Patent Application
20100266880
The present invention relates to a battery module in which a failure such as heat generation occurring in one battery does not affect other batteries, and a battery pack using the battery module.
Recently, from the viewpoint of resource savings and energy savings, demands for secondary batteries such as nickel hydrogen, nickel cadmium and lithium ion secondary batteries, which can be used repeatedly, are increased. Among them, the demand for the lithium ion secondary battery is expanded as a driving power source for various kinds of portable electronic apparatuses and mobile telecommunication apparatuses, for example, portable telephones, digital cameras, video cameras, and notebook-sized personal computers, and the like, because the lithium ion secondary battery has high electromotive force and large energy density although it has light weight. On the other hand, in order to reduce the amount of fossil fuel to be used and the exhaustion amount of CO2, a battery module is developed as a power source for driving a motor of an automobile or the like. The battery modules are combined so as to be capable of obtaining a desirable voltage and volume.
In the development thereof, with the trend toward large energy density of batteries, a battery itself may generate heat to high temperatures depending upon forms of use. Therefore, not only the safety of the battery itself but also the safety of a battery module and a battery pack using assembly of the batteries becomes more important.
In the above-mentioned batteries, the internal pressure of the battery is increased by a gas generated by overcharge, internal short-circuit or external short-circuit and a battery case may occasionally be ruptured. Therefore, in general, these batteries are provided with a vent mechanism, a vent hole, or the like, for extracting gases.
Conventionally, an example of a battery pack is disclosed. The battery pack includes rechargeable batteries, a filter part adsorbing inflammable materials, and an outer member covering the batteries and the filter part and having an exhaust hole from which contents filtered after passing through the filter part are exhausted to the outside is disclosed. This battery pack is capable of preventing smoke generation and ignition of the battery even if the contents are discharged from the battery (for example, Patent Document 1).
Furthermore, an example of a battery module individually accommodating batteries in a square-shaped battery accommodation part of a holder case made of synthetic resin is disclosed (for example, Patent Document 2).
However, in the battery pack disclosed in Patent Document 1, when a vent mechanism is operated due to a failure of one battery, it is not possible to prevent the surrounding batteries from being deteriorated consecutively by the ignition and rupture due to the blowout of gas. Therefore, in particular, in a battery module and a battery pack using a plurality of batteries, how to suppress the influence of the failure of one battery on the surrounding batteries is a problem to be solved.
Furthermore, in the battery module disclosed in Patent Document 2, the batteries can be connected stably by individually accommodating the batteries in the battery accommodation part. Furthermore, the battery module can hold the batteries in the battery accommodation part without shaking even under vibration or shock. In addition, the document discloses that uniform cooling can be carried out due to securing a cooling passage by heat radiation holes provided in the height direction of the batteries. However, the document does not disclose how to prevent the effect of one battery on the surrounding batteries if the one battery generates heat abnormally to cause ignition and rupture.
A battery module of the present invention includes a first enclosure, a second enclosure, and a plurality of batteries each having a vent hole and which are accommodated between the first enclosure and the second enclosure. A first partition member is provided to individually accommodate the batteries at a position facing the vent holes of the batteries in at least one of the first enclosure and the second enclosure.
With this configuration, the first partition member receives flame or the like produced by ignition of gas emitted from a vent hole of a battery with a failure, thus preventing the flame from directly striking the surrounding batteries. As a result, it is possible to prevent fire from spreading to the surrounding batteries, to prevent abnormal overheating of the surrounding batteries, and the like. Thereby, a battery module excellent in reliability and safety can be achieved.
Furthermore, the present invention has a configuration in which the above-mentioned battery modules are connected in tandem or in parallel as unit battery modules. Thus, fire cannot easily be spread between the unit battery modules even when the unit battery modules are stacked with each other, and a battery module having high safety and reliability can be achieved. Therefore, a battery module corresponding to a required voltage or a volume can be arbitrarily configured.
Furthermore, a battery pack of the present invention has a configuration in which the above-mentioned battery modules are accommodated in an exterior enclosure. Thus, a battery pack having a high versatility can be achieved.
Hereinafter, exemplary embodiments of the present invention are described with reference to drawings in which the same reference numerals are given to the same components. Note here that the present invention is not limited to the embodiments mentioned below as long as it is based on the basic features described in the description. Furthermore, in the below description, a non-aqueous electrolyte secondary battery (hereinafter, referred to as a “battery”) such as a lithium ion battery is described as an example of a battery. However, the battery is not limited to this example.
As shown in
Herein, positive electrode layer 1b includes a lithium-containing composite oxide such as LiCoO2, LiNiO2, and Li2MnO4, or a mixture thereof or a composite compound thereof, as the positive electrode active material. Positive electrode layer 1b further includes a conductive agent and a binder. As the conductive agent, positive electrode layer 1b may include graphite such as natural graphite and artificial graphite; and carbon black such as acetylene black, Ketjen black, channel black, furnace black, lampblack, thermal black, and the like. As the binder, positive electrode layer 1b may include PVDF, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, and the like.
As positive current collector 1a used in positive electrode 1, aluminum (Al), carbon, conductive resin, and the like, can be used.
As the non-aqueous electrolyte, an electrolyte solution obtained by dissolving a solute in an organic solvent, or a so-called a polymer electrolyte layer including the electrolyte solution and immobilized by a polymer can be used. The solute of the nonaqueous electrolyte includes LiPF6, LiBF4, LiClO4, LiAlCl4, LiSbF6, LiSCN, LiCF3SO3, LiN(CF3CO2), LiN(CF3SO2)2, and the like. An example of the organic solvent may include ethylene carbonate (EC), propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate (DMC), diethyl carbonate, ethyl methyl carbonate (EMC), and the like.
As negative current collector 11 of negative electrode 2, a metal foil of, for example, stainless steel, nickel, copper, and titanium, and a thin film of carbon and conductive resin can be used.
As negative electrode layer 15 of negative electrode 2, negative electrode active materials capable of reversibly absorbing and releasing lithium ions can be used. For example, carbon materials such as graphite, and negative electrode active materials having a theoretical capacity density of more than 833 mAh/cm3, such as silicon (Si), tin (Sn), and the like, can be used.
Hereinafter, a battery module in accordance with the first exemplary embodiment of the present invention is described in detail with reference to
As shown in
Then, as shown in
According to this exemplary embodiment, even if the temperature of one battery becomes higher due to abnormality and a high-temperature gas is emitted from the vent hole, it is possible to prevent the high-temperature gas from directly striking the surrounding batteries with the first partition member. As a result, it is possible to effectively prevent surrounding batteries from becoming higher in temperature consecutively. Furthermore, as the first partition member is higher, the radiant heat radiated from the side surface of the battery case can be blocked reliably, and therefore, the influence on the surrounding batteries can be suppressed.
Note here that this exemplary embodiment describes an example in which the battery module is configured by connecting the first enclosure and the second enclosure to the batteries. However, the configuration is not necessarily limited to this example. For instance, a battery module may have a configuration in which a first enclosure and a second enclosure are securely fixed via a supporting member (not shown) whose height is about the same as that of the batteries.
Furthermore, this exemplary embodiment describes an example in which the first and second enclosures and the first partition member are made of a heat-resistant member such as polycarbonate resin having a heat resistance of, for example, about 200° C. However, the configuration is not necessarily limited to this example. For example, only the first enclosure provided with the first partition member may be made of a heat-resistant member and the second enclosure may be made of a resin member such as polypropylene (PP) and polyethylene (PE) having a low heat resistance of, for example, around 100° C. Thus, the production cost can be reduced.
Herein, as the heat-resistant member, the following material can be used: polyphenylene sulfide (PPS) resin, polycarbonate (PC) resin, polyether ether ketone (PEEK) resin, phenol resin, UNILATE™, glass epoxy resin, ceramic, and resin foam. It is preferable that the above-mentioned resin contains filler such as carbon fiber and glass fiber. Thus, the mechanical strength of the enclosure can be improved by the filler to be contained. Alternatively, metal materials such as aluminum (Al), copper (Cu), iron (Fe), and nickel (Ni), which are coated with insulating resin, may be used. The metal material may have a plate shape or a mesh (network) shape. When the metal material has a mesh shape, high mechanical strength and light enclosure can be achieved. Furthermore, as an insulating resin, a heat-resistant member may not necessarily be used, and insulating resin that is cheaper and can be easily formed may be used.
Hereinafter, another example of a battery module in accordance with the first exemplary embodiment of the present invention is described with reference to
As shown in
In this case, first enclosure 210, second enclosure 220, first partition member 215 and second partition member 225 are made of the same heat-resistant member as that of first enclosure 110 and first partition member 115 of battery module 100. Since other components are the same as those of battery module 100, the description thereof is omitted herein.
According to the later example of this exemplary embodiment, even if the temperature of one battery becomes higher due to abnormality and a high-temperature gas is emitted from the vent hole, it is possible to prevent the high-temperature gas from directly striking the surrounding batteries by the first and second partition members. As a result, it is possible to effectively prevent surrounding batteries from becoming higher in temperature consecutively.
Hereinafter, a battery module in accordance with a second exemplary embodiment of the present invention is described in detail with reference to
As shown in
Since other components are the same as those of battery module 100, the description thereof is omitted herein.
According to this exemplary embodiment, even if the temperature of one of the batteries becomes higher due to abnormality and a high-temperature gas is emitted from the vent hole, the gas is exhausted from the air hole and the first and second partition members can prevent the gas from directly striking the surrounding batteries. Furthermore, since each of the batteries is completely accommodated by the first and second enclosures, so that the radiant heat radiated from the side surface of the battery cases can be reliably blocked. Therefore, it is possible to further suppress the influence on the surrounding batteries.
Note here that the above-mentioned exemplary embodiment descries an example of the battery module in which a plurality of batteries are connected in parallel. However, the configuration is not necessarily limited to this example. For example, a plurality of batteries 430 are connected in series as shown in
According to the above-mentioned configuration, it is possible to achieve battery module 400 capable of obtaining the same effect as that in the second exemplary embodiment and excellent in versatility.
Hereinafter, a battery module in accordance with a third exemplary embodiment of the present invention is described in detail with reference to
As shown in
That is to say, as shown in
In this configuration, it is important that the height of the first partition member or the second partition member facing the vent holes of the batteries is not lower than the height capable of accommodating the vent holes of the batteries.
Since other components are the same as those of battery module 400, the description thereof is omitted herein.
According to this exemplary embodiment, even if the temperature of the battery becomes higher due to abnormality and a high-temperature gas is emitted from the vent hole, the gas is exhausted from the air hole formed by the difference between the height of the batteries and the total heights of the first and second partition members, and the first and second partition members can prevent the gas from directly striking the surrounding batteries. As a result, a battery module having excellent reliability and safety can be achieved.
The above-mentioned exemplary embodiment describes an example in which a gap as air hole 550 is formed on the entire periphery of the batteries. However, the configuration is not necessarily limited to this example. For example, the total heights of the walls of the first and second partition members between the neighboring batteries may be about the height of the batteries. Thus, the radiant heat radiated from the side surface of the battery case of a battery with a failure to the neighboring batteries can be considerably reduced.
Hereinafter, a battery module in accordance with a fourth exemplary embodiment of the present invention is described in detail with reference to
As shown in
It is preferable that air holes are provided at positions in which the first partition member and the second partition member are overlapped with each other when the height (depth) of second partition member 625 is in the same level as the height of the battery. However, when the height of the second partition member is lower than that of the battery and when there is a gap in the portion in which the first partition member and the second partition member are overlapped with each other, the gap can be used as an air hole. In this case, an air hole may not be particularly provided in each partition member.
According to this exemplary embodiment, double partitions are provided by the first and second partition members. Therefore, a battery module having more excellent reliability and safety can be achieved.
This exemplary embodiment describes an example of a battery module having a configuration in which a plurality of batteries are connected in parallel. However, the configuration is not necessarily limited to this example. For example, as shown in
Hereinafter, a battery module in accordance with a fifth exemplary embodiment of the present invention is described in detail with reference to
As shown in
In this case, first enclosure 810, second enclosure 820, first partition member 815 and second partition member 825 are formed of the same heat-resistant members as those of first enclosure 110 and first partition member 115 of battery module 100. Note here that other components are the same as those of battery module 100, the description thereof is omitted herein.
According to this exemplary embodiment, even if the temperature of the battery becomes higher due to abnormality and a high-temperature gas is emitted from the vent hole or the explosion-proof valve, the first and second partition members can prevent the high temperature gas from directly striking the surrounding batteries. As a result, it is possible to effectively prevent surrounding batteries from becoming higher in temperature consecutively. Thus, a battery module having safety and reliability can be achieved.
Hereinafter, another example of a battery module in accordance with the fifth exemplary embodiment of the present invention is described with reference to
As shown in
According to the example of this exemplary embodiment, the same effect can be obtained when the battery has a different structure.
Note here that the above-mentioned exemplary embodiment describes an example in which the total heights of the first and second partition members are lower than the height of the battery. However, the configuration is not necessarily limited to this example. For example, the total heights of the first and second partition members may be equal to the height of the battery. At this time, it is preferable that air holes are provided on the side surfaces of the first and second partition members such that the air holes are not provided at positions where the batteries neighbor.
Hereinafter, a battery module in accordance with a sixth exemplary embodiment of the present invention is described in detail with reference to
As shown in
As shown in
According to this exemplary embodiment, when the battery has a different shape, that is, a rectangular shape, if the temperature of the battery becomes higher due to abnormality and a high-temperature gas is emitted from the vent mechanism, the second partition member can prevent the high-temperature gas from directly striking the surrounding batteries. As a result, it is possible to effectively prevent the surrounding batteries from becoming higher in temperature consecutively.
Hereinafter, another example of a battery module in accordance with the sixth exemplary embodiment of the present invention is described with reference to
As shown in
According to the example of this exemplary embodiment, the same effect as mentioned above can be obtained when the battery has a vent mechanism in different positions. Thus, a battery module having excellent safety and reliability can be achieved regardless of the arrangement of batteries.
The above-mentioned example of this exemplary embodiment describes an example in which the total heights of the first and second partition members are not lower than the height of the battery. However, the configuration is not necessarily limited to this example. For example, the total heights of the first and second partition members may be lower than the height of the battery. In this case, it is not particularly necessary to provide an air hole in the first partition member or the second partition member.
Hereinafter, a battery module in accordance with a seventh exemplary embodiment of the present invention is described in detail with reference to
As shown in
According to this exemplary embodiment, high-temperature gas 360, which is emitted from air hole 350 when the temperature of the battery becomes higher due to abnormality, can be exhausted to the outside via exhaust flow passage 1250 as shown by arrow in the drawing. Thus, it is possible to prevent high-temperature gas 360 from directly striking batteries inside the battery module or surrounding batteries of the facing battery modules.
Note here that as shown in
That is to say, a battery module can be configured by arbitrarily connecting unit battery modules in tandem or in parallel so that required voltage and volume can be satisfied.
Note here that in this exemplary embodiment, battery module 300 of the second exemplary embodiment is described as an example of a unit battery module. However, the configuration is not necessarily limited to this example. A battery module may be configured by combining battery modules of the above-mentioned exemplary embodiments as unit battery modules.
Hereinafter, a battery pack in accordance with an eighth exemplary embodiment of the present invention is described in detail with reference to
According to this exemplary embodiment, a battery pack having excellent reliability and safety and having a high versatility can be achieved.
Note here that the first to eighth exemplary embodiments describe examples in which the outer shapes of the first and second enclosures are larger than the outer shapes of the first and second partition members. However, the configuration is not limited to these examples. For example, the outer shape of the first enclosure may be equal to that of the first partition member. The outer shape of the second enclosure may be equal to that of the second partition member. Thus, a smaller and lighter battery module can be achieved.
Furthermore, the configurations specified in each of the exemplary embodiments can be combined with each other.
The present invention is useful in the field of battery modules or battery packs as power sources of, for example, automobiles, bicycles, power tools, and the like, which require high reliability and safety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-052998 | Mar 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/000194 | 1/21/2009 | WO | 00 | 6/11/2010 |
