JP7010671B2 - Lithium ion battery module - Google Patents

Description

The present invention relates to the structure of a lithium ion battery module.

In recent years, lithium-ion battery modules are often used as a power supply source for products such as notebook computers and smartphones, but accidents caused by ignition from the battery modules have become a problem. Ignition from the battery module is mainly caused by a short circuit between the anode and the cathode in the battery cell of the battery module, which causes a thermal runaway through an abnormal temperature rise of the battery cell.

Therefore, various measures have been proposed to suppress thermal runaway of the battery cell (see Patent Document 1). However, it is difficult to reliably prevent thermal runaway by improving the internal structure of the battery cell or the like.

Japanese Unexamined Patent Publication No. 2017-1233224

An object of the present invention is to provide a lithium ion battery module having a structure capable of suppressing thermal runaway caused by an internal short circuit of a battery cell, or a chain or ignition of thermal runaway.

The present invention has two forms for suppressing thermal runaway, chain of thermal runaway, and ignition of the lithium ion battery module. The first form is made from the viewpoint of suppressing the thermal runaway of the battery cell, and the second form is the heat even if the thermal runaway occurs in some of the battery cells in the lithium ion battery module. It was made from the viewpoint of suppressing the runaway from being chained to other battery cells.

The first embodiment of the lithium ion battery module according to the present invention is housed in a common heat conductive cell box in a state where a plurality of battery cells are arranged in the same plane in parallel with each other facing the same direction. The cell box is provided with a cell unit, the cell box has a cell accommodating portion for individually accommodating each of the battery cells, and the heat of each battery cell is transferred to the cell box. The inner surface of the cell accommodating portion is in contact with the cell body of the battery cell. Here, the "thermally conductive cell box" means a cell box made of a material having good thermal conductivity, such as aluminum.

That is, in the first embodiment of the present invention, a plurality of battery cells are housed in a heat conductive cell box to form an integrated cell unit having a heat capacity larger than that of the battery cells, and some battery cells in the cell unit are formed. When the temperature rises, the cell box absorbs the heat and suppresses the rapid temperature rise of some battery cells.

By the way, when the temperature of some of the battery cells rises, it is possible that the battery cells housed in the vicinity of the battery cells may be affected by the heat and cause thermal runaway. Therefore, in the first embodiment, an air layer or a heat insulating layer for reducing the heat transfer efficiency between the cell bodies of the battery cells is formed between the cell bodies of the battery cells adjacent to each other in the cell unit. May be. Then, when the temperature of a specific battery cell rises, the battery cell adjacent to the battery cell is prevented from being affected by the heat and causing thermal runaway.

In the first embodiment, a plurality of the cell units are arranged in the same plane so that the directions of the battery cells of the adjacent cell units are opposite to each other, and the two cell units adjacent to each other are arranged. A contact plate for electrically connecting all the battery cells is provided, and all the battery cells of the same cell unit are connected in parallel to each other by the contact plate, and two adjacent cell units of the same cell unit are connected in parallel. The battery cells may be connected in series with each other. Then, it becomes possible to connect a plurality of cell units in series while arranging them in a plane to provide a voltage supply capacity according to the application.

In a preferred embodiment of the above case, at least one surface side of the cell unit is covered with an insulating cover, wherein the insulating cover is located at a position corresponding to each one end of the battery cell. It has an opening that exposes one end of each, and is configured so that the outer surfaces of the cell boxes of the adjacent cell units do not come into contact with each other.

A second embodiment of the lithium ion battery module according to the present invention comprises a cell unit in which a plurality of battery cells are housed in a plurality of cell housing portions spatially separated from each other, and the cell unit is housed in the cell. Each part faces a common exhaust path with a contact plate having an opening and a heat insulating sealing member, and high-temperature gas is ejected from the battery cell in which thermal runaway has occurred to accommodate the battery cell. When the pressure in the cell accommodating portion rises, the sealing member interposed between the cell accommodating portion and the exhaust passage is opened so as to communicate the cell accommodating portion and the exhaust passage. The high temperature gas is configured to be exhausted to the outside through the exhaust passage.

That is, in the above-mentioned second embodiment of the present invention, each of the cell accommodating portions faces a common exhaust path with a contact plate having an opening and a heat insulating sealing member separated from each other so that the battery causes thermal runaway. When the high temperature gas is ejected from the cell and the pressure in the cell accommodating portion accommodating the battery cell rises, the sealing member interposed between the cell accommodating portion and the exhaust passage opens, and the high temperature gas in the cell accommodating portion is opened. Is exhausted to the outside through the exhaust passage. At this time, a heat insulating sealing member is interposed between the other cell accommodating portion and the exhaust passage without opening, and the influence of the high temperature gas flowing through the exhaust passage is accommodated in the other cell accommodating portion. It is configured so that it does not reach the existing battery cells.

In the second embodiment, it is preferable that the wall surface forming the exhaust passage or a part of the wall surface is formed of a heat radiating plate made of a heat conductive material. Then, the heat of the high-temperature gas flowing through the exhaust passage can be cooled by the heat sink, and the risk of ignition can be reduced. Furthermore, the risk of ignition can be reduced by narrowing the exhaust passage by bending the end of the heat sink and limiting the inflow of oxygen from the outside of the module.

Further, the cell unit is housed in a common cell box in a state where a plurality of battery cells are arranged in the same plane in parallel with each other facing the same direction, and one surface side of the cell unit is covered with an insulating cover. When it is covered, an opening is provided in the insulating cover at a position corresponding to each end of the battery cell to expose the one end of the battery cell, and the upper surface of the insulating cover is covered. A heat insulating sheet that seals the opening is used as the sealing member, and a notch that breaks when the pressure in the cell accommodating portion rises is provided at a position corresponding to each of the openings of the heat insulating sheet. Thereby, the above-mentioned second form can be realized.

In the first embodiment of the present invention, a plurality of battery cells are housed in a heat-conducting cell box to form an integrated cell unit having a heat capacity larger than that of the battery cells, and when the temperature of some of the battery cells rises. By absorbing the heat in the cell box, the rapid temperature rise of some battery cells is suppressed, so that the occurrence of thermal runaway of the battery cells is suppressed.

In the second aspect of the present invention, when a high temperature gas is ejected from a battery cell in which a thermal runaway has occurred and the pressure in the cell accommodating portion accommodating the battery cell rises, the space between the cell accommodating portion and the exhaust passage is increased. A sealing member intervening in the cell is opened, and the high-temperature gas in the cell accommodating portion is exhausted to the outside through the exhaust passage, while a heat insulating sealing member is opened between the other cell accommodating portion and the exhaust passage. It is configured so that the influence of the high temperature gas flowing through the exhaust passage does not reach the battery cells housed in other cell housings, so even if a thermal runaway occurs in some battery cells, it is configured so that it does not intervene. It is possible to suppress the occurrence of thermal runaway in a chain reaction in other battery cells. Further, the risk of ignition can be reduced by forming the wall surface forming the exhaust passage or a part of the wall surface with a heat radiating plate made of a heat conductive material.

It is a figure which shows one Example of the cell unit which has the structure which suppresses thermal runaway of a battery cell, (A) is a perspective view, (B) is a sectional view at the XX position of (A). It is a figure which shows the cell box of the cell unit of the same Example, (A) is the perspective view, (B) is the sectional view at the YY position of (A), (C) is the perspective view of the back surface side. It is a figure for demonstrating another example of the structure of a cell box, (A) is a sectional view which shows the air layer formed by a groove, (B) and (C) are for arrangement of different cell accommodating parts. It is a top view which shows the position of a groove. It is a figure for showing still another example of the structure of a cell box, (A) is a sectional view which shows the air layer (insulation layer) formed by a hole, (B) and (C) are different cells respectively. It is a top view which shows the position of the hole with respect to the arrangement of the accommodating part. It is a figure which shows the example which arranges two cell units in a plane and connects them in series, (A) is a perspective view, (B) is a sectional view. It is a figure which shows the embodiment which arranges a large number of cell units in a plane and connects them in series, (A) is a perspective view, (B) is a circuit block diagram in a battery module realized by it. It is a figure which shows an Example of the lithium ion battery module which has the structure which suppresses the chain of thermal runaway of a battery cell, (A) is a perspective view, (B) is a sectional view. It is a perspective view which shows the internal structure of the same Example. It is an exploded perspective view of the same Example. It is a conceptual diagram for demonstrating the concept that the chain of thermal runaway is suppressed by the same Example. It is a figure which shows the other example of the notch of the heat insulating sheet of the same Example, (A) is a plan view of the heat insulating sheet, (B) is a conceptual diagram which shows the flow direction of high temperature gas from an open heat insulating sheet. Is. It is a figure for demonstrating the concept of constructing the lithium ion battery module of the structure which suppresses the chain of thermal runaway using the square-shaped battery cell, (A) is the perspective view of the square-shaped battery cell, (A). B) and (C) are perspective views showing a stage in the middle of constructing the lithium ion battery module. (A) is a perspective view showing the structure of the cell unit composed of FIGS. 12 (B) and 12 (C), and (B) is a diagram for explaining the concept that the chain of thermal runaway is suppressed by the structure. Is. It is a figure for demonstrating the concept of constructing the lithium ion battery module of the structure which suppresses the chain of thermal runaway using the polymer battery cell, (A) is the perspective view of the polymer battery cell, (B) is lithium. It is a perspective view which shows the step in the process of constructing an ion battery module, and (C) is a figure for demonstrating the concept that the chain of thermal runaway is suppressed by the structure. It is sectional drawing which shows the other example of the structure of the cell unit connected in series.

Hereinafter, embodiments of the lithium ion battery module according to the present invention will be described.

1 and 2 show an example of the structure of the cell unit constituting the lithium ion battery module.

The cell unit 1 is formed in a cell box 2 having a plurality of cell accommodating portions 4, a plurality of battery cells 10 housed in each cell box 2, and a cell box 2 so as to cover a part of the outer surface of the cell box 2. It comprises an attached insulating cover 14.

The cell accommodating portion 4 of the cell box 2 is a recess having an opening for inserting the battery cell 10 on one surface side of the cell box 2. An opening 8 having an inner diameter smaller than the inner diameter of the cell accommodating portion 4 is provided on the bottom surface of the cell accommodating portion 4. The battery cell 10 is a cylindrical cell having an anode 12 at one end, and each battery cell 10 has the cell accommodating portion 4 so that the anode 12 faces the opening side (upper side in FIG. 1B) of the cell accommodating portion 4. It is fitted inside. The opening 8 is for exposing the cathode of each battery cell 10.

The insulating cover 14 is attached to the cell box 2 so as to cover the surface side of the outer surface of the cell box 2 where the opening of the cell accommodating portion 4 is provided, that is, the anode side of the battery cell 10. Hereinafter, the side of the cell unit 1 covered with the insulating cover 14 is referred to as an “anode side”, and the side of the cell unit 1 with the cell box 2 exposed from the insulating cover 14 is referred to as a “cathode side”.

The insulating cover 14 is provided with an opening 16 for exposing the anode of the battery cell 10. The inner diameter of the opening 16 is designed to be smaller than the inner diameter of the cell accommodating portion 4.

The cell box 2 is made of a metal material having good thermal conductivity, such as aluminum. The insulating cover 14 is made of an insulating material such as silica.

The inner diameter of the cell accommodating portion 4 of the cell box 2 is designed to be substantially the same as the outer diameter of the cell body of the battery cell 10, and is configured so that heat is well transferred between the battery cell 10 and the cell box 2. ing. As a result, when the temperature of some of the battery cells 10 rises, the heat of the battery cells 10 is absorbed by the entire cell box 2, and the protrusion of some of the battery cells 10 is suppressed from rising in temperature. .. As a result, thermal runaway of the battery cell 10 is suppressed.

Further, as shown in FIG. 3, a groove 22 is provided on the wall surface of the inner peripheral surface of the cell accommodating portion 4 that is interposed between the adjacent cell accommodating portions 4, and is accommodated in the cell accommodating portions 4 adjacent to each other. An air layer may be formed between the battery cells 10. As a result, when the temperature of some of the battery cells 10 rises, the influence on the battery cells 10 in the vicinity thereof can be reduced.

The same effect as the structure of FIG. 3 can also be obtained by providing a hole 24 in the partition wall between the cell accommodating portions 4 adjacent to each other, as shown in FIG. A heat insulating layer may be formed between the battery cells 10 housed in the cell housing portions 4 adjacent to each other by filling such a hole 24 with a heat insulating material.

In the lithium ion battery module of this embodiment, as shown in FIG. 5, two cell units 1 are arranged on the same plane so that the directions of the anode side and the cathode side are opposite to each other, and one of them is arranged. The anode of the battery cell 10 exposed on the anode-side surface of the cell unit 1 through the opening 16 and the cathode of the battery cell 10 exposed on the cathode-side surface of the other cell unit 1 through the opening 8. By conducting conduction using the flat plate-shaped contact plate 26 of the above, two cell units 1 composed of parallel connection of a plurality of battery cells 10 can be connected in series. At positions corresponding to the openings 8 and 16 of the contact 26, a contact terminal 28 for making a contact with the anode 12 or the cathode of the battery cell 10 is provided.

Of the cell units 1 arranged in a plane as shown in FIG. 5, the insulating cover 14 of the other cell unit 1 comes into contact with the exposed portion of the cell box 2 of the cell unit 1. The cell boxes 2 are configured so as not to come into contact with each other and electrically conduct electricity.

By using the above arrangement and connection method, as shown in FIG. 6, a larger number of cell units 1 can be arranged in a plane and connected in series. The number of cell units 1 arranged in a plane is determined by the magnitude of the required supply voltage.

In the embodiment described above, the insulating cover 14 is provided only on the anode side of the cell unit 1, but the present invention is not limited to this, and as shown in FIG. An insulating cover 14'may also be provided on the cathode side. In this case, it is preferable that the insulating cover 14'is provided with an opening 16'for exposing the cathode of the battery cell 10.

Next, an embodiment of a lithium ion battery module having a structure for suppressing the chain of thermal runaway of the battery cell 10 will be described.

As shown in FIG. 7, in the lithium ion battery module 100 of this embodiment, as shown in FIG. 6, a plurality of cell units 1 arranged in a plane and connected in series with each other are arranged in a plane and connected to each other in series with the outer frames 102 and 2. It is housed in a housing composed of a heat sink 104. The number of cell units 1 may be any number, and may be only one.

As shown in FIG. 8, a heat insulating sheet 106 is attached as a sealing member to the anode-side surface and the cathode-side surface of the cell unit 1. The openings 16 and 8 provided on the anode-side surface and the cathode-side surface of the cell unit 1 are sealed by a heat insulating sheet 106. As the heat insulating sheet 106, a sheet-like member having a heat resistance of 500 to 600 ° C. or higher, for example, NASBIS (a product of Panasonic Corporation), which is a sheet-like material composed of silica airgel and fibers, can be used. .. In addition, a member made of silica cloth, glass wool, or glass fiber can also be used.

As shown in FIG. 9, in this lithium ion battery module 100, the anode side of the cell unit 1 in which the heat insulating sheet 106 is attached to the surface on the anode side and the surface on the cathode side and fitted inside the outer frame 102. And two heat sinks 104 are fixed on the cathode side.

As shown in FIG. 7, a slight gap is formed between the heat insulating sheet 106 attached to the surface on the anode side and the surface on the cathode side of the cell unit 1 and the heat radiating plate 104, and this gap is formed. An exhaust passage 108 leading to the outside of the housing is configured through a gap (not shown) provided between the outer frame 102 and the heat sink 104. The distance between the gaps constituting the exhaust passage 108 is set to a dimension that makes it difficult for air to flow in from the outside of the housing, for example, 10 mm or less. That is, each cell accommodating portion 4 provided in the cell unit 1 faces the exhaust passage 108 with the heat insulating sheet 106 interposed therebetween.

The heat insulating sheet 106 is provided with a notch 110 at a position between the opening 16 on the anode side surface of the cell unit 1 and the exhaust passage 108. As shown in FIG. 10, the notch 110 is a heat insulating sheet when the pressure in the cell accommodating portion 4 accommodating the battery cell 10 increases due to the high temperature gas ejected from the battery cell 10 in which thermal runaway has occurred. It is for opening 106. When the heat insulating sheet 106 opens at the position of the cell accommodating portion 4 accommodating the battery cell 10 in which thermal runaway has occurred, the high temperature gas ejected from the battery cell 10 is discharged to the outside of the housing through the exhaust passage 108. Since the other cell accommodating portion 4 is still sealed by the heat insulating sheet 106, it is possible to prevent the battery cell 10 in which thermal runaway has not occurred from being exposed to the high temperature gas, and the chain of thermal runaway is suppressed. ..

The heat insulating sheet 106 can be adhered to the contact plate 26 with an adhesive, for example. In this case, in order to facilitate opening of the heat insulating sheet 106 due to an increase in pressure in the cell accommodating portion 4, it is preferable that the portion provided with the notch 110 is not bonded by an adhesive. However, the heat insulating sheet 106 does not necessarily have to be adhered to the contact plate 26, and is provided so as to seal the openings 8 and 16 on the anode side surface and the cathode side surface of the cell unit 1. It may be in any embodiment. For example, the heat insulating sheet 106 may be fixed to the insulating cover 14 on the anode side (also on the cathode side cover 14'if the cathode side cover 14'is provided).

In FIGS. 8 and 9, the heat insulating sheet 106 is provided with a cross-shaped notch 110, but the shape of the notch 110 is not particularly limited. Further, as shown in FIG. 11, when a thermal runaway occurs in the battery cell 10, the high temperature gas flowing out from the cell accommodating portion 4 is heat-insulated in a direction in which the cell accommodating portion 4 is not provided as much as possible. The shape of the notch 110 may be devised so that the sex sheet 106 opens.

In the examples shown in FIGS. 7 to 10, the cell unit 1 described with reference to FIGS. 1 to 6 is used, but the lithium ion battery module according to the present invention is not necessarily limited to this. It's not a thing. For example, the cell box constituting the cell unit does not have to have high thermal conductivity.

Further, the structure of the lithium ion battery module for suppressing the chain of thermal runaway according to the present invention can also be applied to the square battery cell 200 as shown in FIG. 12 (A). .. For example, a plurality of battery cells 200 are housed in a packaging container 202 made of a heat insulating material (see FIG. 12B) and housed in a common cell box 204 in the same direction to form a cell unit (see FIG. 12B). See FIG. 12 (C)).

In this embodiment, the packaging container 202 constitutes the cell accommodating portion and the sealing member. As the material of the packaging container 202, a sheet-like member having a heat resistance of 500 to 600 ° C. or higher, for example, NASBIS (a product of Panasonic Corporation), which is a sheet-like material composed of silica airgel and fibers, can be used. can. In addition, a member made of silica cloth, glass wool, or glass fiber can also be used.

The battery cell 200 is provided with an electrode and an explosion-proof valve on one end side, and when thermal runaway occurs in the battery cell 200, high-temperature gas is ejected from the explosion-proof valve on one end side. Therefore, as shown in FIG. 13A, one end side of the battery cell 200 of the packaging container 202 is sealed by, for example, heat welding, and the packaging container is heated by the high temperature gas from the battery cell 200 in which the thermal runaway occurs. When the pressure in the 202 suddenly rises, the sealing portion 202a is broken and the packaging container 202 is configured to open.

By arranging the heat radiating plate 212 along the arrangement direction of the battery cells 200 so as to face the sealing portion 202a of the packaging container 202 to form an exhaust passage, the high temperature from the battery cell 200 in which thermal runaway has occurred The gas is discharged to the outside through the exhaust passage, and the other battery cells 200 are protected from the high temperature gas by the heat insulating broadcasting container 202. As a result, the chain of thermal runaway of the battery cell 200 is suppressed. In FIG. 13, 206 is a cable for connecting the electrodes of each battery cell 200, and 208 and 210 are terminals provided at the end of the cable 206.

Further, the structure of the lithium ion battery module for suppressing the chain of thermal runaway according to the present invention can be applied to the flat plate type polymer battery cell 300 as shown in FIG. 14 (A). can. For example, as shown in FIGS. 14B and 14C, a plurality of battery cells 300 are individually stored in a cell box 302 having a plurality of cell accommodating portions to form a cell unit. The opening of each cell accommodating portion of the cell unit is sealed with the heat insulating sheet 304, and the heat sink 308 is arranged so as to face the heat insulating sheet 304.

A notch 306 is provided at the position of the opening of the cell accommodating portion of the heat insulating sheet 304, and the heat insulating sheet 304 at that position opens when the pressure in the cell accommodating portion rises due to the high temperature gas from the battery cell 300 in which thermal runaway occurs. Configure to do. A slight gap is left between the heat insulating sheet 304 and the heat radiating plate 308 to form an exhaust path for exhausting the high temperature gas flowing out from the opening of the heat insulating sheet 304 to the outside. As a result, even if thermal runaway occurs in some of the battery cells 300, the other battery cells 300 are protected from the high temperature gas by the heat insulating sheet 304, and the chain of thermal runaway is suppressed.

As the material of the heat insulating sheet 304, a sheet-like member having a heat resistance of 500 to 600 ° C. or higher, for example, NASBIS (a product of Panasonic Corporation), which is a sheet-like material composed of silica airgel and fibers, is used. be able to. In addition, a member made of silica cloth, glass wool, or glass fiber can also be used.

1 Cell unit 2,204,302 Cell box 4 Cell housing 8, 16 Opening 10,200,300 Battery cell 12 Anode 14 Insulating cover 22 Groove (air layer or heat insulating layer)
24 holes (air layer or heat insulating layer)
26 Contact plate 28 Contact terminal 100 Lithium-ion battery module 102 Outer frame 104,212,308 Heat sink 106,304 Insulation sheet (sealing member)
108 Exhaust passage 110, 306 Notch 202 Packaging container (sealing member)

Claims (3)

A cell unit is provided in which a plurality of battery cells are housed in a plurality of cell accommodating portions that are spatially separated from each other.
Each of the cell accommodating portions of the cell unit faces a common exhaust passage with a common heat insulating sheet.
The heat insulating sheet has a notch in a portion interposed between each of the plurality of cell accommodating portions and the exhaust passage.
When the high temperature gas is ejected from the battery cell in which the thermal runaway occurs and the pressure in the cell accommodating portion accommodating the battery cell rises, between the cell accommodating portion of the heat insulating sheet and the exhaust passage. A lithium-ion battery configured such that the notch provided in the intervening portion is broken to allow the cell accommodating portion and the exhaust passage to communicate with each other, and the high-temperature gas is exhausted to the outside through the exhaust passage. module. The lithium ion battery module according to claim 1 , wherein a part of the wall surface forming the exhaust passage is formed of a heat radiating plate made of a heat conductive material. The cell unit is housed in a common cell box in a state where a plurality of battery cells are arranged in the same plane in parallel with each other facing the same direction, and at least one surface side of the cell unit is covered with an insulating cover. It is something that has been
The insulating cover has an opening that exposes the end of the battery cell at a position corresponding to each end of the battery cell.
The heat insulating sheet covers the upper surface of the insulating cover and seals the opening.
The lithium ion battery module according to claim 1 or 2 , wherein the notch is provided at a position corresponding to each of the openings of the heat insulating sheet.

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