Battery pack

Abstract

Provided is a battery pack capable of sufficiently securing a gas retention capacity for discharged gas.　The battery pack is characterized by having: a battery group (12) which has a plurality of unit batteries (13) layered therein and has a gas discharge valve (26) on the upper surface; a fixing part (16) to which the battery group is fixed; a bus bar case (17) which is disposed on the battery group (12); a harness case (24) which is disposed on the bus bar case (17); and a bus bar case cover (18) which covers the bus bar case (17) and the harness case (25) from above. The battery pack is also characterized in that a gas discharge space (25) continuous from the gas discharge valve (26) to the bus bar case cover (18) is formed in the bus bar case (17) and the harness case (24).

Description

Assembled battery

[0001] The present invention relates to an assembled battery composed of a plurality of unit cells, and particularly to an assembled battery in which each unit cell is provided with a gas discharge valve (safety valve).

[0002] Conventionally, an assembled battery provided with a portion for temporarily retaining the gas discharged from the inside of the cell through a gas discharge valve mechanism is known.

[0003] This gas discharge mechanism is a battery component provided with a gas discharge valve designed to be opened at a predetermined pressure and discharge the gas in the battery can.

[0004] In the assembled battery of Patent Document 1, a gas discharge valve provided on the upper surface of the exterior case and breaking when the internal pressure of the unit cell becomes abnormal pressure, an insulator between the bus bar and the exterior case, and a cover provided to cover the upper surface portion of the exterior case excluding the gas discharge valve, and a smoke exhaust duct having heat resistance and an inner wall surface provided to face the gas discharge valve so that the gas discharge valve not covered by the cover is exposed to the smoke exhaust passage formed inside are provided.

[0005] Further, in order to acquire the operation state information of a plurality of unit cells, a plurality of harnesses extending from terminals electrically connected to the plurality of unit cells are bundled and placed and wired above the smoke exhaust duct.

[0006] Japanese Patent Application Laid-Open No. 2012-113896

[0007] As described above, in a lithium ion battery, for example, even when the internal pressure rises, a gas discharge valve is installed for the purpose of releasing the gas pressure and enhancing safety.

[0008] By the way, this type of lithium ion battery is used in an electric vehicle (BEV / Battery Electric Vehicle). For example, a battery for BEV has a large battery capacity per unit cell, and accordingly, the battery size becomes large, and the components (electrode group, electrolyte, active material, etc.) per unit cell also increase. Therefore, the amount of gas generated during thermal runaway of the battery tends to increase due to the increase in components. Therefore, a structure that can cope even when the amount of discharged gas increases is desired.

[0009] However, in the aforementioned Patent Document 1, a space is provided in the busbar case located above the gas discharge valve by a smoke exhaust duct to discharge the gas. However, the wire storage box (hereinafter referred to as the harness case) located above it closes off the aforementioned space in order to protect the harness from high-temperature gas. For this reason, it is difficult to increase the gas retention volume of the discharged gas.

[0010] The object of the present invention is to provide a battery pack that can secure a sufficient gas retention volume for the discharged gas.

[0011] The present invention comprises a battery group formed by stacking a plurality of unit batteries, each having a gas discharge valve on its upper surface; a fixing portion to which the battery group is fixed; a busbar case positioned above the battery group; a harness case positioned above the busbar case; and a busbar case cover that covers the busbar case and harness case from above. The busbar case and harness case are formed with a gas discharge space that allows fluidic communication from the gas discharge valve provided in the unit battery to the busbar case cover.

[0012] According to the present invention, it is possible to provide a battery pack that ensures sufficient gas retention volume for the discharged gas.

[0013] This is a cross-sectional view showing the configuration of a battery pack to explain the concept of the present invention. This is an exploded perspective view of a battery pack according to an embodiment of the present invention. This is an external top view of the battery pack shown in Figure 2. This is an external side view of the battery pack shown in Figure 2. This is a cross-sectional perspective view of the A-A section of the battery pack in Figure 3, viewed from diagonally above. This is a cross-sectional perspective view of the B-B section of the battery pack in Figure 3, viewed from diagonally above. This is a perspective view of the battery pack with the busbar case cover removed, as shown in Figure 6, viewed from diagonally above. This is a perspective view of the harness case according to an embodiment of the present invention, viewed from diagonally above. This is a cross-sectional view showing the configuration of a comparative example battery pack. This is a cross-sectional view of a first modified example of the present invention at the C-C section of Figure 3. This is a cross-sectional view of a first modified example of the present invention at the D-D section of Figure 3. This is a cross-sectional view showing the configuration of a second modified example of the present invention. This is an external perspective view showing the state in which the shielding member (harness cover) is attached to the battery pack. This is a top view of the battery pack in Figure 13, viewed from above. This is a top view of the battery pack in Figure 13, viewed from the side. This is an external perspective view showing an example of a shielding member (harness cover). This is an external perspective view showing another example of a shielding member (harness cover).

[0014] The embodiments of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the embodiments described below, and various modifications and applications are also included within the scope of the technical concept of the present invention.

[0015] First, the problems in the configuration of the comparative example will be briefly explained using Figure 9. In Figure 9, the unit battery 50 is surrounded by a side plate 51, and cell electrode terminals 52 are provided on the upper side of the unit battery 50. Busbars 53 are joined to the cell electrode terminals 52, which are electrically connected to the cell electrode terminals of adjacent unit batteries 50.

[0016] Furthermore, each busbar 53 is partitioned by a busbar case 54 to ensure insulation. Above the busbar case 54, a harness case 55 is located, and a harness 56 connected to a state detection terminal (for example, a voltage detection terminal) is housed inside.

[0017] A gas discharge valve 57 is provided on the surface of the unit battery 50 on the lower side of the harness case 55. When the internal pressure of the unit battery 50 rises, the gas discharge valve 57 ruptures due to the gas pressure, releasing gas (Gs) into the space 58 of the busbar case 54 to prevent damage to the unit battery 50. Here, the space 58 is sealed by the bottom wall of the harness case 55. Furthermore, the busbar case 54 and the harness case 55 are covered by a busbar case cover 59.

[0018] In this configuration, a space 58 is provided in the busbar case 54 located above the gas discharge valve 57 to discharge the gas (Gs). However, the space 58 is closed off in the harness case 55 located above it for the purpose of protecting the harness 56 from high-temperature gas.

[0019] Therefore, the gas storage volume for the discharged gas is insufficient, leading to problems such as increased gas temperature and gas leaks that could adversely affect surrounding electrical equipment. In addition, because the harness case 55 is placed on top of the space 58, the height of the unit battery increases by the amount of space 58 formed, creating a new problem that hinders miniaturization in the height direction.

[0020] Next, an example of the basic concept of the present invention that solves these problems will be explained with reference to Figure 1. Figure 1 shows a cross-section of the upper side (cell electrode terminal side) of a unit battery, corresponding to Figure 9. However, the present invention is not limited to this.

[0021] In Figure 1, the unit battery 50 is surrounded by side plates 51 (which constitute the fixing part as defined in the claim), and cell electrode terminals 52 are provided on the upper side of the unit battery 50. Busbars 53 are joined to the cell electrode terminals 52, which electrically connect to the cell electrode terminals of other adjacent unit batteries 50.

[0022] Furthermore, each busbar 53 is partitioned by a busbar case 60 to ensure insulation. Above the busbar case 60, a harness case 61 is positioned, and a state detection harness 56 connected to a state detection terminal (for example, a voltage detection terminal) is housed inside. The harness case 61 is made of synthetic resin and has a first harness storage section 24-1 for housing the harness connected to the cell electrode terminal 52 on one side (left side in the drawing), and a second harness storage section 24-2 for housing the harness connected to the cell electrode terminal on the other side (right side in the drawing).

[0023] A gas discharge valve 57 is provided on the surface of the unit battery 50 on the lower side of the harness case 61. A busbar case 60 located above the gas discharge valve 57 has a busbar case-side gas passage path 62 (corresponding to the gas discharge space referred to in the claims). The busbar case 60 provided between the unit battery 50 and the harness case 61 includes a main body (not shown), a mounting portion (not shown) which opens in the main body and to which the busbar 53 is attached, and a communication portion (busbar case-side gas passage path) which opens in the main body and connects the gas discharge valve 57 and the opening 72.

[0024] Furthermore, a harness case-side gas passage (corresponding to the gas discharge space as defined in the claims) 63 is formed inside the harness case 61 located above the busbar case 60, extending from the busbar case-side gas passage 62 to the busbar case cover 59. As a result, the upper surface of the gas discharge valve 57 and the lower surface of the busbar case cover 59 are fluidly connected by the gas passages 62 and 63.

[0025] The gas discharge space includes gas passage paths 62 and 63 and is formed in a straight line from above the gas discharge valve 57 to the bottom surface of the busbar case cover 59. A straight line means, for example, that a straight line can be formed from the gas discharge valve 57 to the bottom surface of the busbar case cover 59 without being obstructed by the busbar case 60 or the harness case 61.

[0026] When the internal pressure of the unit battery 50 rises, the gas discharge valve 57 is ruptured by the gas pressure, and the gas (Gs) is discharged to the busbar case cover 59 side through the busbar case side gas passage 62 formed in the busbar case 60 and the harness case side gas passage 63 formed in the harness case 61, thereby preventing damage to the unit battery 50.

[0027] As shown in the comparative example configuration in Figure 9, by not forming a space 58 in the busbar case 54, placing the harness case 61 on top of the busbar case 54, and forming a harness case-side gas passage path 63 in the harness case 61, the spatial volume of this part can be increased, and furthermore, there is no need to deliberately form a space 58 as in the comparative example configuration, so it becomes possible to reduce the size in the height direction.

[0028] Next, a specific battery pack to which the above-described concept is applied will be explained using Figures 2 to 8. Figure 2 is an exploded perspective view of the battery pack according to this embodiment, viewed from diagonally above; Figure 3 is a top view of the battery pack of Figure 2, viewed from above; Figure 4 is a side view thereof; Figure 5 is a cross-sectional perspective view of the A-A section of Figure 3, viewed from diagonally above; Figure 6 is a cross-sectional perspective view of the B-B section of Figure 5, viewed from diagonally above; Figure 7 is a cross-sectional perspective view showing the state with the busbar case cover shown in Figure 6 removed; and Figure 8 is a perspective view of the harness case removed, viewed from diagonally above.

[0029] The battery pack of this embodiment includes, as shown in Figure 2, a plurality of stacked unit batteries 13 (battery group), a pair of end plates 15 and side plates 16 surrounding these unit batteries 13 from the outside, a busbar case 17 made of synthetic resin that covers the top surface of the unit batteries 13, busbars 23 housed in the busbar case 17 and connected to the electrodes of the unit batteries 13, a harness case 24 that houses a harness for extracting detection voltage signals connected to the busbars 23 to the outside, and a busbar case cover 18 that covers the harness case 24, busbars 23 and busbar case 17 and is fixed to the top surfaces of the end plates 15 and side plates 16.

[0030] The busbar 23 has end busbars 23E at both ends, and is connected to external electrical equipment via these end busbars 23E. In addition, an insulating spacer (for example, a cell holder made of synthetic resin) 14 is placed between one unit battery 13 and an adjacent unit battery 13. Furthermore, a spacer 31 is interposed between the end plate 15 and the unit battery 13. A spacer 31 is also interposed between one unit battery 13 and an adjacent unit battery 13. An intermediate plate 13M is placed in the middle of the stacked unit batteries 13.

[0031] In Figures 2 to 5, the housing 11 constituting the battery pack 10 has a roughly elongated rectangular parallelepiped shape in which the length is greater than the width and height, and holds the battery group 12 (multiple unit batteries 13 / see Figure 5).

[0032] More specifically, the housing 11 is positioned between one unit battery 13 and an adjacent unit battery 13 and includes a plurality of cell holders 14 (see Figure 5) that hold the unit batteries 13, a pair of end plates 15, a pair of side plates 16, a busbar case 17, and a busbar case cover 18. The end plates 15 and the side plates 16 are firmly fixed together with fixing members 19 such as fixing bolts or rivets, as shown in Figure 4, and constitute the "fixing part" as defined in the claim. The unit battery 13 contains battery elements consisting of an electrolyte, a positive electrode layer, a negative electrode layer, etc. The electrolyte can be in liquid or solid form.

[0033] The cell holder 14 shown in Figure 5 is made of a resin material, such as polybutylene terephthalate (PBT). The cell holder 14 is interposed between adjacent unit batteries 13 of a plurality of unit batteries 13 stacked in the longitudinal direction, and adjacent cell holders 14 hold the unit battery 13 by sandwiching it from both sides in the thickness direction (longitudinal direction of the housing).

[0034] The pair of end plates 15 are metal plate-shaped members. These end plates 15 are positioned on both sides of the battery group 12 via a pair of spacers 31 located on both sides of the battery group 12, in the stacking direction of the multiple unit batteries 13 that make up the battery group 12. One side of the pair of end plates 15 faces the other so as to sandwich the multiple unit batteries 13 held by the cell holder 14, and a fixing portion is provided on the other side facing outward, opposite to the battery group 12.

[0035] The fixing portion 15a provided on the pair of end plates 15 is generally cylindrical in shape, as shown in Figure 3, and a part of the cylindrical side surface is provided from the outer plane of the end plate 15 toward the front of the battery pack (towards one end in the stacking direction of the unit batteries 13) or toward the rear (towards the other end in the stacking direction of the unit batteries 13). The fixing portion 15a has a bolt hole along a central axis parallel to the height direction (up and down direction) of the end plate 15.

[0036] The fixing portion 15a of this end plate 15 is a fixing member attachment portion for fixing the battery pack 10 to the mounting portion of the battery pack on an external mechanism such as a vehicle or other machine. The lower end surface of the fixing portion 15a of this end plate 15 is the support surface of the housing 11 which is supported by the external mechanism as described above.

[0037] In other words, the battery pack 10 is supported by an external mechanism at the support surface of the housing 11, which is the bottom surface of the fixing portion 15a of the end plate 15. The bolts inserted through the bolt holes of the fixing portion 15a are screwed into the female threads or nuts of the external mechanism and fastened, thereby fixing the battery pack 10 to the external mechanism. In other words, the battery pack 10 is fixed to the external mechanism by bolts and is supported by the external mechanism at least at the support surface of the housing 11, which is the lower end surface of the fixing portion 15a of the end plate 15.

[0038] The pair of side plates 16 are located on both sides in the width direction of the plurality of unit batteries 13 that constitute the battery group 12, and are arranged with respect to the unit batteries 13 via cell holders 14 (part of the cell holders 14 extends to both sides of the unit batteries 13). The width direction is, for example, the direction passing through the positive terminal and the negative terminal.

[0039] The pair of side plates 16 are generally rectangular metal members and are arranged on both sides of the housing 11 in the width direction, facing each other, sandwiching the battery group 12. The pair of side plates 16 are, for example, generally rectangular in shape, with the stacking direction of the multiple unit batteries 13 constituting the battery group 12 being the long side direction, i.e., the longitudinal direction, and the height direction of the multiple unit batteries 13 constituting the battery group 12 being the short side direction, i.e., the transverse direction.

[0040] The longitudinal ends of the pair of side plates 16 are fastened to the pair of end plates 15 by fixing members 19 such as rivets or bolts. This allows the unit batteries 13 constituting the battery group 12 to be fixed in place, or the unit batteries 13 constituting the battery group 12 to be secured (pressed) by the end plates 15 from the stacking direction. The short ends of the pair of side plates 16 are engaged with concave grooves provided in the cell holder 14. This allows the battery group 12 to be held stably and ensures insulation from the unit batteries 13.

[0041] The battery group 12 (see Figure 5) is constructed by stacking flattened rectangular unit batteries 13, that is, thin hexahedral or rectangular prism-shaped unit batteries 13 whose thickness is smaller than their width and height, in the longitudinal direction. The unit battery 13 is a prismatic lithium-ion battery and comprises a flattened rectangular battery container, an electrode group (not shown) housed inside the battery container, an electrolyte or solid electrolyte sheet, and a pair of cell electrode terminals connected to the electrode group and positioned on the upper end surface in the height direction of the battery container. Here, as described above, the pair of cell electrode terminals are the cell positive electrode terminal and the cell negative electrode terminal.

[0042] The cell electrode terminals of the unit battery 13 include a positive electrode terminal and a negative electrode terminal, both having a roughly rectangular parallelepiped shape that protrude in the height direction from the upper end surface of the battery container. The cell electrode terminals and the battery container, and the battery container and the current collector plate or electrode group are electrically insulated by a resin insulating material.

[0043] The plurality of unit cells 13 constituting the battery pack 12 are laminated such that the cell positive electrode terminals of one unit cell 13 adjacent to each other and the cell negative electrode terminals of the other unit cell 13 are alternately inverted by 180° so as to be adjacent in the stacking direction. Specifically, for example, the positive electrode terminal of one unit cell 13 is adjacent to the negative electrode terminal of the adjacent unit cell 13.

[0044] Returning to FIG. 3, the bus bar case cover 18 is a plate-like member made of a resin having electrical insulation properties such as PBT, and is disposed at the upper end of the housing 11 on the side opposite to the battery pack 12 in the height direction of the housing 11 (the vertical direction with the side on which the housing 11 is placed being the bottom) so as to cover the bus bar case 17.

[0045] The bus bar case 17 (see FIG. 2) is a plate-like member made of a resin having electrical insulation properties such as PBT and having a predetermined rigidity, and is disposed facing the upper end surface of the battery container provided with the cell positive electrode terminals and cell negative electrode terminals of the unit cell 13. Note that the predetermined rigidity means a rigidity such that the bus bar case 17 does not deform unnecessarily when attached as the assembled battery 10. That is, it is sufficient if the bus bar case 17 has sufficient rigidity.

[0046] From the upper surface of the bus bar case cover 18, a harness lead-out cylinder 20 is exposed, and various harness bundles 21a to 21c are drawn out from this portion. For example, the harness is a harness connected to a state detector installed on a bus bar or a unit cell. Connection sockets 22a to 22c are provided at the tips of the harness bundles 21a to 21c and are connected to control means (not shown).

[0047] As shown in FIGS. 6 to 7, the bus bar case 17 has an opening for exposing the upper end surfaces of the cell positive electrode terminals 27(+) and cell negative electrode terminals (-) of the plurality of unit cells 13, and partitions 32 (see FIG. 7) for insulating between the cell positive electrode terminals 27(+) and cell negative electrode terminals (-) of the unit cells 13 adjacent to each other and between the bus bars 23 adjacent to each other. The partition 32 of the bus bar case 17 is provided so as to surround the cell positive electrode terminals 27(+), cell negative electrode terminals (-) of the unit cell 13, and the periphery of the bus bar 23.

[0048] The bus bar 23 electrically and mechanically connects a plurality of unit cells 13 of the battery pack 12. The bus bar 23E is a connection conductor that electrically and mechanically connects the battery located at the outermost part of the battery pack 12 and an external terminal. Specifically, it is a bus bar. The bus bar 23 that electrically connects between adjacent unit cells 13 of the battery pack 12 is a bus bar that electrically connects between the unit cells 13, and is joined by welding to the upper end surfaces of the cell electrode terminals 27(+) and 27(-) of the plurality of unit cells 13 of the battery pack 12 exposed at the opening of the bus bar case 17.

[0049] By electrically connecting the cell positive electrode terminal 27(+) of one unit cell 13 and the cell negative electrode terminal 27(-) of the other unit cell 13 of a pair of unit cells 13 adjacent to each other in the stacking direction by the bus bar 23, a battery pack 12 in which all the unit cells 13 are electrically connected in series can be configured.

[0050] Also, near the center in the short side direction of the housing 11, a harness case 24 is arranged so as to extend along the stacking direction of the unit cells 13. The harness case 24 is arranged on the upper surface of the bus bar case 17. Further, the harness case 24 is made of a synthetic resin, and has a first harness storage portion 24-1 for storing a harness connected to one (the front side in FIG. 6) cell electrode terminal side, and a second harness storage portion 24-2 for storing a harness connected to the other (the back side in FIG. 6) cell electrode terminal side.

[0051] Also, between the first harness storage portion 24-1 and the second harness storage portion 24-2, a harness case side gas passage path (corresponding to the gas discharge space referred to in the claims) 25 is formed, and fluidly connects in a straight line the upper surface of a gas discharge valve 26 provided on the upper surface of the side where the cell electrode terminals 27(+) and 27(-) of the unit cell 13 are arranged, and the lower surface (inside) of the bus bar case cover 18.

[0052] For example, a space is formed between one side of the first harness storage section 24-1 and the other side of the second harness storage section 24-2. This space constitutes the harness case side gas passage path 25. The busbar case 17 has an opening formed opposite the gas discharge valve of the unit battery 13. Multiple openings are formed corresponding to the gas discharge valve. These openings face this space.

[0053] Furthermore, for example, the first harness storage section 24-1 and the second harness storage section 24-2 are arranged side by side when viewed in the stacking direction of the unit batteries. The first harness storage section 24-1 has a mounting surface facing the upper surface having the gas discharge valve of the cell, and a wall extending away from the battery from the mounting surface. This wall is the inner side surface (wall 1) facing the second harness storage section 24-2. From this inner side surface (wall 1), there is an outer side surface (wall 2) in a direction intersecting the stacking direction (width direction), and the harness is arranged in the space enclosed by the inner side surface (wall 1) and the outer side surface (wall 2).

[0054] Furthermore, the first harness housing section 24-1 and the second harness housing section 24-2 face each other via a gas discharge valve in the direction connecting the positive and negative electrodes. The first harness housing section 24-1 has a bottom surface, an inner side surface, and an outer side surface. The inner side surface faces the second harness housing section 24-2. The outer side surface faces the terminals. The upper surfaces of both sides have walls.

[0055] A harness case-side gas passage path 25 is formed between the first harness storage section 24-1 and the second harness storage section 24-2, which are facing each other in a direction perpendicular to the stacking direction (the direction connecting the electrode terminals).

[0056] In addition to the space between the gas discharge valve 26 of the unit battery 13 and the harness case 24, there is also the space of the gas passage path 25 on the harness case side, which is a gas retention space, so safety can be further enhanced.

[0057] Furthermore, it is preferable that the length from the gas exhaust valve 26 of the unit battery 13 to the busbar case 17 is longer than the width of the gas exhaust valve 26. This prevents the gas exhaust valve 26 from coming into contact with the busbar case 17 when it opens. Also, from the viewpoint of exhaust effect, it is preferable that the opening formed in the busbar case 17 opposite the gas exhaust valve is larger than the area of ​​the gas exhaust valve.

[0058] Figure 7 shows the busbar case cover 18 removed. As shown in Figure 7, a harness case 24 extending in the longitudinal direction of the housing 11 is located near the upper center of the housing 11. The harness case 24 comprises a longitudinally extending upper plate 24a located on the opposite side from the battery group 12, and a pair of longitudinally extending side plates 24b connected to the upper plate 24a. The space formed by the upper plate 24a and the pair of side plates 24b forms a longitudinally extending first harness storage section 24-1 and a second harness storage section 24-2.

[0059] These first and second harness storage sections 24-1 and 24-2 extend along the longitudinal direction in which the unit batteries 13 are stacked, and house a plurality of harness bundles 21a to 21c inside. In this embodiment, the harness bundles 21a to 21c are voltage detection harnesses for detecting the voltage of the unit batteries 13.

[0060] A harness case-side gas passage path 25 is formed between the first harness storage section 24-1 and the second harness storage section 24-2. This harness case-side gas passage path 25 is connected to the lower surface (inside) of the busbar case cover 18 via a through hole 30 formed in the upper plate 24a located on the upper surface of the harness case 24.

[0061] Here, the harness case-side gas passage 25 (corresponding to the harness case-side gas passage 63 in Figure 1) is fluidly connected to the busbar case-side gas passage (corresponding to the busbar case-side gas passage 62 in Figure 1) formed in the busbar case 17, although this passage is not shown. The busbar case-side passage is formed above the gas discharge valve 26 and serves as a passage for connecting the harness case-side gas passage 25 and the upper part of the gas discharge valve 26.

[0062] Furthermore, in this embodiment, the gas discharge valve 26, the busbar case side gas passage path, the harness case side gas passage path 25, and the through-hole 30 provided in the upper plate 24a are arranged in a straight line, so that the flow of the discharged gas (Gs) is not obstructed, and the gas (Gs) can be efficiently discharged when the gas discharge valve 26 breaks. Here, the busbar case side gas passage path, the harness case side gas passage path 25, and the through-hole 30 are provided corresponding to each unit battery 13. Specifically, for example, they are provided corresponding to the gas discharge valve 26 of each unit battery 13.

[0063] The gas discharge space includes gas passage paths 62 and 63 and is formed in a straight line from above the gas discharge valve 57 to the lower surface of the busbar case cover 59. A straight line means, for example, that a straight line can be formed from the gas discharge valve 57 to the lower surface of the busbar case cover 59 without being obstructed by the busbar case 60 or the harness case 61. In other words, the gas discharge space is formed in a portion where a straight line can be drawn from above the gas discharge valve to the lower surface of the busbar case cover. In this embodiment, a straight line can be formed through the through hole 30 of the harness case 24.

[0064] Figure 7 shows the configuration of the harness case 24. The harness case 24 is made of synthetic resin and comprises an upper plate 24a, a pair of side plates 24b connected to it at a 90° angle, and first and second harness storage sections 24-1 and 24-2 formed by being surrounded by these. The first and second harness storage sections 24-1 and 24-2 are made in two rows along the longitudinal direction of the harness case 24 (the stacking direction of the unit batteries 13) and coincide with the arrangement direction of the busbars 23 arranged along the longitudinal direction of the harness case 24.

[0065] The side plate 24b is positioned to correspond to the location where the cell electrode terminals of the unit battery 13 are located, and each harness bundle 21a is drawn out from the first and second harness storage sections 24-1 and 24-2, and connected to a state detection terminal 28 (see Figure 8) which is connected to the battery or busbar to detect the state of the battery. The drawn-out harness bundles 21a are held inside the harness holding section 29 (see Figure 8), and the harness holding section 29 is fixedly held to the side plate 24b. For example, the harness holding section 29 is integrally molded with the side plate 24b.

[0066] Furthermore, the harness bundle 21a and the status detection terminal 28 are electrically and mechanically connected in advance by crimping or the like. The status detection terminal 28 is electrically joined to the busbar 23 by ultrasonic welding. This ultrasonic welding is performed after the harness case 24 is attached to the upper side of the battery group 12.

[0067] A pair of first and second harness housing sections 24-1 and 24-2 are formed on the underside (unit battery side) of the upper plate 24a of the harness case 24, and a harness case-side gas passage path 25 is formed between these first and second harness housing sections 24-1 and 24-2. The first and second harness housing sections 24-1 and 24-2 are formed from the upper plate 24a and a pair of side plates 24b, and have a "U" shaped cross-section with an open side facing the unit battery 13. They have an inner wall on the side closer to the gas passage path 25 and an outer wall on the side further away.

[0068] Therefore, the side plates 24b forming the first and second harness housing sections 24-1 and 24-2 create a gas passage path 25 on the harness case side. Although the unit battery side of the first and second harness housing sections 24-1 and 24-2 is open in a "U" shape as described above, this open portion can also be closed as shown in Figure 1.

[0069] Thus, the harness case-side gas passage path 25 formed in the harness case 24 is formed between a first harness storage section 24-1, which houses a harness bundle 21a connected to one of the pair of cell electrode terminals 27 of the stacked unit battery 13, and a second harness storage section 24-2, which houses a harness bundle 21a connected to the other of the pair of cell electrode terminals 27.

[0070] Furthermore, the first harness storage section 24-1 and the second harness storage section 24-2 are formed from an upper plate 24a that forms the harness case 24 and a pair of side plates 24b that are connected to the upper plate 24a at a predetermined angle (90° in this case). The harness case-side gas passage path 25 formed in the harness case 24 includes the side plates 24b that form the first harness storage section 24-1 and the second harness storage section 24-2, and are adjacent to each other. Alternatively, the harness case-side gas passage path 25 is formed between the first harness storage section 24-1 and the second harness storage section 24-2 when they are arranged on both sides.

[0071] Furthermore, the harness case-side gas passage 25 formed in the harness case 24 is fluidly connected to the lower surface (inside) of the busbar case cover 18 by a through hole 30 formed in the upper plate 24a. Alternatively, the through hole 30 separates the harness case-side gas passage 25 from the lower surface of the busbar case cover 18.

[0072] The harness case-side gas passage paths 25 are provided corresponding to each of the unit batteries 13 and are fluidly connected to the lower surface (inside) of the busbar case cover 18 by through holes 30 provided in the upper plate 24a.

[0073] By combining such a harness case 24 with the battery group 12, the configuration shown in Figure 7 is obtained. With this configuration, when the gas discharge valve 26 of the unit battery 13 ruptures, the internal gas (Gs) is ejected from the opening of the gas discharge valve 26 and simultaneously travels straight through the busbar case-side gas passage path formed in the busbar case 17 and the harness case-side gas passage path 25 formed in the harness case 24, and is ejected to the lower surface of the busbar case cover 18 through the through hole 30 formed in the upper plate 24a of the harness case 24.

[0074] Therefore, by providing the harness case-side gas passage path 25, sufficient gas retention volume for the discharged gas can be secured, and since a space is formed in the harness case 24 itself by the gas passage hole, there is no need to form an extra space as in the comparative example, making it possible to reduce the size in the height direction.

[0075] As described above, the present invention comprises a battery group formed by stacking a plurality of unit batteries having a gas discharge valve on its upper surface, a fixing part to which the battery group is fixed, a busbar case disposed on top of the battery group, a harness case disposed on top of the busbar case, and a busbar case cover that covers the busbar case and harness case from above, wherein the busbar case and harness case have gas discharge spaces formed therein that are fluidly connected from the gas discharge valve to the busbar case cover.

[0076] According to this, sufficient gas retention volume for the discharged gas can be secured, and it is also possible to reduce the height of the unit battery.

[0077] Furthermore, the battery pack is characterized in that it comprises, for example, a plurality of unit batteries each equipped with a pair of cell electrode terminals provided on one end and a gas discharge valve provided between the cell electrode terminals, and a fixing part for fixing a battery group in which the unit batteries are stacked, the cell electrode terminals of adjacent unit batteries are electrically connected by busbars, each busbar is electrically insulated by a busbar case, a harness case extending along the stacking direction of the unit batteries is arranged on the opposite side of the busbar case from the cell electrode terminals, and the busbar case and harness case are covered by a busbar case cover, and a gas discharge space is formed in the busbar case and harness case that is fluidly communicating from above the gas discharge valve provided on the unit battery to the lower surface of the busbar case cover.

[0078] This ensures sufficient gas retention volume for the discharged gas and allows for miniaturization of the unit battery in the height direction. Since the harness is not located in the gas discharge space, the impact of gas discharge can be suppressed.

[0079] Furthermore, in the above-described battery pack, for example, the gas discharge space is characterized by being formed in a straight line from above the gas discharge valve to the lower surface of the busbar case cover. This makes it even more suitable for containing gas when discharging it.

[0080] Furthermore, in the above-described battery pack, for example, the gas exhaust space formed in the harness case is characterized by being formed between a first harness storage section, which houses a harness connected to one of the pair of cell electrode terminals of the stacked unit batteries, and a second harness storage section, which houses a harness connected to the other of the pair of cell electrode terminals. This further suppresses the harness from being affected by exhaust gases.

[0081] Furthermore, in the above-described battery pack, for example, the first harness housing and the second harness housing are formed from an upper plate forming the harness case and a pair of side plates connected to the upper plate at a predetermined angle, and the gas exhaust space formed in the harness case is characterized in that it includes the side plates that form the first harness housing and the second harness housing and are adjacent to each other. This further suppresses the harness from being affected by exhaust gas.

[0082] Next, modified examples of the present invention will be described using Figures 10 to 12. Figures 10 to 11 show the first modified example, and Figure 12 shows the second modified example.

[0083] First, I will explain the first modification, which can be applied when a large-capacity battery is installed. When the battery capacity increases, the exhaust gas volume also increases, and it is required that the design be able to handle this, or that the structure has high strength. For this reason, it is characterized by the following configuration.

[0084] Figure 10 shows a cross-section corresponding to the C-C cross-section in Figure 3. Note that the C-C cross-section is a cross-section near the center when viewed in the longitudinal direction of the battery pack 10. As shown in Figure 10, the height (H) of the harness case 61 toward the busbar case cover 59 is set low.

[0085] Therefore, a gap 64 of length (L) is formed between the inner surface of the busbar case cover 59 and the upper end surface of the harness case 61. This gap 64 is formed over a predetermined range when viewed in the longitudinal direction of the battery pack 10. As a result, the diffusion of gas discharged from the gas discharge valve 57 can be improved by the gap 64.

[0086] On the other hand, Figure 11 shows a cross-section corresponding to the D-D cross-section in Figure 3. Note that the D-D cross-section is a cross-section near the end when viewed in the longitudinal direction of the battery pack 10. As shown in Figure 11, the height (H) of the harness case 61 toward the busbar case cover 59 is set high, and in this embodiment, the inner surface of the busbar case cover 59 and the upper end surface of the harness case 61 are in contact.

[0087] The area where the inner surface of the busbar case cover 59 and the upper end surface of the harness case 61 come into contact is formed over a predetermined range from both end surfaces when viewed in the longitudinal direction of the battery pack 10. Therefore, since the busbar case cover 59 is supported by the harness case 61, the structural strength of the battery pack 10 can be ensured.

[0088] Therefore, even when a space is formed near the center of the battery pack 10 by a gap 64 to enhance diffusion, the structural strength of the battery pack 10 can be improved.

[0089] Thus, in the first modified example, a predetermined gap is formed between the first harness storage section 24-1 (see Figure 1) and the second harness storage section 24-2 (see Figure 1) and the busbar case cover 59 near the center of the stacked battery group as viewed in the stacking direction. Furthermore, the first harness storage section 24-1 (see Figure 1) and the second harness storage section 24-2 (see Figure 1) and the busbar case cover 59 are in contact with each other near the ends of the stacked battery group as viewed in the stacking direction.

[0090] Next, we will explain the second modification. As mentioned earlier, increasing the battery capacity results in a larger volume of exhaust gas, so it is necessary to be able to adequately retain the exhaust gas. For this reason, the second modification is characterized by the following configuration.

[0091] As shown in Figure 12, a bulge 65 is formed on the busbar case cover 59 located on the upper surface of the harness case 61, extending outward from the harness case 61. This bulge 65 secures a large space for the gas discharged from the gas discharge valve 57 to accumulate, and also allows for the provision of a compact battery pack overall.

[0092] The area where the bulge 65 is formed extends over the harness case area 66 where the harness case 61 exists, when viewed in a direction along the direction connecting the two cell electrode terminals 52 of the unit battery 50. Furthermore, the cross-sectional shape of the bulge 65 is formed in an arc shape when viewed in a direction perpendicular to the direction connecting the two cell electrode terminals 52 of the unit battery (towards the unit battery), but it is not limited to this and may be rectangular in shape.

[0093] Thus, in the second modified example, the busbar case cover 59 facing the gas discharge space formed between the first harness storage section 24-1 (see Figure 1) and the second harness storage section 24-2 (see Figure 1) is characterized in that a bulge 65 extending away from the harness case is formed thereon.

[0094] Next, we will explain the configuration of the harness case used in the present invention. This will be explained using Figures 13 to 17. The reference numbers used are those corresponding to those in Figure 1. Therefore, explanations for the same reference numbers will be omitted, although explanations may be provided as needed.

[0095] First, in Figures 13 to 15, the battery casing 50A, which constitutes the unit battery 50, houses the charge / discharge element and the electrolyte. The battery casing 50A is sealed by the battery cover 50B, and the cell electrode terminals 52 are attached to the top surface (one side) 50C of the battery cover. Here, the battery casing 50A and the battery cover 50B constitute the outer casing of the unit battery 50.

[0096] Furthermore, a gas release valve (hereinafter referred to as a cleavage valve) 57 is formed near the center of the battery cover 50B. A busbar case cover (hereinafter referred to as a covering member, but both terms are used for clarity) 59 is provided to cover the busbar 53 and the harness case 61.

[0097] A busbar 53 is fixed to the cell electrode terminal 52 by welding or other means. A voltage detection terminal 77 is fixed to the upper surface of the busbar 53, and a harness (hereinafter referred to as a wire, but both terms are used for clarity) 56 is connected to the voltage detection terminal 77. The voltage detection terminal 77 detects the voltage of each unit battery 50, and each wire (harness) 56 is housed in a harness case (hereinafter referred to as a shielding member, but both terms are used for clarity) 61. As shown in Figure 14, the wire (harness) 56 consists of multiple wires extending from each voltage detection terminal 77, and at least some of the wires (harnesses) 56 extend across multiple unit batteries 50.

[0098] Similar to Figure 1, a pair of shielding members (harness cases) 61 are provided so as to sandwich the cleavage valve 57. The shielding member (harness case) 61 has an "L" shaped cross-section in the direction perpendicular to the longitudinal direction, and consists of a mounting portion 70 on which the electric wire (harness) 56 is placed, and a wall portion 71 extending from the cleavage valve 57 toward the covering member (busbar case cover) 59. Therefore, the pair of wall portions 71 are arranged so as to sandwich the cleavage valve 57. Furthermore, these wall portions 71 extend until they are close to the covering member (busbar case cover) 59.

[0099] Furthermore, an opening 72 is formed in the portion of the shielding member (harness case) 61 that faces the cleavage valve 57, which conforms to the shape of the cleavage valve 57, thereby allowing gas from the cleavage valve 57 to flow toward the covering member 59.

[0100] Figure 16 is a perspective view showing the configuration of the shielding member (harness case) 61. As mentioned earlier, the pair of shielding members (harness cases) 61 consist of a mounting portion 70 and a wall portion 71, and have an "L" shaped cross-section. The pair of mounting portions 70 are connected to each other by a plurality of bridging portions 73. An opening 72 is formed between adjacent bridging portions 73.

[0101] The openings 72 formed in adjacent bridge sections 73 are shaped to correspond to the shape of the cleavage valve 57. Therefore, the gas discharged from the cleavage valve 57 passes through these openings 72 and reaches the covering member (bus bar case cover) 59.

[0102] Figure 17 is a perspective view showing another configuration of the shielding member (harness case) 61. The pair of shielding members (harness cases) 61 have a cylindrical shape with a rectangular passage. The lower and upper sides of the pair of cylindrical parts 74 are connected to each other by a plurality of bridging parts 75. An opening 72 is formed between adjacent bridging parts 75.

[0103] This opening 72 is shaped to correspond to the shape of the cleavage valve 57. Therefore, the gas discharged from the cleavage valve 57 passes through this opening 72 and reaches the covering member (bus bar case cover) 59.

[0104] Here, a storage space 76 for the electric wire (harness) 56 is formed in the cylindrical portion 74, and in order to form this storage space 76, the cylindrical portion 74 has a mounting portion 70 and a wall portion 71 as explained in Figure 16.

[0105] The main features of the embodiments shown in Figures 13 to 17 above are described below. [Feature 1] The battery pack 10 includes a charge / discharge element and an electrolyte solution, an outer casing (battery can 50A and battery cover 50B) containing the charge / discharge element and the electrolyte solution, and a cleavage valve 57 provided on one surface 50C of the outer casing (battery cover 50B) that cleaves open by a predetermined internal pressure, and comprises a plurality of unit batteries 50 whose respective surfaces 50C are adjacent to each other along the stacking direction.

[0106] Furthermore, the unit battery 50 is provided on one side 50C of the battery cover 50B and is equipped with a wire (harness) 56 electrically connected to the unit battery 50. Here, the wire (harness) 56 refers to a bundle of wires. In addition, a shielding member (harness case) 61 is provided between the multiple unit batteries 50 and the wire (harness) 56, shielding the opening valve 57 and the wire (harness) 56.

[0107] Furthermore, the shielding member (harness case) 56 is integrally formed with a mounting portion 70 on which the electric wire (harness) 56 is placed, an opening 72 adjacent to the mounting portion 70 and facing the cleavage valve 57, and a wall portion 71 formed integrally with the mounting portion 70 and extending from the edge of the opening 72 in a direction away from the cleavage valve 13.

[0108] Furthermore, it has a space 63 adjacent to the wall portion 71, facing the cleavage valve 57 through the opening 72. In addition, the electric wire (harness) 56 is separated from the space 63 via the mounting portion 70 and the wall portion 71.

[0109] This simple configuration makes it possible to suppress or prevent adverse effects on the battery pack (e.g., heat damage) caused by the gas discharged from the cleavage valve 57.

[0110] In particular, in this embodiment, the cleavage valve 57 of the unit battery 50 and the space 63 of the shielding member (harness case) 61 are formed facing each other. Therefore, the space 63 of the shielding member (harness case) 61 can store the gas discharged from the cleavage valve 57.

[0111] Furthermore, the electric wire (harness) 56 is separated from the space 63 via the mounting portion 70 and the wall portion 33. Therefore, the mounting portion 70 and the wall portion 71 of the shielding member (harness case) 61 can prevent the gas discharged from the cleavage valve 57 from coming into contact with the electric wire (harness) 56.

[0112] Furthermore, the mounting portion 70 and the wall portion 71 are integrally formed from, for example, synthetic resin. With this configuration in which the mounting portion 70 and the wall portion 71 are integrally formed, a sufficient space can be provided to store the gas discharged from the cleavage valve 57 of the unit battery 50 with a simple configuration.

[0113] This makes it possible to suppress or prevent adverse effects (e.g., heat damage, etc.) on the components of the battery pack by the gas discharged from the rupture valve 57 when the rupture valve 57 of the unit battery 50 opens. In other words, with a simple configuration, adverse effects (e.g., heat damage, etc.) on the electric wires (harness) 56 and shielding members (harness cases) 61 by the gas discharged from the rupture valve 57 can be suppressed or prevented.

[0114] Furthermore, in the mounting portion 70 of the shielding member (harness case) 61, the area where gas is stored in the area where the electric wires (harness) 56 are arranged and in the space portion 63 of the shielding member (harness case) 61 are determined to be in approximately the same position when using one side (top surface) 50C of the multiple unit batteries 50 as a reference.

[0115] Therefore, even if a gas storage space 63 is provided in the shielding member (harness case) 61, the size (height) of the battery pack can be suppressed when viewed from a direction away from one side (top surface) 50C of the multiple unit batteries 50.

[0116] Therefore, without relatively increasing the size of the battery pack, it is possible to provide sufficient space to store the gas discharged from the rupture valve 13 of the battery. In other words, without relatively increasing the size of the battery pack, it is possible to suppress or prevent adverse effects (e.g., heat damage, etc.) on the electrical wire (harness) 56 caused by the gas discharged from the rupture valve 57 when the rupture valve 57 of the unit battery 50 ruptures.

[0117] [Feature 2] Furthermore, the mounting portion 70 and wall portion 71 of the shielding member (harness case) 61 are formed continuously across multiple unit batteries 50 along the stacking direction of the unit batteries 50, and the electric wire (harness) 56 is arranged across multiple unit batteries 50 along the stacking direction.

[0118] As a result, even if the battery pack is configured in which the wires (harness) 56 are arranged across multiple unit batteries 50, adverse effects (such as heat damage) on the wires (harness) 56 and shielding member (harness case) 61 by the gas discharged from the rupture valve 57 can be suppressed or prevented.

[0119] [Feature 3] Furthermore, the wall portions 71 of the shielding member (harness case) 61 are formed in pairs with the opening valve 57 in between, and the electric wires (harness) 56 are arranged in a first arrangement space formed by one wall portion 71 and the mounting portion 70, and in a second arrangement space formed by the other wall portion 71 and the mounting portion 70.

[0120] As a result, even if the battery pack has a configuration in which multiple wires (harnesses) 56 are arranged separately, adverse effects (such as heat damage) on the wires (harnesses) 56 and shielding member (harness case) 61 by the gas discharged from the rupture valve 57 can be suppressed or prevented.

[0121] [Feature 4] Furthermore, the mounting portion 70 of the shielding member (harness case) 61 is formed continuously along the stacking direction of the unit batteries 50, spanning multiple unit batteries 50, and multiple openings 72 are formed along the mounting portion 70, with each opening 72 facing the opening valve 57 of a different unit battery 50.

[0122] This makes it possible to suppress or prevent the gas discharged from the rupture valve 57 of the first unit battery 50 from moving toward the second unit battery 50, compared to the case where the rupture valve 57 of the first unit battery 50 and the rupture valve 57 of the second unit battery 50, which are adjacent along the stacking direction, correspond to a single common opening. Therefore, adverse effects on the second unit battery 50 (e.g., thermal damage) caused by the rupture of the rupture valve 57 of the first unit battery 50 can be suppressed or prevented.

[0123] [Feature 5] Furthermore, the space 63 formed by the wall portion 71 of the shielding member (harness case) 61 is formed along the stacking direction of the unit batteries 50 and spans multiple unit batteries 50.

[0124] This allows the gas discharged from the cleavage valve 57 of the first unit battery 50 to be moved to the space 63 on the side of the second unit battery 50 adjacent to the first unit battery 50, if the amount of gas discharged from the cleavage valve 57 of the first unit battery 50 is relatively large. Therefore, it is possible to suppress or prevent the gas discharged from the cleavage valve 57 of the first unit battery 50 from adversely affecting the second unit battery 50, while also suppressing or preventing it from adversely affecting the first unit battery 50.

[0125] [Feature 6] Furthermore, the opening 72 formed by the bridging portions 73 and 75 of the shielding member (harness case) 61 is formed to face the entire area of ​​the cleavage valve 13 along the direction in which the shielding member (harness case) 61 and the unit battery 50 face each other.

[0126] This allows the gas discharged from the cleavage valve 57 of the unit battery 50 to be moved to the space 63. Therefore, it is possible to suppress or prevent the gas discharged from the cleavage valve 57 of the unit battery 50 from affecting the unit battery 50.

[0127] [Feature 7] Furthermore, the shielding member (harness case) 61 and the multiple unit batteries 50 are separated from each other, and the length of the space 63 along the direction in which the shielding member (harness case) 61 and the unit batteries 50 face each other (the length of the space 63 when the unit batteries are viewed from the side) is set to be longer than the length from the opening 72 to the cleavage valve 57 along the direction in which the shielding member (harness case) 61 and the unit batteries 50 face each other (the length between the opening 72 and the cleavage valve 57 when the unit batteries are viewed from the side).

[0128] According to this, the gas discharged from the cleavage valve 57 of the unit battery 50 can be accumulated in relatively larger quantities in the space 63 of the shielding member (harness case) 61 than in the area between the unit battery 50 and the shielding member (harness case) 61. Therefore, it is possible to suppress or prevent the gas discharged from the cleavage valve 57 of the unit battery 50 from affecting the unit battery 50.

[0129] [Feature 8] The shielding member (harness case) 61 and the multiple unit batteries 50 are separated from each other, and the area of ​​the region where the cleavage valve 57 and the opening 72 overlap each other (the area of ​​the part of the opening 72 that is in relative position to the cleavage valve 57 when the unit battery is viewed from above and below) is formed to be wider than the area of ​​the region surrounding the gap between the cleavage valve 57 and the opening 72 (the gap between the opening 72 and the cleavage valve 57 when the unit battery is viewed from the side).

[0130] This allows the gas discharged from the cleavage valve 57 of the unit battery 50 to be efficiently moved away from the battery 10, in the direction from the cleavage valve 57 towards the opening 72, rather than through the gap between the cleavage valve 57 and the opening 72 of the shielding member (harness case) 61.

[0131] [Feature 9] The electric wire (harness) 56 is a bundle of multiple electric wires, and at least some of the electric wires (harness) 56 are configured to span multiple unit batteries 50 in the stacking direction of the unit batteries 50.

[0132] This makes it possible to suppress or prevent adverse effects (such as heat damage) on the wires (harnesses) 56 caused by gas discharged from the rupture valve 57, even if some of the wires (harnesses) 56 are arranged to span multiple unit batteries 50.

[0133] [Feature 10] The shielding member (harness case) 61 is made of a heat-resistant material. Therefore, even if the temperature of the gas discharged from the cleavage valve 57 of the unit battery 50 is high, adverse effects on the electric wire (harness) 56 (e.g., heat damage) can be suppressed or prevented.

[0134] [Feature 11] The device further includes a busbar 53 that connects adjacent unit batteries 50, and a busbar case 60 provided between the unit batteries 50 and a shielding member (harness case) 61. The busbar case 60 includes a main body, an attachment portion which is open in the main body and to which the busbar 53 is attached, and a communication portion which is open in the main body and connects the cleavage valve 57 and the opening 72.

[0135] According to this, even with a configuration that includes a busbar case 60, it is possible to suppress or prevent the gas discharged from the cleavage valve 57 of the unit battery 50 from adversely affecting the unit battery 10.

[0136] [Feature 12] Multiple electric wires (harnesses) 56 and busbars 53 are provided, and each electric wire (harness) 56 is electrically connected to a different busbar 53, for example, via a crimp terminal.

[0137] [Feature 13] In the direction in which the shielding member (harness case) 61 and the unit battery 50 face each other, the covering member (busbar case cover) 59 is provided, which is further away from the unit battery 50 than the shielding member (harness case) 61 and covers the space 63 of the shielding member (harness case) 61.

[0138] According to this, it is possible to suppress or prevent the gas discharged from the cleavage valve 57 of the unit battery 50 from leaking to the outside of the battery pack.

[0139] The features of the embodiments shown in Figures 13 to 17 above can be summarized as follows.

[0140] Feature 1 is a battery pack comprising: a charge / discharge element, an electrolyte, an outer casing containing the charge / discharge element and the electrolyte, a cleavage valve provided on one surface of the outer casing that cleaves when subjected to a predetermined internal pressure, a plurality of batteries, each with one surface adjacent to the other along the stacking direction, electric wires provided on the side of the one surface and electrically connected to the batteries, and a shielding member provided between the plurality of batteries and the electric wires that shields the cleavage valve and the electric wires, wherein the shielding member comprises: an arrangement portion on which the electric wires are arranged, an opening adjacent to the arrangement portion and facing the cleavage valve, a wall portion formed integrally with the arrangement portion and extending from the edge of the opening in a direction away from the cleavage valve, and a space portion facing the cleavage valve through the opening and adjacent to the wall portion, the electric wires being separated from the space portion via the arrangement portion and the wall portion.

[0141] Feature 2 is the battery pack according to Feature 1, wherein the arrangement portion and the wall portion are formed continuously across a plurality of the batteries along the stacking direction, and the electric wires are arranged across a plurality of the batteries along the stacking direction.

[0142] Feature 3 is the battery pack according to Feature 1, wherein the wall portions are formed in pairs, and the electric wires are arranged in a first arrangement space formed by one of the wall portions and the arrangement portion, and in a second arrangement space formed by the other wall portion and the arrangement portion.

[0143] Feature 4 is the battery pack according to Feature 1, wherein the arrangement portion is formed continuously across a plurality of the batteries along the stacking direction, a plurality of openings are formed in the arrangement portion, and each of the openings faces the opening valve of a different battery.

[0144] Feature 5 is the battery pack described in Feature 1, wherein the space spans multiple batteries along the stacking direction.

[0145] Feature 6 is the battery pack according to Feature 1, wherein the opening faces the entire area of ​​the cleavage valve in the direction in which the shielding member and the battery face each other.

[0146] Feature 7 is the battery pack according to Feature 1, wherein the shielding member and the plurality of batteries are spaced apart from each other, and the length of the space along the direction in which the shielding member and the batteries face each other is longer than the length from the opening to the cleavage valve along the direction in which the shielding member and the batteries face each other.

[0147] Feature 8 is the battery pack described in Feature 1, wherein the shielding member and the battery are separated from each other, and the area of ​​the region where the cleavage valve and the opening overlap each other is larger than the area of ​​the region surrounding the gap between the cleavage valve and the opening.

[0148] Feature 9 is the battery pack described in Feature 1, wherein multiple wires are provided, and at least some of the wires span multiple batteries.

[0149] Feature 10 is the battery pack described in Feature 1, wherein the shielding member is heat resistant.

[0150] Feature 11 is a battery pack according to Feature 1, further comprising a busbar connected to one of the batteries and another of the batteries, and a busbar case provided between a plurality of the batteries and the shielding member, wherein the busbar case includes a main body, a mounting portion opening in the main body and to which the busbar is attached, and a communication portion opening in the main body and connecting the cleavage valve and the opening.

[0151] Feature 12 is the battery pack described in Feature 11, wherein multiple electric wires and busbars are provided, and each electric wire is electrically connected to a different busbar.

[0152] Feature 13 is the battery pack according to Feature 1, further comprising a covering member that, in the direction in which the shielding member and the battery face each other, is further away from the battery than the shielding member and covers the space of the shielding member.

[0153] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add a configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with other configurations.

[0154] 10...Battery pack, 11...Housing, 12...Battery group, 13...Unit battery, 14...Cell holder, 15...End plate, 16...Side plate, 17...Busbar case, 18...Busbar case cover, 20...Harness outlet tube, 23...Busbar, 24...Harness case, 24a...Top plate, 24b...Side plate, 24-1, 24-2...Harness storage section, 25...Gas passage path on harness case side, 26...Gas discharge valve, 28...Status detection terminal, 29...Harness holder, 30...Through hole.

Claims

1. A battery pack comprising: a battery group comprising a plurality of unit batteries having a gas discharge valve and cell electrode terminals stacked on top of each other; a fixing part to which the battery group is fixed; a busbar case disposed on the side of the battery group having the cell electrode terminals; a harness case disposed on the opposite side of the busbar case from the unit battery side of the busbar case; and a busbar case cover disposed on the opposite side of the harness case from the busbar case side and covering the busbar case and the harness case, wherein the busbar case and the harness case have a gas discharge space that is fluidly connected from the gas discharge valve provided on the unit battery to the busbar case cover.

2. A battery pack comprising a plurality of unit batteries, each having a pair of cell electrode terminals provided at one end and a gas discharge valve provided between the cell electrode terminals, and a fixing portion for fixing a battery group in which the unit batteries are stacked, wherein the cell electrode terminals of adjacent unit batteries are electrically connected by busbars, each busbar is electrically insulated by a busbar case, a harness case extending along the stacking direction of the unit batteries is arranged on the opposite side of the busbar case from the cell electrode terminals, and a busbar case cover covering the busbar case and the harness case, wherein a gas discharge space is formed in the busbar case and the harness case, which is fluidly communicating from above the gas discharge valve provided on the unit battery to the lower surface of the busbar case cover.

3. A battery pack according to claim 1 or claim 2, characterized in that the gas discharge space has a portion formed in which a straight line can be drawn from above the gas discharge valve to the lower surface of the busbar case cover.

4. The battery pack according to claim 3, wherein the gas discharge space formed in the harness case is formed between a first harness storage section, which houses a harness connected to one of the pair of cell electrode terminals of the stacked unit batteries, and a second harness storage section, which houses a harness connected to the other of the pair of cell electrode terminals.

5. A battery pack according to claim 4, wherein the first harness housing and the second harness housing each have an upper plate forming the harness case and a pair of side plates connected to the upper plate at a predetermined angle, and the first harness housing and the second harness housing each have adjacent side plates that form the gas discharge space formed in the harness case.

6. A battery pack according to claim 5, characterized in that the gas discharge space formed in the harness case is connected to the lower surface of the busbar case cover by a through hole formed in the upper plate.

7. A battery pack according to claim 4, characterized in that a predetermined gap is formed between the first harness housing and the second harness housing and the busbar case cover near the center of the stacked battery group as viewed in the stacking direction, and the first harness housing and the second harness housing and the busbar case cover are in contact with each other near the ends of the stacked battery group as viewed in the stacking direction.

8. A battery pack according to claim 4, characterized in that the busbar case cover facing the gas discharge space formed between the first harness storage portion and the second harness storage portion has a bulge formed thereon that extends away from the harness case.

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