JP2015011919A - Power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power unit in which a protection mechanism, operating when the internal pressure of a square battery cell rises, can be actuated quickly.SOLUTION: A power unit has a plurality of square battery cells 12 including safety means, e.g., a current interruption mechanism, being actuated when the internal pressure rises to ensure safety, and a spacer 14 provided in contact with the square battery cells 12 and insulating the square battery cells 12 from each other. The square battery cell 12 contains lithium carbonate in the positive electrode mixture layer, and a depression for allowing expansion of the square battery cell 12 is formed in the spacer 14.

Description

  The present invention relates to a power supply device including a prismatic battery cell.

  There is a power supply device in which a plurality of prismatic battery cells are juxtaposed and these battery cells are connected in series, parallel, or series-parallel to each other. Such a power supply device has a large output and is used in a hybrid electric vehicle (HEV, PHEV), an electric vehicle (EV), a large stationary power storage device, and the like.

  The battery cell expands when the internal pressure increases. When an abnormality occurs in the battery cell and the internal pressure rises, it is assumed that the battery cell breaks and causes problems such as damage to the surroundings. In order to deal with such a problem, some battery cells are provided with a protection mechanism such as a current interruption mechanism, a forced short-circuit mechanism, and a safety valve that operate when the internal pressure increases. In particular, in a nonaqueous electrolyte secondary battery, a battery in which lithium carbonate is added to a positive electrode mixture layer is known in order to operate a protection mechanism more effectively (see Patent Document 1 below). Lithium carbonate decomposes and generates carbon dioxide gas when the battery cell is overcharged and the battery voltage is increased, thereby increasing the internal pressure and quickly activating the protection mechanism.

In Patent Document 2, a pair of constraining plates that are abutted to each of the prismatic battery cells located at both ends in the juxtaposition direction among the plurality of prismatic battery cells juxtaposed are provided, There is disclosed a battery pack in which the pair of restraining plates are connected to each other by long connecting members disposed on both side ends of the rectangular battery cells so that the rectangular battery cells are pressed. .
Thereby, in the battery pack disclosed by patent document 2, it is supposed that the expansion | swelling of each square battery cell which comprises a battery pack can be prevented.

In Patent Document 3, each square battery is held at a predetermined position by a pair of holder members provided with holding parts capable of holding both ends of a plurality of prismatic battery cells arranged side by side, and between the square batteries. A plurality of rod-shaped spacers corresponding to the space have at least one spacing member arranged in a comb-like manner along the side-by-side direction of the rectangular batteries, and the rod-shaped spacers are sandwiched between the rectangular batteries, respectively. There is disclosed an assembled battery structure in which a spacing member is arranged so that a region that is not held by a holding portion in a wide surface of a rectangular battery is divided by a rod-shaped spacer.
Thereby, in the assembled battery structure disclosed in Patent Document 3, the number of components is reduced while effectively suppressing the expansion between the rectangular batteries constituting the assembled battery.

Japanese Patent Laid-Open No. 04-328278 JP 2001-236937 A JP 2012-059581 A

  In the structure that suppresses the expansion of the battery cells as disclosed in Patent Documents 2 and 3, the individual battery cells are mutually compressed in the juxtaposed direction, so that when gas is generated in the rectangular battery cells, The gas path (passage) is likely to be restricted. For this reason, the fluidity of the gas in the prismatic battery cell is lowered and the gas is likely to be trapped in a part of the prismatic battery cell, and the operation of the protection mechanism that is activated by pressure is delayed.

  According to the power supply device of one aspect of the present invention, the fluidity of the gas in the prismatic battery cell is unlikely to decrease, so that the protection mechanism that operates when the internal pressure of the prismatic battery cell increases can be quickly activated. A power supply is provided.

A power supply device according to one aspect of the present invention includes:
A plurality of prismatic battery cells comprising a positive electrode having a positive electrode mixture layer, a negative electrode having a negative electrode mixture layer, a prismatic battery outer package, and a protective mechanism that operates by increasing internal pressure to ensure safety;
A spacer, and
The plurality of prismatic battery cells are juxtaposed such that the wide surfaces of each of the prismatic battery outer bodies face each other,
The positive electrode mixture layer includes lithium carbonate,
The spacer is disposed between the wide surfaces of the rectangular battery outer bodies of the adjacent rectangular battery cells so as to contact each of the adjacent rectangular battery outer bodies, and the wide surfaces of the rectangular battery outer bodies expand. In some cases, a space is formed to allow this expanded portion.

  According to the power supply device of one aspect of the present invention, the gas fluidity in the prismatic battery cell is improved as compared with the case where the present configuration is not provided, and thus gas is generated in the prismatic battery cell. The protection mechanism that operates when the internal pressure of the battery cell suddenly increases and the internal pressure of the rectangular battery cell increases can be quickly activated.

It is a perspective view of the power supply device common to each embodiment. FIG. 2A is a plan view of a prismatic battery cell used in a power supply device common to the embodiments, and FIG. 2B is a front view of the prismatic battery cell. 3A is a sectional view taken along line IIIA-IIIA in FIG. 2A, FIG. 3B is a sectional view taken along line IIIB-IIIB in FIG. 3A, and FIG. 3C is a sectional view taken along line IIIC-IIIC in FIG. FIG. It is the schematic which looked at the spacer which concerns on 1st embodiment, and its peripheral structure. FIG. 5 is a partial schematic view of a cross section taken along line V-V in FIG. 1. It is the partial schematic of the cross section of the spacer which concerns on 2nd embodiment, and its periphery structure. It is the partial schematic of the cross section of the spacer which concerns on 3rd embodiment, and its periphery structure. It is the partial schematic of the cross section of the spacer which concerns on 4th embodiment, and its periphery structure. It is the partial schematic of the cross section of the spacer which concerns on 5th embodiment, and its periphery structure. It is the schematic which looked at the spacer which concerns on 6th embodiment, and its surrounding structure. It is the partial schematic of the cross section of the spacer which concerns on 6th Embodiment, and its periphery structure.

Hereinafter, modes for carrying out the present invention will be described. The following embodiment shows an example for embodying the technical idea of the present invention, and is not intended to limit the present invention to any of these embodiments. The present invention can be equally applied to various modifications without departing from the technical idea shown in the claims.
In the following description, the directions of “front and rear, up and down, left and right” are shown for convenience of explanation, and are not limited to these directions.

[Power supply unit]
A power supply device common to each embodiment will be described.
As shown in FIG. 1, the power supply device 10 includes a plurality of rectangular battery cells 12, a plurality of spacers 14, two end spacers 16, two end plates 18, and a bind bar 20.
The plurality of prismatic battery cells 12 are juxtaposed with each other (arranged so as to be arranged in the front-rear direction in FIG. 1), and the spacer 14 is disposed so as to be sandwiched between two adjacent prismatic battery cells 12. The end spacer 16 is disposed outside the rectangular battery cell 12 disposed at the end in the juxtaposition direction. The end plate 18 is disposed outside the end spacer 16 in the juxtaposition direction, and sandwiches the prismatic battery cell 12, the spacer 14, and the end spacer 16. The bind bar 20 fixes the square battery cell 12, the spacer 14, and the end spacer 16 so as to pressurize them in the juxtaposition direction.
Adjacent rectangular battery cells 12 are electrically connected via a bus bar 22.

  The end plate 18 has a rectangular parallelepiped shape whose outer shape (surface aligned in the juxtaposition direction) is larger than that of the prismatic battery cell 12, and is formed of a metal having a relatively high strength such as aluminum or aluminum alloy, a hard plastic, or the like. The end plate 18 may have an outer shape equivalent to that of the square battery cell 12.

  The bind bar 20 is formed of a relatively strong metal plate, such as a stainless steel plate or a steel plate. The bind bar 20 may have a shape in which an end in the vertical direction is bent. Thereby, compared with the case where this structure is not provided, the fastening strength of the power supply device 10 improves.

(Battery cell overall structure)
The details of the rectangular battery cell 12 common to each embodiment will be described.
As shown in FIGS. 2 and 3, the rectangular battery cell 12 is, for example, a rectangular nonaqueous electrolyte secondary battery, and includes a rectangular parallelepiped exterior body 30 and a sealing body 32. The exterior body 30 has two wide surfaces facing in the front-rear direction (hereinafter referred to as “wide surface 30a”) and two narrow surfaces facing in the left-right direction (hereinafter referred to as “narrow surface 30b”). And the bottom surface 30c located below, and the upper part is open. The sealing body 32 is arrange | positioned so that the opening of the exterior body 30 may be sealed. The exterior body 30 and the sealing body 32 are laser welded, and the inside of the rectangular battery cell 12 is sealed.

A positive electrode terminal 34 is fixed to the sealing body 32 via an insulating member 36, and a negative electrode terminal 38 is fixed via an insulating member 40. The bus bar 22 (see FIG. 1) is connected to the positive terminal 34 and the negative terminal 38.
The exterior body 30, the sealing body 32, and the positive electrode terminal 34 are each formed of aluminum or an aluminum alloy, and the negative electrode terminal 38 is formed of copper or a copper alloy.

  The sealing body 32 is provided with a liquid injection port 42 for injecting an electrolytic solution and a safety valve 44. The safety valve 44 discharges the gas in the rectangular battery cell 12 to the outside when the pressure in the rectangular battery cell 12 becomes a predetermined pressure or higher.

A sheet-like insulating sheet 46 made of resin is disposed inside the exterior body 30, and a flat wound electrode body 50 is disposed inside the insulating sheet 46. The flat wound electrode body 50 includes a positive electrode plate 52, a negative electrode plate 54, and a separator 56. The positive electrode plate 52 and the negative electrode plate 54 are wound in a flat shape in a state where they are insulated from each other via the separator 56. It has a rotated configuration.
The flat wound electrode body 50 is wound so that the outermost periphery is the separator 56 and the inner side is the negative electrode plate 54 and the inner side is the positive electrode plate 52 in that order. As the separator 56, for example, a microporous film made of polyolefin is used.

The positive electrode plate 52 is formed with a positive electrode mixture layer applied to both surfaces of the positive electrode core and a positive electrode core exposed portion 58. The positive electrode core exposed portion 58 is a portion where the positive electrode mixture is not applied, and is a portion where the positive electrode core is exposed in a strip shape in the winding direction of the flat wound electrode body 50.
The positive electrode core is made of, for example, aluminum or an aluminum alloy and has a thickness of about 10 to 20 μm.

The negative electrode plate 54 is formed with a negative electrode mixture layer applied to both surfaces of the negative electrode core and a negative electrode core exposed portion 60. The negative electrode core exposed portion 60 is a portion where the negative electrode mixture is not applied, and is a portion where the negative electrode core is exposed in a strip shape in the winding direction of the flat wound electrode body 50.
The formation range (width and length) of the negative electrode mixture layer is larger than the range of the positive electrode mixture layer.
The negative electrode core is made of, for example, copper or copper alloy, and has a thickness of about 5 to 15 μm.

  The flat wound electrode body 50 is arranged such that a plurality of positive electrode core exposed portions 58 overlap on one end side (right side in FIG. 3A), and the negative electrode core exposed portion 60 on the other end side (same left side). It is the structure arrange | positioned so that two or more sheets may overlap. The positive electrode plate 52 and the negative electrode plate 54 are arranged so that the positive electrode core exposed portion 58 does not overlap the layer coated with the negative electrode mixture, and the negative electrode core exposed portion 60 is a layer coated with the positive electrode mixture. It is arranged so as not to overlap.

A positive electrode current collector 62 made of aluminum or an aluminum alloy is provided outside the positive electrode core exposed portion 58.
The plurality of positive electrode core exposed portions 58 wound and laminated are converged at the center in the thickness direction and further divided into two, and the positive electrode core is centered on 1/4 of the thickness of the flat wound electrode body 50. The body exposed portion 58 is converged, and the positive electrode intermediate member 64 is disposed therebetween.
The positive electrode intermediate member 64 holds a plurality of conductive positive electrode conductive members 66, here two, on a base made of a resin material. The positive electrode conductive member 66 has a columnar shape, and a truncated cone-shaped protrusion 68 that acts as a projection is formed on the side facing each of the stacked positive electrode core exposed portions 58.

The positive electrode core exposed portion 58 is electrically connected to the positive electrode terminal 34 via the positive electrode current collector 62. A current interruption mechanism 70 is provided between the positive electrode current collector 62 and the positive electrode terminal 34. The current interrupt mechanism 70 operates to interrupt the current when the inside of the battery cell 12 becomes a predetermined pressure or higher. The current interrupt mechanism 70 is operated at a pressure lower than the pressure at which the safety valve 44 is operated.
The current interruption mechanism 70 and the safety valve 44 function as a protection mechanism that operates by increasing the internal pressure and ensures the safety of the power supply device 10 and the like.

A negative electrode current collector 72 made of copper is provided outside the negative electrode core exposed portion 60. The plurality of negative electrode core exposed portions 60 wound and laminated are converged and further divided on the center side in the thickness direction, and the negative electrode core body is centered on 1/4 of the thickness of the flat wound electrode body 50. The exposed portion 60 is converged, and the negative electrode intermediate member 74 is disposed therebetween.
The negative electrode intermediate member 74 holds a plurality of, here two, negative electrode conductive members 76 on a base made of a resin material. The negative electrode conductive member 76 has a columnar shape, and a truncated cone-shaped projection 78 that acts as a projection is formed on the side facing each of the laminated negative electrode core exposed portions.
The negative electrode core exposed portion 60 is electrically connected to the negative electrode terminal 38 via the negative electrode current collector 72.

  Resistance welding method between the positive electrode current collector 62, the positive electrode core exposed portion 58, and the positive electrode conductive member 66 of the positive electrode intermediate member 64, and the negative electrode current collector 72, the negative electrode core exposed portion 60, As a resistance welding method between the negative electrode intermediate member 74 and the negative electrode conductive member 76, a well-known technique is used.

  Next, the manufacturing method of the rectangular battery cell 12 will be described in detail.

(Configuration of positive electrode plate)
As the positive electrode plate 52, for example, one produced as follows is used.
As the positive electrode active material, a lithium nickel cobalt manganese composite oxide represented by LiNi _0.35 Co _0.35 Mn _0.30 O ₂ is used. A positive electrode mixture containing lithium nickel cobalt manganese composite oxide, carbon powder as a conductive agent, polyvinylidene fluoride (PVdF) as a binder, and lithium carbonate, and N-methyl-2-2 as a dispersion medium A positive electrode slurry is prepared by mixing pyrrolidone (NMP).

  The lithium nickel cobalt manganese composite oxide, the carbon powder, and PVdF are contained so as to have a mass ratio of 88: 9: 3, respectively. The lithium carbonate is preferably contained in an amount of 0.1 to 5.0% by mass with respect to the positive electrode mixture. When the content of lithium carbonate in the positive electrode mixture is less than 0.1% by mass, the generation of carbon dioxide from the lithium carbonate is small and it is difficult to quickly activate the protection mechanism. When the content of lithium carbonate in the positive electrode mixture exceeds 5.0% by mass, the proportion of lithium carbonate not involved in the electrode reaction is excessively increased, and the battery capacity is greatly reduced.

  This positive electrode slurry is applied to both surfaces of the positive electrode core by a die coater, and a positive electrode mixture layer is formed on both surfaces of the positive electrode core. Next, it is dried to remove NMP, and compressed to a predetermined thickness by a roll press. After cutting out to a predetermined dimension, a part of the positive electrode mixture layer is removed so as to form the positive electrode core body exposed portion 58 over the entire length direction (winding direction) on one end side in the width direction.

(Configuration of negative electrode plate)
As the negative electrode plate 54, for example, one produced as follows is used.
A negative electrode slurry containing graphite powder, carboxymethyl cellulose (CMC) as a thickener, and styrene-butadiene rubber (SBR) as a binder is dispersed in water to prepare a negative electrode slurry. The graphite powder, CMC, and SBR are contained so as to have a mass ratio of 98: 1: 1, respectively.

  This negative electrode slurry is applied to both surfaces of the negative electrode core by a die coater to form a negative electrode mixture layer on both surfaces of the negative electrode core. Subsequently, it compresses so that it may become predetermined thickness using a compression roller. After cutting out to a fixed dimension, a part of negative electrode mixture layer is removed so that the negative electrode core exposed part 60 covering the whole length direction (winding direction) may be formed in the one end side of the width direction.

(Preparation of non-aqueous electrolyte)
As the nonaqueous electrolytic solution, for example, one prepared as follows is used.
LiPF ₆ as an electrolyte salt is added to a mixed solvent in which ethylene carbonate (EC) and methyl ethyl carbonate (MEC) are mixed at a volume ratio (25 ° C., 1 atm) in a ratio of 3: 7 so as to be 1 mol / L. To do.

(Preparation of prismatic battery cell)
The square battery cell 12 is produced as follows, for example.
The positive electrode plate 52 and the negative electrode plate 54 are wound so that they are insulated from each other via the separator 56 so that the outermost surface becomes the negative electrode plate 54, and then are formed into a flat shape to form a flat wound electrode body. 50 is produced. After the flat wound electrode body 50 is accommodated in the exterior body 30, the sealing body 32 is fitted into the opening of the exterior body 30, and laser welding is performed between the exterior body 30 and the sealing body 32. Next, a predetermined amount of nonaqueous electrolytic solution is injected from the injection port 42. Then, the liquid injection port 42 is sealed with a blind rivet.

[First embodiment]
(Spacer)
Next, the detail of the spacer 14 regarding embodiment is demonstrated.
As shown in FIGS. 4 and 5, the spacer 14 holds the plurality of prismatic battery cells 12 apart from each other and prevents the prismatic battery cells 12 from short-circuiting. The spacer 14 is disposed between the wide surfaces 30 a of the adjacent rectangular battery cells 12 so as to come into contact with each of the adjacent rectangular battery outer bodies 30. The spacer 14 has an insulating property and is designed to have a strength that does not damage even if it is sandwiched between the rectangular battery cells 12 and the like. The spacer 14 is formed of, for example, nylon resin, epoxy resin, plastic such as polyethylene terephthalate, or the like.

  The spacer 14 has an outer shape (surface aligned in the juxtaposition direction) of the same size as the prismatic battery cell 12. A contact portion 82 corresponding to the edge of the wide surface 30a of the rectangular battery cell 12 and a recessed portion 84 that is recessed toward the center in the front-rear direction of the spacer 14 from the contact portion 82 are formed on the front-rear surface 14a of the spacer 14. Is formed.

The contact portion 82 is formed in a frame shape, and comes into contact with the rectangular battery cell 12 outside the portion where the flat wound electrode body 50 of the rectangular battery cell 12 is disposed.
The hollow portion 84 functions as a space portion that allows the expanded portion when the rectangular battery cell 12 expands. The depression 84 is formed so that the distance between the positive electrode plate 52 and the negative electrode plate 54 increases when gas is generated from the flat wound electrode body 50. Specifically, the recess 84 is formed at a position facing the flat wound electrode body 50 of the rectangular battery cell 12. The depression 84 has a shape (a shape having a substantially uniform depth) that is recessed at an equal distance from the contact portion 82.

The depth (distance recessed from the contact portion 82) d of the recessed portion 84 is, for example, about 3 to 20%, preferably about 5 to 10% of the length (thickness) T in the front-rear direction of the spacer 14.
For example, when the size of the wide surface 30a of the rectangular battery cell 12 is 90 mm × 150 mm and the thickness T of the spacer 14 is 3 to 5 mm, the depth d of the recess 84 is 0.1 to 0.5 mm, Preferably, it is about 0.2 to 0.4 mm.

The prismatic battery cell 12 is likely to expand on the wide surface 30a side, and in particular, the expansion at a position facing the flat wound electrode body 50 increases.
In the present embodiment, the spacer 14 comes into contact with the prismatic battery cell 12 at a position not facing the flat wound electrode body 50. For this reason, in the square battery cell 12 of this embodiment, it becomes difficult to inhibit the expansion | swelling of the square battery cell 12 compared with the case where it does not have such a structure. Since the expansion of the prismatic battery cell 12 (the outer package 30) is difficult to be inhibited, the distance between the positive electrode plate 52 and the negative electrode plate 54 of the flat wound electrode body 50 is likely to increase. For this reason, the fall of the fluidity | liquidity of the gas which generate | occur | produces in the square battery cell 12 is suppressed.

  Therefore, when an abnormality occurs in the prismatic battery cell 12 during overcharge or the like, the carbon dioxide gas generated by the decomposition of lithium carbonate rapidly moves in the prismatic battery cell 12 to increase the pressure in the prismatic battery cell 12. When this pressure exceeds a predetermined pressure, the current interruption mechanism 70 is quickly activated. Thereby, since the overcharged state with respect to the rectangular battery cell 12 is eliminated, the generation of gas in the rectangular battery cell 12 is stopped, and the increase of the internal pressure is also stopped.

The end spacer 16 is configured in the same manner as the spacer 14 except that the contact portion 82 and the depression 84 are formed on one side of the surface 16a on the prismatic battery cell 12 side. The length (thickness) of the end spacer 16 in the front-rear direction may be the same as that of the spacer 14 or may be changed as appropriate.
The size and depth of the recess 84 can be appropriately set according to the characteristics of the power supply device 10 and the rectangular battery cell 12.

[Second Embodiment]
Next, a second embodiment will be described.
In the first embodiment, the recess 14 and the end spacer 16 are formed with the recessed portion 84 having a recessed shape at an equal distance from the contact portion 82, whereas in the second embodiment, the recessed portion is formed. They are different in that 92 is formed. About 2nd embodiment, about the member substantially the same as 1st embodiment, the same referential mark is provided and the detailed description is abbreviate | omitted.

As shown in FIG. 6, in the second embodiment, on the front surface 14 a of the spacer 14, a contact portion 82, and a hollow portion 92 that is recessed toward the center in the front and rear direction of the spacer 14 with respect to the contact portion 82. Is formed.
The recess 92 functions as a space that allows the expanded portion when the rectangular battery cell 12 expands. The recess 92 is formed so that the distance between the positive electrode plate 52 and the negative electrode plate 54 is increased when gas is generated from the flat wound electrode body 50. Specifically, the recess 92 is formed at a position facing the flat wound electrode body 50 of the rectangular battery cell 12. The depression 92 has a shape that is recessed in a curved shape toward the center of the spacer 14 in the vertical and horizontal directions.

  The prismatic battery cell 12 tends to expand toward the center of the wide surface 30a in the vertical and horizontal directions. The hollow portion 92 has a shape closer to the shape when the rectangular battery cell 12 expands. For this reason, compared with the case where it does not have this structure, the part which is hard to contribute to accept | permitting expansion | swelling of the square battery cell 12 is reduced, and the ratio (volume) which the main-body part of the spacer 14 occupies increases. Therefore, the insulating property and strength of the spacer 14 are improved.

The end spacer 16 has a contact portion 82 and a recessed portion 92 formed on one surface 16a on the prismatic battery cell 12 side.
The recess 92 is not limited to a shape that is curved in a curved shape toward the center in the vertical and horizontal directions, but a shape that is curved in a curved shape toward the vertical center so as to be uniform in the horizontal direction, that is, a cylinder. A cut shape (harp pipe shape) may be used. The size and depth of the recess 92 can be set as appropriate according to the characteristics of the power supply device 10 and the rectangular battery cell 12.

[Third embodiment]
Next, a third embodiment will be described.
In the first embodiment, the recesses 84 are formed in the spacer 14 and the end spacer 16 so as to be recessed at an equal distance from the contact portion 82, whereas in the third embodiment, the recesses are formed. They are different in that 94 is formed. About 3rd embodiment, about the member substantially the same as 1st embodiment, the same referential mark is provided and the detailed description is abbreviate | omitted.

  As shown in FIG. 7, in the third embodiment, the front surface 14 a of the spacer 14 has a contact portion 82, and a hollow portion 94 that is recessed toward the center in the front and rear direction of the spacer 14 relative to the contact portion 82. Is formed.

  The hollow portion 94 functions as a space portion that allows the expanded portion when the rectangular battery cell 12 expands. The recess 94 is formed so that the distance between the positive electrode plate 52 and the negative electrode plate 54 is increased when gas is generated from the flat wound electrode body 50. Specifically, the recess 94 is formed at a position facing the flat wound electrode body 50 of the prismatic battery cell 12. The recess 94 has a shape that is recessed toward the center of the spacer 14 in the vertical and horizontal directions. The recessed portion 94 is configured by a first recess 94a having a shape recessed at an equal distance from the contact portion 82 and a second recess 94b having a shape recessed at an equal distance from the first recess 94a. The

  The prismatic battery cell 12 tends to expand toward the center of the wide surface 30a in the vertical and horizontal directions. The depression 94 has a shape closer to the shape when the rectangular battery cell 12 is expanded. For this reason, compared with the case where it does not have this structure, the part which is hard to contribute to accept | permitting expansion | swelling of the square battery cell 12 is reduced, and the ratio (volume) which the main-body part of the spacer 14 occupies increases. Therefore, the insulating property and strength of the spacer 14 are improved.

The end spacer 16 has a contact portion 82 and a recessed portion 92 formed on one surface 16a on the prismatic battery cell 12 side.
The hollow portion 94 is not limited to the configuration in which the first concave portion 94a and the second concave portion 94b are dented in two stages, and can be appropriately set to have three or more stages. The size and depth of the hollow portion 94 can be set as appropriate according to the characteristics of the power supply device 10 and the rectangular battery cell 12.

[Fourth embodiment]
Next, a fourth embodiment will be described.
In the first embodiment, the recesses 84 are formed in the spacer 14 and the end spacer 16 so as to be recessed at an equal distance from the contact portion 82, whereas in the fourth embodiment, the recesses are formed. They are different in that 96 is formed. In the fourth embodiment, members substantially the same as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIG. 8, in the fourth embodiment, on the front surface 14 a of the spacer 14, a contact portion 82 and a hollow portion 96 that is recessed more in the front-rear direction center side of the spacer 14 than the contact portion 82. And are formed.

  The hollow portion 96 functions as a space portion that allows the expanded portion when the rectangular battery cell 12 expands. The hollow portion 96 is formed so that the distance between the positive electrode plate 52 and the negative electrode plate 54 increases when gas is generated from the flat wound electrode body 50. Specifically, the recess 96 is formed at a position facing the flat wound electrode body 50 of the rectangular battery cell 12. The hollow portion 96 is substantially parallel to the contact portion 82 and is formed in a rectangular plane 96a formed on the center side in the front-rear direction from the contact portion 82, and an inclined surface 96b inclined from the contact portion 82 toward the four surfaces of the plane 96a. It consists of.

  The prismatic battery cell 12 tends to expand toward the center of the wide surface 30a in the vertical and horizontal directions. The hollow portion 96 has a shape closer to the shape when the rectangular battery cell 12 expands. For this reason, compared with the case where it does not have this structure, the part which is hard to contribute to accept | permitting expansion | swelling of the square battery cell 12 is reduced, and the ratio (volume) which the main-body part of the spacer 14 occupies increases. Therefore, the insulating property and strength of the spacer 14 are improved.

The end spacer 16 has a contact portion 82 and a recess 96 formed on one side of the surface 16a on the prismatic battery cell 12 side. The recess 96 has an inclined surface 96b formed toward the four sides of the plane 96a. However, the inclined surface 96b may be formed so as to be directed to two sides in the vertical direction or two sides in the horizontal direction. The size and depth of the recess 96 can be appropriately set according to the characteristics of the power supply device 10 and the rectangular battery cell 12.

[Fifth embodiment]
Next, a fifth embodiment will be described.
In the first embodiment, the recessed portion 84 is formed in the spacer 14 so as to be recessed at an equal distance from the contact portion 82, whereas in the fifth embodiment, the recessed portion 98 is formed. Are different from each other. About 5th embodiment, about the member substantially the same as 1st embodiment, the same referential mark is provided and the detailed description is abbreviate | omitted.

  As shown in FIG. 9, in the fifth embodiment, the front surface 14 a of the spacer 14 has a contact portion 82, and a recessed portion 98 that is recessed toward the center in the front-rear direction of the spacer 14 with respect to the contact portion 82. Is formed.

  The hollow portion 98 functions as a space portion that allows the expanded portion when the rectangular battery cell 12 expands. The recess 98 is formed so that the distance between the positive electrode plate 52 and the negative electrode plate 54 is increased when gas is generated from the flat wound electrode body 50. Specifically, the recess 98 is formed at a position facing the flat wound electrode body 50 of the rectangular battery cell 12. The hollow portion 98 includes an opening 98a formed so as to penetrate the spacer 14, and an insulating member 98b provided so as to close the opening 98a. The insulating member 98b is formed of, for example, an insulating film or an insulating plate.

The depth of the recessed portion 98 with respect to the front-rear direction is greater than when the configuration is not provided. For this reason, in the hollow part 98, the expansion | swelling of the square battery cell 12 accept | permitted with respect to a stacking direction (front-back direction) becomes large. Further, since the insulating member 98b is arranged so as to close the opening 98a, it is possible to prevent the adjacent rectangular battery cells 12 from coming into contact with each other and eventually short-circuiting.
The size of the recess 98 can be appropriately set according to the characteristics of the power supply device 10 and the rectangular battery cell 12.

[Sixth embodiment]
Next, a sixth embodiment will be described.
In the first embodiment, the contact portion 82 and the recess portion 84 are formed in the spacer 14 and the end spacer 16, whereas in the sixth embodiment, the contact portion 102 and the recess portion 104 are formed. In that they are different. In the sixth embodiment, members substantially the same as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIGS. 10 and 11, in the sixth embodiment, the surface 14a in the front-rear direction of the spacer 14 corresponds to the edge of the wide surface 30a of the prismatic battery cell 12 and the vicinity of the prismatic battery cell 12 and the lower part thereof. Are formed, and a recessed portion 104 that is recessed toward the center in the front-rear direction of the spacer 14 with respect to the contact portion 102 is formed.

  The contact portion 102 is configured such that a frame-shaped portion 102a formed in a frame shape and a plate-shaped portion 102b arranged in a plurality (three in this embodiment) in the vertical direction of the spacer 14 and extending in the horizontal direction are coupled. Has been.

  The depression 104 functions as a space that allows the expanded portion when the rectangular battery cell 12 expands. The depression 104 is formed so that the distance between the positive electrode plate 52 and the negative electrode plate 54 is widened when gas is generated from the flat wound electrode body 50. Specifically, the recess 104 is formed at a position facing the flat wound electrode body 50 of the rectangular battery cell 12. A plurality of depressions 104 are provided (four in this embodiment) so as to sandwich the plate-like portion 102b in the vertical direction, and the depressions 104 have a shape that is recessed at an equal distance from the contact portion 102 (a shape that has a uniform depth). ing.

In the sixth embodiment, the spacer 14 is formed in a comb shape, and is in contact with the prismatic battery cell 12 as compared with the case where the frame-shaped member 102a, the plate-shaped member 102b, and the plurality of hollow portions 104 are not formed. Small area to do. For this reason, compared with the case where the spacer 14 contacts the whole wide surface 30a of the square battery cell 12, it becomes difficult to inhibit expansion | swelling of the square battery cell 12. FIG. Specifically, when the rectangular battery cell 12 expands, the expanded portion expands toward the plurality of depressions 104. In particular, when the outer package 30 of the prismatic battery cell 12 is formed of a flexible material such as aluminum, the expanded portion is easily dispersed and spreads in the plurality of depressions 104 (deforms into a wave shape). In this way, a decrease in fluidity of the gas generated in the rectangular battery cell 12 is suppressed.
On the other hand, it contacts with the square battery cell 12 inside the edge of the wide surface 30a. For this reason, the prismatic battery cells 12 juxtaposed are more stably fixed. Moreover, since the ratio (volume) which the main-body part of the spacer 14 occupies increases, the insulation property and intensity | strength of this spacer 14 improve more.

The end spacer 16 has a contact portion 102 and a recessed portion 104 formed on one surface 16a on the prismatic battery cell 12 side.
The contact portion 102 is not limited to forming the plate-like portion 102b extending in the left-right direction, and may extend in the up-down direction. Further, four depressions 104 may be formed so as to extend in the vertical and horizontal directions (cross shape, cross shape). The size and depth of the recess 102 can be appropriately set according to the characteristics of the power supply device 10 and the rectangular battery cell 12.

  About the spacer 14, you may make it combine 1st embodiment-6th embodiment suitably according to design property, workability, etc. FIG.

  The power supply device 10 can be suitably used for an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and the like. It is also used for backup power supply devices mounted on computer server racks, backup power supply devices for wireless base stations such as mobile phones, power storage devices for household use or factories, and power storage devices combined with solar cells. Available.

DESCRIPTION OF SYMBOLS 10 ... Power supply device 12 ... Battery cell 14 ... Spacer 16 ... End spacer 18 ... End plate 20 ... Bind bar 22 ... Bus bar 30 ... Exterior body 32 ... Sealing body 34 ... Positive electrode terminal 38 ... Negative electrode terminal 42 ... Injection port 44 ... Safety valve DESCRIPTION OF SYMBOLS 50 ... Flat winding electrode body 52 ... Positive electrode plate 54 ... Negative electrode plate 56 ... Separator 58 ... Positive electrode core exposed part 60 ... Negative electrode core exposed part 62 ... Positive electrode collector 70 ... Current interruption | blocking mechanism 72 ... Negative electrode collector 82 ... contact part 84 ... hollow part

Claims (8)

A plurality of prismatic battery cells comprising a positive electrode having a positive electrode mixture layer, a negative electrode having a negative electrode mixture layer, a prismatic battery outer package, and a protective mechanism that operates by increasing internal pressure to ensure safety;
A spacer;
Have
The plurality of prismatic battery cells are juxtaposed such that the wide surfaces of each of the prismatic battery outer bodies face each other,
The positive electrode mixture layer includes lithium carbonate,
The spacer is disposed between the wide surfaces of the rectangular battery outer bodies of the adjacent rectangular battery cells so as to contact each of the adjacent rectangular battery outer bodies, and the wide surfaces of the rectangular battery outer bodies expand. When this is done, a space is formed to allow this expanded part.
Power supply. The rectangular battery cell comprises a flat wound electrode body in which a positive electrode plate and a negative electrode plate are wound,
2. The power supply device according to claim 1, wherein when the gas is generated from the wound electrode body, the spacer has the space portion formed so that a distance between the positive electrode plate and the negative electrode plate is widened.   The spacer has a frame-shaped contact portion formed at a position corresponding to an edge of the wide surface of the rectangular battery outer casing, and is in contact with the rectangular battery outer casing at the frame-shaped contact portion. 2. The power supply device according to 2.   The power supply device according to claim 1, wherein the rectangular battery cell is a non-aqueous electrolyte secondary battery.   The power supply device according to any one of claims 2 to 4, wherein the spacer has the space formed at a position facing the spirally wound electrode body.   The power supply device according to claim 2, wherein the spacer is in contact with the rectangular battery cell at a position not facing the spirally wound electrode body.   The power supply device according to any one of claims 1 to 6, wherein the rectangular battery case is made of aluminum or an aluminum alloy.   End plates are respectively disposed on the wide surfaces of the both ends of the plurality of arranged prismatic battery cells, and the end plates mutually press the plurality of prismatic battery cells in the juxtaposing direction with a bind bar. However, the power supply device according to claim 1, wherein the power supply device is integrally fastened.

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