JP2019175552A - Secondary battery module and secondary battery pack - Google Patents

Abstract

To provide a secondary battery module and a secondary battery pack that can suppress fluctuations in output performance and can be reduced in size and weight.SOLUTION: A secondary battery module 20 including a secondary battery cell 30 having an electrode body in which a positive electrode and a negative electrode are laminated via a separator, and a battery exterior member (case) that houses the electrode body together with a non-aqueous electrolyte includes a decompression mechanism 200 that depressurizes the inside of the secondary battery cell 30.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a secondary battery module and a secondary battery pack that are mounted on a vehicle such as an automobile and that include a secondary battery cell in which an electrode body and a nonaqueous electrolyte are housed in a battery exterior member (case).

  Conventionally, for example, as a secondary battery (secondary battery module or secondary battery pack) for a relatively small electronic device such as a mobile phone or a personal computer, a nickel metal hydride secondary battery or a lithium ion secondary battery is representative. Nonaqueous electrolyte secondary batteries and the like are known. In recent years, development of large-sized secondary batteries mounted on various vehicles such as electric vehicles has been progressing.

  As a structure of the secondary battery cell provided in such a secondary battery, for example, an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator is housed in a battery exterior member (case) together with a non-aqueous electrolyte. Some battery exterior members (cases) are sealed with a lid (sealing) member. In recent years, a so-called all-solid battery in which the secondary battery is solidified by replacing the non-aqueous electrolyte with a solid electrolyte layer has been developed.

  By the way, in the secondary battery cell of such a structure, the output performance of the secondary battery cell fluctuates due to the volume change at the time of charge and discharge and the influence of increase / decrease in the distance between the positive electrode and the negative electrode due to gas generation, There is a possibility that problems such as a shortened life may occur.

  In order to solve such a problem, there is a battery in which a secondary battery cell constituting a secondary battery is restrained to suppress an increase or decrease in the distance between the positive electrode and the negative electrode. For example, there is one in which a single or a plurality of secondary battery cells are constrained by a predetermined restraining jig and an arbitrary restraining pressure is applied to the plane of the secondary battery cell (see Patent Document 1).

International Publication No. 2013/121563

  Thus, by restraining the secondary battery cell by the restraining jig, the expansion of the secondary battery cell can be suppressed. Therefore, increase / decrease in the distance between the positive electrode and the negative electrode accommodated in the inside is suppressed, and the occurrence of problems such as fluctuations in the output performance of the secondary battery cell can be suppressed.

  However, when the secondary battery cell is restrained by the restraining jig, there is a problem that the secondary battery module and the secondary battery pack are increased in size and weight. For example, since a secondary battery module and a secondary battery pack for a vehicle include a large number of secondary battery cells, if all the secondary battery cells are to be restrained by a restraining jig, the restraining jig is enlarged. The necessity arises, and accordingly, the secondary battery pack is increased in size and weight.

  The present invention has been made in view of such circumstances, and provides a secondary battery module and a secondary battery pack that can suppress fluctuations in output performance and can be reduced in size and weight. For the purpose.

  One aspect of the present invention that solves the above problems includes an electrode body in which a positive electrode and a negative electrode are laminated via a separator, and a battery exterior member (case) that houses the electrode body together with a nonaqueous electrolyte. A secondary battery module including a secondary battery cell, wherein the secondary battery module includes a decompression mechanism that decompresses the inside of the battery exterior member (case) of the secondary battery cell.

  Here, the decompression mechanism includes: an exhaust passage member connected to the battery exterior member (case); and a vacuum pump provided in the exhaust passage member to exhaust and decompress the interior of the battery exterior member (case). It is preferable to include.

  Furthermore, when the secondary battery module includes a plurality of the secondary battery cells, the exhaust passage member includes an individual passage portion connected to the battery exterior member (case) of each secondary battery cell, and each individual It is preferable that the vacuum pump is disposed downstream of the connection portion of the common passage portion to which each individual passage portion is connected.

  Moreover, it is preferable that the exhaust passage member is provided with a check valve for preventing a backflow of exhaust gas into the secondary battery cell.

  Another aspect of the present invention is a secondary battery pack comprising the secondary battery module as described above.

  Furthermore, another aspect of the present invention provides a secondary battery cell comprising a secondary battery cell having an electrode body in which a positive electrode and a negative electrode are laminated via a separator, and a battery exterior member that houses the electrode body together with a nonaqueous electrolyte. The secondary battery pack is provided with a decompression mechanism for decompressing the inside of the secondary battery cell.

  According to the present invention, the electrode body accommodated in the battery exterior member (case) can be appropriately restrained without restraining the secondary battery cell by the restraining jig. Therefore, fluctuations in output performance can be suppressed, and the secondary battery module and the secondary battery pack can be reduced in size and weight.

  Even when a restraining jig is required, the restraining jig can be simplified. Therefore, even in this case, the secondary battery module and the secondary battery pack can be reduced in size and weight.

It is a figure which shows an example of the usage condition of the secondary battery pack which concerns on this invention. It is a perspective view which shows schematic structure of the secondary battery pack which concerns on this invention. It is a perspective view which shows schematic structure of the secondary battery module which concerns on this invention. It is a figure explaining the internal structure of the secondary battery cell which concerns on this invention. It is a figure explaining schematic structure of the secondary battery module concerning Embodiment 1 of the present invention. It is a block diagram which shows schematic structure of the secondary battery pack which concerns on Embodiment 2 of this invention. 6 is a flowchart illustrating an operation of a secondary battery pack according to Embodiment 2 of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
A vehicle 1 shown in FIG. 1 is an electric vehicle such as an electric vehicle or a hybrid vehicle, for example, and is mounted with a secondary battery pack 10 for supplying electric power to a motor (not shown).

  As shown in FIG. 2, the secondary battery pack 10 includes a pack outer case 13 composed of a pack tray 11 and a pack cover 12, and a secondary battery module 20 accommodated in the pack outer case 13. I have.

  As shown in FIGS. 2 and 3, a plurality of secondary battery modules 20 are accommodated in the secondary battery pack 10 (in the pack outer case 13), and each secondary battery module 20 includes a plurality of secondary battery modules 20. A battery cell 30 is provided.

  In addition, the number of the secondary battery cells 30 with which the secondary battery module 20 is provided is not specifically limited. For example, the secondary battery module 20 may include one secondary battery cell 30.

  Here, each secondary battery cell 30 which comprises the secondary battery module 20 is a sealed battery which is a lithium ion battery, for example, and itself is an existing structure. As shown in FIG. 4, each secondary battery cell 30 has an electrode body 40 including a positive electrode plate 41 and a negative electrode plate 42, and current collectors 50 and 51 together with a nonaqueous electrolyte solution (nonaqueous electrolyte) 60. Housed in a member (case) 70. The upper part of the battery exterior member (case) 70 is sealed with a lid (sealing) member 80.

  Although not shown, an insulating member that covers the inner surface of the battery exterior member (case) 70 is provided in the battery exterior member (case) 70, and the electrode body accommodated in the battery exterior member (case) 70. 40 and current collectors 50 and 51 are insulated.

  One end side of the current collector 50 is connected to the positive electrode plate 41 of the electrode body 40, and the other end side of the current collector 50 projects outside from a through hole 81 provided in the lid (sealing) member 80. A positive terminal member 90 is connected. One end of a current collector 51 is connected to the negative electrode plate 42. The other end side of the current collector 51 is connected to a negative electrode terminal member 100 that protrudes to the outside from a through hole 81 provided in the lid (sealing) member 80.

  Insulating sheet members 110 are provided on the upper and lower surfaces of the lid (sealing) member 80 so as to correspond to the openings of the respective through holes 81. The positive electrode terminal member 90 and the negative electrode terminal member 100 are insulated from the lid (sealing) member 80 by the insulating sheet member 110.

  The electrode body 40 is formed, for example, by laminating a positive electrode plate 41 and a negative electrode plate 42 made of metal foil via a separator (not shown). The electrode body 40 is formed by winding a strip-like positive electrode plate 41 and a negative electrode plate 42 into a flat shape via a separator. The belt-like positive electrode plate 41 and the negative electrode plate 42 are each coated with an active material at a portion where they overlap each other.

  The secondary battery pack 10 includes a plurality of secondary battery cells 30 (secondary battery modules 20) having such a configuration, and each secondary battery cell 30 (within a battery exterior member (case) 70). A pressure reducing mechanism 200 for reducing the pressure is provided.

  In the present embodiment, as shown in FIG. 5, the secondary battery module 20 including a plurality of such secondary battery cells 30 reduces the pressure inside the battery exterior member (case) 70 of each secondary battery cell 30. A mechanism 200 is provided. The secondary battery pack 10 and the secondary battery module 20 according to the present invention are characterized in that the decompression mechanism 200 is provided.

  Specifically, the decompression mechanism 200 includes an exhaust pipe (exhaust passage member) 210 and a vacuum pump 220 provided in the exhaust pipe 210. One end side of the exhaust pipe 210 is connected to the battery exterior member (case) 70 of the secondary battery cell 30 to form a passage for discharging the gas in the battery exterior member (case) 70.

  Moreover, the decompression mechanism 200 according to the present embodiment is provided for each secondary battery module 20. That is, the secondary battery pack 10 includes the same number of decompression mechanisms 200 as the secondary battery module 20. The exhaust pipe 210 includes a plurality of individual passage portions 211 connected to the respective secondary battery cells 30 and a common passage portion 212 to which these individual passage portions 211 are connected. The vacuum pump 220 is provided in the middle of such an exhaust pipe 210.

  For example, the vacuum pump 220 is disposed on the downstream side (downstream side in the flow direction of exhaust gas from the secondary battery cell 30) with respect to the connection portion 212a to which the individual passage portion 211 of the common passage portion 212 is connected. Thereby, the inside of each of the plurality of secondary battery cells 30 constituting the secondary battery module 20 can be decompressed by a single vacuum pump 220.

  In the secondary battery pack 10 of this embodiment, for example, the vacuum pump 220 constituting the decompression mechanism 200 is operated for a predetermined time at a predetermined timing set in advance, for example, when the vehicle 1 is turned on.

  Thereby, the inside of the secondary battery cell 30 is exhausted through the exhaust pipe 210 and decompressed. That is, the inside of the secondary battery cell 30 is in a pressure (negative pressure) state lower than atmospheric pressure, and is preferably in a vacuum state whose pressure is sufficiently lower than atmospheric pressure. In other words, the pressure (atmospheric pressure) toward the inside is applied to the outer surface of the secondary battery cell 30.

  Therefore, the electrode body 40 accommodated in the battery exterior member (case) 70 is restrained by the battery exterior member (case) 70. Even if each secondary battery cell 30 is not restrained by a restraining jig as in the prior art, the electrode body 40 is sufficiently restrained by the battery exterior member (case) 70. Therefore, the fluctuation | variation etc. of the output performance of the secondary battery cell 30 can be suppressed.

  Further, the exhaust pipe 210 is provided with a check valve 230 on the upstream side of the vacuum pump 220 to prevent the backflow of exhaust from the secondary battery cell 30. In the present embodiment, the check valve 230 is disposed close to the vacuum pump 220 on the downstream side of the connection portion 212 a of the common passage portion 212, similarly to the vacuum pump 220.

  Thus, by providing the check valve 230 in the exhaust pipe 210, it is possible to prevent the backflow of the exhaust from each secondary battery cell 30. Therefore, when the inside of the secondary battery cell 30 is depressurized by operating the vacuum pump 220, the inside of each secondary battery cell 30 can be held in a more appropriate negative pressure state (vacuum state).

  As described above, according to the secondary battery pack 10 according to the present embodiment, the electrode body 40 is appropriately disposed without restraining each secondary battery cell 30 included in each secondary battery module 20 with a restraining jig or the like. Can be restrained. Therefore, the secondary battery module 20 can be reduced in size and weight, and accordingly, the secondary battery pack 10 can be reduced in size and weight.

  In the secondary battery module 20 according to the present embodiment, each secondary battery cell 30 may be restrained by a restraining member (not shown) as necessary. Even in this case, the restraining pressure for restraining the secondary battery cell 30 by the restraining member may be lower than the conventional one. Therefore, the restraining member can be reduced in size and weight, and accordingly, the secondary battery module 20 and the secondary battery pack 10 can be reduced in size and weight.

  By the way, the arrangement of the vacuum pump 220 is not particularly limited, but is preferably arranged outside the pack outer case 13 constituting the secondary battery pack 10. It is preferable that the exhaust pipe 210 is extended from each secondary battery cell 30 to the outside of the pack outer case 13 and connected to the vacuum pump 220 on the outer side of the pack outer case 13.

  By setting it as such a structure, size reduction and weight reduction of the pack exterior case 13 in which the secondary battery cell 30 was accommodated can be achieved. Since the pack outer case 13 is reduced in size and weight, the secondary battery pack 10 including the vacuum pump 220 can be easily mounted on the vehicle 1.

  Further, the connection position of the exhaust pipe 210 (individual passage portion 211) with the battery exterior member (case) 70 is not particularly limited, but is connected to the upper portion of the battery exterior member (case) 70 in the state where it is mounted on the vehicle 1. Preferably it is. Further, the exhaust pipe 210 may be connected to a lid (sealing) member 80 that seals the upper portion of the battery exterior member (case) 70.

  That is, the exhaust pipe 210 is located above the liquid surface of the nonaqueous electrolyte solution 60 accommodated in the battery exterior member (case) 70, and the secondary battery cell 30 (battery exterior member (case) 70, lid (sealing)). It is preferably connected to the member 80) (see FIG. 4). Thereby, the gas in the battery exterior member (case) 70 can be easily discharged to the outside through the exhaust pipe 210.

(Embodiment 2)
FIG. 6 is a block diagram illustrating a schematic configuration of the secondary battery pack 10 according to the second embodiment. FIG. 7 illustrates an example of the operation of the secondary battery pack 10 according to the second embodiment, in particular, the operation of the decompression mechanism. It is a flowchart to explain. In the drawings, the same members are denoted by the same reference numerals, and redundant description is omitted.

  In the above-described embodiment, the inside of the battery exterior member (case) 70 is held in a negative pressure state (preferably a vacuum state) by operating the vacuum pump 220 at a predetermined timing set in advance. The embodiment is an example in which the vacuum pump 220 is operated in accordance with the internal pressure of the battery exterior member (case) 70.

  Specifically, as shown in FIG. 6, the secondary battery pack 10 according to the present embodiment includes a control unit (control device) 300 that controls the operating state of the vacuum pump 220 included in each secondary battery module 20. ing. The control unit 300 includes, for example, an input / output device, a storage device (ROM, RAM, etc.), a central processing unit (CPU), a timer counter, and the like. In FIG. 6, only one vacuum pump 220 is illustrated, but the control unit 300 controls each of the vacuum pumps 220 included in each secondary battery module.

  A pressure sensor 310 that detects the pressure (internal pressure) in the secondary battery cell 30 is provided in the battery exterior member (case) 70 of each secondary battery cell 30. The control unit 300 operates each vacuum pump 220 according to the detection result of the pressure sensor 310.

  Specifically, as shown in the flowchart of FIG. 7, when the power of the vehicle 1 is turned on, the control unit 300 is based on the detection result of the pressure sensor 310 provided in each secondary battery cell 30 in step S1. Then, it is determined whether or not the pressure Pr in the secondary battery cell 30 is higher than a preset first threshold value P1 (internal pressure determination).

  Here, when the internal pressure Pr of the secondary battery cell 30 is higher than the first threshold value P1 (step S1: Yes), the process proceeds to step S2, the vacuum pump 220 is operated, and the interior of the secondary battery cell 30 is maintained. Reduce pressure. Thereafter, in step S3, it is determined whether or not the internal pressure Pr of each secondary battery cell 30 has become lower than a preset second threshold value P2 (<P1) (internal pressure determination).

  And if the internal pressure Pr of each secondary battery cell 30 becomes lower than the 2nd threshold value P2 (step S3: Yes), the vacuum pump 220 will be stopped by step S4 (pump control). In other words, the vacuum pump 220 is operated until the pressure Pr in each secondary battery cell 30 becomes lower than the second threshold value P2. And while the power supply of the vehicle 1 is turned on, this series of processes is repeatedly performed.

  Thus, in this embodiment, since the vacuum pump 220 was operated according to the internal pressure of each secondary battery cell 30, the internal pressure of each secondary battery cell 30 can be adjusted more appropriately.

  In the present embodiment, the internal pressure of each secondary battery cell 30 is detected, and the operation state of the vacuum pump 220 is controlled according to the detection result. However, the control method of the vacuum pump 220 is limited to this. Is not to be done. For example, the displacement of the battery exterior member (case) 70 may be detected, and the operating state of the vacuum pump 220 may be controlled according to the detection result.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment. The present invention can be modified as appropriate without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the check valve is provided in the common passage portion of the exhaust pipe. However, the present invention is not limited to this, and a plurality of check valves corresponding to the respective secondary battery cells are provided in the individual passage portion. Each may be provided.

  Moreover, although the structure which provided the decompression mechanism (vacuum pump) for every secondary battery module was illustrated in the above-mentioned embodiment, the number of decompression mechanisms with which a secondary battery pack is provided is not specifically limited. The secondary battery pack only needs to include at least one decompression mechanism. Although depending on the performance of the vacuum pump, the inside of all the secondary battery cells included in the secondary battery pack may be decompressed with a single vacuum pump. Of course, a decompression mechanism may be provided for each secondary battery cell.

  In the above-described embodiment, the present invention has been described by taking, as an example, a secondary battery module and a secondary battery pack that include a secondary battery cell in which an electrode body is housed in a battery exterior member (case) together with a non-aqueous electrolyte. The configuration of the secondary battery cell is not limited to this, and may be a so-called all-solid battery in which the non-aqueous electrolyte is replaced with a solid electrolyte layer to solidify the battery. Even in a secondary battery module and a secondary battery pack that accommodate such an all-solid battery, it is possible to reduce the size and weight as in the above-described embodiment.

  Furthermore, in the above-described embodiment, a rectangular battery case is exemplified as the battery exterior member, but the battery exterior member may be, for example, a pouch-type. Of course, even when a pouch-type battery exterior member is used, the secondary battery module and the secondary battery pack can be reduced in size and weight as in the above-described embodiment.

  In the above-described embodiment, the present invention has been described by taking a secondary battery module and a secondary battery pack for a vehicle as an example. However, the present invention is not limited to a vehicle, but is used for other purposes. The present invention can also be applied to battery modules and secondary battery packs.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Secondary battery pack 11 Pack tray 12 Pack cover 13 Pack exterior case 20 Secondary battery module 30 Secondary battery cell 40 Electrode body 41 Positive electrode plate 42 Negative electrode plate 50, 51 Current collector 60 Non-aqueous electrolyte 70 Battery exterior Member (case)
80 Lid (sealing) member 81 Through-hole 90 Positive electrode terminal member 100 Negative electrode terminal member 110 Insulating sheet member 200 Pressure reducing mechanism 210 Exhaust pipe 211 Individual passage portion 212 Common passage portion 220 Vacuum pump 230 Check valve 300 Control portion 310 Pressure sensor

Claims (6)

A secondary battery module comprising a secondary battery cell having an electrode body in which a positive electrode and a negative electrode are stacked via a separator, and a battery exterior member that houses the electrode body together with a nonaqueous electrolyte,
A secondary battery module comprising a decompression mechanism for decompressing the inside of the secondary battery cell. The secondary battery module according to claim 1,
The decompression mechanism includes an exhaust passage member connected to the battery exterior member, and a vacuum pump provided in the exhaust passage member and exhausting the inside of the secondary battery cell to decompress the secondary battery cell. Battery module. The secondary battery module according to claim 2,
A plurality of the secondary battery cells,
The exhaust passage member includes an individual passage portion connected to the battery exterior member of each secondary battery cell, and a common passage portion to which each individual passage portion is connected,
The secondary battery module, wherein the vacuum pump is disposed downstream of a connection portion of the common passage portion to which each individual passage portion is connected. The secondary battery module according to claim 2 or 3,
The secondary battery module, wherein the exhaust passage member is provided with a check valve for preventing a reverse flow of exhaust gas into the secondary battery cell.   A secondary battery pack comprising the secondary battery module according to claim 1. A secondary battery pack comprising a secondary battery cell having an electrode body in which a positive electrode and a negative electrode are laminated via a separator, and a battery exterior member that houses the electrode body together with a nonaqueous electrolyte,
A secondary battery pack comprising a decompression mechanism for decompressing the inside of the secondary battery cell.