Battery pack

Abstract

To provide a battery pack capable of preventing moisture above a busbar from flowing downward through the gaps formed between adjacent bus bars and reaching the terminals of the battery cells.SOLUTION: The battery pack has a battery case for accommodating a battery stack, multiple busbars and cover material. The battery pack includes: a battery stack 15 having multiple battery cells 17 stacked in a predetermined direction, multiple busbars 40, 45 connecting the terminals on the top of two adjacent battery cells, which are located above the upper surface and each having conductivity; cover materials 22 L, 22R accommodating multiple busbars, which includes a gap closing portion 31 that fills the gap between adjacent busbars, and each has insulation.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Patent Document 1 listed below discloses a battery unit including a battery stack having a plurality of battery cells stacked in a predetermined direction, and a plurality of conductive bus bars located above the battery cells and connecting terminals provided on the upper surfaces of two adjacent battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-054940 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery unit of Patent Document 1, for example, moisture contained in condensation that occurs above the bus bars may pass downward through the gaps formed between adjacent bus bars and adhere to the battery cells located directly below the bus bars, which may cause a short circuit between the terminals of the adjacent battery cells.

[0005] In consideration of the above, an object of the present invention is to provide a battery pack that can prevent moisture above a bus bar from passing downward through gaps formed between adjacent bus bars and flowing toward the terminals of a battery cell. [Means for solving the problem]

[0006] A battery pack of a first aspect includes a battery stack having a plurality of battery cells stacked in a predetermined direction; a plurality of bus bars that connect terminals provided on upper surfaces of two adjacent battery cells and are located above the upper surfaces and are each conductive; a cover member that houses the plurality of bus bars and has gap closing portions that fill gaps between adjacent bus bars and has insulating properties; and a battery case that houses the battery stack, the bus bars, and the cover member. Equipped with.

[0007] A first aspect of the battery pack includes a battery stack having a plurality of battery cells stacked in a predetermined direction, a plurality of conductive bus bars located above the upper surfaces of the battery cells and connecting terminals provided on the upper surfaces of two adjacent battery cells, and an insulating cover member that houses the plurality of bus bars. The cover member further includes a gap closing portion that fills the gap between adjacent bus bars. Therefore, the gap closing portion can prevent moisture above the bus bars from passing downward through the gap formed between the adjacent bus bars and flowing toward the terminals of the battery cells.

[0008] A second aspect of the battery pack is the same as the first aspect, except that the cover member includes a plurality of busbar storage sections that respectively store a plurality of the busbars, at least one gap closure section formed between adjacent busbar storage sections, and a cooling member storage section that is located directly above the busbar storage section and the gap closure section and stores a cooling member that contacts the busbars.

[0009] In the battery pack of the second aspect, the bus bars are cooled by a cooling member stored in a cooling member storage section of the cover member. Furthermore, when condensation occurs around the cooling member, the condensed water may flow down into the bus bar storage section and the gap closing section. However, because the cover member includes a gap closing section that fills the gap between adjacent bus bars, the gap closing section can prevent the condensed water from passing downward through the gap between the adjacent bus bars and flowing toward the terminals of the battery cells.

[0010] A third aspect of the battery pack is the first or second aspect, wherein the cover member has an annular outer wall that positions the bus bar on its inner side in a plan view, and the bus bar has a protrusion that penetrates a portion of the annular outer wall in a liquid-tight manner and is conductive.

[0011] In the battery pack of the third aspect, the bus bar has a conductive protrusion that penetrates a portion of the annular outer wall of the cover member in a liquid-tight manner. Therefore, for example, this protrusion can be used to electrically connect two battery stacks. Furthermore, because the protrusion penetrates a portion of the annular outer wall in a liquid-tight manner, moisture adhering to the bus bar does not flow along the protrusion to the outside of the annular outer wall and further to the battery cells.

[0012] A fourth aspect of the battery pack is any one of the first to third aspects, wherein the cover member has a bottom wall that faces the bus bar from below, and the bus bar has a terminal connection portion that penetrates a portion of the bottom wall in a liquid-tight manner and is electrically connected to the terminal.

[0013] In the battery pack of the fourth aspect, the bus bar has a terminal connection portion that penetrates a portion of the bottom wall of the cover member in a liquid-tight manner and electrically connects to the terminal. Therefore, electrical continuity is established between the bus bar and the terminal via the terminal connection portion. Furthermore, because the terminal connection portion penetrates a portion of the bottom wall in a liquid-tight manner, there is no risk of moisture adhering to the bus bar flowing along the terminal connection portion to the terminal side of the battery cell.

[0014] A battery pack of a fifth aspect is the battery pack of the third or fourth aspect, wherein the cover member is made of resin and is provided integrally with the plurality of bus bars.

[0015] According to the battery pack of the fifth aspect, the cover member can be manufactured, for example by insert molding, so that no gaps through which moisture can pass are formed between the annular outer wall and the protrusion, or between the bottom wall and the terminal connection portion. [Effects of the Invention]

[0016] As described above, the battery pack according to the present invention has the excellent effect of being able to prevent moisture above the bus bars from passing downward through the gaps formed between adjacent bus bars and flowing toward the terminals of the battery cells. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a battery pack according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing a battery module, which is a component of the battery pack, with sensors and harnesses omitted. [Figure 3] FIG. 2 is a schematic plan view showing the battery module with the cooling member omitted. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along the arrow line 4-4 in FIG. [Figure 5] FIG. 5 is a schematic cross-sectional view taken along the arrow line 5-5 in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along the arrow line 6-6 in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0018] A battery pack 10 according to an embodiment will be described below with reference to the accompanying drawings. Note that in each drawing, the arrows UP, FR, and LH indicate the upper side in the vehicle vertical direction, the front side in the vehicle longitudinal direction, and the left side in the vehicle width direction, respectively.

[0019] The battery pack 10 of this embodiment is mounted on a vehicle. The electric power generated by the battery pack 10 is supplied to, for example, an electric motor that is a drive device of the vehicle.

[0020] As shown in FIGS. 1 and 2, the battery pack 10 includes a plurality of battery modules 12 and a battery case 60.

[0021] The battery module 12 includes a battery stack 15, cover modules 20L and 20R, a cooling member 50, and a sensor 55.

[0022] The battery stack 15 includes a plurality of battery cells 17 arranged in the front-rear direction, and a plurality of insulating partition members 16 (see FIG. 3) provided between adjacent battery cells 17. Each battery cell 17 includes a cell body 18 having a substantially rectangular parallelepiped shape, and a pair of terminals 19 extending upward from the top surface of the cell body 18. The battery cells 17 and the partition members 16 are fixed to each other by a restraining member (not shown) with one terminal of each cell body 18 aligned in the front-rear direction and the other terminal of each cell body 18 aligned in the front-rear direction.

[0023] The left cover module 20L includes a resin cover member 22L and a first bus bar (bus bar) 40 made of a conductive material such as metal. On the other hand, the right cover module 20R includes a resin cover member 22R, the first bus bar 40, and a second bus bar (bus bar) 45 made of a conductive material such as metal.

[0024] The cover member 22L includes a flat bottom wall 23 having a rectangular planar shape that is elongated in the front-to-rear direction, and an annular outer peripheral wall 24 extending upward from the outer peripheral edge of the bottom wall 23. Furthermore, eight recessed first busbar storage sections (busbar storage sections) 25 are formed on the upper surface of the bottom wall 23 and aligned in the front-to-rear direction. Furthermore, seven gap closure sections 31 are formed between adjacent first busbar storage sections 25 on the bottom wall 23. Each first busbar storage section 25 has a rectangular planar shape. Furthermore, a bottom through-hole 27 (see FIG. 4 ) is formed on the lower surface of the bottom wall 23, connecting each first busbar storage section 25 to a space below the lower surface of the bottom wall 23. Furthermore, a side through-hole 29 is formed in the right side wall 24R of the annular outer peripheral wall 24, connecting each first busbar storage section 25 to a space to the right of the right side wall 24R. Furthermore, the space above the cover member 22L is formed by one cooling member storage section 33 that is located directly above the bottom surface (upper surface) of the bottom wall 23 and has a rectangular planar shape that is long in the front-rear direction.

[0025] A first bus bar 40 is housed in each first bus bar housing portion 25 of the cover member 22L. Each first bus bar 40 includes a base portion 41 having substantially the same shape as the first bus bar housing portion 25, a terminal connection portion 42 (see FIG. 4 ) extending downward from the center of the lower surface of the base portion 41, and a protrusion 43 extending to the right from the side surface of the base portion 41. As shown in FIG. 4 , the base portion 41 of each first bus bar 40 is fitted into the first bus bar housing portion 25, and the upper surface of the base 41 and the upper surface of the bottom wall 23 are substantially flush with each other. Furthermore, the lower end of the terminal connection portion 42 of each first bus bar 40 is located below the bottom wall 23 via a bottom through-hole 27. Furthermore, as shown in FIG. 5 , the protrusion 43 of each first bus bar 40 penetrates the corresponding side through-hole 29 to the right.

[0026] Cover member 22L is molded integrally with each of the first bus bars 40 by insert molding, which is performed with the eight first bus bars 40 placed inside a molding die (not shown). As a result, a liquid-tight state is formed between the terminal connection portion 42 of each first bus bar 40 and the bottom through-hole 27, and a liquid-tight state is also formed between the protruding piece 43 of each first bus bar 40 and the side through-hole 29.

[0027] Furthermore, a cooling member 50 having substantially the same shape as the cooling member storage section 33 is stored in the cooling member storage section 33 of the cover member 22L, and the lower surface of the cooling member 50 contacts the upper surface of each base section 41.

[0028] The cover member 22R has a structure similar to that of the cover member 22L. Specifically, the cover member 22R includes a flat bottom wall 23 having a rectangular planar shape that is long in the front-rear direction, and an annular outer peripheral wall 24 that extends upward from the outer peripheral edge of the bottom wall 23. Two second busbar storage sections (busbar storage sections) 26 and seven first busbar storage sections 25 located between the two second busbar storage sections 26 are formed on the upper surface of the bottom wall 23 of the cover member 22R and are aligned in the front-rear direction. Furthermore, eight gap closure sections 31 are formed between adjacent first busbar storage sections 25 on the bottom wall 23 and between adjacent first busbar storage sections 25 and second busbar storage sections 26. The front-rear dimension of each second busbar storage section 26 is shorter than the front-rear dimension of the first busbar storage section 25. Furthermore, nine bottom through-holes 27 (see FIG. 6 ) are formed in the lower surface of the bottom wall 23, connecting each of the first busbar storage sections 25 and the two second busbar storage sections 26 to a space below the lower surface of the bottom wall 23. Furthermore, seven side through-holes 29 are formed in the left wall 24L of the annular outer peripheral wall 24, connecting each of the first busbar storage sections 25 to a space to the left of the left wall 24L, and one side through-hole 29 is formed, connecting the front second busbar storage section 26 to a space to the left of the left wall 24L. Furthermore, as shown in FIG. 6 , side through-holes 30 are formed in two locations, one at the front and one at the back, of the right wall 24R of the annular outer peripheral wall 24 of the cover member 22R, connecting each second busbar storage section 26 to a space to the right of the right wall 24R. Furthermore, the upper space of the cover member 22R is defined by a single cooling member storage section 33.

[0029] A first bus bar 40 is housed in each first bus bar housing portion 25 of the cover member 22R. The base portion 41 of each first bus bar 40 is fitted into the first bus bar housing portion 25, and the upper surface of the base portion 41 is substantially flush with the upper surface of the bottom wall 23. Furthermore, the lower end portion of the terminal connection portion 42 of each first bus bar 40 is located below the bottom wall 23 via the bottom through-hole 27. Furthermore, the protrusion 43 of each first bus bar 40 passes through the corresponding side through-hole 29 to the left.

[0030] Each second busbar 45 is accommodated in each second busbar storage section 26 of the cover member 22R. Each second busbar 45 includes a base 46 having substantially the same shape as the second busbar storage section 26, a terminal connection section 47 extending downward from the center of the lower surface of the base 46, and a protrusion 48 extending to the right from the side surface of the base 46. Furthermore, a protrusion 43 is provided on the left side surface of the base 46 of the front second busbar 45. As shown in FIG. 6 , the base 46 of each second busbar 45 is fitted into the second busbar storage section 26, and the upper surface of the base 46 and the upper surface of the bottom wall 23 are substantially flush with each other. Furthermore, the lower end of the terminal connection section 47 of each second busbar 45 is positioned below the bottom wall 23 via the bottom through-hole 27. Furthermore, the protrusion 48 of each second busbar 45 penetrates the corresponding side through-hole 30 to the right. 2 and 6, the front shape (cross section) of protrusion 48 is crank-shaped. Furthermore, protrusion 43 of front second bus bar 45 passes through corresponding side through-hole 29 to the left.

[0031] Cover member 22R is molded integrally with each of the first bus bars 40 and each of the second bus bars 45 by insert molding, which is performed with seven first bus bars 40 and two second bus bars 45 arranged inside a molding die (not shown). As a result, a liquid-tight state is formed between the terminal connection portion 42 of each first bus bar 40 and the terminal connection portion 47 of each second bus bar 45 and each of the bottom through-holes 27, a liquid-tight state is formed between the protrusions 43 of each first bus bar 40 and each of the second bus bars 45 and each of the side through-holes 29, and a liquid-tight state is formed between the protrusions 48 of each of the second bus bars 45 and each of the side through-holes 30.

[0032] Furthermore, the cooling member 50 is stored in the cooling member storage portion 33 of the cover member 22R, and the lower surface of the cooling member 50 contacts the upper surfaces of the base portions 41, 46.

[0033] The left cover module 20L, which has a cover member 22L accommodating the cooling member 50, is disposed directly above the left side of each cell body 18, and the terminal connection portions 42 of each first bus bar 40 contact the upper end surfaces of the terminals 19 of the two battery cells 17 located directly below it (see FIGS. 3, 4, and 5). That is, the terminal connection portions 42 contact the positive (+) terminal 19 and the negative (-) terminal 19. Furthermore, in this state, the left cover module 20L is fixed to the battery stack 15 by a fixing means (not shown). Similarly, the right cover module 20R, which has a cover member 22R accommodating the cooling member 50, is disposed directly above the right side of each cell body 18, and the terminal connection portions 42 of each first bus bar 40 contact the upper end surfaces of the terminals 19 of the two battery cells 17 located directly below it. That is, the terminal connection portions 42 contact the positive (+) terminal 19 and the negative (-) terminal 19. Furthermore, the terminal connection portions 47 (see FIG. 6) of the front and rear second bus bars 45 are brought into contact with the upper end surface of the terminal 19 of one battery cell 17 located directly below them. Furthermore, in this state, the right cover module 20R is fixed to the battery stack 15 by fixing means (not shown).

[0034] 3, sensors 55 for detecting the temperatures of each first bus bar 40 and the front second bus bar 45 are connected to the upper surface of each protrusion 43 that protrudes laterally from the side surface of the cover members 22L, 22R of the left and right cover modules 20L, 20R. The ends of harnesses 56 extending from each sensor 55 on the opposite side to the sensor 55 are connected to a control device (not shown) provided outside the battery pack 10.

[0035] As shown in Fig. 1, two battery modules 12 having such a configuration are arranged side by side in the left-right direction. The right battery module 12 shown by the imaginary line in Fig. 1 has a structure that is bilaterally symmetrical to the left battery module 12. The protruding pieces 48 of the corresponding second bus bars 45 of the left and right battery modules 12 are connected to each other via metal conductive members 58 (see Fig. 6).

[0036] Furthermore, as shown in FIG. 1, each battery module 12 is housed inside a battery case 60 .

[0037] (Action and effect) Next, the operation and effects of the embodiment will be described.

[0038] The battery pack 10 of the embodiment configured as described above includes a battery stack 15 having a plurality of battery cells 17 stacked in the front-rear direction, a plurality of conductive first bus bars 40 and second bus bars 45 located above the top surfaces of the cell bodies 18 and connecting terminals 19 provided on the top surfaces of the cell bodies 18 of two adjacent battery cells 17, and insulating cover members 22L and 22R that house the first bus bars 40 and second bus bars 45. Furthermore, the cover members 22L and 22R include a plurality of gap closure portions 31 that fill gaps between adjacent first bus bar housing portions 25 and second bus bar housing portions 26 (first bus bars 40 and second bus bars 45). In the battery pack 10, when condensation occurs around the cooling member 50 due to the function of the cooling member 50, the condensed water may flow downward and adhere to the upper surface of the bottom wall 23 and the upper surfaces of the bases 41 and 46 of the first and second bus bars 40 and 45. However, the bottom walls 23 of the cover members 22L, 22R are provided with a plurality of gap closure portions 31 that fill gaps between adjacent first busbar storage portions 25 and gaps between adjacent first busbar storage portions 25 and second busbar storage portions 26. Therefore, each gap closure portion 31 prevents condensation water adhering to the upper surface of the bottom wall 23 and the upper surfaces of the bases 41 of the first busbars 40 and the bases 46 of the second busbars 45 from passing downward through the gaps between adjacent first busbar storage portions 25 and the gaps between adjacent first busbar storage portions 25 and second busbar storage portions 26 and flowing toward the terminals 19 of the cell body 18. Therefore, each gap closure portion 31 reduces the risk of short-circuiting due to condensation water between two terminals 19 that have different potentials.

[0039] Furthermore, each of the first bus bars 40 and the front second bus bar 45 of the battery pack 10 has a conductive protrusion 43 that penetrates a portion of the annular outer wall 24 of the cover members 22L, 22R. Furthermore, each of the protrusions 43 is provided with a sensor 55. Therefore, the temperature of each of the first bus bars 40 and second bus bars 45 can be detected using each of the protrusions 43. In other words, the temperature of each of the first bus bars 40 and second bus bars 45 can be used to detect the temperature of each of the battery cells 17.

[0040] Furthermore, each second bus bar 45 of the battery pack 10 has a conductive protrusion 48 that penetrates a portion of the annular outer wall 24 of the cover members 22L, 22R. Furthermore, the protrusions 48 of two adjacent battery modules 12 are electrically connected to each other via a conductive member 58.

[0041] Furthermore, the protrusions 43 of each first bus bar 40 pass through the side through-holes 29 formed in the annular outer wall 24 in a liquid-tight manner, and the protrusions 48 of each second bus bar 45 pass through the side through-holes 30 formed in the annular outer wall 24 in a liquid-tight manner. Therefore, there is no risk that moisture adhering to the first bus bar 40 and the second bus bar 45 will flow along the protrusions 43 and 48 to the outside of the annular outer wall 24, and then flow downward along the outer surface of the annular outer wall 24 toward the cell main body 18.

[0042] Furthermore, each first bus bar 40 of the battery pack 10 has a terminal connection portion 42 that penetrates the bottom wall 23 and contacts the terminal 19 of the cell body 18, and each second bus bar 45 has a terminal connection portion 47 that penetrates the bottom wall 23 and contacts the terminal 19 of the cell body 18. Therefore, the first bus bar 40 and the second bus bar 45 can be electrically connected to each terminal 19 via the terminal connection portions 42, 47.

[0043] Furthermore, since the terminal connection portions 42, 47 pass through the bottom through-holes 27 provided in the bottom wall 23 in a liquid-tight state, there is no risk of moisture adhering to the first bus bar 40 and the second bus bar 45 flowing along the terminal connection portions 42, 47 to the terminal 19 side of each battery cell 17.

[0044] Furthermore, the cover modules 20L, 20R of the battery pack 10 are manufactured by insert molding, which allows the cover members 22L, 22R to be manufactured in such a way that no gaps through which moisture can pass are formed between the annular outer wall 24 and the protruding pieces 43, 48, or between the bottom wall 23 and the terminal connecting portions 42, 47.

[0045] Although the battery pack according to the embodiment has been described above, the design thereof can be appropriately modified within the scope of the gist of the present invention.

[0046] For example, the number of battery cells 17 included in one battery stack 15 may be any number equal to or greater than four. Note that if the number of battery cells 17 included in one battery stack 15 is changed, the number of first bus bars 40 will change, and therefore the number of first bus bar housing portions 25 and the number of gap closure portions 31 formed in the cover members 22L and 22R will also change. For example, if there are four battery cells 17, the number of gap closure portions 31 formed in the cover member 22L will be one.

[0047] The sensor 55 may be a voltage sensor that measures the voltage value of the electricity flowing through the first bus bar 40 and the second bus bar 45, or a current sensor that measures the current value of the electricity flowing through the first bus bar 40 and the second bus bar 45.

[0048] The number of battery modules 12 (battery stacks 15) housed in one battery case 60 may be one, or may be three or more. [Explanation of symbols]

[0049] 10 Battery pack 15 Battery stack 17 Battery Cells 19 terminals 22R cover material 23 Bottom wall 24 Circular outer wall 25 First busbar storage section (busbar storage section) 26 Second busbar storage section (busbar storage section) 31 Gap Closure 33 Cooling material storage section 40 First bus bar (bus bar) 42 Terminal connection 43 Projection piece 45 Second bus bar (bus bar) 47 Terminal connection part 48 Projection piece 50 Cooling member 60 Battery Case

Claims

1. a battery stack having a plurality of battery cells stacked in a predetermined direction; a plurality of bus bars each having conductivity and connected to terminals provided on the upper surfaces of two adjacent battery cells, the bus bars being located above the upper surfaces; a cover member that houses the bus bars, includes gap closing portions that fill gaps between adjacent bus bars, and has insulating properties; a battery case that houses the battery stack, the bus bar, and the cover member; A battery pack comprising:

2. The cover member is a plurality of bus bar storage sections for storing the plurality of bus bars, respectively; at least one gap closure portion formed between adjacent bus bar accommodating portions; a cooling member storage portion located directly above the bus bar storage portion and the gap closing portion and configured to store a cooling member in contact with the bus bar; The battery pack according to claim 1 , comprising:

3. the cover member has an annular outer peripheral wall on the inner peripheral side of which the bus bar is positioned in a plan view, 3. The battery pack according to claim 1, wherein the bus bar includes a conductive protrusion that penetrates a portion of the annular outer wall in a liquid-tight manner.

4. the cover member includes a bottom wall facing the bus bar from below, 3. The battery pack according to claim 1, wherein the bus bar has a terminal connection portion that penetrates a part of the bottom wall in a liquid-tight manner and is electrically connected to the terminal.

5. The cover member is made of resin, The battery pack according to claim 3 , wherein the cover member is integrally provided on a plurality of the bus bars.

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