JP5537497B2 - Battery module - Google Patents

Description

  The present invention relates to a battery module.

  Conventionally, in order to increase load voltage and load capacity, a plurality of single cells (secondary batteries) are connected in series, in parallel, or a combination of them to form a battery pack and store it in a housing The modular structure is often taken.

  As such a battery module structure, a method in which a plurality of single cells are closely arranged and tightened and stored in a hard case is common. However, this alone does not dissipate the heat generated by the battery itself, accumulates it in the hard case, and the battery becomes hot, resulting in a short life.

  In recent years, applications used for rapid charging and high-rate discharge have increased, and the battery temperature tends to be high, which further shortens the lifetime. In particular, when an assembled battery is configured by stacking unit cells so that the wide surfaces of flat or flat unit cells are in contact with each other, there is almost no heat dissipation path other than tab leads, and the temperature of the unit cell located in the center in the stacking direction Becomes the highest and reaches the end of life earlier than the other unit cells, and as a result, the life of the battery module is shortened. For this reason, various module cooling methods have been proposed that make the cell temperature difference between the layers as uniform as possible.

  For example, Patent Document 1 describes that an interlayer member composed of a heat insulating member having heat insulating properties or a heat radiating member having good heat conductivity is sandwiched between stacked battery cells. Further, Patent Document 2 discloses a plurality of stacked batteries, an exterior member that extends in the stacking direction of the batteries and has thermal conductivity, a heat insulating portion, and an outer side connected to heat transfer portions on both sides of the heat insulating portion. And a spacer having an abutment surface portion, a technique in which the heat transfer portion abuts on the surface of the battery and the outer abutment surface portion abuts on the exterior member is described.

JP 2006-196230 A JP 2010-218716 A

  By the way, the patent document 1 describes a configuration in which an interlayer member having thermal conductivity between flat-plate batteries and a heat transfer member forming a module container are integrally formed by, for example, aluminum die casting. Yes. By such integral molding, there is no contact thermal resistance between the interlayer member and the module container, so that the thermal conductivity is good, the heat dissipation in the battery plane direction is good, and the temperature of each battery is made uniform. The

  In addition, in the case of a flat type battery, the heat conductive interlayer member is not only adhesive, but also ensures that an appropriate surface pressure is always applied to the battery through the interlayer member as well as the heat transfer performance. It is desirable from the aspect of performance and life. That is, it is desirable in terms of heat transfer and performance that an appropriate surface pressure is applied in the stacking direction for a long period of time in a flat battery pack aiming at a long life.

  However, in the battery module provided with the aluminum die-cast container (battery pack) of Patent Document 1, since the interlayer member is fixed in the container in advance, each battery is determined at the time of assembly. It is necessary to insert between them. At this time, each battery must be set not only by being inserted but also by an appropriate surface pressure setting. There is a problem that it is extremely difficult in assembly work to perform the insertion and the surface pressure adjustment work at the same time. Even if an appropriate surface pressure is applied after insertion, it is difficult to uniformly apply a desired surface pressure to the flat plate surface of the battery in the configuration in which the interlayer member is fixed to the container. In particular, when a large number of batteries are handled as the capacity of the module increases, problems remain in work efficiency or surface pressure management during assembly.

  In Patent Document 2, a spacer having a heat insulating material at the center and a heat conductive material on the outside is interposed between the batteries, and U-shaped members are welded to both ends of the spacer in a direction orthogonal to the stacking direction. A configuration is described in which a U-shaped member is fixed to a heat transfer portion of a housing by screws and a battery is accommodated between the U-shaped member and a spacer. Thereby, a uniform pressure is applied to the single cells sandwiched between the spacers, and heat generated in the cells can be efficiently radiated to the outside.

  However, with such a configuration, the structure and the assembling method become very complicated. That is, with respect to the assembling method, first, the spacer is temporarily fixed with screws to the bottom plate and the top plate forming the casing through the U-shaped member attached to the spacer. Thereafter, the battery is inserted between the spacers and pressed in the stacking direction with an appropriate surface pressure. Note that the bottom and top plate screw holes are elongated so that they can be moved to absorb the thickness variation in the stacking direction due to surface pressure, and after adjusting the surface pressure and position, the screws Tighten this.

  In addition, because the U-shaped member interposed between the heat conduction plate and the housing (exterior case) is connected to the heat conduction plate side by welding and screwed to the case side, especially with the increase in capacity of the module, When handling a large number of batteries, problems such as complicated assembly work including positioning of the heat conduction plate, an increase in the number of man-hours, and an increase in the cost due to an increase in the number of parts remain.

  Further, both Patent Document 1 and Patent Document 2 have a structure in which the heat conducting plate and the housing are completely fixed. However, among lithium ion batteries, a laminate type battery may have a property of expanding and contracting in the thickness direction during charging and discharging. It may also swell due to gas generation.

  In this case, the fact that the heat conducting plate and the casing are integrally formed or fixed with screws means that the gap between the heat conducting plates into which the laminate type batteries are inserted is always constant. Therefore, when the cell (single cell) expands, there is no allowance in the thickness direction, so that the internal pressure rises and the thermocompression seal portion on the side surface of the cell may be broken and gas or liquid may be ejected. Conversely, when the cell contracts, the surface pressure decreases, the contact thermal resistance between the heat conducting plate and the cell increases, and the battery performance is adversely affected.

  In order to prevent this, it is important to manage the surface pressure during assembly, but the heat conduction plate can follow the change in the thickness direction of the cell even during operation to prevent an extreme rise in the internal pressure of the cell. It is desirable to prevent breakage. On the other hand, even when the cell contracts, it is necessary from the viewpoint of heat conduction to maintain the contact between the cell plane and the heat conduction plate, that is, the surface pressure.

  The present invention provides a battery module that can make the temperature difference between single cells uniform, has excellent cooling capacity over a long period of time, is easy to assemble the module, and is excellent in cell surface pressure management even during battery operation. To do.

  The present invention provides a housing for stacking and housing a plurality of planar secondary batteries, a heat conductive plate provided between the stacked secondary batteries, having good thermal conductivity, and the heat conductive plate. An elastic body having good thermal conductivity provided at both ends of a pair or two pairs facing each other, and a groove portion on which the elastic body is supported is provided on the inner wall of the housing. The elastic body is in close contact with each other.

  According to the present invention, a battery module that can make the temperature difference between single cells uniform, has excellent cooling capacity for a long time, is easy to assemble a module, and has excellent cell surface pressure management even during battery operation. Structure can be provided.

It is a longitudinal cross-sectional view which shows the battery module which concerns on 1st Embodiment. It is a partially exploded perspective view which shows the component of the housing of the battery module which concerns on 1st Embodiment. It is a side view which shows the fixing method of the assembled battery which laminated | stacked the cell at the time of accommodating in the housing | casing of the battery module which concerns on 1st Embodiment. It is a perspective view which shows the heat conductive board and spring part of the battery module which concern on 1st Embodiment. It is sectional drawing which shows the support structure of the spring part to the housing of the battery module which concerns on 1st Embodiment. It is a longitudinal cross-sectional view which shows the internal state in driving | operation of the battery module which concerns on 1st Embodiment. It is sectional drawing which shows the modification of the support structure of the spring part to the housing of the battery module which concerns on 1st Embodiment. It is a longitudinal cross-sectional view which shows the battery module which concerns on 2nd Embodiment. It is sectional drawing which shows the support structure of the spring part to the housing of the battery module which concerns on 3rd Embodiment.

(First embodiment)
As shown in FIG. 1, the battery module 1 </ b> A according to the first embodiment includes a plurality of rectangular flat plate (flat plate or flat plate) laminate cells 2 (2 a to 2 g) (secondary battery), a heat conductive plate 20. 30A (elastic body, spring), buffer materials 40a and 40b, the laminate cell 2, the heat conduction plate 20, the spring portion 30A, and the housing 10 that houses the buffer materials 40a and 40b. Further, in the present embodiment, an example in which seven laminate cells 2 are laminated will be described as an example. However, the number is not limited to this number, and even when the number is less than seven, the number is larger than seven. It may be a configuration.

  The laminate cell 2 is, for example, a lithium ion secondary battery, and a laminate in which a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are laminated via a separator is formed in an electrolyte solution in a rectangular laminate film in plan view. It is housed and sealed together (none of which are shown). In addition, the laminate film is comprised with the metal laminate film which has a heat-fusion resin layer, and the outer peripheral edge part is sealed by heat-sealing.

  Although not shown, each laminate cell 2 has a positive electrode terminal portion and a negative electrode terminal portion drawn out from the edge of the laminate film, and each laminate cell 2 is electrically connected in series. The positive electrode terminal portion and the negative electrode terminal portion described above are from the front side (front side in the drawing) or the back side (back side in the drawing) of FIG. 1, that is, from the edge portion (side portion) where the spring portion 30A described later is not provided. When pulled out, it is preferable in terms of workability and space.

  The casing 10 is a metal case having a square box shape (see FIG. 2), and a top plate 11 that covers the upper side, a bottom plate 12 that covers the lower side, a side plate 13 that covers the side, 13, 14, 14.

  As shown in FIG. 2, the inner wall 13s of the side plates 13 and 13 is formed with a groove 13A extending in the Y direction (second direction) orthogonal to the stacking direction of the laminate cells 2 (hereinafter referred to as Z direction), Six grooves 13A are formed at intervals in the Z direction. The groove 13A is formed at a position facing the heat conductive plate 20 between the laminate cells 2 (see FIG. 1).

  As a method for fixing the bottom plate 12 and the side plate 13 and a method for fixing the top plate 11 and the side plate 13, methods such as screwing and welding can be employed. Incidentally, the side plates 13 and 13 are fixed to the bottom plate 12, the buffer material 40b and the assembled battery 2A (see FIG. 3) described later are accommodated, the buffer material 40a is stacked, and the top plate 11 is the upper edge portion 13t of the side plate 13. Connected and fixed at Then, the side plate 14 (rear plate: rear side in the figure) is connected and fixed to the top plate 11, the bottom plate 12, and the side plates 13, 13, and finally the side plate 14 (front front plate: front side in the figure) is connected and fixed. As a result, the battery module 1A (see FIG. 1) is assembled.

  As shown in FIG. 3, when each laminate cell 2 (2 a to 2 g) is accommodated in the housing 10, an assembled battery 2 </ b> A formed by laminating the laminate cell 2 and the heat conductive plate 20 is used as each laminate cell 2. Fixing jigs 3 and 3 are used for fixing so as not to slip.

  The fixing jig 3 is composed of an insulating band or an insulating tape that covers the entire circumference of the assembled battery 2A. The fixing jig 3 is removed after being incorporated into the housing 10. Although it is possible to assemble the battery module 1A without using such a fixing jig 3, the assembling workability deteriorates.

  Returning to FIG. 1, the heat conductive plate 20 is composed of, for example, a plate having a rectangular shape made of metal such as copper or aluminum alloy having high heat conductivity (good heat conductivity). It has the upper surface 20a and the lower surface 20b which oppose, and is pinched | interposed between the laminate cells 2 (2a-2g). Moreover, the upper surface 20a and the lower surface 20b of the heat conductive plate 20 have the area which the whole surface orthogonal to the Z direction of the laminate cell 2 (2a-2g) can contact.

  The spring portion 30 </ b> A is formed to project from the end portion 20 c of each heat conducting plate 20 toward the side plate 13, and a tip portion thereof is inserted into a groove portion 13 </ b> A formed on the side plate 13, so that the spring portion 30 </ b> A is supported by the housing 10. It is configured to be.

  As shown in FIG. 4, the spring portion 30A expands and contracts in the X direction (first direction) perpendicular to the Z direction (stacking direction) and expands and contracts in the Z direction (stacking direction). And a flat plate portion 30b having a surface parallel to the Z direction (stacking direction).

  In the present embodiment, the spring portion 30A (the expansion / contraction bending portion 30a and the flat plate portion 30b) is formed of a metal plate having high thermal conductivity such as copper or aluminum alloy in the same manner as the thermal conduction plate 20, and is thermally conductive. The structure is integrated with the plate 20. Further, in the present embodiment, the case where the plate thickness of the spring portion 30A and the plate thickness of the heat conducting plate 20 are different from each other is described as an example, but the present invention is not limited to this, and each plate is not limited thereto. The thickness may be the same. Note that the plate thickness of the spring portion 30A may be determined according to the appropriate elastic force required for the spring portion 30A.

  The expansion / contraction bending part 30a has a corrugated shape extending in the X direction while being folded back in the Z direction. Moreover, the dimension of the expansion / contraction bending part 30a in the Y direction (depth direction) is the same as the dimension d of the heat conduction plate 20 in the Y direction (depth direction).

  The flat plate part 30b is located at the tip of the expansion / contraction bending part 30a, has a rectangular plane 30b1 constituted by the Z direction and the Y direction, and is formed integrally with the expansion / contraction bending part 30a. Moreover, the dimension of the Y direction (depth direction) of the flat plate part 30b is formed the same as the dimension d of the Y direction of the heat conductive board 20 and the expansion-contraction bending part 30a. Further, the dimension H1 in the Z direction of the flat plate portion 30b can be inserted into the groove 13A, and is formed to be larger than the dimension H2 in the Z direction of the expansion / contraction bending part 30a. The dimension H2 is set so that the expansion / contraction bending part 30a does not contact the groove 13A even if the expansion / contraction bending part 30a is bent in the Z direction at the maximum.

  The buffer material 40a (see FIG. 1) is provided so as to be sandwiched between the laminate cell 2 (2a) located at the uppermost stage and the top plate 11. Similarly, the buffer material 40b (see FIG. 1) is provided so as to be sandwiched between the laminate cell 2 (2g) located at the lowermost stage and the bottom plate 12. In addition, as the buffer materials 40a and 40b, elastic materials such as urethane and rubber are used.

  The thickness H3 (see FIG. 1) of the buffer materials 40a and 40b is designed to have a thickness adjusted in advance so that the surface pressure applied to each laminate cell 2 of the assembled battery 2A becomes an appropriate pressure. Appropriate pressure means that the adhesiveness between the heat conductive plate 20 and the laminate cell 2 is well maintained with respect to expansion and contraction (expansion and contraction) in the thickness direction (Z direction) of the laminate cell 2 during operation, and The surface pressure that can suppress the increase in internal pressure by following the expansion of the laminate cell 2 to such an extent that the thermocompression-bonding seal portion of the laminate film is not broken by the increase in the internal pressure of the laminate cell 2.

  As shown in FIG. 5, the heat conductive plate 20 has spring portions 30A at both ends 20c in the X direction (one is not shown). The heat conductive plate 20 is sandwiched between the laminate cell 2a (2) and the laminate cell 2b (2), and the lower surface of the laminate cell 2a is connected to the upper surface 20a of the heat conductive plate 20 and the laminate cell 2b. The upper surface is in close contact with and in contact with the lower surface 20b of the heat conducting plate 20.

  On the other hand, the spring portion 30 </ b> A is integrally formed with the heat conductive plate 20 that protrudes from the laminate cell 2 in the X direction. Further, the spring portion 30A has its tip portion inserted into the groove portion 13A, and the flat surface 30b1 (entire surface) of the flat plate portion 30b is in contact with and in contact with the vertical surface 13a (inner wall surface) within the groove portion 13A. .

  As described above, the flat plate portion 30b is in contact with the vertical surface 13a of the groove portion 13A, but the pressing force P is applied to the vertical surface 13a by the flat surface 30b1 of the flat plate portion 30b by the elastic action of the spring portion 30A. Yes. This pressing pressure P is determined by the length Lb of the spring portion 30A (expandable flexure portion 30a) based on the elastic characteristics of the spring, and when assembling the battery module 1A, the two side plates 13, 13 facing each other shown in FIG. Is determined by the distance W (see FIG. 2). That is, when the battery module 1A is assembled, the spring length Lb is also determined by determining the positions of the side plates 13 and 13.

  Further, by forming the groove portion 13A in the inner wall 13s of the side plate 13, the spring portion 30A can be firmly supported in the housing 10. The groove 13A also serves as a guide when the assembled battery 2A is installed on the side plate 13. That is, when a load is applied to the assembled battery 2A (see FIGS. 1 and 3) sandwiched between the two side plates 13 and 13 from the side surface, the respective heat conduction plates 20 are horizontally displaced without causing a positional shift. Sex is maintained. As a result, an equal load is applied from each heat conduction plate 20 to the spring portion 30A.

  When the battery module 1 </ b> A is assembled, the spring portion 30 </ b> A of the assembled battery 2 </ b> A is fitted into the groove portion 13 </ b> A of the one side plate 13. Similarly, after the flat plate portion 30b of the spring portion 30A is fitted into the groove portion 13A in the other side plate 13, the distance W between the side plates 13 set for adjusting the pressing pressure P (see FIG. 2) is set. Both side plates 13, 13 are fixed to the bottom plate 12.

  Further, by having the spring portion 30A, even if a positional shift occurs between the groove portion 13A and the flat plate portion 30b in the manner of fixing the assembled battery 2A by the fixing jig 3 shown in FIG. Since the deviation can be absorbed by the bending deformation, the mounting work of the assembled battery 2A in the housing 10 becomes easy.

  Incidentally, when the top plate 11 is fixed, the fixing jig 3 (see FIG. 3) becomes unnecessary and is removed. Thereafter, the side plate 14 (rear plate) is attached, and finally the side plate 14 (front front plate) is attached, and the assembly of the battery module 1A is completed.

  Next, a heat transfer path of heat generated in the laminate cell 2 in the battery module 1A will be described with reference to FIG. This heat transfer path is roughly divided into a first transfer path and a second transfer path.

  First, for the first heat transfer path, for example, heat generated in the laminate cell 2c (2) passes through the contact surfaces S1, S2 between the heat conductive plates 20A (20), 20B (20) and the laminate cell 2c. It is transmitted to the conductive plates 20A and 20B. The heat transmitted to the heat conductive plates 20A and 20B is transmitted from the expansion / contraction bending portion 30a of the spring portion 30A to the flat plate portion 30b. Then, heat is transferred to the outer surface of the side plate 13 of the housing 10 through the vertical surface 13a (inner wall surface) of the groove 13A formed in the side plate 13 of the housing 10 that contacts the flat plate portion 30b of the spring portion 30A. . The heat transmitted to the outer surface of the side plate 13 is radiated by cooling of forced convection heat transfer or natural convection heat transfer by a refrigerant (not shown).

  In the present embodiment, the case where the heat of the laminate cell 2 flows in the X direction, that is, the case where the pair of opposite end portions 20c, 20c of the heat conducting plate 20 have the spring portions 30A, 30A will be described as an example. However, there is an additional path for transferring heat of the laminate cell 2 in the direction orthogonal to the X direction (Y direction), that is, the spring portions 30A at the two opposing ends of the heat conduction plate 20. Similarly, the heat of the laminate cell 2 is transmitted to the side plate (rear plate) 14 of the housing 10 through the heat conductive plate 20 and the spring portion. The actions and effects at this time are the same as in the X direction.

  The second heat transfer path is a path in the laminating direction (Z direction) of the laminate cell 2, and for example, the heat generated in the laminate cell 2c is changed in the thickness direction of each laminated cell 2 and each heat conduction plate 20 ( This is a heat transfer path that flows toward the top plate 11 and the bottom plate 12 of the housing 10 while being transmitted in the Z direction).

  By the way, if only the cooling effect of the entire assembled battery 2A is to be improved, it is sufficient to devise measures to increase the thermal conductivity of the path in both the first heat transfer path and the second heat transfer path. However, in order to keep the temperature difference between the laminate cells 2 as uniform as possible at the same time as the cooling effect, it is desirable that heat flow through the first heat transfer path rather than the second heat transfer path.

  Generally, the temperature distribution of the assembled battery 2A is the highest in the laminate cell 2d located in the center in the stacking direction (Z direction), and the temperature decreases as the distance from the center in the stacking direction increases. 2g shows the tendency to become the lowest. For this reason, the temperature distribution (temperature difference) of the assembled battery 2A becomes more conspicuous as the ratio of the heat transfer amount flowing through the second heat transfer path becomes larger than the first heat transfer path to the side plate 13.

  That is, the temperature difference of the laminate cell 2 increases in proportion to the ratio of the heat transfer amount flowing in the second heat transfer path. When the temperatures of the respective laminate cells 2 are different, particularly when the laminate cells 2 are electrically connected in series, the difference in charge / discharge characteristics and deterioration rate is likely to increase when viewed over a long period of time. As a result, for example, the entire battery module 1A is affected by the laminate cell 2d having a high deterioration rate, which is disadvantageous in terms of extending the life.

  Therefore, in the present embodiment, a structure having excellent heat conductivity in the X direction (first heat transfer path) is adopted by providing the heat conductive plate 20 between the laminate cells 2. Such a structure makes it possible to make uniform the temperature distribution of each laminate cell 2 itself in contact with the heat conductive plate 20. However, unless the heat is finally effectively transferred to the side plate 13 side of the housing 10, the cooling effect of the laminate cell 2 is reduced and the temperature is increased. Moreover, the ratio of the heat transfer amount of the second heat transfer path is relatively increased, and the temperature difference between the laminate cells 2 cannot be reduced.

  Therefore, in the present embodiment, the heat conduction plate 20 is further provided with the spring portion 30A, and the flat plate portion 30b is always the vertical surface 13a of the groove portion 13A of the housing 10 by the elastic action of the expansion / contraction bending portion 30a of the spring portion 30A. Can be brought into close contact with a certain pressure (pressing pressure P). As a result, it is possible to reduce the contact thermal resistance between the flat plate portion 30b and the vertical surface 13a as compared with the case where the pressing pressure P is simply zero. Therefore, the heat conduction performance to the side plate 13 can be improved by reducing the thermal resistance between the spring portion 30A and the vertical surface 13a, which is the most heat-conductive and rate-limiting (neck) in the first heat transfer path.

  In addition, with respect to the second heat transfer path, the buffer material 40a is laminated between the top plate 11 and the laminate cell 2a. Similarly, a buffer material 40b is laminated between the bottom plate 12 and the laminate cell 2g. The buffer materials 40a and 40b have low thermal conductivity as one of the functions. Since the heat resistance toward the top plate 11 and the bottom plate 12 is increased by stacking the buffer materials 40a and 40b at the positions described above, the heat transfer amount is relatively small compared to the heat transfer amount from the first heat transfer path. It becomes possible to do.

  From the above, according to the present embodiment, the ratio of the heat transfer amount from the first heat transfer path can be made larger than the ratio of the heat transfer amount from the second heat transfer path. It becomes possible to make the temperature difference more uniform. In order to further enhance the cooling effect and the temperature equalizing effect, a housing provided with a heat sink (not shown) on the outer surface of the side plate 13 may be used.

  By the way, the laminate cell 2 has a structure in which a thin aluminum plate is simply covered with a laminate resin as an exterior portion for containing and sealing a sheet-like positive electrode, a sheet-like negative electrode, and a separator. For this reason, the laminate cell 2 is weak in strength, and the laminate cell 2 expands and contracts in the thickness direction (Z direction) during charge and discharge, and the exterior portion is also deformed accordingly.

  FIG. 6 is a longitudinal sectional view showing an internal state during operation of the battery module according to the first embodiment. That is, FIG. 6 shows a state of the battery module 1A when the laminate cell 2 expands in the thickness direction (Z direction). Thus, when the thickness Ls of each laminate cell 2 increases, the overall height H of the assembled battery 2A also increases. At this time, the buffer material 40a, 40b contracts in the thickness direction (Z direction), so that the difference in elongation (elongation allowance) of the assembled battery 2A can be absorbed, and an appropriate surface pressure is maintained for each laminate cell 2. Will be.

  If this difference in elongation (elongation allowance) cannot be absorbed, the internal pressure of the laminate cell 2 is increased, and the thermocompression seal portion of the laminate cell 2 may be broken. In this embodiment, the buffer material 40a, By providing 40b, the elastic action of the buffer materials 40a and 40b serves to prevent this. On the other hand, when the laminate cell 2 contracts, the buffer materials 40 a and 40 b expand in reverse, and an appropriate surface pressure is maintained for each laminate cell 2.

  Further, for example, when the laminate cell 2 expands, the interval between the heat conductive plate 20 and the heat conductive plate 20 must naturally be widened. For example, the heat conduction plate 20A (20) on the upper side of the laminate cell 2d positioned in the center in the stacking direction is lifted by Δd1 from the position before expansion, but in the laminate cell 2b, each laminate cell 2d, Since the elongation difference (elongation allowance) of 2c is added, the heat conduction plate 20C (20) is lifted by Δd2 larger than Δd1. With respect to the displacement of the heat conductive plates 20 due to the expansion of the laminate cell 2, for example, the spring portion 30A of the heat conductive plate 20C is bent upward in the Z direction by an angle α.

  On the other hand, the same applies to the lower side of the central laminate cell 2d. For example, in the heat conductive plate 20E (20) positioned below the laminate cell 2f, the spring portion 30A is bent downward by an angle α. In addition, since the amount of bending of the spring portion 30A (expandable bending portion 30a) increases from the central laminate cell 2d in the stacking direction (Z direction), the angle of bending also increases. Each spring portion 30A is configured to have an elastic characteristic capable of following these deformations.

  Thus, due to the stretchability of the buffer materials 40a and 40b and the elastic action of the spring portion 30A, an appropriate surface pressure is maintained in the lamination direction of each laminate cell 2 even if the thickness of the laminate cell 2 changes. . In addition, the pressing force P (see FIG. 5) to the vertical surface 13a of the side plate 13 is also maintained by the expansion / contraction action in the X direction of the spring portion 30A (expansion / contraction bending portion 30a). The heat conducts to the side plate 13 through the heat conduction plate 20 and the spring portion 30A, and the heat conductivity is kept good.

  As described above, in the battery module 1 </ b> A according to the first embodiment, the heat conductive plate 20 having good thermal conductivity provided between the laminate cells 2 and the pair of opposite ends 20 c and 20 c of the heat conductive plate 20. And a spring portion 30A (elastic body) provided on the inner wall 13s of the housing 10. A groove portion 13A for supporting the spring portion 30A is formed on the inner wall 13s of the housing 10, and the spring portion 30A is in close contact with the groove portion 13A. Is. According to this, the heat from each laminate cell 2 is transferred to the groove portion 13A of the housing 10 through the heat conductive plate 20 in contact with each laminate cell 2 and the spring portion 30A (elastic body) to dissipate heat. Can do. In addition, since the spring portion 30A can always be in close contact with the groove portion 13A with a certain pressure (pressing pressure P) due to the elastic action of the spring portion 30A, compared to the case where the pressing pressure P is simply in contact with zero, The contact thermal resistance between the spring portion 30A and the groove portion 13A can be reduced, and the spring portion 30A and the groove portion 13A that are the most heat-conductive and rate-limiting (neck) in the heat transfer path from the heat conductive plate 20 to the groove portion 13A The heat resistance between the side plates 13 can be improved. Further, due to the elastic action of the spring portion 30A, an appropriate surface pressure is maintained in the lamination direction of each laminate cell 2 even if the thickness of the laminate cell 2 changes, and in addition, in the X direction of the spring portion 30A. Since the pressing force P to the groove portion 13A is also maintained by the expansion and contraction action of the heat, the heat generated from the laminate cell 2 passes through the heat conduction plate 20 and the spring portion 30A, and the heat conduction performance to the groove portion 13A is kept good. . Therefore, the temperature difference between the laminate cells 2 can be made uniform, the cooling capacity is excellent for a long time, and the surface pressure management of the laminate cells 2 is excellent even during the operation of the battery module 1A. Further, as described above, the battery module 1A can be easily assembled.

  In the first embodiment, the flat plate portion 30b is formed at the tip of the spring portion 30A, and the entire surface (plane 30b1) of the flat plate portion 30b and the vertical surface 13a (inner wall surface) of the groove 13A are configured to be in close contact with each other. The spring portion 30A and the heat conducting plate 20 have good heat conductivity and are integrated. According to this, since the heat transfer area can be secured widely by bringing the flat plate portion 30b and the vertical surface 13a into contact with each other, the heat of the laminate cell 2 is transferred from the spring portion 30A to the housing 10. The heat conduction performance can be further improved. Further, by integrating the spring portion 30A and the heat conducting plate 20 with a material having good heat conductivity, the contact thermal resistance between the spring portion 30A and the heat conducting plate 20 can be eliminated (or reduced). Therefore, the thermal conductivity becomes good and the uniformity of the temperature difference between the respective laminate cells 2 can be improved.

  In the first embodiment, the spring portion 30A is configured to expand and contract in the first direction (X direction) orthogonal to the lamination direction (Z direction) of the laminate cell 2 and bend in the lamination direction (Z direction). The flat plate portion 30b has a surface extending in the stacking direction. According to this, the horizontality is maintained without causing the respective heat conduction plates 20 to be displaced and inclined, and an equal load can be applied from each heat conduction plate 20 to the spring portion 30A. Further, since the flat plate portion 30b has a surface (plane 30b1) extending in the stacking direction (Z direction), the flat plate portion 30b and the groove portion 13A are always stabilized by the spring portion 30A that expands and contracts in the first direction (X direction). In addition, even if the laminate cell 2 expands and contracts and the spring portion 30A is bent in the stacking direction, the flat plate portion 30b and the groove portion 13A can be reliably adhered.

  Further, in the first embodiment, the groove portion 13A is provided on two opposing surfaces of the four side surfaces provided in the stacking direction of the laminate cell 2 in the casing 10, and the number of the heat conductive plates 20 is the stacking direction. It extends in a second direction (Y direction) perpendicular to each other. According to this, it becomes possible to support each heat conductive board 20 firmly by the spring part 30A being supported by the groove part 13A.

  In the first embodiment, the flat plate portion 30b is in contact with the vertical surface 13a (inner wall surface) extending in the stacking direction of the groove portions 13A. According to this, the elastic force of the spring portion 30A can be received stably, and the adhesion between the flat plate portion 30b and the vertical surface 13a can be enhanced.

FIG. 7 is a cross-sectional view showing a modification of the structure for supporting the spring portion to the housing of the battery module according to the first embodiment.
A battery module 1A according to this modification is obtained by modifying the structure of the groove 13A. In FIG. 7, only the groove portion 13A into which the spring portion 30A on one end side of one heat conducting plate 20 is inserted is illustrated, but the groove portion into which the spring portion on the other end is inserted is disposed at other positions. The groove portions to be formed are assumed to be formed in the same manner, and the description thereof is omitted.

  The groove portion 13A is formed on the inner wall 13s of the side plate 13 and has a substantially T shape in cross section. The groove 13b into which the spring portion 30A is inserted and a part (upper end portion and lower end portion) of the flat plate portion 30b are inserted. It consists of grooves 13c and 13c.

  The groove 13b has a vertical surface 13b1 (inner wall surface) with which the flat plate portion 30b abuts and horizontal surfaces 13b2 and 13b3 on which a part of the expansion / contraction bending portion 30a is disposed.

  The grooves 13c and 13c are respectively formed on the back side (the left end in the drawing) of the groove 13b. One (upper) groove 13c is formed so as to protrude upward in the horizontal plane 13b2, and the other (lower) groove 13c is formed so as to protrude downward in the horizontal plane 13b3.

  Further, the vertical surface 13b1 of the groove 13b and the vertical surface 13c1 constituting one side surface of each groove 13c are formed to extend linearly in the Z direction so as to be on the same plane. Thereby, the flat surfaces 30b of the spring portion 30A are configured to come into contact with each other on the vertical surfaces 13b1, 13c1, 13c1 (inner wall surfaces).

  Further, a push spring portion 30c is provided in the grooves 13c and 13c. The pressing spring portion 30c is constituted by a disc spring, and is provided on the other side surface 13c2 of each groove 13c. Thereby, the flat surface 30b1 of the front-end | tip of the flat plate part 30b is pressed by the urging | biasing force of the pressing spring part 30c, and the flat plate part 30b is pressed by the vertical surface 13b1, 13c1, 13c1 side. The pressing spring portion 30c is not limited to a disc spring, and may be another type of spring material such as a coil spring.

  According to such a modification, even if the heat conductive plate 20 moves up and down and the spring portion 30A bends in the vertical direction as compared with the structure shown in FIG. 5, the pressing pressure by the pressing spring portions 30c and 30c. Due to the effect, the flat plate portion 30b is always in close contact with the vertical surfaces 13b1, 13c1, and 13c1, so that the contact thermal resistance can be lowered. As a result, it is possible to maintain high thermal conductivity even with respect to the expansion / contraction change of the laminate cell 2, uniform temperature difference between the laminate cells 2 over a long period of time, and exhibit high cooling ability.

(Second Embodiment)
FIG. 8 is a longitudinal sectional view showing the battery module according to the second embodiment. In addition, about 2nd Embodiment, about the structure and effect similar to 1 A of battery modules which concern on 1st Embodiment, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The battery module 1 </ b> B has a structure in which a group of spring portions 30 </ b> B (expandable bending portions) at one end (the other end) of each heat conducting plate 20 is integrated by a single flat plate portion 30 t. That is, the battery module 1B includes spring portions 30B at both end portions 20c and 20c in the X direction of each heat conducting plate 20 inserted between the laminated cells 2 (2a to 2g) that are stacked. Each spring portion 30B on one end side in the X direction is connected to one flat plate portion 30t extending from one end (upper end) to the other end (lower end) in the stacking direction (Z direction). Similarly, each spring part 30B on the other end side in the X direction is also connected to the flat plate part 30t.

  The flat plate portion 30t is formed of a material having good thermal conductivity such as an aluminum alloy or copper, and is integrated with the spring portion 30B by welding or the like. The flat plate portion 30t is configured to be accommodated in a groove portion 13B provided on the inner wall 13s of the side plate 13 of the housing 10. The flat plate portion 30t is in close contact with and in close contact with the vertical surface 13d (inner wall surface) of the side plate 13 of the housing 10 by the elastic action of each spring portion 30B.

  According to the second embodiment, compared to the structure of the battery module 1A of the first embodiment, the area of the flat plate portion 30t that contacts the inner wall 13s of the side plate 13 of the housing 10 is increased, so that the heat transfer area is increased. And the thermal conductivity in the X direction can be increased. Further, since the heat transfer area increases, a method of fixing the flat plate portion 30t and the side plate 13 by screwing or the like can be easily adopted, and in addition to the pressing effect by the spring portion 30B, the contact resistance can be further reduced. Heat transfer performance is improved, and further temperature uniformity and temperature rise can be suppressed.

  Further, according to the second embodiment, as described in the first embodiment, when the assembled battery 2A is set in the housing 10, it is not necessary to insert the assembled battery 2A in accordance with the plurality of grooves 13A. Since only one flat plate 30t needs to be inserted into one groove 13B, the assembly workability is also improved.

(Third embodiment)
FIG. 9 is a cross-sectional view showing a support structure of a spring portion to the housing of the battery module according to the third embodiment. In FIG. 9, only the groove portion 13C into which the spring portions 31C and 32C at one end of one heat conducting plate 21 are inserted is illustrated, but the groove portion into which the spring portion at the other end is inserted, and at other positions. It is assumed that the grooves to be arranged are formed in the same manner, and the description thereof is omitted. Moreover, the overlapping description is abbreviate | omitted about the structure and effect similar to 1st Embodiment.

  The battery module 1C includes a heat conductive plate 21, spring portions 31C and 32C, and a groove portion 13C. About another structure, it is the same as that of 1st Embodiment.

  The groove portion 13C is formed on the inner wall 13s of the side plate 13 of the housing 10, and is configured such that the end portion of the heat conducting plate 21 is inserted into the groove portion 13C. In the present embodiment, the end of the heat conducting plate 21 is not in contact with the vertical surface 13c1 having a surface parallel to the Z direction of the groove 13C. The heat conductive plate 21 and the groove 13C may be in contact with each other within a range that does not interfere with the above.

  The spring portion 31C is inserted between the heat conductive plate 21 and the upper surface (one side surface) 13c3 of the groove portion 13C, and the spring portion 32C is interposed between the heat conductive plate 21 and the lower surface (the other side surface) 13c4 of the groove portion 13C. Has been inserted. The spring portions 31C and 32C are formed of a member having good thermal conductivity such as copper or an aluminum alloy, and have a function of expanding and contracting in the stacking direction (Z direction) of the laminate cell 2. .

  Moreover, as for spring part 31C, 32C, each edge part 30d, 30e is each exhibiting flat plate shape. One end 30d of the spring portion 31C is in contact with the upper surface 20a of the heat conducting plate 21, and the other end 30e is in contact with the upper surface 13c3 of the groove 13C. The spring portion 32C has one end 30d in contact with the lower surface 20b of the heat conducting plate 20C and the other end 30e in contact with the lower surface 13c4 of the groove 13C.

  As a result, the spring portion 31C is in close contact with the upper surface 20a of the heat conducting plate 21 and the upper surface 13c3 of the groove portion 13C while being pressed by the elastic action of the spring portion 31C in the stacking direction. The spring portion 32C is in close contact with and in close contact with the lower surface 20b of the heat conducting plate 21 and the lower surface 13c4 of the groove 13C while applying a pressing force by the elastic action in the stacking direction.

  The spring portions 31C and 32C may be physically independent from the side plate 13 and the heat conduction plate 21, or may be fixed to the upper surface 13c3 and the lower surface 13c4 in the groove portion 13C, respectively, and heat conduction. The plate 21 may be fixed to the upper surface 20a and the lower surface 20b of both ends.

  In such a battery module 1C, the heat generated in the laminate cell 2 flows in the X1 direction through the heat conductive plate 21, and is transmitted from the upper surface 20a and the lower surface 20b of the end portion of the heat conductive plate 21 to the spring portions 31C and 32C. Heat flows through the spring portions 31C and 32C and flows to the outer surface of the side plate 13 through the upper surface 13c3 of the groove portion 13C and the lower surface 13c4 of the groove portion 13C.

  According to the third embodiment, the contact thermal resistance component of both end portions 30d and 30e of the spring portions 31C and 32C existing in the heat transfer path from the heat conductive plate 21 to the side plate 13 of the housing 10 is the effect of the pressing pressure by the spring. Therefore, high thermal conductivity can be maintained.

  In addition, according to the third embodiment, the thermal conductive plate 21 in contact with the laminate cell 2 due to the elastic action of the spring portions 31C and 32C also in the expansion / contraction direction of the laminate cell 2 against the expansion and contraction of the laminate cell 2 described above. Can move. Therefore, an appropriate surface pressure is maintained in the lamination direction (Z direction) of each laminate cell 2.

  Since the amount of change in displacement of the heat conducting plate 21 increases from the center laminate cell 2 of the assembled battery 2A in the stacking direction, the height H4 from the heat conducting plate 21 to the upper surface 13c3 of the groove 13C and the spring You may make it the structure which enlarges the expansion-contraction length of 31 C as it goes to the lamination direction from the said center.

  Incidentally, in the third embodiment, unlike the structure of the battery module 1A of the first embodiment, the contact surfaces of the heat conducting plates 21 of both end portions 30d and 30e of the spring portions 31C and 32C and the upper surface 13c3 and the lower surface 13c4 of the groove portion 13C. Therefore, even if the heat conduction plate 21 moves during expansion / contraction of the laminate cell 2, the contact surface is displaced or the end portions 30d of the spring portions 31C and 32C are moved. , 30e does not float and the contact area does not change, so that better and more favorable thermal conductivity is maintained.

  The arrangement of the spring portions 31C and 32C provided on the heat conduction plate 21 is such that the groove portions 13A, 13B and 13C are provided on the two surfaces of the side plates 13 and 13 of the housing 10 as seen in each of the embodiments described above. However, the present invention is not limited to this, and it is possible to provide grooves on the four surfaces of the side plates 13, 13, 14, and 14. As a result, the heat transfer path from the heat conductive plate 21 to the side plate 13 increases, so that the heat transfer property is further increased and the temperature equalizing effect is further increased.

  In addition to the uniform temperature and cooling effects, as a common effect for the above-described embodiments, the spring portions 30A, 30B, 31C, and 32C are incorporated into the structure of the battery modules 1A, 1B, and 1C, and the spring portion 30A. , 30B, 31C, 32C, each laminate cell 2 is supported, so that the impact force can be reduced even when an impact is applied to the battery modules 1A, 1B, 1C. As a result, the reliability of the battery modules 1A, 1B, 1C is also improved.

  Further, the first embodiment is performed between the upper surface of the laminate cell 2a (2) located at the uppermost stage and the buffer material 40a, and between the lower surface of the laminate cell 2g (2) located at the lowermost stage and the buffer material 40b. You may add the structure which consists of the heat conductive board 20, the spring part 30A, and the groove part 13A in a form (2nd Embodiment and 3rd Embodiment may be applied). Thereby, it can pinch with the heat conductive board 20 from the upper and lower sides with respect to all the lamination cells 2 (2a-2g), and can further improve equalization of the temperature difference between all the lamination cells 2. FIG.

  In the present embodiment, the spring portions 30A, 30B, and 30C have been described by taking an example in which a metal plate is bent into a corrugated shape. However, for example, a plurality of coil springs are arranged in the Y direction, and the tips of the coil springs ( A configuration in which a flat plate portion having a surface parallel to the laminating direction may be attached to a portion facing the vertical surface 13a of the groove portion 13A at one end).

  In addition, although embodiment which concerns on this invention gave and demonstrated the case where the laminated cell was made into the object as an example, it was not limited to a laminated cell and the electrode etc. were accommodated in the thin metal can. The present invention can also be applied to single cells and has the same functions and effects as those of the present embodiment. Furthermore, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Further, the configuration of another embodiment can be added to the configuration of a certain embodiment.

1A, 1B, 1C Battery module 2 (2a, 2b, 2c, 2d, 2e, 2f, 2g) Laminate cell (secondary battery)
10 Housing 13, 14 Side plate 13A, 13B, 13C Groove 13a, 13b1, 13c1, 13d Vertical surface (inner wall surface)
13c3 Upper surface 13c4 Lower surface 13s Inner wall 20, 21 Thermal conduction plate 20a Upper surface 20b Lower surface 30A, 30B, 31C, 32C Spring portion (elastic body, spring)
30a Telescopic bending part 30b, 30t Flat plate part 40a, 40b Buffer material

Claims (8)

A housing that houses a plurality of flat-plate-shaped secondary batteries stacked;
A heat conduction plate provided between the secondary batteries to be laminated and having good thermal conductivity;
An elastic body having good thermal conductivity provided at one or two opposite ends of the heat conducting plate;
The inner wall of the housing is provided with a groove portion that supports the elastic body,
The battery module, wherein the elastic body is in close contact with the groove. The elastic body is a spring having a flat plate portion at a tip portion;
The spring is located at both ends of the heat conducting plate, and is configured such that the entire surface of the flat plate portion and the inner wall surface of the groove portion are in close contact with each other,
The battery module according to claim 1, wherein the spring and the heat conducting plate have good heat conductivity and have an integrated structure. The spring is configured to expand and contract in a first direction orthogonal to the stacking direction of the secondary battery and bend in the stacking direction,
The battery module according to claim 2, wherein the flat plate portion has a surface extending in the stacking direction.   The groove portion is provided on the two opposing surfaces of the four side plates provided in the stacking direction of the secondary battery in the housing, or on the inner wall of the four surfaces, and the number of the heat conduction plates is the same as the stacking direction. 4. The battery module according to claim 2, wherein the battery module is formed to extend in a second direction orthogonal to each other, or in the second direction and the first direction. 5.   The battery module according to claim 4, wherein the flat plate portion is in contact with an inner wall surface of the groove portion extending in the stacking direction. The elastic body is a spring that expands and contracts in the stacking direction,
Both ends of the heat conducting plate are inserted into the groove,
The said spring is each inserted between the upper surface and lower surface of the said groove part which opposes the said lamination direction of the said heat conductive board in the vicinity of the both ends of the said heat conductive board. Battery module. Both ends of the spring have a flat plate shape,
One tip is in close contact with the upper and lower surfaces of the heat conducting plate and the other tip is in close contact with the upper and lower surfaces perpendicular to the stacking direction formed in the groove. The battery module according to claim 6. The flat plate portion is a single flat plate shape extending from one end to the other end in the stacking direction of the secondary battery,
4. The battery module according to claim 2, wherein the spring is connected to the flat plate portion in a number corresponding to the heat conductive plate.

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