Battery module

Abstract

This battery module 1 comprises: a pouch-type battery cell 2 having a battery part 3, which has a plurality of positive electrode plates 311 and negative electrode plates 312 that are laminated and an electrolytic solution 32, and an exterior material 4, which covers the battery part 3; and an interposed plate 5 for reducing the internal pressure of the exterior material 4 when the pouch-type battery cell 2 expands. The pouch-type battery cell 2 includes: a battery housing part 2a in which the battery part 3 is inserted in the exterior material 4; and a seal part 2b in which the exterior material 4 is sealed around the battery housing part 2a. The interposed plate 5 has at least: a plate part 51 facing the seal part 2b of the pouch-type battery 2; and a protrusion part 52 which protrudes from the plate part 51 and which breaks through the exterior material 4 when the pouch-type battery 2 expands. A ventilation groove 520, through which gas discharged from an opening 40 formed in the exterior material 4 by the protrusion part 52 flows, is formed in a side face 52a of the protrusion part 52.

Description

Battery module

[0001] The present invention relates to a battery module having pouch-type battery cells each having a plurality of stacked electrode plates and an electrolyte solution covered with an exterior material.

[0002] Conventionally, battery modules having secondary battery cells each including a plurality of stacked electrode plates and an electrolyte solution covered with an exterior material have been used as a power source for, for example, driving electric vehicles. When the secondary battery cells are overheated due to an increase in temperature caused by, for example, overcharging or overdischarging, the electrolyte solution may evaporate and expand. Patent Documents 1 and 2 describe a configuration in which, when the secondary battery cells expand, holes are drilled in the exterior material to reduce the internal pressure, thereby preventing the exterior material from bursting due to internal pressure even when the secondary battery cells expand.

[0003] The explosion-proof energy storage module described in Patent Document 1 has stack plates disposed between a plurality of energy storage cells, each of which has a cutting blade that comes into contact with the outer edge of a container that expands due to an increase in internal pressure and tears the container open. The cutting blade is a metal plate-shaped member fixed to the stack plate, which is made of a resin material.

[0004] The battery module described in Patent Document 2 includes a battery in which battery elements such as multiple electrodes and an electrolyte are sealed in an exterior laminate, and a case that houses the battery. The case is provided with a protrusion for breaking the exterior laminate in the event of battery expansion. A through-hole is formed in the center of the protrusion, leading to the outside of the case.

[0005] JP 2011-249428 A JP 2003-168410 A

[0006] In a configuration in which the container of the energy storage cell is split open with a cutting blade, even if a hole is made in the container, the hole may be blocked by the cutting blade, and the internal pressure of the container may not be reduced sufficiently. Also, in a case in which a protrusion with a through hole formed therein is provided on the case, as in the case of Patent Document 2, if a part of the exterior laminate is cut off at the periphery of the opening of the through hole in the protrusion and becomes a piece, this piece may clog the through hole, and the pressure inside the exterior laminate may not be reduced sufficiently.

[0007] Therefore, an object of the present invention is to provide a battery module that can reliably reduce the internal pressure of an exterior material when a pouch-type battery, which is made up of a plurality of stacked electrode plates and an electrolyte solution covered by an exterior material, expands.

[0008] In order to achieve the above-mentioned object, the present invention provides a battery module comprising: at least one pouch-type battery cell having a battery section having a plurality of stacked electrode plates and an electrolyte and an exterior material covering the battery section; and an explosion-proof member that reduces the internal pressure of the exterior material when the pouch-type battery cell expands, wherein the pouch-type battery cell has a battery housing section in which the battery section is sandwiched between the exterior material and a seal section in which the exterior material is sealed around the battery housing section, and the explosion-proof member has at least a plate section that faces the seal section of the pouch-type battery and a protrusion that protrudes from the plate section and pierces the exterior material when the pouch-type battery expands, and a ventilation groove is formed on the side of the protrusion through which gas flows that is exhausted from an opening formed in the exterior material by the protrusion.

[0009] According to the present invention, when a pouch-type battery in which a plurality of stacked electrode plates and an electrolyte solution are covered by an exterior material expands, it is possible to reduce the internal pressure of the exterior material with high reliability.

[0010] FIG. 1 is an external view of a battery module according to an embodiment. FIG. 2 is a cross-sectional view of the battery module taken along line A-A in FIG. 1. FIG. 3 is a cross-sectional view of the battery module taken along line B-B in FIG. 1. FIG. 4 is a cross-sectional view schematically illustrating an example structure of a pouch-type battery cell. FIG. 5 is an exploded perspective view of a battery pack. FIG. 6 is a perspective cross-sectional view showing a portion of a battery pack. FIG. 7A is a perspective view of an intervening plate. FIG. 7B is a perspective view of an intervening plate. FIG. 8 is an explanatory diagram showing an expanded state of a pouch-type battery cell. FIG. 9 is a structural diagram of a protrusion provided on a plate portion as viewed from six directions. A perspective view of the protrusion and its periphery, including a cross section of the plate portion of the intervening plate, taken along line D-D in FIG. 9. A perspective view of the protrusion and its periphery, including a cross section of the plate portion of the intervening plate, taken along line D-D in FIG. 9. FIG. 11 is a perspective view of a protrusion according to Modification 1. FIG. 12 is a perspective view of a protrusion according to Modification 2. FIG. 13 is a perspective view of a protrusion according to Modification 3. FIG. 14 is a perspective view of a protrusion according to Modification 4. Fig. 15 is a perspective view showing a protrusion according to Modification 5. Fig. 16 is a perspective view showing a protrusion according to Modification 6.

[0011] [Embodiments] The following describes embodiments of the present invention with reference to the drawings. Note that the embodiments and modifications described below are shown as preferred specific examples for carrying out the present invention, and while some of them specifically exemplify various technically preferred aspects, the technical scope of the present invention is not limited to these specific embodiments.

[0012] Fig. 1 is an external view of a battery module 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the battery module 1 taken along line A-A in Fig. 1. Fig. 3 is a cross-sectional view of the battery module 1 taken along line B-B in Fig. 1. The battery module 1 is used, for example, as a power source for a vehicle having an electric motor as a driving source for traveling.

[0013] The battery module 1 includes a resin case 10 formed by assembling first to third case members 11 to 13, a battery pack 100 housed in the case 10, first to fifth bus bars 101 to 105, and a control circuit 14. The first to third case members 11 to 13 are made of a thermoplastic resin such as PBT (polybutylene terephthalate). The first case member 11 and the second case member 12, and the second case member 12 and the third case member 13 are hermetically welded together.

[0014] The first case member 11 houses a battery pack 100. In Fig. 1, the first case member 11 is indicated by a two-dot chain line, and the battery pack 100 housed therein is indicated by a solid line. The battery pack 100 has a plurality of pouch-type battery cells 2. The second case member 12 houses a control circuit 14.

[0015] The control circuit 14 monitors the voltage of each pouch-type battery cell 2 and communicates with a higher-level control device via a communication line connected to a connector 121 provided on the second case member 12. The control circuit 14 has a circuit board 141 and multiple electronic components 142, such as ICs, resistors, and capacitors, mounted on the circuit board 141. The circuit board 141 is fixed to the second case member 12 with multiple bolts 143.

[0016] 2, the second case member 12 is provided with a communication hole 120 that connects the internal space of the first case member 11 with the internal space of the second case member 12. The third case member 13 is provided with a through hole 130 that is closed by a cap 15. The cap 15 prevents foreign matter from entering the inside of the case 10 through the through hole 130. When the difference in air pressure between the inside and outside of the case 10 becomes large, air flows through the through hole 130, and the air pressure difference is alleviated.

[0017] In this embodiment, the battery pack 100 has four pouch-type battery cells 2. The pouch-type battery cells 2 are secondary batteries that can be charged and discharged. Each pouch-type battery cell 2 has a positive electrode tab 201 and a negative electrode tab 202. The four pouch-type battery cells 2 are aligned in the direction indicated by arrow C in FIG. 1 . This alignment direction corresponds to the width direction of the first case member 11. Hereinafter, when each of the four pouch-type battery cells 2 is specifically described, the four pouch-type battery cells 2 will be referred to as first to fourth pouch-type battery cells 21 to 24. The positive electrode tabs 201 and negative electrode tabs 202 of the first to fourth pouch-type battery cells 21 to 24 are electrically connected in series.

[0018] A first bus bar 101 is connected to the positive electrode tab 201 of the first pouch-type battery cell 21. A second bus bar 102 is connected to a connection portion 200a between the negative electrode tab 202 of the first pouch-type battery cell 21 and the positive electrode tab 201 of the second pouch-type battery cell 22. A third bus bar 103 is connected to a connection portion 200b between the negative electrode tab 202 of the second pouch-type battery cell 22 and the positive electrode tab 201 of the third pouch-type battery cell 23. A fourth bus bar 104 is connected to a connection portion 200c between the negative electrode tab 202 of the third pouch-type battery cell 23 and the positive electrode tab 201 of the fourth pouch-type battery cell 24. A fifth bus bar 105 is connected to the negative electrode tab 202 of the fourth pouch-type battery cell 24. The control circuit 14 receives the potentials of the first to fifth bus bars 101 to 105 .

[0019] 4 is a cross-sectional view schematically showing an example of the structure of the pouch-type battery cell 2. The pouch-type battery cell 2 is a lithium-ion secondary battery that uses lithium ions as electrolyte ions, and more specifically, a lithium-ion capacitor.

[0020] The pouch-type battery cell 2 includes a positive electrode tab 201, a negative electrode tab 202, a storage unit 31 that stores electric charge, an electrolytic solution 32 containing an organic solvent (nonaqueous solvent) and an electrolyte, and an exterior material 4 that seals the electrolytic solution 32. The storage unit 31 includes a plurality of positive electrode plates 311 and a plurality of negative electrode plates 312 that are alternately arranged and stacked, and a plurality of separators 313 that are arranged between the plurality of positive electrode plates 311 and the plurality of negative electrode plates 312. The plurality of positive electrode plates 311 and the plurality of negative electrode plates 312 correspond to the plurality of electrode plates in the present invention. The storage unit 31 and the electrolytic solution 32 constitute a battery unit 3 that is covered with the exterior material 4.

[0021] The positive electrode plate 311 has a thin current collector 311a and a positive electrode active material layer 311b coated on both sides of the current collector 311a. The positive electrode active material layer 311b contains a positive electrode active material with a large specific surface area and high conductivity, and a conductive additive for improving the electrical conductivity of the positive electrode active material layer 311b. The negative electrode plate 312 has a thin current collector 312a and a negative electrode active material layer 312b coated on both sides of the current collector 312a. The negative electrode active material layer 312b contains lithium ion Li ＋ The negative electrode active material is provided with a negative electrode active material capable of absorbing and releasing lithium ions (Li ＋ ) is pre-doped.

[0022] The electrolyte 32 is contained in an exterior packaging material 4 together with a plurality of positive electrode plates 311, a plurality of negative electrode plates 312, and a plurality of separators 313, and is sealed within the exterior packaging material 4. The positive electrode tab 201 is electrically connected to the current collectors 311a of the plurality of positive electrode plates 311 inside the exterior packaging material 4. The negative electrode tab 202 is electrically connected to the current collectors 312a of the plurality of negative electrode plates 312 inside the exterior packaging material 4. The positive electrode tab 201 and the negative electrode tab 202 are partially exposed to the outside of the exterior packaging material 4. A heat-sealing resin 400 is interposed between the exterior packaging material 4 and the positive electrode tab 201 and the negative electrode tab 202.

[0023] The exterior material 4 is made of a laminate film having a core sheet 401, an inner sheet 402 bonded to the inner surface of the core sheet 401, and an outer sheet 403 bonded to the outer surface of the core sheet 401. The core sheet 401 is aluminum foil. The inner sheet 402 is a resin sheet such as polypropylene. The outer sheet 403 is a resin sheet such as nylon PET film.

[0024] The exterior casing 4 has a front surface 41 and a back surface 42 that sandwich the battery section 3, and the front surface 41 and the back surface 42 are heat-sealed around the periphery of the pouch-type battery cell 2. In the following description, the battery housing section 2a refers to the portion where the battery section 3 is sandwiched between the front surface 41 and the back surface 42 of the exterior casing 4, and the sealed portion 2b refers to the portion where the exterior casing 4 is sealed around the battery housing section 2a. The sealed portion 2b seals the electrolyte 32 and prevents it from leaking outside the exterior casing 4.

[0025] If the pouch-type battery cells 2 are overheated due to temperature rise caused by overcharging or overdischarging, for example, the electrolyte 32 may evaporate and expand. If the pouch-type battery cells 2 expand excessively, the case 10 may be damaged. Therefore, the battery pack 100 of this embodiment has an interposing plate 5 as an explosion-proof member that punctures the exterior packaging material 4 to reduce the internal pressure of the exterior packaging material 4 when the pouch-type battery cells 2 expand.

[0026] Fig. 5 is an exploded perspective view of the battery pack 100. Fig. 6 is a perspective cross-sectional view showing a portion of the battery pack 100. Fig. 7A is a perspective view showing the interposing plate 5. Fig. 7B is a perspective view of the interposing plate 5 seen from a different direction than Fig. 7A.

[0027] In this embodiment, an interposing plate 5 is disposed between the first pouch-type battery cell 21 and the second pouch-type battery cell 22, and between the third pouch-type battery cell 23 and the fourth pouch-type battery cell 24. The interposing plate 5 is, for example, an injection-molded resin body. However, the interposing plate 5 is not limited to being made of resin and may be made of metal, for example.

[0028] The interposing plate 5 integrally includes a flat plate portion 51, multiple protrusions 52 protruding from the plate portion 51, and spacing retainers 53 provided at the ends of the plate portion 51. The plate portion 51 is rectangular and corresponds in size to the pouch-shaped battery cell 2, with a portion of it facing the seal portion 2b of the pouch-shaped battery cell 2. In other words, the plate portion 51 faces at least the seal portion 2b of the pouch-shaped battery cell 2. In this embodiment, the alignment direction of the positive electrode tab 201 and negative electrode tab 202 of the pouch-shaped battery cell 2 is the longitudinal direction of the plate portion 51, and both longitudinal ends of the plate portion 51 face the seal portion 2b of the pouch-shaped battery cell 2. However, the shape of the plate portion 51 may also be such that the alignment direction of the positive electrode tab 201 and negative electrode tab 202 is the lateral direction.

[0029] The plate portion 51 of the intervening plate 5 between the first pouch-type battery cell 21 and the second pouch-type battery cell 22 has one surface 51a facing the seal portion 2b of the first pouch-type battery cell 21 and the other surface 51b facing the seal portion 2b of the second pouch-type battery cell 22. The plate portion 51 of the intervening plate 5 between the third pouch-type battery cell 23 and the fourth pouch-type battery cell 24 has one surface 51a facing the seal portion 2b of the third pouch-type battery cell 23 and the other surface 51b facing the seal portion 2b of the fourth pouch-type battery cell 24.

[0030] The multiple protrusions 52 are provided on the plate portion 51 in the portion facing the seal portion 2b of the first to fourth pouch-type battery cells 21 to 24, protruding in the thickness direction of the plate portion 51 from one surface 51a and the other surface 51b of the plate portion 51. On one surface 51a of the plate portion 51, protrusions 52 are provided at two locations that sandwich the battery housing portion 2a in a direction parallel to the plate portion 51. Similarly, on the other surface 51b of the plate portion 51, protrusions 52 are provided at two locations that sandwich the battery housing portion 2a in a direction parallel to the plate portion 51.

[0031] The number of protrusions 52 on the intervening plate 5 is not limited to this, and one protrusion 52 may be provided on each of the one surface 51a and the other surface 51b of the plate portion 51, or three or more protrusions 52 may be provided on each of the one surface 51a and the other surface 51b of the plate portion 51. However, it is desirable to provide protrusions 52 in at least two locations on each of the one surface 51a and the other surface 51b of the plate portion 51 so that gas can be reliably discharged from within the exterior material 4 when the pouch-type battery cell 2 expands.

[0032] In this embodiment, two protrusions 52 are provided on each of the one surface 51a and the other surface 51b of the plate portion 51, at positions symmetrical with respect to the center position 500 (see Figures 7A and 7B) of the plate portion 51, which is aligned with the center of the battery accommodating section 2a along the arrangement direction of the multiple pouch-type battery cells 2.

[0033] The spacing retaining portion 53 maintains the distance between the seal portions 2b of the two pouch-shaped battery cells 2 that sandwich the intervening plate 5. More specifically, of the two intervening plates 5 of the battery pack 100, the spacing retaining portion 53 of one intervening plate 5 that is interposed between the first pouch-shaped battery cell 21 and the second pouch-shaped battery cell 22 maintains the distance between the seal portion 2b of the first pouch-shaped battery cell 21 and the seal portion 2b of the second pouch-shaped battery cell 22. The spacing retaining portion 53 of the other intervening plate 5 that is interposed between the third pouch-shaped battery cell 23 and the fourth pouch-shaped battery cell 24 maintains the distance between the seal portion 2b of the third pouch-shaped battery cell 23 and the seal portion 2b of the fourth pouch-shaped battery cell 24.

[0034] The spacing retaining portions 53 are located farther from the center position 500 of the plate portion 51 than the protrusions 52 are. In this embodiment, spacing retaining portions 53 are provided at both ends of the long sides of the rectangular plate portion 51. The protrusions 52 are located near the spacing retaining portions 53, and the spacing retaining portions 53 prevent contact between the exterior packaging 4 and the protrusions 52 when the pouch-type battery cell 2 is not expanded.

[0035] One intervening plate 5 is fixed to the first pouch-type battery cell 21, and the other intervening plate 5 is fixed to the third pouch-type battery cell 23. In this embodiment, as shown in Figure 3, the plate portion 51 of one intervening plate 5 is fixed to the exterior material 4 of the first pouch-type battery cell 21 with double-sided tape 16, and the plate portion 51 of the other intervening plate 5 is fixed to the exterior material 4 of the third pouch-type battery cell 23 with double-sided tape 16.

[0036] 2 and 3 , the first case member 11 that houses the battery pack 100 is a rectangular parallelepiped having a bottom wall 110 and four side walls 111 to 114, with the battery pack 100 disposed between a pair of side walls 111, 113 that face each other in the arrangement direction of the first to fourth pouch-shaped battery cells 21 to 24. Sheet-like spacers 17 are disposed between the first pouch-shaped battery cell 21 and the side wall 111, between one intervening plate 5 and the second pouch-shaped battery cell 22, between the second pouch-shaped battery cell 22 and the third pouch-shaped battery cell 23, between the other intervening plate 5 and the fourth pouch-shaped battery cell 24, and between the fourth pouch-shaped battery cell 24 and the side wall 113.

[0037] A support plate 18 that supports the first through fourth pouch-type battery cells 21 through 24 is disposed in contact with the bottom wall 110 at the bottom of the first case member 11. Grooves are formed in the support plate 18 to accommodate portions of the seal portions 2b of the first through fourth pouch-type battery cells 21 through 24.

[0038] Figure 8 is an explanatory diagram showing the state of the battery pack 100 when the pouch-type battery cell 2 expands. When the pouch-type battery cell 2 expands, the protrusion 52 breaks through the exterior packaging 4, releasing gas generated inside the exterior packaging 4 and reducing the internal pressure of the exterior packaging 4. Next, the configuration of the protrusion 52 and its surrounding area will be described in detail with reference to Figures 9, 10A, and 10B.

[0039] 9 is a configuration diagram showing the protrusions 52 provided on one surface 51a and the other surface 51b of the plate portion 51 as viewed from six directions. Figures 10A and 10B are perspective views of the protrusions 52 and their surroundings, including a cross section of the plate portion 51 taken along line DD in Figure 9.

[0040] The shape of the protrusion 52 when viewed from the longitudinal direction of the spacing portion 53 along the short side direction of the plate portion 51 is a right-angled triangle. The side surface 52a of the protrusion 52 includes a pair of flat surfaces 52b, 52c of a right-angled triangle perpendicular to the short side direction of the plate portion 51, a sloped surface 52d corresponding to the hypotenuse of the right-angled triangle, and a vertical surface 52e corresponding to the opposite side of the right-angled triangle. The flat surfaces 52b, 52c and the vertical surface 52e are perpendicular to the one surface 51a and the other surface 51b of the plate portion 51. The sloped surface 52d is inclined with respect to the one surface 51a and the other surface 51b of the plate portion 51.

[0041] As shown in FIG. 9, the inclination angle θ of the inclined surface 52d with respect to the one surface 51a and the other surface 51b of the plate portion 51 as viewed in the longitudinal direction of the spacing retaining portion 53 is １ , and the inclination angle θ of the inclined surface 52d with respect to the vertical surface 52e ２ are, for example, 45°. However, the present invention is not limited to this, and for example, the inclination angle θ １ , θ ２ may be 30° or more and 60° or less.

[0042] When the pouch-type battery cell 2 expands, the internal pressure of the exterior packaging material 4 presses the exterior packaging material 4 against the tip 52f of the protrusion 52, forming an opening 40 in the exterior packaging material 4 as shown in Figure 8. The opening 40 is where the exterior packaging material 4 is torn by the acute tip 52f of the protrusion 52. The protrusion 52 has a ventilation groove 520 formed therein, through which gas discharged from the opening 40 in the exterior packaging material 4 flows. The ventilation groove 520 is formed on the side surface 52a of the protrusion 52. In other words, the ventilation groove 520 is formed so as to be recessed from the side surface 52a of the protrusion 52, and the ventilation groove 520 is open to the side surface 52a of the protrusion 52.

[0043] In this embodiment, the ventilation groove 520 is formed as a dividing groove that divides the protrusion 52 into a pair of segments 521, 522. The pair of segments 521, 522 have the same size and shape. The ventilation groove 520 extends from the tip 52f of the protrusion 52 toward the plate portion 51. The ventilation groove 520 is formed in a range where one end of the ventilation groove 520 reaches the plate portion 51. More specifically, the ventilation groove 520 is formed over the entire inclined surface 52d and vertical surface 52e of the protrusion 52 in a direction perpendicular to the plate portion 51.

[0044] An air passage 510 communicating with the air groove 520 of the protrusion 52 is formed in the plate portion 51. In this embodiment, the air passage 510 is formed penetrating the plate portion 51 in the thickness direction. Also, in this embodiment, the air groove 520 of the protrusion 52 provided on one surface 51a of the plate portion 51 and the air groove 520 of the protrusion 52 provided on the other surface 51b are communicated with each other via the air passage 510 formed in the plate portion 51. However, the air passage 510 does not necessarily have to be formed penetrating the plate portion 51. For example, the air passage 510 communicating with the air groove 520 may be formed in the plate portion 51 by grooves formed on the one surface 51a and the other surface 51b of the plate portion 51.

[0045] In the present embodiment, a notch 530 is formed in the spacing retaining portion 53, and the ventilation path 510 of the plate portion 51 communicates with the notch 530. The gas discharged from the opening 40 of the exterior material 4 flows through a flow path 50 consisting of the ventilation groove 520 of the protrusion 52, the ventilation path 510 of the plate portion 51, and the notch 530 of the spacing retaining portion 53, as shown in Fig. 8, and is then released to the outside of the case 10 through the communication hole 120 of the second case member 12 and the through-hole 130 of the third case member 13.

[0046] Effects of the Embodiment According to the embodiment described above, the configuration in which the ventilation grooves 520 are formed on the side surfaces 52a of the protrusions 52 prevents the openings 40 in the exterior material 4 from being blocked by the protrusions 52, allowing gas within the exterior material 4 to be smoothly discharged to the outside of the case 10 when the pouch-type battery cell 2 expands. Furthermore, as shown in FIG. 8 , even if the expanded exterior material 4 comes into contact with the plate portion 51 around the protrusions 52, gas within the exterior material 4 can be discharged through the flow path 50, which includes the ventilation grooves 520 in the protrusions 52, the ventilation paths 510 in the plate portion 51, and the notches 530 in the spacing portions 53. Furthermore, according to the present embodiment, the protrusions 52 have a right-angled triangular shape, which facilitates mold removal during injection molding of the interposer plate 5, and makes it easy to ensure the strength of the protrusions 52. This makes it possible to reduce the internal pressure of the exterior material 4 with high reliability.

[0047] Modifications Next, modifications of the embodiment will be described with reference to Figures 11 to 16. In these modifications, the shape of the protrusion 52 of the interposition plate 5 according to the embodiment is modified, and although the protrusion and its surrounding area provided on one surface 51a of the plate portion 51 are shown, a similar protrusion is also formed on the other surface 51b of the plate portion 51. Also, the spacing retaining portion 53 is not shown in Figures 11 to 16.

[0048] Fig. 11 is a perspective view showing a portion of an intervening plate 5A having a protruding portion 52A according to Modification 1. Fig. 12 is a perspective view showing a portion of an intervening plate 5B having a protruding portion 52B according to Modification 2. Fig. 13 is a perspective view showing a portion of an intervening plate 5C having a protruding portion 52C according to Modification 3. Fig. 14 is a perspective view showing a portion of an intervening plate 5D having a protruding portion 52D according to Modification 4.

[0049] Like the protrusion 52 according to the embodiment, the protrusions 52A, 52B, 52C, and 52D have a right-angled triangular shape when viewed from the short side of the plate portion 51. The side surface 52a of each of the protrusions 52A, 52B, 52C, and 52D has a pair of right-angled triangular flat surfaces 52b and 52c, an inclined surface 52d, and a vertical surface 52e, similar to the above embodiment, but the locations where the ventilation grooves are formed are different. The ventilation passages 510 formed in the plate portions 51 of the intervening plates 5A, 5B, 5C, and 5D communicate with the notches 530 formed in the spacing portions 53, similar to the embodiment.

[0050] In Modification 1 shown in FIG. 11 , a ventilation groove 520A is formed on the inclined surface 52d of the protrusion 52A. The ventilation groove 520A is formed in a range from near the tip 52f of the protrusion 52A to the plate portion 51 and communicates with the ventilation path 510 formed by penetrating the plate portion 51, but the ventilation groove 520A is not formed on the tip 52f of the protrusion 52A. Furthermore, the ventilation groove 520A does not open to the vertical surface 52e of the protrusion 52A. However, the ventilation groove 520A may open to the inclined surface 52d and the vertical surface 52e of the protrusion 52A.

[0051] 12, a ventilation groove 520B is formed in the vertical surface 52e of the protrusion 52B. The ventilation groove 520B is formed in the range from the tip 52f of the protrusion 52B to the plate portion 51, and is connected to a groove-shaped ventilation passage 510 formed in one surface 51a of the plate portion 51.

[0052] 13 , a pair of flat surfaces 52b, 52c of protrusion 52C are each formed with ventilation grooves 520C. These ventilation grooves 520C open to inclined surface 52d at the center of the height direction of protrusion 52C perpendicular to plate 51, and are formed in a range extending to plate 51 along a direction perpendicular to plate 51. Groove-shaped ventilation paths 510 are formed on one surface 51a of plate 51, and are connected to each of ventilation grooves 520C.

[0053] 14, a ventilation groove 520D is formed in one flat surface 52b of a pair of flat surfaces 52b, 52c of a protrusion 52D, but the ventilation groove 520D does not open to the inclined surface 52d. The ventilation groove 520D is formed in a range from the vicinity of the inclined surface 52d to the plate portion 51, and communicates with an ventilation passage 510 formed in a groove shape in one surface 51a of the plate portion 51.

[0054] 15 is a perspective view showing a portion of an interposer plate 5E having a protrusion 52E according to Modification 5. The protrusion 52E is cylindrical and disposed perpendicular to the plate portion 51, with a tip surface 52g thereof being a flat surface inclined with respect to the central axis of the protrusion 52E. A ventilation groove 520E is formed in a side surface 52h of the protrusion 52E parallel to the central axis of the protrusion 52E. The ventilation groove 520E is formed in a range from the tip surface 52g to the plate portion 51. A groove-shaped ventilation passage 510 communicating with the ventilation groove 520E is formed in one surface 51a of the plate portion 51.

[0055] 16 is a perspective view showing a portion of an interposer plate 5F having a protrusion 52F according to Modification 6. Like the above-described embodiment, the protrusion 52F has a right-angled triangular shape when viewed from the short side of the plate 51. The protrusion 52F has flat surfaces 52b and 52c perpendicular to the short side of the plate 51, a sloped surface 52d, and a vertical surface 52e. Two ventilation grooves 520F are formed by a notch formed in one of the flat surfaces 52b. Each ventilation groove 520F is formed at a corner of the protrusion 52F so as to be recessed from one flat surface 52b toward the other flat surface 52c, and opens into the sloped surface 52d. The portion of the protrusion 52F between the two ventilation grooves 520F forms a protrusion 524 that protrudes from a main body 523 including the right-angled triangular flat surface 52c, the sloped surface 52d, and the vertical surface 52e. The ventilation groove 520F is formed in the range from the inclined surface 52d to the plate portion 51, and communicates with a groove-shaped ventilation passage 510 formed in one surface 51a of the plate portion 51.

[0056] These modified examples also prevent the opening 40 of the exterior material 4 from being blocked by the protrusions 52A to 52F, allowing the gas inside the exterior material 4 to be smoothly discharged to the outside of the case 10 when the pouch-type battery cell 2 expands, making it possible to reduce the internal pressure of the exterior material 4 with high reliability.

[0057] (Note) While the present invention has been described above based on embodiments and modifications, these embodiments and modifications do not limit the scope of the invention as claimed. It should be noted that not all of the combinations of features described in the embodiments and modifications are necessarily essential to the means for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented by omitting some components or adding or substituting components within the scope of the spirit of the invention, and modifications such as those described below are also possible.

[0058] In the above embodiment, the present invention has been described as being applied to a lithium ion capacitor, which can charge and discharge faster than a typical lithium ion battery, but the present invention is not limited to this and can also be applied to secondary battery cells of lithium ion batteries or other configurations. Furthermore, the battery module 1 and the battery pack 100 can be used for a variety of purposes, not just for automotive applications.

[0059] Furthermore, in the above embodiment, the battery pack 100 has been described as having four pouch-type battery cells 2, but the configuration of the battery pack 100 is not limited to this, and may be configured, for example, with one interposing plate 8 disposed between two pouch-type battery cells 2. Furthermore, the present invention may be applied to a case that houses a single pouch-type battery cell 2, and this case may serve as an explosion-proof member.

[0060] Furthermore, in the above embodiment, the protrusion 52 is described as having a right-angled triangular shape, but the shape of the protrusion of the present invention is not limited to this, and various shapes, such as a cone shape, can be adopted as long as the shape is capable of breaking through the exterior material 4.

[0061] REFERENCE SIGNS LIST 1 battery module 2 pouch-type battery cell 2a battery housing section 2b seal section 3 battery section 311 positive electrode plate (electrode plate) 312 negative electrode plate (electrode plate) 32 electrolyte 4 exterior material 40 opening 5 intervening plate (explosion-proof member) 51 plate section 510 ventilation path 51a one side 51b other side 52, 52A to 52F protrusions 520, 520A to 520F ventilation grooves 521, 522 divided pieces 52a side surface 52b, 52c flat surface 52d inclined surface 52e vertical surface

Claims

1. A battery module comprising: at least one pouch-type battery cell having a battery section having a plurality of stacked electrode plates and an electrolyte and an exterior material covering the battery section; and an explosion-proof member that reduces the internal pressure of the exterior material when the pouch-type battery cell expands, wherein the pouch-type battery cell has a battery housing section in which the battery section is sandwiched between the exterior material and a seal section in which the exterior material is sealed around the battery housing section, and the explosion-proof member has at least a plate section that faces the seal section of the pouch-type battery and a protrusion that protrudes from the plate section and pierces the exterior material when the pouch-type battery expands, and a ventilation groove is formed on the side of the protrusion through which gas can flow that is exhausted from an opening formed in the exterior material by the protrusion.

2. The battery module according to claim 1, wherein one end of the ventilation groove is formed in a range that reaches the plate portion.

3. The battery module according to claim 2, wherein the plate portion has an air passage formed therein that communicates with the air groove.

4. The battery module according to claim 3, wherein the ventilation path is formed by passing through the plate portion.

5. A battery module as described in claim 4, wherein the pouch-type batteries are arranged on one side and the other side of the plate portion of the explosion-proof member, the protrusions are provided on the one side and the other side of the plate portion, respectively, and the ventilation grooves of the protrusions provided on the one side and the ventilation grooves of the protrusions provided on the other side communicate with each other via the ventilation passages formed in the plate portions.

6. The battery module according to any one of claims 1 to 5, wherein the ventilation groove is formed as a dividing groove that divides the protrusion into a pair of divided pieces.

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