Battery pack with structure to prevent intrusion of charged particles

Abstract

To provide a battery pack which prevents conductive foreign objects from entering a case.SOLUTION: A battery pack according to the disclosure includes: a battery cell; a case which houses the battery cell; a smoke exhaust port provided at the case; and a trap device which is provided at the outer side of the smoke exhaust port and forms an electric field or a magnetic field at the outer side of the smoke exhaust port to trap charged particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack. [Background technology]

[0002] The battery pack disclosed in Patent Document 1 has a magnet placed inside the case that houses the battery cells. The magnet attracts magnetic materials such as iron powder, reducing the risk of short circuits between battery cells caused by iron powder, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-047373 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery pack disclosed in Patent Document 1, it is difficult to prevent the intrusion of non-magnetic conductive foreign matter. Furthermore, because a magnet is placed inside the case, there is a risk that a large amount of foreign matter may enter the case, making it impossible to completely avoid the risk of short-circuiting between battery cells.

[0005] The present disclosure provides a battery pack that can prevent conductive foreign matter from entering the inside of a case that houses battery cells. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a battery pack comprising: a battery cell, a case for accommodating the battery cell, a smoke exhaust port provided in the case, and a trapping device provided outside the smoke exhaust port for trapping charged particles by forming an electric or magnetic field outside the smoke exhaust port. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to prevent conductive foreign matter from entering the case, thereby reducing the risk of short circuits occurring in the battery cells. [Brief explanation of the drawings]

[0008] [Figure 1] 1 shows a first embodiment of the present disclosure. [Figure 2] 2 shows a second embodiment of the present disclosure. [Figure 3] 3 shows a third embodiment of the present disclosure. [Figure 4] 10 shows a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Figure 1 shows a battery pack 1 according to a first embodiment of the present disclosure. The battery pack 1 is intended for use as a power source for electric vehicles, and is particularly suitable for electric vehicles that will travel on the surface of the moon. The battery pack 1 shown in Figure 1(A) is composed of a battery cell 2, a case 3, a trap device 5, and an insulating connector 9.

[0010] The battery cell 2 is a secondary battery in which unit cells 21 are connected in series. The unit cells 21 are, for example, lithium-ion secondary batteries. The battery cell 2 is housed inside the case 3. Conductors are connected to each terminal of the battery cell 2, and the battery cell 2 is electrically connected to an external circuit. Specifically, the positive and negative terminals of the battery cell 2 are each connected to an external circuit outside the case 3 by conductors. The conductors connecting the battery cell 2 to the external circuit are equipped with an insulating connector 9 at the portion leading out of the case 3 so as not to interfere with the case 3. More specifically, the conductors pass through the inside of the insulating connector 9, electrically connecting the battery cell 2 inside the case 3 to the external circuit outside the case 3 without electrically interfering with the case 3.

[0011] In the first embodiment, the case 3 is electrically connected to the negative terminal of the battery cell 2 via a conductor. The conductor connecting the case 3 to the negative terminal of the battery cell 2 is a separate conductor from the conductor drawn from the negative terminal of the battery cell 2 to the outside of the case 3.

[0012] The case 3 has a smoke exhaust vent 4 on the side of the case 3. The smoke exhaust vent 4 is provided to allow smoke to escape to the outside of the case 3 when a malfunction occurs in a battery cell 2 inside the case 3 and smoke is emitted.

[0013] The trap device 5 includes a canopy 7 provided on the outside of the smoke exhaust port 4, and a plate 6 extending from inside the case 3 through the smoke exhaust port 4 to the outside of the smoke exhaust port 4. The plate 6 and the canopy 7 face each other vertically, and the plate 6 is positioned vertically below the canopy 7. The canopy 7 is integrated with the case 3 or is electrically connected to the case 3, and is therefore electrically connected to the negative terminal of the battery cell 2 through the case 3. The plate 6 is a lattice plate with many holes. However, the plate 6 is not limited to a lattice-shaped plate, and may be a plate with many circular holes, such as perforated metal. The plate 6 is electrically connected to the positive terminal of the battery cell 2 inside the case 3.

[0014] In this embodiment, the plate 6 corresponds to the first electrode, and the canopy 7 corresponds to the second electrode. The plate 6 as the first electrode is electrically connected to the + terminal of the battery cell 2, and the canopy 7 as the second electrode is electrically connected to the - terminal of the battery cell 2 via the case 3. In other words, the plate 6 as the first electrode is a positive electrode, and the canopy 7 as the second electrode is a negative electrode. Hereinafter, the plate 6 as the first electrode will be referred to as the positive electrode 6, and the canopy 7 as the second electrode will be referred to as the negative electrode 7.

[0015] 1(B) shows how the trap device 5 in the first embodiment prevents foreign objects 8 from entering the case 3. The foreign objects 8 assumed here are, for example, conductive dust particles present on the surface of the moon. The foreign objects 8 include negatively charged foreign objects 81 and positively charged foreign objects 82.

[0016] The positive electrode 6 attracts the negatively charged foreign object 81, and by transferring negative charges (electrons) to and from the foreign object 81, the negatively charged foreign object 81 is electrically neutralized. On the other hand, the negative electrode 7 attracts the positively charged foreign object 82 and transfers negative charges (electrons) to the positively charged foreign object 82 to electrically neutralize the foreign object 82. The attracted foreign objects 81 and 82 become electrically neutral at the positive electrode 6 or the negative electrode 7 respectively, and are in an uncharged state, so they fall vertically downward due to gravity. In this embodiment, the direction from the negative electrode 7 to the positive electrode 6 is vertically downward, and the foreign object 8 falls in the direction from the negative electrode 7 to the positive electrode 6.

[0017] In the positive electrode 6 shown in FIG. 1(B), an electrode entity part where there is no hole and there is an electrode in reality is denoted as a. Also, if the electrode distance between the positive electrode 6 and the negative electrode 7 is denoted as b, it is preferable that the relationship a < b holds. According to this relationship, it is possible to effectively suppress the foreign object 8 accumulated on the positive electrode 6 from reaching the negative electrode 7.

[0018] Regarding the maximum diameter c of the hole, it is required to be at least larger than the maximum diameter of the foreign object 8. Since the maximum diameter of the foreign object 8 varies depending on the usage environment of the battery pack 1, the maximum diameter c of the hole of the positive electrode 6 may be changed according to the usage environment of the battery pack 1.

[0019] According to the battery pack 1 disclosed in this embodiment, it is possible to prevent the foreign object 8 from entering the inside of the case 3 from the smoke exhaust port 4 due to the vertical electric field formed by the positive electrode 6 and the negative electrode 7 constituting the trap device 5.

[0020] FIG. 2 shows a second embodiment in the present disclosure.

[0021] The battery pack 1 shown in FIG. 2(A) is composed of a battery cell 2, a case 3, a trap device 5, and an insulating connector 9. Also, similar to the first embodiment, the battery pack 1 is used for an electric vehicle traveling on the lunar surface. The configurations of the battery cell 2, the case 3, the smoke exhaust port 4, and the insulating connector 9 in this embodiment are the same as those in the first embodiment, and the description thereof is omitted here.

[0022] The trap device 5 in this embodiment is installed outside the smoke exhaust port 4 to generate a horizontal electric field. Specifically, the trap device 5 includes a lid 71 installed on the smoke exhaust port 4 and two plates 6 and 72 disposed in front of the lid and hanging down vertically. The lid 71 and plate 6 face each other horizontally, and the plates 6 and 72 also face each other horizontally. The lid 71 is a lattice plate with many holes. However, the lid 71 is not limited to a lattice-shaped plate and may be a plate with many circular holes, such as perforated metal. The lid 71 is integrated with the case 3 or electrically connected to the case 3, and is electrically connected to the negative terminal of the battery cell 2 via the case 3. The plates 6 and 72 are also lattice plates with many holes. The plates 6 and 72 are also not limited to a lattice-shaped plate and may be a plate with many circular holes, such as perforated metal. The plate 6 is electrically connected to the positive terminal of the battery cell 2 by a conductor extending from inside the case 3. Plate 72 is electrically connected to lid 71 by bridges 73 .

[0023] In this embodiment, the plate 6 corresponds to the first electrode, the lid 71 corresponds to the second electrode, and the plate 72 corresponds to the third electrode. The plate 6 as the first electrode is electrically connected to the + terminal of the battery cell 2 via a conductor. The lid 71 as the second electrode is electrically connected to the - terminal of the battery cell 2 via the case 3. The plate 72 as the third electrode is electrically connected to the - terminal of the battery cell 2 via a bridge 73 and the case 3. In other words, the plate 6 as the first electrode is a positive electrode, and the lid 71 as the second electrode and the plate 72 as the third electrode are negative electrodes. Hereinafter, the plate 6 as the first electrode will be referred to as the positive electrode 6, and the lid 71 as the second electrode and the plate 72 as the third electrode will be referred to as the negative electrodes 71 and 72.

[0024] In trap device 5, positive electrode 6 is arranged so that the surface facing the side surface of case 3 faces negative electrode 71, and the other surface faces negative electrode 72. In other words, positive electrode 6 is arranged in an opposing region where negative electrode 71 faces negative electrode 72. By arranging positive electrode 6, negative electrode 71, and negative electrode 72 in this manner, trap device 5 generates an electric field in the horizontal direction.

[0025] Figure 2(B) shows how the trap device 5 in the second embodiment prevents foreign matter 8 from entering the case 3. The foreign matter 8 has conductivity as in the first embodiment, and includes negatively charged foreign matter 81 and positively charged foreign matter 82.

[0026] The positive electrode 6 attracts the negatively charged foreign matter 81, and electrically neutralizes the negatively charged foreign matter 81 by exchanging negative charges (electrons) with the foreign matter 81. The negative electrodes 71 and 72 attract the positively charged foreign matter 82, and electrically neutralize the foreign matter 82 by passing negative charges (electrons) to the positively charged foreign matter 82. Therefore, the foreign matter 8 becomes electrically neutral and uncharged, and thus falls vertically downward due to gravity.

[0027] Also, when the electrode distance between the positive electrode 6 and the negative electrode 71 is d, and the electrode distance between the positive electrode 6 and the negative electrode 72 is e, it is preferable that the positive electrode 6, the negative electrode 71, and the negative electrode 72 are arranged such that the relationship d < e holds between the electrode distances d and e. In this case, when d < e is satisfied, the electric field E1 formed in the region where the positive electrode 6 and the negative electrode 71 face each other becomes stronger than the electric field E2 formed in the region where the positive electrode 6 and the negative electrode 72 face each other. That is, the magnitude of the force attracting each electrode to the foreign matter 8 is also greater for the electric field E1 than for the electric field E2.

[0028] For example, when the negatively charged foreign matter 81 approaches the positive electrode 6 from the side of the electric field E2, passes through the positive electrode 6, and enters the electric field E1 (hereinafter, this event is described as an overrun), the magnitude of the force in the direction of the positive electrode 6 applied to the foreign matter 81 in the electric field E1 is greater than the magnitude of the force in the direction of the positive electrode 6 applied to the foreign matter 81 in the electric field E2. Therefore, the foreign matter 81 is pushed back to the side of the electric field E2. Thus, even when the foreign matter 81 overruns from the electric field E2 toward the electric field E1, it is difficult for the foreign matter 81 to enter the case 3.

[0029] According to the battery pack 1 disclosed in the present embodiment, the horizontal electric fields formed by the positive electrode 6 and the negative electrode 71 and the positive electrode 6 and the negative electrode 72 that constitute the trap device 5 prevent foreign matter 8 from entering the inside of the case 3.

[0030] FIG. 3 shows a third embodiment of the present disclosure.

[0031] In this embodiment, the battery pack 1 is composed of a battery cell 2, a case 3, a trap device 5, and an insulating connector 9. As in the first embodiment, the battery pack 1 is used in an electric vehicle that runs on the surface of the moon. The battery cell 2 is housed inside the case 3, and each terminal is electrically connected to an external circuit. The configuration of the conductors connecting the battery cell 2 to the external circuit and the insulating connector 9 is the same as in the first embodiment, so a description thereof will be omitted here.

[0032] In this embodiment, the trap device 5 comprises a lid 6 provided on the smoke exhaust port and a plate 7 disposed in front of the lid and hanging down vertically. The lid 6 and the plate 7 face each other horizontally. The lid 6 is a lattice plate with many holes. However, the lid 6 is not limited to a lattice-like one, and may be a plate with many circular holes, such as perforated metal. The lid 6 is integrated with the case 3 or is electrically connected to the case 3. The plate 7 is a lattice plate with many holes. The plate 7 is also not limited to a lattice-like one, and may be a plate with many circular holes, such as perforated metal.

[0033] Furthermore, both terminals of the battery cell 2 are electrically connected to the case 3 by conductors inside the case 3. Specifically, the conductor connected to the negative terminal of the battery cell 2 is connected to a switch 10, and the switch 10 is connected to the case 3 by a conductor. The conductor connected to the positive terminal of the battery cell 2 is connected to a switch 11, and the switch 11 is connected to the case 3 by a conductor. In other words, the negative and positive terminals of the battery cell 2 can be electrically connected to or isolated from the case 3 by operating the switches 10 and 11, respectively.

[0034] The conductor connecting the negative terminal of battery cell 2 to the external circuit is further connected to another conductor, which is connected to switch 12. Switch 12 is electrically connected to plate 7. Furthermore, the conductor connecting the positive terminal of battery cell 2 to the external circuit is further connected to another conductor, which is connected to switch 13. Switch 13 is electrically connected to plate 7. The negative and positive terminals of battery cell 2 can be electrically connected to or isolated from plate 7 by operating switches 12 and 13, respectively.

[0035] In this embodiment, the lid 6 corresponds to the first electrode, and the plate 7 corresponds to the second electrode. The plate 6 as the first electrode is electrically connected to the + terminal of the battery cell 2 via a conductor. The lid 71 as the second electrode is electrically connected to the - terminal of the battery cell 2 via the case 3. The plate 72 as the third electrode is electrically connected to the - terminal of the battery cell 2 via a bridge 73 and the case 3. In other words, the plate 6 as the first electrode is a positive electrode, and the lid 71 as the second electrode and the plate 72 as the third electrode are negative electrodes. Hereinafter, the plate 6 as the first electrode will be referred to as the positive electrode 6, and the lid 71 as the second electrode and the plate 72 as the third electrode will be referred to as the negative electrodes 71, 72.

[0036] In this embodiment, the lid 6 corresponds to the first electrode, and the plate 7 corresponds to the second electrode. The electrical characteristics of the lid 6 as the first electrode and the plate 7 as the second electrode can be switched by operating switches 10 to 13. For example, when switches 10 and 13 are turned ON and switches 11 and 12 are turned OFF, the lid 6 as the first electrode connected to the case 3 is connected to the negative electrode of the battery cell 2 and is therefore negatively charged, and the plate 7 as the second electrode provided outside the case 3 is connected to the positive electrode of the battery cell 2 and is therefore positively charged. In this case, the lid 6 as the first electrode serves as the negative electrode, and the plate 7 as the second electrode serves as the positive electrode, constituting the trap device 5.

[0037] The battery pack 1 disclosed in this embodiment can apply an appropriate electric field depending on the surrounding environment of the battery pack 1. For example, on the surface of the moon, where the battery pack 1 is expected to be used, foreign matter 8 contained in sand and dust will be charged to different polarities depending on whether the moon is exposed to the sun. When the moon is exposed to the sun, foreign matter 8 on the lunar surface becomes positively charged foreign matter 82, and when the moon is not exposed to the sun, foreign matter 8 becomes negatively charged foreign matter 81. Therefore, when the moon is exposed to the sun, the cover 6 as the first electrode acts as a positive electrode and the plate 7 as the second electrode acts as a negative electrode, thereby efficiently preventing the intrusion of foreign matter 8. When the moon is not exposed to the sun, the cover 6 as the first electrode acts as a negative electrode and the plate 7 as the second electrode acts as a positive electrode, thereby efficiently preventing the intrusion of foreign matter 8. This switching of the potentials of the electrodes may be performed using a relay circuit.

[0038] According to the battery pack 1 disclosed in this embodiment, when the polarity of the charged particles contained in the foreign matter 8 is biased, the foreign matter 8 can be efficiently prevented from entering the case 3.

[0039] Fig. 4 shows a fourth embodiment of the present disclosure. First, Fig. 4(A) shows a schematic diagram of a battery pack 1 in this embodiment.

[0040] In this embodiment, the battery pack 1 is made up of a battery cell 2, a case 3, a trap device 14, and an insulating connector 9. As in the first embodiment, the battery pack 1 is used in an electric vehicle that runs on the surface of the moon.

[0041] The battery cells 2 arranged inside the case 3 are electrically connected to an external circuit outside the case 3 by conductors connecting the + and - terminals, respectively. That is, the + and - terminals of the battery cells 2 are drawn to the outside of the case 3 by conductors. The conductors are insulated from the case 3 by an insulating connector 9. Specifically, the conductors pass through the inside of the insulating connector 9 and are drawn from the inside of the case 3 to the outside, thereby isolating the conductors from the case 3. The battery cells 2 are also insulated from the case 3 inside the case 3.

[0042] The case 3 has a smoke exhaust port 4 on its side. The trap device 14 is provided outside the smoke exhaust port 4 so as to generate a magnetic field in the vertical direction. Specifically, the trap device 14 is composed of an upper magnetic body 31, a lower magnetic body 32, a magnet 15, and a magnet 16.

[0043] The upper magnetic body 31 is disposed above the smoke exhaust port 4, and the lower magnetic body 32 is disposed below the smoke exhaust port 4. Both side surfaces between the upper magnetic body 31 and the lower magnetic body 32 are covered with, for example, a non-magnetic member. Openings 41 are provided at the tips of the upper magnetic body 31 and the lower magnetic body 32.

[0044] Magnet 15 is attached to upper magnetic body 31, and magnet 16 is attached to lower magnetic body 32. Magnets 15 and 16 face each other in the vertical direction, and the magnetism of the surface of magnet 15 facing magnet 16 is different from the magnetism of the surface of magnet 16 facing magnet 15.

[0045] FIG. 4B shows a schematic diagram of the magnetic field H formed in the opening 41.

[0046] The magnetic circuit formed by the upper magnetic body 31 and magnet 15 and the lower magnetic body 32 and magnet 16 creates a magnetic field H that extends vertically and increases the magnetic flux density at the opening 41. Any foreign object 8 carrying an electric charge that attempts to enter the case 3 through the opening 41 undergoes a rotational motion, rotating around the magnetic field lines that make up the magnetic field H and moving in the direction of the magnetic field lines. As a result, the foreign object 8 is either repelled to the outside of the magnetic bodies 31 and 32 at the opening 41, or is caught by the magnetic field lines and loses its horizontal velocity, causing it to fall. This prevents the foreign object 8 from entering the case 3. [Explanation of symbols]

[0047] 1 battery pack, 2 battery cell, 3 case, 4 smoke exhaust port, 5, 14 trap device, 6 positive electrode, 7 negative electrode, 8 foreign object, 9 insulating connector, 10-13 switch, 15, 16 magnet

Claims

1. A battery cell; a case for housing the battery cell; A smoke exhaust port provided in the case; a trapping device provided outside the smoke exhaust port for trapping charged particles by forming an electric field or a magnetic field outside the smoke exhaust port; The trapping device is a first electrode; a second electrode disposed opposite the first electrode and having a different potential from the first electrode; The smoke exhaust port is provided on a side surface of the case, A canopy is provided on the outside of the smoke exhaust port, A plate with a number of holes extending from the inside of the case to the outside of the smoke exhaust port is provided inside the smoke exhaust port, the plate is electrically connected to one terminal of the battery cell to form the first electrode; the canopy is electrically connected to the other terminal of the battery cell to form the second electrode; A vertical electric field is formed between the first electrode and the second electrode. A battery pack characterized by:

2. A battery cell; a case for housing the battery cell; A smoke exhaust port provided in the case; a trapping device provided outside the smoke exhaust port, which traps charged particles by forming an electric field or a magnetic field outside the smoke exhaust port; The trapping device is a first electrode; a second electrode disposed opposite the first electrode and having a different potential from the first electrode; The smoke exhaust port is provided on a side surface of the case, The smoke exhaust port is provided with a cover having a number of holes therein, A plate with many holes is disposed in front of the lid and hangs down vertically, the plate is electrically connected to one terminal of the battery cell to form the first electrode; the lid is electrically connected to the other terminal of the battery cell to form the second electrode; A horizontal electric field is formed between the first electrode and the second electrode. Battery pack.

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