JP6065823B2 - Temperature control structure of power storage device - Google Patents

Description

  The present invention relates to a temperature control structure of a power storage device in which a plurality of power storage elements are stacked.

  The assembled battery can be configured by stacking a plurality of unit cells, for example. At this time, a cooling path for cooling air for cooling each unit cell can be formed between the unit cells adjacent in the stacking direction.

JP 2007-31124 A

  In the assembled battery, if the cross-sectional area of the cooling path is small, the pressure loss of the cooling air is generated, and the cooling performance of the unit cell may be deteriorated. On the other hand, in order to improve the cooling performance of the single cells, if the distance between the single cells is increased to increase the path cross-sectional area of the cooling air, the assembled battery is increased in size.

  In addition, as a method for improving the cooling performance of the unit cell, there is a method of providing a heat dissipation fin on the surface of the unit cell as in Patent Document 1, but the heat dissipation fin is positioned so as to protrude toward the other adjacent unit cell. The interval between the single cells must be increased, and the assembled battery cannot suppress an increase in size.

  An object of the present invention is to provide a temperature control structure of a power storage device that can efficiently control the temperature of the power storage device while suppressing an increase in size of the power storage device.

  The temperature control structure of a power storage device according to the present invention is a temperature control structure of a power storage device in which a plurality of power storage elements are arranged in a predetermined direction, and is arranged between power storage elements adjacent to each other in a predetermined direction to constitute a power storage element There is provided a spacer that forms a flow path through which air for temperature adjustment flows in from the bottom surface side of the battery case and flows out to the end portion in the left-right direction of the electricity storage element viewed from a predetermined direction. The battery case has a step that extends from the top surface to the bottom surface where the electrode terminal of the storage element facing the bottom surface of the battery case is provided at the end corresponding to the outflow side of the flow path, and is recessed inward in a predetermined direction. The step portion is formed so as to be inclined from the upper surface to the bottom surface of the battery case.

  According to the present invention, the stepped portion recessed inward is provided at the end of the battery case corresponding to the outflow side (outlet side) of the flow path formed between adjacent power storage elements. The cross-sectional area near the outlet can be increased in the temperature adjusting air flow path without increasing the interval. For this reason, while being able to suppress the pressure loss of air, since the area which air contacts is expanded by a level | step difference, temperature control performance can be improved.

  Furthermore, the step portion can be configured to be inclined from the upper surface to the bottom surface of the battery case. For this reason, the channel cross-sectional area on the outflow side of the channel becomes narrower from the bottom surface toward the top surface (widens from the top surface toward the bottom surface). For this reason, the flow of air from the bottom surface to the top surface is more likely to flow in the left-right direction on the bottom surface side where the channel cross-sectional area is larger than on the top surface side where the channel cross-sectional area is small. Therefore, the air flowing into the flow path from the bottom surface side is easily guided in the left-right direction, and it is difficult for the temperature adjusting air to hit the electrode terminals located on the top surface of the power storage element. It is possible to prevent the electrode terminal from dewing or the like.

It is a side view of the assembled battery provided with the temperature control structure. It is a figure which shows the top view of a spacer. It is a schematic perspective view of a cell. It is a figure which shows the laminated body electrode sheet which comprises an electric power generation element. It is the top view of a cell, and sectional drawing of each part. It is FF sectional drawing of FIG. It is an expanded sectional view of the cooling path between adjacent single electricity in an XY plane. It is an expanded sectional view of the cooling path between adjacent single electricity in the XY plane where the spacer of the modification was applied.

  Examples of the present invention will be described below.

Example 1
1 to 8 are diagrams showing the first embodiment. FIG. 1 is a side view of a battery pack 1 having the temperature control structure of the present embodiment. In FIG. 1 and the like, an X axis, a Y axis, and a Z axis are axes orthogonal to each other. The relationship among the X axis, the Y axis, and the Z axis is the same in other drawings. In this embodiment, the axis corresponding to the vertical direction is the Z axis. In the following description, the + Z direction is described as the upper direction, the −Z direction is defined as the lower direction, and the left and right direction viewed from the X direction is described as the + −Y direction (− + Y direction).

  The assembled battery (corresponding to the power storage device) 1 of this embodiment can be mounted on a vehicle and used as a power source for running the vehicle. Vehicles include hybrid cars and electric cars. A hybrid vehicle is a vehicle provided with another power source such as a fuel cell or an internal combustion engine in addition to the assembled battery 1 as a power source for running the vehicle. An electric vehicle is a vehicle including only the assembled battery 1 as a power source of the vehicle.

  The assembled battery 1 has a plurality of single cells (corresponding to power storage elements) 2. The unit cell 2 has a battery case 22 in which a power generation element is accommodated. The unit cell 2 is a so-called rectangular battery, and the battery case 22 is formed in a rectangular parallelepiped. The battery case 22 can be formed of metal, for example. As the unit cell 2, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. Moreover, an electric double layer capacitor (capacitor) can be used instead of the secondary battery.

  A plurality of single cells 2 constituting the assembled battery 1 are arranged side by side at intervals in the X direction (corresponding to a predetermined direction of the present invention). Further, a spacer 3 is disposed between the single cells 2 adjacent in the X direction. The assembled battery 1 of the present embodiment is arranged side by side so that a plurality of single cells 2 are stacked in the X direction with a spacer 3 interposed therebetween.

  A pair of end plates 4 can be provided at both ends of the assembled battery 1 in the X direction. The pair of end plates 4 sandwich a plurality of unit cells 2 constituting the assembled battery 1 and are used to give a binding force to the plurality of unit cells 2. A restraining force (not shown) that connects the pair of end plates 4 can apply a restraining force to the plurality of single cells 2 via the end plates 4.

  FIG. 2 is a plan view of the spacer 3 of this embodiment. The spacer 3 can be composed of an insulating member such as resin. As shown in FIG. 1, the spacer 3 is a partition member that forms a cooling path 9 of cooling air, which is air for temperature adjustment, between the single cells 2. The spacer 3 includes a flat plate-shaped main body portion 31 attached to the case side surface 221 on the + X direction side (right side in FIG. 1) of the unit cell 2, an upper end side protrusion 321 at the upper end of the main body portion 31, and the main body portion 31. And a lower end protrusion 322 at the lower end. The protrusions 321 and 322 are in contact with the case side surface 221 of the unit cell 2 on the −X direction side (left side in FIG. 1).

  The protrusions 321 and 322 of the spacer 3 extend in the left-right direction (left-right direction in FIG. 2) viewed from the X direction. The lower end protrusion 322 has a notch-shaped opening 323 at the center in the left-right direction. The cooling air passes between the opening 323 and the case side surface 221 and flows into the unit cells 2 from the case bottom surface 223 side.

  As shown in FIG. 2, the upper portion of the cooling path 9 is closed by the upper end side protruding portion 321, and the left and right direction is open. For this reason, the cooling air flowing in between the single cells 2 from the opening 323 flows out from between the single cells 2 from each end of the battery case 22 in the left-right direction as viewed from the X direction.

  As described above, the spacer 3 of this embodiment allows the temperature adjusting air to flow in from the case bottom 223 side of the battery case 22 constituting the single battery 2, and the left and right end portions of the single battery 2 as viewed from the X direction. A flow path for allowing air to flow out is formed. A protruding rib can be provided on the surface of the spacer 3 as an air guide member. For example, one or more ribs along the flow of the cooling air indicated by the arrows in FIG. 2 may be provided.

  Further, as shown in FIG. 1, the spacer 3 of the present embodiment forms a cooling path 9 between the unit cells 2 adjacent to each other in the X direction and the case side surface 221 of one unit cell 2. The case side surface 221 of the unit cell 2 and the main body 31 are arranged in contact with each other. The air flowing through the cooling path 9 is in contact with the case side 221 of one unit cell 2, is in contact with the main body portion 31 that is in contact with the other unit cell 2, and is located on both sides in the X direction of the cooling path 9. Heat exchange is performed directly with each other or indirectly through the main body 31.

  FIG. 3 is an external perspective view of the unit cell 2 of the present embodiment. As shown in FIG. 3, the upper surface 222 of the unit cell 2 (battery case 22) is provided with a positive electrode terminal 231 and a negative electrode terminal 232 that are connected to the power generation element 21 accommodated therein. The positive electrode terminal 231 and the negative electrode terminal 232 are electrode terminals of the unit cell 2, and are provided separately from each other in the Y direction on the upper surface 222.

  The battery case 22 can be constituted by, for example, a case main body and a lid that form a housing space for the power generation element 21. The upper surface 222 corresponds to a lid for closing the opening of the case main body for incorporating the power generation element 21 from above. The lid and the case main body can be fixed by, for example, welding, and the inside of the battery case 22 is hermetically sealed.

  FIG. 4 is a diagram illustrating an example of the laminated electrode sheet 210 constituting the power generation element 21. The multilayer electrode sheet 210 includes a positive electrode plate 211, a negative electrode plate 212, and a separator 213. Each element has a strip shape extending in the direction perpendicular to the plane of FIG. 4 and is laminated in the order of a positive electrode plate 211, a separator 213, a negative electrode plate 212, and a separator 213. Each element is impregnated with electrolyte.

  The positive electrode plate 211 is configured by laminating a positive electrode active material 211B on both surfaces of a current collector foil 211A. The positive electrode active material 211B is laminated only in a region facing the separator 213 in the current collector foil 211A. The positive electrode active material 211B is not laminated on the end side in the + Y direction of the current collector foil 211A. The negative electrode plate 212 is also configured by laminating the negative electrode active material 212B on both surfaces of the current collector foil 212A. The negative electrode active material 212B is not laminated on the end side in the −Y direction of the current collector foil 212A.

  The power generating element 21 is obtained by winding the laminated electrode sheet 210 around the Y axis as a rotation axis so that the positive electrode plate 211 is inside. The power generation element 21 has a longitudinal shape extending in the Y direction. There are a plurality of power generation units R (power storage units) on the Y direction center side of the power generation element 21. The power generation unit R is a region where the positive electrode plate 211 and the negative electrode plate 212 face each other via the separator 213, and a chemical reaction is performed when the unit cell 2 is discharged and charged.

  In the power generation element 21, the positive electrode portion Rp and the negative electrode portion Rn are located with the power generation portion R interposed therebetween. The positive electrode portion Rp is on the + Y direction side of the power generation element 21 and is a region portion where only the current collector foil 211A of the positive electrode plate 211 is wound. The negative electrode portion Rn is on the −Y direction side of the power generation element 21 and is a region where only the current collector foil 212A of the negative electrode plate 212 is wound. Since the positive electrode portion Rp and the negative electrode portion Rn are regions where only the current collector foils 211A and 212A are wound, compared with the power generation portion R wound in a state where the separator 213 and the current collector foils 211A and 212A are stacked. getting thin. The positive electrode portion Rp is electrically connected to the positive electrode terminal 231, and the negative electrode portion Rn is electrically connected to the negative electrode terminal 232.

  As shown in FIG. 3, the battery case 22 is formed in an elongated shape in the Y direction, and the positive electrode portion Rp and the negative electrode portion Rn are sandwiched with respect to the longitudinal direction of the battery case 22 with the power generation unit R interposed therebetween. The power generation element 21 is accommodated in the battery case 22 so that the longitudinal directions of the power generation elements 21 positioned substantially coincide with each other.

  The battery case 22 includes two case side surfaces 221, a case upper surface 222, a case bottom surface 223, and an end surface 224 facing in the left-right direction as viewed from the X direction, facing each unit cell 2 in the + X direction of the unit cell 2. Prepare. The center side in the left-right direction viewed from the X direction of the case side surface 221 is a flat portion 24, and both end portions in the left-right direction viewed from the X direction of the case side surface 221 are provided with stepped portions 25 recessed inside the X direction. It has been. The flat surface portion 24 and the step portion 25 can be formed on each case side surface 221 in the + −X direction (the back side and the front side in FIG. 3).

  The step portion 25 extends from the upper surface 222 provided with the positive electrode terminal 231 and the negative electrode terminal 232 of the unit cell 2 facing the bottom surface 223 of the unit cell 2 (battery case 22) toward the bottom surface 223. The step portion 25 is a taper surface portion 251 that forms a part of the case side surface 221 and extends between the flat surface portion 24 and the taper surface portion 251 and extends in a substantially vertical direction with respect to the case side surface 221. 252.

  The tapered surface portion 251 is inclined from the upper surface 222 of the battery case 22 toward the bottom surface 223. In the end region where the tapered surface portion 251 is formed, the width of the bottom surface 223 is formed smaller than the width of the top surface 222 in the X direction, and the width in the X direction is narrowed from the top surface 222 toward the bottom surface 223. .

  FIG. 5 shows a front view of the cell 2 and a cross-sectional view at each part. In FIG. 5A, the power generation element 21 housed in the single battery 2 (battery case 22) has a positive electrode portion Rp and a negative electrode portion Rn located on both sides of the central power generation portion R, respectively. In the present embodiment, the step portion 25 is formed by denting the left and right direction end portions where the positive electrode portion Rp and the negative electrode portion Rn are located, excluding the region where the power generation portion R is located, inward in the X direction. At this time, since the positive electrode portion Rp and the negative electrode portion Rn are smaller in width in the X direction than the power generation portion R as described above, the positive electrode portion Rp and the negative electrode portion Rn are formed in the end region where the step portion 25 is formed. The power generation element 21 can be accommodated in the battery case 22 so as to be arranged.

  5B is a cross-sectional view taken along the line C-C in FIG. 5A, and FIG. 5C is a cross-sectional view taken along the line D-D in FIG. Moreover, FIG.5 (d) is EE sectional drawing of FIG.5 (c). As shown in FIG. 5B, the accommodating space inside the battery case 22 sandwiched between the tapered surface portions 251 has the same width as the upper surface 222, and the inner surface of the tapered surface portion 251 and the positive electrode portion Rp and the negative electrode portion Rn are , Not touching.

  On the other hand, the width in the X direction becomes narrower from the top surface 222 to the bottom surface 223, and as shown in FIG. 5D, in the accommodating space sandwiched by the tapered surface portion 251 on the bottom surface 223 side, the inner surface of the tapered surface portion 251 and the positive electrode portion Rp. , It is narrower as the negative electrode portion Rn comes into contact. The outer periphery of the power generation element 21 can be covered with an insulating film or the like, and the power generation element 21 is accommodated in a state insulated from the battery case 22.

  Further, as shown in FIG. 5, the width in the X direction of the accommodation space inside the battery case 22 sandwiched between the flat portions 24 of the case side surface 221 is a size corresponding to the width of the power generation unit R constituting the power generation element 21. It is formed and is a substantially vertical plane in the vertical direction.

  As described above, in the cell 2 according to the present embodiment, the region of the end portion in the left-right direction of the battery case 22 where the step portion 25 is provided corresponds to the positive electrode portion Rp and the negative electrode portion Rn of the power generation element 21 accommodated therein. Yes. That is, the step portions 25 formed on both sides in the Y direction across the plane portion 24 are formed corresponding to the positive electrode portion Rp and the negative electrode portion Rn located on both sides of the power generation portion R located on the plane portion 24. ing.

  FIG. 6 is a cross-sectional view taken along line FF in FIG. As shown in FIG. 6, the stepped portion 25 of the battery case 22 is formed in a tapered shape that narrows from the upper surface 222 toward the bottom surface 223 in the end region where the left and right positive electrode portions Rp and the negative electrode portion Rn are arranged. ing. When the power generation element 21 is housed in the battery case 22, the positive electrode portion Rp and the negative electrode portion Rn are inserted along the inner surface of the taper surface portion 251 that gradually narrows, and the positive electrode portion Rp and the negative electrode portion Rn are sandwiched between the taper surface portions 251. Thus, the power generation element 21 can be accommodated in the battery case 22. Thus, the tapered surface portion 251 of this embodiment functions as a guide surface (positioning portion) when the power generation element 21 is accommodated, and the power generation element 21 can be easily inserted into the battery case 22.

  In the present embodiment, the tapered surface portion 251 in which the step portion 25 extends from the case upper surface 222 side toward the case bottom surface 223 side is formed such that the width of the bottom surface 223 is smaller than the width of the upper surface 222 in the X direction. Since the width on the upper surface 222 side is not narrowed, the opening of the battery case 22 into which the power generation element 21 is inserted and the lid for sealing the power generation element 21 can be formed in a rectangular shape and can be easily sealed.

  FIG. 7 is a view for explaining the temperature adjustment structure of the assembled battery 1 of the present embodiment. The example of FIG. 7 is a partially enlarged view of the AA cross section of FIG.

  As shown in FIG. 7, the cooling air flows between the single cells 2 through the opening 323 of the spacer 31. The cooling air that has flowed into the cooling path 9 from the bottom surface 223 side of the unit cell 2 proceeds to the left and right in the Y direction, and is discharged from the end in the left and right direction of the unit cell 2 to the outside of the unit cell 2. At this time, the flow path cross-sectional area of the cooling path 9 in the XY plane is large in the end region of the battery case 22 where the step portion 25 is formed.

  That is, since the step portion 25 of the battery case 22 is recessed inwardly, the gap between the single cells 2 is not enlarged, and the step portion 25 is enlarged by the depression (the area of the step surface 252 and the inclination of the taper surface portion 251). The area of the cooling passage 9 is enlarged.

  The temperature adjustment structure of the assembled battery 1 of the present embodiment is recessed inward at the end of the battery case 22 corresponding to the outflow side (outlet side) of the cooling path 9 formed between the single cells 2 adjacent in the X direction. Since the step portion 25 is provided, the cross-sectional area near the outlet can be increased in the cooling passage 9 for the temperature adjusting air without increasing the interval between the single cells 2. For this reason, while being able to suppress the pressure loss of air, since the area which air contacts is expanded by a level | step difference, temperature control performance can be improved.

  In the example of FIG. 7, the main body portion 31 of the spacer 3 and the step portion 25 are not in contact with each other in the end region of the battery case 22 where the step portion 25 is formed. An end region in the Y direction of the main body 31 may be formed, and for example, may be formed in a shape in which the main body 31 is brought into close contact with the stepped portion 25 as in the modification shown in FIG. In this case, the spacer 3 has a shape recessed in the X direction with respect to the cooling path 9 in the X direction, and the flow passage cross-sectional area of the cooling path 9 is enlarged by two step portions 25 at the left and right end portions. Thus, the temperature control performance can be further improved without increasing the interval between the single cells 2.

  Further, the step portion 25 is configured to be inclined from the upper surface 222 to the bottom surface 223 of the battery case 22. For this reason, the flow passage cross-sectional area on the outflow side of the cooling path 9 becomes narrower from the bottom surface 223 toward the top surface 222 (widens from the top surface 222 toward the bottom surface 223). For this reason, the flow of air from the bottom surface 223 toward the upper surface 222 is more likely to flow in the left-right direction on the bottom surface 223 side having a larger channel cross-sectional area than on the upper surface 222 side having a smaller channel cross-sectional area. Therefore, the air flowing into the cooling path 9 from the bottom surface 223 side is easily guided in the left-right direction.

  Although the upper portion of the cooling path 9 is closed by the upper end side protrusion 321 of the spacer 3 as described above, the cooling air comes into contact with the positive electrode terminal 231 and the negative electrode terminal 232 at least. Therefore, it is difficult for temperature-adjusting air to hit the positive electrode terminal 231 and the negative electrode terminal 232 positioned on the upper surface 222 of the unit cell 2. For example, dew condensation occurs when the air hits the positive electrode terminal 231 and the negative electrode terminal 232. Can be suppressed.

  Further, since air flowing into the cooling path 9 from the bottom surface 223 side is easily guided in the left-right direction, a large amount of cooling air is induced on the upper surface 222 of the unit cell 2 where the positive electrode terminal 231 and the negative electrode terminal 232 are located, and the unit cell 2 can be prevented from being actively cooled. Also in this case, the upper surface 222 side of the unit cell 2 is positively cooled, thereby suppressing the air flowing around the assembled battery 1 from contacting the positive electrode terminal 231 and the negative electrode terminal 232 to cause dew condensation or the like. Can do.

  DESCRIPTION OF SYMBOLS 1 ... Assembly battery (electric storage apparatus), 2 ... Single cell (electric storage element), 9 ... Cooling path, 22 ... Battery case, 24 ... Planar part, 25 ... Step part, 221 ... Case side surface, 222 ... Case upper surface, 223 ... Case bottom surface, 231... Positive electrode terminal (electrode terminal), 232... Negative electrode terminal (electrode terminal), 251.

Claims (1)

A temperature control structure of a power storage device in which a plurality of power storage elements are arranged in a predetermined direction,
The temperature adjusting air is introduced from the bottom surface side of the battery case that is arranged between the power storage elements adjacent to each other in the predetermined direction and constitutes the power storage element, and the left and right ends of the power storage element viewed from the predetermined direction A spacer that forms a flow path for allowing the air to flow out on the part side
The battery case has an end corresponding to the outflow side of the flow path, and extends from the top surface to the bottom surface where the electrode terminal of the storage element facing the bottom surface of the battery case is provided. A temperature control structure for a power storage device, wherein a recessed step portion is provided, and the step portion is inclined from the upper surface to the bottom surface of the battery case.

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