JP7023359B2 - Battery pack - Google Patents

Description

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

Conventionally, with respect to a battery pack in which a plurality of square batteries are connected in series and / or in parallel, an invention relating to a battery pack used for a battery-powered vehicle such as a hybrid vehicle (HEV) and an electric vehicle (PEV) is known (invention). See Patent Document 1 below). The main object of the invention described in Patent Document 1 is to provide a battery pack having improved insulation between adjacent square battery cells (see paragraph 0006 of the same document). As a means for achieving this object, Patent Document 1 discloses a battery pack having the following configuration.

The battery pack described in Patent Document 1 has a plurality of battery cells housed in a square outer can, and a plurality of batteries having insulating and heat insulating properties covering the outer periphery of the outer can, except for the electrode terminals of the battery cells. A separator and is provided. Each separator is interposed between the battery cells so that the outer can of the battery cell is in contact with both sides thereof, and the electrode terminals are exposed with the outer can of the battery cell covered with the separator, and this portion is connected. It is configured (see the same document, claim 1 and the like).

That is, in this conventional battery pack, a plurality of flat square battery cells are laminated in the thickness direction via a separator. Further, the square 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 for opening the valve when the internal pressure of the battery cell rises abnormally and releasing the gas inside the battery cell to the outside (see the same document, paragraph 0031 and FIG. 2).

Japanese Unexamined Patent Publication No. 2008-166191

In a battery pack, for example, due to space limitations, a plurality of battery cells may be stacked in the vertical direction. In this case, since the battery cells are arranged adjacent to each other on the upper and lower sides, when the safety valve provided on the battery cell arranged above is opened, the electrolytic solution leaked from the safety valve flows downward, and the electrolytic solution moves up and down. The battery cell may short-circuit.

The present disclosure provides a battery pack capable of preventing a short circuit between upper and lower battery cells due to an electrolytic solution leaked when a safety valve provided in the battery cell is opened.

One aspect of the present disclosure includes a plurality of flat square 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. In a battery pack, 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. It is a battery pack characterized in that a concave void portion is formed.

According to one aspect of the present disclosure, it is possible to provide a battery pack capable of preventing a short circuit between the upper and lower battery cells due to the electrolytic solution leaked when the safety valve provided in the battery cell is opened.

The external perspective view of the battery pack which concerns on embodiment of this disclosure. An exploded perspective view of the battery pack housing shown in FIG. 1 with the cover removed. FIG. 2 is a perspective view of a battery module housed in a battery pack housing shown in FIG. 2. FIG. 3 is a perspective view of a part of the battery module from which the bus bar case shown in FIG. 3 has been removed. FIG. 4 is a cross-sectional view of a part of the battery module along the VV line of FIG. FIG. 5 is an enlarged cross-sectional view of a part of the battery module shown in FIG. FIG. 2 is a perspective view of an electrical component holder housed in a battery pack housing shown in FIG. 2. A perspective view of the electrical component holder shown in FIG. 7 as viewed from the opposite direction. FIG. 5 is an enlarged cross-sectional view showing a modified example of the cell holder shown in FIG. FIG. 5 is an enlarged cross-sectional view showing a modified example of the cell holder shown in FIG.

Hereinafter, embodiments of the battery pack according to the present disclosure will be described with reference to the drawings. The directions such as up / down, front / back, and left / right in the following description are directions for explaining each part displayed in the drawing, and do not limit the direction when the battery pack is used.

FIG. 1 is an external perspective view of the battery pack 100 according to the 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 VV line shown in FIG. FIG. 6 is an enlarged cross-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 the battery cell 1 is cut without cutting the battery cell 1. 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 the electric equipment of the vehicle, and supplies the stored electric power to the electric equipment of the vehicle.

Although the details will be described later, the battery pack 100 of the present embodiment is mainly characterized by having the following configuration. The battery pack 100 includes a plurality of flat square 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. I have. The battery cell 1 has a safety valve 1v on one end surface 1a along the thickness direction Dt. The cell holder 22 has an extending portion 221 extending in the thickness direction Dt along one end surface 1a of the battery cell 1 toward the safety valve 1v and extending in a direction orthogonal to the thickness direction Dt along the one end surface 1a. ing. A concave gap portion 222 is formed between 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.

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 the dimensions in the front-rear depth direction are larger than the dimensions in the vertical height direction, and the dimensions in the left-right width direction are larger than the dimensions in the depth direction. ..

The housing 10 has, for example, a rectangular box-shaped main body portion 11 having an open upper portion and a lid-shaped cover 12 that closes an opening at the upper portion of the main body portion 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, recesses formed at the corners at both ends in the width direction at the front end in the depth direction, and openings are formed in the recesses. The battery pack 100 exposes a pair of high-voltage terminals 101, which are external terminals, from the housing 10 by an opening provided in the recess of the cover 12. The battery pack 100 is supplied with electric power from an external device via the high voltage terminal 101, and supplies electric power to the external device via the high voltage terminal 101.

Further, the cover 12 has, for example, a recess 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 this recess. The battery pack 100 exposes the signal connector 102 from the housing 10 by an opening provided in the recess of the cover 12. The battery pack 100 is connected to, for example, an electronic control unit mounted on a vehicle via a signal connector 102. The signal connector 102 is, for example, a connector for a control signal of the battery pack 100, and inputs / outputs information and receives electric power.

The battery module 20 is housed in the rear side of the inside of the housing 10 in the depth direction, and is fixed to the housing 10 by a fastening member such as a bolt. The battery module 20 includes a plurality of flat square 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. I have.

Further, the battery module 20 includes, for example, a bus bar 21 for connecting a plurality of battery cells 1, a pair of end plates 23 arranged 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. It is provided with a pair of side blocks 24 arranged at both left and right ends of the Dw. Further, the battery module 20 faces, for example, a center block 25 arranged between the battery cells 1 arranged on the left and right sides in the width direction Dw, and one end surface 1a along the thickness direction Dt of the plurality of battery cells 1. It is provided with a bus bar case 26 to be arranged.

As described above, the battery pack 100 of the present embodiment includes a housing 10 that accommodates a plurality of battery cells 1, and the plurality of battery cells 1 are stacked, for example, in a direction perpendicular to the bottom wall 10b of the housing 10. Will be done. The battery cell 1 is, for example, a square lithium ion secondary battery. As shown in FIGS. 4 and 5, the battery cell 1 has a generally rectangular parallelepiped flat shape. The battery cell 1 is connected to a flat square battery can 1c, a battery lid 1d that closes an opening of the battery can 1c, an electrode group 1e and an electrolytic solution 1f housed in the battery can 1c, and an electrode group 1e thereof. It is provided with a pair of external terminals 1g, which are attached to the battery lid 1d.

The battery lid 1d is, for example, a substantially rectangular plate-shaped member, and the battery can 1c is sealed by being joined to the opening of the battery can 1c by laser welding over the entire circumference. The battery can 1c and the battery lid 1d form a battery container that houses and seals the electrode group 1e and the electrolytic solution 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.

In the battery lid 1d, a pair of external terminals 1g are arranged at both ends in the longitudinal direction of the outer surface which 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 “width direction Dw”.

The safety valve 1v is provided on the battery lid 1d, for example, by thinning a part of the battery lid 1d to form a groove-shaped slit. The safety valve 1v is, for example, a gas discharge valve that cleaves 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 cleaving plate configured to cleave at a predetermined pressure to the 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 so as to face each other via a separator which is a long strip-shaped insulating member. The positive electrode constituting the electrode group 1e is connected to the external terminal 1g of the positive electrode, for example, via the current collector plate 1h of the positive electrode. The negative electrode constituting the electrode group 1e is connected to the external terminal 1g of the negative electrode, for example, via the current collector plate 1h of the negative electrode.

The electrolytic solution 1f is contained in the battery can 1c by being injected into the battery can 1c from, for example, a liquid injection port provided in the battery lid 1d, and is impregnated in the electrode group 1e. In the battery cell 1, after the electrolytic solution 1f is injected, for example, the battery can 1c is sealed by the battery lid 1d by joining the injection plug 1k to the injection port of the battery lid 1d by laser welding.

Of the pair of external terminals 1g of the battery cell 1, one is the external terminal 1g of the positive electrode connected to the positive electrode constituting the electrode group 1e, and the other is the negative electrode connected to the negative electrode constituting the electrode group 1e. The external terminal is 1 g. 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 the battery lid 1d, a gasket, and an insulating member and is connected to the current collector plate 1h.

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

The 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 done.

The bus bar 21 is, for example, a metal plate-shaped member having wire-leading properties such as aluminum or copper, which is bonded to the external terminal 1g of the battery cell 1 by laser welding or ultrasonic bonding, and is external to the adjacent battery cell 1. The terminals 1g are electrically connected.

In the battery pack 100 of the present embodiment, as shown in FIG. 4, the battery module 20 has two rows of battery rows composed of a plurality of flat square battery cells 1 stacked in the thickness direction Dt. The two rows of batteries in which the battery cells 1 are laminated in the thickness direction Dt are arranged on the left and right of the width direction Dw of the battery cells 1.

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

Further, in the battery cell 1 arranged at the bottom of the battery row on the left side shown in FIG. 4, the external terminal 1g of the positive electrode on the right side of the pair of external terminals 1g is connected to the intermediate bus bar 21b shown in FIG. There is. 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 of the negative electrode 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 cell 1 from the top to the bottom and the battery cell 1 from the bottom to the top of the left battery row constituting the right battery row are the bus bar 21. And are connected in series by an intermediate bus bar 21b. The end bus bar 21a and the end bus bar 21c are connected to the external terminal 1g at the end on the positive electrode side and the external terminal 1g at the end on the negative electrode side of the plurality of battery cells 1 connected in series, respectively.

With such a configuration, each battery cell 1 stores the electric power supplied through 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 electric power in the electrode group 1e. The stored electric 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 flat square battery cells 1 constituting the battery module 20 are laminated 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 an engineering plastic having electrical insulation such as polybutylene terephthalate (PBT), is interposed between the battery cell 1 and the battery cell 1, and is interposed between the battery cell 1 and the battery cell 1. It also functions as an insulating separator or a spacer that provides a space between the battery cell 1 and the battery cell 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 the 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 gap portion 222 between 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 thereof.

As shown in FIG. 4, the extending portion 221 is a widening portion having an expanded width in the thickness direction Dt between a pair of external terminals 1g arranged at both ends of the width direction Dw of the battery cell 1, for example. have. Further, the extending portion 221 has, for example, a reduced width portion whose width in the thickness direction Dt is reduced in the vicinity of the pair of external terminals 1g. The gap portion 222 is formed, for example, between a pair of external terminals 1g in a groove shape continuous from one end to the other end of the widening portion of the extending portion 221 extending along the width direction Dw of the battery cell 1.

The gap portion 222 is formed between, for example, an inclined surface 221b provided at an end portion of the extending portion 221 adjacent to the safety valve 1v and one end surface 1a of the battery cell 1. The inclined surface 221b is inclined so as to be closer to the safety valve 1v in the thickness direction Dt of the battery cell 1 so as to be farther from 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 °.

Further, the extending portion 221 may have ribs 221c shown in FIG. 6 at both ends of the widening portion in the width direction Dw of the battery cell 1, for example. The rib 221c is provided at the tip of the extending portion 221 extending upward in the vertical direction toward the safety valve 1v, for example. As a result, the gap portion 222 is surrounded by the inclined surface 221b of the extending portion 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.

Further, the rib 221c is not provided at the tip of the extending portion 221 extending downward in the vertical direction toward the safety valve 1v, for example. In other words, the tip portion forming the gap portion 222 of the extending portion 221 extending downward in the vertical direction toward the safety valve 1v is not in contact with the one end surface 1a of the battery cell 1. Further, the closer to the lower tip in the vertical direction by the inclined surface 221b, the wider the distance between the extending portion 221 and the one end surface 1a of the battery cell 1.

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

As shown in FIG. 4, the pair of end plates 23 are plate-shaped members arranged on both sides of the plurality of battery cells 1 in the stacking direction, 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 in a state where a compressive force is applied in the stacking direction of the plurality of battery cells 1, for example.

The pair of side blocks 24 are block-shaped or plate-shaped members arranged so as to sandwich the two rows of 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 rows of battery rows. The pair of side blocks 24 and the center block 25 have, for example, a convex portion protruding in the height direction Dh of the battery cell 1, and the convex portion 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 bus bar case 26 is engaged with, for example, a protrusion-shaped engaging portion provided on the cell holder 22 so as to cover one end surface 1a of the plurality of battery cells 1. It is arranged so as to face one end surface 1a of the battery cell 1. The bus bar case 26 is a rectangular frame-shaped member made of engineering plastic such as PBT similar to the cell holder 22, and has a plurality of openings for exposing the external terminal 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 the opening for exposing the external terminal 1 g of the battery cell 1, and is between the bus bars 21 adjacent to each other while holding the plurality of bus bars 21. Is insulated by a partition wall.

FIG. 7 is a perspective view of the electrical component holder 30 housed in the housing of the battery pack shown in FIG. 2. FIG. 8 is a perspective view of the electrical component holder 30 shown in FIG. 7 as viewed from the opposite direction. The electrical component holder 30 is a substantially rectangular frame-shaped, plate-shaped or case-shaped member, and is made of engineering plastic such as PBT, like the cell holder 22 and the bus bar case 26. A pair of high voltage terminals 101 are provided at both ends of the electrical component holder 30 in the longitudinal direction.

Further, 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, for example, the surface of the electrical component holder 30 facing the battery module 20 with bolts. The shunt resistor 34 is fixed to the control board 31 by a screw, for example, and is arranged in the current path between the connection terminal 35 of the negative electrode and the high voltage terminal 101 of the negative electrode.

The control board 31 is connected to, for example, each bus bar 21 connecting the battery cells 1 adjacent to each other in the stacking direction via a voltage detection line. 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, a screw, and are arranged in the current path between the connection terminal 35 of the positive electrode and the high voltage terminal 101 of the positive electrode.

Of the pair of connection terminals 35 shown in FIG. 8, the positive electrode connection terminal 35 arranged on the left side is electrically connected to the right end bus bar 21a of the pair of end bus bars 21a and 21c shown in FIG. It is fixed by a fastening member such as a bolt. As described above, the right end bus bar 21a is a positive electrode end bus bar 21a connected to the positive electrode side ends of a plurality of battery cells 1 connected in series constituting the battery module 20.

Further, among the pair of connection terminals 35 shown in FIG. 8, the negative electrode connection terminal 35 arranged on the right side is electrically connected to the left end bus bar 21c of the pair of end bus bars 21a and 21c shown in FIG. It is connected to and fixed by a fastening member such as a bolt. As described above, the left end bus bar 21c is a negative electrode end bus bar 21c connected to the negative electrode side ends of a 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 high voltage terminal 101 on the right side is an external terminal of the positive electrode connected to the positive electrode side of the plurality of battery cells 1, and the high voltage terminal 101 on the left side is a plurality. It is an external terminal of the negative electrode connected to the negative electrode side of the battery cell 1.

Hereinafter, the operation of the battery pack 100 of 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 the electric equipment of the vehicle, and uses the stored electric power as the electric equipment of the vehicle. Supply to. The pair of high-voltage terminals 101 of the battery pack 100 are connected to, for example, a device for supplying electric power such as a generator of a vehicle or a device that consumes electric power such as a motor or an actuator via a cable.

When power is supplied to the pair of high voltage terminals 101 from the power supply device, the battery pack 100 includes the pair of connection terminals 35, the end bus bar 21a, the bus bar 21, the intermediate bus bar 21b, the end bus bar 21c, and the like. A plurality of battery cells 1 are charged via the battery cell 1. Further, the battery pack 100 transfers 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 rises abnormally, the safety valve 1v of the battery cell 1 is cleaved to release the internal gas. As a result, the internal pressure of the battery cell 1 in which the abnormality has occurred decreases and safety is ensured, but the electrolytic solution 1f inside the battery can 1c may leak from the safety valve 1v of the battery cell 1. In this case, the electrolytic solution 1f leaked from the safety valve 1v of the battery cell 1 arranged above may flow downward, and the electrolytic solution 1f may short-circuit the vertically adjacent battery cells 1.

On the other hand, in the battery pack 100 of the present embodiment, as described above, the plurality of flat square battery cells 1 and the battery cells 1 are held from both sides in the thickness direction Dt to thicken the plurality of battery cells 1. It is provided with a plurality of cell holders 22 to be laminated in the longitudinal direction Dt. The battery cell 1 has a safety valve 1v on one end surface 1a along the thickness direction Dt. The cell holder 22 has an extending portion 221 extending in the thickness direction Dt along one end surface 1a of the battery cell 1 toward the safety valve 1v and extending in a direction orthogonal to the thickness direction Dt along the one end surface 1a. ing. A concave gap portion 222 is formed between 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.

With this configuration, for example, even if the electrolytic solution 1f leaked from the safety valve 1v of the upper battery cell 1 shown in FIG. 6 flows downward along one end surface 1a of the battery cell 1, the electrolytic solution 1f is a concave void portion. It is stored in 222. As a result, it is possible to prevent the current path from being formed by the electrolytic solution 1f between the two battery cells 1 adjacent to each other on the upper and lower sides. Therefore, according to the battery pack 100 of the present embodiment, it is possible to prevent a short circuit between the upper and lower battery cells 1 due to the electrolytic solution 1f leaked when the safety valve 1v provided in the battery cell 1 is opened.

Further, when the volume of the electrolytic solution 1f leaked from the safety valve 1v of the battery cell 1 is larger than the volume of the concave gap portion 222, the electrolytic solution 1f stored in the gap portion 222 overflows and one end surface 1a of the battery cell 1 is overflowed. It flows downward along the end face 221a of the extending portion 221 opposite to the above. However, even at the lower end of the extending portion 221 extending toward the safety valve 1v of the lower battery cell 1, between 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 electrolytic solution 1f that overflows from the gap portion 222 at the upper end of the extending portion 221 and flows downward along the end surface 221a of the extending portion 221 drips from the lower end of the extending portion 221 and is a lower battery cell. It falls without touching one end surface 1a of 1. As a result, it is possible to prevent the current path from being formed by the electrolytic solution 1f between the two battery cells 1 adjacent to each other on the upper and lower sides. Therefore, according to the battery pack 100 of the present embodiment, it is possible to prevent a short circuit between the upper and lower battery cells 1 due to the electrolytic solution 1f leaked when the safety valve 1v provided in the battery cell 1 is opened.

Further, in the battery pack 100 of the present embodiment, the battery cell 1 is a flat square battery can 1c, a battery lid 1d that closes an opening of the battery can 1c, an electrolytic solution 1f and an electrode housed in the battery can 1c. 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. In the battery lid 1d, a pair of external terminals 1g are arranged at both ends in the longitudinal direction of the outer surface which is 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 one end surface 1a along the thickness direction Dt of the battery cell 1. Further, a plurality of flat square 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, 21c and the intermediate bus bar 21b. Further, in a state where a plurality of flat square 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. As a result, the extending portion 221 is formed at one end of the cell holder 22 in the height direction Dh of the battery cell 1, and the concave gap portion 222 is formed between the one end surface 1a of the battery cell 1 and the end surface 221a of the extending portion 221. Can be formed.

Further, in the battery pack 100 of the present embodiment, the gap portion 222 is formed between the inclined surface 221b provided at the end portion of the extending portion 221 adjacent to the safety valve 1v and the one end surface 1a of the battery cell 1. ing. The inclined surface 221b is inclined so as to be closer to the safety valve 1v in the thickness direction Dt of the battery cell 1 so as to be farther from one end surface 1a of the battery cell 1.

With this configuration, a gap portion 222 having a required volume can be easily formed between 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. 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. As a result, the electrolytic solution 1f flowing downward along the end surface 221a of the extending portion 221 can be made difficult to come into 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 between a pair of external terminals 1g arranged at both ends of the one end surface 1a of the battery cell 1, that is, the width direction Dw of the battery cell 1. Therefore, it has a widened portion in which the width of the battery cell 1 in the thickness direction Dt is expanded. The gap portion 222 is formed in a groove shape continuous from one end to the other end in the width direction Dw of the widening portion of the extending portion 221, and the extending portion 221 is formed at both ends of the widening portion in the width direction Dw of the battery cell 1. The portion has a rib 221c. The rib 221c is provided at the tip of the extending portion 221 extending vertically upward toward the safety valve 1v.

With this configuration, the movement of the battery cell 1 in the height direction Dh can be restricted by the extending portion 221 and the rib 221c. Further, the gap portion 222 is surrounded by an inclined surface 221b of the extending portion 221, a pair of ribs 221c, and one end surface 1a of the battery cell 1, and is formed in a concave shape having an opening upward. As a result, the electrolytic solution 1f stored in the gap portion 222 can be prevented from leaking from both ends of the gap portion 222 in the width direction Dw of the battery cell 1, and more electrolytic solution 1f can be stored in the gap portion 222. can.

Further, in the battery pack 100 of the present embodiment, the rib 221c is not provided at the tip of the extending portion 221 extending downward in the vertical direction toward the safety valve 1v. In other words, the tip portion forming the gap portion 222 of the extending portion 221 extending downward in the vertical direction toward the safety valve 1v is not in contact with the one end surface 1a of the battery cell 1. Further, the closer to the lower tip in the vertical direction by the inclined surface 221b, the wider the distance between the extending portion 221 and the one end surface 1a of the battery cell 1.

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

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

More specifically, when a plurality of flat square battery cells 1 are laminated 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 bus bar case. The dimension of 26 defines the lower limit. On the other hand, by stacking the plurality of battery cells 1 in the direction perpendicular to the bottom wall 10b of the housing 10, it is possible to eliminate the limitation due to the dimensions of the battery cell 1 in the height direction Dh and the dimensions of the bus bar case 26. , It becomes possible to reduce the height dimension in the direction perpendicular to the bottom wall 10b of the housing 10.

As described above, according to the present embodiment, the battery pack 100 capable of preventing a short circuit between the upper and lower battery cells 1 due to the electrolytic solution 1f leaked when the safety valve 1v provided in the battery cell 1 is opened is provided. Can be provided. 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, modifications of the battery pack 100 according to the above-described embodiment will be described with reference to FIGS. 1 to 5 and FIGS. 7 and 8 with reference to FIGS. 9 and 10. 9 and 10 are enlarged cross-sectional views showing a first modified example and a second modified example of the cell holder 22 shown in FIG. 6, respectively.

In the battery pack according to each modification shown in FIGS. 9 and 10, the configuration of the extending portion 221 of the cell holder 22 is different from that of the battery pack 100 according to the above-described embodiment. Since the other configurations of the battery pack according to each modification are the same as those of the battery pack 100 according to the above-described embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 9, in the battery pack according to the first modification, the gap portion 222 includes a step portion 221d in the thickness direction Dt provided at an end adjacent to the safety valve 1v of the extending portion 221 and a battery. It is formed between the one end surface 1a of the cell 1 and the one end surface 1a. With this configuration, not only the same effect as that of the gap portion 222 shown in FIG. 6 can be obtained, but also the volume of the gap portion 222 can be expanded to store a larger amount of the electrolytic solution 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 made difficult to come into contact with the one end surface 1a of the lower battery cell 1.

Further, 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 portion 222. With this configuration, the electrolytic solution 1f contained in the gap portion 222 can flow into the gap G, and a larger amount of the electrolytic solution 1f can be stored. 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 made difficult to come into contact with the one end surface 1a of the lower battery cell 1 due to the gap G.

As shown in FIG. 10, in the battery pack according to the second modification, the gap portion 222 is formed by the recess 221e provided on the end surface adjacent to the safety valve 1v of the extending portion 221. With this configuration, according to the battery pack according to the present modification, not only the same effect as that of 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 can be obtained. The area can be expanded to more reliably regulate the movement of the battery cell 1 in the height direction Dh.

Although the embodiment of the battery pack according to the present disclosure has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are made without departing from the gist of the present disclosure. If any, they are included in this disclosure.

1 Battery cell 1a One end surface 1c Battery can 1d Battery lid 1e Electrode group 1f Electrolyte solution 1g External terminal 1v Safety valve 10 Housing 10b Bottom wall 22 Cell holder 100 Battery pack 221 Extended portion 221a End surface 221b Inclined surface 221d Stepped portion 221e Recessed portion 222 Part Dt Thickness direction G Gap

Claims (7)

A battery pack comprising a plurality of flat square 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.
Between the one end surface of the battery cell and the end surface of the extending portion opposite to the surface of the extending portion facing the one end surface, the end surface is closer to the one end surface of the battery cell than the end surface. A battery pack characterized in that a concave gap is formed at the position . The battery cell is connected to the battery lid having a flat square battery can, a battery lid that closes the opening of the battery can, an electrolytic solution and an electrode group contained in the battery can, and the electrode group. With a pair of attached external terminals,
The battery lid is characterized in that the pair of external terminals are arranged at both ends in the longitudinal direction of the outer surface, which is one end surface, and the safety valve is provided between the pair of external terminals. Item 1. 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 portion is formed between an inclined surface provided at an end portion of the extending portion adjacent to the safety valve and the one end surface of the battery cell.
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. The gap portion is characterized in that it is formed between the stepped portion in the thickness direction provided at the end portion of the extending portion adjacent to the safety valve and the one end surface of the battery cell. The battery pack according to claim 1. The battery pack according to claim 1, wherein the gap portion is formed by a recess provided on an end surface of the extending portion adjacent to the safety valve. A housing for accommodating the plurality of battery cells is provided.
The battery pack according to claim 1, wherein the plurality of battery cells are laminated in a direction perpendicular to the bottom wall of the housing.

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