Rechargeable battery pack

Abstract

Provided is a rechargeable battery pack. The rechargeable battery pack comprises busbars electrically connecting a plurality of battery cells, a first connection part disposed adjacent to the busbars, and fuse assemblies each configured such that opposite ends of a fuse are respectively connected to a busbar and the first connection part so as to transmit a signal sensed from the busbar to the first connection part, wherein each fuse assembly comprises: a first tab and a second tab spaced apart from each other and respectively connected to the busbar side and the first connection part side; and a second connection part electrically connecting the first tab and the second tab via the fuse interposed therebetween.

Description

secondary battery pack

[0001] The present invention relates to a secondary battery pack, and more specifically, to a secondary battery pack in which a busbar is connected to a flexible flat cable (FFC).

[0002] Unlike primary batteries, rechargeable batteries are batteries that undergo repeated charging and discharging. Small-capacity rechargeable batteries are used in portable small electronic devices such as mobile phones, laptop computers, and camcorders.

[0003] Large-capacity and high-density secondary batteries are used as power sources for driving motors in hybrid and electric vehicles or for energy storage. Secondary batteries can be used by forming a secondary battery module comprising multiple battery cells connected in series and / or parallel, so as to drive a motor in a hybrid vehicle, for example, which requires relatively high energy density.

[0004] The secondary battery module is equipped with a flexible printed circuit (FPC) that detects the voltage of the busbar and transmits the detection signal to check the charge status of the battery cells. In the FPC detection structure, the FPC is soldered to a separate tab, and the tab is welded to an aluminum (Al) busbar.

[0005] One embodiment of the present invention provides a secondary battery pack that applies a flexible flat cable (FFC) to detect voltage and transmit the detection signal to check the charge status of the battery cells through a busbar connecting the battery cells.

[0006] A secondary battery pack according to one embodiment of the present invention comprises a busbar electrically connecting a plurality of battery cells, a first connection portion disposed adjacent to the busbar, and a fuse assembly in which both sides of a fuse are respectively connected to the busbar side and the first connection portion side to send a signal detected by the busbar to the first connection portion, wherein the fuse assembly comprises a first tab and a second tab spaced apart from each other and respectively connected to the busbar and the first connection portion, and a second connection portion electrically connecting the first tab and the second tab via the fuse.

[0007] The first tab above can be connected to the busbar by welding.

[0008] The first connecting portion is formed of a flexible flat cable (FFC), and the FFC may include a first strip to an n-th strip that extends in a first direction and has a gap in a second direction intersecting the first direction, and forms a circuit that transmits a detected signal.

[0009] The second tab may have a width formed in the first direction, a length formed in the second direction corresponding to the FFC, and an area set by the width and the length.

[0010] The second tab may be provided with first through holes to n through holes corresponding to each of the first strip to the nth strip.

[0011] One of the first to nth strips can be electrically connected to the second tab by solder supplied to the exposed and corresponding first to nth through holes.

[0012] Each of the first through holes to the nth through holes is spaced apart along the elongation direction of the corresponding strip, and can supply solder at a plurality of points of the strip that are correspondingly exposed.

[0013] The second tab above can be surface-mounted with solder between the correspondingly exposed strips.

[0014] The strips among the first to nth strips that are not connected by solder can be electrically insulated from the second tab by the film of the FFC.

[0015] The second connection part is formed of a flexible printed circuit (FPC), and the fuse assembly may further include a plate that mechanically connects both sides of the FPC to the first tab and the second tab.

[0016] The first tab and the second tab are spaced apart from each other and each has a tab through-hole, and the FPC may have a corresponding through-hole corresponding to the tab through-hole.

[0017] The above plate can be formed from a plastic injection molded product.

[0018] The above plate is provided with a coupling projection corresponding to the corresponding through hole and the tap through hole, and after being coupled to the corresponding through hole and the tap through hole, it can be fixed by a hot stacking method.

[0019] The above fuse is provided with a first terminal and a second terminal at both ends, and when the coupling projection is coupled to the corresponding through hole and the tab through hole, the first terminal and the second terminal can be electrically connected to the first tab and the second tab.

[0020] The first connection part is formed of a flexible flat cable (FFC), the second connection part is formed of a flexible printed circuit (FPC), the first tap is connected to the bus bar, the second tap is connected to the FFC, the first tap and the second tap are connected to the FPC, and the fuse assembly may further include a reinforcing member that mechanically reinforces the electrical connection between the first tap and the second tap by the FPC.

[0021] The first connection part is formed of a flexible flat cable (FFC), and the fuse may have a width formed by repeating the sequence of the second direction, the positive first direction, the second direction, and the negative first direction with respect to the first direction in which the strip of the FFC extends and the second direction intersecting the first direction.

[0022] The above fuse has a first terminal and a second terminal provided at both ends formed as a rectangle having a width wider than the width, and can be connected to the first tab and the second tab.

[0023] The above second tab can be formed as a nickel tab.

[0024] A secondary battery pack according to one embodiment of the present invention further comprises a bottom film covering a plurality of battery cells, and a top film disposed on the bus bar, the first connecting part, and the fuse assembly and attached to the bottom film by hot pressing, wherein the bus bar is disposed on the bottom film and can be connected to the battery cells through an opening formed in the bottom film.

[0025] The top film may have an opening corresponding to the opening of the bottom film.

[0026] In one embodiment, a secondary battery pack eliminates the intermediate step of forming modules with battery cells, thereby forming the pack directly with the battery cells. At this time, a busbar and a first connector (e.g., an FFC) are connected to a fuse assembly, and the first and second taps of the fuse assembly are connected to the busbar and the FFC (flexible flat cable), respectively, and the first and second taps are connected to the fuse of the fuse assembly, so that a cell contact system for detecting voltage according to the charge state of the battery cells can be implemented at a low cost. The FFC is connected to a Battery Management System (BMS).

[0027] FIG. 1 is a partially exploded perspective view of a secondary battery pack according to one embodiment of the present invention.

[0028] FIG. 2 is an exploded perspective view of the bottom film, bus bar, first connection part (as an example, FFC), fuse assembly and top film of FIG. 1.

[0029] FIG. 3 is a partial perspective view in which a busbar and an FFC placed on the bottom film of FIG. 1 are connected to a fuse assembly.

[0030] Figure 4 is a plan view of Figure 3.

[0031] Figure 5 is an exploded perspective view of the fuse assembly of Figures 3 and 4.

[0032] FIG. 6 is a plan view of the connection state between a fuse assembly and a first connection part (e.g., FFC).

[0033] Figure 7 is a cross-sectional view taken along the line Ⅶ-Ⅶ of Figure 6.

[0034] Figure 8 is a cross-sectional view taken along line VIII-VIII of Figure 6.

[0035] Hereinafter, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts unrelated to the explanation have been omitted to clearly explain the present invention, and the same reference numerals have been used throughout the specification for identical or similar components.

[0036] FIG. 1 is a partially exploded perspective view of a secondary battery pack according to one embodiment of the present invention, and FIG. 2 is an exploded perspective view of the bottom film, bus bar, first connection part (as an example, FFC), fuse assembly and top film of FIG. 1. Referring to FIG. 1 and FIG. 2, a secondary battery pack of one embodiment includes a plurality of battery cells (10) formed as secondary batteries, a bus bar (30), a first connection part, and a fuse assembly (50). As an example, the first connection part may be formed of an FFC (flexible flat cable) (40) or a PCB (printed circuit board) (not shown).

[0037] Additionally, a secondary battery pack of one embodiment may further include a bottom film (20) and a top film (60). The bottom film (20) and the top film (60) may be replaced by a molding structure. For convenience, one embodiment is described including the bottom film (20) and the top film (60).

[0038] A secondary battery pack includes a cell contact system that contacts a plurality of battery cells (10). The cell contact system includes a bottom film (20), a bus bar (30), a flexible flat cable (FFC) (40), a fuse assembly (50), and a top film (60).

[0039] The secondary battery pack of one embodiment may have various structures, but a detailed description of this configuration is omitted and described as an example. A plurality of battery cells (10) are formed as prismatic secondary batteries and stacked in a first direction (x-axis direction).

[0040] The wide side of the battery cells (10) faces the first direction (x-axis direction), and the narrow side faces the second direction (y-axis direction) which intersects the first direction (x-axis direction). The battery cells (10) form a row along the first direction (x-axis direction) and arrange another row adjacently in the second direction (y-axis direction) to form two parallel rows overall. That is, the battery cells (10) form a secondary battery pack of two rows.

[0041] The bottom film (20) includes a busbar support (21) for connecting and insulating electrode terminals (not shown) of a plurality of battery cells (10), and a vent (22) for discharging gas discharged from a vent of the battery cells (10) to the outside. The vent (22) is spaced apart from the busbar support (21) in a second direction (y-axis direction).

[0042] The busbar support (21) covers the parts other than the electrode terminals of the battery cells (10) while supporting a busbar (30) that connects the electrode terminals of adjacent unit cells (10) in series or parallel by exposing the electrode terminals of the battery cells (10) in a third direction (z-axis direction) that intersects the second direction (y-axis direction).

[0043] A busbar (30) is placed on a bottom film (20) and electrically connects battery cells (10) through an opening (211) formed in the bottom film (20). An opening (211) is formed in the busbar support (21) to expose the electrode terminals of the battery cells (10).

[0044] A flexible flat cable (FFC) (40) is placed on a bottom film (20). The FFC (40) is attached to a busbar (30) and is configured to detect the voltage flowing according to the charge state of the battery cells (10) in the busbar (30), which electrically connects the electrode terminals of the battery cells (10), and to send the detection signal to a battery management system (BMS).

[0045] The fuse assembly (50) has both sides of the fuse (54) electrically connected to the busbar (30) and the FFC (40), respectively, so as to send a voltage signal detected by the busbar (30) to the FFC (40). The fuse assembly (50) will be described in detail below.

[0046] The top film (60) is placed on the busbar (30), FFC (40), and fuse assembly (50) and attached to the bottom film (20) by hot press. The top film (60) has an opening corresponding to the opening of the bottom film (20). That is, the opening of the top film (60) partially opens each part of the busbars (30) and the vent part (22). The busbar cover part (61) corresponding to the busbar support part (21) opens each part of the busbars (30) to enable heat dissipation of the busbars (30), and the vent part (62) prevents the operation of the bottom film (20) vent part (22) from being obstructed.

[0047] FIG. 3 is a partial perspective view in which a busbar and an FFC are connected to a fuse assembly placed on the bottom film of FIG. 1, FIG. 4 is a plan view of FIG. 3, and FIG. 5 is an exploded perspective view of the fuse assembly of FIG. 3 and FIG. 5. Referring to FIG. 3 to FIG. 5, the fuse assembly (50) includes a first tab (51), a second tab (52), and a second connecting part. As an example, the second connecting part may be formed of an FPC (flexible printed circuit) (53) or a PCB (printed circuit board) (not shown).

[0048] The first tap (51) and the second tap (52) are spaced apart from each other in the second direction (y-axis direction) and are connected to the bus bar (30) and the FFC (40), respectively. The FPC (53) electrically connects the first tap (51) and the second tap (52) to each other and is equipped with a fuse (54). Thus, the bus bar (30) and the FFC (40) are electrically connected to each other through the fuse (54).

[0049] The first tap (51) is connected to the busbar (30) by welding. That is, the first tap (51) and the busbar (30) are electrically and mechanically connected. Below, the electrical and mechanical connection between the second tap (52) and the FFC (40) will be described.

[0050] FIG. 6 is a plan view of the connection state between a fuse assembly and a first connection part (e.g., FFC), and FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6. Referring to FIG. 4 through 7, the first connection part, FFC (40), is extended in a first direction (x-axis direction) and has a gap (G) in a second direction (y-axis direction) that intersects the first direction (x-axis direction), and includes a first strip (S1) to an n-th strip (Sn) that forms a circuit for transmitting a detected signal.

[0051] In one embodiment, the FFC (40) includes a first strip (S1) to a twelfth strip (S12). For convenience, in FIGS. 1, 2, 3, 4 and 6, a film (41, 42, see FIGS. 7 and 8) covering the first strip (S1) to the twelfth strip (S12) is not shown.

[0052] The second tab (52) has a width (W) formed in the first direction (x-axis direction), a length (L) formed in the second direction (y-axis direction) corresponding to the FFC (40), and an area (W*L) set by the width (W) and length (L). The area (W*L) allows the second tab (52) to be stably supported because it is positioned over the entire first strip (S1) to the twelfth strip (S12) and comes into contact with a large area.

[0053] The second tab (52) is provided with first through holes (H1) to nth through holes (Hn) corresponding to each of the first strip (S1) to nth strip (Sn). One of the strips from the first strip (S1) to the nth strip (Sn) is exposed and electrically connected by solder to one of the corresponding first through holes (H1) to nth through holes (Hn).

[0054] The area (W*L) based on width (W) and length (L), and the first through holes (H1) to the nth through holes (Hn) enable the second tab (52) to be shared. That is, the second tab (52) can be connected to any one of the first strip (S1) to the twelfth strip (S12).

[0055] The first through holes (H1) are spaced apart along the elongation direction (x-axis direction) of the corresponding first strip (S1). The second through holes (H2) are spaced apart along the elongation direction (x-axis direction) of the corresponding second strip (S2). Additionally, the third through holes (H3) to the twelfth through holes (H12) are likewise spaced apart along the elongation direction (x-axis direction) of the corresponding third strip (S3) to the twelfth strip (S12).

[0056] That is, each of the first through holes (H1) to the nth through holes (Hn) is spaced apart along the elongation direction (x-axis direction) of the corresponding strip. For example, the first through holes (H1) can supply solder (SD1) to the first strip (S1) exposed corresponding to the first through holes (H1). That is, the first through holes (H1) are spaced apart from each other within the width (W) of the second tab (52).

[0057] The second tab (52) is surface-mounted with solder between the strips exposed through the through holes corresponding to the through holes. The second tab (52) is surface-mounted with solder (SD2) between the first strips (S1) exposed corresponding to the first through holes (H1). As an example, the second tab (52) may be formed as a nickel tab. The nickel tab enables smooth welding with the first strip (S1) to the nth strip (Sn) formed of copper.

[0058] To this end, the upper film (41) of the films (41, 42) of the FFC (40) is partially opened to expose the upper surface of the first strip (S1). A plurality of first through holes (H1) enable the rapid and uniform supply of solder (SD1, SD2) over the entire exposed area of ​​the first strip (S1). Thus, surface mounting with a uniform thickness of solder (SD2) is made possible early.

[0059] Among the first strip (S1) to the nth strip (Sn), the strips (S2 to Sn) that are not connected by solder (SD2) are electrically insulated from the second tab (52) by the film (41, 42) of the FFC (40) (see FIG. 8). FIG. 8 illustrates the state in which the fourth strip (S4) to the ninth strip (S9) and the second tab (52) are insulated by the film (41, 42).

[0060] Referring again to FIG. 5, the fuse assembly (50) may further include a plate (55). The plate (55) mechanically connects both sides of the second direction (y-axis direction) of the FPC (53) to the first tab (51) and the second tab (52).

[0061] The first tap (51) and the second tap (52) are spaced apart from each other and each has a tap through hole (511, 521). The second connecting part, the FPC (53), has corresponding through holes (531, 532) corresponding to the tap through holes (511, 521). Since the tap through hole (511) of the first tap (51) is formed as two and the tap through hole (521) of the second tap (52) is formed as two, the corresponding through holes (531, 532) of the FPC (53) are formed as four.

[0062] For example, the plate (55) may be formed from a plastic injection molded product. The plate (55) is provided with a coupling projection (551, 552) corresponding to the corresponding through hole (531, 532) and the tap through hole (511, 521), and after being coupled to the corresponding through hole (531, 532) and the tap through hole (511, 521), it is fixed by a hot stacking method.

[0063] The plate (55) acts as a reinforcing member that mechanically reinforces the electrical connection between the first tab (51) and the second tab (52) by the FPC (53). That is, the plate (55) protects the FPC (53) and the fuse (54), which are the mechanically weakest parts of the fuse assembly (50). Thus, the plate (55) prevents the fuse (54) from being broken by mechanical tension, even though it may be broken by overcurrent.

[0064] The fuse (54) of the FPC (53) is provided with a first terminal (541) and a second terminal (542) at both ends. When the coupling protrusions (551, 552) are coupled to the corresponding through holes (531, 532) and the tap through holes (511, 521), the first terminal (541) and the second terminal (542) are electrically connected to the first tap (51) and the second tap (52).

[0065] Referring again to FIG. 6, the fuse (54) has a width (W1) formed by repeating the sequence of the first direction (x-axis direction) and the second direction (y-axis direction) in which the strip of FFC (50) is extended, the second direction (y-axis direction), the first direction (x-axis direction) of positive (+), the second direction (y-axis direction), and the first direction (x-axis direction) of negative (-).

[0066] The fuse (54) is formed with a first terminal (541) and a second terminal (542) provided at both ends, and is connected to the first tap (51) and the second tap (52) by having a width (W2) wider than the width (W1). The narrow width (W1) sets the operating overcurrent value at which the fuse (54) blows. The first and second terminals (541, 542) with a wide width (W2) secure the electrical connection of the first and second taps (51, 52).

[0067] By using a fuse assembly (50) equipped with such a fuse (54) and a flexible flat cable (FFC), a busbar (30) and a battery management system (BMS) are connected, thereby enabling a cell contact system for detecting the charge status of battery cells (10) to be implemented at a low cost.

[0068] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and can be implemented with various modifications within the scope of the claims, the description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention.

[0069] [Explanation of the symbol]

[0070] 10: Battery cell 20: Bottom film

[0071] 21: Busbar support 22, 62: Vent

[0072] 30: Busbar 40: FFC (flexible flat cable)

[0073] 41, 42: Film 50: Fuse assembly

[0074] 51, 52: 1st and 2nd tabs 53: FPC (flexible printed circuit)

[0075] 54: Fuse 55: Plate

[0076] 60: Top film 61: Busbar cover

[0077] 211: Opening 511, 521: Tap through hole

[0078] 531, 532: Corresponding through holes 541, 542: First and second terminals

[0079] 551, 552: Connecting protrusions H1~Hn: 1st~nth through holes

[0080] L: Length S1~Sn: 1st~nth strip

[0081] S1~S12: 1st~12th strips SD1, SD2: Solder

[0082] W: Width W1, W2: Width

Claims

1. A busbar that electrically connects multiple battery cells; A first connecting part disposed adjacent to the above busbar; and A fuse assembly in which both sides of the fuse are respectively connected to the busbar side and the first connection part side to send a signal detected by the busbar to the first connection part. Includes, The above fuse assembly A first tab and a second tab spaced apart from each other and respectively connected to the busbar and the first connecting part, and A second connecting part that electrically connects the first tap and the second tap via the fuse. A secondary battery pack including 2. In Paragraph 1, The above first tab is A secondary battery pack connected to the above busbar by welding.

3. In Paragraph 1, The above first connecting part is formed of an FFC (flexible flat cable), and The above FFC is A secondary battery pack comprising a first strip to an n-th strip that extends in a first direction and has a gap in a second direction intersecting the first direction, and forms a circuit that transmits a detected signal.

4. In Paragraph 3, The above second tab is The width formed in the first direction above, A length formed in the above second direction corresponding to the FFC, and A secondary battery pack having an area set with the above width and above length.

5. In Paragraph 4, The above second tab is A secondary battery pack having first through holes to n through holes corresponding to each of the first strip to n strip.

6. In Paragraph 5, One of the first to nth strips above is, A secondary battery pack electrically connected to the second tab by solder supplied to one of the exposed and corresponding first through holes to the nth through holes.

7. In Paragraph 6, Each of the above first through holes to the above nth through holes is, A secondary battery pack that supplies solder at multiple points of the corresponding strip that are spaced apart along the elongation direction of the corresponding strip and are correspondingly exposed.

8. In Paragraph 7, The above second tab is A secondary battery pack surface-mounted with solder between the strips exposed in correspondence with the above.

9. In Paragraph 6, The strips among the first to nth strips that are not connected by solder are A secondary battery pack electrically insulated from the second tab by the film of the above FFC.

10. In Paragraph 1, The above second connection part is formed of an FPC (flexible printed circuit), and The above fuse assembly A secondary battery pack further comprising a plate that mechanically connects both sides of the above FPC to the first tab and the second tab.

11. In Paragraph 10, The above first tab and the above second tab are They are spaced apart from each other and each is equipped with a tap through hole, The above FPC is A secondary battery pack having a corresponding through hole corresponding to the above-mentioned tab through hole.

12. In Paragraph 11, The above plate is A secondary battery pack formed from plastic injection molding.

13. In Paragraph 12, The above plate is A secondary battery pack having a coupling projection corresponding to the corresponding through hole and the tab through hole, which is coupled to the corresponding through hole and the tab through hole and then fixed by a hot stacking method.

14. In Paragraph 13, The above fuse is equipped with a first terminal and a second terminal at both ends, and When the above coupling projection is coupled to the corresponding through hole and the tab through hole, A secondary battery pack in which the first terminal and the second terminal are electrically connected to the first tab and the second tab.

15. In Paragraph 1, The above first connecting part is formed of an FFC (flexible flat cable), and The above second connection part is formed of an FPC (flexible printed circuit), and The first tab above is connected to the busbar, and The above second tap is connected to the above FFC, and The first tab and the second tab are connected to the FPC, and The above fuse assembly A secondary battery pack further comprising a reinforcing member that mechanically reinforces the electrical connection between the first tab and the second tab by the above FPC.

16. In Paragraph 1, The above first connecting part is formed of an FFC (flexible flat cable), and The above fuse is With respect to the first direction in which the FFC strip extends and the second direction intersecting the first direction, A secondary battery pack having a width formed by repeating the order of the above second direction, the positive first direction, the above second direction, and the negative first direction.

17. In Paragraph 16, The above fuse is The first terminal and the second terminal provided at both ends are formed as a rectangle having a width wider than the width, A secondary battery pack connected to the first tab and the second tab above.

18. In Paragraph 1, The above second tab is formed as a nickel tab, in a secondary battery pack.

19. In Paragraph 1, A bottom film covering the plurality of battery cells, and It further includes a top film disposed on the busbar, the first connecting part, and the fuse assembly and attached to the bottom film by hot pressing, and The above busbar is A secondary battery pack disposed on the bottom film and connected to the battery cells through an opening formed in the bottom film.

20. In Paragraph 19, The above top film is A secondary battery pack having an opening corresponding to the opening of the bottom film.

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