JP2012123983A - Secondary battery expansion restricting structure and secondary battery provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the battery container of a secondary battery from expanding outward due to internal gas pressure and also improve the heat radiation, insulation property and vibration resistance of a secondary battery by using a simple and easily manufacturable structure.SOLUTION: An expansion restricting structure A according to the present invention includes an expansion restricting member 28 which, surrounding the periphery of a battery container 2 accommodating electrode plates and electrolyte therein, restrains the battery container 2 from getting swollen and deformed outward by internal gas pressure. The expansion restricting member 28 is formed to be able to block the outwardly swelling deformation of side faces 2a-2d crossing faces at right angles, from which electrode terminals 7, 8 of the battery container 2 protrude. For example, an annular binding member 31 surrounding the side faces 2a-2d and a rod-like binding member 32 provided inside thereof are combined in a lattice shape, letting an outside surface of the battery container 2 exposed to the outside and also in contact with the outside surface to permit heat to transfer. Furthermore, the expansion restricting member 28 is provided with an insulating member 30 covering the periphery thereof. The insulating member 30 may be imparted a cushioning property.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery such as a lithium secondary battery, and more particularly to a structure for suppressing expansion of a secondary battery that suppresses expansion of a battery container during charge / discharge and improves heat dissipation. And a secondary battery including the same.

  In recent years, the trend of environmental conservation has been increasing worldwide, and hybrid vehicles and electric vehicles with a low degree of environmental pollution are becoming widespread in transportation. Such an electric vehicle is equipped with a large-capacity in-vehicle battery, and travels by driving an electric motor with electric power stored in the in-vehicle battery. As an in-vehicle battery, a lithium ion secondary battery is becoming widespread. Lithium-ion secondary batteries have higher energy density per unit weight than conventional lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, etc. Suitable as a battery.

  As a battery form of such a lithium ion secondary battery, roughly divided, a cylindrical one in which a spiral electrode body is enclosed in a bottomed cylindrical battery container and a plurality of rectangular and sheet-like electrodes are laminated. There is a laminated type (square type) in which a laminated electrode body is enclosed in a box-type battery container. The specific configuration of the laminated electrode body in the latter laminated type has a structure in which a required number of sheet-like positive and negative electrode plates are laminated via a sheet-like separator made of an insulator. And a nonaqueous electrolyte is enclosed with the inside of a battery container with this laminated electrode body, an electrochemical reaction is caused between a laminated electrode body and a nonaqueous electrolyte, and charging / discharging is performed.

  The non-aqueous electrolyte rises in temperature by repeated charge and discharge, and decomposes to generate gas. Therefore, in a laminated (rectangular) lithium ion secondary battery, the internal pressure of the battery container is increased by the gas pressure. The battery container tends to rise and swell outward. As a result, the binding force between the stacked electrode plates is reduced, the gas is caught between the electrode plates, lithium is not inserted / extracted at that portion, charging / discharging cannot be performed, and the battery capacity is reduced.

  In order to prevent this, as disclosed in Patent Document 1, the elasticity of rubber is used between the two outermost peripheral surfaces in the stacking direction of the stacked electrode body and the innermost surface of the battery container corresponding to the outermost peripheral surface. The electrode plates constituting the laminated electrode body are pressurized with each other, or as disclosed in Patent Document 2, on the widest surface among the six surfaces constituting the rectangular battery container. A concave groove is provided to increase the rigidity of this surface and to prevent the battery container from bulging outward due to the internal gas pressure, so that gas is not caught between the electrode plates.

JP 2009-004361 A JP 2010-080203 A

  However, in the configuration of Patent Document 1, since the pressurizing means is provided between the laminated electrode body and the battery container, the heat generated in the laminated electrode body is blocked by the pressurizing means and is not easily conducted to the battery container side. Therefore, the secondary battery is likely to overheat.

  On the other hand, in the configuration of Patent Document 2, since the battery container is reinforced by providing a concave groove in the battery container, it is difficult to manufacture the battery container, and a wasteful space is formed in the battery container. There is a problem that it cannot be applied to existing secondary batteries.

  The present invention has been made in order to solve the above-described problem, and has a simple and easy-to-manufacture structure to suppress the battery container of the secondary battery from expanding outward due to the pressure of the internal gas. Provided is a secondary battery expansion suppressing structure that can improve heat dissipation, insulation, and vibration isolation of the secondary battery, and can be applied to an existing secondary battery, and a secondary battery including the same. For the purpose.

In order to achieve the above object, the present invention provides the following means.
That is, the structure for suppressing expansion of a secondary battery according to the present invention includes an electrode plate and an electrolytic solution inside, and surrounds the periphery of the battery container from which the electrode terminal protrudes, and the battery container bulges outward. An expansion restraining member that suppresses the expansion, and the expansion restraining member includes an annular restraining member that surrounds a side surface orthogonal to a surface of the battery container from which the electrode terminal protrudes. According to this configuration, the expansion suppressing member can physically suppress the battery container of the secondary battery from expanding outward due to the pressure of the internal gas. In addition, the expansion suppressing member can be applied to an existing secondary battery.

  In the expansion suppression structure for a secondary battery according to the present invention, the expansion suppression member extends between the annular restraining member and the battery container in a direction perpendicular to the annular restraining member, It has at least 1 or more rod-shaped restraint member in the position which mutually opposes, It is characterized by the above-mentioned. According to this configuration, the expansion suppressing member can be made to have a robust structure, and the battery container can be more effectively prevented from expanding, and the heat dissipation of the secondary battery can be improved.

  In the secondary battery expansion suppressing structure according to the present invention, the rod-shaped restraining member is continuous with the heat conducting surface in thermal contact with the surface of the battery container, and the heat of the battery container is air. And a heat radiating surface for radiating heat. According to this configuration, since the heat of the secondary battery is transferred from the heat conducting surface to the rod-shaped restraining member, the heat is radiated from the heat radiating surface to the atmosphere. Can be further improved.

  The expansion suppression structure for a secondary battery according to the present invention further includes an insulating member that covers the periphery of the expansion suppressing member, and the insulating member has a plurality of openings on a surface that contacts the expansion suppressing member. It is characterized by that. According to this configuration, when a plurality of secondary batteries are assembled as an assembled battery, the insulation between the secondary batteries can be improved, and the opening is provided in the insulating member, so that the battery container and the expansion can be provided. Since the suppression member directly touches the outside air, the heat dissipation of the secondary battery can be further improved. Moreover, if the material which has cushioning properties is used for an insulating member, the impact and vibration which are added to a secondary battery can be buffered, and vibration proofing can be improved.

  And the secondary battery which concerns on this invention was equipped with the expansion suppression structure in each said aspect, It is characterized by the above-mentioned. According to this secondary battery, it is possible to suppress the battery container from bulging outward with a simple and easy-to-manufacture structure, and to improve heat dissipation, insulation, and vibration isolation.

  As described above, according to the secondary battery expansion suppressing structure according to the present invention, the battery container of the secondary battery is prevented from expanding outward due to the pressure of the internal gas by a simple and easy-to-manufacture structure. In addition, the heat dissipation, insulation, and vibration isolation of the secondary battery can be improved, and the expansion suppressing structure can be applied to the existing secondary battery.

  In addition, according to the secondary battery according to the present invention, the simple and easy-to-manufacture structure suppresses the battery container from bulging outward due to the pressure of the internal gas, and the heat dissipation and insulation of the secondary battery. Vibration isolation can be improved.

It is a fracture perspective view showing an example of an internal structure of a lithium ion secondary battery to which an expansion suppression structure according to an embodiment of the present invention can be applied. It is a front view of the expansion suppression member and insulating member which show 1st Embodiment of this invention. It is a side view of an expansion suppression member and an insulating member. It is a top view of an expansion suppression member and an insulating member. It is a top view which shows the state by which the secondary battery was inserted in the expansion suppression member and the insulation member. (A)-(f) is a cross-sectional view which shows the cross-sectional shape example of an expansion suppression member along the VI-VI line of FIG. It is a perspective view of the expansion suppression member and secondary battery which show the expansion suppression structure used as 2nd Embodiment of this invention. It is a top view which shows the example which curved the center part of the long side of the expansion suppression member in FIG. 7 inside. It is a cross-sectional view of an expansion suppression member, an interposed member, and a secondary battery showing an expansion suppression structure according to a third embodiment of the present invention.

  Hereinafter, an embodiment of the expansion suppressing structure according to the present invention will be described. Here, an expansion suppression structure for application to, for example, a lithium ion secondary battery will be described. However, the application of the present invention is not limited to a lithium ion secondary battery, and may be applied to other types of secondary batteries. it can.

First, prior to the description of the expansion suppressing structure according to the present invention, the overall configuration of the lithium ion secondary battery will be described.
As shown in FIG. 1, a lithium ion secondary battery 1 described here is, for example, a stacked type (square type) and includes a battery container 2 formed of an aluminum-based material. The battery container 2 is a box-shaped hollow container having a bottomed container body 3 that opens upward and a lid member 4 that closes the upper opening of the container body 3. The lid member 4 is liquid-tightly fixed to the container body 3 by a joining method such as welding. The battery case 2 includes a pair of opposed front plates 2a and 2b, a pair of opposed side plates 2c and 2d, a top plate 2e and a bottom plate 2f.

  A positive electrode terminal 7 and a negative electrode terminal 8 are attached to the lid member 4 (top plate 2e) via an insulator 6, and a safety valve 9 is provided therebetween. The safety valve 9 functions as a safety valve that opens to release the internal pressure when the internal pressure of the battery container 2 increases abnormally. A predetermined amount of non-aqueous electrolyte (not shown) containing lithium ions is stored inside the battery container 2.

  Inside the battery container 2, a plurality of electrode plates 11 and 12 formed in a rectangular sheet shape are alternately stacked, and the periphery of the electrode plate 12 is covered and accommodated by a separator 13. The electrode plates 11 and 12 are laminated in a direction parallel to the front plates 2a and 2b of the battery container 2, and the electrode plate 11 is on the positive electrode side and the electrode plate 12 is on the negative electrode side. The separator 13 is formed in a cylindrical shape (or bag shape) surrounding the electrode plate 12 with an insulating sheet or the like. Thus, the electrode plate 12 is surrounded by the separator 13, so that the positive electrode plate 11 and the negative electrode plate 12 are kept in an insulating state without contacting each other.

The electrode plates 11 and 12 were formed by applying lithium manganate (LiMn ₂ O ₄ ) or the like on the positive electrode side and carbon or graphite or the like on the negative electrode side to a sheet-like current collecting plate formed of aluminum or copper. Is. In addition, the separator 13 is, for example, a polypropylene resin plate formed with a ceramic layer. The ceramic layer is porous and allows the electrolytic components such as lithium ions of the nonaqueous electrolytic solution to pass therethrough.

  The electrode plates 11, 12 are rectangular electrode plate bodies 18, 19 and tongue-shaped electrode tabs 20, 21 provided so as to protrude upward from a portion near one end of the upper side of the electrode plate bodies 18, 19 ( Terminal connection portion). The electrode plate bodies 18 and 19 are portions that mainly contribute to the electric capacity of the lithium ion secondary battery 1 and are portions that are immersed in the nonaqueous electrolyte stored in the battery container 2. In addition, the electrode plate 11 which is a positive electrode plate is slightly smaller than the electrode plate 12 which is a negative electrode plate.

  The electrode plates 11 and 12 that are alternately stacked inside the battery container 2 are arranged so that the electrode tabs 20 and 21 are respectively distributed to one side and the other side in the electrode plate width direction. 20 and electrode tabs 21 are overlapped in the thickness direction. The plurality of electrode tabs 20 of the electrode plate 11 are bundled by a conductive lead plate 22 formed of a copper plate or the like and electrically connected to the positive electrode terminal 7. Similarly, the plurality of electrode tabs of the electrode plate 12 21 are bundled by the lead plate 23 and electrically connected to the negative electrode terminal 8.

  Then, an electrochemical reaction is performed between the positive and negative electrode plates 11 and 12 and the non-aqueous electrolyte stored in the battery container 2 to charge and discharge the lithium ion secondary battery 1. By repeating such charge and discharge, the temperature of the non-aqueous electrolyte rises and decomposes to generate gas. Therefore, in this rectangular lithium ion secondary battery 1, In particular, the widest front plates 2a and 2b tend to bulge outward. If it becomes like this, the restraint force between the electrode plates 11 and 12 laminated | stacked inside the battery container 2 will become small, gas will entangle between electrode plates 11 and 12, insertion of lithium in the site | part Desorption is not performed, charging and discharging cannot be performed, and battery capacity is reduced. Therefore, the expansion of the battery case 2 is suppressed by the expansion suppression structures A, B, and C described below.

[First Embodiment]
First, the expansion suppression structure A which is 1st Embodiment of this invention is demonstrated, referring FIGS. The expansion suppression structure A according to the first embodiment surrounds the periphery of the battery container 2 and covers the periphery of the expansion suppression member 28 having high rigidity that suppresses the battery container 2 from bulging outward and deforming ( (Enclosed) insulating member 30. 2, 3, and 4 are a front view, a side view, and a plan view, respectively, of the expansion suppressing member 28 and the insulating member 30. FIG. 5 is a plan view showing a state in which the lithium ion secondary battery 1 is inserted inside the expansion suppressing member 28 and the insulating member 30.

  The expansion suppressing member 28 has rigidity capable of preventing the center portion of the front plates 2a and 2b, which is at least the widest surface among the six surfaces of the battery case 2 formed in a square shape, from bulging outwardly and deforming. Configured. In the expansion suppressing member 28 in the present embodiment, not only the front plates 2a and 2b but also the side plates 2c and 2d are prevented from bulging outwardly.

  More specifically, the expansion restraining member 28 is formed in a bowl shape by assembling a plurality of annular restraining members 31 and rod-like restraining members 32 surrounding the outer periphery of the battery case 2, for example. The annular restraining member 31 is formed so as to surround the side surface of the battery case 2 orthogonal to the outer periphery of the top plate 2e from which the electrode terminals 7 and 8 protrude, that is, the front plates 2a and 2b and the side plates 2c and 2d. . Further, the rod-like restraining member 32 extends between the annular restraining member 31 and the battery container 2 in a direction orthogonal to the annular restraining member 31. The restraint member 31 and the restraint member 32 are fixed by, for example, welding. Since the expansion suppressing member 28 is formed in a lattice shape as described above, the outer surface of the battery container 2 is exposed to the outside in a portion where the expansion suppressing member 28 is not in contact with the outer surface of the battery container 2. It has become.

  For example, as shown in FIG. 6A, the restraining members 31 and 32 are formed of a steel wire having a round cross-sectional shape, and the restraining member 31 is bent and formed into a rectangular shape in plan view (see FIG. 4). As shown in FIG. 2, the restraining member 31 is arranged in, for example, 10 stages in the vertical direction, and, for example, 16 straight rod-like restraining members 32 are fixed so as to be in contact with the inner periphery thereof, whereby the expansion suppressing member 28 It is formed in a lattice shape (saddle shape). The upper and lower surfaces of the expansion suppressing member 28 are opened so as not to obstruct the flow of cooling air flowing in the vertical direction around the lithium ion secondary battery 1 by a cooling air blowing means (not shown). For example, a lattice-like restraining member similar to the outer peripheral portion may be provided on the bottom side.

  As shown in FIG. 5, the lithium ion secondary battery 1 is densely inserted into the inner peripheral portion of the expansion suppressing member 28 (the restricting member 31 and the restricting member 32). At this time, the restraining member 32 located on the innermost peripheral side of the expansion suppressing member 28 directly contacts the surface of the battery container 2. Thereby, the expansion suppressing member 28 is connected to the surface of the battery container 2 so as to be able to transfer heat. Here, when the restraining member 32 is in direct contact with the surface of the battery container 2, the heat of the battery container 2 is transmitted to the expansion suppressing member 28. For example, a silicon mat between the restraining member 32 and the battery container 2 is used. The expansion suppressing member 28 may be connected to the surface of the battery container 2 so as to be able to transfer heat by interposing a heat transfer material such as the above.

  On the other hand, the insulating member 30 surrounding the expansion suppressing member 28 is made of a material such as a highly insulating synthetic resin. The insulating member 30 may be formed of a material having cushioning properties such as urethane resin or rubber. The insulating member 30 is provided with a plurality of openings 35 on the front and side surfaces, from which the surfaces of the expansion restraining member 28 (restraining member 31 and restraining member 32) and the battery container 2 are exposed to the outside. .

  By the way, the cross-sectional shape of the restraining member 32 is not limited to the round cross section shown in FIG. 6A, but may be other shapes as shown in FIGS. 6B to 6E. For example, (b) is a square section, (c) is a trapezoid section, (d) is a channel section, and (e) is a square pipe section. When the cross-sectional shapes such as (b) to (e) are used, the restraining member 32 has a heat conduction surface 32a that is in contact with the surface of the battery container 2 so that heat can be transferred, and the heat conduction surface 32a. And a heat radiating surface 32b for radiating the heat of the air into the air. In the sectional shape of (d), the area of the heat radiation surface 32b is particularly large. As a modified example, as shown in (f), it is conceivable that at least a part of the restraining member 32 or the expansion suppressing member 28 is provided integrally with the battery container 2. In this case, there is no heat conducting surface 32a and only the heat radiating surface 32b is provided.

  According to the expansion suppression structure A configured as described above, the battery container 2 of the lithium ion secondary battery 1 is tightly surrounded by the rigid expansion suppression member 28, so that the battery of the lithium ion secondary battery 1 is used. The container 2 is physically restrained from expanding outward due to the pressure of the internal gas. For this reason, the restraint force between the electrode plates 11 and 12 stacked in the battery case 2 is reduced due to the swelling of the battery case 2, gas is caught between the electrode plates 11 and 12, and the battery capacity is reduced. You can eliminate concerns. Since the expansion suppressing member 28 is formed separately from the battery container 2, the expansion suppressing member 28 can be attached to the existing secondary battery so far to suppress the expansion of the battery container.

  The expansion suppressing member 28 may be any shape that can prevent the central portion of the front plates 2a and 2b, which is at least the widest surface, of the rectangular battery container 2 from bulging outward and deforming. The battery container 2 can be simply configured, and the expansion of the battery container 2 can be effectively suppressed without incurring great costs.

  The expansion restraining member 28 is formed in a lattice shape by combining a plurality of annular restraining members 31 surrounding the outer periphery of the battery case 2 and a rod-like restraining member 32, and these restraining members 31, 32 are formed on the battery case 2. In the portion not in contact with the outer surface, the outer surface of the battery case 2 is exposed to the outside, and a plurality of openings 35 are formed in the insulating member 30 that covers the outside of the expansion suppressing member 28 (restraining members 31 and 32). Since the surface of the expansion suppressing member 28 (restraining members 31 and 32) and the battery case 2 is exposed to the outside from here, the cooling air is brought into good contact therewith, and lithium having high heat generation The heat dissipation of the ion secondary battery 1 can be improved.

  A plurality of restraining members 31, 32 constituting the expansion suppressing member 28 are provided so as to surround the outer periphery of the battery container 2, and thus the expansion suppressing member 28 is formed in a lattice shape, so that the expansion suppressing member 28 is robust. The structure can effectively prevent the battery container 2 from expanding. If the battery container 2 does not swell, the internal pressure of the battery container 2 rises, but this causes the gasified non-aqueous electrolyte to be liquefied again, so that the function of the lithium ion secondary battery 1 is maintained in a healthy state. Can do.

  Moreover, in this expansion suppression structure A, the restraining members 31 and 32 constituting the expansion suppression member 28 are in contact with the surface of the battery container 2 so that heat can be transferred, so that the expansion suppression member 28 itself functions as a radiator. The heat of the lithium ion secondary battery 1 is dissipated into the atmosphere. For this reason, the heat dissipation of the lithium ion secondary battery 1, ie, the cooling property, can be improved.

  When the cross-sectional shape of the restraining member 32 is formed as shown in FIGS. 6B to 6E and the like, as described above, the restraining member 32 is thermally conductive to be in thermal contact with the surface of the battery container 2. A surface 32a and a heat radiating surface 32b for radiating the heat of the battery case 2 into the air are formed continuously with the heat conducting surface 32a, and the restraining member 32 is in contact with the battery case 2 on the surface. The heat of the secondary battery 1 is efficiently transferred from the heat conducting surface 32a to the restraining member 32 and radiated from the heat radiating surface 32b to the atmosphere. Here, the heat dissipation efficiency can be increased by increasing the area of the heat radiating surface 32b to be larger than the area of the heat conducting surface 32a. In particular, if the area of the heat radiation surface 32b is doubled as shown in FIG. Alternatively, if the restraining member 32 is formed in a pipe shape as shown in FIG. 6E and the cooling air passes through the inside, the cooling efficiency can be further improved.

  Further, since the periphery of the expansion suppressing member 28 is covered (enclosed) by the insulating member 30, when a plurality of lithium ion secondary batteries 1 are assembled as an assembled battery, the insulation between the batteries is improved. Can be improved. Moreover, if the insulating member 30 is formed of a material having cushioning properties such as urethane resin or rubber, the shock and vibration applied to the lithium ion secondary battery 1 can be buffered by the insulating member 30 and the vibration-proofing property can be improved. . Since the opening 35 is provided in the insulating member 30, the cooling performance of the lithium ion secondary battery 1 is not hindered.

[Second Embodiment]
Next, an expansion suppression structure B that is a second embodiment of the present invention will be described with reference to FIGS. In this expansion suppression structure B, an expansion suppression member 38 formed in a rectangular and annular band shape with a thick metal plate or the like is wrapped around the battery container 2 of the lithium ion secondary battery 1. The configuration of the lithium ion secondary battery 1 is the same as that of the first embodiment. The width of the expansion suppressing member 38 is set to about a fraction of the height dimension H of the battery container 2. As a result, a portion of the battery container 2 where the expansion suppression member 38 is not mounted is exposed to the outside, and the cooling performance of the lithium ion secondary battery 1 is not hindered.

  The expansion suppressing member 38 has a rigidity capable of preventing the center portion of the front plates 2a and 2b, which is at least the widest of the six surfaces of the battery case 2 formed in a square shape, from bulging outwardly. However, not only the front plates 2a and 2b but also the side plates 2c and 2d can be prevented from bulging and deforming. That is, the side surface orthogonal to the outer periphery of the top plate 2e from which the electrode terminals 7 and 8 protrude, that is, the front plates 2a and 2b, is provided by the expansion suppressing member 38 having rigidity higher than that of the battery case 2 itself. The side plates 2c and 2d are preferably configured so as to be closely surrounded. The expansion suppressing member 38 can prevent the central portions of the front plates 2a and 2b (side plates 2c and 2d) of the battery container 2 from expanding outward due to the internal gas pressure.

  More preferably, as shown in FIG. 8, the center of the long side 38a of the expansion suppressing member 38 may be curved inward in plan view. Thereby, since the center part of front board 2a, 2b of battery container 2 is pressed by moderate pressure by long side 38a, it can suppress more effectively that the center part of front board 2a, 2b swells outside. . Moreover, even if the expansion suppressing member 38 is not particularly fixed to the battery container 2, the expansion suppressing member 38 can be positioned at a height near the center of the battery container 2 in the height direction by the holding force of the long side 38 a. It can be easily attached and detached. The short side 38b may be curved inward along with the long side 38a.

  According to the expansion suppression structure B configured as described above, the expansion suppression member 38 can be made very simple and inexpensive, and cost increase and weight increase due to the provision of the expansion suppression member 38 can be minimized. it can.

[Third Embodiment]
Next, an expansion suppression structure C according to a third embodiment of the present invention will be described with reference to FIG. Here, similarly to the expansion suppression member 38 shown in FIG. 7, the expansion suppression member 41 formed in a rectangular and annular band shape with a thick metal plate or the like is provided around the battery container 2 of the lithium ion secondary battery 1. It is wrapped in. The expansion suppressing member 41 has a short side 41b in contact with the side plates 2c and 2d of the battery case 2, but the long side 41a is not in contact with the front plates 2a and 2b of the battery case 2, and the long side 41a An elastic member 43 made of rubber or the like is interposed between the front plates 2a and 2b.

  According to the expansion suppression structure C configured in this way, the front plates 2a and 2b of the battery case 2 are pressed with an appropriate pressure by the elastic force of the elastic member 43, so that the central portions of the front plates 2a and 2b are outward. Swelling can be suppressed. In addition, if the internal pressure of the battery container 2 rises and the front plates 2a and 2b try to expand outward, the elastic valve 43 is allowed to expand to some extent by the elasticity of the elastic member 43, so that the safety valve 9 (see FIG. 7) is provided. The time until the valve is opened can be delayed.

  In addition, as a material of the elastic member 43, a material having a thermal expansion property may be selected. In this way, as the temperature of the lithium ion secondary battery 1 rises, the elastic member 43 undergoes thermal expansion and the thickness thereof increases, so that the force for pressing the front plates 2a and 2b of the battery container 2 increases, and the front plate Swelling of 2a and 2b can be more effectively suppressed.

The technical scope of the present invention is not limited to the configurations of the first to third embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first embodiment, the expansion suppressing member 28 formed of a metal bar and the insulating member 30 formed of an insulating material such as a synthetic resin are separately configured and combined. For example, the periphery of the expansion suppressing member 28 may be integrally formed by casting with an insulating member 30. Alternatively, the expansion suppressing member 28 may be formed of an insulating material and the insulating member 30 may be omitted.

Further, the expansion suppressing member 28 does not necessarily have to have a configuration in which wires are combined. For example, the expansion suppressing member 28 may be configured by a slightly thick flat plate and may have a configuration in which a ventilation hole is provided. Furthermore, when combining wire, it is not always necessary to arrange them in the vertical and horizontal directions, and for example, they may be in the oblique direction. In short, any shape may be used as long as the battery container 2 can be prevented from expanding outward.
Further, in each embodiment, when a plurality of lithium ion secondary batteries are accommodated in a battery holder and used as an assembled battery, the battery holder itself may be configured as an expansion suppressing member.

1 Lithium ion secondary battery (secondary battery)
2 Battery container 2a, 2b Front plate (side surface orthogonal to outer periphery of surface from which electrode terminal protrudes)
2c, 2d side plate (side surface orthogonal to the outer periphery of the surface from which the electrode terminal protrudes)
2e Top plate (surface from which the electrode terminal of the battery container protrudes)
2f Bottom plate 7, 8 Electrode terminal 11, 12 Electrode plate 13 Separator 28, 38, 41 Expansion restraining member 30 Insulating member 31 Annular restraining member 32 Rod-like restraining member 32a Heat conducting surface 32b Heat radiation surface 35 Openings A, B, C Expansion Suppression structure

Claims (5)

An electrode plate and an electrolytic solution are housed inside, and around the battery container from which the electrode terminal protrudes to the outside, including an expansion suppressing member that suppresses the battery container from expanding and deforming outwardly,
The expansion suppressing structure of a secondary battery, wherein the expansion suppressing member includes an annular restraining member surrounding a side surface orthogonal to a surface of the battery container from which the electrode terminal protrudes.   The expansion restraining member extends between the annular restraining member and the battery container in a direction orthogonal to the annular restraining member, and has at least one rod-like restraining member at a position facing the side surface. The structure for suppressing expansion of a secondary battery according to claim 1, comprising:   The rod-shaped restraining member has a heat conducting surface that is in thermal contact with the surface of the battery container, and a heat radiating surface that is continuous with the heat conducting surface and dissipates heat from the battery container into the air. The expansion suppression structure for a secondary battery according to claim 2.   The insulating member which covers the circumference | surroundings of the said expansion | swelling suppression member is further included, and the said insulating member has a some opening part on the surface which the said expansion | swelling suppression member contacts, The Claim 1 characterized by the above-mentioned. Secondary battery expansion suppression structure.   A secondary battery comprising the expansion suppressing structure according to claim 1.

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