JP2012234698A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excessive thermal load from being applied on a case when gas exhausted from a storage element directly reaches the case of a power storage device.SOLUTION: A power storage device (1) has a plurality of power storage elements (10) having exhaust ports (12a) for exhausting gas; a connection member (41) contacting electrode terminals (12) of the power storage elements and electrically connecting the plural power storage elements; and a case (20) housing the plural power storage elements and having heat resistance lower than that of the connection member. The connection member is positioned between the exhaust port and the case, and contacts the gas exhausted toward the case from the exhaust port.

Description

  The present invention relates to a power storage device having a plurality of electrically connected power storage elements.

  In the secondary battery, gas may be generated from the inside of the secondary battery due to overcharge or the like. Therefore, a valve is provided in the secondary battery in order to discharge the gas generated inside the secondary battery to the outside of the secondary battery. Specifically, when the internal pressure of the secondary battery reaches the operating pressure of the valve as the gas is generated, the valve changes from the closed state to the open state, thereby discharging the gas to the outside of the secondary battery. Yes.

JP 2009-164085 A JP 2010-192209 A

  In a configuration in which a plurality of secondary batteries are accommodated in the case, there is a possibility that the gas discharged from the secondary battery directly hits the case. Since the gas discharged from the secondary battery is in a high temperature state, there is a possibility that an excessive thermal load is applied to the case.

  A power storage device according to the present invention includes a plurality of power storage elements each having an exhaust port for discharging gas, a connection member that is in contact with an electrode terminal of the power storage element and electrically connects the plurality of power storage elements, and a plurality of power storage devices A case containing the element and having a heat resistance lower than that of the connection member. Here, the connection member is located between the discharge port and the case, and contacts the gas discharged from the discharge port toward the case.

  A part of the connecting member can be positioned on a line extending from the discharge port in the opening direction of the discharge port. Since the gas discharged from the discharge port mainly proceeds in the opening direction of the discharge port, the gas from the discharge port is brought into contact with the connection member by positioning the connection member on a line extending in the opening direction of the discharge port. Can do.

  The connecting member can be made of metal and the case can be made of resin. By bringing the gas into contact with the metal connecting member, the heat of the gas can be easily released to the connecting member, and the temperature of the gas can be easily lowered.

  As the power storage element, a so-called cylindrical power storage element can be used. The cylindrical power storage element extends in a predetermined direction, and a cross section perpendicular to the predetermined direction is formed in a circular shape. Here, the electrode terminals (the positive electrode terminal and the negative electrode terminal) can be provided at both ends in the longitudinal direction of the power storage element. The discharge port can be provided in an electrode terminal (for example, a positive electrode terminal) of the power storage element.

  By using the connection member, a plurality of power storage elements can be electrically connected in parallel. When a cylindrical power storage element is used, a plurality of power storage elements can be arranged side by side in a plane orthogonal to a predetermined direction, and a plurality of positive terminals can be positioned in a plane orthogonal to the predetermined direction. In such an arrangement, a plurality of power storage elements can be electrically connected in parallel by bringing one connection member into contact with the plurality of positive electrode terminals.

  When arranging a plurality of power storage elements in a plane orthogonal to a predetermined direction, a holder for holding the plurality of power storage elements can be used. In addition, the connection member is provided with a plate portion located in a plane orthogonal to the predetermined direction, and a contact portion that is bent so as to protrude toward the electrode terminal with respect to the plate portion and contacts the electrode terminal. be able to.

  When there is a variation in the length of the power storage element in the predetermined direction, the variation in the length of the power storage element can be absorbed by using the bent contact portion. The opening direction of the discharge port can be a direction inclined with respect to the direction in which the power storage element extends (predetermined direction).

  According to the present invention, by using the connection member, it is possible to prevent the gas discharged from the discharge port of the energy storage device from directly reaching the case, and to suppress the thermal load on the case. Can do.

1 is a diagram illustrating an internal structure of a battery block that is Embodiment 1. FIG. In Example 1, it is a figure which shows the arrangement | positioning state of a several cell. It is a front view of the holder in Example 1. In Example 1, it is a figure which shows some internal structures of a cell. In Example 1, it is an enlarged view in the connection part of a connection member and a positive electrode terminal. In Example 1, it is an enlarged view in the connection part of a connection member and a positive electrode terminal. In Example 2, it is a figure which shows the arrangement | positioning state of a several cell.

  Examples of the present invention will be described below.

  A battery block (corresponding to a power storage device) that is Embodiment 1 of the present invention will be described. FIG. 1 is a diagram showing the internal structure of the battery block according to the present embodiment.

  The battery block 1 includes a plurality of unit cells (corresponding to power storage elements) 10 and a case 20 that houses the plurality of unit cells 10. The case 20 has a case main body 21 and a lid 22. The lid 22 is fixed to the upper end of the case body 21 and closes the opening 21 a formed in the case body 21. The case body 21 and the lid 22 can be made of, for example, resin.

  The plurality of single cells 10 accommodated in the case 20 are arranged as shown in FIG. 1 and 2, the X axis, the Y axis, and the Z axis are axes orthogonal to each other. The plurality of single cells 10 can be arranged in an arrangement different from the arrangement shown in FIG. Moreover, the number of the single cells 10 can be selected as appropriate.

  The unit cell 10 is a so-called cylindrical battery. That is, the unit cell 10 extends in the X direction, and the cross-sectional shape of the unit cell 10 in the YZ plane is formed in a circular shape. As the unit cell 10, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor (capacitor) can be used instead of the secondary battery.

  The unit cell 10 includes a battery case 11 and a power generation element accommodated in the battery case 11. The power generation element is an element that performs charge and discharge, and includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. The separator contains an electrolytic solution.

  The positive electrode plate of the power generation element is electrically connected to a positive electrode terminal (corresponding to an electrode terminal) 12 provided at one end of the unit cell 10 in the X direction. The positive terminal 12 has a convex surface. The negative electrode plate of the power generation element is electrically connected to the negative electrode terminal 13 provided at the other end of the unit cell 10 in the X direction. The negative electrode terminal 13 is configured by a flat surface. The positive electrode terminal 12 and the negative electrode terminal 13 constitute a battery case 11.

  The plurality of single cells 10 are held by a holder 30. As shown in FIG. 1, the holder 30 holds the central portion of each unit cell 10 in the X direction. As shown in FIG. 3, the holder 30 has as many openings 31 as the number of unit cells 10. The plurality of unit cells 10 are arranged side by side in the YZ plane. Specifically, a row of five unit cells 10 arranged in the Z direction and a row of four unit cells 10 arranged in the Z direction are alternately arranged in the Y direction.

  In the present embodiment, the holder 30 holds the central portion of the unit cell 10, but can also hold other portions. In addition, a plurality of unit cells 10 can be held using a plurality of holders 30.

  The unit cell 10 is inserted into the opening 31, and a gap formed between the opening 31 and the unit cell 10 is filled with an adhesive. For example, an epoxy resin can be used as the adhesive. The unit cell 10 can be fixed to the holder 30 by filling the gap formed between the opening 31 and the unit cell 10 with an adhesive.

  The holder 30 can be formed of a metal such as aluminum, for example. By forming the holder 30 with a metal, the heat dissipation of the unit cell 10 can be improved. The unit cell 10 may generate heat due to charging / discharging or the like. If the holder 30 is made of metal, the heat generated in the unit cell 10 can be easily released to the holder 30, and the temperature increase of the unit cell 10 can be suppressed.

  The holder 30 is fixed to the case 20. As a structure for fixing the holder 30 to the case 20, a known structure can be used as appropriate. For example, the holder 30 can be fixed to the case 20 using a bolt.

  The positive terminals 12 in the plurality of unit cells 10 are located on the same side with respect to the holder 30 and are connected to the connection member 41. The connection member 41 is made of a conductive material such as metal. The connection member 41 has a contact portion 41a that comes into contact with the positive electrode terminal 12, and the contact portions 41a are provided as many as the number of the unit cells 10 (positive electrode terminals 12). The contact portion 41a is bent and protrudes toward the positive electrode terminal 12. The contact part 41a and the positive electrode terminal 12 are welded.

  The connection member 41 has a lead portion 41 b, and the lead portion 41 b passes through an opening 22 a formed in the lid 22 and protrudes outside the case 20. The positive terminal 51 of the battery block 1 is fixed to the lead part 41b.

  The negative terminals 13 in the plurality of unit cells 10 are located on the same side with respect to the holder 30 and are connected to the connection member 42. The connection member 42 is made of a conductive material such as metal. The connection member 42 has a structure similar to that of the connection member 41, and has a contact portion 42 a that contacts the negative electrode terminal 13. The contact part 42a is provided by the number of the unit cells 10 (negative electrode terminals 13), and is welded to the negative electrode terminal 13.

  Further, the connecting member 42 has a lead portion 42 b, and the lead portion 42 b passes through the opening 22 b formed in the lid 22 and protrudes outside the case 20. The negative terminal 52 of the battery block 1 is fixed to the lead part 42b.

  By connecting one connecting member 41 to the plurality of positive terminals 12 and connecting one connecting member 42 to the plurality of negative terminals 13, the plurality of single cells 10 are electrically connected in parallel. can do.

  In the present embodiment, the contact portion 41a and the positive electrode terminal 12 can be easily connected by bending the contact portion 41a. Here, when there is a variation in the length of the unit cell 10 in the X direction due to a manufacturing error of the unit cell 10, the contact portion 41 a is elastically deformed to absorb the variation in the length of the unit cell 10. be able to. By bending the contact portion 42a of the connection member 42, the contact portion 42a and the negative electrode terminal 13 can be easily connected.

  In this embodiment, the connection members 41 and 42 have the same structure, but the present invention is not limited to this. Since the connection member 42 is connected to the negative electrode terminal 13 configured with a flat surface, the contact portion 42a need not be bent. In other words, the connecting member 42 formed in a flat plate shape may be simply connected to the plurality of negative electrode terminals 13.

  The battery block 1 can be mounted on a vehicle and used as a power source for running the vehicle. Specifically, a battery pack can be configured by electrically connecting a plurality of battery blocks 1 in series, and the battery pack can be mounted on a vehicle. In each battery block 1, since the plurality of single cells 10 are electrically connected in parallel, the capacity of the battery block 1 is increased as compared with the case where the plurality of single cells 10 are electrically connected in series. Can do. Therefore, the travel distance of the vehicle using the output of the battery block 1 can be extended.

  When the unit cell 10 is overcharged, gas may be generated mainly from the power generation element. Since the inside of the battery case 11 is hermetically sealed, when gas is generated from the power generation element, the internal pressure of the battery case 11 increases. Here, in order to suppress the internal pressure of the battery case 11 from increasing, the cell 10 is provided with a valve.

  When the internal pressure of the battery case 11 reaches the operating pressure of the valve, the valve changes from the closed state to the open state, thereby discharging the gas present in the battery case 11 to the outside of the battery case 11. A structure for discharging gas will be described with reference to FIG. FIG. 4 is a diagram showing an internal structure in a part of the unit cell 10.

  The valve plate 14 is sandwiched between the positive electrode terminal 12 and the sealing plate 15. The outer edge of the sealing plate 15 sandwiches the outer edge of the positive electrode terminal 12 and the outer edge of the valve plate 14. The sealing plate 15 is provided to close the opening of the battery case 11, and a gasket 16 is disposed between the sealing plate 15 and the battery case 11. Thereby, the inside of the cell 10 will be in a sealed state.

  The gasket 16 is made of an insulating material such as resin, and the positive electrode terminal 12 and the battery case 11 are in an insulated state. The battery case 11 is used as the negative electrode terminal 13. The sealing plate 15 has a gas passage 15 a that penetrates the sealing plate 15, and the positive electrode terminal 12 has a discharge port 12 a that penetrates the positive electrode terminal 12.

  When gas is generated from the power generation element, the gas passes through the gas passage 15 a and enters the space S <b> 1 formed between the sealing plate 15 and the valve plate 14. When the internal pressure of the unit cell 10 reaches the operating pressure of the valve plate 14, the valve plate 14 is broken and the gas moves to the space S <b> 2 formed between the positive electrode terminal 12 and the valve plate 14. The gas that has moved to the space S <b> 2 passes through the discharge port 12 a formed in the positive electrode terminal 12 and is discharged to the outside of the unit cell 10.

  In this embodiment, the gas discharged from the discharge port 12a hits the connecting member 41. This structure will be described with reference to FIGS. FIG. 5 is an enlarged view of the positive terminal 12 and the connecting member 41 of the unit cell 10 as viewed from the Y direction, and FIG. 6 is a view of the positive terminal 12 and the connecting member 41 of the unit cell 10 from the X direction. FIG.

  5 and FIG. 6, an arrow indicated by a dotted line indicates a main moving direction of the gas discharged from the discharge port 12 a of the unit cell 10. As shown in FIG. 6, the positive electrode terminal 12 has three discharge ports 12a, and gas is discharged from each discharge port 12a. The gas discharged from the discharge port 12 a hits the plate portion 41 b of the connection member 41.

  In the present embodiment, the three outlets 12a are formed in the positive terminal 12, but the present invention is not limited to this. That is, it is only necessary that gas can be discharged from the space S2 (see FIG. 4) to the outside of the unit cell 10, and the number of the discharge ports 12a and the positions where the discharge ports 12a are formed can be set as appropriate. In this embodiment, the gas discharged from the discharge port 12a is abutted against the plate portion 41b. However, the gas may be abutted against the contact portion 41a.

  The plate portion 41b is formed in a flat plate shape and is disposed along the YZ plane. The contact portion 41a protrudes in the X direction with respect to the plate portion 41b, and a cutout portion 41c is formed around the contact portion 41a.

  In this embodiment, the notch 41c is formed in the shape shown in FIG. 6, but the present invention is not limited to this. That is, the gas discharged from the discharge port 12a may hit the connection member 41 without directly passing through the notch 41c. Specifically, it is only necessary that a part of the connection member 41 is located on the movement locus of the gas discharged from the discharge port 12a. The gas movement trajectory here is the main movement trajectory of the gas discharged from the discharge port 12a, and is determined according to the direction of the discharge port 12a. That is, the gas movement locus extends from the discharge port 12a in the opening direction of the discharge port 12a.

  In the present embodiment, the contact portion 41a protrudes toward the positive electrode terminal 12 with respect to the plate portion 41b, but the present invention is not limited to this. For example, the connection member 41 may be configured as a single plate and only contacted with the plurality of positive electrode terminals 12.

  Here, when connecting the connection member 41 and the positive electrode terminal 12 by welding, it is preferable to form a notch in the region of the connection member 41 facing the positive electrode terminal 12. Thereby, the electrode for welding can be arrange | positioned in two area | regions which pinch | interpose a notch part, and the connection member 41 and the positive electrode terminal 12 can be welded easily. Even when the connection member 41 having only the notch is used, the gas discharged from the discharge port 12a may be made to abut against a part of the connection member 41.

  According to the present embodiment, the gas discharged from the unit cell 10 (discharge port 12a) is abutted against the connecting member 41 so that the gas does not directly abut against the case 20. Since the gas is discharged from the unit cell 10 in a high temperature state, if the gas hits the case 20, the case 20 receives a thermal load. In particular, when the case 20 is made of resin, the influence of the thermal load increases. The material for forming the case 20 is not limited to resin, and can be formed of a material having lower heat resistance than the connection member 41.

  In the present embodiment, by causing the gas to abut against the connection member 41, it is difficult for the thermal load due to the gas to act on the case 20. Here, since the connection member 41 is made of metal and has higher heat resistance than the case 20, the gas can abut against the connection member 41. By abutting the gas against the connecting member 41, the heat of the gas can be released to the connecting member 41, and the temperature of the gas after coming into contact with the connecting member 41 can be lowered. If the temperature of the gas is lowered, the thermal load that the gas gives to the case 20 can be reduced.

  In the present embodiment, the connecting member 41 is not only provided with a function of electrically connecting the plurality of positive terminals 12 but also provided with a function of preventing the gas from striking the case 20. Thus, by providing the connecting member 41 with two functions, the number of parts can be reduced.

  As a means for lowering the gas temperature, it is conceivable to secure a sufficient distance between the outlet 12a and the case 20. That is, as the case 20 is separated from the discharge port 12a, the moving distance of the gas reaching the case 20 from the discharge port 12a becomes longer, and the gas temperature can be lowered. However, the case 20 (battery block 1) becomes larger as the case 20 is separated from the discharge port 12a.

  In this embodiment, it is not necessary to separate the case 20 from the discharge port 12a, and the case 20 can be brought close to the discharge port 12a. Thereby, the enlargement of case 20 (battery block 1) can be suppressed.

  In the present embodiment, the gas discharged from the cell 10 is accumulated inside the battery block 1 (case 20). Therefore, a valve is provided in the case 20 so that the gas accumulated inside the case 20 can be discharged to the outside of the case 20. As the valve provided in the case 20, a so-called destructive valve or a so-called return valve can be used. A destructive valve is a valve that changes irreversibly from a closed state to an open state. The return type valve is a valve that reversibly changes between a closed state and an open state in accordance with the internal pressure of the case 20.

  A battery block that is Embodiment 2 of the present invention will be described. In the present embodiment, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 7 is an external view showing the configuration of the plurality of unit cells 10 accommodated in the case 20. The conductive wire 61 is in contact with the plurality of positive terminals 12 and is fixed to the holding plate 62. The conductive wire 61 can be fixed to the holding plate 62 by using, for example, an adhesive. The conductive wire 61 and the holding plate 62 in this embodiment correspond to the connection member of the present invention.

  One end of the conductive wire 61 is connected to the positive terminal 51 (see FIG. 1) of the battery block 1. The conductive wire 61 is formed of a conductive material such as metal. The holding plate 62 is formed of a material having higher heat resistance than the case 20. For example, the holding plate 62 can be formed of a metal or a thermosetting resin.

  The negative terminals 13 in the plurality of unit cells 10 can also be electrically connected using the conductive wires 61. In addition, the conductive wires 61 connected to the plurality of negative terminals 13 can be fixed to the holding plate 62. One end of the conductive wire 61 connected to the negative terminal 13 is connected to the negative terminal 52 (see FIG. 1) of the battery block 1.

  According to the present embodiment, the gas discharged from the single cell 10 (discharge port 12a) hits the holding plate 62. Thereby, it is possible to prevent the gas discharged from the unit cell 10 from directly hitting the case 20.

1: Battery block (power storage device) 10: Single battery (power storage element)
11: Battery case 12: Positive terminal (electrode terminal)
12a: Discharge port 13: Negative electrode terminal 14: Valve plate 15: Sealing plate 15a: Gas passage 16: Gasket 20: Case 21: Case body 22: Lid 30: Holder 31: Opening portion 41, 42: Connection members 41a, 42a: Contact part 51: Positive terminal 52: Negative terminal 61: Conductive wire 62: Holding plate

Claims (9)

A plurality of power storage elements each having a discharge port for discharging gas;
A connecting member that is in contact with the electrode terminal of the power storage element and electrically connects the plurality of power storage elements;
Housing the plurality of power storage elements, and having a heat resistance lower than that of the connection member,
The power storage device, wherein the connection member is located between the discharge port and the case and contacts a gas discharged from the discharge port toward the case.   2. The power storage device according to claim 1, wherein a part of the connection member is located on a line extending from the discharge port in an opening direction of the discharge port.   The power storage device according to claim 1, wherein the connection member electrically connects the plurality of power storage elements in parallel. The connecting member is made of metal,
The power storage device according to any one of claims 1 to 3, wherein the case is made of a resin. The power storage element extends in a predetermined direction, and a cross section perpendicular to the predetermined direction is formed in a circle,
5. The power storage device according to claim 1, wherein the electrode terminals are provided at both ends in the longitudinal direction of the power storage element.   The power storage device according to claim 5, wherein the discharge port is provided in the electrode terminal located at one end in the longitudinal direction of the power storage element.   The power storage device according to claim 6, wherein an opening direction of the discharge port is a direction inclined with respect to the predetermined direction.   8. The holder according to claim 5, further comprising a holder that holds the plurality of power storage elements in a state where the plurality of power storage elements are arranged in a plane orthogonal to the predetermined direction. Power storage device. The connecting member is
A plate portion located in a plane orthogonal to the predetermined direction;
A bending portion that protrudes toward the electrode terminal with respect to the plate portion, and a contact portion that contacts the electrode terminal;
The power storage device according to claim 8, further comprising:

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