JP2014191950A - Secondary battery module and secondary battery system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery module composed of secondary battery cells connected in plurality, in which each of the incorporated cells is efficiently cooled, and the incorporated cells can be easily and individually replaced.SOLUTION: The secondary battery module comprises a plurality of secondary battery cells connected to each other, a plurality of heat storage members for cooling the cells individually in contact therewith, a cell rack for accommodating the cells and the heat storage members. The cell rack has a trapezoidal comb tooth part whose upper base is shorter than the lower base. The heat storage members have a wedge-shaped container provided with a heat storage material therein, the wedge-shaped container being such that only one of the surfaces is an inclined surface, the inclination of which is the same as the inclination of a trapezoidal slope of the comb tooth part of the cell rack. The heat storage member is disposed so that the inclined surface adjoins the trapezoidal slope of the cell rack. The cells are such that the surface of a container of rectangular parallelepiped shape facing an end surface of a laminate electrode group adjoins an opposed surface of the inclined surface of the heat storage member.

Description

  The present invention relates to a secondary battery module in which a plurality of secondary battery cells are connected, and a secondary battery system using the same.

  In recent years, secondary batteries typified by lithium ion batteries and nickel metal hydride batteries have been changed from small electronic devices (for example, portable personal computers and mobile phones) to large electric devices (for example, HVE (hybrid vehicles) and EVs (electric vehicles)). The market is expanding to automotive power supplies, power storage power supplies, uninterruptible power supplies such as data centers, and natural energy power load leveling equipment such as solar power generation and wind power generation.

  In the application of secondary batteries to large electric devices, much higher output and capacity are required than in the case of small electronic devices. In addition to increasing the volume of the single battery (cell) of the secondary battery, it is necessary to connect a plurality of secondary batteries.

  In a secondary battery of a large electric device, usually, a plurality of cells are connected to constitute a secondary battery module, and a plurality of the secondary battery modules are connected to constitute a secondary battery system. In the case of a secondary battery module in which cells are connected in series, if there are variations in battery characteristics between cells, the battery characteristics and reliability of the entire system are limited to the cell with the lowest battery characteristics. For this reason, it is important to suppress variations in battery characteristics between cells.

  Secondary batteries usually generate heat during charging and discharging, and the battery temperature rises. In particular, in a lithium ion secondary battery, if the battery temperature rises to some extent, the battery performance deteriorates or the life is shortened. Therefore, it is necessary to cool the battery temperature so that it does not rise too much. Further, as the capacity and output of the secondary battery module and the secondary battery system increase, the problem of heat generation becomes larger. Therefore, efficient cooling is important.

  In response to the above-described requirements, research and development on a structure for efficiently cooling a secondary battery has been energetically advanced. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2009-259455) discloses an assembled battery that includes a plurality of chargeable / dischargeable single cells and a cooling mechanism that dissipates heat generated from the single cells to the outside. The unit cell has a configuration in which an electrode body in a form in which sheet-like electrodes are superimposed is housed in a container together with an electrolyte, and positive and negative electrode terminals are respectively connected to one end and the other end of the electrode body, An assembled battery is disclosed in which the cooling mechanism is configured so that the cooling efficiency of the central portion of the electrode body is higher than that of the positive electrode terminal connection side end and the negative electrode terminal connection side end of the electrode body. According to Patent Document 1, an assembled battery (typically, a lithium ion battery) that exhibits good durability even when used at a high rate by relaxing the temperature difference between the center and both ends of the unit cell. It is said that an assembled battery constructed as a single cell) can be provided, and a power supply system that can better maintain the performance of the assembled battery even when used at a high rate.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-291670) discloses a battery pack in which a plurality of secondary batteries are bundled and an electric wire is attached, and a heat storage material capable of conducting heat with the secondary battery in the battery pack. There is disclosed a battery pack characterized in that is disposed. According to Patent Document 2, it is said that a secondary battery that generates heat can be cooled stably and reliably.

JP 2009-259455 A JP 2002-291670 A

  In the assembled battery disclosed in Patent Document 1, since the cell temperature is reduced via a refrigerant (air or the like), electric power for driving a means (for example, a blower) for conveying the refrigerant is required. . Here, when the assembled battery is used as an uninterruptible power supply, it is necessary to supply power from the assembled battery in order to drive a blower or the like as described above at the time of a power failure when the external power supply is interrupted. . That is, there is a problem that the substantial output and capacity of the uninterruptible power supply are reduced. Furthermore, since the air warmed by the upstream cell of the air to be blown is supplied to the downstream cell, the cooling capacity decreases as it goes to the downstream side. There is a problem that is difficult.

  On the other hand, as described above, the demand for higher capacity and higher output for secondary battery modules and secondary battery systems has been increasing in recent years. As an example, an increase in capacity from the conventional 300 Ah to 500 Ah is required. For this reason, countermeasures against an increase in the amount of heat generated due to an increase in capacity and output are an extremely important issue.

  In addition, the number of cells to be incorporated increases as the capacity of the secondary battery module or the secondary battery system increases, but some cells may fail with a certain probability when used for a long time. At this time, it is very uneconomical to replace the entire secondary battery module or the entire secondary battery system with respect to some cell defects. In other words, in a system in which the number of cells to be incorporated is increased, it is economically meaningful to make it possible to easily replace the incorporated cells individually.

  In the battery pack disclosed in Patent Document 2, since individual cells are in contact with the heat storage material, it is expected to exhibit high cooling ability. However, because it is configured to cool a plurality of cells at once, it is difficult to replace the incorporated cells individually, and even if some cells fail, the entire battery pack needs to be replaced It is thought that there is. In other words, the battery pack of Patent Document 2 has a weakness that is inferior in economic efficiency when the capacity is increased.

  Accordingly, an object of the present invention is to efficiently incorporate individual cells in a secondary battery module in which a plurality of secondary battery cells are connected in order to cope with an increase in capacity and output of the secondary battery module. An object of the present invention is to provide a secondary battery module that cools and allows an incorporated cell to be replaced individually and easily. Another object of the present invention is to provide a secondary battery system using the secondary battery module.

In one aspect of the present invention, in order to achieve the above object, a plurality of secondary battery cells connected to each other, a plurality of heat storage members that abut against the cells and individually cool, a plurality of the cells, and A secondary battery module comprising a cell rack that houses the plurality of heat storage members,
The cell rack has a shape including a trapezoidal comb-tooth portion whose upper base is shorter than the lower base when viewed from the front, and accommodates the unit cell and the heat storage member between the comb-tooth portions. Configured as
The heat storage member has a wedge-shaped container having a heat storage material therein, and the wedge-shaped container has only one inclined surface, and the gradient of the inclined surface is a trapezoid of the comb tooth portion of the cell rack. Has the same slope as the slope,
The unit cell includes a laminated electrode group in which a positive electrode plate and a negative electrode plate are laminated, and a rectangular parallelepiped container that houses the laminated electrode group,
The heat storage member is disposed such that the inclined surface is in contact with the trapezoidal inclined surface of the cell rack, and the unit cell has a surface of the rectangular parallelepiped container facing the end surface of the stacked electrode group of the heat storage member. Provided is a secondary battery module, wherein the secondary battery module is disposed so as to be in contact with the opposite surface of the inclined surface.

Another embodiment of the present invention is a secondary battery system including a plurality of secondary battery modules in order to achieve the above object.
The secondary battery system is characterized in that the secondary battery modules are the secondary battery modules described above.

  According to the present invention, in a secondary battery module in which a plurality of cells of the secondary battery are connected, the incorporated individual cells are efficiently cooled, and the incorporated cells can be replaced individually and easily. Modules can be provided. Further, by using the secondary battery module, it is possible to provide a secondary battery system that is highly reliable and economical.

It is a partial see-through perspective schematic diagram showing an example of a unit cell used in the present invention. It is a perspective schematic diagram which shows an example of the laminated electrode group accommodated in a cell. It is a graph which shows the calculation result of the temperature distribution inside a cell at the time of generating heat at the center point of the cell. It is a perspective schematic diagram which shows an example of the secondary battery module which concerns on the 1st Embodiment of this invention. FIG. 5 is an assembly schematic diagram (front view) of the secondary battery module shown in FIG. 4. It is an assembly schematic diagram (front view) which shows an example of the secondary battery module which concerns on the 2nd Embodiment of this invention. It is a perspective schematic diagram which shows an example of the secondary battery module which concerns on the 3rd Embodiment of this invention. It is an assembly schematic diagram (perspective view) of the secondary battery module shown in FIG. It is a cross-sectional schematic diagram which shows an example of the secondary battery system which concerns on this invention provided with two or more secondary battery modules of this invention, (a) is front sectional drawing, (b) is side sectional drawing. It is a graph which shows the relationship between cell temperature and time.

The present invention can add the following improvements and changes to the secondary battery module according to the above-described invention.
(I) The cell rack further includes the heat storage material therein.
(Ii) The heat storage material is a phase change heat storage material.
(Iii) The heat storage material is any one of n-octadecane, n-nonadecane and n-eicosane.
(Iv) A radiating fin member is further provided on the surface of the rectangular parallelepiped container facing the front of the stacked electrode group of the unit cell.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments taken up here, and can be combined and improved as appropriate without departing from the technical idea of the invention.

[Example 1]
(Single cell)
First, a single cell (hereinafter also referred to as a cell) will be described. FIG. 1 is a partially transparent perspective schematic view showing an example of a unit cell used in the present invention. FIG. 2 is a schematic perspective view showing an example of the laminated electrode group housed in the unit cell. Note that, in this specification, a case where a lithium ion secondary battery is used as an example of a single battery will be described, but the present invention is not limited thereto.

  As shown in FIG. 2, the laminated electrode group 26 is configured by laminating a plurality of positive plates 204 and negative plates 205 via separators 203. The positive electrode plate 204 constituting the laminated electrode group 26 is made of a positive electrode active material mixture in which a binder (binder) is mixed with a positive electrode active material on both surfaces of a positive electrode foil (for example, an aluminum foil having a thickness of 20 to 30 μm). It has a positive electrode layer 206 formed by coating. Further, the positive electrode plate 204 includes a positive electrode tab portion 208 in which a part of the positive electrode foil is formed to extend in a rectangular shape.

  The negative electrode plate 205 constituting the laminated electrode group 26 is made of a negative electrode active material mixture in which a binder (binder) is mixed with a negative electrode active material on both sides of a negative electrode foil (for example, a copper foil having a thickness of 15 to 20 μm). The negative electrode layer 207 is formed by coating. Similarly to the positive electrode plate 204, the negative electrode plate 205 has a negative electrode tab portion 209 in which a part of the negative electrode foil is formed to extend in a rectangular shape. As the separator 203, for example, a porous polyethylene resin is used.

As shown in FIG. 1, the cell 20 includes a stacked electrode group 26 housed in a metal rectangular battery case 25. The positive electrode tab portions 208 of the stacked electrode group 26 housed in the rectangular parallelepiped battery case 25 are bundled to form a positive electrode current collector, and are connected to the positive electrode 21 that is an external electrode. Similarly, the negative electrode tab portions 209 of the accommodated laminated electrode group 26 are bundled to form a negative electrode current collector, and are connected to the negative electrode 22 that is an external electrode. Furthermore, a nonaqueous electrolytic solution (not shown) in which lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a mixed solvent of ethylene carbonate and dimethyl carbonate is injected into the rectangular battery case 25. In such a structure, charging / discharging is performed between the positive electrode active material and the negative electrode active material.

  Here, in the present invention, since the relationship between the direction of the stacked electrode group 26 in the cell 20 and the surface of the cell 20 that is actively cooled using the heat storage member is important, they are defined. In the laminated electrode group 26, the direction in which the positive electrode plate 204, the separator 203, and the negative electrode plate 205 are laminated (the normal direction of the surface) is defined as the lamination direction, and the positive electrode plate 204, the separator 203, and the negative electrode plate 205 are parallel to each other. The direction (direction orthogonal to the stacking direction) is defined as the in-plane direction.

  In the cell 20 and the rectangular battery container 25, the surface facing the stacking direction of the accommodated laminated electrode group 26 (the surface parallel to the flat plate constituting the laminated electrode group 26) is referred to as the front surface 23, and the positive electrode 21 and the negative electrode The surface having 22 is referred to as the upper surface, the opposite surface of the upper surface is referred to as the bottom surface 27, and the remaining two surfaces facing the in-plane direction of the stacked electrode group 26 are referred to as the side surfaces 24. In other words, the top surface, the bottom surface 27, and the side surface 24 can be said to be surfaces facing the end surface of the multilayer electrode group.

  As described above, since the laminated electrode group 26 is obtained by laminating the positive electrode plate 204, the separator 203, and the negative electrode plate 205, the equivalent thermal conductivity varies depending on the direction. Specifically, the equivalent thermal conductivity in the in-plane direction is high, but the equivalent thermal conductivity in the stacking direction is low. In order to estimate the influence of the equivalent thermal conductivity, the temperature distribution was calculated when it was assumed that heat was generated only at the center point of the cell 20 (that is, the center point of the laminated electrode group 26). The results are shown in FIG.

  FIG. 3 is a graph showing the calculation result of the temperature distribution inside the cell when heat is generated at the center point of the cell. As shown in FIG. 3, the in-plane direction of the laminated electrode group has a temperature distribution within 1 ° C., whereas the laminated direction of the laminated electrode group has a temperature distribution more than several times (at least 7 ° C.). I understand. From this calculation result, in order to effectively (efficiently) cool the cell 20 (ie, the laminated electrode group 26), the cell 20 (ie, the side electrode 24 and the bottom surface 27) is removed from the in-plane direction. It became clear that heating was desirable.

(Secondary battery module)
FIG. 4 is a schematic perspective view showing an example of the secondary battery module according to the first embodiment of the present invention. FIG. 5 is an assembly schematic diagram (front view) of the secondary battery module shown in FIG. 4. Here, as an example, a description will be given using a configuration in which three cells are connected and accommodated in one battery module.

  As shown in FIGS. 4 and 5, the secondary battery module 10 includes a plurality of cells 20, a heat storage member 30 that contacts the cells 20 and individually cools, and a cell rack 40 that houses the cells 20 and the heat storage member 30. It is equipped with. The cell rack 40 includes a cell support plate 42 for holding the cell 20 and the heat storage member 30 from the front direction. In the present invention, the cell support plate 42 is not an essential configuration, and the cell 20 and the heat storage member 30 may be held from the front direction by other methods and members.

  As described above, each of the cells 20a, 20b, and 20c has a rectangular parallelepiped shape, and the positive electrode terminals 21a, 21b, and 21c and the negative electrode terminals 22a, 22b, and 22c are disposed on the upper surface of the rectangular parallelepiped shape of the cell. Yes. When connecting battery cells 20a, 20b, and 20c in series, for example, the negative electrode 22a of the cell 20a and the positive electrode 21b of the battery cell 20b are connected by the bus bar 50, and the negative electrode 22b of the battery cell 20b and the positive electrode 21c of the battery cell 20c Are connected by a bus bar 50.

  The cell rack 40 has a shape including a trapezoidal comb tooth portion 41 whose upper base is shorter than the lower base when viewed from the front, and accommodates the cell 20 and the heat storage member 30 between the comb tooth portions 41. It is configured as follows. The comb tooth portion 41 has trapezoidal slopes 41a and 41b. There is no particular limitation on the material constituting the cell rack 40, but it is preferably made of metal from the viewpoint of heat dissipation. When the cell rack 40 is formed using a metal material, a hollow structure is preferable from the viewpoint of weight.

  The heat storage member 30 has a wedge-shaped container whose one surface is an inclined surface 30a, and includes a heat storage material therein. The slope 30a of the wedge-shaped container has the same slope as that of the trapezoidal slopes 41a and 41b of the comb teeth 41 of the cell rack 40. In other words, the wedge-shaped container of the heat storage member 30 has a trapezoidal shape in which the upper base 31a is longer than the lower base 31b and only one leg (corresponding to 30a) is a hypotenuse when viewed from the front. ing. The material constituting the wedge-shaped container of the heat storage member 30 is not particularly limited, but is preferably made of metal from the viewpoint of heat transfer.

  The heat storage member 30 is disposed so that the inclined surface 30a abuts on the trapezoidal inclined surfaces 41a and 41b of the comb tooth portion 41 of the cell rack 40, and the cell 20 is formed of the rectangular parallelepiped container 25 facing the end surface of the laminated electrode group 26. The side surface 24 is disposed so as to contact the facing surface 30b of the inclined surface 30a of the heat storage member 30.

  In the secondary battery module 10, when the cell 20 is fixed to the cell rack 40, the heat storage member 30 having a wedge shape is inserted between the comb teeth 41 together with the cells 20, thereby pressing the heat storage member 30 in the direction of the cell 20. A force is generated, and the contact thermal resistance between the cell 20 and the heat storage member 30 can be reduced. As a result, the heat generated from the cell 20 can be efficiently transmitted to the heat storage member 30. In order to further improve the adhesion between the cell 20 and the heat storage member 30, an elastic heat conductive sheet (for example, Shin-Etsu Chemical Co., Ltd., Shin-Etsu Silicone TC-A) is interposed, or heat conductive grease ( For example, Shin-Etsu Chemical Co., Ltd., Shin-Etsu Silicone G-750) may be applied.

  Further, since it is not necessary to manage the pressing pressure of the heat storage member 30 when the secondary battery module 10 is assembled, maintenance such as insertion and removal of the cell 20 is easy. Furthermore, since the contact pressure of each cell 20 in the secondary battery module 10 can be kept uniform, the cooling capacity of the heat storage member 30 with respect to the cell 20 becomes equal, and temperature variations among a plurality of incorporated cells 20 occur. Can be suppressed.

  That is, the secondary battery module 10 of the present invention has the above-described structure, so that the incorporated individual cells 20 can be efficiently cooled, and the incorporated cells 20 can be replaced individually and easily. be able to.

  As the heat storage material in the heat storage member 30, it is preferable to use a heat storage material having a specific heat as large as possible. Thereby, the volume of the heat storage material can be suppressed while securing a sufficient heat absorption amount (heat extraction amount). The suppression of the volume of the heat storage material can suppress an increase in the volume of the secondary battery module 10 as a whole, and can minimize a decrease in the volume output density of the secondary battery module 10 as a whole.

  Moreover, as the heat storage material, a phase change type heat storage material that changes phase from a solid phase to a liquid phase when absorbing heat and absorbs heat by the latent heat of the phase change can be preferably used. The phase change point at this time is desirably slightly higher than the environmental temperature (for example, 25 ° C.) in which the secondary battery module 10 is disposed (for example, preferably more than 25 ° C. and 40 ° C. or less). If the phase change point is 25 ° C. or less, the latent heat of phase change can hardly be used. When the phase change point is higher than 40 ° C., the timing for cooling the cell 20 is delayed and the cell 20 is likely to be overheated. As long as these conditions are satisfied, there is no particular limitation on the phase change type heat storage material. For example, n-octadecane (phase change point = 28.2 ° C), n-nonadecane (phase change point = 32.1 ° C) and n-eicosane ( (Phase change point = 36.8 ° C.) can be preferably used.

  The phase change type heat storage material increases in volume by about 10% when the phase changes. In order to prevent undesired deformation of the heat storage member 30 and undesired stress on the cell 20 due to this increase in volume, it is preferable to leave a gap corresponding to the volume change of the heat storage material in the heat storage member 30.

[Example 2]
(Secondary battery module)
A secondary battery module according to the second embodiment will be described. FIG. 6 is an assembly schematic diagram (front view) showing an example of a secondary battery module according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same member and site | part as previous 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 6, the secondary battery module 60 is different from the secondary battery module 10 in that the cell rack 45 includes a heat storage material 44 inside the comb teeth portion 43, and the rest is the same as the secondary battery module 10. It has the composition of. That is, the heat storage member 30 is disposed so that the inclined surface 30a contacts the trapezoidal inclined surfaces 43a and 43b of the comb teeth portion 43 of the cell rack 45, and the cell 20 is a rectangular parallelepiped container facing the end surface of the laminated electrode group 26. The 25 side surfaces 24 are disposed so as to contact the facing surface 30b of the inclined surface 30a of the heat storage member 30.

  According to the second embodiment, in addition to the operational effects shown in the first embodiment, since the volume of the heat storage material in the secondary battery module can be increased, more heat can be absorbed, It is possible to cope with further increase in capacity and output of the secondary battery module. Alternatively, the secondary battery module 20 can be reduced in size by reducing the volume of the heat storage member 30, and the volume output density can be improved as compared with the secondary battery module 10.

  In FIG. 6, the heat storage material 44 is added inside the comb tooth portion 43 of the cell rack 45, but a heat storage material may be further provided inside the base portion 46 between the comb tooth portions 43. Thereby, the cooling capacity can be further enhanced.

[Example 3]
(Secondary battery module)
A secondary battery module according to the third embodiment will be described. FIG. 7 is a schematic perspective view showing an example of the secondary battery module according to the third embodiment of the present invention. FIG. 8 is an assembly schematic diagram (perspective view) of the secondary battery module shown in FIG. 7. In addition, the same code | symbol is attached | subjected to the same member and site | part as previous 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIGS. 7 and 8, the secondary battery module 70 is different from the secondary battery module 10 in that a heat radiating fin member 75 is further provided on the front surface 23 of the cell 20. It has the same configuration. There is no particular limitation on the material constituting the radiating fin member 75, and a conventional high heat conductive material (for example, aluminum or copper) can be used.

  7 and 8, the radiating fin member 75 is in contact with only the front surface 23 of the cell 20. However, the present embodiment is not limited thereto, and for example, is in contact with the heat storage member 30 as well. Good. However, from the viewpoint of ease of replacement of the cell 20, the radiating fin member 75 is preferably a separate member for each cell 20.

  According to the third embodiment, in addition to the operational effects shown in the first embodiment, the cell 20 is more efficiently cooled by the heat radiation from the heat radiation fin member 75. As a result, the temperature of the cell 20 can be lowered more quickly, and the waiting time until recharging can be shortened. In addition, by fixing the front surface 23 of the cell 20 with the radiating fin member 75, a restraining force is generated with respect to the front direction of the cell 20, so that a secondary effect that deformation in the front direction of the cell 20 can be suppressed is also obtained. is there.

[Example 4]
(Secondary battery system)
Next, the secondary battery system according to the present invention will be described. A large-sized secondary battery system can be constructed by arranging and connecting a plurality of secondary battery modules according to the present invention. FIG. 9 is a schematic cross-sectional view showing an example of a secondary battery system according to the present invention including a plurality of secondary battery modules of the present invention, where (a) is a front cross-sectional view and (b) is a side cross-sectional view. .

  As shown in FIG. 9, in the secondary battery system 90, a plurality of secondary battery modules (for example, the secondary battery module 10) are disposed inside the housing 91 and connected to each other. The casing 91 includes an intake portion 92 for taking in cooling air inside and an exhaust fan 93 for discharging the internal air. The secondary battery modules 10 are arranged so that the cooling air flows smoothly on the front surface 23 of the cell 20. Thereby, cooling of the cell 20 can be promoted.

  Specifically, this embodiment has the following effects.

  (1) When the secondary battery system 90 of the present invention is used as, for example, a large uninterruptible power supply for a data center, a large amount of each cell 20 of the secondary battery module 10 is discharged when it is discharged due to an unexpected power failure. Joule heat is generated. The discharge time of the uninterruptible power supply depends on the design specifications, but is usually about 10 minutes.

  Even during the discharge, the secondary battery module 10 of the present invention can suppress an excessive increase in the temperature of the cell 20 by absorbing the heat generated from the cell 20 by the heat storage member 30. Further, since the heat generated from the cell 20 is individually absorbed by the heat storage member 30, the temperature rise of the air flowing in the casing 91 of the secondary battery system 90 can be suppressed. This leads to uniform cooling of the cells 20 in the housing 91, and temperature variations between the cells 20 can be suppressed. Furthermore, in the secondary battery module 10 of the present invention, since the heat storage member 30 is in contact with the side surface 24 of the cell 20 having a high equivalent thermal conductivity, the temperature distribution inside the cell 20 can also be kept small.

  (2) After the power failure is restored, the secondary battery system 90 is charged in preparation for the next discharge, but the temperature of the cell 20 needs to be sufficiently lowered before recharging. Here, it is not easy to lower the temperature of the cell 20 by cooling via the heat storage member 30 having low thermal conductivity. On the other hand, the secondary battery module 10 of the present invention has a structure in which the heat storage member 30 is not fixed to the front surface 23 of the cell 20. The equivalent thermal conductivity in the front 23 direction of the cell 20 is lower than that in the side 24 direction as described above, but is higher than the thermal conductivity of the heat storage member 30, and therefore the cell 20 is cooled from the front 23 by cooling air from the exhaust fan 93. 20 can be cooled. As a result, the temperature of the cell 20 can be quickly reduced.

  When no special cooling means is provided for the cell 20 (no cooling structure), when the heat radiation fin member 75 is provided on the front surface 23 (heat radiation fin cooling), when the heat storage member 30 is provided on the side surface 24 (heat storage member) Cooling), the time change of the cell temperature was calculated by simulation in four patterns of the case where the heat storage member 30 was provided on the side surface 24 and the heat radiation fin member 75 was provided on the front surface 23 (heat storage member cooling + radiation fin cooling). The boundary conditions were assumed to be an environment where the battery was discharged in 10 minutes and then left in the air to cool naturally. The results are shown in FIG.

  FIG. 10 is a graph showing the relationship between cell temperature and time. As shown in FIG. 10, in any case, the cell temperature rises due to Joule heat with the start of discharge, and the cell temperature gradually decreases after the end of discharge. Here, in the lithium ion secondary battery, it is generally said that the deterioration starts when the cell temperature becomes 50 ° C. or higher, and the deterioration accelerates when the cell temperature becomes 60 ° C. or higher. In other words, in order to prevent deterioration in battery performance and shortening of the cell life, it is desirable to suppress the cell temperature to less than 50 ° C.

  Looking at the calculation results from this point of view, in the case of “no cooling structure” or “radiating fin cooling”, the increase in cell temperature due to discharge exceeds 50 ° C., and the cell 20 deteriorates with each discharge. I know that On the other hand, in the case of “heat storage member cooling” and “heat storage member cooling + radiating fin cooling” according to the present invention, the maximum temperature during discharge is less than 50 ° C., and the cell 20 is not deteriorated even after repeated charge and discharge. I understand that. Furthermore, in the case of the present invention, since the temperature decrease after completion of discharge proceeds in a shorter time, recharging can be performed quickly.

  In the present specification, a lithium ion secondary battery has been described as an example of the cell 20, but the present invention is not limited thereto and can be applied to other secondary batteries. In the present invention, it is preferable to use the laminated electrode group 26 as the electrode group of the cell 20, but this does not deny the wound electrode group.

  The above-described embodiment has been specifically described to help understanding of the present invention, and the present invention is not limited to having all the configurations described. For example, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Furthermore, a part of the configuration of each embodiment can be deleted, replaced with another configuration, or added with another configuration.

10 ... Secondary battery module,
20 ... cell,
201 ... Positive electrode foil, 202 ... Negative electrode foil, 203 ... Separator, 204 ... Positive electrode plate, 205 ... Negative electrode plate,
206 ... Positive electrode layer, 207 ... Negative electrode layer, 208 ... Positive electrode tab, 209 ... Negative electrode tab,
21 ... Positive electrode, 22 ... Negative electrode, 23 ... Front, 24 ... Side, 25 ... Rectangular battery container,
26 ... Stacked electrode group, 27 ... Bottom,
30 ... thermal storage member, 30a ... inclined surface, 30b ... facing, 31a ... upper bottom, 31b ... lower bottom,
40 ... cell rack, 41 ... comb teeth, 41a, 41b ... trapezoidal slope, 42 ... cell support plate,
45 ... Cell rack, 43 ... Comb teeth part, 43a, 43b ... Trapezoidal slope, 44 ... Heat storage material, 46 ... Base part,
50 ... Bus bar,
60 ... secondary battery module,
70 ... secondary battery module, 75 ... heat dissipation fin member,
90 ... secondary battery system, 91 ... casing, 92 ... intake section, 93 ... exhaust fan.

Claims (6)

A plurality of rechargeable battery cells connected to each other; a plurality of heat storage members that abut against the cell and individually cool; and a cell rack that houses the plurality of cells and the heat storage members. A secondary battery module,
The cell rack has a shape including a trapezoidal comb-tooth portion whose upper base is shorter than the lower base when viewed from the front, and accommodates the unit cell and the heat storage member between the comb-tooth portions. Configured as
The heat storage member has a wedge-shaped container having a heat storage material therein, and the wedge-shaped container has only one inclined surface, and the gradient of the inclined surface is a trapezoid of the comb tooth portion of the cell rack. Has the same slope as the slope,
The unit cell includes a laminated electrode group in which a positive electrode plate and a negative electrode plate are laminated, and a rectangular parallelepiped container that houses the laminated electrode group,
The heat storage member is disposed such that the inclined surface is in contact with the trapezoidal inclined surface of the cell rack, and the unit cell has a surface of the rectangular parallelepiped container facing the end surface of the stacked electrode group of the heat storage member. A secondary battery module, wherein the secondary battery module is disposed so as to abut against the opposite surface of the inclined surface. The secondary battery module according to claim 1,
The cell rack further includes the heat storage material in the cell rack. The secondary battery module according to claim 1 or 2,
The secondary battery module, wherein the heat storage material is a phase change type heat storage material. The secondary battery module according to claim 3,
The secondary battery module, wherein the heat storage material is one of n-octadecane, n-nonadecane, and n-eicosane. The secondary battery module according to any one of claims 1 to 4,
A secondary battery module, wherein a radiation fin member is further provided on the surface of the rectangular parallelepiped container facing the front of the stacked electrode group of the unit cell. A secondary battery system comprising a plurality of secondary battery modules,
The secondary battery system according to any one of claims 1 to 5, wherein the plurality of secondary battery modules are secondary battery modules.

Images