JP2012199045A - Battery pack and separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a battery pack in which temperature unevenness of a battery in a passage direction of cooling air can be improved; and a separator.SOLUTION: In a battery pack 10, a plurality of batteries 1 are arranged while sandwiching a separator 7 having insulation properties therebetween, and the batteries 1 are cooled by blowing cooling air between the batteries 1. The separator 7 includes a cooling air passage 24, through which the cooling air passes, between each of the batteries 1 and the separator, and a heat transfer suppression part 23 for suppressing heat exchange between the batteries 1 and the cooling air is provided on an upstream side of the cooling air passage 24.

Description

  The present invention relates to an assembled battery in which a plurality of batteries are arranged, and a separator interposed between the batteries constituting the assembled battery.

  Conventionally, a battery device including an assembled battery in which a plurality of batteries are arranged is known. In this type of battery device, when configuring an assembled battery, for example, a resin separator made of an insulator is disposed between the batteries. In this type of separator, a cooling air passage for allowing cooling air to pass is formed, and cooling air is blown to the cooling air passage with a blower or the like between the cooling air passing through the cooling air passage and the battery. The battery is cooled by heat exchange (see, for example, Patent Document 1).

JP 2004-362879 A

  By the way, in recent years, the battery device has been miniaturized, and the gap between the batteries of the assembled battery tends to be narrowed. Thereby, the flow path width of the cooling air passage formed in the separator interposed in the narrow gap between the batteries is narrowed. In recent years, the size of a blower for blowing cooling air has been reduced, and the power consumption of the blower and noise reduction have been promoted. The flow rate is slow. Therefore, while passing through the cooling air passage, the temperature of the cooling air rises due to heat exchange with the battery, and a temperature difference may occur between the upstream side and the downstream side of the cooling air, and the battery may be uneven in temperature.

  This invention is made | formed in view of the situation mentioned above, and aims at providing the assembled battery which can improve the temperature unevenness of the battery in the flow path direction of a cooling wind, and a separator.

  In order to achieve the above object, the present invention is configured by arranging a plurality of batteries with an insulating separator interposed therebetween, and cooling the batteries by blowing cooling air between these batteries. In the assembled battery, the separator includes a cooling air passage through which the cooling air passes between the battery and the heat transfer suppression that suppresses heat exchange between the battery and the cooling air upstream of the cooling air passage. A feature is provided.

  In this configuration, the heat transfer suppression unit may cover the battery surface to prevent contact between the battery surface and the cooling air. Further, the heat transfer suppression unit may cover the battery surface in a range smaller than 1/6 from the upstream side of the cooling air passage toward the flow direction of the cooling air. The separator has a recess and a protrusion extending in a depth direction of the battery, and a space formed between the battery and the battery corresponding to the recess and the protrusion is used as the cooling air passage. The heat transfer suppression unit may be provided so as to cover the void. Moreover, the said heat-transfer suppression part is good also as a structure which is formed in the substantially rectangular cylinder shape and arrange | positioned the opening part in parallel with respect to the said cooling air path.

  In order to achieve the above object, the present invention is a separator that is interposed between a plurality of batteries constituting an assembled battery and insulates between the batteries, and cooling air passes between the batteries. A cooling air passage is provided, and a heat transfer suppression unit that suppresses heat exchange between the battery and the cooling air is provided upstream of the cooling air passage.

  According to the present invention, a plurality of batteries are arranged with an insulative separator interposed therebetween, and an assembled battery in which cooling air is blown between the batteries to cool the batteries. Is provided with a cooling air passage through which the cooling air passes between the battery and a heat transfer suppression unit that suppresses heat exchange between the battery and the cooling air upstream of the cooling air passage. The temperature rise on the upstream side of the cooling air passage of the wind can be suppressed, and the cooling air having a low temperature can be blown downstream. As a result, a sufficient temperature difference between the cooling air and the battery on the downstream side of the cooling air passage can be secured, and the cooling efficiency of the battery on the downstream side can be promoted. There is an effect that uneven temperature can be improved.

It is an external appearance perspective view which shows the assembled battery which concerns on one embodiment of this invention. It is a perspective view which shows a separator. It is a perspective view which shows the structure of a separator. It is a figure which shows the relationship between the length of a heat-transfer suppression part, and battery temperature. It is a perspective view which shows the separator of another embodiment. It is a perspective view which shows the separator of another embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The assembled battery 10 according to the present embodiment is an in-vehicle assembled battery mounted on a hybrid vehicle or an electric vehicle that uses an electric motor as a drive source, and is not illustrated. Located between the seat and the trunk room. As described above, the in-vehicle assembled battery 10 has a limited installation space for the assembled battery 10 and is arranged using a narrow space, so that downsizing progresses and a gap between the batteries tends to be narrowed.

  FIG. 1 is a perspective view of an assembled battery 10 according to an embodiment to which the present invention is applied.

  The assembled battery 10 is configured by stacking a plurality of batteries (cells) 1 back and forth on a heat insulating plate 2. The battery 1 is a thin prismatic battery that is thinner than the width thereof, and the positive electrode and the negative electrode that are output terminals 4 are projected apart from the top surface of the rectangular corner case 3 that is chamfered. The protruding position of the output terminal 4 is a position where the positive electrode and the negative electrode are symmetrical. Thereby, when the batteries 1 are alternately turned over and overlapped, the positive electrode and the negative electrode overlap each other, and the plurality of batteries 1 can be easily connected in series. As the battery 1, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a nickel cadmium battery can be used. In particular, a lithium ion battery has a high output per unit volume and is suitable for downsizing and high output, and thus can be suitably used. In addition, not only a secondary battery but a primary battery can also be utilized.

  The output terminal 4 has positive and negative output terminals 4 bent in a cross-sectional L shape in opposite directions. When the batteries 1 are alternately turned over and stacked, the positive and negative output terminals 4 are alternately reversed in the adjacent batteries 1 and the positive electrode and the negative electrode are stacked. Moreover, these output terminals 4 are formed in a size and shape that can be connected between adjacent batteries 1. Further, a connecting hole is opened in the bent portion of the output terminal 4, and the bent portions stacked on each other can be connected by inserting a connecting bolt into the connecting hole. Thereby, between the adjacent batteries 1, the positive electrode and negative electrode of the output terminal 4 are directly connected, and a plurality of batteries are connected in series. The output terminal 4 may be configured to connect adjacent batteries 1 in series with each other using a metal plate bus bar.

  Although illustration is omitted, the end of the assembled battery 10 is connected to a control circuit, and the control circuit measures the voltage, current, temperature, etc. of each battery 1, and determines the battery capacity, the required charge / discharge amount, etc. Control such as charging and discharging is performed. By connecting a plurality of batteries 1 in series, the output can be increased without increasing the output voltage, but the assembled battery 10 can also be configured by connecting the batteries 1 in parallel. Moreover, the assembled battery 10 may be configured to include an end plate at an end thereof.

  In addition, although not shown in the figure, the battery 1 is inserted into a rectangular case 3 that is an outer can formed in a bottomed cylindrical shape, and a wound electrode is inserted from the opening and injected with an electrolytic solution. Is sealed and formed by laser welding or the like. The square case 3 is made of a metal having excellent thermal conductivity. The sealing plate is provided with a safety valve, and is configured such that when the battery is charged / discharged in an abnormal state, the safety valve is opened and the electrolyte is discharged. The battery 1 also includes terminal ribs that stand upright so as to surround the output terminal 4. Thereby, even if the electrolyte injected into the rectangular case 3 leaks from the periphery of the output terminal 4, a situation where the electrolyte is inadvertently diffused is prevented.

  Between each battery 1, as shown in FIG. 2, the separator 7 which has insulation is arrange | positioned. The separator 7 is configured such that each battery 1 can be cooled by air cooling with an appropriate space between the batteries 1 and cooling air flowing in the space. Although not shown, a supply duct for supplying the air from the blower to the interval formed by each separator 7 is connected to one side surface 10A side of the assembled battery 10, and the other side surface 10B of the assembled battery 10. Connected to the side is an exhaust duct for exhausting the cooling air flowing through the interval formed by each separator 7 to the outside. Thereby, the assembled battery 10 can be cooled by air cooling.

  The separator 7 is a resin molded product manufactured by, for example, resin molding. When the assembled battery 10 is configured by combining the battery 1 and the separator 7, the battery 1 is held so as to surround all corners of the battery 1. Holding part 21 and insulating part 22 interposed between batteries 1 adjacent to each other. According to this configuration, all the corners of the battery 1 which is a thin prismatic battery can be covered with the separator 7, and the insulation of the battery 1 can be maintained even when the battery 1 receives an impact from the outside. Can do.

  The insulating portion 22 includes a heat transfer suppressing portion 23 and a cooling air passage portion (cooling air passage) 24. The heat transfer suppression unit 23 is provided on the upstream side of the cooling air passage unit 24. When the assembled battery 10 is configured by combining the battery 1 and the separator 7, the heat transfer suppression unit 23 includes an abutting portion 23 </ b> A that abuts against the mutually opposing surfaces of the adjacent batteries 1. A cooling air supply unit 23B that supplies cooling air to the cooling air passage unit 24 is formed inside the contact portion 23A.

  The cooling air passage section 24 is provided on the downstream side of the cooling air supply section 23B, and is configured by repeating a rectangular wave-shaped concave 24A, convex 24B, concave 24A, convex 24B. These concave portions 24A, convex portions 24B, concave portions 24A, convex portions 24B,... Extend in parallel to the depth direction of the battery 1, and correspond to these concave portions 24A, convex portions 24B, concave portions 24A, convex portions 24B,. .. Are formed between the path portion 24 and the battery 1 in parallel with each other. Each of the voids 25, 25... Penetrates from the one side surface 10A side to the other side surface 10B side of the assembled battery shown in FIG.

  When the assembled battery 10 is configured by combining the battery 1 and the separator 7, a part of the surface of the battery 1 is covered with the contact portion 23 </ b> A of the heat transfer suppression unit 23. Thus, the cooling air flowing through the cooling air supply unit 23B is supplied to the cooling air passage unit 24 without directly touching the surface of the battery 1. Thus, the temperature of the cooling air supplied to the cooling air passage unit 24 while suppressing the heat exchange between the cooling air flowing through the cooling air supply unit 23B formed inside the heat transfer suppression unit 23 and the battery 1. The rise can be suppressed.

  According to this configuration, it is possible to suppress the temperature increase on the one side surface 10A side of the cooling air flowing from the one side surface 10A side to the other side surface 10B side and to reduce the temperature of the cooling air on the other side surface 10B side. it can. Thereby, cooling of the battery 1 on the other side surface 10B side can be promoted, and the difference in surface temperature between the one side surface 10A side and the other side surface 10B side of the battery 1 can be reduced. Therefore, temperature unevenness in the flow direction of the cooling air of the battery 1 can be improved.

  As shown in FIG. 3A, the contact portion 23A of the heat transfer suppression portion 23 includes one surface 23C and the other surface 23D. One surface 23 </ b> C is provided integrally with the insulating portion 22, and the other surface 23 </ b> D is configured by a plate-like member 23 </ b> E formed separately from the insulating portion 22. A plurality of ribs 26 are provided on one surface 23 </ b> C so as to stand inside the insulating portion 22. The plate-like member 23E constituting the other surface 23D is bonded to the insulating portion 22 with the rib 26 interposed therebetween. As a result, as shown in FIG. 3B, a cooling air supply unit 23B composed of a plurality of rooms separated by ribs 26 is formed between one surface 23C and the other surface 23D. .

  The ribs 26 are provided at positions corresponding to the recesses 24A, protrusions 24B, recesses 24A, protrusions 24B,. Thereby, the cooling air flowing between the adjacent ribs 26 of the cooling air supply unit 23B is configured to be blown to the spaces 25, 25. That is, the heat transfer suppression unit 23 is provided so as to cover the void 25 formed between the separator 7 and the battery 1, and prevents contact between the cooling air flowing in the void 25 and the battery 1, and the cooling air and the battery It is comprised so that the heat exchange between 1 may be suppressed.

FIG. 4 is a diagram illustrating the relationship between the ratio of the length of the heat transfer suppression unit 23 to the depth of the separator 7 and the battery temperature. The inventors measured the temperature at a plurality of points on the surface of the battery 1 by variously changing the ratio of the length of the heat transfer suppressing portion 23 to the depth of the separator 7. The flow path width of the cooling air, that is, the equivalent diameter of the space 25 formed between the cooling air passage portion 24 and the battery 1 is 3 mm , and the average flow velocity of the cooling air is 1.5 to 4.1 m / s. . The cooling air flow is a laminar flow where the Reynolds number is 1500 or less.

FIG. 4A is a diagram in which the horizontal axis represents the ratio of the length of the heat transfer suppression unit 23 to the depth of the separator 7, and the vertical axis represents the temperature difference of the battery 1. Line a is the length of the heat transfer suppression unit 23 when the ratio of the average temperature of the battery 1 when the ratio of the length of the heat transfer suppression unit 23 to the depth of the separator 7 is 50% is used as a reference. Shows the temperature unevenness of the battery 1 with respect to the ratio of the length to the depth of the separator 7 . Line b indicates the length of the heat transfer suppression unit 23 when the length of the heat transfer suppression unit 23 is 50% of the depth of the separator 7 and the increase in the average temperature of the battery 1 is used as a reference. Shows the average temperature of the battery 1 with respect to the ratio of the length to the depth of the separator 7 . As shown in FIG. 4A, when the ratio of the length of the heat transfer suppression unit 23 to the depth length of the separator 7 increases, the temperature unevenness of the battery 1 is improved, but the average temperature of the battery 1 increases. .

FIG. 4B is a diagram illustrating the relationship between the ratio of the length of the heat transfer suppression unit 23 to the depth of the separator 7 and the temperature efficiency of the battery 1. As shown in FIG. 4B, when the ratio of the length of the heat transfer suppressing portion 23 to the depth of the separator 7 increases, the temperature efficiency of the battery 1 decreases. In order to avoid a significant decrease in the temperature efficiency of the battery 1 (a decrease of 30% or more), the ratio of the length of the heat transfer suppression portion 23 to the depth length of the separator 7 is 1 of the entire depth length of the separator 7. It was obtained from the experimental results that it is preferable to set it to about / 6 (17%) or less.

That is, even when the flow path is narrow and the flow velocity of the cooling air is slow, the heat transfer suppressing portion 23 formed in the separator 7 to have a length of about 1/6 (17%) or less of the entire depth of the separator 7. By providing, it is possible to suppress a decrease in battery temperature and an increase in temperature of the cooling air on the upstream side of the cooling air, and to improve temperature unevenness in the flow direction of the cooling air of the battery 1. It became clear by experiment.

  Next, another embodiment will be described.

  In the above-described embodiment, the contact portion 23A of the heat transfer suppressing portion 23 is formed integrally with the insulating portion 22, and is formed into the concave 24A, convex 24B, concave 24A, convex 24B,. One surface 23 </ b> C having a rib 26 provided at a corresponding position and the other surface 23 </ b> C configured by a plate-like member 23 </ b> E bonded to the insulating portion 22 with the rib 26 interposed therebetween. According to this configuration, since the plurality of ribs 26 are formed between the one surface 23C and the other surface 23C, the strength of the heat transfer suppressing portion 23 can be increased. It is considered that the cost for molding increases.

  In this embodiment, since the separator 70 is formed integrally with the holding portion 21 and the cooling air passage portion 24, and the heat transfer suppressing portion 73 is formed separately from the holding portion 21, the separator 70 The molding cost of 70 can be suppressed. In this embodiment, the same reference numerals are given in the drawings for the same configurations as those in the above embodiment, and the description thereof is omitted.

  As shown in FIGS. 5 and 6, the separator 70 includes a heat transfer suppression unit 73, a holding unit 21, and a cooling air passage unit 24. As shown in FIG. 6, the cooling air passage portion 24 is formed integrally with the holding portion 21. When the assembled battery 10 is configured by combining the battery 1 and the separator 70, the cooling air passage portion 24 is provided close to the other side surface 10 </ b> B side of the assembled battery. As shown in FIG. 5, a heat transfer suppressing portion 73 formed separately from the holding portion 21 is fitted to one side surface 10 </ b> A side of the assembled battery. The heat transfer suppression part 73 is formed in a substantially rectangular cylindrical shape, and the opening 74 is provided between the cooling air passage part 24 and the battery 1 and is parallel to the cavities 25, 25. Has been placed.

  The heat transfer suppression unit 73 has a thickness T1 that is substantially the same as the thickness T2 of the cooling air passage unit 24. In addition, the width W1 of the opening 74 of the heat transfer suppressing portion 73 is formed to be substantially the same as the width W2 of the space 25 provided between the cooling air passage portion 24 and the battery 1. Thereby, when the assembled battery 10 is configured by combining the battery 1 and the separator 70, a part of the surface of the battery 1 is covered with the heat transfer suppressing unit 73. Therefore, the cooling air guided from the opening 74 to the inside of the heat transfer suppressing unit 73 is supplied to the cooling air path unit 24 without directly touching the surface of the battery 1. The ratio of the length of the heat transfer suppression unit 73 to the depth of the separator 70 is about 1/6 (17%) or less of the entire depth of the separator 70 from the temperature unevenness of the battery 1 and the cooling efficiency. It is preferable to do this.

  As described above, according to the embodiment to which the present invention is applied, a plurality of batteries 1 are arranged with the separators 7 and 70 having insulation therebetween, and between these batteries 1 is cooled. In the assembled battery 10 that blows wind to cool the battery 1, the separators 7 and 70 include a cooling air passage 24 through which the cooling air passes between the battery 1 and the battery upstream of the cooling air passage 24. 1 and the heat transfer suppression part 23 and 73 which suppress heat exchange with cooling air were provided. As a result, even when the flow path of the cooling air between the batteries 1 is narrow and the flow velocity of the cooling air is slow, the decrease in the temperature of the battery 1 on the upstream side of the cooling air and the increase in the temperature of the cooling air are suppressed. Can do. Therefore, a temperature difference between the upstream side and the downstream side of the cooling air is less likely to occur, and the temperature unevenness of the battery 1 in the cooling air flow direction can be improved.

Further, according to this embodiment of the present invention, the heat transfer suppressing portion 23, 73 covers the surface of the battery 1, since that prevents contact with the surface of the battery 1 and the cooling air, the heat transfer suppressing portion 23, 73 The heat exchange between the surface of the battery 1 covered with the cooling air and the cooling air is suppressed, and the temperature decrease and cooling of the battery 1 on the upstream side of the cooling air covered by the heat transfer suppressing portions 23 and 73 are reduced. Wind temperature rise can be suppressed. Therefore, a temperature difference between the upstream side and the downstream side of the cooling air is less likely to occur, and the temperature unevenness of the battery 1 in the cooling air flow direction can be improved.

Further, according to the embodiment to which the present invention is applied, the heat transfer suppression units 23 and 73 make the surface of the battery 1 smaller than 1/6 from the upstream side of the cooling air passage 24 toward the flow direction of the cooling air. Since it covers the range, it is possible to prevent a significant increase in the average temperature of the battery 1 and a significant decrease in the temperature efficiency of the battery 1, and to improve the temperature unevenness in the flow direction of the cooling air of the battery 1. .

Further, according to the embodiment to which the present invention is applied, the separator 7 has the recesses 24A, the protrusions 24B, the recesses 24A, the protrusions 24B... Extending in the depth direction of the battery 1, and these recesses 24A, protrusions The space 25 formed between the battery 1 corresponding to the 24B, the concave 24A, the convex 24B,... Is used as the cooling air passage 24, and the heat transfer suppressing portion 23 is provided so as to cover the space. It was. Accordingly, heat exchange between the cooling air flowing through the void 25 and the battery 1 can be suppressed by the heat transfer suppression unit 23. Therefore, with a simple structure, a decrease in battery temperature on the upstream side of the cooling air and an increase in temperature of the cooling air can be suppressed, and temperature unevenness in the flow direction of the cooling air of the battery 1 can be improved. it can.

Further, according to the embodiment to which the present invention is applied, the heat transfer suppressing portion 73 is formed in a substantially rectangular tube shape, and the opening portion 74 is arranged in parallel to the cooling air passage 24, and thus is formed in a substantially rectangular tube shape. By supplying the cooling air flowing inside the heat transfer suppressing unit 73 to the cooling air passage 24, heat exchange between the cooling air flowing inside the heat transfer suppressing unit 73 and the battery 1 can be suppressed. Thereby, with a simple structure, it is possible to suppress a decrease in battery temperature on the upstream side of the cooling air and an increase in temperature of the cooling air, and improve temperature unevenness in the flow direction of the cooling air of the battery 1. Can do .

DESCRIPTION OF SYMBOLS 1 Battery 7, 70 Separator 10 Assembly battery 21 Holding part 23, 73 Heat-transfer suppression part 24 Cooling air path (cooling air path part)
24A concave 24B convex 25 void

Claims (6)

In the assembled battery in which a plurality of batteries are arranged with an insulating separator in between, and the batteries are cooled by blowing cooling air between these batteries.
The separator includes a cooling air passage through which the cooling air passes between the battery and a heat transfer suppression unit that suppresses heat exchange between the battery and the cooling air on an upstream side of the cooling air passage. A battery pack characterized by that.   The assembled battery according to claim 1, wherein the heat transfer suppression unit covers the battery surface and prevents contact between the battery surface and the cooling air.   The said heat-transfer suppression part covers the said battery surface in the range smaller than 1/6 toward the distribution direction of the said cooling wind from the upstream of the said cooling wind path, The Claim 1 or 2 characterized by the above-mentioned. Battery pack.   The separator has a recess and a protrusion extending in the depth direction of the battery, and a space formed between the battery and the recess corresponding to the protrusion and the protrusion serves as the cooling air passage. The assembled battery according to any one of claims 2 to 3, wherein a heat transfer suppressing portion is provided so as to cover the void.   The assembled battery according to any one of claims 2 to 3, wherein the heat transfer suppression portion is formed in a substantially rectangular cylindrical shape, and an opening portion is arranged in parallel to the cooling air passage. A separator that is interposed between a plurality of batteries constituting an assembled battery and insulates between the batteries,
A cooling air passage through which cooling air passes is provided between the battery, and a heat transfer suppression unit that suppresses heat exchange between the battery and the cooling air is provided upstream of the cooling air passage. separator.