JP2012230775A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery module which facilitates attaching of an exhaust duct and is capable of increasing the size of cleavage valves.SOLUTION: First and second battery cells 20A, 20B constituting a battery module are arrayed alternately and reversely. Both positive and negative electrode external terminals 21, 31 are provided on a battery lid 3 of each battery cell 20A, 20B, and a cleavage valve 12 is formed in the lid. A first battery cell 20A has the cleavage valve 12 formed closely to the negative electrode external terminal 31, and a second battery cell 20B has the cleavage valve 12 formed closely to the positive electrode external terminal 21. The cleavage valves 12 are arrayed linearly along the arrangement direction of battery cells 20A, 20B.

Description

  The present invention relates to a battery module, and more particularly, to a battery module including a plurality of battery cells having a cleavage valve that discharges gas generated inside the battery by overcharging / discharging or the like to the outside of the battery cell.

Secondary battery cells such as lithium ion secondary battery cells, nickel hydride secondary battery cells, and nickel cadmium secondary battery cells have been rapidly spreading in recent years as power sources for hybrid vehicles and electric vehicles.
A secondary battery cell used as a power source for an automobile is usually a battery module in which a plurality of secondary battery cells are connected in series with a bus bar.
In such secondary battery cells, when an abnormal state such as heat generation due to overcharge / discharge or internal short circuit occurs, gas is generated in the battery cell, the pressure in the battery container is increased, and the battery container may be damaged. There is.

For this reason, on one side of the battery container, a cleavage valve is provided that cleaves when the pressure of the gas generated in the battery container becomes high and releases the mist-like gas containing the electrolyte to the outside. ing.
And the discharge duct for discharging | emitting the mist-like gas discharge | released from the cleavage valve to the exterior from the space where battery modules, such as a motor vehicle, were installed in the battery module is provided, for example. The discharge duct is attached around the cleavage valve of each secondary battery cell so as to seal the upper part of the cleavage valve from the outside.

As a battery module equipped with a discharge duct, a structure is known in which a cleavage valve is provided at the center in the longitudinal direction of a battery lid provided with positive and negative external terminals, and an exhaust duct is arranged on the cleavage valve of each battery cell. (For example, refer to Patent Document 1).
Usually, the battery module has a structure in which adjacent secondary battery cells are arranged in opposite directions so that the positive external terminal and the negative external terminal face each other, and the positive and negative external terminals are connected in series by a bus bar. . Thus, if the cleavage valve of each secondary battery cell is arranged at the center of the battery lid in the longitudinal direction, the exhaust duct can be arranged in a straight line and can be easily mounted around each cleavage valve. It becomes.

JP 2010-108788 A

With the increase in voltage of the secondary battery cell, heat generation in an abnormal state increases, and the battery cell internal pressure due to the generated gas increases. To cope with this, it is necessary to enlarge the cleavage valve.
However, the secondary battery cell has a structure in which positive and negative current collector plates connected to a power generation element group having positive and negative electrode plates are connected to positive and negative external terminals. The attachment structure of the positive / negative current collector plates and the battery case requires a considerably wide area in the longitudinal direction of the battery case, which is the direction in which the positive / negative external terminals are arranged. In some cases, a liquid injection port for injecting the electrolyte into the secondary battery cell is provided between the positive and negative external terminals.
As in Patent Document 1, in the structure in which the cleavage valve is arranged at the center in the longitudinal direction of the battery container, the region where the cleavage valve is provided is narrow, and there is a restriction in increasing the size of the cleavage valve.

  In the battery module of the present invention, a power generation element group having positive and negative electrode plates, and positive and negative current collector plates connected to the positive and negative electrode plates are accommodated in the battery case, Electrolyte is injected, and positive and negative external terminals connected to the positive and negative current collector plates are arranged on one end side of one side of the battery container and the other end facing the one end side, A cleaving valve that cleaves and releases gas in the battery container when the internal pressure exceeds a predetermined value has a plurality of battery cells arranged on one side of the battery container between the positive and negative external terminals, and is adjacent In the battery module in which the battery cells are arranged with the positive and negative external terminals facing the opposite external terminals of the other party, one of the adjacent battery cells has a cleaving valve on the one side of the battery container. Located near the terminal side, adjacent battery cells Write is characterized in that the cleavage valve is disposed on the negative electrode external terminal side close in one side surface of the battery container.

  According to the battery module of the present invention, when the cleavage valve is attached, since there is no restriction to be positioned at the center on one side of the battery container, the cleavage valve can be freely arranged in the space area on one side of the battery container. It can be enlarged.

The external appearance perspective view as one Embodiment of the battery module of this invention. FIG. 2 is an external perspective view showing a state before a gas exhaust duct is attached in the battery module shown in FIG. 1. The external appearance perspective view which shows the state before connecting with a bus bar in the battery module illustrated in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV of the battery module illustrated in FIG. 1. FIG. 2 is an external perspective view of a first battery cell in the battery module illustrated in FIG. 1. FIG. 6 is an exploded perspective view of the first battery cell illustrated in FIG. 5. The external appearance perspective view of the 2nd battery cell in the battery module illustrated in FIG. FIG. 8 is an exploded perspective view of the second battery cell illustrated in FIG. 7. The expansion perspective view which shows the detail of an electric power generation element group. The external appearance perspective view as Embodiment 2 of the battery module of this invention. The external appearance perspective view of the battery cell which comprises the battery module illustrated by FIG. FIG. 11 is an enlarged cross-sectional view of the vicinity of the positive and negative external terminals of a pair of battery cells connected by a bus bar in the battery module illustrated in FIG. 10. The external appearance perspective view which shows the modification of a battery cell.

--Embodiment 1-
[Battery module overall configuration]
Hereinafter, an embodiment of a battery module of the present invention will be described with reference to the drawings.
The battery module of the present invention can be applied, for example, as a power storage device of an in-vehicle power supply device for an electric vehicle, particularly an electric vehicle. The electric vehicle includes a hybrid electric vehicle including an engine that is an internal combustion engine and an electric motor as a driving source of the vehicle, and a genuine electric vehicle using the electric motor as the only driving source of the vehicle.
FIG. 1 is an external perspective view as an embodiment of the battery module of the present invention, and FIG. 2 is an external perspective view showing a state before attaching a gas exhaust duct in the battery module shown in FIG. FIG. 3 is an external perspective view showing a state before the battery module shown in FIG. 2 is connected by a bus bar.

Each of the battery modules 10 illustrated in FIG. 1 includes a plurality of first battery cells 20A and a plurality of second battery cells 20B. The first and second battery cells 20A and 20B are exemplified as lithium ion battery cells.
The first battery cell 20A and the second battery cell 20B each have a positive external terminal 21 and a negative external terminal 31 exposed to the outside of the battery container.
All the first battery cells 20A and the second battery cells 20B constituting the battery module 10 are connected in series.
In FIG. 1, the battery module 10 is exemplified as a configuration in which each of the first battery cell 20A and the second battery cell 20B includes three battery cells, that is, a total of six battery cells. However, the battery module 10 can be configured by an arbitrary number of battery cells of six or more or less than six.

The first and second battery cells 20A and 20B are reversed such that adjacent battery cells are opposite to each other with the positive external terminal 21 and the negative external terminal 31 facing the opposite external terminals 21 and 31 of the opposite polarity. It is oriented, and is arranged in parallel and alternately in a direction orthogonal to the arrangement direction.
In the first and second battery cells 20A and 20B, the positive electrode external terminal 21 and the negative electrode external terminal 31 are respectively connected to the external terminals 21 and 31 having opposite polarities of adjacent battery cells, that is, the positive electrode external terminal 21 is The negative external terminal 31 and the negative external terminal 31 are connected to the positive external terminal 21 by the bus bar 11.
However, the positive external terminal 21 of the first battery cell 20A located at the foremost part (leftmost in FIG. 1) of the arrangement of the battery modules 10 and the second battery cell located at the rearmost (rightmost in FIG. 1). The negative external terminal 31 of 20B is not connected to the bus bar 11.

The first and second battery cells 20 </ b> A and 20 </ b> B each have a battery container including a battery can 2 having a bottom and an upper opening, and a battery lid 3 covering the opened top of the battery can 2. .
Between the positive electrode external terminal 21 and the negative electrode external terminal 31 in the battery lid 3 of each of the first and second battery cells 20A, 20B, a liquid injection for injecting the electrolyte into the battery container and the battery container. A portion 15 is formed.
The cleavage valve 12 of the first battery cell 20A is provided between the positive electrode external terminal 21 and the negative electrode external terminal 31 in the battery lid 3 at a position close to the negative electrode external terminal 31 side. The liquid injection part 15 of the first battery cell 20 </ b> A is provided between the cleavage valve 12 and the positive electrode external terminal 21 between the positive electrode external terminal 21 and the negative electrode external terminal 31 in the battery lid 3.
On the other hand, the cleavage valve 12 of the second battery cell 20B is provided between the positive electrode external terminal 21 and the negative electrode external terminal 31 in the battery lid 3 at a position close to the positive electrode external terminal 21 side. The liquid injection part 15 of the second battery cell 20 </ b> B is provided between the positive electrode external terminal 21 and the negative electrode external terminal 31 in the battery lid 3 and between the cleavage valve 12 and the negative electrode external terminal 21.

The distance from the center of the negative external terminal 31 of the first battery cell 20A to the center of the cleavage valve 12 and the distance from the center of the positive external terminal 21 of the second battery cell 20B to the center of the cleavage valve 12 are the same. . The distance from the center of the positive electrode external terminal 21 of the first battery cell 20A to the center of the liquid injection part 15 and the distance from the center of the negative electrode external terminal 31 of the second battery cell 20B to the center of the liquid injection part 15 are the same. It is.
Discharge ducts 40 are disposed on the cleavage valves 12 of the first and second battery cells 20A and 20B to discharge gas generated inside the first and second battery cells 20A and 20B. . The discharge duct 40 extends linearly along the arrangement of the cleavage valves 12. Further, as will be described in detail later, the discharge duct 40 has a plurality of connecting portions attached around the cleavage valve 12 in each battery lid 3 so as to seal the upper part of the cleavage valve 12 from the outside.

In the battery module 10 illustrated in FIG. 1, the positive external terminal 21 of the first battery cell 20 </ b> A located at the foremost part not connected to the bus bar 11 is the negative external terminal of the last battery cell of another battery module. Although not shown, it is connected to the high potential side of the inverter device. Also, in the battery module 10, is the negative external terminal 31 of the second battery cell 20 </ b> B located at the end not connected to the bus bar 11 connected to the positive external terminal of the battery cell in the front row of another battery module? Or, although not shown, it is connected to the low potential side of the inverter device.
In this way, a plurality of battery modules 10 are connected in series to form a battery module device, which is connected to an inverter device (not shown).

  The inverter device converts DC power from the battery module device into three-phase AC power, and, for example, drives a motor generator in a vehicle drive system. Further, in a state where the motor generator is driven as a generator, regenerative power is supplied to the inverter device to charge each of the battery cells 20A and 20B.

Although not shown, each bus bar 11 of the battery module 10 is connected to an IC including a differential amplifier and a microcomputer functioning as a host controller of the IC through a multiplexer through a connection conductor for voltage detection. The first and second battery cells 20A and 20B to be connected are sequentially switched by the multiplexer, and the voltages of the first and second battery cells 20A and 20B are detected by the differential amplifier. The detected voltages of the first and second battery cells 20A and 20B are converted into digital values by the A / D conversion circuit and held in the storage unit of the microcomputer. When it is detected that each of the first and second battery cells 20A and 20B is overcharged, the first and second battery cells 20A and 20B are disposed between the positive electrode terminal and the negative electrode terminal of each of the first and second battery cells 20A and 20B. A balancing switch (not shown) is turned on to discharge each battery cell 20A, 20B.
A cell controller composed of a microcomputer and a plurality of ICs controls the measurement of the voltage, total voltage, and current of each of the first and second battery cells 20A, 20B, and also controls charge / discharge.
Although not shown, the microcomputer rotates the number of rotations of a cooling fan that cools the battery module 10 based on the input temperature of the first and second battery cells 20A and 20B or the average temperature of the battery module 10. Alternatively, the driver that adjusts the cooling water supply amount and the pump speed are controlled.

[First battery cell]
5 is an external perspective view of the first battery cell in the battery module illustrated in FIG. 1, and FIG. 6 is an exploded perspective view of the first battery cell illustrated in FIG.
20 A of 1st battery cells have a battery container comprised by the battery can 2 which consists of iron or an aluminum-type metal, and the battery cover 3 which consists of an aluminum-type metal.
The battery can 2 has a flat rectangular tube shape having a bottom and an opening 2a at the top. The battery lid 3 covers the opening 2a of the battery can 2 and the peripheral edge thereof is joined to the battery can 2 by laser welding, for example.

  An insulating bag 7 made of an insulating material is accommodated inside the battery can 2, and a power generation element group 6 in which a positive electrode plate and a negative electrode plate are wound through a separator is accommodated in the insulating bag 7.

FIG. 9 is an enlarged perspective view of the power generation element group 6.
As shown in FIG. 9, the power generating element group 6 includes a flat wound that is obtained by flattening a wound electrode group that is wound around a plurality of times by overlapping a separator 6C, a negative electrode plate 6D, a separator 6C, and a positive electrode plate 6E in this order. It has a structure. The wound electrode group is reduced in weight by omitting the shaft core, and as a substitute for the shaft core, a separator 6C is wound around the winding start end portion (the power generation element group central portion) several times. In addition, the separator 6C is wound several times around the winding end end portion (power generation element group surface layer portion) to ensure insulation, and in addition, one side of the winding end end of the separator 6C is to prevent unwinding. It is stopped by a tape (not shown) coated with an adhesive.

  In the positive electrode plate 6E, a positive electrode active material mixture containing, for example, a lithium-containing transition metal double oxide such as lithium manganate as a positive electrode active material on both surfaces of an aluminum alloy foil (positive electrode current collector foil) is substantially uniform and substantially uniform. It is made by coating. On both sides of the aluminum alloy foil, the positive electrode active material mixture is not coated on one side along the longitudinal direction, and a positive electrode uncoated portion 6A in which the aluminum alloy foil is exposed is formed.

  In the negative electrode plate 6D, a negative electrode active material mixture containing a carbon material such as graphite capable of occluding and releasing lithium ions as a negative electrode active material on both surfaces of a copper alloy foil (negative electrode current collector foil) is substantially uniform and substantially uniform. It is made by painting. On both sides of the copper alloy foil, a negative electrode active material mixture is not coated on one side along the longitudinal direction, and a negative electrode uncoated portion 6B in which the copper alloy foil is exposed is formed. The positive electrode uncoated portion 6 </ b> A and the negative electrode uncoated portion 6 </ b> B are provided at opposite peripheral edge portions of the power generation element group 6.

  The length of the negative electrode plate 6D in the winding direction is such that when the positive electrode plate 6E and the negative electrode plate 6D are wound, the positive electrode plate 6E protrudes from the negative electrode plate 6D in the winding direction at the innermost winding and the outermost winding. In order to prevent this, it is set longer than the length of the positive electrode plate 6E. In addition, the length in the direction orthogonal to the winding direction of the negative electrode active material mixture applied to the negative electrode plate 6D, in other words, the length in the width direction is the positive electrode active material mixture applied to the positive electrode plate 6E. It is formed larger than the width of the agent. Therefore, also in the width direction, the positive electrode active material mixture applied to the positive electrode plate 6E does not protrude beyond the negative electrode active material mixture applied to the negative electrode plate 6D. If there is a portion of the negative electrode current collector foil that does not face the positive electrode active material, lithium contained in the positive electrode active material is ionized, penetrates the separator, and deposits on that portion. Thereby, an internal short circuit may occur. Thus, it can prevent by making a negative electrode active material area | region wider than a positive electrode active material area | region.

  The separator 6C is made of a microporous sheet material through which lithium ions can pass. In this example, a polyethylene sheet having a thickness of several tens of μm is used.

As described above, the power generation element group 6 has a flat wound structure in which the separator 6C, the negative electrode plate 6D, the separator 6C, and the positive electrode plate 6E are stacked in this order, wound around a plurality of times, and flattened.
In the power generation element group 6 having the flat wound structure, as illustrated in FIG. 6, the positive electrode uncoated portion 6 </ b> A and the negative electrode uncoated portion 6 </ b> B have shafts on one end side and the other end side in the width direction, respectively. It is wound around the core to form a multilayer structure in which the wound portions are polymerized with each other.

The positive electrode current collector plate 22 is joined to the positive electrode uncoated portion 6A by ultrasonic welding.
The positive electrode current collector plate 22 is formed of, for example, an aluminum-based metal, and includes a mounting portion 23 that is parallel to the battery lid 3 and a current collecting portion 24 that extends in a direction perpendicular to the mounting portion 23. A bent portion 25 bent inward is formed in the current collector 24, and the bent portion 25 is joined to the positive electrode uncoated portion 6A. A through hole 23 a is formed in the attachment portion 23.

The joining of the positive electrode current collector plate 22 and the positive electrode uncoated portion 6A is performed as follows, for example.
The lower surface of the multilayer structure portion formed by the positive electrode uncoated portion 6A wound around the shaft core is supported by the anvil. Further, the bent portion 25 of the positive electrode current collector plate 22 is brought into close contact with the upper surface of the multilayer structure portion formed by the positive electrode uncoated portion 6A and pressed against the anvil (not shown) side. In this state, the positive electrode uncoated portion 6A wound around the shaft core to form a multilayer structure is sandwiched between the bent portion 25 of the positive electrode current collector plate 22 and the anvil and is in close contact with each other. Then, ultrasonic welding is performed by contacting a horn with the upper surface of the bent portion 25 of the positive electrode current collector plate 22. Thereby, while the superposition | polymerization part of 6A of positive electrode uncoated parts is mutually joined, 6A of positive electrode uncoated parts and the bending part 25 of the positive electrode current collecting plate 22 are joined.

The negative electrode current collector plate 32 is made of a copper-based metal, but has a mounting portion 33, a current collector portion 34, and a bent portion 35, and has the same shape and size as the positive electrode current collector plate 22.
The negative electrode current collector plate 32 and the negative electrode uncoated portion 6B can be joined in the same manner as the positive electrode current collector plate 22 and the positive electrode uncoated portion 6A. The overlapping portions of the portion 6B are joined together, and the negative electrode uncoated portion 6B and the bent portion 35 of the negative electrode current collector plate 32 are joined.

The battery lid 3 is formed with through holes 3 a and 3 b for attaching the positive external terminal 21 and the negative external terminal 31.
In addition, a cleavage valve 12 and a liquid inlet 13 are formed in the battery lid 3. The liquid injection port 13 is a through hole for injecting an electrolytic solution. The liquid injection port 13 is sealed by fitting the liquid injection plug 14 and laser welding after injecting the electrolytic solution. A liquid injection part 15 is constituted by the liquid injection port 13 and the liquid injection stopper 14.

  The cleavage valve 12 has a function of discharging gas generated from the inside when an abnormality such as heat generation due to overcharge / discharge or internal short circuit occurs and the pressure in the first battery cell 20A becomes high. The cleavage valve 12 has a structure in which a groove having a V-shaped or U-shaped cross section is formed in a part of the battery lid 3 by pressing, and the remaining portion is thin. The thinned portion formed by forming a groove having a V-shaped or U-shaped cross section is cleaved by the pressure of the gas generated in the battery container, and the mist-like gas containing the electrolytic solution is released to the outside. .

The cleavage valve 12 is formed closer to the through hole 3b side of the battery lid 3 to which the negative electrode external terminal 31 is attached. The shape of the cleavage valve 12 is such that the size in the longitudinal direction connecting the positive electrode external terminal 21 and the negative electrode external terminal 31 is long. It is formed in an elongated shape larger than the size in the short direction perpendicular to the direction, in other words, the width direction. Therefore, it can be formed in a larger shape than the circular shape whose size is limited by the width of the battery lid 3.
The center of the cleavage valve 12 is disposed closer to the negative electrode external terminal 31 side than the center of the battery lid 3 in the longitudinal direction. In this case, the entire cleavage valve 12 may be located closer to the negative electrode external terminal 31 side than the center in the longitudinal direction of the battery lid 3, but a part of the cleavage valve 12 is the center in the longitudinal direction of the battery lid 3. It may be located closer to the positive electrode external terminal 21 side.

  Reference numeral 26 denotes an insulating ring having a lower cylindrical portion inserted into the through hole 3 a of the battery lid 3 and an upper cylindrical portion placed on the peripheral edge of the through hole 3 a of the battery lid 3. The insulating ring 26 has a through hole 26 a through which the positive external terminal 21 is inserted. Reference numeral 27 denotes a gasket having a through-hole 27a through which the lower cylindrical portion of the insulating ring 26 is inserted.

  In order to attach the positive electrode current collector plate 22 to the battery lid 3, first, the lower cylindrical portion of the insulating ring 26 is fitted into the through hole 3 a of the battery lid 3 and the through hole 27 a of the gasket 27. Next, the positive external terminal 21 is inserted into the through hole 26 a of the insulating ring 26. In this state, the lower end portion of the positive electrode external terminal 21 protrudes downward from the lower surface of the flat portion 27b in which the through hole 27a of the gasket 27 is formed. Next, the through hole 23 a of the attachment portion 23 of the positive electrode current collector plate 22 is inserted into the lower end portion of the lower cylindrical portion of the positive electrode external terminal 21. Then, the upper and lower surfaces of the positive electrode external terminal 21 are pressed to caulk the positive electrode current collector plate 22 and the positive electrode external terminal 21.

In this state, the positive external terminal 21 is insulated from the battery lid 3 by the insulating ring 26 and the gasket 27. The positive electrode current collector plate 22 is insulated from the battery lid 3 by a gasket 27.
Thereafter, as described above, the bent portion 25 of the positive electrode current collector plate 22 is joined to the positive electrode uncoated portion 6A of the power generation element group 6 by ultrasonic welding. Thereby, the positive electrode external terminal 21 is connected to the positive electrode plate 6E.

The method of attaching the negative electrode current collector plate 32 to the battery lid 3 is the same as that of the positive electrode current collector plate 22.
In a state where the negative electrode current collector plate 32 and the negative electrode external terminal 31 are attached to the battery cover 3 by caulking, the negative electrode external terminal 31 is insulated from the battery cover 3 by the insulating ring 26 and the gasket 27. Further, the negative electrode current collector plate 32 is insulated from the battery lid 3 by the gasket 27.
Further, the negative electrode external terminal 31 is connected to the negative electrode plate 6D by joining the bent portion 35 of the negative electrode current collector plate 32 to the negative electrode uncoated portion 6B of the power generation element group 6 by ultrasonic welding.

The power generation element assembly in which the power generation element group 6, the positive / negative current collector plates 22 and 32, and the battery lid 3 are integrated is housed in an insulating bag 7. In a state where the power generation element assembly is accommodated in the insulating bag 7, a gap is formed between the lower surface of the battery lid 3 of the power generation element assembly and the upper end of the insulating bag 7. The insulating bag 7 in which the power generation element assembly is accommodated is accommodated in the battery can 2. In this state, the power generation element assembly and the battery can 2 are insulated.
Next, the peripheral edge of the battery lid 3 is joined to the upper edge of the battery can 2 by laser welding or the like. Then, a nonaqueous electrolytic solution is injected from a liquid injection port 13 formed in the battery lid 3. As an example of the non-aqueous electrolyte, a solution in which a lithium salt is dissolved in a carbonate solvent can be used.
After injecting the nonaqueous electrolytic solution, the injection port 13 is sealed with the injection plug 14 to form the first battery cell 20A shown in FIG.

[Second battery cell]
7 is an external perspective view of the second battery cell in the battery module illustrated in FIG. 1, and FIG. 8 is an exploded perspective view of the second battery cell illustrated in FIG.
When the second battery cell 20B shown in FIG. 7 is compared with the first battery cell 20A shown in FIG. 5, the cleavage valve 12 formed on the battery lid 3 with respect to the positive and negative external terminals 21 and 31 is shown. Only the position is different.
That is, in the first battery cell 20 </ b> A, the cleavage valve 12 is located closer to the negative electrode external terminal 31 side than the positive electrode external terminal 21 side in the longitudinal direction of the battery lid 3.
On the other hand, in the second battery cell 20B, the cleavage valve 12 is located closer to the positive external terminal 21 side than the negative external terminal 31 side in the longitudinal direction of the battery lid 3.

When the internal structure of the second battery cell 20B shown in FIG. 8 is compared with the internal structure of the first battery cell 20A shown in FIG. 6, all the others are the same except that the left and right sides of the battery cover 3 are reversed. Are the same.
That is, also in the second battery cell 20B, the positive electrode current collector plate 22 is welded to the positive electrode uncoated portion 6A of the power generation element group 6, and the positive electrode current collector plate 22 and the positive electrode external terminal 21 are caulked to the battery lid 3. It is attached. Further, the negative electrode current collector plate 32 is welded to the negative electrode uncoated portion 6 </ b> B of the power generation element group 6, and the negative electrode current collector plate 32 and the negative electrode external terminal 31 are caulked and attached to the battery lid 3.

  However, in the second battery cell 20 </ b> B, the positive external terminal 21 is inserted into the through hole 3 b of the battery lid 3, and the negative external terminal 31 is inserted into the through hole 3 a of the battery cover 3 and attached to the battery cover 3. . In this structure, the positive battery external terminal 21 is inserted into the through hole 3 a of the battery cover 3, and the negative battery external terminal 31 is inserted into the through hole 3 b of the battery cover 3 and attached to the battery cover 3. The reverse is the through-hole to which it is attached.

That is, the second battery cell 20B has the power generation element group 6 assembled to the first battery cell 20A and the positive and negative current collectors in a state where the left and right sides of the battery lid 3 used in the first battery cell 20A are reversed. The plates 22 and 32 and the positive and negative external terminals 21 and 31 are assembled to the battery lid 3.
As described above, all the constituent members of the first battery cell 20A are the same as those of the second battery cell 20B.

A plurality of the first battery cell 20A and the second battery cell 20B are arranged in parallel so that the positive and negative external terminals 21 and 31 are opposed to each other so that the opposite external terminals of opposite polarity are opposed to each other. The arranged state is illustrated in FIG.
In this state, the line connecting the centers of the cleavage valves 12 formed on the battery lids 3 of the first and second battery cells 20A, 20B is linear at a position shifted from the longitudinal center of the battery lid 3. .

2 shows that the positive external terminal 21 and the negative external terminal 31 of the first and second battery cells 20A and 20B are connected to the external terminals of opposite polarities of adjacent battery cells, that is, the positive external terminal 21 is connected to the negative external terminal 31. The negative external terminal 31 is connected to the positive external terminal 21 by the bus bar 11.
The positive / negative external terminals 21 and 31 and the bus bar 11 are joined by arc welding such as TIG (Titan Inert Gas) welding.

  In the state where the first battery cell 20A and the second battery cell 20B are arranged so that the cleavage valves 12 are linear, the mist-like shape discharged from the first and second battery cells 20A, 20B A discharge duct 40 for discharging gas is attached to each battery lid 3 of the first and second battery cells 20A, 20B.

[Exhaust duct mounting structure]
FIG. 4 is an enlarged cross-sectional view taken along line IV-IV of the battery module shown in FIG. 1 and shows a mounting structure for the discharge duct and the battery lid.
Although not shown in FIGS. 2 and 3, a plurality of protrusions 37 are erected around the cleavage valve 12 of the battery lid 3 so as to be parallel to each other and toward the outside of the container. The protrusion 37 is formed in a cylindrical shape by pressing a predetermined position of the flat battery lid 3.

  As shown in FIG. 1, the discharge duct 40 is fixed to the battery lid 3 and collects and guides the gas discharged from the cleavage valve 12. The discharge duct 40 is made of an elastically deformable resin (such as polyphenylene sulfide resin).

The discharge duct 40 has a structure in which a plurality of connecting portions 41 corresponding to the respective cleavage valves 12 and a conduit portion 45 that connects these connecting portions 41 are integrally formed. The cross-sectional shape of the conduit part 45 is elliptical in order to suppress the dimension of the battery module 10 in the height direction and increase the gas discharge capacity.
The plurality of connecting portions 41 and the conduit portion 45 communicate with each other to form a gas passage. Each connecting portion 41 has a flat plate-like base portion 42 in which a circular opening is formed, and a cylindrical portion 43 erected on the base portion 42.

The base 42 is arranged in contact with the upper surface of the battery lid 3 on the outer periphery of the cleavage valve 12.
In the portions where the base 42 and the battery lid 3 are in contact with each other, a groove having an elliptical shape in plan view is formed in each member, and an annular gasket (O-ring) 36 is disposed between the grooves. ing.

The base portion 42 is provided with a through-hole through which the protrusion 37 provided on the battery lid 3 is inserted.
The discharge duct 40 is fixed to the battery lid 3 by caulking the protrusion 37 in a state where the protrusion 37 is inserted through the through-hole. It is preferable to form the projection 37 at a position outside the conduit portion 45 in plan view so that caulking can be easily performed.

  In the battery module 10 according to the embodiment configured as described above, since the cleavage valves 12 of the first and second battery cells 20A and 20B are linearly arranged, the conduit portion 45 of the discharge duct 40 is provided. It can be straight. For this reason, attachment of the connecting portion 41 of the discharge duct 40 and each battery lid 3 is facilitated.

  In the above-described embodiment, the cleavage valves 12 of the first and second battery cells 20A and 20B are shifted from the center in the longitudinal direction of the battery cover 3 toward one side of the positive and negative external terminals 21 and 31, respectively. Formed at different positions. If the liquid injection part 15 is arranged close to one of the positive and negative external terminals 21 and 31 of the battery lid 3, a wide space is generated between the liquid injection part 15 and the other external terminal. For this reason, by forming the cleavage valve 12 in this wide space region, the size can be increased, and a large amount of gas can be instantaneously discharged from the cleavage valve 12.

  In the above embodiment, the shape of the cleavage valve 12 is an elongated oval shape whose size in the longitudinal direction is larger than the size in the width direction of the battery lid 3. For this reason, it can be set as a size larger than the circular cleavage valve whose width | variety of the battery cover 3 becomes an upper limit.

--Embodiment 2-
FIG. 10 is an external perspective view of the battery module according to the second embodiment of the present invention, and FIG. 11 is an external perspective view of battery cells constituting the battery module shown in FIG.
The battery module 50 according to the second embodiment includes a plurality of first and second battery cells 60A and 60B.
Each of the first and second battery cells 60 </ b> A and 60 </ b> B includes a positive external terminal 61 and a negative external terminal 62. Similar to the case of the first embodiment, also in the case of the second embodiment, the first battery cell 60A and the second battery cell 60B are different in that the battery lid 3 is reversed and assembled to the power generation element assembly. The components are the same.

As shown in FIG. 11, the positive external terminal 61 and the negative external terminal 62 in each of the first and second battery cells 60A and 60B have a large-diameter base 63 and a small-diameter formed with a male screw. It has a bolt-like structure having a mounting portion 64.
A bus bar 11 for connecting the positive and negative external terminals 61 and 62 facing each other between the adjacent first and second battery cells 60A and 60B is a nut 71 engaged with the male screw of the positive and negative external terminals 61 and 62. It is fixed by.

12 is an enlarged cross-sectional view showing the vicinity of the positive and negative external terminals of a pair of battery cells connected by a bus bar in the battery module shown in FIG.
The battery lid 3 of the first and second battery cells 60A, 60B is formed with a through hole into which an insulating member 74 having an opening at the center is fitted. An electrode connection plate 65 is fitted in a through hole formed in the insulating member 74.

A positive electrode current collector plate 66 is fixed to the battery lid 3 by caulking or the like on one electrode connection plate 65a. The electrode connection plate 65a and the positive electrode current collector plate 66 are made of an aluminum-based metal.
On the other electrode connection plate 65b, a negative electrode current collector plate 67 is fixed to the battery lid 3 by caulking or the like. The electrode connection plate 65b and the negative electrode current collector plate 67 are formed of a copper-based metal.
The positive electrode current collector plate 66 and the negative electrode current collector plate 67 are bent in a substantially vertical direction from an attachment portion attached to the battery lid 3, and further inclined toward the central portion side in the thickness direction of the battery cell. On the part side, it again has a shape bent in a direction perpendicular to the mounting part. In this central portion, the positive electrode current collector plate 66 is joined to the positive electrode mixture untreated portion, and the negative electrode current collector plate 67 is joined to the negative electrode mixture untreated portion by ultrasonic welding.

The positive and negative current collecting plates 66 and 67 and the electrode connecting plates 65a and 65b are insulated from the battery lid 3 by an insulating member 74.
A positive external terminal 61 or a negative external terminal 62 is connected on each electrode connection plate 65a, 65b. This connection can be performed by caulking the positive electrode external terminal 61 or the negative electrode external terminal 62 and each electrode connection plate 65 directly or via a conductive connection plate (not shown).

  The adjacent positive external terminal 61 and negative external terminal 62 are connected by the bus bar 11. The bus bar 11 is formed with a through hole through which the mounting portion 64 of the positive external terminal 61 and the negative external terminal 62 is inserted. The bus bar 11 is attached to the attachment portions 64 of the positive and negative external terminals 61 and 62 by inserting the through holes, and the nut 71 is fastened to the screw of each attachment portion 64 to fix the bus bar 11. In this state, the positive external terminal 61 and the negative external terminal 62 are electrically connected by the bus bar 61.

  Also in the battery module 50 of the second embodiment, the center of the cleavage valve 12 of the first and second battery cells 60A, 60B is on one side of the positive and negative external terminals 61, 62 from the center in the longitudinal direction of the battery lid 3. It is arranged in a straight line at a position shifted to the side. Therefore, the same effects as those of the first embodiment are obtained.

[Modification]
In the first and second embodiments, the battery containers of the first and second battery cells 20A, 20B or 60A, 60B are constituted by the battery can 2 and the battery lid 3 formed separately from the battery can 2. The positive and negative external terminals 21, 31 or 61, 62 were configured to be attached to the battery lid 3.
FIG. 13 is an external perspective view showing a modified example of the battery cell.
Also in the battery cell shown in FIG. 13, the first battery cell and the second battery cell are all the same, except that the left and right sides of the battery lid 3 are opposite.
Therefore, the battery cell 80 will be described as a representative of the first and second battery cells.

  The battery cell 80 has a battery container constituted by a battery can 83 and a battery lid 84 formed separately from the battery can 83. The battery can 83 has an upper portion 81 and a side wall portion 82 having a U-shaped cross section formed integrally with the upper portion 81. One of the pair of large-area side surfaces in the side wall portion 82 is opened, and the battery lid 84 is attached by closing the opening of the battery can 83. The battery can 83 and the battery lid 84 can be attached by laser welding or the like.

The upper portion 81 of the battery can 83 corresponds to the battery lid 3 of the first embodiment.
That is, the cleavage valve 12 is formed in the upper part 81 and the liquid injection part 15 is provided. Also, positive and negative external terminals 21 and 31 are attached.
A battery module can be configured using the battery cell 80 shown in the third embodiment. The battery cell 80 of the third embodiment shown in FIG. 13 is illustrated as having the positive / negative external terminals 21 and 31 shown in the first embodiment, but the positive / negative external terminals 61 shown in the second embodiment, A structure having 62 may also be used.

In each of the above embodiments, the cleavage valve 12 is disposed closer to the negative electrode external terminals 31 and 62 side of the first battery cells 20A and 60A, and the positive battery external terminals 21 and 61 side of the second battery cells 20B and 60B. It was illustrated as a structure arranged closer.
However, contrary to the above structure, the cleavage valve 12 is disposed closer to the positive external terminals 21 and 61 side of the first battery cells 20A and 60A, and the negative external terminals 31 and 62 of the second battery cells 20B and 60B. It may be arranged on the side.

In the said embodiment, 1st battery cell 20A, 60A and 2nd battery cell 20B, 60B illustrated as a case where all the structural members including the battery cover 3 are the same.
However, part of the battery lid 3 or other constituent members may have different shapes and sizes.

  In the said embodiment, the liquid injection part 15 was illustrated as a structure formed in the battery cover 3. FIG. However, the liquid injection part 15 may be formed on any side surface of the battery can 2 without being formed on the battery lid 3.

  In the said embodiment, it illustrated by the case where a lithium ion secondary battery cell was used as a battery cell which comprises a battery module. However, the battery module of the present invention can be configured using other secondary battery cells such as nickel hydride secondary battery cells and nickel cadmium secondary battery cells. In addition to the secondary battery cell, a lithium ion capacitor can be applied.

Moreover, the shape of the cleavage valve 12 is not limited to the illustration of embodiment, It can be made into arbitrary shapes.
In addition, the battery module of the present invention can be variously modified and configured within the scope of the invention. In short, the power generation element group having the positive and negative electrode plates and the positive and negative electrodes The positive and negative current collectors connected to the electrode plate are accommodated in the battery container, the electrolyte is injected into the battery container, and the positive and negative external terminals connected to the positive and negative current collectors are A cleavage valve that is arranged on one side of one side of the battery container and on the other side opposite to the one side, and that cleaves and releases the gas in the battery container when the internal pressure in the battery container exceeds a predetermined value Has a plurality of battery cells arranged on one side of the battery container between the positive and negative external terminals, and the adjacent battery cells have the positive and negative external terminals opposed to the opposite polarity external terminals. In the arranged battery module, one of the adjacent battery cells is The cleavage valve is disposed near the positive electrode external terminal side on one side of the battery container, and the other adjacent battery cell may be any one as long as the cleavage valve is disposed near the negative electrode external terminal side on one side of the battery container. .

DESCRIPTION OF SYMBOLS 10, 50 Battery module 2, 83 Battery can 3, 84 Battery cover 6 Power generation element group 11 Bus bar 12 Cleavage valve 15 Injection part 20A, 60A 1st battery cell 20B, 60B 2nd battery cell 21, 61 Positive electrode external terminal 31, 62 Negative electrode external terminal 40 Duct for discharge 80 Battery cell

Claims (6)

A power generation element group having positive and negative electrode plates, and positive and negative current collector plates connected to the positive and negative electrode plates are housed in a battery container,
An electrolyte is injected into the battery container,
Positive and negative external terminals connected to the positive and negative current collector plates are arranged on one end side of one side surface of the battery container and on the other end side facing the one end side,
A cleavage valve that cleaves and releases gas in the battery container when the internal pressure in the battery container exceeds a predetermined value is disposed on the one side surface of the battery container between the positive and negative external terminals. A plurality of battery cells,
In the battery module in which the battery cells adjacent to each other are arranged with the positive and negative external terminals facing the opposite external terminals of the other party,
One of the adjacent battery cells has the cleavage valve disposed on the side of the positive electrode external terminal on one side of the battery container, and the other of the adjacent battery cells has the cleavage valve on one side of the battery container. A battery module, wherein the battery module is disposed closer to the negative external terminal side.   2. The battery module according to claim 1, between the cleavage valve and the negative electrode external terminal on one side surface of the battery container of the one battery cell, and on one side surface of the battery container of the other battery cell. A battery module, wherein a liquid injection part for injecting the electrolytic solution is provided between the cleavage valve and the positive electrode external terminal.   3. The battery module according to claim 1, further comprising a duct that is disposed on the cleavage valve of the one and the other battery cells and that discharges gas released from the cleavage valve, and the duct. Is attached to one side surface of the battery container around each of the cleavage valves with the upper part of each of the cleavage valves sealed from the outside.   4. The battery module according to claim 1, wherein each of the cleavage valves has a size in a longitudinal direction connecting the positive electrode external terminal and the negative electrode external terminal arranged on one side surface of the battery container. 5. The battery module is formed in an elongated shape larger than the size in the short direction perpendicular to the longitudinal direction.   5. The battery module according to claim 1, wherein a distance from the positive electrode external terminal of the one battery cell to a center of the cleavage valve, and the negative electrode external terminal of the other battery cell. A battery module characterized in that the distance to the center of the cleavage valve is equal. 6. The battery module according to claim 1, wherein each of the battery containers includes a cylindrical battery can having a bottom and an opening at the top, and closing the opening of the battery can. A battery module comprising a battery lid attached to a battery can, wherein the positive and negative external terminals and the cleavage valve are arranged on the battery lid.

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