Battery module and manufacturing method for the same

Abstract

A battery module includes at least one battery cell array including a cell frame and a plurality of battery cells, each battery cell having electrode terminals disposed at both ends of each battery cell and oriented toward the same direction, the plurality of battery cells being disposed in a lateral direction when mounted in the cell frame; and a plurality of connection members attached to the electrode terminals of a respective battery cell of the at least one battery cell array at an upper portion, a lower portion, or both of the at least one battery cell array, wherein each connection member is a metal plate having at least three vertical slits that are spaced apart from each other and a horizontal slit that crosses at least one of the vertical slits.

Claims

1. A battery module, comprising: at least one battery cell array including a cell frame and a plurality of battery cells, each battery cell having electrode terminals disposed at both ends of each battery cell and oriented toward the same direction, the plurality of battery cells being disposed in a lateral direction when mounted in the cell frame; and a plurality of connection members attached to the electrode terminals of a respective battery cell of the at least one battery cell array at an upper portion, a lower portion, or both of the at least one battery cell array, wherein each connection member is a metal plate having at least three vertical slits that are spaced apart from each other and a horizontal slit that crosses at least one of the vertical slits, wherein the at least three vertical slits include: a first slit connected to one end of the horizontal slit; a second slit connected to another end of the horizontal slit; and a third slit which crosses the horizontal slit between the first slit and the second slit, and wherein a length of the third slit is larger than 100% and smaller than 130% of a length of the first slit or a length the second slit, wherein each connection member includes two or more resistance welding units set between adjacent vertical slits among the at least three vertical slits, wherein each of the two or more resistance welding units is partitioned into a first welding unit in an upper direction and a second welding unit in a lower direction with respect to the horizontal slit, wherein the two or more resistance welding units set in each connection member are resistively welded to the electrode terminals of the respective battery cell, and wherein each connection member includes a current application path along one of the at least three vertical slits configured so that the current application path taken by a reactive current from the first welding unit to the second welding unit is extended along the one of the at least three vertical slits.

2. The battery module of claim 1, wherein the metal plate includes an alloy of copper as a first material and at least one metal selected from a group consisting of zinc, nickel, aluminum, platinum, lead, tin, and stainless steel as a second material.

3. The battery module of claim 1, wherein the third slit is perpendicular to the horizontal slit.

4. The battery module of claim 1, wherein the third slit forms an angle of 20 degrees to 160 degrees with respect to the horizontal slit.

5. The battery module of claim 1, wherein the first slit and the second slit are perpendicular to the horizontal slit.

6. The battery module of claim 1, wherein: the first slit and the second slit have a wedge shape curved with respect to a portion connected to the horizontal slit and an internal angle of the wedge shape is 120 degrees or larger and less than 180 degrees.

7. The battery module of claim 1, wherein the first slit and the second slit are connected to the horizontal slit with a curved line on plan view.

8. The battery module of claim 1, wherein each battery cell is a cylindrical battery cell comprising: a cylindrical metal can that is closed and sealed as a top cap assembly; an electrode assembly and an electrolytic solution embedded in the cylindrical metal can.

9. A method of manufacturing the battery module of claim 1, the method comprising: pressurizing a connection member among a plurality of connection members to an electrode terminal of a battery cell among the plurality of battery cells; initially bonding the two or more resistance welding units and the electrode terminals by disposing welding rods in the first welding unit and the second welding unit of a resistance welding unit adjacent to a first slit among the at least three vertical slits and forming an active current which passes through an electrode terminal among the electrode terminals between the welding rods; and disposing the welding rods in the first welding unit and the second welding unit of the resistance welding unit adjacent to a second slit among the at least three vertical slits and forming the active current which passes through the electrode terminal between the welding rods to additionally bond the resistance welding unit and the electrode terminal.

10. The method of claim 9, wherein in the initial bonding, a reactive current which does not pass through the electrode terminal is additionally formed between the welding rods, and wherein the reactive current is applied to the second welding unit along a periphery of the first slit of the connection member from the first welding unit.

11. The method of claim 9, wherein in the additional bonding, a reactive current which does not pass through the electrode terminal is additionally formed between the welding rods, wherein the reactive current is applied to the second welding unit along a periphery of a third slit among the at least three vertical slits of the connection member from the first welding unit, and wherein at the time of current application, the reactive current passes through the electrode terminal bonded in the initial bonding.

12. The battery module of claim 1, wherein the third slit is not parallel to the first slit and the second slit.

13. The battery module of claim 1, wherein the first slit is not parallel to the second slit.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a battery module according to the related art.

(2) FIGS. 2 to 4 are a photograph and schematic views of a bonding type between a connection member and an electrode terminal of a battery cell using resistance welding.

(3) FIG. 5 is a photograph of a connection member in which a defect according to resistance welding is caused.

(4) FIG. 6 is a schematic view of a battery module according to an exemplary embodiment of the present invention.

(5) FIG. 7 is a plan view of a connection member which configures a battery module of FIG. 6.

(6) FIG. 8 is a schematic view illustrating a welding method of a connection member of FIGS. 6 and 7.

(7) FIG. 9 is a plan view of a connection member according to another exemplary embodiment of the present invention.

MODE FOR INVENTION

(8) Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in description of the present invention, description for known functions or configurations will be omitted to clarify the gist of the present invention.

(9) In order to clearly describe the present invention, parts which are not related to the description will be omitted and like reference numerals designate like elements throughout the specification. Further, the size and the thickness of components illustrated in the drawings are optionally illustrated for better understanding and ease of description and the present invention is not necessarily limited to those illustrated in the drawings.

(10) FIG. 6 illustrates a schematic view of a battery module according to an exemplary embodiment of the present invention and FIG. 7 illustrates a plan view of a connection member which configures a battery module of FIG. 6.

(11) First, referring to FIG. 6, a battery module 100 includes a battery cell arrays 105, a plurality of battery cells 110, a cell frame 120, and a plurality of connection members 200.

(12) The battery cell arrays 105 are configured such that the plurality of battery cells 110 in which electrode terminals (20 in FIG. 2) located at both ends of a cylindrical battery cell are located toward the same direction is disposed in a lateral direction to be mounted in the cell frame 120.

(13) Each of the connection members 200 is a bus bar which is bonded to the electrode terminal 111 of each battery cell 110 of the battery cell arrays 105 and is connected to the battery cell arrays 105 so as to connect one or two battery cells 110 to each other.

(14) Further, each of the connection members 200 is an electro-conductive metal plate and for example, is a composite material formed by alloying copper having a low resistance with an electro-conductive metal, for example, at least one selected from a group consisting of zinc, nickel, aluminum, platinum, lead, tin, and stainless steel.

(15) As an example, the connection member 200 may be an alloy material containing copper of 98 wt %, nickel of 1 wt % of nickel, and tin of 1 wt %.

(16) As another example, the connection member 200 may be an alloy material containing copper of 97 wt % and tin of 3 wt %.

(17) In contrast, the connection member 200 may be an alloy material containing copper of 90 wt % and zinc of 10 wt %.

(18) However, these are examples selected in the scope of the present invention and the connection member 200 of the present invention is not limited thereto.

(19) Hereinafter, a shape of the connection member 200 coupled to one electrode terminal 111 of the battery cell 110 will be described in more detail with reference to FIG. 7.

(20) In the connection member 200, a plurality of slits 210, 220, 230, and 240 in a vertical direction and a horizontal direction is perforated. Particularly, the horizontal slit 240 is perforated in the connection member 200 so as to connect the vertical slits 210, 220, and 230 and the vertical slits 210, 220, and 230 are perforated in the connection member 200 to be spaced apart from each other.

(21) The connection member 200 also includes a first resistance welding unit 310 and a second resistance welding unit 320 which are set between adjacent vertical slits among the vertical slits 210, 220, and 230.

(22) The first resistance welding unit 310 and the second resistance welding unit 320 are partitioned into first welding units 311 and 321 in an upper direction and second welding units 312 and 322 in a lower direction with respect to the horizontal slit 240.

(23) Therefore, in the connection member 200, the first resistance welding unit 310 and the second resistance welding unit 320 which are independent welded portions are resistively welded to the electrode terminal 111 of the battery cell 110.

(24) Therefore, the connection member 200 is double-bonded with the electrode terminal 111 of the battery cell 110 and the battery module 100 forms a stable connection by the double-bonding of the connection member 200 and the electrode terminal 20 of the battery cell 110 so that a possibility of defects such as deformation and breakage of the bonded shape between the electrode terminal 20 and the connection member 200 due to the external force such as vibration and impact is significantly reduced.

(25) The vertical slits 210, 220, and 230 include a first slit 210 connected to one end of the horizontal slit 240, a second slit 220 connected to the other end of the horizontal slit 240, and a third slit 230 which crosses the horizontal slit 240 between the first slit 210 and the second slit 220.

(26) In this case, the third slit 230 is perpendicular to the horizontal slit 240.

(27) The first resistance welding unit 310 is set between the first slit 210 and the third slit 230.

(28) The second resistance welding unit 320 is set between the second slit 220 and the third slit 230.

(29) The first resistance welding unit 310 is partitioned into a first welding unit 311 and a second welding unit 312 with the horizontal slit 240 therebetween.

(30) The second resistance welding unit 320 is partitioned into a first welding unit 311 and a second welding unit 312 with the horizontal slit 240 therebetween.

(31) The third slit 230 is 10% longer than the first slit 210 or the second slit 220.

(32) The first slit 210 and the second slit 220 have the same length and have a wedge shape curved at a predetermined angle t with respect to a portion connected to the horizontal slit 240. An internal angle of the wedge is approximately 120 degrees.

(33) An advantage obtained by the wedge shape of the first slit 210 and the second slit 220 will be described.

(34) The first resistance welding unit 310 formed between the wedge shaped first slit 210 and the third slit 230 has a wide area as compared with a first slit 210 having a straight line shape.

(35) This means that a contact area for the electrode terminal 111 of the battery cell 110 is wide and further means that an electric conductive efficiency of the electrode terminal 111 and the connection member 200 is excellent. The same advantage is obtained by the second resistance welding unit 320 formed between the second slit 220 and the third slit 230.

(36) In the meantime, FIG. 8 illustrates a schematic view of a welding method of the connection member 200 of FIGS. 6 and 7.

(37) Referring to FIG. 8 and FIGS. 6 and 7 together, a structural advantage of the connection member according to the present invention and a method for welding the connection member to the electrode terminal will be described.

(38) First, an advantage of the connection member 200 is that when the first slit 210, second slit 220 and third slit 230 in the vertical direction are connected to the horizontal slit 240, the welded portion is set as independent two units of the first resistance welding unit 310 and the second resistance welding unit 320 and thus at the time of resistance welding, the application path of the reactive current C2 is blocked by the first slit 210, the second slit 220 and the third slit 230 to be detoured.

(39) Particularly, when a voltage is applied to welding rods after disposing and pressurizing welding rods in the first welding unit 311 and the second welding unit 312 in the first resistance welding unit 310 adjacent to the first slit 210, the active current C1 which is applied to the second welding unit 312 via the electrode terminal 20 from the first welding unit 311 is formed.

(40) That is, even though the first welding unit 311 and the second welding unit 312 are divided by the horizontal slit 240, the first welding unit 311 and the second welding unit 312 are closely adhered to the electrode terminal 111 so that the active current C1 which is converted into an actual thermal energy is directly applied from the first welding unit 311 to the second welding unit 312.

(41) The first welding unit 311 and the second welding unit 312 are fused by the resistance formed during this process and the heat generated thereby so that the first resistance welding unit 310 of the connection member 200, more specifically, the first welding unit 311 and the second welding unit 312 are bonded to the electrode terminal 111.

(42) However, during this process, a reactive current C2 which does not pass through the electrode terminal 111 is additionally formed between the welding rods.

(43) Here, the entire connection member 200 is not closely adhered to the electrode terminal 111 except for the first welding unit 311 and the second welding unit 312 so that the interface resistance for the electrode terminal 111 is formed to be high in the entire connection member 200.

(44) Therefore, the reactive current C2 is applied only through the connection member 200 having a low resistance except for the interface having a relatively high resistance.

(45) However, in the connection member 200 according to the present invention, since the first welding unit 311 of the first resistance welding unit 310 is blocked by the horizontal slit 240, the first slit 210, and the third slit 230, the reactive current C2 is detoured along a periphery of the first slit 210 to be applied to the second welding unit 312.

(46) For this reason, at the time of resistance welding, the active current C1 and the reactive current C2 are not concentrated to the first resistance welding unit 310 and the periphery thereof. In other words, an overcurrent in which the reactive current C2 is included in the active current C1 is not formed in the first resistance welding unit 310 which is an actual welded portion, so that the problems such as destruction, fracture of the connection member 200 and deterioration of welding quality due to the overcurrent may be solved. The above-described process is defined as an initial bonding step.

(47) Next, in the second resistance welding unit 320 adjacent to the third slit 230, when the voltage is applied to the welding rods after disposing and pressuring the welding rods in the first welding unit 321 and the second welding unit 322, the active current C1 which is applied to the second welding unit 322 via the electrode terminal 111 from the first welding unit 321 of the second resistance welding unit is formed.

(48) The first welding unit 321 and the second welding unit 322 of the second resistance welding unit 320 are fused by the resistance formed during this process and the heat generated thereby so that the second resistance welding unit 320 of the connection member 200 is additionally bonded to the electrode terminal 111. The above-described process is defined as an additional bonding step.

(49) That is, since the connection member 200 according to the present invention is bonded to the electrode terminal 111 in respective resistance welding units 310 and 320 set in this unit, the double bonding to the electrode terminal 111 may be established.

(50) However, since the first resistance welding unit 310 and the electrode terminal 111 which have been already bonded is substantially integrated to each other, during the welding process of the second resistance welding unit 320, the reactive current may be applied through the first resistance welding unit 310 and the electrode terminal 111 which have been already bonded.

(51) Therefore, the interface resistance is formed to be relatively high in the entire connection member 200 except for the already bonded first resistance welding unit 310 and the electrode terminal 20 and the first welding unit 321 and the second welding unit 322 of the second resistance welding unit 320.

(52) Accordingly, when the second resistance welding unit 320 is welded, the reactive current C2 is applied through the connection member 200 having a low resistance or the first resistance welding unit 310 which is already bonded and does not have substantially an interface resistance, except for the interface having a relatively high resistance.

(53) However, in the connection member 200 according to the present invention, since the third slit 230 partitions the second resistance welding unit 320 and the first resistance welding unit 310, the reactive current C2 is detoured along the periphery of the third slit 230 and then applied to the second welding unit 322 of the second resistance welding unit 320 through the first welding unit 311 and the second welding unit 312 of the first resistance welding unit 310.

(54) For this reason, even though the resistance welding is additionally performed, the active current C1 and the reactive current C2 are not concentrated to the second resistance welding unit 320 and the periphery thereof. In other words, even though the resistance welding is performed two times, the problems in that the overcurrent is generated and the connection member 200 is broken or the welding quality is deteriorated due to the overcurrent may be solved.

(55) In the meantime, FIG. 9 illustrates a plan view of a connection member according to another exemplary embodiment of the present invention.

(56) Referring to FIG. 9, a connection member 400 includes a first slit 410, a second slit 420, and a third slit 430 which are vertical slits and a horizontal slit 440. The first slit 410 is connected to one end of the horizontal slit 440. The second slit 420 is connected to the other end of the horizontal slit 440. The third slit 430 which crosses the horizontal slit 440 may be perforated between the first slit 410 and the second slit 220.

(57) A first resistance welding unit 401 is set between the first slit 410 and the third slit 430. A second resistance welding unit 402 is set between the second slit 420 and the third slit 430. The third slit 430 is 10% longer than the first slit 410 or the second slit 420.

(58) The first slit 410 and the second slit 420 may have a round shape having a curved line in the plan view.

(59) The first slit 410 and the second slit 420 having the structure as described above have an advantage in that a current application distance is longer than that of the straight line.

(60) The third slit 430 is approximately 10% longer than the first slit 410 or the second slit 420 and forms an angle of approximately 110 degrees with respect to the horizontal slit 440 to be perforated in a straight line.

(61) According to this structure, the third slit 430 is oblique with respect to the horizontal slit 440 so that the application path of the reactive current which detours to the third slit 430 may be relatively extended.

(62) Although specific examples of the present invention have been described and illustrated, the present invention is not limited to the described example and it is obvious to those skilled in the art that various changes and modification can be made without departing from the spirit and scope of the present invention. Therefore, the changes and modifications are not construed individually from the technical spirit or viewpoint of the present invention and it is intended that the modified embodiments fall into the scope of the claims of the present invention.

(63) While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

INDUSTRIAL APPLICABILITY

(64) As described above, an advantage of the battery module according to the present invention is that the connection member includes three or more vertical slits and a horizontal slit connecting three slits.

(65) The connection member is bonded to the electrode terminal through two times or more resistance welding to form an excellent welding quality and bonding shape. As a result, in the battery module of the present invention including the connection member, the electrical connection structure between the battery cell and the connection member may be stably maintained despite the external force such as vibration or impact, based on the structure in which the electrode terminal of the battery cell and the connection member are bonded two times or more.

(66) Further, in the battery module manufacturing method according to the present invention, resistance welding is performed on the resistance welding units set in the connection member two times or more so that the connection member and the electrode terminal are double-bonded to implement a stable bonding structure. Further, during the welding process of the resistance welding units, the application path of the reactive current is blocked by the first slit and the third slit which are vertical slits to be detoured so that the destruction of the connection due to the overcurrent may be prevented despite two times of resistance welding.