JP2014029808A - Battery pack and battery pack module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack capable of suppressing temperature rise due to abnormal heat generation of a battery at a low cost.SOLUTION: A battery pack 10 includes a battery stack 11 that is constituted of a plurality of laminated and arranged batteries 11a, and heat radiation parts 12a and 12a that are provided between facing lamination surfaces 11b and 11b of adjacent batteries 11a and 11a in the battery stack 11 and in at least two spaces out of spaces outside the lamination surface 11b outside the battery 11a at both ends in the lamination direction of the battery stack 11, and at least two heat radiation parts 12a and 12a that are adjacent in the lamination direction are constituted of a sheet of thin plate like heat radiation member 12 that is obtained by performing coupling through a bending part 12b.

Description

  The present invention relates to a battery pack configured by stacking a plurality of unit cells and connecting them in series or in parallel.

  In recent years, lithium-ion batteries having high energy density have attracted attention as power sources for mobile devices, hybrid vehicles, and electric vehicles. In particular, in a vehicle application, a plurality of single cells (secondary batteries) are connected in series to form an assembled battery so as to obtain a large voltage. Usually, such an assembled battery is provided with a cooling structure in order to suppress an increase in battery temperature due to heat generation during use.

  Patent Document 1 discloses an assembled battery in which a plurality of stacked batteries are stacked and connected in series. In this assembled battery, a heat insulating member is provided between a heat radiating member that contacts both surfaces of each battery and a heat radiating member of an adjacent battery. The plurality of heat dissipating members are connected by a heat transfer member provided on the side surface of the assembled battery, and heat generated in the battery is transmitted from the heat dissipating member to the heat transfer member. The connected heat dissipating members are arranged for every two batteries, and the heat insulating member prevents heat from being transferred to adjacent batteries. With such a heat transfer structure, the heat generated in the battery is transmitted not to the periphery of the battery but to the battery at a distance.

JP 2011-238374 A

  The cooling structure in the assembled battery is generally configured to cope with heat generated by normal use. However, in a lithium ion battery, abnormal heat may be generated in the event of a failure or the like. When abnormal heat is generated, there is a risk of fire in the worst case unless the temperature rise of the abnormally heated battery is suppressed. However, when a specific unit cell in the assembled battery abnormally generates heat, heat is usually transmitted to the cooling structure only from the vicinity of the unit cell and dissipated. In this case, if the amount of generated heat is large, all of the generated heat cannot be transmitted to the cooling structure, and is stored inside the unit cell, and there is a possibility that the temperature increase of the unit cell that has abnormally generated heat cannot be suppressed.

  The heat transfer structure in the assembled battery disclosed in Patent Document 1 is a member in which a plurality of heat radiating members protrude vertically from one surface of the heat transfer member, and the member is made by casting or extrusion molding. The assembled battery is configured by using two of these members and sandwiching each of the stacked batteries so that the heat dissipating members of the respective members are alternately arranged. Therefore, even when abnormal heat is generated in a specific battery, the heat is transmitted to a battery at a distant place and dispersed throughout the assembled battery. Therefore, heat does not accumulate around the battery that has abnormally generated heat, and the temperature rise of the battery is suppressed. As described above, the heat transfer structure of the assembled battery disclosed in Patent Document 1 can cope with abnormal heat generation of the battery, but the structure is complicated, and as a result, there is a problem that the price increases. .

  In view of the above problems, an object of the present invention is to provide an assembled battery that can suppress an increase in temperature due to abnormal heat generation of the battery at low cost.

  In order to solve the above-described problems, the battery pack according to the present invention includes a battery stack composed of a plurality of unit cells arranged in a stacked manner, and a stack of opposing unit cells adjacent to each other in the battery stack. A heat dissipating part disposed in at least two spaces among the spaces outside the unit cell between the surfaces and outside the unit cell at both ends of the cell stack in the layer direction. The at least two adjacent heat radiating portions are configured by a single thin plate-shaped heat radiating member connected via a bent portion.

  With such a characteristic configuration, the thermal resistance between the plurality of heat radiating portions can be reduced, and the heat capacity of the entire heat radiating member can be maximally utilized to radiate heat. That is, the heat transmitted from the abnormally heated unit cell to the nearest heat radiating part is easily transmitted to the other heat radiating part via the bent part. As a result, it is possible to dissipate the heat generated by the abnormality to the plurality of heat dissipating portions and dissipate the heat from the entire heat dissipating member, and to suppress the temperature rise of the unit cell that has abnormally generated heat.

  In the battery pack according to the present invention, it is preferable that the heat dissipating part is disposed in the entire space.

  With such a configuration, since all the cells constituting the assembled battery are in contact with the heat radiating part, even if any unit battery generates abnormal heat, heat is transmitted to other heat radiating parts to dissipate heat. Heat can be dissipated from the entire member, and the temperature rise of the unit cell that has abnormally generated heat can be suppressed.

  In the assembled battery according to the present invention, it is preferable that the heat radiating member is constituted by connecting all of the heat radiating portions by the bent portion.

  With such a configuration, even if abnormal heating occurs in any of the cells that make up the assembled battery, it is transferred from the abnormally heated unit cell to the nearest heat radiating part, and heat is transmitted to all other heat radiating parts. It is possible to transmit heat from the entire heat radiating member, and it is possible to suppress an increase in the temperature of the unit cell that has abnormally generated heat.

  In the battery pack according to the present invention, it is preferable that the bent portion has a portion not in contact with the unit cell.

  With such a configuration, the bent portion can be elastically deformed by the gap between the portion of the bent portion that is not in contact with the unit cell and the unit cell, so that the inner side of the length in the width direction of the assembled battery including the bent portion When the assembled battery is inserted into the outer case having a short length in the width direction, the bent portion 12b is elastically deformed so that the bent portion can come into surface contact with the inner side of the outer case. Thus, the heat generated by the assembled battery can be efficiently transmitted to the exterior case and released to the outside.

  In the assembled battery according to the present invention, it is preferable that the battery pack includes a heat dissipation buffer disposed between the stacked surface and the heat dissipating part and in contact with both the stacked surface and the heat dissipating part.

  This configuration not only improves the heat dissipation from the unit cell, but also protects the unit cell because the heat dissipation buffer absorbs the vibration energy and impact energy when vibration or impact is applied from the outside. Can do. Moreover, since the heat-dissipation buffer material can absorb the volume change (expansion) by charging / discharging of a single cell, when one cell expands, it can prevent having a bad influence on another cell.

  In the battery pack according to the present invention, the heat-dissipating buffer material is stretched so as to be in contact with the entire bent portion, and is bent and stretched along a side surface parallel to the side surface of the unit cell facing the bent portion. It is preferable that the entire side surfaces on both sides of the battery stack are covered.

  With such a configuration, regardless of the direction of vibration or impact applied from the outside, the heat dissipation buffer material can absorb the vibration energy or impact energy to protect the unit cell.

It is a perspective view showing the schematic structure of the assembled battery which concerns on this embodiment. It is a top view showing schematic structure of an assembled battery. It is a perspective view showing schematic structure of a thermal radiation member. It is a perspective view showing schematic structure of a thermal radiation sponge. It is a perspective view showing schematic structure of an assembled battery module. It is a disassembled perspective view showing each component of an assembled battery module. It is a longitudinal cross-sectional view showing schematic structure of an assembled battery module.

1. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view illustrating a schematic configuration of a battery pack 10 according to the present embodiment. FIG. 2 is a plan view of the schematic configuration of the assembled battery 10 as viewed in the height direction. FIG. 3 is a perspective view illustrating a schematic configuration of the heat dissipation member 12 according to the present embodiment. The assembled battery 10 includes a battery stack 11, a heat radiating member 12, a heat radiating sponge 13 as a heat radiating buffer, and a flexible conductor 27.

  The battery stack 11 is formed by stacking seven flat unit cells (hereinafter referred to as unit cells) 11a and connecting them in series. The unit cell 11a is a lithium ion polymer secondary battery. Each unit cell 11a has a rectangular parallelepiped shape, and a positive electrode terminal P and a negative electrode terminal N protrude from an upper surface 11d perpendicular to the height direction. In the battery stack 11, the positive electrode terminal P of one unit cell 11a and the negative electrode terminal N of the adjacent unit cell 11a are arranged to face each other, and the opposite positive electrode terminal P and negative electrode terminal N are connected by copper bus bars 11f and 11g. By sandwiching and fastening with bolts, the battery stacks 11 are connected in series.

  Of the positive electrode terminal P and the negative electrode terminal N of the cell 11a, the positive electrode terminal P of the single cell 11a at one end of the single cells 11a arranged at both ends in the battery stack 11 is the positive electrode terminal PE at the end, and the single cell at the other end. The negative terminal N of the battery 11a is referred to as an end negative terminal NE. The terminals to be connected in series are all the positive terminals P and the negative terminals N except for the end positive terminal PE and the end negative terminal NE. Four holes are opened at equal intervals in each of the positive terminal P and the negative terminal N to be connected. The bus bar 11f is formed with four holes at locations corresponding to the four holes of the terminal, and the bus bar 11g is formed with a screw hole at the same location as the bus bar 11f. Then, the positive electrode terminal P and the negative electrode terminal N are sandwiched between the bus bars 11f and 11g, the bolts are inserted into the respective holes from the bus bar 11f side, and are fastened by the screw holes of the bus bar 11g. N is electrically connected.

  Similarly to the positive terminal P and the negative terminal N, four holes are formed at equal intervals in the end positive terminal PE and the end negative terminal NE. Then, one terminal of the flexible conductors 27 and 27 is brought into contact with the end positive terminal PE and the end negative terminal NE, respectively, and is further sandwiched between the bus bars 11f and 11g. After that, by inserting bolts into the respective holes from the bus bar 11f side and fastening with the screw holes of the bus bar 11g, the end positive terminal PE, the end negative terminal NE and the flexible conductors 27, 27 are electrically connected. Is done. The flexible conductor 27 is a conductor in which terminals are provided at both ends of a flat braided wire.

  In the present embodiment, the single battery 11a is a lithium ion polymer secondary battery, but is not limited to this, and other types of batteries may be used. In the present embodiment, the battery stack 11 is configured by stacking seven unit cells 11a. However, the present invention is not limited to this, and the number of stacks may be changed as appropriate according to the voltage required for the assembled battery 10. Is possible.

  As shown in FIG. 3, the heat radiating member 12 is made of a metal having a high thermal conductivity such as aluminum or copper in a plate shape with a thickness of 0.3 to 0.5 mm, for example. The heat radiating member 12 has a shape in which a rectangular thin plate is folded in a zigzag manner, and includes a heat radiating portion 12a and a bent portion 12b.

  As shown in FIGS. 1 and 2, the heat dissipating part 12 a includes a space in the heat dissipating member 12 where the stacked surfaces 11 b and 11 b perpendicular to the stacking direction of the adjacent unit cells 11 a of the battery stack 11 face each other and the stacking direction. It is a part arrange | positioned in the space of the outer side of the laminated surface 11b of the outer side of the cell 11a in both ends. The length in the width direction of the heat dissipating part is the same as the length in the width direction of the stacked surface 11b of the facing unit cell 11a, and the length in the height direction is the length in the height direction of the stacked surface 11b of the facing unit cell 11a. A little shorter than that.

  The bent portion 12b is a portion of the heat radiating member 12 that connects adjacent heat radiating portions 12a and 12a. The bent portion 12b has the same length in the height direction as the length in the height direction of the heat radiating portion 12a, and has a curved portion in a cross section perpendicular to the height direction (parallel to the stacking direction). That is, the bent portion 12b is not in contact with the side surface 11c of the unit cell 11a and is separated from the side surface 11c. When the bent portion 12b has a curved portion, the adhesion between the heat radiating portion 12a and the laminated surface 11b can be improved as compared with the case where the bent portion 12b has a structure bent with respect to the heat radiating portion 12a. In this embodiment, as shown in FIG. 2, the cross section perpendicular to the height direction of the bent portion 12b is semicircular, but the shape is not limited to this. As long as it has a portion that is not in contact with the side surface 11c, the bent portion 12b may be composed of a curved portion and a straight portion.

  Thus, in the assembled battery 10, a plurality of heat radiating portions 12 a and bent portions 12 b are formed by bending one metal thin plate (heat radiating member 12). Since it is not necessary to form by using a complicated method such as extrusion, an inexpensive heat radiation structure can be realized. Note that a single sheet metal sheet is not only a single sheet metal sheet that has no joints, but also a plurality of sheet metal plates that are bonded together at any location by screwing, welding, soldering, rivet bonding, or the like. And those that minimize the contact thermal resistance of the joints. When joining a plurality of metal materials, they may be the same material, or for example, the heat radiation member 12 may be configured by combining different types of materials such as aluminum and copper.

  In the present embodiment, all the heat radiating portions 12a and the bent portions 12b are formed by one heat radiating member 12, but the present invention is not limited to this configuration. For example, all the heat radiating portions 12 a and the bent portions 12 b may be configured by a plurality of heat radiating members 12.

  In the present embodiment, the heat radiating portion 12a is arranged in the space between all the laminated surfaces 11b and in the space outside the laminated surface 11b outside the unit cell 11a at both ends in the lamination direction. It is not limited to. For example, there may be a space between the stacked surfaces 11b where the heat radiating portion 12a does not exist, or the heat radiating portions 12a are only in the outer space of one of the stacked surfaces 11b outside the unit cells 11a at both ends in the stacking direction. You may make it the structure arrange | positioned. Moreover, you may make it the structure by which the heat radiating member 12 is not arrange | positioned in the space outside the lamination | stacking surface 11b of the outer side of the cell 11a in a lamination direction both ends. However, in these configurations, there is a possibility that the effect of suppressing the temperature rise of the unit cell 11a that has generated heat in the case of abnormal heat generation may be reduced.

  FIG. 4 is a perspective view illustrating a schematic configuration of the heat dissipating sponge 13. As shown in FIGS. 1 and 2, the heat dissipation sponge 13 is inserted between the laminated surface 11b on one side of the unit cell 11a and the heat dissipation portion 12a. The heat dissipating sponge 13 is made of, for example, a silicone rubber foam, and has a rectangular shape in the expanded state. This is bent so that the cross section has a substantially U-shape, thereby forming a first portion 13a, a second portion 13b, and a third portion 13c. The length of the heat dissipation sponge 13 in the height direction is substantially the same as the length of the heat dissipation portion 12a in the height direction.

  As shown in FIG. 2, in a state where the heat radiating sponge 13 is inserted between the unit cell 11a and the heat radiating portion 12a, the first portion 13a is in contact with the heat radiating portion 12a and the laminated surface 11b, and the second portion 13b. Is in contact with the bent portion 12b, and the third portion 13c is in contact with the side surface 11c. Thereby, the heat dissipation sponge 13 covers the three surfaces of the unit cell 11a. As shown in FIG. 2, in the adjacent unit cell 11a, since the bent portion 12b is on the opposite side surface 11c, the heat dissipating sponge 13 is used upside down. That is, one type of heat dissipating sponge 13 can be applied to the entire assembled battery 10.

  By using the heat dissipating sponge 13, not only the heat generated in the unit cells 11 a is transmitted in the stacking direction, but also the vibration energy and impact energy when the assembled cell 10 is subjected to vibration and impact are absorbed and the unit cell 11 a Can be protected. In addition, since the heat dissipation sponge 13 covers the three surfaces of the unit cell 11a and, if stacked, the entire four surfaces with the heat dissipation portion 12a interposed therebetween, the vibration energy and impact energy can be transferred regardless of the direction of vibration or impact applied from the outside. Can absorb and protect the cell. Furthermore, since the heat dissipating sponge 13 can absorb the volume change (expansion) due to charging / discharging of the unit cell 11a, it is possible to prevent the other unit cell 11a from being stressed when one unit cell 11a expands. it can.

  In the present embodiment, the heat dissipating sponge 13 is attached so as to be in contact with the laminated surface 11b on one side of the unit cell 11a. However, the present invention is not limited to this. Good. In that case, in order to make the length of the assembled battery 10 in the stacking direction the same, the thickness of the heat dissipation sponge 13 needs to be halved.

  The assembled battery 10 is assembled so as to be sandwiched between the heat radiating portions 12a, 12a of the heat radiating member 12 in a state where the heat radiating sponge 13 is wound around the unit cell 11a. No adhesive or the like is used for assembling the unit cell 11a, the heat dissipation sponge 13, and the heat dissipation member 12.

2. Structure of the assembled battery module Next, the assembled battery module 1 in which the assembled battery 10 is incorporated in the outer case 20 will be described. FIG. 5 is a perspective view illustrating a schematic configuration of the assembled battery module 1. FIG. 6 is an exploded perspective view showing each component of the assembled battery module 1. FIG. 7 is a longitudinal sectional view showing a schematic configuration of the assembled battery module 1. The assembled battery module 1 includes an assembled battery 10, an outer case 20, a terminal block 23, a bottom cushion 24, a side cushion 25, and an upper cushion 26.

  The outer case 20 has a rectangular parallelepiped outer shape and a hollow structure, and is made of a metal material having high thermal conductivity such as an aluminum alloy and having high strength. The exterior case 20 includes a case body 21 and a lid body 22. As shown in FIGS. 6 and 7, the case main body 21 has a recess 21 a for incorporating the assembled battery 10 at the center, and heat sinks 21 b for releasing heat generated by the assembled battery 10 to the outside on both sides. ing. The center of the lid body 22 is opened in a rectangular shape, and a terminal block 23 is attached thereto.

  A bottom cushion 24 is disposed at the bottom of the recess 21a. The bottom cushion 24 is a thin plate-like component that covers the entire bottom surface of the case body 21, and is made of a material having high shock absorption, for example, a foam of silicon rubber. The assembled battery 10 is placed on the bottom cushion 24. Since the length in the width direction of the assembled battery 10 including the bent portion 12b is configured to be slightly longer than the length in the width direction of the concave portion 21a, the bent portion 12b of the assembled battery 10 is elastically deformed and the heat sink of the case body 21 21b is in surface contact. Further, a side cushion 25 that contacts both the third portion 13c of the heat radiating sponge 13 and the heat sink 21b is inserted into the space between the third portion 13c of the heat radiating sponge 13 and the heat sink 21b. The side cushion 25 is made of a material having high shock absorption and high thermal conductivity, such as a foam of silicon rubber. By having such a structure, the heat generated in the assembled battery 10 can be efficiently and reliably transmitted to the heat sink 21b and discharged from the heat sink 21b to the outside.

  The rectangular parallelepiped upper cushions 26, 26, and 26 are arranged at three locations on the center and both ends of the upper surface 11d of the assembled battery 10 so as to be in contact with the upper surface 11d and the longitudinal direction thereof being parallel to the stacking direction. The upper cushion 26 is made of the same material as the bottom cushion 24. All the upper cushions 26 are fixed to the case body 21 by fixing means (not shown) such as screws and adhesion. Thereby, the assembled battery 10 is fixed in the case main body 21.

  The other terminals of the flexible conductors 27, 27 having one terminal connected to the end positive terminal PE and the end negative terminal NE of the assembled battery 10 are connected to the bottom terminals 23 c, 23 c of the terminal block 23. The terminal block 23 is obtained by providing two sets of insulated terminals on a base 23a formed of an insulator such as resin. The upper terminals 23b and 23b formed on the upper portion of the base 23a are electrically connected to the bottom terminals 23c and 23c formed on the bottom. With this structure, the discharge current of the assembled battery 10 can be taken out from the upper terminals 23b and 23b.

3. Release of heat generated in battery pack and suppression of temperature rise Next, heat release generated in battery pack 10 will be described. The heat generated when the assembled battery 10 is operating normally is not a large amount of heat, and any single battery 11a generates the same amount of heat. Therefore, the heat generated in each cell 11a is mainly applied to the heat radiating portion 12a in contact with the laminated surface 11b, the first portion 13a of the heat radiating sponge 13, and the third portion 13c in contact with the side surface 11c. Communicated.

  The heat transmitted to the heat radiating portion 12a is transmitted to the heat sink 21b through the bent portion 12b, and is released to the outside from the heat sink 21b. The heat transmitted to the first portion 13a is mainly transmitted to the heat radiating portion 12a rather than the second portion 13b, and then transmitted to the heat sink 21b through the bent portion 12b and released to the outside from the heat sink 21b. This is because the heat conductivity of the heat radiating member 12 is very high compared to the heat conductivity of the heat radiating sponge 13. The heat transferred to the third portion 13c is transferred to the side cushion 25 and released to the outside from the heat sink 21b. By transmitting heat in this way, the temperature rise of the assembled battery 10 is suppressed.

  When any one or a plurality of unit cells 11a abnormally generate heat, the heat is transmitted to a portion of the heat sink 21b near the unit cell 11a that has abnormally generated heat and radiated to the outside. However, in the assembled battery module 1 according to the present embodiment, heat is not only radiated from the location, but is transmitted not only to the heat radiating portion 12a in the vicinity of the abnormally heated unit cell 11a but also to the heat radiating portion 12a in the distance. Heat can be dissipated from the entire heat sink 21b.

  This is because all the heat radiating portions 12a and the bent portions 12b are formed by one heat radiating member 12. With this structure, the thermal resistance between the heat radiating portions 12a can be reduced, and the heat capacity of the heat radiating member 12 as a whole can be utilized to the maximum. Therefore, the heat transferred from the unit cell 11a that has abnormally heated to the nearest heat radiating part 12a is easily transferred to the other heat radiating part 12a via the bent part 12b. As a result, heat can be distributed to all the heat radiating portions 12a, and heat can be radiated from a location near the distant heat radiating portion 12a in the heat sink 21b. Needless to say, heat is dissipated from the heat sink 21b even during the transmission because each bent portion 12b in the middle of the transmission is in contact with the heat sink 21b while the heat is transmitted through the heat radiating member 12.

  With this structure, heat due to abnormal heat generation can be dispersed throughout the assembled battery 10, and heat can be dissipated from the entire heat sink 21b. As a result, the heat dissipation efficiency from the heat sink 21b is increased, and the temperature increase of the unit cell 11a that has abnormally generated heat can be suppressed.

4). Vibration and impact resistance of the assembled battery module The assembled battery 10 has the bent portion 12b in contact with the heat sink 21b, the upper surface 11d on the upper cushion 26, the bottom surface 11e on the bottom cushion 24, and the side surface 11c on the side cushion 25, respectively. Covered. Further, the laminated surface 11b is covered with a heat radiating sponge 13 and a heat radiating portion 12a disposed between the individual cells 11a. That is, the assembled battery 10 is not in direct contact with the outer case 20 in a state of being incorporated in the assembled battery module 1. Furthermore, as shown in FIG. 6, the flexible conductors 27 are connected in a loose state between the end positive terminal PE and the bottom terminal 23c and between the end negative terminal NE and the bottom terminal 23c.

  Accordingly, even when vibration or impact is applied to the assembled battery module 1 from the outside, the heat sink 21b is deformed, the bottom cushion 24, the side cushion 25, the upper cushion 26, the bent portion 12b, the heat dissipation sponge 13, the flexible conductor 27, 27 and the like are deformed to absorb vibrations and shocks and attenuate the vibrations and shocks transmitted to the assembled battery 10. Thereby, the assembled battery 10 can be protected against vibration and impact from the outside.

  The present invention can be used for an assembled battery in which a plurality of batteries are stacked and connected in series or in parallel.

DESCRIPTION OF SYMBOLS 10 Assembly battery 11 Battery laminated body 11a Cell 11b Laminated surface 11c Side surface 12 Heat radiation member 12a Heat radiation part 12b Bending part 13 Heat radiation sponge (heat radiation buffer material)

The present invention relates to an assembled battery configured by stacking a plurality of unit cells and connecting them in series or in parallel, and an assembled battery module in which the assembled battery is incorporated in an outer case .

  In recent years, lithium-ion batteries having high energy density have attracted attention as power sources for mobile devices, hybrid vehicles, and electric vehicles. In particular, in a vehicle application, a plurality of single cells (secondary batteries) are connected in series to form an assembled battery so as to obtain a large voltage. Usually, such an assembled battery is provided with a cooling structure in order to suppress an increase in battery temperature due to heat generation during use.

  Patent Document 1 discloses an assembled battery in which a plurality of stacked batteries are stacked and connected in series. In this assembled battery, a heat insulating member is provided between a heat radiating member that contacts both surfaces of each battery and a heat radiating member of an adjacent battery. The plurality of heat dissipating members are connected by a heat transfer member provided on the side surface of the assembled battery, and heat generated in the battery is transmitted from the heat dissipating member to the heat transfer member. The connected heat dissipating members are arranged for every two batteries, and the heat insulating member prevents heat from being transferred to adjacent batteries. With such a heat transfer structure, the heat generated in the battery is transmitted not to the periphery of the battery but to the battery at a distance.

JP 2011-238374 A

  The cooling structure in the assembled battery is generally configured to cope with heat generated by normal use. However, in a lithium ion battery, abnormal heat may be generated in the event of a failure or the like. When abnormal heat is generated, there is a risk of fire in the worst case unless the temperature rise of the abnormally heated battery is suppressed. However, when a specific unit cell in the assembled battery abnormally generates heat, heat is usually transmitted to the cooling structure only from the vicinity of the unit cell and dissipated. In this case, if the amount of generated heat is large, all of the generated heat cannot be transmitted to the cooling structure, and is stored inside the unit cell, and there is a possibility that the temperature increase of the unit cell that has abnormally generated heat cannot be suppressed.

  The heat transfer structure in the assembled battery disclosed in Patent Document 1 is a member in which a plurality of heat radiating members protrude vertically from one surface of the heat transfer member, and the member is made by casting or extrusion molding. The assembled battery is configured by using two of these members and sandwiching each of the stacked batteries so that the heat dissipating members of the respective members are alternately arranged. Therefore, even when abnormal heat is generated in a specific battery, the heat is transmitted to a battery at a distant place and dispersed throughout the assembled battery. Therefore, heat does not accumulate around the battery that has abnormally generated heat, and the temperature rise of the battery is suppressed. As described above, the heat transfer structure of the assembled battery disclosed in Patent Document 1 can cope with abnormal heat generation of the battery, but the structure is complicated, and as a result, there is a problem that the price increases. .

In view of the above problems, an object of the present invention is to provide an assembled battery that can suppress an increase in temperature due to abnormal heat generation of the battery and an assembled battery module that incorporates the assembled battery in an exterior case at low cost.

In order to solve the above-described problems, the battery pack according to the present invention includes a battery stack composed of a plurality of unit cells arranged in a stacked manner, and a stack of opposing unit cells adjacent to each other in the battery stack. A heat dissipating part disposed in at least two spaces among the spaces outside the unit cell between the surfaces and outside the unit cell at both ends of the cell stack in the layer direction. The at least two adjacent heat radiating portions are constituted by a single thin plate-shaped heat radiating member connected via a bent portion, and the bent portion has a portion not in contact with the unit cell. The portion is capable of elastic deformation with respect to an external force applied in a direction toward the unit cell .

With such a characteristic configuration, the thermal resistance between the plurality of heat radiating portions can be reduced, and the heat capacity of the entire heat radiating member can be maximally utilized to radiate heat. That is, the heat transmitted from the abnormally heated unit cell to the nearest heat radiating part is easily transmitted to the other heat radiating part via the bent part. As a result, it is possible to dissipate the heat generated by the abnormality to the plurality of heat dissipating portions and dissipate the heat from the entire heat dissipating member, and to suppress the temperature rise of the unit cell that has abnormally generated heat. In addition, with such a configuration, the bent portion can be elastically deformed by the gap between the cell and the portion of the bent portion that is not in contact with the unit cell. For example, in the width direction of the assembled battery including the bent portion, When the assembled battery is inserted into an exterior case whose length in the width direction inside is shorter than the length, the bent portion is elastically deformed and the bent portion can be brought into surface contact with the inner side of the outer case. Thus, the heat generated by the assembled battery can be efficiently transmitted to the exterior case and released to the outside.

In order to solve the above-described problem, another feature of the assembled battery according to the present invention is that a battery stack composed of a plurality of unit cells arranged in a stacked manner, and the opposed unit cells adjacent to each other in the battery stack. A heat dissipating portion disposed in each of at least two spaces among the spaces outside the stacking surfaces outside the unit cells between the stacking surfaces and at both ends in the stacking direction of the battery stack. The at least two heat dissipating parts adjacent to each other in a direction are configured by a single thin plate heat dissipating member connected via a bent part, and the unit cell has a rectangular parallelepiped shape, and the stacked surface has the unit cell. The two surfaces having the largest area among the six surfaces constituting, and are disposed between the laminated surface and the heat radiating portion, and are generated in the unit cell by contacting both the laminated surface and the heat radiating portion. Heat to the laminated surface It lies in that it includes a radiator buffer material for buffering the vibration and the shock absorbing their energy when vibration or shock is externally applied with dissipating is transmitted to the heat radiating portion.

With such a characteristic configuration, the thermal resistance between the plurality of heat radiating portions can be reduced, and the heat capacity of the entire heat radiating member can be maximally utilized to radiate heat. That is, the heat transmitted from the abnormally heated unit cell to the nearest heat radiating part is easily transmitted to the other heat radiating part via the bent part. As a result, it is possible to dissipate the heat generated by the abnormality to the plurality of heat dissipating portions and dissipate the heat from the entire heat dissipating member, and to suppress the temperature rise of the unit cell that has abnormally generated heat. In addition, this configuration not only enhances the heat dissipation from the unit cell, but also protects the unit cell because the heat dissipation buffer absorbs vibration energy and impact energy when vibration or impact is applied from the outside. can do. Moreover, since the heat-dissipation buffer material can absorb the volume change (expansion) by charging / discharging of a single cell, when one cell expands, it can prevent having a bad influence on another cell.

In the battery pack according to the present invention, the heat-dissipating buffer material is stretched so as to be in contact with the entire bent portion, and is bent and stretched along a side surface parallel to the side surface of the unit cell facing the bent portion. It is preferable that the entire side surfaces on both sides of the battery stack are covered.

With such a configuration, regardless of the direction of vibration or impact applied from the outside, the heat dissipation buffer material can absorb the vibration energy or impact energy to protect the unit cell.

In the battery pack according to the present invention, it is preferable that the heat dissipating part is disposed in the entire space.

With such a configuration, since all the cells constituting the assembled battery are in contact with the heat radiating part, even if any unit battery generates abnormal heat, heat is transmitted to other heat radiating parts to dissipate heat. Heat can be dissipated from the entire member, and the temperature rise of the unit cell that has abnormally generated heat can be suppressed.

In the assembled battery according to the present invention, it is preferable that the heat radiating member is constituted by connecting all of the heat radiating portions by the bent portion.

With such a configuration, even if abnormal heating occurs in any of the cells that make up the assembled battery, it is transferred from the abnormally heated unit cell to the nearest heat radiating part, and heat is transmitted to all other heat radiating parts. It is possible to transmit heat from the entire heat radiating member, and it is possible to suppress an increase in the temperature of the unit cell that has abnormally generated heat.

A characteristic configuration of the assembled battery module according to the present invention includes the above assembled battery and an exterior case incorporating the assembled battery, and the length of the assembled battery including the bent portion in the width direction is the inside of the exterior case. It is longer than the length in the width direction, and the bent portion is in surface contact with the inside of the outer case while being elastically deformed.

As described above, if the bent portion is elastically deformed and has a characteristic configuration that makes surface contact with the inside of the exterior case, the heat generated by the assembled battery can be efficiently transmitted to the exterior case and discharged to the outside.

It is a perspective view showing the schematic structure of the assembled battery which concerns on this embodiment. It is a top view showing schematic structure of an assembled battery. It is a perspective view showing schematic structure of a thermal radiation member. It is a perspective view showing schematic structure of a thermal radiation sponge. It is a perspective view showing schematic structure of an assembled battery module. It is a disassembled perspective view showing each component of an assembled battery module. It is a longitudinal cross-sectional view showing schematic structure of an assembled battery module.

1. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view illustrating a schematic configuration of a battery pack 10 according to the present embodiment. FIG. 2 is a plan view of the schematic configuration of the assembled battery 10 as viewed in the height direction. FIG. 3 is a perspective view illustrating a schematic configuration of the heat dissipation member 12 according to the present embodiment. The assembled battery 10 includes a battery stack 11, a heat radiating member 12, a heat radiating sponge 13 as a heat radiating buffer, and a flexible conductor 27.

  The battery stack 11 is formed by stacking seven flat unit cells (hereinafter referred to as unit cells) 11a and connecting them in series. The unit cell 11a is a lithium ion polymer secondary battery. Each unit cell 11a has a rectangular parallelepiped shape, and a positive electrode terminal P and a negative electrode terminal N protrude from an upper surface 11d perpendicular to the height direction. In the battery stack 11, the positive electrode terminal P of one unit cell 11a and the negative electrode terminal N of the adjacent unit cell 11a are arranged to face each other, and the opposite positive electrode terminal P and negative electrode terminal N are connected by copper bus bars 11f and 11g. By sandwiching and fastening with bolts, the battery stacks 11 are connected in series.

  Of the positive electrode terminal P and the negative electrode terminal N of the cell 11a, the positive electrode terminal P of the single cell 11a at one end of the single cells 11a arranged at both ends in the battery stack 11 is the positive electrode terminal PE at the end, and the single cell at the other end. The negative terminal N of the battery 11a is referred to as an end negative terminal NE. The terminals to be connected in series are all the positive terminals P and the negative terminals N except for the end positive terminal PE and the end negative terminal NE. Four holes are opened at equal intervals in each of the positive terminal P and the negative terminal N to be connected. The bus bar 11f is formed with four holes at locations corresponding to the four holes of the terminal, and the bus bar 11g is formed with a screw hole at the same location as the bus bar 11f. Then, the positive electrode terminal P and the negative electrode terminal N are sandwiched between the bus bars 11f and 11g, the bolts are inserted into the respective holes from the bus bar 11f side, and are fastened by the screw holes of the bus bar 11g. N is electrically connected.

  Similarly to the positive terminal P and the negative terminal N, four holes are formed at equal intervals in the end positive terminal PE and the end negative terminal NE. Then, one terminal of the flexible conductors 27 and 27 is brought into contact with the end positive terminal PE and the end negative terminal NE, respectively, and is further sandwiched between the bus bars 11f and 11g. After that, by inserting bolts into the respective holes from the bus bar 11f side and fastening with the screw holes of the bus bar 11g, the end positive terminal PE, the end negative terminal NE and the flexible conductors 27, 27 are electrically connected. Is done. The flexible conductor 27 is a conductor in which terminals are provided at both ends of a flat braided wire.

  In the present embodiment, the single battery 11a is a lithium ion polymer secondary battery, but is not limited to this, and other types of batteries may be used. In the present embodiment, the battery stack 11 is configured by stacking seven unit cells 11a. However, the present invention is not limited to this, and the number of stacks may be changed as appropriate according to the voltage required for the assembled battery 10. Is possible.

  As shown in FIG. 3, the heat radiating member 12 is made of a metal having a high thermal conductivity such as aluminum or copper in a plate shape with a thickness of 0.3 to 0.5 mm, for example. The heat radiating member 12 has a shape in which a rectangular thin plate is folded in a zigzag manner, and includes a heat radiating portion 12a and a bent portion 12b.

  As shown in FIGS. 1 and 2, the heat dissipating part 12 a includes a space in the heat dissipating member 12 where the stacked surfaces 11 b and 11 b perpendicular to the stacking direction of the adjacent unit cells 11 a of the battery stack 11 face each other and the stacking direction. It is a part arrange | positioned in the space of the outer side of the laminated surface 11b of the outer side of the cell 11a in both ends. The length in the width direction of the heat dissipating part is the same as the length in the width direction of the stacked surface 11b of the facing unit cell 11a, and the length in the height direction is the length in the height direction of the stacked surface 11b of the facing unit cell 11a. A little shorter than that.

  The bent portion 12b is a portion of the heat radiating member 12 that connects adjacent heat radiating portions 12a and 12a. The bent portion 12b has the same length in the height direction as the length in the height direction of the heat radiating portion 12a, and has a curved portion in a cross section perpendicular to the height direction (parallel to the stacking direction). That is, the bent portion 12b is not in contact with the side surface 11c of the unit cell 11a and is separated from the side surface 11c. When the bent portion 12b has a curved portion, the adhesion between the heat radiating portion 12a and the laminated surface 11b can be improved as compared with the case where the bent portion 12b has a structure bent with respect to the heat radiating portion 12a. In this embodiment, as shown in FIG. 2, the cross section perpendicular to the height direction of the bent portion 12b is semicircular, but the shape is not limited to this. As long as it has a portion that is not in contact with the side surface 11c, the bent portion 12b may be composed of a curved portion and a straight portion.

  Thus, in the assembled battery 10, a plurality of heat radiating portions 12 a and bent portions 12 b are formed by bending one metal thin plate (heat radiating member 12). Since it is not necessary to form by using a complicated method such as extrusion, an inexpensive heat radiation structure can be realized. Note that a single sheet metal sheet is not only a single sheet metal sheet that has no joints, but also a plurality of sheet metal plates that are bonded together at any location by screwing, welding, soldering, rivet bonding, or the like. And those that minimize the contact thermal resistance of the joints. When joining a plurality of metal materials, they may be the same material, or for example, the heat radiation member 12 may be configured by combining different types of materials such as aluminum and copper.

  In the present embodiment, all the heat radiating portions 12a and the bent portions 12b are formed by one heat radiating member 12, but the present invention is not limited to this configuration. For example, all the heat radiating portions 12 a and the bent portions 12 b may be configured by a plurality of heat radiating members 12.

  In the present embodiment, the heat radiating portion 12a is arranged in the space between all the laminated surfaces 11b and in the space outside the laminated surface 11b outside the unit cell 11a at both ends in the lamination direction. It is not limited to. For example, there may be a space between the stacked surfaces 11b where the heat radiating portion 12a does not exist, or the heat radiating portions 12a are only in the outer space of one of the stacked surfaces 11b outside the unit cells 11a at both ends in the stacking direction. You may make it the structure arrange | positioned. Moreover, you may make it the structure by which the heat radiating member 12 is not arrange | positioned in the space outside the lamination | stacking surface 11b of the outer side of the cell 11a in a lamination direction both ends. However, in these configurations, there is a possibility that the effect of suppressing the temperature rise of the unit cell 11a that has generated heat in the case of abnormal heat generation may be reduced.

  FIG. 4 is a perspective view illustrating a schematic configuration of the heat dissipating sponge 13. As shown in FIGS. 1 and 2, the heat dissipation sponge 13 is inserted between the laminated surface 11b on one side of the unit cell 11a and the heat dissipation portion 12a. The heat dissipating sponge 13 is made of, for example, a silicone rubber foam, and has a rectangular shape in the expanded state. This is bent so that the cross section has a substantially U-shape, thereby forming a first portion 13a, a second portion 13b, and a third portion 13c. The length of the heat dissipation sponge 13 in the height direction is substantially the same as the length of the heat dissipation portion 12a in the height direction.

  As shown in FIG. 2, in a state where the heat radiating sponge 13 is inserted between the unit cell 11a and the heat radiating portion 12a, the first portion 13a is in contact with the heat radiating portion 12a and the laminated surface 11b, and the second portion 13b. Is in contact with the bent portion 12b, and the third portion 13c is in contact with the side surface 11c. Thereby, the heat dissipation sponge 13 covers the three surfaces of the unit cell 11a. As shown in FIG. 2, in the adjacent unit cell 11a, since the bent portion 12b is on the opposite side surface 11c, the heat dissipating sponge 13 is used upside down. That is, one type of heat dissipating sponge 13 can be applied to the entire assembled battery 10.

  By using the heat dissipating sponge 13, not only the heat generated in the unit cells 11 a is transmitted in the stacking direction, but also the vibration energy and impact energy when the assembled cell 10 is subjected to vibration and impact are absorbed and the unit cell 11 a Can be protected. In addition, since the heat dissipation sponge 13 covers the three surfaces of the unit cell 11a and, if stacked, the entire four surfaces with the heat dissipation portion 12a interposed therebetween, the vibration energy and impact energy can be transferred regardless of the direction of vibration or impact applied from the outside. Can absorb and protect the cell. Furthermore, since the heat dissipating sponge 13 can absorb the volume change (expansion) due to charging / discharging of the unit cell 11a, it is possible to prevent the other unit cell 11a from being stressed when one unit cell 11a expands. it can.

  In the present embodiment, the heat dissipating sponge 13 is attached so as to be in contact with the laminated surface 11b on one side of the unit cell 11a. However, the present invention is not limited to this. Good. In that case, in order to make the length of the assembled battery 10 in the stacking direction the same, the thickness of the heat dissipation sponge 13 needs to be halved.

  The assembled battery 10 is assembled so as to be sandwiched between the heat radiating portions 12a, 12a of the heat radiating member 12 in a state where the heat radiating sponge 13 is wound around the unit cell 11a. No adhesive or the like is used for assembling the unit cell 11a, the heat dissipation sponge 13, and the heat dissipation member 12.

2. Structure of the assembled battery module Next, the assembled battery module 1 in which the assembled battery 10 is incorporated in the outer case 20 will be described. FIG. 5 is a perspective view illustrating a schematic configuration of the assembled battery module 1. FIG. 6 is an exploded perspective view showing each component of the assembled battery module 1. FIG. 7 is a longitudinal sectional view showing a schematic configuration of the assembled battery module 1. The assembled battery module 1 includes an assembled battery 10, an outer case 20, a terminal block 23, a bottom cushion 24, a side cushion 25, and an upper cushion 26.

  The outer case 20 has a rectangular parallelepiped outer shape and a hollow structure, and is made of a metal material having high thermal conductivity such as an aluminum alloy and having high strength. The exterior case 20 includes a case body 21 and a lid body 22. As shown in FIGS. 6 and 7, the case main body 21 has a recess 21 a for incorporating the assembled battery 10 at the center, and heat sinks 21 b for releasing heat generated by the assembled battery 10 to the outside on both sides. ing. The center of the lid body 22 is opened in a rectangular shape, and a terminal block 23 is attached thereto.

  A bottom cushion 24 is disposed at the bottom of the recess 21a. The bottom cushion 24 is a thin plate-like component that covers the entire bottom surface of the case body 21, and is made of a material having high shock absorption, for example, a foam of silicon rubber. The assembled battery 10 is placed on the bottom cushion 24. Since the length in the width direction of the assembled battery 10 including the bent portion 12b is configured to be slightly longer than the length in the width direction of the concave portion 21a, the bent portion 12b of the assembled battery 10 is elastically deformed and the heat sink of the case body 21 21b is in surface contact. Further, a side cushion 25 that contacts both the third portion 13c of the heat radiating sponge 13 and the heat sink 21b is inserted into the space between the third portion 13c of the heat radiating sponge 13 and the heat sink 21b. The side cushion 25 is made of a material having high shock absorption and high thermal conductivity, such as a foam of silicon rubber. By having such a structure, the heat generated in the assembled battery 10 can be efficiently and reliably transmitted to the heat sink 21b and discharged from the heat sink 21b to the outside.

  The rectangular parallelepiped upper cushions 26, 26, and 26 are arranged at three locations on the center and both ends of the upper surface 11d of the assembled battery 10 so as to be in contact with the upper surface 11d and the longitudinal direction thereof being parallel to the stacking direction. The upper cushion 26 is made of the same material as the bottom cushion 24. All the upper cushions 26 are fixed to the case body 21 by fixing means (not shown) such as screws and adhesion. Thereby, the assembled battery 10 is fixed in the case main body 21.

  The other terminals of the flexible conductors 27, 27 having one terminal connected to the end positive terminal PE and the end negative terminal NE of the assembled battery 10 are connected to the bottom terminals 23 c, 23 c of the terminal block 23. The terminal block 23 is obtained by providing two sets of insulated terminals on a base 23a formed of an insulator such as resin. The upper terminals 23b and 23b formed on the upper portion of the base 23a are electrically connected to the bottom terminals 23c and 23c formed on the bottom. With this structure, the discharge current of the assembled battery 10 can be taken out from the upper terminals 23b and 23b.

3. Release of heat generated in battery pack and suppression of temperature rise Next, heat release generated in battery pack 10 will be described. The heat generated when the assembled battery 10 is operating normally is not a large amount of heat, and any single battery 11a generates the same amount of heat. Therefore, the heat generated in each cell 11a is mainly applied to the heat radiating portion 12a in contact with the laminated surface 11b, the first portion 13a of the heat radiating sponge 13, and the third portion 13c in contact with the side surface 11c. Communicated.

  The heat transmitted to the heat radiating portion 12a is transmitted to the heat sink 21b through the bent portion 12b, and is released to the outside from the heat sink 21b. The heat transmitted to the first portion 13a is mainly transmitted to the heat radiating portion 12a rather than the second portion 13b, and then transmitted to the heat sink 21b through the bent portion 12b and released to the outside from the heat sink 21b. This is because the heat conductivity of the heat radiating member 12 is very high compared to the heat conductivity of the heat radiating sponge 13. The heat transferred to the third portion 13c is transferred to the side cushion 25 and released to the outside from the heat sink 21b. By transmitting heat in this way, the temperature rise of the assembled battery 10 is suppressed.

  When any one or a plurality of unit cells 11a abnormally generate heat, the heat is transmitted to a portion of the heat sink 21b near the unit cell 11a that has abnormally generated heat and radiated to the outside. However, in the assembled battery module 1 according to the present embodiment, heat is not only radiated from the location, but is transmitted not only to the heat radiating portion 12a in the vicinity of the abnormally heated unit cell 11a but also to the heat radiating portion 12a in the distance. Heat can be dissipated from the entire heat sink 21b.

  This is because all the heat radiating portions 12a and the bent portions 12b are formed by one heat radiating member 12. With this structure, the thermal resistance between the heat radiating portions 12a can be reduced, and the heat capacity of the heat radiating member 12 as a whole can be utilized to the maximum. Therefore, the heat transferred from the unit cell 11a that has abnormally heated to the nearest heat radiating part 12a is easily transferred to the other heat radiating part 12a via the bent part 12b. As a result, heat can be distributed to all the heat radiating portions 12a, and heat can be radiated from a location near the distant heat radiating portion 12a in the heat sink 21b. Needless to say, heat is dissipated from the heat sink 21b even during the transmission because each bent portion 12b in the middle of the transmission is in contact with the heat sink 21b while the heat is transmitted through the heat radiating member 12.

  With this structure, heat due to abnormal heat generation can be dispersed throughout the assembled battery 10, and heat can be dissipated from the entire heat sink 21b. As a result, the heat dissipation efficiency from the heat sink 21b is increased, and the temperature increase of the unit cell 11a that has abnormally generated heat can be suppressed.

4). Vibration and impact resistance of the battery module 10 In the battery pack 10, the bent portion 12b is in contact with the heat sink 21b, the top surface 11d is on the top cushion 26, the bottom surface 11e is on the bottom cushion 24, and the side surface 11c is on the side cushion 25. Covered. Further, the laminated surface 11b is covered with a heat radiating sponge 13 and a heat radiating portion 12a disposed between the individual cells 11a. That is, the assembled battery 10 is not in direct contact with the outer case 20 in a state of being incorporated in the assembled battery module 1. Furthermore, as shown in FIG. 6, the flexible conductors 27 are connected in a loose state between the end positive terminal PE and the bottom terminal 23c and between the end negative terminal NE and the bottom terminal 23c.

  Accordingly, even when vibration or impact is applied to the assembled battery module 1 from the outside, the heat sink 21b is deformed, the bottom cushion 24, the side cushion 25, the upper cushion 26, the bent portion 12b, the heat dissipation sponge 13, the flexible conductor 27, 27 and the like are deformed to absorb vibrations and shocks and attenuate the vibrations and shocks transmitted to the assembled battery 10. Thereby, the assembled battery 10 can be protected against vibration and impact from the outside.

The present invention can be used for an assembled battery configured by stacking a plurality of batteries and connecting them in series or in parallel, and an assembled battery module in which the assembled battery is incorporated in an exterior case .

DESCRIPTION OF SYMBOLS 10 Assembly battery 11 Battery laminated body 11a Cell 11b Laminated surface 11c Side surface 12 Heat radiation member 12a Heat radiation part 12b Bending part 13 Heat radiation sponge (heat radiation buffer material)

Claims (6)

A battery stack comprising a plurality of single cells arranged in a stack;
In at least two of the spaces outside the cell stack outside the cell between the cell stacks facing each other adjacent to the cell stack and at both ends of the cell stack in the stacking direction. Each having a heat dissipating part,
The assembled battery in which at least two heat dissipating parts adjacent in the stacking direction are configured by a single thin plate-like heat dissipating member connected via a bent part.   The assembled battery according to claim 1, wherein the heat dissipating part is disposed in all of the space.   The assembled battery according to claim 1 or 2, wherein the heat radiating member is configured by connecting all of the heat radiating portions by the bent portion.   The assembled battery according to any one of claims 1 to 3, wherein the bent portion includes a portion that is not in contact with the unit cell.   The assembled battery as described in any one of Claims 1 thru | or 4 provided with the thermal radiation buffer material which is arrange | positioned between the said laminated surface and the said thermal radiation part, and contacts both the said laminated surface and the said thermal radiation part.   The heat-dissipating buffer material is stretched so as to be in contact with the entire bent portion, and is bent and stretched along a side surface that is parallel to the side surface of the unit cell facing the bent portion. The assembled battery according to claim 5, which covers the entire side surfaces on both sides.

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