JP2013222603A - Secondary battery, secondary battery module incorporating secondary battery and battery pack system incorporating secondary battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems in which temperature distribution in a lamination direction of battery cells becomes ununiform because thermal conduction in the lamination direction of the battery cells is small in comparison to thermal conduction in an electrode surface direction of the battery cells orthogonal to the lamination direction, and charging and discharging performance of the battery cells is reduced because degradation degrees accompanying charging and discharging of the battery cells become different between a battery cell part exposed to high temperature and a battery cell part at low temperature.SOLUTION: Endothermic means having an endothermic function is arranged on a surface in a direction orthogonal to a lamination direction in which battery cells are laminated (in other words, a surface parallel to the lamination direction), and a plurality of battery cells and the endothermic means are thermally connected. Since the endothermic means and each of the battery cells are thermally connected under the substantially same condition, heat generated in each battery cell is absorbed by the endothermic means at the rate of the same degree and ununiformity of the temperature distribution of each battery cell can be suppressed.

Description

  The present invention relates to a secondary battery, a secondary battery module incorporating a secondary battery, and an assembled battery system incorporating a secondary battery module, and more particularly, a secondary battery with improved cooling performance and a secondary battery incorporating a secondary battery. The present invention relates to a battery module and an assembled battery system incorporating a secondary battery module.

  Secondary batteries such as lithium ion batteries and nickel metal hydride batteries are used as secondary battery used as a backup power supply for computer systems, factories, offices, etc. It has been known.

  These secondary batteries have a phenomenon that heat is generated during charging and discharging and the temperature in the secondary battery rises, and the secondary battery is efficiently recharged because the charge / discharge performance of the secondary battery decreases with this temperature rise. The battery needs to be cooled.

  Various techniques have been proposed for cooling the secondary battery. Typically, a water cooling method using cooling water, an air cooling method using flowing air, and the like are well known. However, when employing a power supply device using many secondary batteries, it is important to further improve the cooling performance.

  In response to such a demand for improving the cooling performance, for example, Japanese Translation of PCT International Publication No. 2011-503794 (Patent Document 1) discloses cooling of a secondary battery composed of a plurality of plate-shaped battery cells that are continuously stacked. A structure is disclosed.

  In this secondary battery, each battery cell has an electrode group having a cathode / separator / anode structure, and these battery cells are mounted in a battery case formed of a laminate sheet including a resin layer and a metal layer.

  Then, in order to remove the heat generated from the battery cells during charging and discharging of the battery cells, heat including a frame in which a plurality of heat exchange plates are inserted and arranged between the battery cells and the heat exchange plates are connected. A secondary battery having a structure in which an exchange member is attached to one side of a battery cell is disclosed.

  In such a secondary battery, heat generated from the electrode group of the battery cell is absorbed by the heat exchange member via the heat exchange plate, and then the absorbed heat is discharged out of the secondary battery, The structure is cooled.

Special table 2011-503794 gazette

  By the way, in the secondary battery described in Patent Document 1, a plurality of heat exchange plates and heat exchange members are configured to be attached to one side of a structure in which battery cells are stacked. The battery can be cooled without requiring space.

  In the secondary battery described in Patent Document 1, heat generated in the electrode group is dissipated through a battery case formed from a laminate sheet or a heat exchange plate inserted between stacked battery cells. Is.

  However, in the case where many battery cells are used for a secondary battery formed by stacking battery cells in order to construct a large-scale battery system, the number of battery cells increases, so heat is easily generated inside the stacked battery cells, Even if a configuration in which heat is dissipated from the heat exchange plates inserted between the stacked battery cells is adopted, a large temperature imbalance state occurs in the battery cells. That is, there is a problem that different temperature regions are generated in the stacking direction of the stacked battery cells and the temperature distribution is not uniform.

  In a large-capacity secondary battery in which many battery cells are stacked, the heat conduction in the stacking direction of the battery cells is generally significantly smaller than the heat transfer in the electrode surface direction of the battery cell perpendicular to the stacking direction. For this reason, the temperature distribution in the stacking direction of the battery cells becomes non-uniform. Specifically, the temperature is high at the center in the stacking direction of the battery cells, and the temperature tends to decrease toward both ends in the stacking direction.

  Thus, when the temperature distribution becomes uneven inside the stacked battery cells, the degree of deterioration due to charging or discharging of the battery cells differs between the battery cell part exposed to high temperature and the battery cell part having relatively low temperature, If the battery is operated for a long period of time, the charge / discharge characteristics may be imbalanced inside the stacked battery cells, and the charge / discharge performance of the battery cells may be significantly reduced.

  Further, in the case of constructing a large-scale assembled battery system including a large number of secondary batteries made up of stacked battery cells, it is necessary to reduce the uneven temperature distribution between the secondary batteries. In other words, when some secondary batteries in an assembled battery system are exposed to high temperatures, the degree of deterioration of the secondary batteries will be different compared to other secondary batteries. There is a risk of worsening.

  In the secondary battery described in Patent Document 1, an increase in size can be achieved by stacking a large number of battery cells. However, in order to reduce non-uniform temperature distribution among a large number of secondary batteries, It is necessary to maintain the cooling air volume, the air temperature, the cooling water temperature, and the water volume at the same level between the secondary batteries, which complicates the cooling mechanism.

  An object of the present invention is to provide a secondary battery that employs a novel cooling method that suppresses uneven temperature distribution between battery cells, a secondary battery module that incorporates a secondary battery, and a set that incorporates a secondary battery module. It is to provide a battery system.

  A feature of the present invention is that a plurality of battery cells and the heat absorbing means are heated by disposing heat absorbing means having a heat absorbing function on a surface perpendicular to the stacking direction in which the battery cells are stacked (in other words, a surface parallel to the stacking direction). Connected.

According to the present invention, the heat absorption means and each battery cell are thermally connected under substantially the same conditions, so that the heat generated in each battery cell is absorbed by the heat absorption means at the same rate. Thus, it becomes possible to suppress the non-uniform temperature distribution of each battery cell.

It is a perspective view of the secondary battery module which combined the secondary battery provided with the some battery cell which becomes one Example of this invention. It is a front view of the assembled battery system provided with the some secondary battery module which becomes one Example of this invention. It is a side view of the assembled battery system shown in FIG. It is the disassembled perspective view which decomposed | disassembled the secondary battery module shown in FIG. 1 clearly. FIG. 2 is a partially broken perspective view of a secondary battery in which the secondary battery shown in FIG. 1 is partially cut away. FIG. 6 is a perspective view showing an internal structure of the secondary battery shown in FIG. 5. It is a perspective view which shows the structure of the electrode group of the battery cell in the secondary battery shown in FIG. It is a perspective view which shows the internal structure of the secondary battery which is the other Example of this invention. It is a perspective view which shows the structure of the internal heat conductive member shown in FIG. It is a perspective view of the secondary battery module which combined the secondary battery provided with the some battery cell which becomes the other Example of this invention. It is sectional drawing of the secondary battery module shown in FIG. It is a front view of the assembled battery system provided with the some secondary battery module which becomes the other Example of this invention. It is a side view of the assembled battery system shown in FIG. The other Example of a secondary battery is shown and it is a partially broken perspective view of a secondary battery.

  Hereinafter, a secondary battery and an assembled battery system using the secondary battery according to an embodiment of the present invention will be described in detail with reference to the drawings.

  The embodiment described below is a prismatic lithium ion secondary battery in which battery cells are stacked, and a stationary assembled battery system in which a plurality of prismatic lithium ion secondary batteries are combined. However, the present invention is not limited to the secondary battery or the assembled battery system as in this embodiment, and various applications are possible.

  In addition, although several Example is proposed in this invention, the same reference number has shown the same component or the component provided with the similar function.

  FIG. 1 is a configuration diagram of a secondary battery according to the first embodiment of the present invention and a secondary battery module 160 including a plurality of secondary batteries. 2 is a front view of the assembled battery system 161 having a plurality of secondary battery modules 160 as viewed from the front, and FIG. 3 is a side view of the assembled battery system 161 as viewed from the side.

  As shown in FIGS. 2 and 3, the assembled battery system 161 is a substantially rectangular parallelepiped casing, and a plurality of secondary battery modules 160 are installed at predetermined positions, and a plurality of shelves are provided in the height direction. 162, an air intake section 163 for taking cooling air into the housing, a cooling fan 164 for discharging air from the housing, and a battery pack for controlling a plurality of secondary battery modules 160 to extract predetermined power A controller 166 is provided.

  In FIG. 2 and FIG. 3, the secondary battery module 160 is another secondary battery electrically connected in series or in parallel by a bus bar which is an electric wiring or a metal conductive member (not shown) to obtain a predetermined voltage and current. The module 160 or the assembled battery controller 166 is connected.

  The assembled battery controller 166 controls the plurality of secondary battery modules 160 in order to supply predetermined power to the outside via the power extraction terminal 168.

The assembled battery system 161 supplies the power charged in the secondary battery module 160 to the outside when power supply to the outside is necessary. When the secondary battery module 160 needs to be charged, the secondary battery module 160 is charged with electric power supplied from the outside. The discharge of the secondary battery module 160 is used as a backup power source when the computer system goes down due to a power failure, for example. Further, when charging or discharging from a commercial power source to function as a backup power source, the cooling fan 164 operates, and the air taken into the housing from the opening 163 by the cooling fan 164 is the shelf or the ceiling of the housing. The secondary battery module 160 is cooled by flowing through a substantially duct-shaped space constituted by the side surfaces of the housing and the periphery of the secondary battery module 160 disposed on the shelf 162.

  As shown in FIG. 1, the secondary battery module 160 includes a plurality of secondary batteries 100A to 100D arranged in series, and each of the secondary batteries 100A to 100D has a substantially rectangular parallelepiped shape, each having an upper surface portion, It consists of two pairs of side parts and a bottom part.

  A positive electrode terminal 141 and a negative electrode terminal 151 are provided on the upper surface portion, and one pair of side surface portions is a facing surface of each of the secondary batteries 100A to 100D, and the other pair of side surface portions is provided with heat absorbing means 135 that absorbs heat. It is attached, and the bottom portion is placed on the housing. The heat absorbing means 135 will be described in detail later.

  In the secondary batteries 100A and 100C, the positive electrode terminal 141 is disposed on the lower side in the drawing, and the negative electrode terminal 151 is disposed on the upper side in the drawing. In the secondary batteries 100B and 100D, the negative electrode terminal 151 is disposed on the lower side in the drawing, The positive terminal 141 is arranged on the upper side in the drawing. That is, the plurality of secondary batteries 100A to 100D arranged in parallel are arranged with their directions reversed so that the positions of the positive terminal 141 and the negative terminal 151 attached to each of the secondary batteries 100A to 100D are reversed. ing.

  As shown in FIG. 1, adjacent secondary batteries 100 </ b> A to 100 </ b> D except for the positive electrode terminal 141 on the lower side on the drawing of the secondary battery 100 </ b> A and the negative electrode terminal 151 on the lower side on the drawing of the secondary battery 100 </ b> D. The positive electrode terminal 141 and the negative electrode terminal 151 are electrically connected by a bus bar 109 which is a metal plate-like conductive member.

  In the positive electrode terminal 141 and the negative electrode terminal 151, male screws are formed in portions exposed to the outside of the battery container, and a bus bar 109 for electrically connecting the secondary batteries is connected to the positive electrode terminal by a nut (not shown). 141 and the negative terminal 151 are fixedly connected. The bus bar 109 may be connected to the positive terminal 141 and the negative terminal 151 by laser welding, electron beam welding, or the like.

  The lower positive terminal 141 on the secondary battery 100A shown in FIG. 1 and the lower negative terminal 151 on the secondary battery 100D are electrically connected to other battery modules 160 in series or in parallel. 2 or connected to the power controller 16 shown in FIG. 2 via an electrical wiring or bus bar (not shown).

  The secondary battery module 160 also holds the battery bottom holding member 122 for holding the secondary batteries 100A to 100D at the bottom, the battery side holding member 124 for holding from the side, and the secondary batteries 100A and 100D from the outside. Module end holding member 123 and a spacer 121 for maintaining a predetermined distance between the secondary batteries 100A to 100D, and the secondary batteries 100A to 100D are held at predetermined positions in the battery module 160.

  The secondary battery module controller 120 monitors the operating state of the secondary batteries 100 </ b> A to 100 </ b> D and controls charging / discharging of the secondary battery module 160 as necessary, or transmits a signal for controlling to the assembled battery controller 166. It has a function to do.

  In addition, the secondary battery module 160 includes a heat absorption means 135, a heat dissipation promotion means 137, and a heat absorption means holding member 136 for holding them on the side surfaces of the secondary batteries 100A to 100D.

  FIG. 4 is an exploded view in which the heat dissipation promotion means 137 and the heat absorption means holding member 136 are separated to facilitate understanding of the positional relationship among the heat absorption means 135, the heat dissipation promotion means 137, and the heat absorption means holding member 136 shown in FIG. .

  The heat absorbing means 135 is fixed to both sides of a pair of side surface portions 101b different from the side surfaces to which the secondary batteries 100A to 100D are opposed. As this fixing method, for example, a method of sticking with a material having low thermal resistance and good heat conductivity is employed. The component to be attached is preferably as thin as possible and has good thermal conductivity, and examples of satisfying such conditions include double-sided tape and sheet having high thermal conductivity, but are not particularly limited. However, it is desirable to use a silicon-based resin sheet, a heat transfer sheet containing a heat transfer ceramic (metal oxide) powder having an insulating property, or the like based on past use records.

  Note that, if it can be held by a heat absorbing means holding member 136 described later, there is no need for an attaching means, but heat transfer between the side surface portion 101b of the secondary batteries 100A to 100D and the heat absorbing means 135 is not performed via air. It is more realistic to intervene with a heat transfer sheet having flexibility.

  Further, a heat radiation promoting means 137 is attached and fixed outside the heat absorbing means 135. As a component for attachment, a fixing method between the heat absorbing means 135 and the side surface portion 101b of the secondary batteries 100A to 100D may be used. For example, a method of attaching with a material having low thermal resistance and good heat conductivity. Is adopted. The component to be attached is preferably as thin as possible and has good thermal conductivity, and examples of satisfying such conditions include double-sided tape and sheet having high thermal conductivity, but are not particularly limited. However, it is desirable to use a silicon-based resin sheet, a heat transfer sheet containing a heat transfer ceramic (metal oxide) powder having an insulating property, or the like based on past use records.

  Therefore, the side surface portions 101b of the secondary batteries 100A to 100D, the heat absorbing means 135, and the heat dissipation promoting means 137 are thermally connected.

  The heat radiation promoting means 137 is further pressed from the outside toward the side surface portion 101b of the secondary battery by the heat absorbing means holding member 136 through the elastic member 138.

  The elastic member 138 has a characteristic capable of expanding and contracting itself, and has a function of absorbing the expansion and contraction movement of the heat absorbing means 135 in addition to the function of pressing the heat radiation promoting means 137 against the side surface portion 101b. ing.

  That is, the elastic member 138 can expand and contract in the pressing direction in order to maintain a good contact state between the heat absorbing means 135 and the side surface portion 101b of the secondary battery even when the heat absorbing means 135 expands or contracts.

  For example, although the endothermic agent constituting the endothermic means 135 depends on the composition, a volume change of about 10% occurs when an endothermic agent mainly composed of paraffin described later is used.

  A material that satisfies such a condition is a rubber material, and a spring that can be deformed in the pressing direction may be used. That is, the elastic member 138 maintains a good contact state between the heat absorbing means 135, the side surface portion 101b of the secondary battery, and the heat radiation promoting means 137, so that even if the heat absorbing means 135 expands and contracts, A good connection state can be maintained.

  Further, since the heat absorption means 135 mainly expands and contracts, the heat absorption means 135 may be directly held by the heat absorption means holding member 136 and the elastic member 138, or the heat dissipation promotion means 137 is not provided. Even in such a case, the heat absorbing means 135 may be directly held by the heat absorbing means holding member 136 and the elastic member 138.

  The heat absorbing means 135 performs a function of absorbing heat over substantially the entire side surface 101b of the secondary batteries 100A to 100D. That is, it has a function of absorbing heat generated by the battery cells stacked inside the secondary batteries 100A to 100D and dissipating the heat to the outside.

  The heat absorbing means 135 is configured, for example, by enclosing an endothermic gel as an endothermic agent in an aluminum sheet container housed in a rigid aluminum frame body, and heat inside the secondary batteries 100A to 100D. Is absorbed by the endothermic gel through the aluminum material having high thermal conductivity, and diffuses throughout the endothermic gel and functions to dissipate heat.

  The frame can be omitted if the housing can be designed with relatively high rigidity, and various changes and applications can be made according to the design guidelines for the secondary batteries 100A to 100D.

  In this way, the temperature is decreased over almost the entire side surface portion 101b of the secondary battery by the heat absorbing means 135, and as a result, the inner side surface corresponding to the side surface portion 101b is substantially within the casing of the secondary battery in which the battery cells are stacked. A temperature gradient can be created uniformly between the battery cells. This will be described in more detail later.

  Since the endothermic agent that constitutes the endothermic means 135 is required to absorb the heat generated in the battery cell, it is important to increase the amount of heat that can be absorbed, and it is a material having a specific heat as high as possible. It is desirable. Therefore, it is necessary to have at least a substantial specific heat of the battery cell, that is, a specific heat higher than a value obtained by dividing the heat capacity of the battery cell by the weight of the battery cell.

  A more desirable material as an endothermic agent of the endothermic means 135 is a material having a phase change endothermic function that melts or vaporizes when absorbing heat and absorbs heat by latent heat at the time of the phase change.

  A material having a phase change endothermic function is exposed to the battery module or the assembled battery system in a state where the phase changes at a temperature lower than the temperature that rises due to the heat generated when the battery cell is charged and discharged and the battery cell is not charged or discharged. It is necessary that the phase does not change at the ambient temperature.

  That is, when the ambient temperature is 25 ° C., for example, it is desirable that the material change phase at about 30 ° C. to 40 ° C. Further, in order to uniformly absorb heat while keeping the side surfaces of the stacked battery cells at a predetermined temperature, it is desirable that the temperature range in which the phase change occurs is as small as possible.

  Further, it is desirable that the endothermic agent constituting the endothermic means 135 has a high thermal conductivity. When the thermal conductivity is low, even if heat is absorbed from the side surface of the battery cell, the heat becomes difficult to be transmitted through the endothermic agent, and the endothermic agent is not effectively used for endotherm. Moreover, the heat absorbed by the heat absorbing agent is not easily transmitted to the heat dissipation heat transfer surface, and the heat dissipation efficiency from the heat dissipation heat transfer surface is reduced. For this reason, the thermal conductivity is desirably 2 W / mK or more.

  As a material used for the endothermic agent of the endothermic means that satisfies the above conditions, paraffin having a high latent heat is the main material, an additive for adjusting the phase change temperature, graphite or metal oxide particles for increasing the thermal conductivity, etc. Examples thereof include a filler and a mixed material to which a polymer resin or a rubber material for enhancing shape retention after phase change is added.

  In addition to paraffin, calcium chloride hydrate or sodium sulfate hydrate may be used as a main material. Further, the heat absorbing means 135 is formed by laminating or covering these mixed materials with an aluminum film having low gas permeability, so that the heat absorbing means 135 is easy to handle and has good assemblability.

  The amount or thickness of the heat absorbing agent of the heat absorbing means 135 is not particularly limited, and varies depending on the use of the assembled battery system. For example, when the assembled battery system is used as an emergency backup power supply device in the event of a power failure in a data center where a large number of computers are arranged, it is necessary to discharge the computer for a time until the computer can be safely stopped, for example, about 10 minutes. This time is allocated to the time for data transfer, storage in memory, backup data transfer, storage, and the like.

  In such an application, it is only necessary to absorb the heat generated in the battery cell for 10 minutes, but in a short time of 10 minutes, there is also heat that remains inside the battery cell and does not come out of the battery cell. That is, there is a part in which the temperature rise is suppressed by the heat capacity inside the battery cell itself. Therefore, a sufficient temperature reduction effect can be obtained if heat of about one fifth or more of the total amount of heat generated in about 10 minutes can be absorbed.

  When a material having a phase change endothermic function is used as the endothermic agent, a latent heat amount of about 100,000 J / kg can be easily achieved.

  With an assembled battery system comprising a large number of secondary batteries (height 0.15 m, depth 0.08 m, width 0.15 m), the density of the endothermic agent is 800 kg / m 3 and the latent heat amount is 100,000 J / kg. Assume that one secondary battery has a heat generation of 200 W during a discharge time of one minute.

  At this time, the amount of heat generated by one secondary battery in 10 minutes is 120,000 J. If this one-fifth is absorbed by the endothermic agent, the required endothermic agent weight is 120,000 / 100000/5 = 0.24 kg.

  Furthermore, since the dimension of the side surface portion of the secondary battery is 0.15 m × 0.08 m, the thickness of the necessary endothermic agent can be obtained by attaching the endothermic agent (encapsulated in the container) to the side surface portion. Is 0.24 / (800 × 0.15 × 0.08) = 0.025 m (= 2.5 cm). Since the endothermic agent is provided on both sides of the side part of the secondary battery, the necessary thickness of each endothermic agent is 0.0125 m (= 1.25 cm), and the endothermic agent has a sufficiently small size compared to the size of the secondary battery. Can absorb heat.

  The heat radiation promoting means 137 has a function of finally radiating the heat temporarily absorbed by the heat absorbing means 135 to the surrounding air. Therefore, the heat radiation promoting means 137 is thermally connected to one surface of the heat absorbing means 135, and further, as shown in FIGS. 1 to 3, an enlarged heat transfer in which fin-shaped irregularities are provided in a portion not in contact with the heat absorbing means 135 Has a surface.

  Heat dissipation can be promoted by expanding the heat dissipation area by providing an enlarged heat transfer surface having irregularities on the surface in contact with the air outside the secondary battery module 160. In this case, the enlarged heat transfer surface is desirably a material having high thermal conductivity in order to increase heat dissipation efficiency, and such material is, for example, copper, aluminum, or an aluminum alloy.

  Next, the secondary batteries 100A to 100D constituting the secondary battery module 160 will be described. Since the secondary batteries 100A to 100D have the same structure, the secondary battery 100A will be described as a representative.

  FIG. 5 is a partially broken perspective view showing the secondary battery 100A, in which the can 101 and a part of the lid 102 are cut away. FIG. 6 is a perspective view showing the internal structure of the battery cell 100A. FIG. 7 is a perspective view showing the configuration of the electrode group 170.

  As shown in FIG. 5, the secondary battery 100 </ b> A includes a battery container including a can 101 made of a plate material having a predetermined thickness and a lid 102. The material of the can 101 and the lid 102 is stainless steel, aluminum, aluminum alloy, or the like. The can 101 accommodates an electrode group 170 connected to the positive electrode current collector 180 and the negative electrode current collector 190 shown in FIG.

As shown in FIG. 5, the can 101 is formed in a rectangular box shape (substantially rectangular parallelepiped shape) having an open top surface, and has a pair of side wall portions 101a, a pair of side wall portions 101b, and a bottom wall portion. The heat absorbing means 135 is attached to the pair of side wall portions 101b so as to be thermally connectable. Here, a pair of side wall part 101a forms each opposing surface of secondary battery 100A-100D. (Hereinafter, the side wall portion is referred to as a side surface portion, and the bottom wall portion is referred to as a bottom surface portion.)
In the can 101, the electrode group 170 is configured and accommodated in a shape that follows the shape of the can 101. In the present embodiment, the electrode group 170 includes the first divided electrode group 170a and the second divided electrode group 170b. And is equally divided.

  As shown in FIGS. 5 and 6, the first divided electrode group 170 a and the second divided electrode group 170 b are accommodated in the can 101 while being covered with the insulating film 108. The insulating film 108 is an insulating resin film having a thickness of about 100 μm, such as polypropylene, and the bottom surface of the electrode group 170 is also covered with the insulating film, although not shown. Thereby, the can 101 and the electrode group 170 are electrically insulated.

  As shown in FIG. 5, the lid 102 has a rectangular flat plate shape and is welded so as to close the opening of the can 101. That is, the lid 102 seals the can 101.

  The lid 102 is provided with a positive electrode terminal 141 electrically connected to the positive electrode plate 174 of the electrode group 170 and a negative electrode terminal 151 electrically connected to the negative electrode plate 175 of the electrode group 170. The positive electrode terminal 141 and the negative electrode terminal 151 are respectively provided on the same installation surface of the battery container.

  Since the positive electrode terminal 141 is electrically connected to the positive electrode plate 174 of the electrode group 170 and the negative electrode terminal 151 is electrically connected to the negative electrode plate 175 of the electrode group 170, the positive electrode terminal 141 is externally connected via the positive electrode terminal 141 and the negative electrode terminal 151. Is supplied to the electrode group 170 via the positive electrode terminal 141 and the negative electrode terminal 151 for charging.

As shown in FIG. 5, the lid 102 is provided with a liquid injection unit 106. The liquid injection part 106 has a liquid injection hole for injecting an electrolyte into the battery container. The liquid injection hole is sealed with a liquid injection plug after the electrolyte is injected. As the electrolytic solution, for example, a nonaqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a mixed solvent of ethylene carbonate and dimethyl carbonate can be used.

  The lid 102 is also provided with a gas discharge valve 103. The gas discharge valve 103 is formed by partially thinning the lid 102 by pressing. The gas discharge valve 103 is heated when the secondary battery 100A generates heat due to an abnormality such as overcharge, and when the pressure in the battery container rises and reaches a predetermined pressure, the gas discharge valve 103 is opened and discharges the gas from the inside. By doing so, the pressure in the battery container is reduced. In addition, it is good also as providing the opening for gas exhaust valves in the lid | cover 102, and attaching the gas exhaust valve thinner than the cover 102 to the opening for gas exhaust valves by welding.

  Next, the structure of the electrode group 170 which is an electrical storage element is demonstrated with reference to FIG. As described above, the electrode group 170 of the present embodiment is divided into the first divided electrode group 170a and the second divided electrode group 170b. Since the first divided electrode group 170a and the second divided electrode group 170b have the same structure, the first divided electrode group 170a will be described below as a representative.

  FIG. 7 is a conceptual diagram for explaining a laminated structure of the first divided electrode group 170a. FIG. 7 shows a plurality of positive plates 174 and a plurality of negative plates 175 constituting the first divided electrode group 170a. A plurality of separators 173 interposed between the positive and negative electrode plates 174 and the negative electrode plate 175 are schematically shown. The battery cell laminated | stacked by these is comprised. That is, a unit battery cell is constituted by one positive electrode plate 174, one negative electrode plate 175, and a separator 173 interposed therebetween.

  As described above, the first divided electrode group 170a is manufactured by alternately stacking unit battery cells with the separator 173 interposed between the positive electrode plate 174 and the negative electrode plate 175, as shown in FIG.

  The positive electrode plate 174 includes a positive electrode foil 171 and a positive electrode layer 176 formed by applying a positive electrode active material mixture in which a positive electrode active material is mixed with a binder (binder) to both surfaces of the positive electrode foil 171.

  The negative electrode plate 175 includes a negative electrode foil 172 and a negative electrode layer 177 formed by applying a negative electrode active material mixture in which a binder (binder) is mixed with a negative electrode active material on both surfaces of the negative electrode foil 172. Charging / discharging is performed between the positive electrode active material and the negative electrode active material.

  The positive foil 171 is an aluminum foil having a thickness of about 20 to 30 μm, the negative foil 172 is a copper foil having a thickness of about 15 to 20 μm, and the material of the separator 173 is a porous polyethylene resin.

  The positive electrode plate 174 extends upward from one end (the left side in the figure) of the coating portion in which a rectangular active material mixture having a positive electrode layer 176 formed on both surfaces of the positive electrode foil 171 is applied. And an uncoated part that has been put out. The uncoated portion of the positive electrode plate 174 is a positive electrode current collector portion in which the positive electrode foil 171 is exposed without forming the positive electrode layer 176. Hereinafter, this positive electrode current collector portion is referred to as a positive electrode tab 178.

  The negative electrode plate 175 extends upward from one end (the right side in the figure) of the coated portion in which a rectangular active material mixture having a negative electrode layer 177 formed on both surfaces of the negative electrode foil 172 is applied. And an uncoated part that has been put out. The uncoated portion of the negative electrode plate 175 is a negative electrode current collector portion in which the negative electrode foil 172 is exposed without forming the negative electrode layer 177. Hereinafter, this negative electrode current collector portion is referred to as a negative electrode tab 179.

  As shown in FIG. 7, each of the positive and negative terminals 141 and 151 is a cylindrical member, and is inserted into the opening for attaching the positive and negative terminals of the lid 102 via the seal member 142, respectively. The material of the sealing material is an insulating resin such as polybutylene terephthalate, polyphenylene sulfide, perfluoroalkoxy fluororesin. As a result, the gap between the lid 102 and the positive and negative terminals 141 and 151 is sealed, and the positive and negative terminals 141 and 151 and the lid 102 are electrically insulated.

  The positive electrode current collector 180 and the negative electrode current collector 190 are members having a substantially rectangular parallelepiped shape, and are electrically connected to the positive electrode terminal 141 and the negative electrode terminal 151, respectively. The positive electrode current collector 180 and the negative electrode current collector are electrically connected to the positive electrode tab 178 and the negative electrode tab 179, respectively.

  When the unit battery cell including the positive electrode plate 174, the negative electrode plate 175, and the separator 173 is laminated to form a secondary battery, the heat generated in each battery cell flows in the lamination direction. Thus, the battery cell itself (particularly a separator or active material having low thermal conductivity) hinders heat transfer in the stacking direction. Therefore, when a large number of battery cells are stacked, the temperature distribution becomes non-uniform in the stacking direction, causing the above-described problems.

  Therefore, it is important to provide a heat dissipation structure that can quickly dissipate heat from the stacked battery cells and suppress the temperature distribution from becoming unbalanced. The structure will be described below.

  Returning to FIG. 5, each electrode group 170 is composed of stacked plate-shaped unit battery cells, and the stacking direction is the same as the side surface portion 101 b. That is, the relationship between the extending direction, which is the lateral direction of the battery cells of the electrode group 170, and the side surface portion 101b is orthogonal.

  On the other hand, there is the other pair of side surface portions 101a in the stacking direction of each electrode group 170, and the relationship between the extending direction of the battery cells of the electrode group 170 and the side surface portion 101a is a parallel relationship. The pair of side surface portions 101a faces the side surface portion 101a of the adjacent secondary battery.

  As shown in FIGS. 1 and 4, the heat absorbing means 135 is attached to almost the entire surface of the pair of side surface portions 101 b, and the side surface portions 101 b are almost uniformly close to the temperature of the heat absorbing means 135. ing.

  Therefore, the inner side surface, which is the inner side of the side surface portion 101b of the can 101, is almost uniformly close to the temperature of the heat absorbing means 135. For this reason, the extending | stretching direction of each plate-shaped battery cell which comprises the electrode group 170 faces the internal side surface of the side part 101b on the substantially the same conditions.

  As a result, each plate-shaped battery cell and the inner side surface of the side surface portion 101b have substantially the same temperature gradient, and the heat generated in each battery cell mainly passes through the positive electrode plate 174 and the negative electrode plate 175. It flows to the side surface portion 101b at a similar rate and further flows toward the heat absorbing means 135. That is, since the positive electrode plate 174 and the negative electrode plate 175 are made of a material including aluminum foil and copper foil, the heat transfer performance is excellent.

  For this reason, in the past, the heat generated easily in the vicinity of the center of the stacked battery cells as seen in the stacking direction of the battery cells, whereas in the case of this embodiment, the heat generated in each battery cell is at the same rate. Since the heat flows from the side surface portion 101b to the heat absorbing means 135, the temperature distribution of the stacked battery cells can be made substantially uniform. The heat absorbing means 135 may be disposed on at least one side surface portion 101b of the pair of side surface portions 101b of the secondary battery.

  Next, when this embodiment is summarized, the following operations and effects can be achieved.

  (1) When the secondary batteries 100 </ b> A to 100 </ b> D are discharged or charged, heat is generated inside the electrode group 170. Part of this heat is released to the outside from the lid 102 and terminals 141 and 151, and the rest is transferred to the can 101 via the insulating film 108.

  Since the heat absorbing means 135 is disposed on the side surface portion 101 b and the heat is absorbed by the heat absorbing means 135, the side surface portion 101 b is maintained at a lower temperature than when the heat absorbing means 135 is not provided. Therefore, the heat generated in the electrode group 170 is more easily released from the side surface portion 101b to the outside of the secondary battery than the side surface portion 101a as compared with the case where the heat absorbing means 135 is not provided.

  Here, the electrode group 170 is produced by alternately laminating the positive electrode plate 174 and the negative electrode plate 175 with the separator 173 interposed therebetween, and is arranged in parallel with the side surface portion 101a. Since the positive electrode plate and the negative electrode plate are composed of members including aluminum foil and copper foil, the thermal conductivity of the electrode group is large in a plane perpendicular to the stacking direction. On the other hand, since heat must pass through a member having low thermal conductivity such as an active material and a separator in the stacking direction, the heat conductivity in the stacking direction is very small.

  For this reason, for example, when the battery cell is cooled so that the temperature of the side surface portion 101a is lower than that of the side surface portion 101b, the heat moves in the stacking direction of the electrode group, and the temperature distribution in the stacking direction becomes large in the electrode group. Will occur.

  On the other hand, when the heat absorbing means 135 is disposed on the side surface portion 101b and the heat is absorbed from the side surface portion 101b as in the present embodiment, the heat of each battery cell is a surface perpendicular to the stacking direction of the electrode group. Since it moves at the same rate in the direction, it is possible to quickly cool the battery cell while suppressing non-uniform temperature distribution inside the electrode group.

  Although the heat absorption means 135 absorbs heat, the amount of absorption is determined by the characteristics and amount of the heat absorption means 135 and cannot absorb heat indefinitely. However, heat generation becomes a problem when the charge / discharge rate for discharging or charging with high power is high. A battery has a limited capacity, and discharging or charging with high power is a limited time. Therefore, the battery cell can be cooled by temporarily absorbing the heat by the heat absorbing means.

  (2) When used as a temporary power source in the event of a power failure as in a data center where a large number of computers are arranged, the effects of arranging the heat absorbing means 135 on the side surface portion 101b of the secondary batteries 100A to 100D are as follows: There is something.

  In such an application, the battery system is in a standby state on a daily basis, and a short time of about 10 minutes at the time of a power failure (for example, the time until the system can be safely shut down), the full capacity possible at a high discharge rate. Discharged. And since the assembled battery system does not operate immediately after the power failure is restored, charging may be performed over time in preparation for the next power failure.

  Therefore, in such an application, by disposing the heat absorbing means 135 on the side surface 101b, the heat absorption means 135 temporarily absorbs heat, thereby suppressing uneven temperature distribution inside the electrode group. Further, not only cooling of the battery cells can be realized, but also the heat absorbed by the heat absorbing means 135 can be radiated to the outside over time during standby after the end of the discharge, so that the heat radiating means can be simplified.

  (3) In particular, the temperature of the side surface portion 101b of the secondary batteries 100A to 100D can be kept more constant by using phase change heat absorption means that changes phase in a specific temperature range and absorbs heat as latent heat. .

  That is, when the secondary battery module 160 is configured without using the heat absorbing means 135 and is cooled by ventilating air from the outside, the generated heat is not generated even if the cooling air is maintained at a low temperature on the upstream side of the ventilation. As the air is absorbed, the air temperature on the downstream side rises, and the cooling efficiency decreases as the downstream side becomes uneven, resulting in non-uniform cooling efficiency among the secondary batteries 100A to 100D in the secondary battery module 160. The temperature distribution between the secondary batteries in the secondary battery module 160 becomes non-uniform.

  Similarly, when the assembled battery system 161 composed of a large number of battery modules 160 is configured, it is difficult to keep the cooling conditions such as the air volume and the air temperature uniform in all the secondary battery modules 160. Therefore, nonuniform temperature distribution occurs between the secondary battery modules 160.

  In addition, although the above description assumes ventilation of cooling air, even when a cooling refrigerant such as water is passed through to dissipate heat, the water temperature rises and the amount of water becomes uneven, and the secondary battery module Nonuniform temperature distribution occurs between the secondary batteries 100 </ b> A to 100 </ b> D in 160 and between the secondary battery modules 160 in the assembled battery system 161.

  On the other hand, when the phase change heat absorption means is arranged on the side surface portion 101b as in the present embodiment, the temperature of the side surface portion 101b can be kept relatively constant in the vicinity of the phase change temperature of the heat absorption means. Therefore, non-uniform temperature distribution between the secondary batteries 100A to 100D in the secondary battery module 160 and between the secondary battery modules 160 in the assembled battery system 161 can be suppressed.

(4) Also, by providing the heat radiation promoting means 137 thermally connected to the heat absorbing means 135, the heat absorbed by the heat absorbing means 135 can be quickly released to the outside, and the heat absorbing means 135 absorbs from the battery cell. The amount of heat possible can be increased. Thereby, the usage-amount of the thermal absorption means 135 for obtaining the same cooling effect can be reduced. Moreover, since heat can be more absorbed from the side surface of the battery cell, the non-uniform temperature distribution inside the electrode group can be further improved.
(5) By providing the heat radiation promoting means 137 thermally connected to the heat absorbing means 135, the heat absorbed by the heat absorbing means can be quickly released to the outside, and the heat generation that frequently repeats charging and discharging is short. Even in applications that are repeated over time, the temperature distribution inside the electrode group can be prevented from becoming uneven, and each battery cell can be efficiently cooled.
(6) Further, by holding the heat absorbing means on the side surface by the heat absorbing means holding member and the elastic member, even if the heat absorbing means expands, the thermal connection state between them can be maintained, and the cooling performance can be improved. Can be stabilized.

  Next, secondary batteries 100A to 100D and a secondary battery module 160 using the same according to a second embodiment of the present invention will be described with reference to FIGS. In addition, in 2nd Embodiment, it is the structure similar to 1st Embodiment except the point to which the heat conductive member was added inside the secondary batteries 100A-100D.

  FIG. 8 is a view in which the can 101 and the lid 102 are removed to show the inside of the battery cell of the second embodiment. This embodiment is the same as the first embodiment except that an internal heat conducting member 201 is provided between the first divided electrode group 170a and the second divided electrode group.

  As shown in FIG. 9, the internal heat conductive member 201 is configured in an “H” shape, and is located between the first divided electrode group 170 a and the second divided electrode group 170 b, that is, in the stacking direction of the electrode groups. A central surface portion 202 extending in the center position and a side surface portion 203 parallel to the side surface portion 101b of the secondary batteries 100A to 100D are provided.

The central surface portion 202 is in close contact with the inner side surfaces of the first divided electrode group 170a and the second divided electrode group 170b, and the side surface portion 203 is outside the first divided electrode group 170a and the second divided electrode group 170b. It is in close contact with the side.
Thereby, the internal heat conductive member 201 thermally connects the inside of the first divided electrode group 170a and the second divided electrode group 170b and the side surface portion 101b of the secondary batteries 100A to 100D. Further, the corners of the side surface portion 203 are chamfered so as not to damage the electrode group or the insulating sheet during assembly.

  The internal heat conducting member 201 has a function of transferring heat inside the first divided electrode group 170a and the second divided electrode group 170b to the side surface portion 101b of the secondary batteries 100A to 100D. For this reason, it is desirable that the internal heat conductive member 201 be made of a high heat conductive material. As such a material, for example, aluminum, copper, an aluminum alloy, or the like can be used.

  Moreover, although the center surface part 202 and the side part 203 may be comprised by another member, the center surface part 202 and the side part 203 need to be thermally connected.

  In the embodiment shown in FIG. 8 and FIG. 9, the electrode group is divided into two parts, a first divided electrode group 170a and a second divided electrode group 170b. A plurality of central surface portions 202 extending in position may be provided, and each may be configured to be thermally connected to the side surface portion 203 parallel to the side surface portion 101b of the secondary batteries 100A to 100D.

  Further, in the embodiment shown in FIGS. 8 and 9, the inside of the electrode and the side surface portion 101b of the secondary batteries 100A to 100D are thermally connected, but the inside of the electrode and the bottom surface portion of the secondary batteries 100A to 100D. The shape which connects thermally may be sufficient. In this case, the side surface portion 203 is not parallel to the side surface portion 101b of the secondary batteries 100A to 100D, but is configured in parallel with the bottom surface portion that spreads on the bottom surface of the secondary batteries 100A to 100D. However, in this case, the heat absorbing means 135 must be disposed on the bottom surface side of the secondary batteries 100A to 100D as in a third embodiment described later.

  According to the second embodiment, the following operational effects can be achieved in addition to the first embodiment.

  (7) By providing the internal heat conductive member 201 having the central surface portion 202 extending in the stacking direction of the electrode group and the side surface portion 101b of the secondary batteries 100A to 100D, or the side surface portion 203 parallel to the bottom surface portion. Therefore, the movement of heat from the inside of the electrode group where the temperature becomes high toward the side surface portion 101b or the bottom surface portion of the secondary batteries 100A to 100D is promoted. The maximum temperature of the electrode group can be lowered by absorbing this with the side surface portion 101b of the secondary batteries 100A to 100D or the heat absorbing means 135 provided on the bottom surface portion, and as a result, the secondary batteries 100A to 100D. Unevenness of the internal temperature distribution can be suppressed.

  Next, referring to FIG. 10, FIG. 11, FIG. 12, and FIG. 13b, a secondary battery module 160 according to a third embodiment of the present invention and an assembled battery system including a plurality of secondary battery modules 160 are provided. explain. In this embodiment, the same reference numerals as in the first embodiment are given the same reference numbers in the 300s instead of the 100s and the same numbers are used in the last two digits. Differences will be mainly described.

  FIG. 10 is a perspective view showing a configuration of a secondary battery module 360 including a plurality of secondary batteries according to the third embodiment of the present invention. FIG. 11 is a schematic cross-sectional view of the secondary battery module in FIG. 10 taken along the line AA. 12 is a front view of the assembled battery system 361 viewed from the front, and FIG. 13 is a side view of the assembled battery system 361 shown in FIG. 12 viewed from the side.

  As shown in FIGS. 12 and 13, the assembled battery system 361 is a substantially rectangular parallelepiped casing, and includes a shelf 362 for installing a plurality of secondary battery modules 360 at predetermined positions, and cooling air inside the casing. An intake portion 363 for taking in air, a cooling fan 364 for discharging air from the inside of the housing, and an assembled battery controller 366 for controlling a plurality of battery modules 360 and taking out predetermined power.

  In FIG. 12 and FIG. 13, the secondary battery module 360 is electrically connected to the secondary battery modules 360 or the assembled battery controller 366, as in the first embodiment, to the outside of the charged power. Or the secondary battery module 360 is charged from the outside.

  When the cooling fan 364 is activated during charging or discharging, the air taken into the housing from the opening 13 by the cooling fan 364 is a substantially duct-shaped space constituted by a shelf or the ceiling of the housing and the side of the housing. The secondary battery module 360 is cooled by flowing around the secondary battery module 360 disposed on the shelf 362. Here, the shelf 362 has an opening corresponding to the bottom of the secondary battery module 360. Therefore, the bottom surface of the secondary battery module 360 directly faces a substantially duct-shaped space formed below one shelf where the secondary battery module 360 is disposed. For this reason, the bottom surface of the secondary battery module 360 is also directly cooled by the air taken in by the cooling fan.

  As shown in FIG. 10, the secondary battery module 360 includes secondary batteries 300 </ b> A to 300 </ b> C. The secondary batteries 300A to 300C are the same as those in the first embodiment including the internal structure. The secondary batteries 300A to 300C each have a substantially rectangular parallelepiped shape, and are arranged side by side so that the side surface portions (side surface portions 101b in FIG. 4) in the first embodiment face each other. In the following, they are the same surfaces as the side surface portion 101a and the side surface portion 101b in the first embodiment.

  Secondary batteries 300 </ b> A to 300 </ b> C are each provided with a positive electrode terminal 341 and a negative electrode terminal 351, and are electrically connected by a bus bar 309. Further, the positive terminal 341 and the negative terminal 351 to which the bus bar 309 is not connected are electrically connected to the power controller 366 or another secondary battery module as in the first embodiment.

  The secondary battery module 360 includes a module bottom holding member 322 for holding the secondary batteries 300A to 300C from the bottom, and a module side holding member 324 for holding from the side face 101a side which is an open surface of the secondary batteries 300A to 300C. , A module end holding member 323 for holding the secondary batteries 300A and 300C from the outside, and a spacer 321 for keeping the secondary batteries 300A to 300C at a predetermined interval. The secondary batteries 300A to 300C The secondary battery module 360 is held at a predetermined position.

  The secondary battery controller 320 monitors the state of the secondary battery, and transmits or transmits a signal for controlling charge / discharge of the secondary battery module to the assembled battery controller 366 as necessary.

  As shown in FIGS. 10 and 11, the secondary battery module 360 includes a side surface side heat absorbing means 335 a on the side surface of the secondary batteries 300 </ b> A to 300 </ b> C, and a bottom surface side on the bottom surface side of the bottom holding member 322 of the secondary battery module 360. The heat absorption means 335b is provided.

  Further, the secondary battery module 360 includes a resilient member 338 between the heat absorption means 335a or between the heat absorption means 335a and the module end holding member 323, and the heat absorption means 335b is provided on the lower surface side of the heat absorption means 335b. The heat absorption means holding member 336a for holding from the side is provided.

  The heat absorbing means 335a or 335b is thermally connected to the side surface portion 101b of the secondary batteries 300A to 300C and the lower surface side of the bottom holding member 332, respectively, as in the first embodiment. In this embodiment, the heat absorbing means 335b is thermally connected to the lower surface side of the bottom holding member 332. However, the bottom holding member 332 is formed in a frame shape and the bottom surfaces of the secondary batteries 300A to 300C shown in FIG. It is also possible to configure so that the heat absorbing means 335b is in direct contact with the portion 101c.

  In FIG. 11, the electrode group 170 is stacked so as to extend in a direction perpendicular to the paper surface. Therefore, the electrode group 170 in which unit battery cells including the positive electrode plate 174, the negative electrode plate 175, and the separator 173 are stacked. , The extending direction of each plate-shaped battery cell is orthogonal to the surfaces of the side surface portion 101b and the bottom surface portion 101c of the secondary batteries 300A to 300C.

  Accordingly, since the heat absorbing means 335a and 335b are attached so as to be thermally connected to almost the entire surface of the side surface portion 101b and the bottom surface portion 101c, the side surface portion 101b and the bottom surface portion 101c are also almost uniformly absorbed by the heat absorbing means. It is close to the temperature of 335a, 335b.

  Therefore, the side surfaces 101b and the inner surfaces inside the bottom surface portion 101c of the secondary batteries 300A to 300C are also almost uniformly close to the temperature of the heat absorbing means 335a and 335b. For this reason, the extending | stretching direction of each plate-shaped battery cell which comprises the electrode group 170 faces the internal surface of the side part 101b and the bottom face part 101c on the substantially same conditions.

  As a result, the plate-shaped battery cells and the inner surfaces of the side surface portion 101b and the bottom surface portion 101c have substantially the same temperature gradient, and the heat generated in each battery cell has the same rate at the side surface portion 101b. Then, it flows to the inner surface of the bottom surface portion 101 c and further flows toward the heat absorbing means 135.

  For this reason, in the past, the heat generated easily in the vicinity of the center of the stacked battery cells as seen in the stacking direction of the battery cells, whereas in the case of this embodiment, the heat generated in each battery cell is at the same rate. Since the flow from the inner surface of the side surface portion 101b and the bottom surface portion 101c to the heat absorbing means 335a, 335b, the temperature distribution of the stacked battery cells can be made substantially uniform.

  The elastic member 338 maintains the contact state between the heat absorbing means 335a and the side surface portion 101b of the secondary batteries 300A to 300C even when the heat absorbing means 335a expands and contracts, like the elastic member 138 of the first embodiment. For this purpose, the secondary battery can be expanded and contracted in a direction perpendicular to the side surface portion 101 of the secondary battery.

  Next, the endothermic means holding member 336a is provided with an elastic spring structure 336b at the end, and holds the endothermic means 335b so as to press against the bottom holding member 332. That is, the heat absorbing means holding member 336a is a member having both functions of the elastic member 138 and the heat absorbing means holding member 136 in the first embodiment.

  The bottom holding member 332 holds the secondary batteries 300A to 300C from the bottom side, and at the same time has relatively high strength and thermal conductivity so that the heat absorbing means 335b can effectively absorb the heat generated in the secondary batteries 300A to 300C. It is desirable that the material is good. As such a material, for example, iron, aluminum, or an aluminum alloy can be used.

  Further, the heat absorbing means holding member 336a can be expanded and contracted in response to the expansion and contraction of the heat absorbing means 335b, and at the same time, in order to effectively dissipate the heat absorbed by the heat absorbing means 335b from the bottom surface side of the secondary battery module 360. It is desirable that the material has good thermal conductivity. For example, iron, aluminum, or an aluminum alloy can be used as such a material.

  The functions and desirable conditions of the heat absorbing means 335a, 335b are the same as those in the first embodiment. Further, the secondary batteries 300A to 300C constituting the secondary battery module 360 have the same configuration as the secondary battery in the first embodiment.

  According to the embodiment described above, the following operational effects can be obtained in addition to the effects (1), (2), and (3) in the first embodiment.

  (8) When discharging or charging is performed, heat is generated inside the electrode group 170. A part of this heat is released to the outside from the lid 102 and the terminals 141 and 151, and the rest can be passed through the insulating film 108. 101. The heat absorbing means 335b is arranged to be thermally connected to the bottom surface portion 101c of the secondary batteries 300A to 300C via the bottom holding member 332, and the heat generated in the battery cell is absorbed by the heat absorbing means 335b. Therefore, the bottom surfaces 101c of the secondary batteries 300A to 300C are maintained at a lower temperature than when the heat absorbing means 335b is not provided. Therefore, the heat generated in the electrode group 170 is more easily released from the bottom surface portion 101c to the outside of the secondary batteries 300A to 300C than the side surface portion 101a as compared with the case where the heat absorbing means 335b is not provided.

  Therefore, as in the case of the effect (1) of the first embodiment, as in the case where the endothermic means 335a is arranged on the side surface portion 101b of the secondary batteries 300A to 300C, the electrodes are suppressed while suppressing the nonuniformity of the internal temperature distribution of the electrode group 170. The group temperature can be lowered. Of course, if the heat is absorbed from both the side surface portion 101b and the bottom surface portion 101c, the temperature of the electrode group can be lowered while further suppressing the non-uniformity of the internal temperature distribution of the electrode group 170.

  (9) The heat absorbing means 335b is disposed on the bottom surface portion 101c of the secondary batteries 300A to 300C, and a portion corresponding to the bottom surface portion 101c of the secondary battery 360 is opened in the shelf 362 in the assembled battery system 361. The heat absorbed by the heat absorbing means 335b can be quickly released to the outside, and the amount of heat that the heat absorbing means 335b can absorb from the secondary batteries 300A to 300C can be increased. Thereby, the usage-amount of the heat absorption means 335b for obtaining the same cooling effect can be reduced. In addition, since heat can be more absorbed from the bottom surface portion 101 c of the secondary battery 360, it is possible to further suppress non-uniform temperature distribution inside the electrode group.

  (10) By disposing the heat absorbing means 335b on the bottom surface portion 101c of the secondary batteries 300A to 300C, and further opening the portion corresponding to the bottom surface portion 101c of the secondary battery in the shelf 362 in the assembled battery system 361, The heat absorbed by the heat-absorbing means 335b can be quickly released to the outside, and the temperature distribution inside the electrode group is increased evenly in applications where heat generation such as frequent charge / discharge is repeated in a short time. Secondary battery 300A-300C can be cooled without doing.

In the present embodiment, unlike the first embodiment, the heat dissipation means 335a provided on the side surface portion 101b of the secondary batteries 300A to 300C is not provided with the heat dissipation promotion means 137. Therefore, in this embodiment, the heat absorption means 335a provided on the side surface portion 101b of the secondary batteries 300A to 300C.
Finally, the heat absorbed at the end is radiated mainly from the side surface portion 101a which is the open surface of the secondary batteries 300A to 300C.

  However, since the side surface portion 101b of the secondary batteries 300A to 300C has heat absorption means, the heat generated inside the electrode group 170 is directed toward the side surface portion 101a that is an open surface that flows in the stacking direction of the electrode group. It flows in the extending direction of the plate-shaped battery cells of the electrode group 170 to reach the side surface portion 101b of the secondary batteries 300A to 300C, and then flows to the side surface portion 101a which is an open surface via the heat absorbing means 335a. .

  Therefore, even if the final heat radiation surface is the open side surface 101a, the heat absorption means 335a is provided on the side surface portion 101b of the secondary batteries 300A to 300C, so that the passage of heat inside the secondary batteries 300A to 300C. A path | route changes and the nonuniformity of the temperature distribution inside an electrode group can further be suppressed. That is, as in the first embodiment, functions and effects (1) and (2) can be obtained.

  The following modifications are also within the scope of the present invention, and one or a plurality of these modifications can be combined with the above-described embodiment.

  In Example 1 to Example 3 described above, as shown in FIG. 7, the electrode group 170 is manufactured by alternately laminating the positive electrode plate 174 and the negative electrode plate 175 alternately with the separator 173 interposed therebetween. On the other hand, as shown in FIG. 14, the electrode group 470 can be formed so that the positive electrode plate, the negative electrode plate, and the separator are attached in an elliptical shape or a circular shape, and this is hereinafter referred to as a wound electrode group.

  Next, the configuration of the wound electrode group will be described with reference to FIG. Here, portions having the same functions as those in the first embodiment are provided with reference numbers in the 400s instead of the 100s, and the last two digits are the same. Therefore, the description of the components having the same functions as those in the first embodiment is omitted.

  In the secondary battery 400 shown in FIG. 12, the wound electrode group 470 includes a pair of a positive electrode plate, a negative electrode plate, and a separator that are roughly elliptically or circularly wound to form an electrode group, and a positive electrode tab 478 at the end thereof. A negative electrode tab 479 is formed.

  The positive electrode tab 378 is electrically connected to the positive electrode current collector 480 and the positive electrode terminal 441. Although not shown, a negative electrode current collector is provided on the side facing the positive electrode current collector 480, and the negative electrode tab 479 is electrically connected to the negative electrode current collector and the negative electrode terminal 451.

  Also in the secondary battery 400 having such a wound electrode group, the same effect as that of the first embodiment can be obtained by providing the side surface 401b with heat absorbing means. That is, as shown in FIG. 14, also in the wound electrode group 470, the extending direction of the unit battery cell extends toward the side surface portion 401b. Although not shown in the figure, the heat absorbing means 135 is attached to the side surface portion 401b so as to be thermally connected.

  Therefore, in the unit battery cell including the positive electrode plate, the negative electrode plate, and the separator of the wound electrode group 470, the extending direction of each plate-shaped battery cell is orthogonal to the surface of the side surface portion 401b of the secondary battery 400. become. Since the heat absorbing means is attached to almost the entire surface of the side surface portion 401b so as to be thermally connected, the side surface portion 401b is also almost uniformly close to the temperature of the heat absorbing means.

  For this reason, the inner side surface which is the inner side of the side surface portion 401b of the secondary battery 400 is also almost uniformly close to the temperature of the heat absorbing means. For this reason, the extending | stretching direction of each plate-shaped battery cell which comprises the electrode group 470 faces the internal side surface of the side part 401b on the substantially same conditions.

  As a result, the plate-shaped battery cells and the inner surfaces of the side surface portion 101b and the bottom surface portion 101c have substantially the same temperature gradient, and the heat generated in each battery cell has the same rate at the side surface portion 101b. Then, it flows to the inner surface of the bottom surface portion 101 c and further flows toward the heat absorbing means 135.

  For this reason, in the past, the heat generated easily in the vicinity of the center of the stacked battery cells as seen in the stacking direction of the battery cells, whereas in the case of this embodiment, the heat generated in each battery cell is at the same rate. Since the heat flows from the inner side surface of the side surface portion 401b to the heat absorbing means, the temperature distribution of the stacked battery cells can be made substantially uniform.

  However, in the unit battery cell constituting the wound electrode group 470, the positive electrode between the side surface portion 401b and the electrode group 470 is compared with the unit battery cell having the electrode group 170 as in the first to third embodiments. Since the current collector 480 or a negative electrode current collector (not shown) is interposed, this becomes a thermal resistance, and the effect of disposing the heat absorbing means on the side surface portion 401b may be reduced. Therefore, the battery cell is preferably an electrode group in which a positive electrode plate, a negative electrode plate, and a separator are laminated in parallel.

  In the embodiment shown in Example 1, each of the secondary batteries 100A to 100D includes the individual heat absorption means 135 and the heat dissipation promotion means 137, but the four heat absorption means 135 may be integrated. In addition, the heat radiation promoting means 137 may be integrated. In this case, the number of parts is reduced.

  Furthermore, in the embodiment shown in Example 1, the heat radiation promoting means 137 is an enlarged heat transfer surface having irregularities, but the heat radiation promoting means 137 may use so-called water cooling in which a cooling refrigerant such as water is circulated. In this case, since the heat absorbed by the heat absorbing means 135 is radiated more efficiently, the amount of the heat absorbing means 135 used can be reduced as shown in the operational effect (4) in the embodiment shown in Example 1. it can. Similarly, as shown in the operational effect (5) in the embodiment shown in Example 1, it is possible to cool more effectively even in applications where heat generation such as frequent charge / discharge is repeated in a short time. .

  Finally, in the embodiment of the present invention, the heat absorbing means is held in a secondary battery or a secondary battery module. However, in a large-scale assembled battery system in which a plurality of secondary battery modules are combined, for example, the secondary battery module can be used as long as it is thermally connected between the secondary battery, the heat absorbing means, and the expanded heat transfer surface. In order to improve portability, the heat absorbing means or the expanded heat transfer surface can be separated from the secondary battery module and fixed as a separate component on the casing of the assembled battery system.

  The present invention is not limited to the various embodiments described above, and can be freely changed and improved without departing from the gist of the invention.

  100A to 100D ... secondary battery, 101 ... can, 101a ... side face, 101b ... side face, 101c ... bottom face, 102 ... lid, 103 ... gas discharge valve, 106 ... liquid injection part, 108 ... insulating film, 109 ... Bus bar, 120 ... battery cell controller, 121 ... spacer, 122 ... module bottom holding member, 123 ... module end holding member, 124 ... module side holding member, 135 ... heat absorption means, 136 ... heat absorption means holding member, 137 ... heat dissipation promotion Means: 138 ... bullet member, 141 ... positive electrode terminal, 142 ... sealing material, 151 ... negative electrode terminal, 160 ... secondary battery module, 161 ... assembled battery system, 162 ... shelf, 163 ... intake part, 164 ... cooling fan, 166 ... Battery controller, 168 ... Power extraction terminal, 170 ... Electrode group, 170a ... First divided electrode group, 170 ... 2nd electrode division group, 171 ... Positive electrode foil, 172 ... Negative electrode foil, 173 ... Separator, 174 ... Positive electrode plate, 175 ... Negative electrode plate, 176 ... Positive electrode layer, 177 ... Negative electrode layer, 178 ... Positive electrode tab, 179 ... Negative electrode tab, 180 ... Positive current collector, 190 ... Negative current collector, 201 ... Internal heat conduction member, 300A to 300C ... Secondary battery, 309 ... Bus bar, 320 ... Battery cell controller, 321 ... Spacer, 322 ... Bottom of module Holding member, 323 ... end holding member, ... 324 ... module side surface holding member, 335a ... heat absorption means, 335b ... heat absorption means, 336a ... heat absorption means holding member, 336b ... spring structure, 338 ... elastic member, 341 ... positive electrode terminal 351, negative electrode terminal, 360, secondary battery module, 361, assembled battery system, 362, shelf, 363, air intake, 364, cooling fan, 3, 66 ... Battery controller, 368 ... Electric power extraction terminal.

Claims (13)

An electrode group configured by laminating a plurality of unit battery cells having a separator interposed between a plate-like positive electrode plate and a negative electrode plate, a battery container containing the electrode group, and electrically connected to the electrode group; A secondary battery comprising a positive electrode terminal and a negative electrode terminal that are at least exposed to the outside of the battery container and can be electrically connected to the outside,
The heat absorption means is disposed outside the inner wall of the battery container facing the end in the extending direction of the unit battery cells constituting the electrode group so as to absorb the heat generated in the electrode group. Secondary battery. An electrode group configured by laminating a plurality of unit battery cells having a separator interposed between a plate-like positive electrode plate and a negative electrode plate, a battery container containing the electrode group, and electrically connected to the electrode group; A secondary battery comprising a positive electrode terminal and a negative electrode terminal that are at least exposed outside the battery container and can be electrically connected to the outside,
An endothermic device is disposed outside the inner wall of the battery container facing the extending direction of the unit battery cells perpendicular to the stacking direction of the unit battery cells constituting the electrode group to absorb heat generated by the electrode group. A secondary battery characterized by that. The secondary battery according to claim 2,
The battery container has a substantially rectangular parallelepiped can having a bottom wall portion having one end opened and two pairs of side wall portions, and a lid for sealing the opening, and the positive electrode terminal and the negative electrode terminal are attached to the lid. The electrode group is stacked in a plurality of unit battery cells so as to conform to the shape of the can, and is accommodated in the can, and is positioned in the extending direction of the unit battery cell perpendicular to the stacking direction of the unit battery cells. A secondary battery, wherein the heat absorbing means is provided so as to be thermally connected to at least one side wall. The secondary battery according to claim 2,
The battery container has a substantially rectangular parallelepiped can having a bottom wall portion having one end opened and two pairs of side wall portions, and a lid for sealing the opening, and the positive electrode terminal and the negative electrode terminal are attached to the lid. The electrode group is stacked in a plurality of unit battery cells so as to conform to the shape of the can, and is accommodated in the can, and is positioned in the extending direction of the unit battery cell perpendicular to the stacking direction of the unit battery cells. A secondary battery characterized in that the endothermic means is provided so as to be thermally connected to a bottom wall portion. The secondary battery according to any one of claims 1 to 4,
2. The secondary battery according to claim 1, wherein the endothermic means is a mixture containing a material that causes a thermal reaction accompanied by a phase change at a specific temperature. The secondary battery according to any one of claims 3 to 4,
The electrode group is divided into at least two in the stacking direction, and an internal heat conductive member made of a material having good heat conductivity is disposed in the divided portion, and the internal heat conductive member is arranged in the extending direction of the unit battery cell. A secondary battery, wherein the secondary battery extends to the vicinity of at least one side wall portion and flows heat generated in the electrode group to the heat absorbing means. The secondary battery according to claim 3,
The secondary battery is characterized in that the heat absorbing means is held outside the battery container by a heat absorbing means holding member capable of absorbing a displacement accompanying expansion and contraction of the heat absorbing means. The secondary battery according to claim 3,
A secondary battery, wherein heat dissipation means is thermally connected to the heat absorption means. The secondary battery according to claim 8,
The secondary battery according to claim 1, wherein the heat radiation promoting means is an enlarged heat transfer surface. A plurality of battery containers having a substantially rectangular parallelepiped can having a bottom wall portion having one end opened and two pairs of side wall portions, a positive electrode terminal sealing the opening, and a lid attached with a negative electrode terminal are arranged in series and arranged Connecting the positive terminal and the negative terminal of a plurality of battery containers in series,
A plurality of unit battery cells are stacked so as to conform to the shape of the can and the electrode group housed in the can is connected to the positive terminal and the negative terminal of the battery container,
An endothermic means is thermally connected to at least one of the side wall portion or the bottom wall portion of the can located in the extending direction of the unit battery cell perpendicular to the stacking direction of the unit battery cells constituting the electrode group. A secondary battery module characterized by being made. The secondary battery module according to claim 10,
The heat absorbing means is thermally connected to the other pair of side wall portions different from the pair of side wall portions facing each other of the battery containers arranged in series. Secondary battery module. A plurality of rechargeable battery modules, a plurality of shelves provided in the height direction, and a housing including a cooling fan for flowing air to the shelves;
A battery container mounted on the plurality of shelves and having a substantially rectangular parallelepiped can having a bottom wall portion having one end opened and two pairs of side wall portions, and a lid attached with a positive electrode terminal and a negative electrode terminal for sealing the opening. A plurality of unit battery cells stacked in line with the shape of the can and accommodated in the can. Is connected to the positive electrode terminal and the negative electrode terminal of the battery container, and the side wall portion of at least one of the cans positioned in the extending direction of the unit battery cells perpendicular to the stacking direction of the unit battery cells constituting the electrode group Or a secondary battery module in which an endothermic means is thermally connected to the bottom wall,
A bus bar that electrically connects the plurality of secondary battery modules, and an assembled battery controller that is provided in the housing and performs power control of the plurality of secondary battery modules for supplying predetermined power to the outside. An assembled battery system characterized by that. The assembled battery system according to claim 12,
The assembled battery system, wherein the cooling fan is attached to the housing so as to allow air to flow along the direction of the shelf.

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