JP2012064357A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variation of temperatures between a plurality of cells in a battery module which is configured by stacking the plurality of cells in parallel and coupling end plates respectively provided on their outer faces in the direction in which they are lined up in parallel with a coupling member.SOLUTION: A battery module includes: a plurality of cells 10 stacked separately from one another in parallel; and a pair of end plates 50 and 51 interposing the plurality of cells 10 from their outsides in the direction in which they are lined up in parallel. Heat insulation members 20 are provided between the cells 10 and the respective pair of end plates 50 and 51 for insulating them from heat.

Description

  The present invention mainly relates to a battery module constituting a secondary battery used as a power source for driving a motor of a hybrid vehicle or an electric vehicle.

  Conventionally, as the battery module, a plurality of rectangular unit batteries 11 (cells) arranged in parallel, a partition wall that maintains a constant interval between the unit batteries, and an end that is in close contact with the outer surface of the outermost unit battery 11 A battery assembly (battery module) including a plate and a connecting rod 30 that is integrally coupled to the plate is known (see Patent Document 1 described later).

JP 2006-310309 A

  By the way, in such a battery assembly (battery module), it is desirable that all of the plurality of unit batteries (cells) arranged in parallel are maintained at substantially the same temperature, but the end plate has a thermal mass as compared with the unit battery. Therefore, the unit cell adjacent to the end plate is deprived of heat by the end plate and is cooled lower than the remaining unit cells, resulting in variations in the temperature between the plurality of unit cells. Although there is a problem that it causes deterioration of the performance of the body, the conventional means does not have technical means for solving such a problem.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a novel battery module capable of suppressing temperature variations between a plurality of cells constituting the battery module.

In order to achieve the object, the invention according to claim 1 includes a plurality of cells stacked in parallel at intervals, and
In the battery module comprising a pair of end plates sandwiching the plurality of cells from the outside in the parallel direction thereof,
A heat insulating member is provided between the cell and the pair of end plates to insulate them.

  In order to achieve the object, the invention according to claim 2 is the one according to claim 1, wherein the heat insulating member is constituted by a plate-like member, and the plate-like member includes the cell and a pair of end plates. A cooling passage through which the refrigerant flows is formed.

  In order to achieve the object, the invention according to claim 3 is the one according to claim 1 or 2, wherein a holder is provided between the plurality of cells to maintain a constant distance between adjacent cells. The holder is the same as the heat insulating member, and the cell and the pair of end plates have held portions having substantially the same shape held by the heat insulating member and a holding member provided in the holder. Yes.

  In order to achieve the above object, according to a fourth aspect of the present invention, in the third aspect of the present invention, the surfaces of the pair of end plates facing the heat insulating member are formed in a lattice shape. It is said.

  In order to achieve the above object, the invention according to claim 5 is the invention according to claim 3 or 4, wherein one of the pair of end plates is provided on a surface opposite to the surface facing the heat insulating member. The voltage sensor assembly is arranged, and the end plate has a larger thermal conductivity and volume than the voltage sensor assembly.

  According to the first aspect of the present invention, since the heat insulating layer is formed by the heat insulating member between the cell and the end plate, the cell adjacent to the end plate having a large thermal mass is supercooled compared to the remaining cells. Thus, variation in cell deterioration due to temperature variation among a plurality of cells can be prevented, and the performance of the battery module can be improved and the life can be extended.

  According to the invention described in claim 2, since the heat insulating member is formed of a plate-like member, the interval between the plurality of cells is prevented from being increased by narrowing the interval between the plurality of cells. Moreover, the heat insulation effect can be further enhanced by circulating the refrigerant through the cooling passage provided in the heat insulation member.

  Further, according to the third aspect of the present invention, the cells can be held at a constant distance by the holder and can be insulated from each other, and since the holder is the same as the heat insulating member, the number of parts can be reduced. In addition, the cell and the pair of end plates can be held by the same heat insulating member and holder having substantially the same shape to be held, so that the holding structure can be simplified and securely held. can do.

  Furthermore, according to the invention described in claim 4, since the surfaces of the pair of end plates facing the heat insulating member are formed in a lattice shape, the heat transfer area between the end plates and the cells is reduced, and the space between them is reduced. The heat insulation effect can be enhanced.

  According to the fifth aspect of the present invention, the voltage sensor assembly is arranged on one surface of the end plate opposite to the surface facing the heat insulating member, and the end plate is more than the voltage sensor assembly. Since the thermal conductivity and the volume are large, heat is generated from the voltage sensor assembly that easily generates heat to the end plate having a large thermal mass, and the voltage sensor assembly can be prevented from being overheated.

Whole exploded perspective view of the battery module of the present invention 1 is a side view of the battery module taken along line 2 in FIG. 2 is a plan view of the battery module as viewed in the direction of arrow 3 in FIG. The bottom view of the battery module seen from the arrow 4 in FIG. Enlarged view of the phantom line encircled portion in FIG. The perspective view of the holder of 6 arrows of FIG. FIG. 7 is an enlarged sectional view taken along line 7-7. FIG. 7 is an enlarged sectional view taken along line 8-8. 1 is an enlarged perspective view taken along arrow 9 in FIG. FIG. 9 is an enlarged sectional view taken along line 10-10.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention illustrated in the accompanying drawings.

  As shown in FIG. 1, the battery module according to the present invention is provided with a plurality of rectangular cells 10 arranged in parallel at intervals, and between the cells 10 and outside the outermost cell 10. A plurality of holders 20, one square end plate 50 provided outside one outermost holder 20, and the other square end plate provided outside the other outermost holder 20 ( A plurality of cells 10 and a holder 20 which are stacked in close contact with each other, and are sandwiched between one and the other end plates 50 and 51, and the end plates 50 and 51 are The upper connection frame 60 and the lower connection frame 70 are tightened together. Further, a voltage sensor assembly (voltage sensor) 90 is coupled to the outside of the one end plate 50, 51.

  The rectangular cell 10 has a conventionally known structure and is formed in a flat rectangular parallelepiped shape. Positive and negative electrode terminals 11 and 12 are projected on the left and right surfaces of the rectangular cell 10, and an explosion-proof valve is provided at the center. A valve port 14 (FIG. 7) is provided which is closed by 13.

  The holder 20 is interposed between the adjacent cells 10 in parallel, with a predetermined interval between the cells 10 to hold the cells 10 and to maintain a heat insulating space with a constant interval therebetween. Hereinafter, the structure of the holder 20 will be described mainly with reference to FIGS.

  The main part 21 of the holder 20 is formed of a synthetic resin plate in the shape of a square plate having approximately the same size as the cell 10. The main portion 21 of the holder 20 has a plurality of first ridges 22 and a plurality of second ridges 23 alternately in the vertical direction, each having a U-shaped longitudinal section extending parallel to each other in the horizontal direction. Each of the first and second ridges 22 and 23 is formed with a transverse cooling passage 24 having a concave cross section that is open at both left and right ends. Yes. The main portion 21 is provided with a plurality of circular air vents 25 for evenly circulating a coolant such as cooling air over the entire surface. Specifically, these air vents 25 are shown in FIG. 6, the upper and lower portions of the main portion 21 and the first and second protrusions 22 and 23 are formed respectively, and these ventilation holes 25 are turbulent to the refrigerant flowing on the front and rear surfaces of the holder 20. And the cooling effect of the cell 10 is enhanced.

  As shown in FIGS. 5 and 6, an intermediate portion in the vertical direction of the outer surface of the plurality of first protrusions 22 and second protrusions 23 located in the middle of the main body portion 21 of the holder 20, The ribs 26 and 27 extending in the longitudinal direction are integrally formed to project. These ribs 26 and 27 are used to reinforce the holder 20 itself and maintain a predetermined distance between the adjacent cells 10 with the holder 20 in between when the battery module is assembled. 7 and 8, as shown in FIGS. 7 and 8, the height of the rib 27 corresponding to the central portion of the main portion 21 is the highest (a), and the rib increases as it goes outward in the parallel direction thereof. The heights (b, c) of 26 and 27 are sequentially reduced (a> b> c), and the height along the length of each rib 26, 27 itself is the highest (b, c). The tip is gradually lower toward the end of the main portion 21, and the tip is the lowest (a ', b'). Thus, by setting the height of the ribs 26, 27, When the battery module is assembled, the cell 20 is held by the holder 20. , In particular to be able to suppress the bulging deformation of the central portion.

  As clearly shown in FIGS. 5 and 6, holding members 30 are respectively fixed to the four corners of the main portion 21 of the holder 20. Each holding member 30 is made of an angle member, and protrudes outward from the front and rear surfaces of the main body portion 21 of the holder 20. The angle recesses 31 have the cell 10 or the end plate 50 when the battery module is assembled. , 51 are respectively engaged with the common held portions 10A, 10A; 10A, 50A; 10A, 51A formed at the four corners, and the plurality of cells 10 and the end plates 50, 51 are displaced from each other. Without being able to align them to the regular assembly position. In addition, a holding piece 32 is bent at an intermediate portion on one side of the main body 21 of the holder 20, and the holding piece 32 is configured to hold the side surface of the cell 10.

  As shown in FIGS. 5 and 7, a holder tongue piece 33 is integrally formed at the center of the upper surface of the holder 20 in the width direction. The holder tongue 33 is bent substantially at right angles to the front and rear surfaces of the holder 20, that is, substantially horizontally, and has a standing wall 37 extending in the direction of the cell 10. When the battery module is assembled, there is a gap 34 on the upper surface of the explosion-proof valve 13 that closes the valve port 14 at the center of the upper surface of the adjacent cell 10. Covered. In addition, a funnel-shaped inclined surface 15 that is inclined upward toward the upper surface of the cell 10 is formed at the periphery of the valve port 14. And after receiving the ejection body, such as the gas of the electrolyte solution discharged when the explosion-proof valve 14 is opened, by the holder tongue piece 33, the ejection body, such as the liquefied electrolytic solution, is transmitted through the valve port 14. It is made to return to the inside of the cell 10, and further, the sprayed body is stopped in the gap 34 so that the spray body can be prevented from scattering to the outside (see FIG. 7).

  Further, a positioning projection 35 that can be fitted into a positioning hole 61 of the upper connection frame 60, which will be described later, is integrally projected on the upper surface of the holder tongue 33. An engaging piece 36 that can engage with the upper surface of the adjacent cell 10 is integrally provided at the base of the holder tongue 33.

  As shown in FIG. 6, a mounting frame 38 for the thermistor T, which will be described later, is integrally formed at the center of the lower surface of the holder 20 in the width direction. The mounting frame 38 is bent substantially at right angles to the same direction as the holder tongue piece 33, that is, substantially horizontally, and extends in a cantilever manner in one of the front and rear directions of the holder 20.

  Next, the structure of the mounting frame 38 will be described with reference mainly to FIGS. 6, 9 and 10. The thermistor T for measuring the temperature of the cell 10 is selectively attached to and detached from the mounting frame 38. A thermistor mounting portion 39 for mounting is provided. A pair of guides 40 for guiding the thermistor T are integrally provided in parallel on the outer surface of the mounting frame 38, and a pair of holding pieces 41 for holding the thermistor T is provided adjacent to the guides 40. Further, a pair of engaging pieces 42 that engage with the lower surface of the cell 10 adjacent to the holder 20 and prevent the thermistor T from coming off extend on the opposite side of the holding piece 41 at the base of the mounting frame 38. . Further, the pair of guides 40 are integrally formed with a pair of positioning projections 43 that can be fitted into positioning holes 71 of a lower connection frame 70 described later. As shown in FIG. 9, the thermistor T is inserted between a pair of guides 40 and held at a predetermined position by a pair of holding pieces 41, and its temperature sensing part comes into contact with the lower surface of the cell 10, Measure the temperature. The position of the thermistor T can be easily confirmed from the outside by visual inspection. The lead wire 95 connected to the thermistor T is connected to a voltage sensor assembly 90 described later.

  As shown in FIG. 1, a pair of end plates 50 and 51 that are stacked in parallel and tightly clamp a plurality of cells 10 and holders 20 from the outside are formed in a flat rectangular parallelepiped that is substantially the same type as the cells 10 and holders 20. The outermost cells 10 are arranged on both outer surfaces through the holder 20 functioning as a heat insulating member.

  Each of the pair of end plates 50 and 51 is made of metal (for example, made of a magnesium alloy), and the opposed surface to the holder 20 is formed in a lattice shape so that the heat transfer area is small and the heat dissipation is good. Between the inner surfaces of the end plates 50 and 51 and the cell 10, the holders 20 functioning as heat insulating members are respectively interposed so that excessive cooling of the cell 10 can be prevented.

  The one and the other end plates 50 and 51 forming a pair are integrally connected by an upper connection frame 60 and a lower connection frame 70 which will be described later. As shown in FIGS. 1 and 3 and 4, first and second fixing portions 52 u and 53 u and first and second fixing portions 52 u and 53 u for connecting the upper connecting frame 60 are formed on the upper surfaces of the pair of end plates 50 and 51. The fixing portions 54u and 555u are integrally provided, and the first and second fixing portions 52d and 53d and the first fixing portions 52d and 53d for connecting the lower connection frame 70 are connected to the lower surfaces of the pair of end plates 50 and 51, respectively. The 1st and 2nd fixing | fixed part 54d and 55d are each provided integrally. Each of the first fixing portions 52u, 54u (52d, 54d) and the second fixing portions 53u, 55u (53d, 55d) is formed of a square block body, and the center portion of the end plates 50, 51 in the width direction. The connecting holes h are respectively formed in the center of these fixing portions. Each connection hole h passes through the centers of the plurality of cells 10, the holder 20, and the end plates 50, 51, and is substantially orthogonal to the center line CC extending in the parallel direction thereof. It is directed inward in the vertical direction of 51. As shown in FIG. 3, the distance D1 from the center of the first fixing parts 52u, 54u (52d, 54d) and the second fixing parts 53u, 55u (53d, 55d) to the center line CC is The distance D2 is smaller than the distance D2 from the center of the fixed portion to the outermost surface of the end plates 50 and 51 (D1 <D2).

  As shown in FIGS. 1 and 3, the upper connecting frame 60 is formed in an elongated shape by a metal plate, and includes a flat portion 63 in which a plurality of positioning holes 61 are arranged and a plurality of ribs 62 are raised in the longitudinal direction. The connection piece 65 is formed with a flange piece 64 standing upright on both sides of the flange piece 64 and having a high rigidity with a U-shaped cross section, and has a pair of bolt holes 67 formed at both ends thereof. 66 are integrally projected in the lateral direction.

  As shown in FIG. 3, the upper connection frame 60 passes through the centers of the plurality of cells 10 and the holders 20 stacked in parallel with each other, and extends in the parallel direction. The plurality of positioning holes 61 are arranged along the C, and the positioning projections 35 on the upper surfaces of the holders 20 are fitted into the positioning projections 35 to position the upper connection frame 60 with respect to the cells 10 and the holder 20. The connection ear pieces 65 and 66 at both ends of the upper connection frame 60 are respectively positioned on the first fixing portions 52u and 54u and the second fixing portions 53u and 55u on the upper surfaces of the pair of end plates 50 and 51, respectively. 68 is screwed into the connection holes h of the first fixing parts 52u and 54u and the second fixing parts 53u and 55u through the bolt holes 67 of the connection ear pieces 65 and 66, respectively, the upper connection frame 60 is The upper portions of the end plates 50 and 51 can be tightly connected together.

Further, as shown in FIG. 3, the horizontal width d ₁ of the flat portion 63 of the upper connection frame 60 is formed wider than the horizontal width d ₂ of the holder tongue piece 33, and the flat portion 63 is formed of the holder tongue piece 33. The entire upper surface is covered. As a result, the scattering of the ejected body such as the electrolyte gas discharged to the explosion-proof valve 13 when the valve is opened is primarily prevented by the holder tongue 33 as described above, and further the secondary by the upper connecting frame 60. Can be prevented.

  On the other hand, as shown in FIGS. 1 and 4, the lower connection frame 70 is formed in substantially the same shape as the upper connection frame 60, and a flat portion 72 in which a plurality of positioning holes 71 are arranged in two rows, The flange pieces 73 that stand integrally on both sides thereof and are formed in a reverse U-shape in cross section, have high rigidity, and connecting ear pieces 75 and 76 that form a pair with bolt holes 74 formed at both ends thereof. It is formed to project integrally in the lateral direction.

  As shown in FIGS. 1 and 4, a plate-like cover plate 78 is superimposed on the lower surface of the plurality of cells 10 and the holder 20 that are alternately stacked in parallel. Further, the lower surface of the cover plate 78 has a rib-like shape. The lower connection frame 70 is superimposed on the lower surfaces of the plurality of cells 10 and the holder 20 via the cover plate 78 and the plate spring 80, and the lower connection frame 70 allows a pair of plate springs 80 to be formed. The lower surfaces of the end plates 50 and 51 are connected together. As shown in FIG. 4, the lower connection frame 70 extends along the center line CC along the lower surface of the plurality of cells 10 and the holder 20 stacked in parallel with the cover plate 78 and the spring plate 80 interposed therebetween. Arrange them. The positioning projection 43 of the mounting frame 38 is inserted into the positioning hole 71 after passing through the through hole 79 and the spring plate 80 of the cover plate 78 (see FIG. 5). Thereby, the plurality of cells 10 and the holder 20 and the lower connection frame 70 are positioned. The connecting ear pieces 75 and 76 at both ends of the lower connecting frame 70 are positioned on the first fixing portions 52d and 54d and the second fixing portions 53d and 55d on the lower surfaces of the pair of end plates 50 and 51, and the connecting bolt 77 is attached. The lower connection frame 70 is connected to the pair of ends by screwing the bolts 74 of the connection ear pieces 75 and 76 into the connection holes h of the first fixing parts 52d and 54d and the second fixing parts 53d and 55d. The lower portions of the plates 50 and 51 can be tightly coupled together.

  Thus, the pair of end plates 50 and 51 that sandwich the plurality of cells 10 and the holder 20 stacked in parallel with each other are integrally tightened by the upper connection frame 60 and the lower connection frame 70. In this state, as shown in FIG. 3, the first fixing portions 52u, 54u (52d, 54d) and the second fixing portions 53u, 55u (53d, 55d) of the pair of end plates 50, 51 are provided. The distance D1 from the center to the center line C-C is smaller than the distance D2 from the center of the fixed portion to the outermost surface of the pair of end plates 50 and 51 (D1 <D2). Due to the deterioration of the plurality of cells 10, the connecting frame 60 and the lower connecting frame 70 can effectively suppress the bulging deformation of those cells (the largest bulging deformation at the central portion).

  As shown in FIG. 1, a voltage sensor assembly 90 is overlapped and fixed on the outer surface of one end plate 50. The voltage sensor assembly 90 is a flat rectangular parallelepiped that is slightly smaller than the end plate 50, has a smaller thermal conductivity and volume than the end plate 50, and mounting pieces 91 and 92 project from the diagonal positions. Yes. Further, mounting bosses 81, 82 corresponding to the mounting pieces 91, 92 are projected at diagonal positions of one end plate 50, and the mounting pieces 91, 92 and the mounting bosses 81, 82 are connected by connecting bolts 93. The voltage sensor assembly 90 is fixed to the outer surface of one end plate 50 with a gap.

  The end plate 50 is also used as a rigid member of the case of the voltage sensor assembly 90 and serves to improve the rigidity of the voltage sensor assembly 90. In addition, the voltage sensor assembly 90 generates heat during charging and discharging, but the heat can be transmitted to the end plate 50, and heat dissipation of the voltage sensor assembly 90 that is weak against heat is promoted.

  As shown in FIG. 1, a thermistor T is selectively attached to the plurality of holders 20. In this embodiment, the thermistors T are attached to the outermost holder 20, that is, the attachment frame 38 of the holder 20 between the cell 10 and one end plate 50 and between the cell 10 and the other end plate 51, respectively. The lead wire 95 connected to is connected to the voltage sensor assembly 90, and the temperature of the battery module is measured.

  By the way, since a heat insulation layer is formed with the heat insulation member which consists of the holder 20 between the cell 10 and the end plates 50 and 51, the cell 10 adjacent to the end plates 50 and 50 with large thermal mass is the remaining cell 10. Compared to the above, it is possible to prevent overcooling, thereby preventing variation in deterioration of the cell 10 due to variation in temperature between the plurality of cells 10, thereby improving the performance and extending the life of the battery module. .

  In addition, since the heat insulating member made of the holder 20 is formed of a plate-like member, it is possible to suppress an increase in the parallel length of the plurality of cells 10 by narrowing the interval between the plurality of cells 10, Further, the heat insulation effect can be further enhanced by circulating the refrigerant through the cooling passage 24 provided in the heat insulation member 20.

  Further, the cells 10 can be held at a constant interval by the holder 20 and can be insulated from each other. Also, since the holder 20 and the heat insulating member 20 are the same, the number of parts can be reduced. In addition, the cell 10 and the pair of end plates 50 and 51 have substantially the same shape held portions 10A, 50A and 51A, and can be held by the heat insulating member 20 and the holder 20, which are the same. The structure is simplified and can be reliably held.

  Since the surfaces of the pair of end plates 50 and 51 facing the holder, that is, the heat insulating member 20 are formed in a lattice shape, the heat transfer area between the end plates 50 and 51 and the cell 10 is reduced, and the heat insulation between them is performed. The effect can be enhanced.

  A voltage sensor assembly 90 is arranged on the surface of the end plate 50 opposite to the surface facing the holder, that is, the heat insulating member 20, and the end plate 50 has a thermal conductivity and volume larger than those of the voltage sensor assembly 90. Since it is large, heat is generated from the voltage sensor assembly 90 that easily generates heat to the end plate 50 having a large thermal mass, and the voltage sensor assembly 90 can be prevented from overheating.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

10 .... cell 20 ..... holder (heat insulation member)
24 ··· Cooling passage 30 ··· Holding member 50 ··· End plate 51 ··· End plate 90 ··· Voltage sensor assembly

Claims (5)

A plurality of cells (10) stacked in parallel at intervals;
In the battery module comprising the pair of end plates (50, 51) for sandwiching the plurality of cells (10) from outside in the parallel direction thereof,
A battery module characterized in that a heat insulating member (20) for insulating between the cell (10) and the pair of end plates (50, 51) is interposed.   The heat insulating member (20) is constituted by a plate-like member, and in this plate-like member, a cooling passage (24) through which a refrigerant flows between the cell (10) and the pair of end plates (50, 51). The battery module according to claim 1, wherein the battery module is formed.   Between the plurality of cells (10), there is provided a holder (20) that keeps the distance between adjacent cells (10) constant, and this holder (20) is the same as the heat insulating member (20). The cell (10) and the pair of end plates (50, 51) are held parts having substantially the same shape that are held by the heat insulating member (20) and a holding member (30) provided in the holder (20). The battery module according to claim 1 or 2, wherein the battery module has (10A, 50A, 51A).   The battery module according to claim 3, wherein surfaces of the pair of end plates (50, 51) facing the heat insulating member (20) are formed in a lattice shape.   A voltage sensor assembly (90) is arranged on one surface of the pair of end plates (50, 51) opposite to the surface facing the heat insulating member (20), and the end plate (50 5. The battery module according to claim 3, wherein thermal conductivity and volume are formed larger than that of the voltage sensor assembly (90).

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