JP2013101820A - Secondary battery case, secondary battery and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery case having a temperature adjustment function and suppressing expansion and contraction of wall of the case caused by expansion and contraction due to charge and discharge of a power generation element housed in the battery case.SOLUTION: A secondary battery 10 is a square secondary battery having a box-shaped case 11 in which a power generation element (not shown in the figure) is housed. A positive electrode terminal 12 and a negative electrode terminal 13 are provided on an upper wall of the case 11. A plurality of ribs 15 protruding outward are formed on mutually-facing side walls 14 of the case 11. Hill parts 15a and valley parts 15b are formed on respective ribs 15 to curve along an outer surface of the side wall 14. The respective ribs 15 are formed to have a part extending in a direction obliquely crossing with a direction in which apexes of the hill parts 15 are connected in a surface parallel to the side wall 14.

Description

  The present invention relates to a case of a secondary battery, a secondary battery, and a vehicle, and more particularly to a case of a secondary battery having a temperature adjustment function, a secondary battery, and a vehicle equipped with the secondary battery.

  Secondary batteries are widely used as a power source because they can be recharged and used repeatedly. In recent years, there has been a demand for reduction in the use of fossil fuels (restriction of carbon dioxide emissions). Secondary batteries used for main and auxiliary power sources such as electric vehicles and hybrid vehicles are charged and discharged with large currents and secondary batteries. Increased capacity of batteries is required.

  However, charging / discharging with a large current involves a large amount of heat generated inside the battery, raising the battery temperature and promoting the deterioration of battery performance. In order to solve such a problem, there is a battery case in which a temperature adjustment fin is attached to the outer surface of the battery case (see, for example, Patent Document 1).

  In addition, in a configuration in which a plurality of secondary batteries (single cells) are arranged side by side, when a specific secondary battery generates heat due to overcharging or the like, this heat is applied to other secondary batteries arranged next to each other. On the other hand, a battery module that suppresses transmission is proposed (see Patent Document 2). In Patent Document 2, as shown in FIG. 8A, the battery 52 is deformed so that only a region R surrounded by a two-dot chain line located in the center is deformed in the side surface 52a of the battery case 52 of the unit cell 51. Case 52 is formed of a shape memory alloy. As shown in FIG. 8 (b), a spacer 53 having a protrusion 53a is arranged between adjacent unit cells 51. For example, a specific unit cell 51 located at the center of FIG. When heat is generated, the side surface 52 a is deformed in a direction away from the adjacent unit cell 51 in accordance with the temperature rise of the battery case 52. The protrusion 53a constitutes a moving space for the heat exchange medium.

JP 2004-213922 A JP 2010-61982

  However, the fins for temperature adjustment described in Patent Document 1 and the like are provided so as to extend in the horizontal direction or the vertical direction (height direction) of the battery case. Therefore, the effect of suppressing the deformation of the case side wall against the expansion and contraction of the power generation element (power generation element) built in the battery case tends to bend in a direction intersecting the direction in which the temperature adjusting fin extends. Only in the case, there is no effect in the case of bending along the direction in which the fin extends.

  Further, in the configuration of Patent Document 2, the spacer 53 does not function in a state where the side surface 52a is deformed due to a temperature rise. The effect on expansion and contraction depends on the strength of the shape memory alloy itself. In addition, the use of shape memory increases the cost.

  The present invention has been made in view of the above problems, and its purpose is to have a temperature adjustment function, and the wall of the case expands due to expansion / contraction associated with charging / discharging of the power generation element housed in the battery case. An object of the present invention is to provide a secondary battery case and a secondary battery that can suppress shrinkage.

  In order to achieve the above object, the invention according to claim 1 is a case of a secondary battery, wherein at least one wall is formed with a plurality of ribs protruding outward, and the rib extends along an outer surface of the wall. The ridges and valleys are formed by bending or bending.

  In the present invention, the rib formed on at least one wall of the case plays a role of suppressing the deformation of the wall with the expansion and contraction of the power generation element accommodated in the case. The power generation element is accommodated in the case so that the direction of expansion and contraction is the protruding direction of the rib formed on the wall. Since the ribs are bent or curved along the outer surface of the wall to form peaks and valleys, the rib is different in the shape extending in one direction along the outer surface of the wall. Even when trying to bend, the deformation of the wall is suppressed. The rib also serves as a temperature adjusting fin. Therefore, the case has a temperature adjustment function and can suppress the expansion and contraction of the wall of the case due to the expansion and contraction accompanying the charging / discharging of the power generation element accommodated in the case.

  The invention according to claim 2 is the invention according to claim 1, wherein the rib is formed with a plurality of crests and a plurality of troughs, and the outer surface of the wall is in the convex direction of the crests. A straight line connecting the peaks of the peaks of the ribs arranged on the outermost side and the bottoms of the valleys of the ribs arranged on the outermost side in the direction opposite to the convex direction of the peaks The area surrounded by the straight line, the straight line connecting the ends of the plurality of ribs, and the straight line connecting the other ends of the plurality of ribs is 80% or more of the surface area of the wall. Has an area. Therefore, the effect of suppressing the expansion and contraction of the wall of the case due to the expansion and contraction accompanying charging and discharging of the power generation element is improved.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the rib includes a plurality of peak portions and a plurality of valley portions.
In the plane parallel to the wall, the rib has a shape having a part extending in a direction obliquely intersecting a direction in which apexes of the peak portions are partially connected. When a method of adjusting the temperature by actively flowing a heat medium between the ribs is adopted, the rib shape has only a portion extending in a direction parallel to or perpendicular to the direction connecting the apexes of the peak portions of the rib. In the case of a shape, for example, in the case of a rectangular wave shape, the flow of the heat medium is not smoothly performed. In this invention, since the rib has a shape having a part extending in a direction obliquely intersecting with a direction in which the apexes of the crests of the rib are connected to each other, the heat medium flows smoothly. Here, the “heat medium” means a fluid that transfers heat.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the rib is formed in a shape in which curved portions are continuous. In the present invention, when the method of adjusting the temperature by actively flowing the heat medium between the ribs is adopted, the flow of the heat medium is performed more smoothly.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the wall is provided with fins between the ribs. In the present invention, the temperature adjustment function is improved by the presence of the fins.

  The invention according to claim 6 is a secondary battery in which a power generation element is accommodated in the case of the secondary battery according to any one of claims 1 to 5. The secondary battery of this invention has the effect of the case of the secondary battery of any one of Claims 1-5.

  A seventh aspect of the present invention is a vehicle equipped with the secondary battery according to the sixth aspect. Therefore, the vehicle according to the present invention can achieve the effect of the secondary battery according to the sixth aspect.

  According to the present invention, there is provided a secondary battery case having a temperature adjustment function and capable of suppressing the expansion and contraction of the wall of the case due to the expansion and contraction associated with charging and discharging of the power generation element accommodated in the battery case, and A secondary battery can be provided. Moreover, the vehicle carrying the said secondary battery can be provided.

(A) is a side view of the secondary battery of 1st Embodiment, (b) is a schematic perspective view. The typical fragmentary sectional view of the assembled battery by which the some secondary battery was accommodated in the case. The side view of the secondary battery of 2nd Embodiment. The schematic perspective view of a fin. (A), (b) is a schematic diagram which shows the shape of the rib of another embodiment. (A), (b) is a schematic perspective view which shows the shape of the fin of another embodiment. (A) is sectional drawing of another embodiment, (b) is a front view of the secondary battery of another embodiment, (c) is a typical fragmentary sectional view of the assembled battery using the secondary battery. (A) is a schematic diagram which shows the part which a secondary battery receives repeatedly stress with expansion | swelling contraction of an electric power generation element, (b) is a partial side view of a prior art.

(First embodiment)
Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIGS. 1A and 1B, a secondary battery 10 as a single battery is a square secondary battery having a square box-like case 11 in which a power generation element (not shown) is accommodated. A positive electrode terminal 12 and a negative electrode terminal 13 are provided on the upper wall. In the case 11, a plurality of ribs 15 projecting outward are formed on opposing side walls 14 as walls, and each rib 15 is curved along the outer surface of the side wall 14 to form a peak portion 15a and a valley portion 15b. 15 is formed in the shape which has a part extended in the direction which cross | intersects the direction which tied the vertex of the peak part 15a in a part in the horizontal surface with the side wall 14 diagonally. In this embodiment, each rib 15 is formed in a shape having a portion that extends in a direction that obliquely intersects the left-right direction of the side wall 14. Each rib 15 is formed in a shape in which curved portions are continuous. The curved portion is formed in a semicircular arc shape having the same radius. The case 11 may be made of metal, resin, or other material.

  As shown in FIG. 1A, on the outer surface of the side wall 14, a straight line L1 connecting the vertices of the crests 15a of the ribs 15 arranged on the outermost side in the convex direction of the crests 15a, and the convexity of the crests 15a. A straight line L2 connecting the bottoms of the valleys 15b of the ribs 15 arranged on the outermost side in the direction opposite to the direction, a straight line L3 connecting one ends of the plurality of ribs 15, and the other ends of the plurality of ribs 15. The area surrounded by the straight line L <b> 4 connecting the parts has an area of 80% or more of the surface area of the side wall 14.

  In addition, for example, as shown in FIG. 1A, an arbitrary rib 15 having an adjacent rib 15 on the upper side draws a tangent L common to the peak portion 15a on the third rib 15 from the upper side. The tangent line L is arranged so as to intersect with the adjacent rib 15 on the upper side of the rib 15. That is, each rib 15 is arranged so that the top of each peak 15a of any rib 15 where the adjacent rib 15 exists on the upper side is located above the bottom of the valley 15b of the adjacent rib 15 on the upper side. Yes. The rib 15 may be configured to be integrally formed with the case 11 or may be configured such that a separately formed member is attached to the case 11 with an adhesive or the like.

  As shown in FIG. 2, the secondary battery 10 configured as described above is used as an assembled battery (battery module) 20 including a plurality of secondary batteries 10. The assembled battery 20 includes a housing 22 having an accommodating portion 21 that accommodates a plurality of secondary batteries 10 in parallel with each other. A plurality of secondary batteries 10 are arranged in the housing portion 21 in parallel with the ribs 15 in contact with each other. The plurality of secondary batteries 10 constituting the assembled battery 20 are all connected by electrically connecting the positive terminal 12 and the negative terminal 13 of the adjacent secondary battery 10 via a bus bar (not shown) as a wiring member. Secondary batteries 10 are connected in series.

  The housing 22 is formed with a heat medium flow path through which a heat medium for adjusting the temperature for holding the secondary battery 10 within a predetermined temperature range suitable for the operation thereof. It is provided in a part of the road. In FIG. 2, the heat medium flow path allows the heat medium to flow in a direction perpendicular to the paper surface, that is, along the side wall 14 of the case 11 of the secondary battery 10. For example, the housing 22 includes an intake duct and an exhaust duct, and air is supplied into the housing from the intake duct and exhausted from the exhaust duct by air blowing means such as a fan and a blower.

Next, the operation of the secondary battery 10 configured as described above will be described.
When the assembled battery 20 is used, a cooling heat medium is supplied to the housing 22, and the heat medium flows along the side wall 14 of the case 11 of each secondary battery 10 housed in the housing portion 21. The heat generated during charging or discharging of the secondary battery 10 is transmitted to the heat medium through the side wall 14 and the rib 15 of the case 11, and is taken away by the discharge from the housing part 21 of the heat medium. To be cooled. The secondary battery 10 is kept within a predetermined temperature range suitable for its operation, and is prevented from becoming a high temperature that promotes deterioration of battery performance.

  When the assembled battery 20 is used, the secondary battery 10 generates a large amount of heat during rapid charge or rapid discharge, and the expansion and contraction of the power generation element housed inside the case increases. At this time, the ribs 15 formed on the opposing side walls 14 of the case 11 serve to suppress the side walls 14 from being deformed as the power generating element expands and contracts. In the case where the shape of the rib 15 is a shape that extends straight in the left-right direction of the side wall 14 (perpendicular to the paper surface in FIG. 2), the effect of suppressing the deformation of the side wall 14 when the side wall 14 tends to bend in the vertical direction. Is not demonstrated. However, each rib 15 has a shape in which the shape of the rib 15 extends in a direction obliquely intersecting the direction connecting the vertices of the peaks 15a, so that the rib 15 is either in the horizontal direction or the vertical direction of the side wall 14. Unlike the case of the shape extending along the direction, the deformation of the side wall 14 is suppressed even when the side wall 14 tends to bend in any direction. Further, on the outer surface of the side wall 14, the straight line L1 connecting the vertices of the crests 15a of the ribs 15 arranged on the outermost side in the convex direction of the crests 15a and the outermost side in the direction opposite to the convex direction of the crests 15a A straight line L2 connecting the bottoms of the troughs 15b of the ribs 15 arranged in the straight line L3, a straight line L3 connecting one ends of the plurality of ribs 15, and a straight line L4 connecting the other ends of the plurality of ribs 15. The area surrounded by, has an area of 80% or more of the surface area of the side wall 14. Therefore, even if rapid charging and rapid discharging are repeated, the deterioration of the side wall 14 is prevented and durability is improved.

  Further, the assembled battery 20 is housed in the housing portion 21 of the housing 22 in such a manner that the secondary batteries 10 arranged adjacent to each other are in contact with the ribs 15 provided on the side walls 14 thereof. When the power generation heat element of the secondary battery 10 expands, the side wall 14 is prevented from being deformed so as to be bent outward by the action of the rib 15 of the secondary battery 10 located adjacent thereto.

According to this embodiment, the following effects can be obtained.
(1) The case 11 of the secondary battery 10 is formed with a plurality of ribs 15 protruding outward on the opposite side walls 14, and each rib 15 is bent or curved along the outer surface of the side wall 14 and A trough portion 15b is formed. Therefore, the case 11 has a temperature adjustment function, and can suppress the expansion and contraction of the side wall 14 of the case 11 due to the expansion and contraction accompanying the charging and discharging of the power generation element accommodated in the case 11.

  (2) On the outer surface of the side wall 14, the straight line L1 connecting the vertices of the ridges 15a of the ribs 15 arranged on the outermost side in the convex direction of the ridges 15a and the most in the direction opposite to the convex direction of the ridges 15a A straight line L2 connecting the bottoms of the valleys 15b of the ribs 15 arranged outside, a straight line L3 connecting one ends of the plurality of ribs 15, and a straight line L4 connecting the other ends of the plurality of ribs 15. And the area of the region surrounded by is 80% or more of the surface area of the side wall 14. Therefore, the effect which suppresses that the side wall 14 of the case 11 expands and contracts by expansion / contraction accompanying charging / discharging of an electric power generation element improves.

  (3) On the surface parallel to the side wall 14, the rib 15 has a shape having a portion extending in a direction obliquely intersecting with a direction in which apexes of the mountain portions 15a are connected to each other. When a method of adjusting the temperature by actively flowing a heat medium between the ribs 15 is adopted, the shape of the ribs 15 extends in a direction parallel to or perpendicular to the direction connecting the apexes of the crests 15a of the ribs 15. In the case of a shape having only a portion, for example, in the case of a rectangular wave shape, the flow of the heat medium is not smoothly performed. However, since the rib 15 has a shape having a part extending in a direction obliquely intersecting with a direction in which the apexes of the peak portions 15a are connected to each other, the heat medium flows smoothly.

  (4) The rib 15 is formed in a shape in which curved portions are continuous. Therefore, when the method of adjusting the temperature by actively flowing the heat medium between the ribs 15 is adopted, the flow of the heat medium is performed more smoothly.

  (5) The assembled battery 20 is accommodated in the accommodating portion 21 of the housing 22 in a state where the ribs 15 provided on the side wall 14 of the case 11 are in contact with each other. Therefore, the side walls 14 are curved outward when the power generation element of the secondary battery 10 is expanded, as compared to the case where the adjacent secondary batteries 10 are accommodated in the accommodating portion 21 with the ribs 15 not contacting each other. Is prevented from being deformed.

(6) When the secondary battery 10 is mounted on a vehicle and used, the vehicle can obtain the above-described effects in the secondary battery 10.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in that fins are provided on the side wall 14 in order to enhance the temperature adjustment function. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, fins 16 (shown in FIG. 4) are provided on the side wall 14 in a region A surrounded by a two-dot chain line between the ribs 15. As the fins 16, offset fins are used. In this embodiment, as shown in FIG. 4, a thin metal plate formed by bending a rectangular wave having a constant height and width is an adjacent rectangular wave. Are arranged so as to be repeated in a state in which the pitch is shifted by a half pitch. The number of rows of fins 16 and the number of irregularities present in one row are changed depending on the size of the region A. The fin 16 is formed to have a height lower than that of the rib 15 so as not to interfere with the fin 16 provided in the adjacent secondary battery 10 when the side wall 14 is curved and deformed outward.

Therefore, the secondary battery 10 of this embodiment can obtain the following effects in addition to the effects (1) to (5) of the first embodiment.
(7) Fins 16 are provided between the ribs 15 on the side wall 14. Accordingly, the presence of the fins 16 improves the temperature adjustment function.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The rib 15 only needs to be bent or curved along the outer surface of the wall to form peaks and valleys, and the rib 15 is not limited to a shape in which the curved portion is continuous, but a shape in which the straight portion is bent and continuous. But you can.

  The rib 15 is only required to be formed in a shape having a part extending in a direction obliquely intersecting a direction in which the vertices of the ridges 15a are partially connected, and a semicircular curved portion is continuous. It does not restrict to the shape to do. For example, it may have a sine wave shape, as shown in FIG. 5 (a), or a straight portion 15c that extends obliquely may be bent in a wave shape, or a straight portion that extends in the left-right direction as shown in FIG. 5 (b). 15d may be connected via a straight line portion 15e extending in the vertical direction and a straight line portion 15c extending obliquely.

  The rib 15 may have a rectangular wave shape in which the rib (the side wall 14) is parallel to the wall (side wall 14) and does not have a portion extending in a direction obliquely intersecting the direction connecting the peaks 15a. However, in order for the rib 15 to guide the flow of the heat medium, a portion extending in a direction obliquely intersecting with a direction in which the vertices of the ridges 15a are partially connected on a wall (side wall 14) and a horizontal surface. The shape having is preferable.

O Since the power generation element housed in the case 11 of the secondary battery 10 has a large expansion at the center, at least two ribs 15 may be provided only near the center of the side wall 14.
The rib 15 is not limited to a configuration in which only a plurality of ribs having the same shape are provided, and may be provided in a state where ribs 15 having different shapes are mixed.

The rib 15 is not limited to the configuration extending in the left-right direction of the side wall 14, and may be configured to extend in the vertical direction of the side wall 14 when the heat medium flows in the vertical direction of the side wall 14.
The rib 15 is not necessarily limited to a configuration in which each rib 15 extends in the left-right direction or the vertical direction of the side wall 14 over substantially the entire length. For example, a plurality of ribs 15 that are shorter than substantially the entire length of the side wall 14 in the left-right direction or the up-down direction may be provided in a state where some of them overlap when viewed from the up-down direction or the left-right direction.

  The wall in which the rib 15 is formed is not limited to the side wall, and may be a wall having a wall surface facing the expansion and contraction direction of the power generation element housed in the case 11, and depending on the case, the rib may be formed on the front wall and the rear wall. 15 may be formed.

The rib 15 should just be provided in the at least 1 wall, and may be provided only in one wall, not provided in both of the opposing walls.
The offset fins constituting the fin 16 are not limited to the shape shown in FIG. 4, and for example, as shown in FIG. 6 (a), a shape in which two adjacent rectangular waves are paired, or FIG. 6 (b). As shown in FIG. 6, the adjacent rectangular waves may be continuously formed in a state where they are alternately shifted by a half pitch.

The fin 16 is not limited to the offset fin, and may have a shape in which a flat plate or a corrugated plate protrudes.
○ The secondary battery 10 is not limited to a case where a plurality of secondary batteries 10 are used as a unit battery and used as a single battery, but as shown in FIG. You may use it in the state accommodated in the housing 22 in which the heat-medium flow path through which the heat medium which performs temperature adjustment for hold | maintaining in the predetermined temperature range suitable for operation | movement was formed.

  In the case of the secondary battery 10 that is not used alone but is used as a single battery of the assembled battery 20, the ribs 15 are not provided on both side walls 14 of the case 11, as shown in FIG. You may provide only in the side wall 14. FIG. As shown in FIG. 7C, the secondary battery 10 is adjacent to the side wall 14 on the side where the rib 15 of each secondary battery 10 accommodated in the accommodating portion 21 of the housing 22 does not exist. Are accommodated in a state in which the ribs 15 abut. And the secondary battery 10 by which the rib 15 was formed in the both-sides wall 14 is used for the secondary battery 10 arrange | positioned at the edge part side which the accommodating part 21 is not shown in figure. In this case, when the side wall 14 is to be bent outward due to expansion of the power generation element of the secondary battery 10, the side wall 14 without the rib 15 is formed by the rib 15 provided on the side wall 14 of the adjacent secondary battery 10. The deformation is suppressed.

  The case 11 only needs to have a shape having opposing side walls 14, and the case 11 is not limited to a square box shape for a rectangular secondary battery. For example, the corners of the four corners of the square box-like case 11 are arcuate. The formed long cylindrical shape may be sufficient.

The assembled battery 20 is not limited to a configuration in which a plurality of secondary batteries 10 are connected in series, and may have a configuration in which a plurality of secondary batteries 10 are connected in parallel.
The housing 22 that constitutes the assembled battery 20 includes housing portions 21 that house a plurality of secondary batteries 10 in a plurality of rows instead of one row, and the ribs 15 abut against the adjacent secondary batteries 10 in each row. You may arrange in a state.

  The assembled battery 20 is not limited to a configuration in which the plurality of secondary batteries 10 are accommodated in the accommodating portion 21 of the housing 22 to which the heat medium is supplied and discharged, and a frame that can hold the plurality of secondary batteries 10 in a predetermined position. It is good also as a structure supported by. And you may make it blow the air as a heat medium toward the secondary battery 10 by ventilation means, such as a fan and a blower.

○ The heat medium is not limited to a gas such as air, and an electrically insulating liquid may be used. When a liquid is used as the heat medium, the heat medium is circulated.
The following technical idea (invention) can be understood from the embodiment.

  (1) A plurality of the secondary batteries in which the power generation elements are accommodated in the case of the secondary battery according to any one of claims 1 to 5 are accommodated in a state in which the secondary batteries are accommodated in a mutually parallel state. An assembled battery in which secondary batteries are arranged in parallel with the ribs in contact with each other.

  L1, L2, L3, L4 ... straight line, 10 ... secondary battery, 11 ... case, 14 ... side wall as a wall, 15 ... rib, 15a ... mountain part, 15b ... valley part, 16 ... fin.

Claims (7)

  A case of a secondary battery, wherein at least one wall is formed with a plurality of ribs protruding outward, and the ribs are bent or curved along the outer surface of the wall to form peaks and valleys. Rechargeable battery case. The rib is formed with a plurality of crests and a plurality of troughs,
On the outer surface of the wall, the straight line connecting the vertices of the crests of the ribs arranged on the outermost side in the convex direction of the crests is arranged on the outermost side in the direction opposite to the convex direction of the crests. A region surrounded by a straight line connecting the bottoms of the valleys of the ribs, a straight line connecting the ends of the plurality of ribs, and a straight line connecting the other ends of the plurality of ribs. The case of the secondary battery according to claim 1, which has an area of 80% or more of the surface area of the wall. The rib is formed with a plurality of crests and a plurality of troughs,
3. The secondary according to claim 1, wherein the rib has a shape having a portion extending in a direction obliquely intersecting with a direction in which apexes of the mountain portions are connected to each other on a plane parallel to the wall. Battery case.   The case of the secondary battery of any one of Claims 1-3 in which the said rib is formed in the shape where a curve part continues.   The case of the secondary battery according to claim 1, wherein fins are provided between the ribs on the wall.   The secondary battery by which the electric power generation element was accommodated in the case of the secondary battery of any one of Claims 1-5.   A vehicle equipped with the secondary battery according to claim 6.