JP2012212558A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe battery module with an excellent electric characteristic, which restrains deterioration of an energy density.SOLUTION: In a battery module according to the present invention, a battery chamber, in which unit cells each having a first terminal and a second terminal are aligned so that emission parts of the second terminals are positioned in the same direction; and an exhaust duct for exhausting gas emitted from the emission parts outside the case are blocked by partitions. The emission parts are communicated with the exhaust duct via through holes provided on the partitions, and second collector plates, to which the second terminals are electrically connected, are folded on an alignment terminal end of the unit cell, extend toward an alignment start end of the unit cell, and are coupled with a second external terminal. The folded portions of the second collector plates are opposed to each other at a predetermined gap from at least the emission parts.

Description

  The present invention relates to a battery module configured by arranging a plurality of unit cells.

  In recent years, demand for secondary batteries such as nickel metal hydride, nickel cadmium, and lithium ion that can be repeatedly used is increasing from the viewpoint of resource saving and energy saving. Among these, lithium ion secondary batteries are characterized by high electromotive force and high energy density while being lightweight. For this reason, there is an increasing demand for power sources for driving various types of portable electronic devices such as mobile phones, digital cameras, video cameras, laptop computers, and mobile communication devices.

On the other hand, in order to reduce the amount of fossil fuel used and the amount of CO ₂ emitted, there is an increasing expectation for a battery module containing a plurality of unit cells as a power source for driving a motor of an automobile or the like.

  In the development of the battery module, as the capacity of the battery to be accommodated increases, the battery itself may generate heat and become high temperature depending on the form of use. Therefore, not only the safety of the battery itself but also the safety of the battery module in which they are assembled is more important. That is, in the battery, the internal pressure increases due to gas generated by overcharge, overdischarge, internal short circuit, or external short circuit, and in some cases, the battery case may burst. Therefore, in general, the battery is provided with a vent mechanism for venting gas, a safety valve, and the like to release the internal gas. At this time, smoke may be generated due to the exhausted gas, and there are problems in reliability and safety.

  In particular, in a battery module containing a plurality of batteries, the abnormal heat generation of one battery is likely to cause abnormal heating to the surrounding batteries in a chained manner, thereby increasing the possibility of preventing the failure. is important.

  As means for coping with the above problems, for example, a configuration in which an exhaust duct is provided in a battery module and the generated gas is discharged to the outside through the exhaust duct is disclosed (for example, see Patent Document 1).

JP 2010-140695 A

  In the structure having the exhaust duct as in Patent Document 1, it is preferable that the exhaust duct has a large internal space in order to exhaust the exhaust gas efficiently and safely to the outside of the battery module. However, if the internal space of the exhaust duct is large, the ratio of dead space (space in which no unit cell is provided) in the battery module is increased, leading to a decrease in energy density as the battery module.

  This invention is made | formed in view of this point, and it aims at providing the battery module which the fall of the energy density was suppressed and was excellent in safety | security.

  The battery module of the present invention is a battery module configured by housing a plurality of unit cells having a first terminal and a second terminal in a polyhedral case, and the case includes the second terminal. A battery chamber in which the unit cells are arranged so that the discharge portions are positioned in the same direction; and an exhaust duct for discharging the gas discharged from the discharge portion to the outside of the case, the battery chamber and the exhaust duct The discharge part is communicated with the exhaust duct by a through hole provided in the separator, and the second current collector connected to the second terminal is the unit cell. The second current collector plate is folded back at the array end side and extended toward the array start end side, and the folded portion of the second current collector plate is disposed opposite to at least the discharge portion with a predetermined gap. It is characterized by.

  According to such a configuration, when the gas is discharged from the discharge portion of the unit cell to the exhaust duct, the discharge portion of the unit cell and the current collector plate face each other. It contacts the high current collector plate and diffuses along the current collector plate. Therefore, the gas temperature can be instantaneously reduced by the heat dissipation effect of the current collector plate. Therefore, it is possible to reduce the volume of the exhaust duct, and it is possible to obtain a battery module that is excellent in safety by suppressing a decrease in energy density.

  This invention is made | formed in view of this point, The fall of an energy density is suppressed and the battery module excellent in safety | security can be provided.

Sectional drawing of the lithium ion secondary battery as a unit cell in embodiment of this invention (A) The exploded perspective view of a battery module in Embodiment 1 of this invention, (b) Sectional drawing of a battery module (A) The exploded perspective view of a battery module in Embodiment 2 of this invention, (b) Sectional drawing of a battery module (A) The exploded perspective view of a battery module in Embodiment 3 of this invention, (b) Sectional drawing of a battery module (A) The exploded perspective view of a battery module in Embodiment 4 of this invention, (b) Sectional drawing of a battery module (A) The exploded perspective view of a battery module in Embodiment 5 of this invention, (b) Sectional drawing of a battery module

  The battery module of the present invention is a battery module configured by housing a plurality of unit cells having a first terminal and a second terminal in a polyhedral case, and the case includes the second terminal. A battery chamber in which the unit cells are arranged so that the discharge portions are positioned in the same direction; and an exhaust duct for discharging the gas discharged from the discharge portion to the outside of the case, the battery chamber and the exhaust duct The discharge part is communicated with the exhaust duct by a through hole provided in the separator, and the second current collector connected to the second terminal is the unit cell. The second current collector plate is folded back at the array end side and extended toward the array start end side, and the folded portion of the second current collector plate is disposed opposite to at least the discharge portion with a predetermined gap. It is characterized by.

According to such a configuration, when the gas is discharged from the discharge portion of the unit cell to the exhaust duct, the discharge portion of the unit cell and the current collector plate face each other. It contacts the high current collector plate and diffuses along the current collector plate. Therefore, the gas temperature can be instantaneously reduced by the heat dissipation effect of the current collector plate. Therefore, even if the volume of the exhaust duct is made smaller, it is possible to avoid dangers such as ignition of the gas discharged from the unit cell, and furthermore, due to abnormal heat generation of one battery, abnormalities in surrounding batteries can be avoided. It is also possible to avoid heating being chained. Therefore, it is possible to reduce the volume of the exhaust duct, and it is possible to obtain a battery module that is excellent in safety by suppressing a decrease in energy density.

  In the battery module of the present invention, the first current collector connected to the first terminal is connected to the first external terminal, and the second current collector is connected to the second external terminal. The first external terminal and the second external terminal are preferably provided on the same outer surface of the case. In such a configuration, since the first external terminal and the second external terminal are located on the same surface, when connecting to the electric circuit outside the battery module, the connection work becomes easy and the proportion of the connection space is reduced. it can.

  Moreover, the battery module of this invention WHEREIN: It is preferable that the part by which the said 2nd collector plate was turned back has a fusing part in the location facing the said discharge part at least. By adopting such a configuration, when an abnormality occurs in the unit cell in the battery module and high-temperature gas is discharged, the portion facing the discharge portion is melted by the heat, and the second current collector plate All of the cells connected to can be isolated from the electric circuit.

  Moreover, the battery module of this invention WHEREIN: It is preferable that the said fusing part is comprised by making thickness of a said 2nd current collecting plate thin. By adopting such a configuration, when the above-described discharge of the high-temperature gas occurs, the fusing part facing the discharge part is easily blown, and all the unit cells connected to the second current collector plate are more reliably connected. Can be isolated from electrical circuits.

  Moreover, the battery module of this invention WHEREIN: It is preferable that the said separator is comprised integrally with a said 2nd collector plate. With such a configuration, the number of parts is reduced and assembly is facilitated. Furthermore, by arranging the current collector plate as a separator on the entire surface, it is possible to further reduce the number of parts and dead space, and further increase the area of the current collector plate in the exhaust duct, thereby further cooling the exhaust gas. An effect is obtained.

  Furthermore, in the configuration of the battery module, the plurality of unit cells are arranged in order from the first to the nth, and the first terminal and the second terminal are respectively the first current collector plate and the second current collector plate. And the first external terminal connected to the first current collector plate forms the shortest current path with the first unit cell among the unit cells. The second external terminal connected to the second current collector plate preferably forms the shortest current path with the n-th unit cell among the unit cells. In such a configuration, in addition to the effects described above, variations in circuit resistance with respect to each unit cell can be eliminated, so that battery characteristics can also be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment. Moreover, it can change suitably in the range which does not deviate from the range which has the effect of this invention. Furthermore, combinations with other embodiments are possible.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a battery (hereinafter referred to as “unit cell”) 100 used in a battery module according to an embodiment of the present invention. The battery module in the present invention is configured as an assembly of unit cells in which a plurality of unit cells 100 are arranged in at least one row.

For example, a cylindrical lithium ion secondary battery as shown in FIG. 1 can be adopted as the unit cell 100 constituting the battery module in the present invention. This lithium ion secondary battery may be a general-purpose battery used as a power source for portable electronic devices such as notebook computers. In this case, since a high-performance general-purpose battery can be used as a unit cell of the battery module, it is possible to easily improve the performance and cost of the battery module. In addition, the unit cell 100 includes a safety mechanism that releases gas to the outside of the battery when the pressure in the battery increases due to an internal short circuit or the like. Hereinafter, a specific configuration of the unit cell 100 will be described with reference to FIG.

  As shown in FIG. 1, an electrode group 4 in which a positive electrode 2 and a negative electrode 1 are wound through a separator 3 is accommodated in a battery case 7 together with a non-aqueous electrolyte. An upper insulating plate 9 and a lower insulating plate 10 are disposed above and below the electrode group 4, the positive electrode 2 is joined to the filter 12 through the positive electrode lead 5, and the negative electrode 1 is connected through the negative electrode lead 6. It is joined to the bottom of the battery case 7 which also serves as a negative electrode terminal.

  The filter 12 is connected to the inner cap 13, and the protruding portion of the inner cap 13 is joined to the metal valve body 14. Further, the valve body 14 is connected to a terminal plate 8 that also serves as a positive electrode terminal. The terminal plate 8, the valve body 14, the inner cap 13, and the filter 12 are integrated and sealed by caulking the opening of the battery case 7 via the gasket 11.

  When an internal short circuit or the like occurs in the unit cell 100 and the pressure in the unit cell 100 increases, the valve body 14 swells toward the terminal plate 8 and the inner cap 13 and the valve body 14 are disconnected from each other. Is cut off. When the pressure in the unit cell 100 further increases, the valve body 14 is broken. Thereby, the gas generated in the unit cell 100 is discharged to the outside through the opening 12a of the filter 12, the opening 13a of the inner cap 13, the tear of the valve body 14, and the discharge part 8a of the terminal plate 8. Is done.

  In addition, the safety mechanism which discharges | emits the gas generated in the unit cell 100 outside is not limited to the structure shown in FIG. 1, The thing of another structure may be used.

(Embodiment 1)
Next, Embodiment 1 of the present invention will be described in detail with reference to FIG. Fig.2 (a) shows the disassembled perspective view of the battery module in Embodiment 1 of this invention. Moreover, FIG.2 (b) shows sectional drawing of the battery module in Embodiment 1 of this invention.

  A plurality of (three in the figure) cylindrical unit cells 100 arranged in a row are accommodated in a case including a case container 40 and a lid 50 to form a battery module 200. Here, the negative electrode current collecting plate 30 is disposed on the inner bottom surface of the case container 40, and a plurality of unit cells arranged in a row are accommodated on the negative electrode current collecting plate 30. As shown in FIG. 1, the terminal plate 8 serving as the positive terminal of the unit cell 100 has a discharge portion 8a, and the discharge portions are arranged on the same surface. Separating plates 70 having through holes 70 a corresponding to the respective terminal plates 8 are placed on top of the plurality of unit cells 100. Therefore, in the battery module 200, the battery chamber 80 and the exhaust duct 60 are partitioned by the separator plate 70. Further, the positive electrode current collector plate 20 is disposed on the upper part of the separator plate 70, and the open end of the case container 40 is sealed with a lid 50 so as to cover them.

  The terminal plate 8 serving as the positive electrode terminal of each unit cell 100 is inserted into the through hole 70 a of the separator plate 70 and is electrically connected by being brought into close contact with the positive electrode current collector plate 20. Moreover, the negative electrode terminal (bottom part of the battery case 7) of each unit cell 100 is arrange | positioned in contact with the negative electrode current collecting plate 30, and is electrically connected. Thereby, each unit cell 100 is electrically connected in parallel by the positive electrode current collector plate 20 and the negative electrode current collector plate 30.

The discharge portion 8 a of the unit cell 100 communicates with the exhaust duct 60 surrounded by the separator plate 70 and the lid 50 through the through hole 20 a of the positive electrode current collector plate 20. Thereby, the high temperature gas discharged from the discharge portion 8 a of the unit cell 100 is discharged to the exhaust duct 60 through the through hole 20 a of the positive electrode current collector plate 20. Further, since the exhaust duct 60 is partitioned in a substantially sealed state with respect to the plurality of unit cells 100 by the separator plate 70, the high-temperature gas discharged to the exhaust duct 60 is exposed to the surrounding unit cells 100. Without discharge, the battery 50 can be discharged from the discharge port 50 a provided in the lid 50 through the exhaust duct 60.

  The unit cells 100 are arranged in a row from the arrangement start end close to the case surface where the external terminals are arranged to the arrangement end. Here, the positive electrode current collector plate 20 is electrically connected to the positive electrode terminals of all the unit cells 100 from the arrangement start end to the arrangement end. Further, the positive electrode current collector plate 20 is bent and folded back and extended on the arrangement end side. Further, the folded portion of the positive electrode current collector plate 20 is disposed so as to face the discharge portion 8a of the unit cell 100 and have a predetermined distance. Therefore, when gas is discharged from the discharge part 8a of the unit cell 100 to the exhaust duct 60, the discharged gas instantaneously contacts the positive current collector plate 20 facing the discharge part 8a and diffuses along the positive current collector plate 20. And discharged from the discharge port 50a to the outside of the battery module 200. Therefore, the exhaust gas can be quickly cooled by the heat dissipation effect of the positive electrode current collector plate 20, and the volume of the exhaust duct 60 can be reduced.

  In order to obtain such a heat dissipation effect more efficiently, the material of the positive electrode current collector plate 20 is preferably a material having good electrical conductivity and good thermal conductivity. For example, copper, aluminum and the like are preferable.

  One end of the positive electrode current collector plate 20 extends to the outside from the discharge port 50a of the lid 50, and is exposed to the outside of the battery module 200 as the positive electrode external terminal 20b. One end of the negative electrode current collector plate 30 extends from the case container 40 to the outside and is exposed to the outside of the battery module 200 as a negative electrode external terminal 30b. The battery modules 200 are connected to each other by these external terminals, and are connected to external electric components. In such a configuration, the positive external terminal 20b and the negative external terminal 30b are preferably located on the same surface of the battery module 200. Thereby, the workability | operativity at the time of the said electrical connection can be improved.

  Further, in the present embodiment, the unit cells 100 are arranged from the arrangement start end close to the case surface where the external terminals are arranged to the arrangement end in a row, and are electrically in parallel with the positive electrode current collector plate 20 and the negative electrode current collector plate 30. It is connected. Here, in FIG. 2, the positive external terminal 20 b forms the shortest current path with the unit cell (the leftmost in the drawing) of the unit cells 100, and the negative external terminal 30 b The shortest current path is formed with the cell at the beginning of the array (the rightmost side in the figure) among the above unit cells. Thereby, the circuit resistance between the positive electrode external terminal 20b and the negative electrode external terminal 30b becomes substantially equal to each unit cell, and the battery characteristics are also improved.

  The battery module 200 is preferably insulated from the outside except for the positive external terminal 20b and the negative external terminal 30b. Therefore, it is preferable that the lid 50 and the case container 40 in the battery module 200 are made of an insulating material. Specifically, a glass epoxy resin or the like is more preferable from the viewpoints of strength and heat resistance.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described in detail with reference to FIG. 3A is an exploded perspective view of the battery module according to the second embodiment of the present invention, and FIG. 3B is a cross-sectional view of the battery module according to the second embodiment. In the present embodiment, the positive electrode current collector plate 20 is a portion where the positive electrode current collector plate 20 is folded back, and a fusing part 20c is provided at a location facing the discharge part 8a. Here, the fusing part 20c is formed by making a part of the positive electrode current collector plate 20 thin. The high-temperature gas discharged from the discharge portion 8a of the unit cell 100 is intensively ejected to a portion facing the discharge portion 8a at the folded portion of the positive electrode current collector plate 20. Therefore, by providing the fusing part 20c at that location and instantaneously fusing 20c at the time of abnormality, all the unit cells 100 connected to the positive electrode current collector plate 20 inside the battery module 200 can be isolated from the electric circuit. As a result, even if an abnormality occurs in the single cell unit 100 inside the battery module 200, it is possible to avoid the possibility of causing the abnormal heating to the surrounding batteries in a chain and expanding the malfunction. .

(Embodiment 3)
Next, Embodiment 3 of the present invention will be described in detail with reference to FIG. 4A is an exploded perspective view of the battery module according to Embodiment 3 of the present invention, and FIG. 4B is a cross-sectional view of the battery module according to Embodiment 3 of the present invention. In the present embodiment, the positive electrode current collector plate 20 is configured such that the folded portion of the positive electrode current collector plate 20 is narrow. Therefore, since the positive electrode current collector plate 20 facing the discharge part 8a is narrow, it functions as a fusing part 20c. Similarly to the above, by fusing the fusing part 20c in the event of an abnormality, the positive electrode current collecting plate inside the battery module 200 All the unit cells 100 connected to 20 can be isolated from the electric circuit. Therefore, it is possible to avoid the possibility that the abnormal heating of the surrounding batteries is induced in a chain due to the abnormality of the unit cell 100 in the battery module 200 to enlarge the malfunction.

  In the present embodiment, all the folded portions are configured to be narrow, but at least a portion facing the discharge portion 8a may be configured to be narrow.

(Embodiment 4)
Next, Embodiment 4 of the present invention will be described in detail with reference to FIG. FIG. 5A is an exploded perspective view of the battery module according to Embodiment 4 of the present invention, and FIG. 5B is a cross-sectional view of the battery module according to Embodiment 4 of the present invention. In the present embodiment, the positive electrode current collector plate 20 is configured such that the folded portion of the positive electrode current collector plate 20 is narrow, and the portion facing the discharge portion 8a is thinned so that the fusing portion 20c is formed. Provided. Therefore, since the positive electrode current collector plate 20 facing the discharge portion 8a is narrow and thin, the portion functions as the fusing portion 20c. Therefore, similarly to the above, 20c is melted at the time of abnormality, and all the unit cells 100 connected to the positive electrode current collector plate 20 in the battery module 200 can be isolated from the electric circuit. As a result, it is possible to avoid the possibility that the abnormal heating is chain-induced due to the abnormality of the one-cell unit cell 100 in the battery module 200 and the trouble is enlarged. Further, in the present invention, since it is narrow and thin, it can be a safe battery with higher fusing property.

  In the second to fourth embodiments of the present invention, the fusing part 20c of the positive electrode current collector plate 20 is configured to be thin or narrow, but is not limited to this, and other materials that are easily fusing, for example, May be connected.

(Embodiment 5)
Next, Embodiment 5 of the present invention will be described in detail with reference to FIG. 6A is an exploded perspective view of the battery module according to the fifth embodiment of the present invention, and FIG. 6B is a cross-sectional view of the battery module according to the fifth embodiment. In the battery module of this embodiment, the positive electrode current collector plate 20 is connected to each unit cell 100 and partitions the battery chamber and the exhaust duct so as to be substantially sealed with respect to the unit cell 100. Therefore, the positive electrode current collector plate 20 of this embodiment also has a function as a separator. As a result, the number of parts can be reduced and the proportion of dead space can be reduced. Furthermore, the cooling effect of the exhaust duct can be increased.

  In the description of the embodiment of the present invention, the exhaust duct is provided on the positive electrode terminal side of the unit cell. However, when the exhaust part is provided on the negative electrode terminal, the exhaust duct may be provided on the negative electrode terminal side.

  Further, in the embodiment of the present invention, the description has been given using the battery module in which the unit cells are arranged in a line. However, the battery module is configured so that an assembly of unit cells arranged in a line and connected in parallel is included in a plurality of columns. It doesn't matter.

  The present invention can provide a battery module with improved safety. Therefore, it is particularly useful as a driving power source for automobiles, electric motorcycles, electric playground equipment, and the like.

DESCRIPTION OF SYMBOLS 1 Negative electrode 2 Positive electrode 3 Separator 4 Electrode group 5 Positive electrode lead 6 Negative electrode lead 7 Battery case 8 Terminal board 8a Exhaust part 9 Upper insulating board 10 Lower insulating board 11 Gasket 12 Filter 13 Inner cap 12a, 13a Opening 14 Valve body 20 Positive electrode collection Electrode plate 20b Positive electrode external terminal 20c Fusing part 30 Negative electrode current collector plate 30b Negative electrode external terminal 40 Case container 50 Lid 50a Discharge port 60 Exhaust duct 70 Separation plate 20a, 70a Through hole 80 Battery chamber 100 Unit cell 200 Battery module

Claims (6)

A battery module configured by accommodating a plurality of unit cells having a first terminal and a second terminal in a polyhedral case,
The case includes a battery chamber in which the unit cells are arranged so that a discharge portion of the second terminal is positioned in the same direction, and an exhaust duct that discharges the gas discharged from the discharge portion to the outside of the case, The battery chamber and the exhaust duct are partitioned by a separator,
The discharge part communicates with the exhaust duct through a through hole provided in the separator,
The second current collector plate connected to the second terminal is folded back at the cell array end side and extends to the cell array start end side,
The folded portion of the second current collector plate is disposed opposite to the discharge portion with a predetermined gap. A first current collector connected to the first terminal is connected to a first external terminal;
The second current collector plate is connected to a second external terminal;
The battery module according to claim 1, wherein the first external terminal and the second external terminal are provided on the same outer surface of the case.   3. The battery module according to claim 1, wherein the folded portion of the second current collector plate has a fusing portion formed at least at a location facing the discharge portion.   The battery module according to claim 3, wherein the fusing part is formed by reducing the thickness of the second current collector plate.   The battery module according to any one of claims 1 to 4, wherein the separator plate is configured integrally with the second current collector plate. The plurality of unit cells are arranged in order from the first to the nth, and the first terminal and the second terminal are electrically connected in parallel with the first current collector plate and the second current collector plate, respectively. And
The first external terminal connected to the first current collector plate forms the shortest current path with the first unit cell among the unit cells,
The second external terminal connected to the second current collector plate forms a shortest current path with the n-th unit cell among the unit cells. The battery module as described.