Battery module

Abstract

To provide a battery module capable of reducing the internal pressure of an exterior material with high certainty when a pouch-type battery formed by covering a plurality of laminated electrode plates and an electrolyte with the exterior material expands.SOLUTION: A battery module 1 includes a pouch-type battery cell 2 having a battery part 3 having a plurality of laminated positive electrode plates 311 and negative electrode plates 312 and an electrolyte 32, and an exterior material 4 covering the battery part 3, and an intervening plate 5 as an explosion-proof member. The intervening plate 5 has a plate part 51 facing the pouch type battery 2, and a projection part 52 projecting from the plate part 51 and breaking through the exterior material 4 when the pouch type battery 2 expands. In the intervening plate 5, a ventilation passage 50 through which gas discharged from an opening 40 formed in the exterior material 4 by the projection part 52 flows is formed in a part excluding a tip 52f part of the projection part 52.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[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. [Background technology]

[0002] Conventionally, battery modules having secondary battery cells each having 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 temperature of a secondary battery cell rises due to overcharging or overdischarging, for example, and the secondary battery cell becomes overheated, the electrolyte solution may evaporate and expand. Patent Documents 1 and 2 describe a configuration in which, when a secondary battery cell expands, a hole is drilled in the exterior material to reduce the internal pressure, in order to prevent the exterior material from bursting due to internal pressure even when the secondary battery cell expands.

[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 that leads to the outside of the case is formed in the center of the protrusion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-249428 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-168410 Summary of the Invention [Problem to be solved by the invention]

[0006] In a configuration in which the container of the energy storage cell is torn open with a cutting blade, as in the configuration described in Patent Document 1, 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 sufficiently reduced. Furthermore, in a configuration in which a protrusion with a through hole formed therein is provided on the case, as in the configuration described in Patent Document 2, if a portion of the exterior laminate is cut off and cut off at the periphery of the opening of the through hole in the protrusion, the cut off piece may clog the through hole, and the pressure inside the exterior laminate may not be sufficiently reduced. Furthermore, in the configuration described in Patent Document 2, the through hole opens at the tip of the protrusion, so the periphery of the opening of the through hole forms a sharp angle, which may make the tip of the protrusion easily deform and make it difficult for the tip of the protrusion to break through the exterior laminate.

[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. [Means for solving the problem]

[0008] In order to achieve the above 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 an air passage is formed in the explosion-proof member through which gas flows that is exhausted from an opening formed in the exterior material by the protrusion, and the air passage is formed in a portion excluding the tip of the protrusion. [Effects of the Invention]

[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. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an external view of a battery module according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the battery module taken along line AA in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the battery module taken along line BB in FIG. [Figure 4] FIG. 4 is a cross-sectional view that schematically shows an example of the structure of a pouch-type battery cell. [Figure 5] FIG. 5 is an exploded perspective view of the battery pack. [Figure 6] FIG. 6 is a perspective cross-sectional view showing a part of the battery pack. [Figure 7] 7(a) and (b) are perspective views showing the intervening plate. [Figure 8] FIG. 8 is an explanatory diagram showing the pouch-type battery cell in an expanded state. [Figure 9] FIG. 9 is a diagram showing the configuration of the protrusions provided on the plate portion as viewed from six directions. [Figure 10] 10(a) and 10(b) are perspective views of the protrusion and its surrounding area, including a cross section of the plate portion of the intervening plate taken along line DD in FIG. [Figure 11] FIG. 11 is a perspective view showing a protrusion according to the first modification. [Figure 12] FIG. 12 is a perspective view showing a protrusion according to the second modification. [Figure 13] FIG. 13 is a perspective view showing a protrusion according to the third modification. [Figure 14] FIG. 14 is a perspective view showing a protrusion according to the fourth modification. [Figure 15] FIG. 15 is a perspective view showing a protrusion according to the fifth modification. [Figure 16] FIG. 16 is a perspective view showing a protrusion according to the sixth modification. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment Mode] The following description will discuss embodiments of the present invention with reference to the accompanying drawings. The embodiments and modifications described below are presented as preferred examples of the present invention, and while some of them specifically exemplify various technically preferable 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 AA in Fig. 1. Fig. 3 is a cross-sectional view of the battery module 1 taken along line BB 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 multiple 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 mounted on the circuit board 141, such as ICs, resistors, and capacitors. 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 21-24. The positive electrode tabs 201 and negative electrode tabs 202 of the first to fourth pouch-type battery cells 21-24 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 electric potentials of the first to fifth bus bars 101 to 105, respectively.

[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 and 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 of 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 capable of absorbing and releasing lithium ions (Li) during manufacturing. + ) is pre-doped.

[0022] The electrolyte 32 is contained in an exterior packaging 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 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 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 4. The positive electrode tab 201 and the negative electrode tab 202 are partially exposed to the outside of the exterior packaging 4. A heat-sealing resin 400 is interposed between the exterior packaging 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 packaging 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 at 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 packaging 4, and the sealed portion 2b refers to the portion where the exterior packaging 4 seals the periphery of the battery housing section 2a. The sealed portion 2b seals the electrolyte 32 and prevents the electrolyte 32 from leaking outside the exterior packaging 4.

[0025] If the pouch-type battery cells 2 are overheated due to an increase in temperature 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 part of the battery pack 100. Figs. 7(a) and 7(b) are perspective views showing the interposing plate 5.

[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 also 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 portions 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 thereof 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 the 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 the 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 21-24, 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 accommodating section 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 accommodating section 2a in a direction parallel to the plate portion 51.

[0031] The number of protrusions 52 on the interposing 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 packaging 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 of the plate portion 51 (see Figures 7(a) and (b)), which is aligned with the center of the battery accommodating portion 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 interposing plate 5. More specifically, of the two interposing plates 5 of the battery pack 100, the spacing retaining portion 53 of one interposing 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 interposing 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 side 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 Fig. 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 111-114, 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 21-24. 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 to fourth pouch-type battery cells 21-24 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 to fourth pouch-type battery cells 21-24.

[0038] FIG. 8 is an explanatory diagram showing the state of the battery pack 100 inside the case 10 when the pouch-type battery cells 2 expand. When the pouch-type battery cells 2 expand, the protrusions 52 pierce the exterior packaging 4, releasing gas generated inside the exterior packaging 4 and reducing the internal pressure of the exterior packaging 4. The interposing plate 5 has an air passage 50 formed therein through which gas flows when it is released from the openings 40 formed in the exterior packaging 4 by the protrusions 52. The air passage 50 extends across the protrusions 52, the plate 51, and the spacing portion 53. Hereinafter, the air passage 50 in the protrusions 52 will be referred to as the protrusion air passage 520, and the air passage 50 in the plate 51 will be referred to as the plate air passage 510. The air passage 50 in the spacing portion 53 will be referred to as the spacing portion air passage 530. The protrusion ventilation passage 520, the plate ventilation passage 510, and the spacing portion ventilation passage 530 are each part of the ventilation passage 50. Next, the configuration of the protrusion 52 and its surrounding area will be described in detail with reference to Figures 9 and 10 .

[0039] 9 is a configuration diagram of the protrusions 52 provided on one surface 51a and the other surface 51b of the plate portion 51, as viewed from six directions. Figures 10(a) and 10(b) 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 retaining 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 and 52c of a right-angled triangle perpendicular to the short side direction of the plate portion 51, a slanted 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 and 52c and the vertical surface 52e are perpendicular to the one surface 51a and the other surface 51b of the plate portion 51. The slanted 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 θ1 of the inclined surface 52d relative to the one surface 51a and the other surface 51b of the plate portion 51 when viewed from the longitudinal direction of the spacing portion 53, and the inclination angle θ2 of the inclined surface 52d relative to the vertical surface 52e are each, for example, 45°. However, this is not limiting, and the inclination angles θ1 and θ2 may be, for example, between 30° and 60°. 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 tips 52f of the protrusions 52, forming openings 40 in the exterior packaging material 4 as shown in Fig. 8. The openings 40 are areas where the exterior packaging material 4 is torn by the acute-angled tips 52f of the protrusions 52.

[0042] The protrusion ventilation passage 520 is formed in the protrusion 52 except for the tip 52f. In other words, the protrusion ventilation passage 520 is not formed at the tip 52f of the protrusion 52. With this configuration, when the pouch-type battery cell 2 expands and the exterior material 4 is pressed against the tip 52f of the protrusion 52 and ruptured, and the opening 40 in the exterior material 4 passes through the tip 52f of the protrusion 52, gas inside the exterior material 4 flows into the protrusion ventilation passage 520. The gas that flows into the protrusion ventilation passage 520 flows through the plate ventilation passage 510 and the spacing portion ventilation passage 530, and then passes through the communication hole 120 in the second case member 12 and the through-hole 130 in the third case member 13 before being released to the outside of the case 10. As a result, in this embodiment, the opening 40 in the outer casing material 4 formed by the protrusion 52 is not blocked by the protrusion 52 itself, and the gas inside the outer casing material 4 can be smoothly and quickly released into the protrusion ventilation path 520.

[0043] In the present embodiment, protrusion ventilation passage 520 opens to inclined surface 52d and vertical surface 52e of protrusion 52, and is formed in a range that reaches plate portion 51. Therefore, gas inside exterior material 4 is released into protrusion ventilation passage 520 from the portions where protrusion ventilation passage 520 opens on inclined surface 52d and vertical surface 52e, and flows toward plate portion 51.

[0044] In the plate portion 51, a plate portion air passage 510 communicating with the protrusion portion air passage 520 is formed so as to penetrate the plate portion 51 in the thickness direction. In the present embodiment, the protrusion portion air passage 520 of the protrusion portion 52 provided on one surface 51a of the plate portion 51 and the protrusion portion air passage 520 of the protrusion portion 52 provided on the other surface 51b of the plate portion 51 are communicated with each other via the plate portion air passage 510 formed in the plate portion 51. However, the plate portion air passage 510 does not necessarily have to be formed so as to penetrate the plate portion 51. For example, the plate portion air passage 510 communicating with the protrusion portion air passage 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] (Effects of the embodiment) According to the embodiment described above, the protrusion ventilation passage 520 is formed in the portion of the protrusion 52 excluding the tip 52f. This prevents the protrusion 52 from blocking the opening 40 in the exterior material 4, allowing 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. Furthermore, in this embodiment, the spacing portion ventilation passage 530 that communicates with the plate ventilation passage 510 is formed in the spacing portion 53. Therefore, even if the exterior material 4 comes into contact with the plate portion 51 around the protrusion 52, as shown in FIG. 8 , gas inside the exterior material 4 can be discharged through the ventilation passage 50. Furthermore, in this embodiment, the protrusion ventilation passage 520 is formed in the portion of the protrusion 52 excluding the tip 52f, ensuring that the tip 52f of the protrusion 52 has sufficient strength to break through the exterior material 4. This makes it possible to reduce the internal pressure of the exterior material 4 with high reliability.

[0046] [Variations] Next, modified examples of the embodiment will be described with reference to Figures 11 to 16. These modified examples are obtained by changing the shape of the protrusion 52 of the interposition plate 5 according to the embodiment. Figures 11 to 16 show the protrusion and its surrounding area provided on one surface 51a of the plate portion 51, but a similar protrusion is also formed on the other surface 51b of the plate portion 51. Also, Figures 11 to 16 omit illustration of the spacing retaining portion 53.

[0047] 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.

[0048] 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 51. Like the above embodiment, the side surface 52a 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, but the positions at which the protrusion air passages are formed are different. Like the above embodiment, the plate air passage 510 formed in the plate 51 of the intervening plates 5A, 5B, 5C, and 5D communicates with the spacing portion air passage 530 formed in the spacing portion 53.

[0049] 11, protrusion air passage 520A is formed in inclined surface 52d of protrusion 52A. Protrusion air passage 520A is formed in a range from near tip 52f of protrusion 52A to plate 51, and is connected to plate air passage 510 formed to penetrate plate 51, but protrusion air passage 520A is not formed in tip 52f or vertical surface 52e of protrusion 52A.

[0050] 12, protrusion air passage 520B opens into inclined surface 52d of protrusion 52B. Protrusion air passage 520B is a through-hole that penetrates protrusion 52B in a direction perpendicular to plate 51, and opens at a location away from tip 52f of protrusion 52A, with no protrusion air passage 520B formed at tip 52f of protrusion 52B. Protrusion air passage 520B communicates with plate air passage 510 that is formed by penetrating plate 51.

[0051] 13, protrusion air passages 520C are formed in each of a pair of flat surfaces 52b, 52c of protrusion 52C. These two protrusion air passages 520C open to inclined surface 52d at the center of protrusion 52C in the height direction perpendicular to plate 51, and are formed in a range extending to plate 51 along a direction perpendicular to plate 51. Groove-shaped plate air passages 510, which are connected to protrusion air passages 520C, are formed in one surface 51a of plate 51.

[0052] 14, a groove-shaped protrusion air passage 520D is formed in one flat surface 52b of a pair of flat surfaces 52b, 52c of protrusion 52D. Protrusion air passage 520D does not open to slope 52d, and protrusion air passage 520D is not formed at tip 52f of protrusion 52D. Protrusion air passage 520D is formed in a range from the vicinity of slope 52d to plate 51, and communicates with groove-shaped plate air passage 510 formed in one surface 51a of plate 51.

[0053] FIG. 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 perpendicular to the plate 51, with a tip end surface 52g of the protrusion 52E being a flat surface inclined with respect to the central axis of the protrusion 52E. A protrusion air passage 520E is formed in a side surface 52h of the protrusion 52E parallel to the central axis of the protrusion 52E. The protrusion air passage 520E is formed in a range from the tip end surface 52g to the plate 51. A plate air passage 510 is formed in a groove shape in one surface 51a of the plate 51, and is connected to the protrusion air passage 520E. The tip end surface 52g is elliptical, with one end in the major axis direction being the tip 52f of the protrusion 52E, but the protrusion air passage 520E is not formed at the tip 52f of the protrusion 52E.

[0054] FIG. 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 direction of the plate 51. The protrusion 52F has flat surfaces 52b and 52c perpendicular to the short-side direction of the plate 51, a sloped surface 52d, and a vertical surface 52e. Two protrusion air passages 520F are formed by a notch formed in one flat surface 52b. Each protrusion air passage 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 protrusion air passages 520F forms a protrusion 522 that protrudes from the main body 521, including the right-angled triangular flat surface 52c, the sloped surface 52d, and the vertical surface 52e. The protrusion ventilation passage 520F is formed in the range from the inclined surface 52d to the plate portion 51, and communicates with a groove-shaped plate ventilation passage 510 formed in one surface 51a of the plate portion 51.

[0055] 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.

[0056] (Addendum) The present invention has been described above based on the embodiments and modifications, but 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.

[0057] In the above embodiment, the present invention has been described as being applied to a lithium ion capacitor that 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 various purposes, not just for automotive applications.

[0058] 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 it may also 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.

[0059] 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. [Explanation of symbols]

[0060] 1... Battery module 2... Pouch-type battery cell 2a... Battery storage section 2b... Sealing section 3... Battery section 311... Positive electrode plate (electrode plate) 312...Negative electrode plate (electrode plate) 32...Electrolyte solution 4...Exterior material 40...Opening 5...Intervening plate (explosion-proof member) 50...Ventilation path 51... Plate portion 510... Plate portion ventilation passage 51a...One side 51b...Other side 52, 52A to 52F... Projection 520, 520A to 520F... Projection ventilation passage 52a…side 52b,52c…plane 52d…Slope 52e…Vertical surface 52f...tip

Claims

1. at least one pouch-type battery cell having a battery section including 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; the pouch-type battery cell has a battery housing section in which the battery section is sandwiched between the exterior materials, and a seal section in which the exterior materials are sealed around the periphery of the battery housing section, the explosion-proof member has at least a plate portion facing the seal portion of the pouch-type battery, and a protrusion protruding from the plate portion and piercing the exterior material when the pouch-type battery expands; an air passage through which gas flows that is discharged from the opening formed in the exterior material by the protrusion is formed in the explosion-proof member; The ventilation path is formed in a portion excluding the tip of the protrusion. Battery module.

2. A part of the ventilation path is formed in the plate portion, and the ventilation path in the protrusion portion and the ventilation path in the plate portion are in communication with each other. The battery module according to claim 1 .

3. The air passage in the plate portion penetrates the plate portion. The battery module according to claim 2 .

4. the pouch-type battery is disposed on one surface side and the other surface side of the plate portion of the explosion-proof member, and the protrusion portion is provided on the one surface side and the other surface side of the plate portion, respectively; the air passage in the protrusion provided on the one surface side of the plate portion and the air passage in the protrusion provided on the other surface side of the plate portion are in communication with each other via the air passage in the plate portion. The battery module according to claim 3 .

5. The protrusion has a slope that is inclined relative to the plate, and the ventilation path is formed on the slope. The battery module according to claim 1 .

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