JP2015022915A - Secondary battery pack and mobile body including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery pack capable of reducing a load applied on an outer case by absorbing the swell and deformation of a single cell housed in the outer case, thereby capable of preventing the outer case from being deformed and damaged.SOLUTION: A secondary battery pack 100 includes: an outer case 101; a plurality of single cells B housed in a line at the inside of the outer case 101; and a spacer 161 inserted into at least one of between single cells B adjacent each other and between a single cell B disposed at an end part of the single cells B in an arrangement direction and side plates 105b, 105c of the outer case 101, the side plates being adjacent to the single cell B, and forming a space S for absorbing the swell and deformation of a side surface of the single cell B therebetween.

Description

  The present invention relates to a secondary battery pack including a plurality of single cells in an outer case, and a moving body including the same.

  A relatively large-capacity secondary battery pack for supplying electric power to the motor is mounted on a vehicle such as an electric vehicle that runs using the motor as a drive source. This secondary battery pack is configured by accommodating a plurality of single cells of a secondary battery in an outer case (see, for example, Patent Document 1). A single cell of a secondary battery is composed of a positive electrode, a negative electrode, and an electrolytic solution (electrolyte) that are power generation elements accommodated in a battery container. Moreover, the side plate of a single-cell battery container may swell due to an increase in internal pressure. Then, the proposal about the container shape which suppresses such a bulging deformation is made | formed (for example, refer patent document 2).

JP 2009-205986 A Utility Model Registration No. 3001823

In the outer case of the secondary battery pack, the side plates of a plurality of single cells bulge, and if this accumulates, a large force is also applied to the side plate of the outer case, and the outer case may be deformed or damaged. is there.
The technique described in Patent Document 2 is intended to increase the strength and suppress deformation by forming a recess in the side plate of the battery container. However, by suppressing the bulging deformation of the side plate, There may be a load. In addition, since the bulging deformation of the side plate cannot be completely eliminated, when the number of the accommodated single cells is large, a load is applied to the outer case due to the accumulation of the bulging deformation.
In view of the above circumstances, the present invention can reduce the load applied to the exterior case by absorbing the bulging deformation of the single cell accommodated in the exterior case, and prevent deformation and damage of the exterior case. An object of the present invention is to provide a rechargeable battery pack that can be manufactured and a mobile body including the same.

The secondary battery pack of the present invention is
An exterior case,
A plurality of single cells housed side by side in the exterior case;
Inserted between at least one of the unit cells adjacent to each other and between the unit cell disposed at the end of the unit cell in the arrangement direction and the side plate of the exterior case adjacent to the unit cell, A spacer that forms a gap for absorbing the bulging deformation of the side surface of the single cell;
It has.

  The moving body of the present invention is mounted with the above secondary battery pack as a power source.

  ADVANTAGE OF THE INVENTION According to this invention, the burden concerning an exterior case can be reduced by absorbing the bulging deformation | transformation of the single cell accommodated in the exterior case, and the deformation | transformation and damage of an exterior case can be prevented.

1 is a schematic diagram showing in principle the basic structure of a power generation element in a molten salt battery. It is a perspective view which shows simply the lamination structure of a molten salt battery main body (main-body part as a battery). It is a cross-sectional view about the structure similar to FIG. It is a perspective view which shows the outline of the external appearance of the molten salt battery (single cell) of the state accommodated in the battery container. 1 is a longitudinal sectional view along one direction showing a secondary battery pack according to a first embodiment of the present invention. It is a longitudinal cross-sectional view along the other direction of the secondary battery pack. It is a disassembled perspective view of the secondary battery pack. It is a schematic perspective view which decomposes | disassembles and shows a part of the secondary battery pack. It is a longitudinal cross-sectional view which expands and shows a part of FIG. It is a longitudinal cross-sectional view which shows the secondary battery pack which concerns on the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows a part of FIG. It is the schematic which shows the electric vehicle carrying a secondary battery pack.

[Summary of Embodiment of the Present Invention]
First, the gist of the embodiment of the present invention will be listed and described. In addition, each embodiment described below can also combine the part arbitrarily.
(1) The secondary battery pack of the present invention is
An exterior case,
A plurality of single cells housed side by side in the exterior case;
Inserted between at least one of the unit cells adjacent to each other and between the unit cell disposed at the end of the unit cell in the arrangement direction and the side plate of the exterior case adjacent to the unit cell, And a spacer for forming a gap for absorbing the bulging deformation of the side surface of the single cell.

  According to this configuration, the bulging deformation generated on the side surface of the single cell is absorbed by the gap formed between the adjacent single cells or between the single cell and the side plate of the exterior case. Therefore, it is possible to prevent the outer case from being deformed or damaged due to the plurality of single cells bulging and deforming.

(2) The said spacer may form the said clearance gap in the position corresponding to at least a center part among the side surfaces of the said single cell.
With such a configuration, the bulging deformation at the central portion of the side surface of the single cell where the bulging deformation is greatest can be suitably absorbed.

(3) The side plate located at the end portion in the arrangement direction of the exterior case is detachably attached to another adjacent side plate, and is attached so that the pressing force in the arrangement direction applied to the single cells and the spacers can be adjusted. It is preferable.
According to this, the single cell and the spacer in the outer case can be pressed by the side plate located at the end portion in the arrangement direction of the outer case, and these can be stored without rattling.

(4) It is preferable that the said spacer is cyclically | annularly formed along the outer peripheral part of the side surface of the said single cell.
According to this configuration, the unit cell and the spacer can be brought into direct contact with each other in the widest possible range at portions other than the central portion of the side surface of the unit cell. Can be suitably suppressed. The “annular shape” is not limited to a completely continuous form (closed form) in the circumferential direction, and may be a form (open form) divided in a part of the circumferential direction.

(5) The spacer of the above (4) may be formed with an opening that communicates the inner peripheral side and the outer peripheral side of the spacer.
(6) Moreover, an electrical component may be arrange | positioned in the said clearance gap, and the wiring of the said electrical component may be pulled out to the outer peripheral side of the said spacer through the said opening.
According to this configuration, an electrical component such as a temperature sensor can be arranged using the gap, and the wiring can be drawn out of the spacer through the opening.

(7) It is preferable that the said spacer has a corner | angular part in the inner peripheral side edge, and this corner | angular part is formed in R shape.
With such a configuration, it is possible to prevent stress concentration at the corners at the inner peripheral edge of the spacer, and to prevent damage starting from the corners.

(8) It is preferable that the said clearance gap formed between the mutually adjacent single cells has the width | variety more than the sum of the largest bulging dimension of the side surface of both single cells.
Even if both the single cells are bulged and deformed to the maximum by such a configuration, the deformation can be reliably absorbed.

(9) In the secondary battery pack according to (8), the gap formed between the unit cells at the end in the arrangement direction and the side plate of the exterior case has a maximum bulging dimension on the side surface of the unit cell. The width is preferably smaller than the gap formed between the single cells adjacent to each other.
According to this configuration, the gap formed between the unit cells at the end in the arrangement direction and the side plate of the exterior case can reliably absorb the bulging deformation of the unit cells, and the gap Can be made as small as possible to reduce the dimensions of the outer case in the arrangement direction.

(10) The secondary battery pack may further include a heater that contacts and heats the single cell.
In the case of a secondary battery pack that heats a single cell with a heater in this way, since the bulging deformation of the single cell may become larger, between the adjacent single cells, as in the embodiment of the present invention, It is more preferable to insert a spacer for forming a gap between the single cells at the end in the arrangement direction and the side plate of the outer case.

(11) The exterior case has a lid that can be opened and closed, and the lid projects to the inside of the exterior case and presses the outer surface of the unit cell to hold the unit cell in the lid. It is preferable that a fixture for fixing to the outer case is provided.
With such a configuration, the single cell can be fixed by the fixture so that the single cell does not float in the outer case due to vibration applied to the secondary battery pack. Conventionally, there has been a case where a bolt is inserted into and fixed to the outer case and the single cell together (for example, see Patent Document 1). In this case, a space for forming a bolt insertion hole is provided in the outer case. The case and the single cell must be secured, and there is a possibility that the single cell and the outer case, and thus the secondary battery pack, will be enlarged. Moreover, since it is necessary to process the single cell itself for fixing to an exterior case, the structure of a single cell may be specialized and versatility may fall. According to the embodiment of the present invention, such inconvenience can be solved.

(12) A mobile body according to an embodiment of the present invention is mounted with the secondary battery pack according to any one of (1) to (11) as a power source.
According to this configuration, it is possible to prevent the outer case mounted on the moving body from being deformed or damaged due to the bulging deformation of each single cell.
Moreover, when the fixing tool is provided in the cover body of the exterior case, it is possible to suppress the single cell from moving in the exterior case due to vibration accompanying the movement of the moving body.

[Details of the embodiment of the present invention]
Next, the molten salt battery used for the secondary battery pack according to the embodiment of the present invention will be described.
[Basic structure of molten salt battery]
FIG. 1 is a schematic diagram showing in principle the basic structure of a power generation element in a molten salt battery. In the figure, the power generation element includes a positive electrode 1, a negative electrode 2, and a separator 3 interposed therebetween. The positive electrode 1 is composed of a positive electrode current collector 1a and a positive electrode material 1b. The negative electrode 2 includes a negative electrode current collector 2a and a negative electrode material 2b.

The material of the positive electrode current collector 1a is, for example, an aluminum nonwoven fabric (wire diameter: 100 μm, porosity: 80%). The positive electrode material 1b is a mixture of, for example, NaCrO ₂ as a positive electrode active material, acetylene black, PVDF (polyvinylidene fluoride), and N-methyl-2-pyrrolidone at a mass ratio of 85: 10: 5: 100. It is a thing. And what was kneaded in this way is filled in the positive electrode collector 1a of an aluminum nonwoven fabric, and after drying, it presses at 100 Mpa, and it forms so that the thickness of the positive electrode 1 may be set to about 1 mm.
On the other hand, in the negative electrode 2, an Sn—Na alloy containing, for example, tin as a negative electrode active material is formed on the aluminum negative electrode current collector 2a by plating.

  The separator 3 interposed between the positive electrode 1 and the negative electrode 2 is obtained by impregnating a glass non-woven fabric (thickness 200 μm) or a polyolefin sheet (thickness 50 μm) with a molten salt as an electrolyte. This molten salt is, for example, a mixture of 56 mol% NaFSA (sodium bisfluorosulfonylamide) and 44 mol% KFSA (potassium bisfluorosulfonylamide), and has a melting point of 57 ° C. At a temperature equal to or higher than the melting point, the molten salt melts and becomes an electrolytic solution in which high-concentration ions are dissolved, and touches the positive electrode 1 and the negative electrode 2. Moreover, this molten salt is nonflammable. The operating temperature range of this molten salt battery is 57 ° C to 190 ° C.

In addition, although the material, component, and numerical value of each part mentioned above are suitable examples, it is not limited to these.
For example, in addition to the above, a mixture of NaFSA and LiFSA, KFSA, RbFSA or CsFSA is also suitable as the molten salt. In addition, other salts composed of organic cations and the like may be mixed. Generally, the molten salt includes (a) a mixture containing NaFSA, (b) a mixture containing NaTFSA (sodium bistrifluoromethylsulfonylamide), ( c) Mixtures containing NaFTA (sodium fluorosulfonyl-trifluoromethylsulfonylamide) are suitable. It is also possible to mix two or more of (a) to (c). In these cases, since the molten salt of each mixture has a relatively low melting point, a state in which high-concentration ions are dissolved with a small amount of heating can be realized, and the molten salt battery can be operated.

[Specific structure of molten salt battery]
Next, a more specific configuration of the power generation element of the molten salt battery will be described. FIG. 2 is a perspective view schematically showing a laminated structure of a molten salt battery main body (main body portion as a battery) 10, and FIG. 3 is a cross-sectional view of the same structure.
2 and 3, a plurality (six are shown) of rectangular flat plate-like negative electrodes 2 and a plurality (five are shown) of rectangles accommodated in a bag-like separator 3 respectively. The flat positive electrodes 1 are opposed to each other and are stacked in the vertical direction in FIG. 3, that is, in the stacking direction, to form a stacked structure.

  The separator 3 is interposed between the positive electrode 1 and the negative electrode 2 adjacent to each other. In other words, the positive electrode 1 and the negative electrode 2 are alternately stacked via the separator 3. For example, 20 positive electrodes 1 and 21 negative electrodes 2 and 20 separators 3 as “bags”, but 40 intervening between positive electrodes 1 and 2 are actually stacked. is there. The separator 3 is not limited to a bag shape, and may be 40 separated.

  In FIG. 3, the separator 3 and the negative electrode 2 are drawn so as to be separated from each other, but they are in close contact with each other when the molten salt battery is completed. Naturally, the positive electrode 1 is also in close contact with the separator 3. In addition, the vertical and horizontal dimensions of the positive electrode 1 are smaller than the vertical and horizontal dimensions of the negative electrode 2 in order to prevent the generation of dendrites, and the outer edge of the positive electrode 1 passes through the separator 3. Thus, it faces the peripheral edge of the negative electrode 2.

[Practical single cell]
The molten salt battery main body 10 configured as described above is a “single cell” (single cell) forming a physical individual as a molten salt battery, for example, by being accommodated in a rectangular parallelepiped battery container made of an aluminum alloy. / Unit cell).
FIG. 4 is a perspective view showing an outline of the appearance of the molten salt battery main body in the state accommodated in the battery container 11, that is, the single cell B of the molten salt battery. 2 and 3, the terminals 1t and 2t are drawn out from the battery case 11 while maintaining insulation from the battery case 11 from the positive electrode 1 and the negative electrode 2, respectively. The inner surface of the battery container 11 is insulated, and the battery container 11 is electrically insulated from the molten salt battery body 10 inside. In FIG. 4, the long side direction of the upper surface of the single cell B is indicated by X, the short side direction is indicated by Y, and the vertical direction is indicated by Z. The terminals 1t and 2t are provided on the upper surface of the single cell B and closer to the end in the X direction.

[First Embodiment of Secondary Battery Pack]
FIG. 5 is a longitudinal sectional view along one direction (Y direction) showing the secondary battery pack 100 according to the first embodiment of the present invention, and FIG. FIG. 7 is an exploded perspective view of the secondary battery pack. 5 to 7, the directions of XYZ correspond to those in FIG. 4. In FIG. 7, the lid 106 of the outer case 101 is omitted.
The secondary battery pack 100 includes an outer case 101, an assembled battery 103, and a heater 104. The exterior case 101 includes a case main body 105 and a lid body 106, and is formed in a hexahedral box shape.

  The lid 106 is constituted by an upper plate of the exterior case 101. The case main body 105 includes a bottom plate 105a of the outer case 101 and four side plates 105b to 105e. Therefore, the case main body 105 has an opening 105 f at its upper end, and the opening 105 f is closed by the lid 106. The lid body 106 is detachably attached (can be opened and closed) to the case body 105 by a fixing screw (not shown) or the like. A plurality of fixtures 110 for fixing the single cell B are provided on the lower surface of the lid body 106. The outer case 101 preferably has rigidity (hardness) and heat conductivity capable of maintaining the entire shape, and is formed of a metal material such as iron or aluminum alloy, for example.

The assembled battery 103 is configured by arranging a plurality of (eight in the example shown in FIG. 5) unit cells B in the Y direction, and is disposed in the outer case 101. Spacers 161 are inserted between the single cells B and between the single cells B and the outer case 101. The number of single cells B can be appropriately changed according to the required voltage or current.
The heater 104 is, for example, a sheet heater (for example, about 3 mm thick) in which a heating wire is embedded using silicon rubber as a base material. The heater 104 is in contact with the outer case 101 and heats it. The heater 104 of the present embodiment is provided so as to be in contact with the bottom surface of the outer case 101 and both end surfaces in the X direction. However, the arrangement of the heater 104 is not particularly limited. For example, the heater 104 may be provided so as to be in contact with both end surfaces of the outer case 101 in the Y direction, and each single cell is provided inside the outer case 101. A heater 104 may be provided in contact with the outer surface of B. The heater 104 of this embodiment heats the single cell B to a temperature of 60 ° C. to 100 ° C., for example.

[Configuration of Spacer 161]
Spacers 161 are inserted between the single cells B adjacent to each other in the Y direction and between the single cells B arranged at both ends in the Y direction and the side plates 105b and 105c of the outer case 101, respectively. The spacer 161 is provided to form a gap S between the single cells B or between the single cells B and the side plates 105b and 105c.
The spacer 161 is made of a metal material such as an aluminum alloy or a hard synthetic resin material. In addition, the spacer 161 is formed on the outer peripheral portion of the side surfaces of the single cells B that are adjacent to each other and the side surfaces of the single cells B that are opposed to the side plates 105b and 105c of the exterior case 101 (hereinafter also referred to simply as “opposing side surfaces”). It is formed in a substantially ring shape (annular) or frame shape along. Therefore, a gap S is formed corresponding to the central portion on the opposite side surface of the single cell B.

  In the secondary battery pack 100, the pressure inside the single cell B may increase during charging or the like, and the side surface of the single cell B may bulge and deform. In addition, when the secondary battery pack 100 is heated by the heater 104 as in the present embodiment, the bulging deformation may become larger. In this regard, in the secondary battery pack 100 of the present embodiment, the gap S is formed in the center portion on the opposite side surface of the single cell B. Therefore, as shown by a two-dot chain line in FIG. 9, this deformation can be absorbed by the gap S even when the side surface of the single cell B bulges and deforms during charging or the like. Therefore, it is possible to prevent the outer case 101 from being deformed or damaged by applying a force in the Y direction to the outer case 101 due to the bulging deformation of each single cell B. Further, since the spacer 161 is provided along the outer peripheral portion on the opposing side surface of the single cell B, the gap S can be formed corresponding to the center portion of the opposing side surface that bulges most, and the bulging deformation is eliminated by the gap. S can be reliably absorbed by S.

  Further, as shown in FIG. 9, the width a of the gap Sa formed between the opposing side surfaces of the unit cells B adjacent to each other is assumed to be the maximum expected when the opposing side surfaces of both unit cells B bulge and deform. The dimension is set to be larger than the sum of the bulging dimensions. Further, the width b of the gap Sb formed between the single cell B and the side plates 105b and 105c of the outer case 101 is an estimated maximum bulging dimension when the opposing side surface of the single cell B is bulged and deformed. Is set to a larger dimension. Therefore, even if the opposing side surfaces of the single cells B bulge and deform, the adjacent single cells B and the single cells B and the side plates 105b and 105c of the outer case 101 do not contact each other. Further, due to the difference in the thickness of the spacer 161, the width b of the gap Sb is formed smaller than the width a of the gap Sa, and is about ½ of the width a. By comprising in this way, the increase in the dimension of the Y direction of the exterior case 101 accompanying provision of the clearance gap S can be suppressed.

As shown in FIG. 6, the corner 161b of the inner peripheral edge of the spacer 161 is formed in an R shape. Therefore, stress concentration at the corner portion 161b is prevented, and damage to the spacer 161 starting from the corner portion 161b can be prevented.
In addition, a notch (opening) 161 a that connects the inner peripheral side and the outer peripheral side of the spacer 161 is formed in the upper portion of the spacer 161. In addition, electrical components such as a temperature sensor 163 are attached to the opposing side surface of the single cell B inside the spacer 161. The wiring of the electrical component is drawn upward through the notch 161a. Therefore, the gap S formed between the adjacent single cells B or between the single cells B and the side plates 105b and 105c of the exterior case 101 can be used as a space for arranging electrical components such as a temperature sensor. By forming the notch 161 a in the spacer 161, the wiring of the electrical component can be drawn out to the outside of the spacer 161.

  As shown in FIG. 8, the side plate 105 c disposed at one end portion in the Y direction of the case main body 105 in the outer case 101 is configured to be detachable by fixing screws 162 with respect to other side plates 105 d and 105 e orthogonal to each other. Yes. Specifically, the side plate 105c is formed with an insertion hole 105c1 through which the fixing screw 162 is inserted, and the other side plates 105d and 105e are formed with female screw holes 105d1 and 105e1 into which the fixing screw 162 is screwed. Then, the side plate 105c is attached to the other side plates 105d and 105e by screwing the fixing screw 162 inserted through the insertion hole 105c1 into the female screw holes 105d1 and 105e1. Then, by adjusting the fastening torque (screwing amount) of the fixing screw 162, the pressing force in the Y direction applied to the single cell B and the spacer 161 can be adjusted, and the single cell B in the outer case 101 can be adjusted. Shaking in the Y direction can be suitably prevented.

  In the present embodiment, the spacer 161 may not be continuous over substantially the entire outer peripheral portion of the opposing side surface of the single cell B, and is separated into an upper portion, a lower portion, and both side portions of the outer peripheral portion. It may be provided. Moreover, the spacer 161 may be provided only in a part of the upper part, lower part, and both side parts of the outer peripheral part on the opposite side surface of the single cell B.

[Configuration of Fixing Device 110]
The lid 106 of the outer case 101 is provided with a plurality of fixtures 110 for fixing the single cell B to the outer case 101. The fixture 110 protrudes downward from the lower surface of the lid 106 above each unit cell B, and a lower end surface thereof is pressed against the upper surface of the unit cell B.
More specifically, the fixture 110 is formed in a columnar shape, a prism shape, a cylindrical shape, a rectangular tube shape, a block shape or the like that is long in the vertical direction. The vertical height of the fixture 110 (the amount of protrusion from the lid 106) is larger than the height of the terminals 1t and 2t of the single cell B (see FIG. 6). The fixture 110 is in contact with a position on the upper surface of the single cell B away from the electrode terminals 1t and 2t, for example, the center in the X direction. Moreover, although components such as an electric wiring and a pressure relief valve (not shown) are arranged in the vicinity of the terminals 1t and 2t, the fixture 110 is arranged at a position avoiding these electric wiring and components.

The fixture 110 is pressed between the lid 106 and the single cell B by being pressed against the upper surface of the single cell B. Therefore, each single cell B is sandwiched between the lid body 106 (fixing tool 110) of the outer case 101 and the bottom plate 105a, and the movement in the vertical direction is restricted.
Therefore, for example, when the secondary battery pack 100 is mounted on a vehicle, the vertical movement of the single cell B is suppressed by the fixture 110 even if vibration is transmitted to the secondary battery pack 100 as the vehicle travels. Therefore, it is possible to prevent the single cell B from floating upward in the outer case 101 and scratching the single cell B or applying a force to the electrical wiring. The assembled battery 103 in the outer case 101 is supported by the side plates 105b and 105c of the case main body 105 via the spacer 161 at both end surfaces in the Y direction, so that the movement in the Y direction with respect to the outer case 101 is also limited. Since both end faces in the X direction are supported by the side plates 105d and 105e of the case main body 105, movement in the X direction with respect to the outer case 101 is also restricted. Accordingly, the single cell B hardly shakes in the XY direction.

  Further, conventionally, the exterior case 101 and the single cell B may be fastened together by bolts (see, for example, Patent Document 1), and in this case, a space for forming a bolt insertion hole is provided in the exterior case 101 or In this embodiment, since such a space is not necessary, it is possible to prevent the single cell B and the outer case 101 from being enlarged and the secondary battery pack 100 from being enlarged. it can. Further, by providing the fixture 110 on the lid 106 of the outer case 101, the unit cell B itself does not need to be processed to be fixed to the outer case 101, so the structure of the single cell B becomes special. The versatility of the single cell B can be improved.

Further, since the fixture 110 protrudes from the inner surface of the lid 106 with a dimension larger than the protruding amount of the terminals 1t and 2t provided on the upper surface of the single cell B, the single cell provided with the terminals 1t and 2t is provided. Even the outer surface of B can be suitably pressed down.
The fixture 110 is made of a material having a rigidity that can limit the vertical movement of the single cell B. For example, the fixture 110 can be formed of a metal material or a hard synthetic resin material. The fixture 110 can be formed of the same material as the lid 106, for example, an aluminum alloy.

  It is preferable to employ a configuration that prevents relative sliding between the lower end portion of the fixture 110 and the upper surface of the single cell B. For example, it is possible to employ a configuration in which an adsorption member such as a suction cup is provided at the lower end of the fixture 110 and the adsorption member is adsorbed on the upper surface of the single cell B. Further, it is possible to employ a configuration in which a member having a large friction coefficient such as rubber or a member having adhesiveness is provided at the lower end portion of the fixture 110 and these members are brought into contact with the upper surface of the single cell B. However, it is preferable to employ a member with little vertical deformation so that any member does not hinder the restriction of the vertical movement of the single cell B.

Since the reaction force when the fixing tool 110 presses down the single cell B is applied to the lid body 106, it is desirable that the lid body 106 has a rigidity that does not cause distortion due to the reaction force. For example, the lid body 106 can be increased in rigidity by being formed thicker than the bottom plate 105a and the side plates 105b to 105e constituting the case main body 105.
In addition, the fixing tool 110 in this embodiment can also be abbreviate | omitted.

[Second Embodiment of Secondary Battery Pack]
FIG. 10 is a longitudinal sectional view of a secondary battery pack 100 according to the second embodiment of the present invention, and FIG. 11 is an enlarged longitudinal sectional view showing a part of FIG.
In the present embodiment, the fixtures 150A and 150B provided on the lid body 106 of the outer case 101 not only press the upper surface of the single cell B, but are arranged between the adjacent single cells B and at both ends in the Y direction. It also has a function as a spacer that forms a gap S between the formed single cell B and the side plates 105b and 105c of the outer case 101. Specifically, as shown in FIG. 11, the fixture 150A other than the fixtures 150B at both ends in the Y direction in FIG. 10 is provided with a holding portion 150a that holds the upper surface of the single cell B at one end in the Y direction. The other end in the Y direction is provided with an insertion portion 150b that protrudes below the pressing portion 150a and is inserted between the two single cells B. In addition, the fixture 150B at both ends in the Y direction in FIG. 10 is provided with a pressing portion 150a for pressing the upper surface of the single cell B at one end portion in the Y direction, and below the pressing portion 150a at the other end portion in the Y direction. The insertion portion 150b1 is provided so as to protrude between the side plates 105b and 105c of the outer case 101 and the single cell B. The insertion portions 150b and 150b1 are outer peripheries of the side surfaces of the adjacent single cells B facing each other and the side surfaces of the single cells B facing the side plates 105b and 105c of the outer case 101 (hereinafter also simply referred to as “opposing side surfaces”). It is inserted into only a part of the upper end of the part. Therefore, the gap S is formed at least in the central portion of the opposing side surface of the single cell B.

  The fixtures 150 </ b> A and 150 </ b> B of the present embodiment not only fix the single cell B, but also form a gap S between the adjacent single cells B and between the outer case 101 and the single cell B. Therefore, as shown by a two-dot chain line in FIG. 11, even when the side surface of the single cell B bulges during charging or the like, this can be absorbed, resulting from the bulge of each single cell B. Thus, deformation of the outer case 101 can be suppressed. Further, since the insertion portions 150b and 150b1 of the fixtures 150A and 150B are inserted into the outer peripheral portion on the opposite side surface of the single cell B, a gap S is formed corresponding to the central portion of the opposite side surface that bulges most. The bulge can be reliably absorbed by the gap S. Further, since the insertion portions 150b and 150b1 functioning as spacers are formed integrally with the fixtures 150A and 150B, the number of parts can be reduced as compared with the first embodiment. In the present embodiment, the fixtures 150A and 150B can be configured integrally with ones adjacent to each other.

  As shown in FIG. 11, the width a of the gap Sa formed between the opposing side surfaces of adjacent unit cells B is the maximum expected expansion when the opposing side surfaces of both unit cells B bulge and deform. The dimension is set to be larger than the sum of the projected dimensions. Further, the width b of the gap Sb formed between the single cell B and the side plates 105b and 105c of the outer case 101 is an estimated maximum bulging dimension when the opposing side surface of the single cell B is bulged and deformed. Is set to a larger dimension. Therefore, even if the opposing side surfaces of the single cells B bulge and deform, the adjacent single cells B and the single cells B and the side plates 105b and 105c of the outer case 101 do not contact each other. Further, due to the difference in thickness between the insertion portions 150b and 150b1, the width b of the gap Sb is formed smaller than the width a of the gap Sa, and is about ½ of the width a. By comprising in this way, the increase in the dimension of the Y direction of the exterior case 101 accompanying provision of the clearance gap S can be suppressed.

[Application of battery pack]
FIG. 12 is a schematic diagram showing an electric vehicle 200 on which the secondary battery pack 100 is mounted. In addition, although illustration is abbreviate | omitted, in order to maintain the heat insulation with the periphery, the secondary battery pack 100 is covered with a heat insulating material and the outermost case which covers it.
In the secondary battery pack 100, the vertical movement of the single cell B within the outer case 101 is restricted by the fixtures 110, 150A, and 150B described above. Therefore, the single cell B will not be lifted upward in the outer case 101 due to vibration accompanying the traveling of the electric vehicle 200.
Further, the secondary battery pack 100 is suitable as a power source for driving a main motor used for traveling or cargo handling in general electric propulsion vehicles including industrial vehicles such as forklifts in addition to electric vehicles. . Furthermore, it is suitable as a power source mounted on a moving body including a ship and an aircraft.

  Moreover, it cannot be overemphasized that the secondary battery pack 100 can be used not for a moving body but for a stationary use. Also in this case, since the secondary battery pack 100 restricts the movement of the fixture in the vertical direction of the single cell B in the outer case 101, even if the secondary battery pack 100 vibrates greatly due to an earthquake, for example, the single cell B Can be prevented.

[Others]
In the above embodiment, the secondary battery pack using the molten salt battery has been described. However, the secondary battery pack is not necessarily limited to the molten salt battery. For example, the secondary battery pack such as a lithium ion battery used in a cold region is used. The present invention is also applicable. However, the present invention is particularly effective when applied to a secondary battery pack in which the expansion of the single cell B is increased by being heated by the heater 104.
In the above embodiment, the spacer 161 and the insertion portions 150b and 150b1 are inserted between the adjacent single cells B and between the single cell B and the side plates 105b and 105c of the exterior case 101. It may be inserted between some parts. In the second embodiment, the fixtures 150A and 150B can be configured integrally with ones adjacent to each other.
The outer case 101 of the above embodiment has a configuration in which the opening 105f provided on the upper surface of the case body 105 is closed by the lid 106, but the side surface of the case body 105 (for example, the side plate 105d or (The portion provided with 105e) is used as an opening, and the opening is closed by the lid 106. A space is provided between the lid 106 and the side surface of the single cell B, and the side surface is provided on the lid 106. It may be configured to be pressed by a fixing tool. That is, in this embodiment, the secondary battery pack 100 shown in FIG. 6 is tilted sideways (rotated 90 degrees) so that the lid 106 is positioned on the side surface of the case main body 105. In this case, the fixing tool fixes the single cell B by pressing the side surface of the single cell B.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1: Positive electrode 1a: Positive electrode current collector 1b: Positive electrode material 1t: Terminal 2: Negative electrode 2a: Negative electrode current collector 2b: Negative electrode material 2t: Terminal 3: Separator 10: Molten salt battery main body 11: Battery container 100: Secondary battery Pack 101: exterior case 103: assembled battery 104: heater 105: case body 105a: bottom plate 105b: side plate 105c: side plate 105c1: insertion hole 105d: side plate 105d1: female screw hole 105e: side plate 105e1: female screw hole 105f: opening 106: lid Body 110: Fixing tool 150A: Fixing tool 150B: Fixing tool 150a: Holding part 150b: Inserting part 150b1: Inserting part 161: Spacer 161a: Notch 161b: Corner part 162: Fixing screw 163: Temperature sensor 200: Electric vehicle a: Gap width b: Gap width B: Single cell S (Sa, Sb): Gap

Claims (12)

An exterior case,
A plurality of single cells housed side by side in the exterior case;
Inserted between at least one of the unit cells adjacent to each other and between the unit cell disposed at the end of the unit cell in the arrangement direction and the side plate of the exterior case adjacent to the unit cell, And a spacer that forms a gap for absorbing bulging deformation of the side surface of the single cell.   The secondary battery pack according to claim 1, wherein the spacer forms the gap at a position corresponding to at least a central portion of the side surface of the single cell.   The side plate located at the end portion in the arrangement direction of the outer case is detachably attached to another adjacent side plate, and is attached so as to be capable of adjusting the pressing force in the arrangement direction applied to the single cells and the spacer. The secondary battery pack according to claim 1 or 2.   The secondary battery pack according to any one of claims 1 to 3, wherein the spacer is formed in an annular shape along an outer peripheral portion of a side surface of the single cell.   The secondary battery pack according to claim 4, wherein an opening is formed in a part of the spacer so as to communicate an inner peripheral side and an outer peripheral side of the spacer.   The secondary battery pack according to claim 5, wherein an electrical component is disposed in the gap, and wiring of the electrical component is drawn out to the outer peripheral side of the spacer through the opening.   The secondary battery pack according to any one of claims 4 to 6, wherein the spacer has a corner at an inner peripheral side edge, and the corner is formed in an R shape.   The said clearance gap formed between the mutually adjacent single cells has the width | variety more than the sum of the largest bulging dimension of the side surface of both single cells, The any one of Claims 1-7. Secondary battery pack.   The gap formed between the single cells at the end in the arrangement direction and the side plate of the outer case is formed between the adjacent single cells that are equal to or larger than the maximum bulging dimension of the side surface of the single cell. The secondary battery pack according to claim 8, wherein the secondary battery pack has a width smaller than the gap.   The secondary battery pack according to any one of claims 1 to 9, further comprising a heater that contacts and heats the single cell.   The outer case has an openable / closable lid, and the lid projects to the inner side of the outer case and presses the outer surface of the single cell to the single case to the outer case. The secondary battery pack according to any one of claims 1 to 10, wherein a fixing tool for fixing is provided.   A mobile body equipped with the secondary battery pack according to claim 1 as a power source.

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