throughout the specification.

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

[0024] Multiple battery cells 10 consist of cylindrical secondary batteries, each of which has electrode terminals 40 at both axial ends. Specifically, the electrode terminals 40 include a positive electrode terminal 41 and a negative electrode terminal 42, which are provided at both axial ends of each battery cell 10.

[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 inside 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 connected to each other in a third direction (z-axis direction) intersecting the second direction and firmly fastened together by a fastening member 23.

[0026] In the configuration shown in Figure 1, the bottom holder 21 accommodates the lower part of the battery cell 10, and the tab holder 22 accommodates the upper part of the battery cell 10. In this configuration, the bottom holder 21 and the tab holder 22 are fastened together by the fastening member 23.

[0027] Furthermore, the bottom holder 21 and the tab holder 22 can be further connected by a snap-fit ​​structure consisting of a connecting portion 24 provided on the outside of the bottom holder 21 and a projection 25 provided on the outside of the tab holder 22 that corresponds to the connecting portion 24.

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

[0029] For example, in the first row (R1), the positive terminal 41 is positioned at the top and the negative terminal 42 is positioned at the bottom. In the second row (R2), the positive terminal 41 is positioned at the bottom and the negative terminal 42 is positioned 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 offset from each other in a direction that intersects the first row (R1) and the second row (R2). Therefore, it is possible to prevent the cylindrical battery cells 10 from being arranged adjacent to each other.

[0031] In other words, the battery cells 10 located in the second row (R2) are shifted in the second direction (y-axis direction) relative to the battery cells 10 located in the first row (R1). Therefore, the sides of the two battery cells 10 located at the ends of the first row (R1) and the second row (R2) have an angle (θ) that is offset in the direction of the arrangement of the first row (R1) and the second row (R2).

[0032] As an example, the tab member 50 can be formed from nickel material and 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 can be formed by punching out thin sheet material.

[0033] As an example, the battery management system (BMS) 30 can be installed on the sides of the bottom holder 21 and the tab holder 22. Each tab member 50 has an output terminal 54 on one side in the first direction (x-axis direction), and is electrically connected to the battery management system (BMS) 30 at the output terminal 54.

[0034] The tab member 50 is positioned in the mounting grooves 221 of the bottom holder 21 and the tab holder 22, and connects to the corresponding electrode terminals 40, etc. A projection 222 is provided on one side of the mounting groove 221, and is coupled to the 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 its position before welding it to the electrode terminal 40. In addition, the protrusion 222 connects to the coupling hole (H) when the position setting of the tab member 50 is complete, preventing the tab member 50 from separating 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 main body 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 includes a 11th connection (C11) that is welded to the positive terminal 41 in two branches and bent, extending in the height direction (z-axis direction), followed by a 12th connection (C12) that extends in a direction perpendicular to the first row (R1), and then a 13th connection (C13) that extends in the direction of the first row (R1) to connect to the first neck portion 531.

[0038] The connection structure of the second tab 522 includes a 21st connection (C21) welded to the negative terminal 42 in two branches and bent, 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 then a 23rd connection (C23) extending in the direction of the second row (R2) to connect to the second neck portion 532.

[0039] The connection structure of the first tab 521, which includes the 11th connection (C11), the 12th connection (C12), and the 13th connection (C13), and the connection structure of the second tab 522, which includes the 21st connection (C21), the 22nd connection (C22), and the 23rd connection (C23), are connected to the main body 51 via a long distance.

[0040] Therefore, the connection structure of the first tab 521 minimizes the difference between the total distance from the main body 51 to the final output end of the tab member 50 and the connection structure of the second tab 522 minimizes the difference between the total distance from the main body 51 to the final output end of the tab member 50. 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] Referring again to Figures 3 and 4, the main body 51 is positioned between the first row (R1) and the second row (R2) of the battery cell 10 and connected in the second direction. The first tab 521 is connected to the positive terminal 41 of the first row (R1). The first tab 521 is connected to the main body 51, positioned in the first row (R1), and connected to the first tab 521. The second tab 522 is connected to the negative terminal 42 of the second row (R2). The second tab 522 is connected to the main body 51, positioned in the second row (R2), and connected to the second tab 522.

[0042] The first neck portion 531 includes a pair of electrically connected first tabs 521 that connect the positive terminals 41 of the two battery cells 10 in parallel. The first neck portion 531 is positioned between the two battery cells 10, avoiding the two battery cells 10 arranged in the first row (R1) direction. The pair of first tabs 521 are connected to the first neck portion 531, avoiding 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 includes a pair of electrically connected second tabs 522, which connect the negative terminals 42 of the two battery cells 10 in parallel. The second neck portion 532 is positioned between the two battery cells 10, avoiding the two battery cells 10 arranged in the second row (R2) direction. The pair of second tabs 522 are connected to the second neck portion 532, avoiding the two battery cells 10 arranged in the second row (R2) direction, and are connected to the negative 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 path of the two battery cells 10 located in the first row (R1) the same up to the main body portion 51. Therefore, the voltage difference between the battery cells 10 in the first row (R1) can be minimized.

[0045] The second tab 522 and second neck portion 532 of the second row (R2) make the current path of the two battery cells 10 located in the second row (R2) the same up to the main 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 section 531 and the second neck section 532, and connects 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) in series.

[0047] Therefore, the current from the two battery cells 10 connected in parallel in the first row (R1) flows to the main body 51, and the current from the two battery cells 10 connected in parallel in the second row (R2) also flows to the main body 51.

[0048] In this case, the main body 51 of the tab member 50 is shared by the first row (R1) and the second row (R2), so the voltage difference between the battery cells 10 in the first row (R1) and the second row (R2) can be minimized. Therefore, it is possible to prevent a shortening of the battery cell lifespan 10.

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

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

[0051] The bent portion 55 is provided on 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 degree of freedom in assembly of the tab member 50 and facilitates setting up for welding the battery cell 10 and the tab member 50.

[0053] The following describes various embodiments of the present invention. Descriptions of configurations identical to those of the first embodiment and the embodiments already described will be omitted, and descriptions of configurations that differ from each other will be provided.

[0054] Figure 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 Figure 7 is a cross-sectional view taken along the line VII-VII in Figure 6. Referring to Figures 6 and 7, in the tab member 250 applied to the secondary battery module 2 of the second embodiment, the bent portion 55 has a radius of curvature, and the upper end bending start point (BSP2) of the radius of curvature can be positioned above the rounded portions (RP) formed at both ends of the battery cell 10 in the axial direction (up and down direction in Figure 7).

[0055] The tab member 250 is welded to the second tab 522 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. Thus, 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 mitigate 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] Figure 8 is a cross-sectional view of a secondary battery module according to a third embodiment of the present invention. Referring to Figure 8, in the tab member 350 applied to the secondary battery module 3 of the third embodiment, the bent portion 355 has a radius of curvature, and the upper end bending start point (BSP) of the radius of curvature can be positioned above the diagonal of the rounded portion (RP) formed at both axial ends of the 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 mitigate shocks and vibrations transmitted in both directions between the battery management system 30 and the battery cell 10.

[0058] Furthermore, 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 for the tab member 350, facilitates setting up for welding the battery cell 10 and the tab member 350, and also contacts the battery cell 10, making the connection between the tab member 350 and the battery cell 10 even more robust.

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

[0060] The tab member 450 is welded to the second tab 522 and contacts the battery cell 10 at the side of the bent portion 455, which is formed in a curved cross section, further strengthening the connection between the tab member 450 and the battery cell 10. Thus, 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 mitigate 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] Figure 10 is a cross-sectional view of a secondary battery module according to a fifth embodiment of the present invention. Referring to Figure 10, in the tab member 550 applied to the secondary battery module 5 of the fifth embodiment, the bent portion 555 is formed with a downwardly convex, angular cross-section from the side. As an example, the angular cross-section is formed in the shape of a "V".

[0062] The tab member 550 is welded to the second tab 522 and contacts the battery cell 10 at the side of the bent portion 555, which has an angular cross-section, further strengthening the connection between the tab member 550 and the battery cell 10. Thus, the bent portion 555 is provided on the tab member 550 connecting the battery management system (BMS) 30 and the battery cell 10, and can absorb and mitigate 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] Furthermore, the variable gap (G2) set between the bent portion 555 and the battery cell 10 increases the degree of freedom in assembly of the tab member 450 and facilitates setting up for welding the battery cell 10 and the tab member 450.

[0064] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, description of the invention, and accompanying drawings, and these also naturally fall within the scope of the present invention. [Explanation of Symbols]

[0065] 1, 2, 3, 4, 5 Secondary battery modules 10 battery cells 20 holders 21 Bottom Holder 22 Tab Holders 23 Fastening members 24 Protrusion 25 Joint 30. Battery Management System (BMS) 40 electrode terminal 41 Positive terminal 42 Negative terminal 50 Tab members 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 Tab 1 522 Second 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 holes R1 1st row R2 2nd row RP Round Section θ angle

Claims

1. Multiple battery cells arranged in a first and second row parallel to each other, A holder for housing the aforementioned battery cell, Includes tab members arranged corresponding to the first and second rows and welded to the electrode terminals of the battery cell, The tab member is A main body portion positioned between the first row and the second row, A first neck portion is connected to the main body, arranged in the first row, and connected to the electrode terminals of the first row by a first tab, It includes 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 by a second tab, The first neck portion and the second neck portion protrude outward from the main body, and the first tab and the second tab protrude in directions opposite to each other. Battery module.

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

3. The first neck portion is, Displaced between the two battery cells arranged in the first row direction, The pair of first tabs are The battery module according to claim 2, which is connected to the first neck portion and connected to the electrode terminals of each of the two battery cells.

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

5. The second neck portion is, Displaced between the two battery cells arranged in the second row direction, The pair of the second tabs are The battery module according to claim 4, which is connected to the second neck portion and to the electrode terminals of each of the two battery cells arranged in the second row direction.

6. The aforementioned battery cell is a cylindrical battery, The axial center of the battery cell arranged in the first row and the axial center of the battery cell arranged in the second row are, The first and second columns are arranged offset from each other in a direction that intersects them, The sides of the two battery cells located at the ends of the first and second rows are, The battery module according to claim 1, wherein the first row and the second row are offset from each other in the arrangement direction.

7. The tab member is The main body portion, which is positioned between the first row and the second row, and The battery module according to claim 6, comprising a bent portion that extends in a direction intersecting the sides of the two battery cells, is connected to the end of the main body, and has a downwardly convex cross-section from the side.

8. The bent portion has a radius of curvature, The upper end of the radius of curvature where the bend begins is, The battery module according to claim 7, which is positioned above the diagonal of the rounded portions formed at both axial ends of the battery cell.

9. The bent portion has a radius of curvature, The upper end of the radius of curvature where the bend begins is, The battery module according to claim 7, which is positioned above the rounded portions formed at both axial ends of the battery cell.

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 downwardly convex curved cross section (U) from the side surface.

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

13. The connection structure of the first tab is, Two 11th connections are welded to the electrode terminals and bent to extend in the height direction, Next, a twelfth connection extending in a direction perpendicular to the first row, and The battery module according to claim 1, further comprising a thirteenth connection extending in the direction of the first row so as to connect to the first neck portion.

14. The connection structure of the second tab is, Two 21 connections are welded to the electrode terminals and bent to extend in the height direction. Next, a 22nd connection extending in a direction perpendicular to the second row, and The battery module according to claim 13, further comprising a second connection extending in the direction of the second row so as to connect to the second neck portion.

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