WO2019244413A1

WO2019244413A1 - Battery pack

Info

Publication number: WO2019244413A1
Application number: PCT/JP2019/008086
Authority: WO
Inventors: 孝行中島; 政文志波
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-06-19
Filing date: 2019-03-01
Publication date: 2019-12-26
Also published as: JPWO2019244413A1; JP7023359B2

Abstract

The present disclosure addresses the problem of providing a battery pack which can prevent the short-circuiting of upper and lower battery cells caused by an electrolyte leaked when a safety valve provided in the battery cell is opened. The solution is a battery pack including a plurality of flat rectangular battery cells 1 and a plurality of cell holders 22. The battery cell 1 has a safety valve 1v on one end surface 1a thereof along the thickness direction Dt. The cell holder 22 has an extension portion 221 extending in the thickness direction Dt toward the safety valve 1v along the one end surface 1a of the battery cell 1 and extending in a direction perpendicular to the thickness direction Dt along the one end surface 1a. A recessed gap portion 222 is formed between the one end surface 1a of the battery cell 1 and an end surface 221a of the extension portion 221 opposite to the one end surface 1a.

Description

Battery pack

The present disclosure relates to a battery pack including a plurality of battery cells.

2. Description of the Related Art Conventionally, there has been known an invention relating to a battery pack in which a plurality of prismatic batteries are connected in series and / or in parallel, and particularly to a battery pack used in a battery-powered vehicle such as a hybrid vehicle (HEV) and an electric vehicle (PEV) ( See Patent Document 1 below). The main object of the invention described in Patent Document 1 is to provide a battery pack in which the insulation between adjacent rectangular battery cells is enhanced (see Paragraph 0006 of the document). As means for achieving this object, Patent Literature 1 discloses a battery pack having the following configuration.

The battery pack described in Patent Literature 1 has a plurality of battery cells each housed in a rectangular outer can and a plurality of insulating and heat insulating properties covering the outer periphery of the outer can except for the electrode terminals of the battery cells. And a separator. Each separator is interposed between the battery cells so as to contact the outer can of the battery cell on both surfaces thereof, and exposes the electrode terminals in a state where the outer can of the battery cell is covered with the separator, and this portion is connected. (See the same document, claim 1 etc.).

That is, in this conventional battery pack, a plurality of flat rectangular battery cells are stacked in the thickness direction via a separator. The rectangular battery cell has electrode terminals at both ends in the longitudinal direction of an elongated rectangular end face parallel to the stacking direction, and has a safety valve at the center of the end face. The safety valve is a valve that opens when the internal pressure of the battery cell rises abnormally and discharges the gas inside the battery cell to the outside (see the same document, paragraph 0031, FIG. 2, etc.).

JP 2008-166191 A

In a battery pack, a plurality of battery cells may be stacked in a vertical direction due to space restrictions, for example. In this case, since the battery cells are arranged vertically adjacent to each other, when the safety valve provided on the battery cell arranged above is opened, the electrolyte leaking from the safety valve flows downward, and the electrolyte causes the electrolyte solution to flow upward and downward. The battery cell may be short-circuited.

The present disclosure provides a battery pack capable of preventing a short circuit between upper and lower battery cells due to an electrolyte leaking when a safety valve provided on a battery cell is opened.

One embodiment of the present disclosure includes a plurality of flat rectangular battery cells, and a plurality of cell holders that hold the battery cells from both sides in the thickness direction and stack the plurality of battery cells in the thickness direction. A battery pack, wherein the battery cell has a safety valve on one end surface along the thickness direction, and the cell holder extends in the thickness direction toward the safety valve along the one end surface of the battery cell. And having an extending portion extending in a direction orthogonal to the thickness direction along the one end surface, between the one end surface of the battery cell and the end surface of the extending portion opposite to the one end surface, A battery pack having a concave void portion.

According to one embodiment of the present disclosure, it is possible to provide a battery pack that can prevent a short circuit between upper and lower battery cells due to an electrolyte leaking when a safety valve provided on a battery cell is opened.

1 is an external perspective view of a battery pack according to an embodiment of the present disclosure. FIG. 2 is an exploded perspective view showing a state where a cover of a housing of the battery pack shown in FIG. 1 is removed. FIG. 3 is an exemplary perspective view of a battery module housed in a housing of the battery pack illustrated in FIG. 2; FIG. 4 is an exemplary perspective view of a part of the battery module from which the bus bar case illustrated in FIG. 3 is removed; FIG. 5 is a sectional view of a part of the battery module along the line VV in FIG. 4. FIG. 6 is an enlarged sectional view of a part of the battery module shown in FIG. 5. FIG. 3 is an exemplary perspective view of an electrical component holder accommodated in a housing of the battery pack illustrated in FIG. 2; FIG. 8 is a perspective view of the electrical component holder illustrated in FIG. 7 when viewed from an opposite direction. FIG. 6 is an enlarged sectional view showing a modification of the cell holder shown in FIG. 5. FIG. 6 is an enlarged sectional view showing a modification of the cell holder shown in FIG. 5.

Hereinafter, embodiments of the battery pack according to the present disclosure will be described with reference to the drawings. Note that directions such as up and down, front and rear, and left and right in the following description are directions for describing each part shown in the drawings, and do not limit the directions when the battery pack is used.

FIG. 1 is an external perspective view of a battery pack 100 according to an embodiment of the present disclosure. FIG. 2 is an exploded perspective view of the battery pack 100 shown in FIG. 1 with the cover 12 of the housing 10 removed. FIG. 3 is a perspective view of the battery module 20 housed in the housing 10 of the battery pack 100 shown in FIG. FIG. 4 is a perspective view of a part of the battery module 20 from which the bus bar 21 and the bus bar case 26 shown in FIG. 3 are removed.

FIG. 5 is a cross-sectional view of a part of the battery module 20 along the line VV shown in FIG. FIG. 6 is an enlarged sectional view of a part of the battery module 20 shown in FIG. 5 and 6 are partial cross-sectional views showing a state in which each part except for the battery cell 1 is cut without cutting the battery cell 1. The battery pack 100 of the present embodiment is mounted on, for example, a vehicle such as an electric vehicle or a hybrid vehicle, stores electric power supplied from electric devices of the vehicle, and supplies the stored electric power to electric devices of the vehicle.

Although the details will be described later, the main feature of the battery pack 100 of the present embodiment is that it has the following configuration. The battery pack 100 includes a plurality of flat rectangular battery cells 1 and a plurality of cell holders 22 that hold the battery cells 1 from both sides in the thickness direction Dt and stack the plurality of battery cells 1 in the thickness direction Dt. Have. The battery cell 1 has a safety valve 1v on one end face 1a along the thickness direction Dt. The cell holder 22 has an extending portion 221 extending along the one end surface 1a of the battery cell 1 in the thickness direction Dt toward the safety valve 1v and extending along the one end surface 1a in a direction orthogonal to the thickness direction Dt. ing. Further, a concave void portion 222 is formed between one end surface 1a of the battery cell 1 and an end surface 221a of the extending portion 221 opposite to the one end surface 1a.

Hereinafter, each configuration of the battery pack 100 of the present embodiment will be described in detail. The battery pack 100 of the present embodiment includes, for example, a housing 10, a battery module 20, and an electrical component holder 30. The housing 10 has, for example, a substantially rectangular parallelepiped shape, and a dimension in the front and rear depth direction is larger than a dimension in the vertical direction, and a dimension in the left and right width directions is larger than the dimension in the depth direction. .

The housing 10 has, for example, a rectangular box-shaped main body 11 whose upper part is open, and a lid-like cover 12 that closes the upper opening of the main body 11. The main body 11 houses the battery module 20 on the rear side in the depth direction, and houses the electrical component holder 30 on the front side in the depth direction.

The cover 12 has, for example, a recess at the corners at both ends in the width direction at the front end in the depth direction, and an opening at the recess. In the battery pack 100, a pair of high-voltage terminals 101, which are external terminals, are exposed from the housing 10 by an opening provided in a concave portion of the cover 12. The battery pack 100 is supplied with power from an external device via the high voltage terminal 101, and supplies power to the external device via the high voltage terminal 101.

{Circle around (2)} The cover 12 has, for example, a concave portion on the rear side of the right front corner where the high-voltage terminal 101 is arranged, and an opening for exposing the signal connector 102 is formed in the concave portion. In the battery pack 100, the signal connector 102 is exposed from the housing 10 by an opening provided in the concave portion of the cover 12. Battery pack 100 is connected via signal connector 102 to, for example, an electronic control unit mounted on a vehicle. The signal connector 102 is, for example, a connector for a control signal of the battery pack 100, and inputs and outputs information and receives power.

The battery module 20 is housed, for example, on the rear side in the depth direction inside the housing 10 and is fixed to the housing 10 by a fastening member such as a bolt. The battery module 20 includes a plurality of flat rectangular battery cells 1 and a plurality of cell holders 22 that hold the battery cells 1 from both sides in the thickness direction Dt and stack the plurality of battery cells 1 in the thickness direction Dt. Have.

The battery module 20 includes, for example, a bus bar 21 that connects the plurality of battery cells 1, a pair of end plates 23 disposed at both ends in the stacking direction of the plurality of battery cells 1, and a width direction of the plurality of battery cells 1. Dw and a pair of side blocks 24 arranged at both left and right ends of Dw. Furthermore, the battery module 20 faces, for example, a center block 25 arranged between the battery cells 1 arranged on the left and right in the width direction Dw, and one end surface 1a of the plurality of battery cells 1 along the thickness direction Dt. And a busbar case 26 to be arranged.

As described above, the battery pack 100 of the present embodiment includes the housing 10 that houses the plurality of battery cells 1, and the plurality of battery cells 1 are stacked, for example, in a direction perpendicular to the bottom wall 10 b of the housing 10. Is done. Battery cell 1 is, for example, a prismatic lithium ion secondary battery. As shown in FIGS. 4 and 5, the battery cell 1 has a substantially rectangular parallelepiped flat shape. The battery cell 1 is connected to a flat rectangular battery can 1c, a battery lid 1d for closing an opening of the battery can 1c, an electrode group 1e and an electrolyte 1f housed in the battery can 1c, and the electrode group 1e. And a pair of external terminals 1g attached to the battery lid 1d.

The battery lid 1d is, for example, a substantially rectangular plate-shaped member, and is hermetically sealed to the opening of the battery can 1c by laser welding over the entire circumference. The battery can 1c and the battery lid 1d constitute a battery container that contains and seals the electrode group 1e and the electrolyte 1f. The outer surface of the battery lid 1d is one end surface 1a along the thickness direction Dt of the battery cell 1 having the safety valve 1v.

The battery lid 1d has a pair of external terminals 1g arranged at both longitudinal ends of an outer surface that is one end surface 1a of the battery cell 1, and a safety valve 1v is provided between the pair of external terminals 1g. In the present embodiment, the longitudinal direction of one end surface 1a of the battery cell 1 may be referred to as the width direction Dw of the battery cell 1, and the width direction Dw of the battery cell 1 may be simply referred to as the "width direction Dw".

The safety valve 1v is provided on the battery lid 1d by, for example, forming a groove-shaped slit by thinning a part of the battery lid 1d. The safety valve 1v is, for example, a gas discharge valve that is opened when the internal pressure of the battery cell 1 rises abnormally and releases the gas inside the battery cell 1 to reduce the internal pressure of the battery cell 1. Further, the safety valve 1v may be provided, for example, by joining a cleavage plate configured to be cleaved at a predetermined pressure to an opening of the battery lid 1d.

The electrode group 1e is, for example, a wound electrode group in which a long strip-shaped positive electrode and a long strip-shaped negative electrode are wound opposite to each other via a separator that is a long strip-shaped insulating member. The positive electrode forming the electrode group 1e is connected to the positive external terminal 1g via the positive current collector 1h, for example. The negative electrode included in the electrode group 1e is connected to the negative external terminal 1g via the negative current collector 1h, for example.

The electrolyte 1f is housed in the battery can 1c by being injected into the inside of the battery can 1c from a liquid inlet provided in the battery lid 1d, for example, and is impregnated in the electrode group 1e. After injecting the electrolyte 1f, the battery can 1c is sealed by the battery lid 1d of the battery cell 1 by, for example, joining the injection plug 1k to the injection port of the battery lid 1d by laser welding.

One of the pair of external terminals 1g of the battery cell 1 is a positive external terminal 1g connected to a positive electrode forming the electrode group 1e, and the other is a negative external terminal connected to a negative electrode forming the electrode group 1e. External terminal 1g. The external terminal 1g is electrically insulated from the battery lid 1d by, for example, a gasket or an insulating member. The external terminal 1g has, for example, a connection portion that penetrates through the battery lid 1d, the gasket, and the insulating member and is connected to the current collector 1h.

The current collector plate 1h of the positive electrode is fixed to one end in the longitudinal direction of the one end face 1a via an insulating member, for example, by plastically deforming and crimping the end of the connection portion of the external terminal 1g of the positive electrode, The positive electrode constituting the electrode group 1e is bonded to the metal foil laminated portion of the positive electrode by ultrasonic bonding. Similarly, the current collector plate 1h of the negative electrode is, for example, plastically deformed at the end of the connection portion of the external terminal 1g of the negative electrode and caulked, so that the other end of the one end surface 1a in the longitudinal direction is interposed via the insulating member. It is fixed and bonded to the metal foil laminated portion of the negative electrode constituting the electrode group 1e by ultrasonic bonding.

二つ Two battery cells 1 adjacent to each other in the stacking direction, which is the thickness direction Dt, are alternately inverted by 180 ° so that the external terminals 1g having different polarities are adjacent to each other in the stacking direction. Then, by connecting the external terminals 1g having different polarities of the adjacent battery cells 1 sequentially in the stacking direction by the bus bar 21 shown in FIG. 3, the stacked battery cells 1 are connected in series. Can be.

The bus bar 21 is, for example, a metal plate-shaped member having a conductive property such as aluminum or copper, and is joined to the external terminal 1g of the battery cell 1 by laser welding or ultrasonic joining, and The terminals 1g are electrically connected.

において In the battery pack 100 of the present embodiment, the battery module 20 has two battery rows each including a plurality of flat rectangular battery cells 1 stacked in the thickness direction Dt, as shown in FIG. The two battery rows in which the battery cells 1 are stacked in the thickness direction Dt are arranged on the left and right in the width direction Dw of the battery cells 1.

In the battery cell 1 arranged at the top of the right battery row shown in FIG. 4, the left positive external terminal 1g of the pair of external terminals 1g is connected to the end bus bar 21a shown in FIG. . In the battery cell 1 arranged at the bottom of the right battery row shown in FIG. 4, the left external terminal 1g of the pair of external terminals 1g is connected to the intermediate bus bar 21b shown in FIG. I have.

In the battery cell 1 arranged at the bottom of the left battery row shown in FIG. 4, the right positive external terminal 1g of the pair of external terminals 1g is connected to the intermediate bus bar 21b shown in FIG. I have. Further, in the battery cell 1 arranged at the uppermost stage of the battery row on the left side shown in FIG. 4, the external terminal 1g on the right side of the pair of external terminals 1g is connected to the end bus bar 21c shown in FIG. ing.

That is, in the examples shown in FIGS. 3 and 4, the battery cells 1 from the uppermost row to the lowermost row constituting the right battery row and the battery cells 1 from the lowermost row to the uppermost row of the left battery row are connected to the bus bar 21. And are connected in series by an intermediate bus bar 21b. An end bus bar 21a and an end bus bar 21c are connected to the external terminal 1g at the positive end and the external terminal 1g at the negative end, respectively, of the plurality of battery cells 1 connected in series.

With such a configuration, each battery cell 1 accumulates the power supplied via the pair of external terminals 1g in the electrode group 1e in the battery can 1c sealed by the battery lid 1d, and stores the power in the electrode group 1e. The stored power can be supplied to the outside of the battery cell 1 via the pair of external terminals 1g. As shown in FIGS. 5 and 6, the plurality of oblong battery cells 1 constituting the battery module 20 are stacked in the thickness direction Dt with the plurality of cell holders 22 constituting the battery module 20 interposed therebetween. .

The cell holder 22 is configured to hold the battery cells 1 from both sides in the thickness direction Dt and stack a plurality of battery cells 1 in the thickness direction Dt. The cell holder 22 is made of, for example, an engineering plastic having electrical insulation such as polybutylene terephthalate (PBT), is interposed between the battery cells 1, and connects between the battery cells 1. It also functions as a separator to be insulated, or as a spacer for providing an interval between the battery cells 1.

As described above, the cell holder 22 extends in the thickness direction Dt toward the safety valve 1v along one end surface 1a along the thickness direction Dt of the battery cell 1 and is orthogonal to the thickness direction Dt along one end surface 1a. It has an extending portion 221 extending in the width direction Dw. As shown in FIG. 6, the extending portion 221 forms a concave void portion 222 between one end surface 1a of the battery cell 1 and an end surface 221a of the extending portion 221 opposite to the one end surface 1a.

For example, as shown in FIG. 4, the extending portion 221 is a widened portion in which the width in the thickness direction Dt is increased between a pair of external terminals 1 g arranged at both ends in the width direction Dw of the battery cell 1. have. Further, the extending portion 221 has, for example, a reduced width portion having a reduced width in the thickness direction Dt near the pair of external terminals 1g. The gap 222 is formed, for example, in a groove shape that extends from one end to the other end of the widened portion of the extending portion 221 extending along the width direction Dw of the battery cell 1 between the pair of external terminals 1g.

The gap 222 is formed, for example, between an inclined surface 221b provided at an end of the extension 221 adjacent to the safety valve 1v and one end 1a of the battery cell 1. The inclined surface 221b is inclined such that the closer to the safety valve 1v in the thickness direction Dt of the battery cell 1, the further away from the one end surface 1a of the battery cell 1. The inclination angle of the inclined surface 221b with respect to the one end surface 1a of the battery cell 1 is not particularly limited, but is, for example, 45 °.

The extension 221 may have, for example, ribs 221c shown in FIG. 6 at both ends of the widened portion in the width direction Dw of the battery cell 1. The rib 221c is provided, for example, at the distal end of the extending portion 221 that extends upward in the vertical direction toward the safety valve 1v. As a result, the cavity 222 is surrounded by the inclined surface 221 b of the extension 221, the pair of ribs 221 c, and the one end surface 1 a of the battery cell 1, and is formed in a concave shape having an opening upward.

The rib 221c is not provided, for example, at the distal end of the extending portion 221 that extends downward in the vertical direction toward the safety valve 1v. In other words, the leading end of the extending portion 221 extending downward in the vertical direction toward the safety valve 1v and forming the gap 222 does not contact the one end surface 1a of the battery cell 1. Further, the distance between the extending portion 221 and the one end surface 1a of the battery cell 1 is increased as the inclined surface 221b approaches the lower end in the vertical direction.

The cell holder 22 has, for example, a main body 223 facing a wide side surface which is a side surface having the largest area of the battery can 1c constituting the battery cell 1 in addition to the extending portion 221 forming the void portion 222. The main body 223 extends, for example, in the width direction Dw of the battery cell 1 and in the height direction Dh of the battery cell 1 perpendicular to the width direction Dw and the thickness direction Dt, and extends in the thickness direction Dt of the battery can 1c. Facing. The body portion 223 has a thickness in the thickness direction Dt of the battery cell 1 partially reduced at an end in the height direction Dh of the battery cell 1 connected to the extending portion 221, for example, so that the battery can 1c has a wider width. A gap is formed between the side surface.

As shown in FIG. 4, the pair of end plates 23 are plate-shaped members arranged on both sides in the stacking direction of the plurality of battery cells 1, and sandwich the plurality of battery cells 1 from both sides in the stacking direction. . The pair of end plates 23 are fixed to the pair of side blocks 24 and the center block 25 by fastening members such as bolts, for example, while applying a compressive force in the stacking direction of the plurality of battery cells 1.

The pair of side blocks 24 are block-shaped or plate-shaped members arranged so as to sandwich the two battery rows and the center block 25 from both sides in the width direction Dw of the battery cell 1. The center block 25 is a block-shaped or plate-shaped member arranged between two battery rows. The pair of side blocks 24 and the center block 25 have, for example, a protrusion projecting in the height direction Dh of the battery cell 1, and the protrusion is fixed to a fixing member (not shown) via a fastening member such as a bolt. By doing so, it is fixed to the housing 10.

As shown in FIGS. 3 and 4, the busbar case 26 is engaged with, for example, a protruding engagement portion provided on the cell holder 22, and covers a plurality of battery cells 1 so as to cover one end surfaces 1 a of the plurality of battery cells 1. The battery cell 1 is disposed so as to face one end surface 1a. The bus bar case 26 is a rectangular frame-shaped member made of engineering plastic such as PBT similar to the cell holder 22, for example, and has a plurality of openings for exposing the external terminals 1 g of the battery cell 1. Further, the bus bar case 26 has a protruding holding portion for holding the bus bar 21 in an opening for exposing the external terminal 1 g of the battery cell 1, and holds a plurality of bus bars 21 between the bus bars 21 adjacent to each other. Are insulated by partition walls.

FIG. 7 is a perspective view of the electrical component holder 30 housed in the housing of the battery pack shown in FIG. FIG. 8 is a perspective view of the electrical component holder 30 shown in FIG. 7 when viewed from the opposite direction. The electrical component holder 30 is a generally rectangular frame-shaped, plate-shaped or case-shaped member, and is made of, for example, an engineering plastic such as PBT, like the cell holder 22 and the busbar case 26. A pair of high voltage terminals 101 are provided at both ends of the electrical component holder 30 in the longitudinal direction.

(4) The electrical component holder 30 holds, for example, a control board 31, a relay 32, a fuse 33, a shunt resistor 34, and a pair of connection terminals 35. The control board 31 is fixed to the surface of the electrical component holder 30 facing the battery module 20 by a bolt, for example. The shunt resistor 34 is fixed to the control board 31 by, for example, a screw, and is arranged on a current path between the negative connection terminal 35 and the negative high voltage terminal 101.

The control board 31 is connected to each bus bar 21 connecting the battery cells 1 adjacent in the stacking direction via a voltage detection line, for example. The control board 31 includes, for example, a control circuit that measures and monitors the voltage of each battery cell 1 and controls and monitors the entire battery pack 100. The relay 32 and the fuse 33 are fixed to the electrical component holder 30 by, for example, screws, and are arranged in a current path between the positive connection terminal 35 and the positive high voltage terminal 101.

The positive connection terminal 35 disposed on the left side of the pair of connection terminals 35 shown in FIG. 8 is electrically connected to the right end bus bar 21a of the pair of

end bus bars

21a and 21c shown in FIG. And fixed by fastening members such as bolts. As described above, the right end bus bar 21a is the positive end bus bar 21a connected to the positive end of the plurality of battery cells 1 connected in series constituting the battery module 20.

The negative connection terminal 35 arranged on the right side of the pair of connection terminals 35 shown in FIG. 8 is electrically connected to the left end bus bar 21c of the pair of

end bus bars

21a and 21c shown in FIG. And fixed by fastening members such as bolts. As described above, the left end bus bar 21c is the negative end bus bar 21c connected to the negative end of the plurality of battery cells 1 connected in series constituting the battery module 20.

That is, in the battery pack 100 shown in FIGS. 1 and 2, the right high-voltage terminal 101 is a positive external terminal connected to the positive electrode side of the plurality of battery cells 1, and the left high-voltage terminal 101 is External terminal of the negative electrode connected to the negative electrode side of the battery cell 1 of FIG.

Hereinafter, the operation of the battery pack 100 according to the present embodiment will be described.

As described above, the battery pack 100 of the present embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, stores electric power supplied from electric equipment of the vehicle, and stores the stored electric power in electric equipment of the vehicle. To supply. The pair of high-voltage terminals 101 of the battery pack 100 are connected, for example, via a cable to a power supply device such as a vehicle generator or a device that consumes power such as a motor or an actuator.

When power is supplied to the pair of high-voltage terminals 101 from the power supply device, the battery pack 100 disconnects the pair of connection terminals 35, the end bus bar 21a, the bus bar 21, the intermediate bus bar 21b, and the end bus bar 21c. The plurality of battery cells 1 are charged through the battery. Further, the battery pack 100 supplies the electric power charged in the plurality of battery cells 1 via the bus bar 21, the intermediate bus bar 21b, the pair of

end bus bars

21a and 21c, the pair of connection terminals 35, the pair of high voltage terminals 101, and the like. And supply it to external equipment.

For example, when an abnormality occurs in one battery cell 1 of the battery pack 100 and the internal pressure of the battery cell 1 abnormally increases, the safety valve 1v of the battery cell 1 is opened to release the gas inside. As a result, the internal pressure of the battery cell 1 in which the abnormality has occurred is reduced to ensure safety. However, the electrolyte 1f inside the battery can 1c may leak from the safety valve 1v of the battery cell 1. In this case, the electrolyte 1f leaking from the safety valve 1v of the battery cell 1 disposed above flows downward, and the vertically adjacent battery cells 1 may be short-circuited by the electrolyte 1f.

On the other hand, as described above, the battery pack 100 according to the present embodiment holds the battery cells 1 in a flat rectangular shape and holds the battery cells 1 from both sides in the thickness direction Dt to form the battery cells 1 in the thickness direction. And a plurality of cell holders 22 stacked in the direction Dt. The battery cell 1 has a safety valve 1v on one end face 1a along the thickness direction Dt. The cell holder 22 has an extending portion 221 extending along the one end surface 1a of the battery cell 1 in the thickness direction Dt toward the safety valve 1v and extending along the one end surface 1a in a direction orthogonal to the thickness direction Dt. ing. Further, a concave void portion 222 is formed between one end surface 1a of the battery cell 1 and an end surface 221a of the extending portion 221 opposite to the one end surface 1a.

With this configuration, for example, even if the electrolyte 1f leaking from the safety valve 1v of the upper battery cell 1 shown in FIG. 6 flows downward along the one end surface 1a of the battery cell 1, the electrolyte 1f is not filled with the concave void. 222. Accordingly, it is possible to prevent a current path from being formed by the electrolyte 1f between the two vertically adjacent battery cells 1. Therefore, according to the battery pack 100 of the present embodiment, it is possible to prevent the upper and lower battery cells 1 from being short-circuited by the electrolyte 1f leaked when the safety valve 1v provided in the battery cell 1 is opened.

When the volume of the electrolyte 1 f leaked from the safety valve 1 v of the battery cell 1 is larger than the volume of the concave space 222, the electrolyte 1 f stored in the space 222 overflows and the one end face 1 a of the battery cell 1 Flows downward along the end face 221a of the extension 221 opposite to the above. However, also at the lower end of the extending portion 221 extending toward the safety valve 1v of the battery cell 1 below, between the one end surface 1a of the battery cell 1 and the end surface 221a of the extending portion 221 opposite to the one end surface 1a. , A concave void portion 222 is formed.

With this configuration, the electrolyte 1f overflowing from the gap 222 at the upper end of the extension 221 and flowing downward along the end surface 221a of the extension 221 drips from the lower end of the extension 221 to form a lower battery cell. 1 falls without contacting one end surface 1a. Accordingly, it is possible to prevent a current path from being formed by the electrolyte 1f between the two vertically adjacent battery cells 1. Therefore, according to the battery pack 100 of the present embodiment, it is possible to prevent the upper and lower battery cells 1 from being short-circuited by the electrolyte 1f leaked when the safety valve 1v provided in the battery cell 1 is opened.

In the battery pack 100 of the present embodiment, the battery cell 1 includes a flat rectangular battery can 1c, a battery lid 1d for closing an opening of the battery can 1c, an electrolyte 1f contained in the battery can 1c, and an electrode. It includes a group 1e and a pair of external terminals 1g connected to the electrode group 1e and attached to the battery lid 1d. The battery lid 1d is provided with a pair of external terminals 1g at both ends in the longitudinal direction of the outer surface that is the one end surface 1a of the battery cell 1, and a safety valve 1v is provided between the pair of external terminals 1g.

With this configuration, the external terminal 1g and the safety valve 1v can be easily arranged on the one end surface 1a along the thickness direction Dt of the battery cell 1. Further, a plurality of flat battery cells 1 can be stacked in the thickness direction Dt and connected in series or in parallel by the bus bar 21, the

end bus bars

21a and 21c, and the intermediate bus bar 21b. Further, in a state where the plurality of flat rectangular battery cells 1 are stacked in the thickness direction Dt, the safety valve 1v is exposed between the pair of external terminals 1g of each battery cell 1, and the safety valve 1v is arranged in the same direction. can do. Thereby, the extending part 221 is formed at one end of the cell holder 22 in the height direction Dh of the battery cell 1, and the concave void part 222 is formed between the one end face 1 a of the battery cell 1 and the end face 221 a of the extending part 221. Can be formed.

Further, in the battery pack 100 of the present embodiment, the void 222 is formed between the inclined surface 221 b provided at the end of the extension 221 adjacent to the safety valve 1 v and the one end 1 a of the battery cell 1. ing. The inclined surface 221b is inclined such that the closer to the safety valve 1v in the thickness direction Dt of the battery cell 1, the further away from the one end surface 1a of the battery cell 1.

With this configuration, a gap 222 having a required volume can be easily formed between the one end face 1a of the battery cell 1 and the end face 221a of the extension 221 opposite to the one end face 1a. Further, the distance between the lower end of the extending portion 221 and the one end surface 1a of the battery cell 1 can be further expanded. Thus, the electrolyte 1f that has flowed downward along the end surface 221a of the extending portion 221 can be less likely to be in contact with the one end surface 1a of the battery cell 1.

Further, in the battery pack 100 of the present embodiment, the extending portion 221 is formed between the pair of external terminals 1g arranged in the longitudinal direction of the one end surface 1a of the battery cell 1, that is, at both ends in the width direction Dw of the battery cell 1. The battery cell 1 has a widened portion in which the width in the thickness direction Dt is increased. The gap 222 is formed in a continuous groove shape from one end to the other end in the width direction Dw of the widened portion of the extending portion 221, and the extending portion 221 is formed at both ends of the widened portion in the width direction Dw of the battery cell 1. The portion has a rib 221c. The rib 221c is provided at a distal end of an extending portion 221 that extends vertically upward toward the safety valve 1v.

With this configuration, the movement of the battery cell 1 in the height direction Dh can be regulated by the extending portion 221 and the rib 221c. The cavity 222 is surrounded by the inclined surface 221b of the extension 221, the pair of ribs 221c, and the one end surface 1a of the battery cell 1, and is formed in a concave shape having an opening upward. This prevents the electrolyte 1f stored in the gap 222 from leaking from both ends of the gap 222 in the width direction Dw of the battery cell 1, and allows the electrolyte 222 to be stored more in the gap 222. it can.

Furthermore, in the battery pack 100 of the present embodiment, the rib 221c is not provided at the distal end of the extension 221 that extends downward in the vertical direction toward the safety valve 1v. In other words, the leading end of the extending portion 221 extending downward in the vertical direction toward the safety valve 1v and forming the gap 222 does not contact the one end surface 1a of the battery cell 1. Further, the distance between the extending portion 221 and the one end surface 1a of the battery cell 1 is increased as the inclined surface 221b approaches the lower end in the vertical direction.

With this configuration, it is possible to prevent the electrolytic solution 1f that has flowed downward along the end surface 221a of the extending portion 221 from flowing along the rib 221c to the one end surface 1a of the battery cell 1 below. Therefore, it is possible to make it difficult for the electrolytic solution 1f flowing down along the end face 221a of the extension portion 221 to be in contact with the one end face 1a of the battery cell 1 below.

The battery pack 100 of the present embodiment includes the housing 10 that houses the plurality of battery cells 1, and the plurality of battery cells 1 are stacked in a direction perpendicular to the bottom wall 10 b of the housing 10. With this configuration, it is possible to reduce the height dimension of the housing 10 in the direction perpendicular to the bottom wall 10b, as compared with the case where a plurality of oblate rectangular battery cells 1 are stacked in a direction parallel to the bottom wall 10b. become.

More specifically, when a plurality of oblong battery cells 1 are stacked in a direction parallel to the bottom wall 10b, the height dimension of the housing 10 is the dimension of the battery cell 1 in the height direction Dh and the busbar case. The lower limit is defined by the dimension of 26. On the other hand, by stacking the plurality of battery cells 1 in a direction perpendicular to the bottom wall 10b of the housing 10, it is possible to eliminate limitations due to the dimension of the battery cell 1 in the height direction Dh and the dimension of the bus bar case 26. Thus, the height dimension in the direction perpendicular to the bottom wall 10b of the housing 10 can be reduced.

As described above, according to the present embodiment, the battery pack 100 capable of preventing the upper and lower battery cells 1 from being short-circuited by the electrolyte 1f leaked when the safety valve 1v provided in the battery cell 1 is opened. Can be provided. Note that the battery pack of the present disclosure is not limited to the configuration of the battery pack 100 according to the above-described embodiment.

Hereinafter, a modified example of the battery pack 100 according to the above-described embodiment will be described with reference to FIGS. 9 and 10 with reference to FIGS. 1 to 5 and FIGS. 7 and 8. 9 and 10 are enlarged cross-sectional views showing a first modification and a second modification of the cell holder 22 shown in FIG. 6, respectively.

電池 A battery pack according to each of the modifications shown in FIGS. 9 and 10 is different from the battery pack 100 according to the above-described embodiment in the configuration of the extending portion 221 of the cell holder 22. Other configurations of the battery pack according to each modified example are the same as those of the battery pack 100 according to the above-described embodiment, and thus the same portions are denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 9, in the battery pack according to the first modification, the gap 222 includes a step 221 d in the thickness direction Dt provided at an end of the extension 221 adjacent to the safety valve 1 v, It is formed between one end face 1 a of the cell 1. According to this configuration, not only the same effect as in the void portion 222 shown in FIG. 6 can be obtained, but also the volume of the void portion 222 can be enlarged to store more electrolyte 1f. In addition, at the lower end of the extension 221, the electrolyte 1 f flowing downward along the end face 221 a of the extension 221 can be less likely to be in contact with the one end face 1 a of the battery cell 1 below.

In the battery pack according to the first modification shown in FIG. 9, a gap G is provided between one end surface 1a of the battery cell 1 and the extending portion 221 of the cell holder 22. This gap G is connected to the gap 222. With this configuration, it is possible to cause the electrolyte 1f contained in the void portion 222 to flow into the gap G and store more electrolyte 1f. Further, at the lower end of the extending portion 221, the electrolytic solution 1f flowing downward along the end surface 221a of the extending portion 221 can be less likely to be in contact with the one end surface 1a of the lower battery cell 1 by the gap G.

As shown in FIG. 10, in the battery pack according to the second modification, the void 222 is formed by a recess 221 e provided on an end surface of the extension 221 adjacent to the safety valve 1 v. With this configuration, according to the battery pack according to the present modification, not only the same effects as in the battery pack 100 according to the above-described embodiment can be obtained, but also the contact between the extending portion 221 and the one end surface 1a of the battery cell 1. By increasing the area, the movement of the battery cell 1 in the height direction Dh can be more reliably regulated.

As described above, the embodiment of the battery pack according to the present disclosure has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present disclosure. If any, they are included in the present disclosure.

DESCRIPTION OF SYMBOLS 1 Battery cell 1a One end face 1c Battery can 1d Battery lid 1e Electrode group 1f Electrolyte 1g External terminal 1v Safety valve 10 Housing 10b Bottom wall 22 Cell holder 100 Battery pack 221 Extension part 221a End face 221b Inclined face 221d Step part 221e Concave part 222 Void Part Dt Thickness direction G Gap

Claims

A battery pack comprising: a plurality of flat rectangular battery cells; and a plurality of cell holders that hold the battery cells from both sides in the thickness direction and stack the plurality of battery cells in the thickness direction.
The battery cell has a safety valve on one end surface along the thickness direction,
The cell holder has an extending portion extending in the thickness direction toward the safety valve along the one end surface of the battery cell and extending in a direction orthogonal to the thickness direction along the one end surface,
A battery pack, wherein a concave void portion is formed between the one end surface of the battery cell and an end surface of the extending portion opposite to the one end surface.
The battery cell has a flat rectangular battery can, a battery lid for closing an opening of the battery can, an electrolyte and an electrode group housed in the battery can, and the battery lid connected to the electrode group. And a pair of attached external terminals,
The battery lid, wherein the pair of external terminals are disposed at both ends in the longitudinal direction of the outer surface as the one end surface, and the safety valve is provided between the pair of external terminals. Item 7. The battery pack according to Item 1.
A gap is provided between the one end surface of the battery cell and the extending portion of the cell holder,
The battery pack according to claim 1, wherein the gap is connected to the gap.
The gap is formed between an inclined surface provided at an end of the extension portion adjacent to the safety valve and the one end surface of the battery cell,
2. The battery pack according to claim 1, wherein the inclined surface is inclined so as to move away from the one end surface as the battery cell approaches the safety valve in the thickness direction of the battery cell. 3.
The gap portion is formed between the step portion in the thickness direction provided at an end portion of the extension portion adjacent to the safety valve, and the one end surface of the battery cell. The battery pack according to claim 1.
2. The battery pack according to claim 1, wherein the gap is formed by a concave portion provided on an end surface of the extension portion adjacent to the safety valve. 3.
A housing housing the plurality of battery cells,
The battery pack according to claim 1, wherein the plurality of battery cells are stacked in a direction perpendicular to a bottom wall of the housing.