JP2013229266A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool down a plurality of batteries 2, and to enhance a degree of freedom in layout.SOLUTION: A battery module 1 comprises: a plurality of laminated flat batteries 2; end plates 3 and 4 arranged above and below the batteries 2; bus bar modules 5 and 6 respectively arranged at both end parts of the batteries 2; a pair of heat transfer plates 7 overlapped outside the bus bar modules 5 and 6 via heat transfer sheets 11; a battery controller 8; and cases 9 and 10 at both end parts. Electrode tabs 21 at both ends of the batteries 2 are bonded to bus bars 31 via slits of the bus bar modules 5 and 6. The heat transfer plate 7 is configured so that a heat collection part 45 and a heat radiation part 46 are continuous in a substantially L shape. Heat of each battery 2 is propagated to the heat collection part 45 from the electrode tab 21 by heat conduction, and dissipated to an other cooling frame and the like from the heat radiation part 46 at a lower surface.

Description

  The present invention relates to an assembled battery formed by stacking a plurality of flat batteries, and more particularly to a cooling structure for the battery.

  In lithium ion secondary batteries and the like used as power sources for electric vehicles and hybrid vehicles in recent years, the temperature rise of the battery accompanying a chemical reaction is relatively remarkable. Some kind of cooling means is required.

  Patent Document 1 discloses an assembled battery in which a plurality of flat batteries each having a pair of electrode terminals arranged on one side edge are arranged in an upright posture such that the electrode terminals are arranged on the upper surface. Yes. Here, a large number of electrode terminals are connected to each other by a cap-shaped bus bar provided with cooling fins, and a cover-shaped insulating member is provided so as to cover between the bus bars arranged in a plurality of rows. These bus bars and insulating members form a flow path through which cooling air flows between each battery case, and this cooling air flows along the surface of each electrode terminal. Cooling is planned.

JP 2009-277378 A

  In the conventional configuration as described above, since the flow path is configured to guide the cooling air directly to the electrode terminals, the degree of freedom in layout is small, and a plurality of assembled batteries are accommodated in the battery pack. In some cases, the orientation of each battery and the arrangement of the assembled battery are limited. In addition, the metal cap-shaped bus bar and the electrode terminal serve as a substantial heat radiating portion. However, when the thickness of each battery is thin (or when the number of stacked layers is small), a sufficient heat radiating area may be secured. Can not.

  The present invention is an assembled battery in which a plurality of flat batteries with electrode tabs led out from the end portions are stacked and the electrode tabs are joined to bus bars of a bus bar module provided along the end portions. The heat collecting part and the heat radiating part are provided with a heat transfer plate which is substantially L-shaped. The said heat collection part is connected to the said electrode tab or bus bar, and the said heat radiating part is extended along surfaces other than the said edge part of this assembled battery.

  In a preferred embodiment, electrode tabs are led out from both end portions of the battery, and the bus bar module is provided at each end portion. The pair of bus bar modules and both sides of a plurality of stacked batteries are provided. The assembled battery is formed in a rectangular parallelepiped shape by fixing a pair of end plates positioned at each other. And the said thermal radiation part is extended along the surface of the said end plate.

  That is, in the present invention, heat is transferred from the electrode tab of each battery (or each bus bar to which the electrode tab is joined) to the heat collecting portion of the heat transfer plate in the form of heat conduction, Heat is radiated from the heat radiating portion extending along the surface.

  In addition, since the said heat-transfer plate is generally comprised from the metal which has electroconductivity, in one example, the heat-transfer sheet which has insulation is interposed between the said bus-bar and the said heat collection part. This heat transfer sheet is made of a known synthetic resin type or rubber type sheet material excellent in heat conductivity and electrical insulation, and avoids short circuit between a plurality of bus bars and at the same time from the electrode tab to the heat transfer plate. Ensures heat conduction.

  In general, the temperature of a plurality of batteries is non-uniform, for example, the one near the center of the plurality of stacked batteries tends to be hot and the one near both sides tends to be relatively low, Although there is an individual difference in heat generation, in the above configuration, the plurality of electrode tabs are thermally connected to a common cooling plate (heat collecting part), so that the temperature difference between the batteries is reduced. And since the thermal radiation part of a heat-transfer plate can be arrange | positioned on arbitrary surfaces other than the bus-bar module of an assembled battery, a thermal radiation area can be ensured enough large and the freedom degree of layout becomes high. For example, even when the number of battery stacks is small or when the thickness of each battery is small, a large heat dissipation area can be easily ensured by disposing the heat dissipation part in parallel with the main surface of the flat battery.

  The heat radiation from the heat radiation part may be, for example, natural heat radiation by the surrounding air, cooling by forced cooling air flow, or arranged so that the heat radiation part is in contact with another cooling plate. The heat radiation part may be cooled by the cooling plate.

  In one aspect, the heat radiating portion is in contact with the cooling plate on a cooling plate that is housed in a battery pack mounted under the floor of the vehicle and includes a refrigerant passage disposed on the bottom surface of the battery pack. Be placed.

  According to the present invention, the degree of freedom in layout such as the posture of each battery and the arrangement of the assembled battery in the battery pack is increased, and it is easy to secure a large heat radiation area. Therefore, effective cooling of each battery can be achieved. Moreover, the temperature of a some battery can be made more uniform through the cooling plate which connects a some battery thermally.

The perspective view of the battery module which is one Example of the assembled battery which concerns on this invention. The exploded perspective view of this battery module. The perspective view of the bottom face side of this battery module. The perspective view which shows only the some battery laminated | stacked and arrange | positioned. The side view which shows only a battery similarly. The perspective view of a front bus-bar module. The perspective view of a rear bus-bar module. The perspective view of the state which assembled the bus-bar module and the end plate. The side view of the state which attached the heat-transfer plate to the bus-bar module outer side. The expanded sectional view of the A section. The perspective view of the state which similarly attached the heat-transfer plate to the bus-bar module outer side. The perspective view in the single body of a cooling plate. The perspective view which shows the attachment state of the battery controller with respect to a bus-bar module. The perspective view which shows one Example which has arrange | positioned the battery module further on the cooling plate. The perspective view which shows the cooling plate of this Example. The perspective view which shows the other Example which has arrange | positioned the battery module further on the cooling plate. The perspective view which shows the cooling plate of this Example. The perspective view which shows the further another Example which has arrange | positioned the battery module on the cooling plate. The perspective view which shows the example of arrangement | positioning in the case of comprising a some bus bar module as a battery pack. The perspective view which shows the example of the battery module which has arrange | positioned the thermal radiation part of the heat-transfer plate on the side surface. The perspective view which shows the example of arrangement | positioning in the case of comprising a some battery module as a battery pack using this battery module.

  FIG. 1 shows an embodiment of an assembled battery, that is, a battery module 1 according to the present invention. FIG. 2 is an exploded perspective view of the battery module 1.

  First, the components of the battery module 1 will be briefly described with reference to FIG. 2. The battery module 1 includes a plurality of, for example, ten flat batteries 2 stacked on each other, and a bottom surface of the stacked batteries 2. A lower end plate 3 and an upper end plate 4 that are further stacked on the side and the upper surface side, and a front bus bar module 5 and a rear bus bar module 6 that are respectively disposed at both ends of the stacked battery 2, The pair of end plates 3, 4 and the pair of bus bar modules 5, 6 constitute a basic housing that surrounds the battery 2. Further, the battery module 1 is disposed outside the bus bar modules 5 and 6, on the outside of the heat transfer plate 7 on the front bus bar module 5 side. And a front case 9 and a rear case 10 which are attached so as to cover the bus bar modules 5, 6 and the heat transfer plate 7 at both ends.

  The battery 2 is a rectangular laminate-type battery in which one or a plurality of rectangular positive electrodes, negative electrodes, and separators are laminated and a laminate film is used as an exterior, as shown in FIGS. Electrode tabs 21 each made of a thin metal plate are led out in the form of a band from the center of both end portions serving as sides. One of the pair of electrode tabs 21 is a positive electrode and the other is a negative electrode, but these are basically configured in the same shape, and the ten batteries 2 include a positive electrode tab 21 and a negative electrode tab. The layers are stacked in alternate directions so that 21 are alternately arranged. As can be easily understood from FIG. 5, the ten positive electrodes 2 and the negative electrode tabs 21 are connected to each other so that the ten batteries 2 are connected in series as a whole.

  4 and 5, the electrode tab 21 is shown in a bent state, but this shows a state after being assembled to the bus bar modules 5 and 6, as will be described later. The tab 21 has a planar shape extending in parallel with the main surface of the flat battery 2.

  Although the said battery 2 consists of a lithium ion secondary battery, for example, this invention is not limited to this, A battery of various types can be utilized.

  FIG. 6 shows details of the front bus bar module 5, and FIG. 7 shows details of the rear bus bar module 6. These bus bar modules 5 and 6 basically have a similar configuration, and metal such as copper or brass to which the electrode tabs 21 arranged as shown in FIG. 5 are joined by welding, soldering, or the like, respectively. A bus bar 31 made of metal is fixedly supported by a synthetic resin substrate 30 having a rectangular shape (substantially square). For example, in one example, the bus bar 31 is integrally molded when the substrate 30 is molded. However, the bus bar 31 may be attached by some means after the substrate 30 is molded. Each bus bar 31 is exposed on the outer surface of the substrate 30, that is, the surface opposite to the position of the battery 2, and has a number of linear shapes corresponding to the number of combinations of the positive and negative electrode tabs 21 shown in FIG. Bus bars 31 are arranged in parallel to each other.

  Specifically, in the rear bus bar module 6 shown in FIG. 7, there are five bus bars 31, and slits 32 through which the electrode tabs 21 can pass are formed along the upper and lower edges thereof. In addition, the front bus bar module 5 shown in FIG. 6 includes four bus bars 31 for connecting the positive and negative electrode tabs 21 to each other, as well as the uppermost electrode tab 21 shown in FIG. There are an upper bus bar 31 (particularly indicated by reference numeral 31A) and a lowermost bus bar (particularly indicated by reference numeral 31B) for connection to the lowermost electrode tab 21 shown in FIG. 31 exists. The front bus bar module 5 includes a pair of module terminals 33 fixed to the upper edge of the front bus bar module 5 with stud bolts or the like. 33 is conducted. As can be easily understood from FIG. 5, the uppermost bus bar 31A has a slit 32 along its lower edge, and the lowermost bus bar 31B has a slit 32 along its upper edge. Note that the bus bars 31 other than these bus bars 31A and 31B simply connect the adjacent electrode tab 21 on the positive electrode side and the electrode tab 21 on the negative electrode side, and thus are independent of each other.

  The lower end plate 3 and the upper end plate 4 are rectangular plate-shaped members made of a hard synthetic resin or a metal material (iron, aluminum, stainless steel, etc.). As shown in FIG. The bus bar modules 5 and 6 are fixed to both ends of the longitudinal direction 4 by screws 35. Thereby, the housing | casing 42 which makes | forms the rectangular parallelepiped shape where the two surfaces 41 and 41 of both sides were open | released is comprised, and the 10 laminated | stacked batteries 2 are accommodated in the inner side. The casing 42 protects the laminated battery 2.

  Here, when the bus bar modules 5 and 6 are assembled to the end plates 3 and 4 as described above, the electrode tabs 21 of the respective batteries 2 are inserted into the slits 32 of the bus bar modules 5 and 6. Then, as shown in FIG. 8, FIG. 4, etc., the tip end portion of the electrode tab 21 penetrating the slit 32 is bent along the surface of the bus bar 31 (31A, 31B), and is welded or soldered. 31A and 31B) are respectively joined to the surface.

  The heat transfer plate 7 is disposed outside the casing 42 configured as described above, and as shown in FIG. 12, the heat collecting portion 45 and the heat radiating portion 46 are continuously formed in an approximately L shape. The shape is made. That is, the heat transfer plate 7 is made of a metal material having a high thermal conductivity such as aluminum, copper, iron, or the like, and is configured by bending a rectangular metal plate into a substantially L shape. The heat collecting portion 45 has a rectangular shape large enough to cover the plurality of bus bars 31 to which the electrode tabs 21 are joined, and is shown in FIGS. 9 and 11 through small holes 48 provided at the four corners. As shown, the screws 47 are attached to the bus bar modules 5 and 6. Here, since the heat transfer plate 7 is generally formed of a conductive metal, as shown in an enlarged view in FIG. 10 in order to prevent a short circuit between the bus bars 31 and absorb fine irregularities on the contact surface. The flexible heat transfer sheet 11 is interposed between the heat transfer plate 7 and the bus bar 31. The heat transfer sheet 11 is made of a known synthetic resin or rubber sheet material having excellent heat conductivity and electrical insulation, and is attached in advance to the inner surface of the heat collecting portion 45 of the heat transfer plate 7, for example. Yes. Therefore, the heat of the electrode tab 21 is transmitted to the heat collecting part 45 in the form of heat conduction not through the air layer.

  On the other hand, the heat dissipating part 46 bent by approximately 90 ° with respect to the heat collecting part 45 is the remaining four surfaces of the casing 42 having a rectangular parallelepiped shape (that is, the upper surface, the lower surface and the left and right open sides of the casing 42 adjacent to the bus bar modules 5 and 6 Extending along one of the surfaces 41). In the illustrated example, as shown in FIGS. 9 and 3, it extends along the lower surface of the casing 42, that is, the surface of the lower end plate 3. Specifically, a rectangular concave portion 49 corresponding to the heat radiating portion 46 is formed on the lower surface of the lower end plate 3, and the heat radiating portion 46 is fitted in the concave portion 49. The outer surface, that is, the lower surface of the heat radiating portion 46 is substantially flush with the surface of the lower end plate 3 around the recess 49.

  The heat transfer plate 7 on the front bus bar module 5 side and the heat transfer plate 7 on the rear bus bar module 6 side have basically the same configuration and are arranged symmetrically with each other as can be understood from FIG. The two heat radiating portions 46 occupy most of the area of the lower surface of the lower end plate 3.

  The front case 9 and the rear case 10 are made of, for example, a synthetic resin molded product, and cover the outer sides of the bus bar modules 5 and 6 so that the bus bars 31 and the like of the bus bar modules 5 and 6 are not exposed to the outside. . The front case 9 and the rear case 10 are attached to the bus bar modules 5 and 6 simply by being fitted around them. However, the front case 9 and the rear case 10 may be securely fixed with screws or the like. Here, the battery controller 8 is accommodated in the front case 9 as described above.

  As shown in FIG. 13, the battery controller 8 is provided with circuit components and connectors 52 (not shown) on the circuit board 51 for charge / discharge control of the battery 2, and screws at the four corners of the circuit board 51. 53 is fixed to the front bus bar module 5. An appropriate gap is secured between the circuit board 51 and the front bus bar module 5, and the heat collecting portion 45 of the heat transfer plate 7 is located in this gap.

  In the battery module 1 configured as described above, heat generated inside the battery 2 due to charging / discharging of the battery 2 is transmitted from the electrode tab 21 to the heat collecting unit 45. This heat is further transferred from the heat collecting portion 45 to the heat radiating portion 46 and is radiated to the outside in the heat radiating portion 46. In other words, each battery 2 is cooled by cooling the heat radiating part 46 with outside air or the like, and the temperature rise of the battery 2 is suppressed.

  Here, in the above configuration, since the electrode tabs 21 of the plurality of batteries 2 are thermally connected to the single heat collecting part 45, when there is a temperature difference between the batteries 2, the temperature difference Is relaxed, and the temperature of each battery 2 becomes more uniform. Therefore, even when there are individual differences in the heat generation of the batteries 2, early deterioration of some of the batteries 2 can be avoided.

  Further, the heat radiation area of the heat radiating portion 46 is not limited to the dimensions of the bus bar modules 5 and 6 and can be sufficiently widened. And since the heat radiation part 46 can be arrange | positioned in arbitrary positions, the freedom degree of layout becomes high, for example, in the battery pack which accommodated the several battery module 1, arrange | position the heat radiation part 46 so that cooling is easy. Can do. Moreover, since the heat radiating portion 46 is provided at a position away from the electrode tab 21 and the bus bar 31, the electrode tab 21 and the bus bar 31 can be covered with the cases 9 and 10 without impairing the heat radiating performance. This is advantageous in preventing short circuits and the like.

  The heat radiation from the heat radiation part 46 can be performed in various ways. FIG. 14 and FIG. 15 show an embodiment thereof. In this example, the battery module 1 having the heat radiating portion 46 in the lower end plate 3 is fixed on another cooling plate 61 as described above. ing. The cooling plate 61 is made of an aluminum alloy or the like and includes therein an air passage 62 through which cooling air flows as a refrigerant. A rectangular window portion 63 is formed in a region corresponding to the heat radiating portion 46 of the battery module 1. An opening is formed. That is, the cooling air supplied by a blower (not shown) passes through the air passage 62, and at that time, the cooling air directly contacts the heat radiating portion 46 exposed to the air passage 62 in the window portion 63. To do. Thereby, the heat radiating portion 46 is effectively cooled.

  16 and 17 show different embodiments of the cooling plate 65 on which the battery module 1 is mounted. In this embodiment, the cooling plate 65 includes therein a cooling water passage 66 through which cooling water flows as a refrigerant, and the heat radiating portion 46 of the battery module 1 contacts the upper surface thereof. In this embodiment, the cooling water at an appropriate temperature is circulated through the cooling water passage 66, whereby the cooling of the heat radiating portion 46 and the cooling of the battery 2 are performed.

  FIG. 18 shows an embodiment of a cooling plate 68 that does not have a refrigerant passage, and a plurality of cooling fins 69 are formed on the lower surface of the cooling plate 68. Therefore, in this embodiment, the heat radiating portion 46 is cooled by the heat radiation to the outside air via the cooling fins 69. In this embodiment, more effective cooling is possible if the lower surface of the cooling plate 68 is arranged so as to receive the traveling wind of the vehicle, for example.

  14 to 18 show only one battery module 1, it is needless to say that a plurality of battery modules 1 can be arranged on a common cooling plate 61, 65, 68.

  FIG. 19 shows a configuration example when a plurality of battery modules 1 are arranged on a cooling plate 71 as a battery pack mounted under the vehicle floor of an electric vehicle. In this example, four battery modules 1 are arranged adjacent to each other in one row, and three rows are provided with a slight gap. That is, it is an array of 4 × 3 battery modules 1. The module terminals 33 of each battery module 1 are connected to each other by a bus bar 72 so as to constitute an appropriate electrical connection. Further, the battery controllers 8 of the battery modules 1 are connected to each other by a communication line 73.

  In the illustrated example, the cooling plate 71 has a plurality of refrigerant passages 75 inside, and is forcibly cooled by flowing cooling air or cooling water. As a result, as described above, the heat dissipating part 46 and thus each battery 2 is cooled. The final battery pack includes a pack case (not shown), and a plurality of battery modules 1 are accommodated in the pack case together with the cooling plate 71.

  In the case of a battery pack mounted under the floor of a vehicle, since vehicle traveling wind flows on the lower surface of the battery pack, the bottom of the battery pack is relatively cooler than the upper portion. Therefore, as shown in FIG. 19, each battery 2 can be more effectively cooled by disposing the cooling plate 71 at the bottom of the battery pack together with the heat radiating portion 46 of each battery module 1.

  20 and 21 show another configuration example in the case where a plurality of battery modules 1 are arranged as a battery pack. As shown in FIG. 20, the battery module 1 used in this example has a configuration in which a heat radiating portion 46 is provided on an open side surface 41 of a casing 42 having a rectangular parallelepiped shape. That is, the heat transfer plate 7 extends from the heat collecting portion 45 overlapping the bus bar modules 5 and 6 to the side of the housing 42 and covers the open surface 41 on the side of the battery 2.

  The battery module 1 having such a configuration is arranged in a 4 × 3 shape in the battery pack as in the above-described embodiment. In this embodiment, instead of the above-described cooling plate 71, A cooling frame 81 is used for cooling each heat radiating portion 46. The cooling frame 81 includes an entrance side beam 82, an exit side beam 83, and a pair of cooling beams 84 extending in a direction perpendicular to the entrance side beam 82. Each beam 82, 83, 84 is vertically Has a rectangular cross-sectional shape larger than the dimension in the thickness direction, and specifically has a height dimension substantially corresponding to the height of the battery module 1. Inside these beams 82, 83, 84, a refrigerant passage 85 is formed continuously from the inlet side beam 82 to the outlet side beam 83 via the cooling beam 84, and cooling air or cooling water flows therethrough. It is forcibly cooled by.

  Each battery module 1 is disposed on each side of each cooling beam 84 such that the heat radiation portion 46 on the side surface is in contact with the side surface of the cooling beam 84. In other words, in the pair of battery modules 1 disposed on both sides of the cooling beam 84, the positions of the heat radiating portions 46 are symmetrical, and the heat radiating portions 46 are in contact with both surfaces of the cooling beam 84. doing.

  Similarly to the embodiment described above, the module terminals 33 are connected to each other by a bus bar 72, and the battery controller 8 is connected to each other by a communication line 73.

  In FIG. 21, the portions 82a and 83a of the entrance side beam 82 and the exit side beam 83 that protrude to the upper left side in the figure may be omitted.

  Thus, the battery module 1 of the present invention can change the arrangement of the heat radiating portion 46 in accordance with the arrangement of the cooling plate 71, the cooling frame 81, etc., and has a high degree of freedom in layout.

  As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, A various change is possible.

  For example, in the battery module 1 of the above embodiment, a plurality of batteries 2 are connected in series. However, the present invention can also be applied to a battery module in which a plurality of batteries 2 are connected in parallel.

  Further, in the heat transfer plate 7 of the above embodiment, the heat collecting portion 45 and the heat radiating portion 46 are formed of one plate-like member, but the heat collecting portion 45 and the heat radiating portion 46 are made of separate plate-like members. They may be configured to be connected by screws or the like, and furthermore, the heat collecting part 45 and the heat radiating part 46 that are separately arranged may be thermally connected by a heat pipe.

  Further, the heat radiating portion 46 of the heat transfer plate 7 may be wider than the heat collecting portion 45 so as to ensure a larger heat radiating area. If the heat collecting portion 45 is excessively wide, the heat capacity of each portion of the heat collecting portion 45 becomes large, which is not necessarily preferable for the uniform temperature of the plurality of batteries 2 described above. In other words, it is desirable to have the minimum necessary dimension that substantially corresponds to the width (in other words, the width of the electrode tab 21). In addition, as the said heat-transfer plate 7, the heat radiating part 46 can also be provided in the both sides of the heat collecting part 45, respectively, that is, you may comprise the heat-transfer plate 7 so that a whole may become a substantially U shape.

DESCRIPTION OF SYMBOLS 1 ... Battery module 2 ... Battery 3 ... Lower end plate 4 ... Upper end plate 5 ... Front bus bar module 6 ... Rear bus bar module 7 ... Heat transfer plate 8 ... Battery controller 9 ... Front case 10 ... Rear case 11 ... Heat transfer sheet 21 ... Electrode tab 31 ... Bus bar 45 ... Heat collecting part 46 ... Heat dissipation part

Claims (4)

A plurality of flat batteries in which electrode tabs are led out from the end portions are arranged in a stack, and the battery tabs are joined to the bus bars of the bus bar module provided along the end portions.
The heat collecting part and the heat radiating part are provided with a heat transfer plate which is continuous in a substantially L shape,
The assembled battery, wherein the heat collecting part is connected to the electrode tab or bus bar, and the heat radiating part extends along a surface other than the end part of the assembled battery. The electrode tabs are led out from both ends of the battery, and the bus bar module is provided at each end,
The assembled battery is configured in a rectangular parallelepiped shape by fixing the pair of bus bar modules and the pair of end plates located on both sides of the plurality of stacked batteries,
The assembled battery according to claim 1, wherein the heat radiating portion extends along a surface of the end plate.   The assembled battery according to claim 1 or 2, wherein an insulating heat transfer sheet is interposed between the bus bar and the heat collecting part.   The heat dissipating part is disposed so as to be in contact with the cooling plate on a cooling plate that is housed in a battery pack mounted under a vehicle floor and includes a refrigerant passage disposed on a bottom surface of the battery pack. The assembled battery according to any one of claims 1 to 3.

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