JP7677779B2 - Battery pack structure - Google Patents

Description

The present invention relates to a battery pack structure.

Patent Document 1 discloses a battery pack that includes a safety valve that is provided on the upper surface of the exterior case and breaks when the pressure inside the battery cell becomes abnormal; a cover that insulates between the bus bar and the exterior case and is provided to cover at least the upper surface of the exterior case excluding the safety valve; a heat-resistant smoke exhaust duct whose inner wall surface faces the safety valve so that the safety valve that is not covered by the cover is exposed to a smoke exhaust passage formed inside; and a cable that is placed and wired above the smoke exhaust duct and is made by bundling multiple voltage detection wires that extend from terminals electrically connected to multiple battery cells in order to obtain information regarding the states of the multiple battery cells.

JP 2012-113896 A

The structure of the battery pack described above requires the installation of a smoke exhaust duct made of a separate material from the housing to guide and exhaust the gas released from the safety valve, which increases the weight and cost of the battery pack and reduces design freedom.

The object of the present invention is to provide a battery pack structure that can suppress damage to the housing caused by heat from released gas without providing a separate component.

In one aspect of the battery pack structure of the present invention, a deflection surface is provided in an area on the inner surface of the housing that faces the gas outlet of the battery cell, and deflects the flow of gas released from the outlet out of the area.

The above battery pack structure makes it possible to prevent damage to the housing caused by heat from released gas without the need for a separate component.

1 is an overall perspective view of a battery pack according to an embodiment; FIG. 2 is an exploded perspective view of the battery pack according to the embodiment. FIG. 2 is a perspective view of a battery module according to the embodiment; 4 is a cross-sectional view taken along line IV-IV in FIG. 1, showing the deflection surface provided on the inner surface of the housing and the discharge opening of the battery cell. 5 is a view taken along line VV in FIG. 4. 5 is a cross-sectional view corresponding to FIG. 4, showing a deflection surface and an outlet according to a second embodiment. FIG. 7 is a view taken along line VII-VII in FIG. 6. FIG. 5 is a cross-sectional view corresponding to FIG. 4, showing a deflection surface and an outlet according to a third embodiment. 9 is a view taken along line IX-IX in FIG. 8 .

Below, battery pack structures according to several embodiments will be described with reference to the drawings. In each figure, FR and RR indicate the front and rear in the longitudinal direction of the vehicle, LH and RH indicate the left and right in the width direction of the vehicle, and UP and DN indicate the top and bottom in the vertical direction of the vehicle. In the following description, the front and rear in the longitudinal direction of the vehicle, and the top and bottom in the vertical direction of the vehicle will be simply referred to as "front," "rear," "upper," and "lower," respectively. Elements having the same function will be given the same reference numerals, and duplicate descriptions will be omitted.

First Embodiment
The battery pack P according to the first embodiment is a storage battery (secondary battery) mounted on an electric vehicle such as an electric vehicle (EV) or a hybrid vehicle (HV) to serve as a driving power source for the vehicle. As shown in Fig. 1, the battery pack P has a flat shape in which the overall dimension in the vertical direction of the vehicle is smaller than the dimension in the front-rear direction of the vehicle and the dimension in the vertical direction of the vehicle is smaller than the dimension in the width direction of the vehicle. The battery pack P is fixed to the lower part of the electric vehicle by fastening a plurality of mounting brackets Br provided on the outer periphery to a mounting member (not shown) on the vehicle body side using fasteners such as bolts.

As shown in Figs. 1 and 2, the battery pack P includes a plurality of battery modules M and a housing 1 that houses the battery modules M. As shown in Fig. 3, each battery module M is a modularized component in which a plurality of battery cells 2 are arranged in parallel in the vehicle width direction. The battery modules M are electrically connected to each other within the housing 1 by wiring members such as bus bars (not shown).

Each battery cell 2 is, for example, a lithium ion secondary battery, and is constructed by sealing a power generating element, in which positive and negative plates are stacked with a separator between them, in an exterior case 3 together with an electrolyte. In the battery module M, the battery cells 2 are integrated together by electrically connecting the electrode terminals of adjacent battery cells 2 with wiring members (not shown). Note that the battery cells 2 are not limited to lithium ion secondary batteries, and may be nickel-metal hydride secondary batteries, organic radical batteries, etc.

The exterior case 3 of the battery cell 2 is made of an aluminum can or the like, and has a discharge port 4 formed on its upper surface as shown in FIG. 3. The discharge port 4 is an opening through which gas is discharged when gas is generated inside the battery cell 2 due to an abnormality. The discharge port 4 is provided with a seal member (not shown) that breaks to discharge gas when the internal pressure of the battery cell 2 exceeds a predetermined pressure. The mechanism for discharging gas is not limited to a seal member, and may be an explosion-proof valve that opens to discharge gas when the internal pressure of the battery cell 2 exceeds a predetermined pressure. The shape of the discharge port 4 is not limited to the circular shape shown in the figure, and may be an elliptical shape, a polygonal shape, or the like. Furthermore, the discharge port 4 is not limited to the upper surface of the exterior case 3, and may be provided on the side or bottom surface of the exterior case 3, etc.

As shown in Figs. 1 and 2, the housing 1 is mainly composed of an upper casing _1U and a lower casing _1L . The upper casing _1U and the lower casing _1L are made of, for example, a fiber-reinforced resin. The reinforcing fibers of the fiber-reinforced resin are not particularly limited, and carbon fibers, glass fibers, boron fibers, aramid fibers, or the like can be used. The matrix resin is not particularly limited, and epoxy resin, unsaturated polyester resin, phenol resin, or the like can be used. The upper casing _1U and the lower casing _1L can be molded, for example, by a sheet molding compound (SMC) press molding method, a prepreg press molding method, or the like.

The upper casing _1U and the lower casing _1L are fastened to each other with fasteners such as bolts (not shown), forming an accommodation space H between them for the battery module M (i.e., the battery cells 2). A sealing member (not shown) made of a rubber material or the like is interposed between the peripheral edge of the upper casing _1U and the peripheral edge of the lower casing _1L to seal the accommodation space H.

2, the lower casing _1L is a box-shaped member that is generally rectangular in plan view and opens upward and has a bottom. The lower casing _1L has a flat bottom wall portion _1LB that forms the bottom of the lower casing 1L, and a peripheral wall portion _1LS that extends upward from the outer periphery of the bottom wall portion _1LB .

As shown in Fig. 2, a plurality of battery modules M are arranged in the lower casing _1L . In the illustrated example, a total of eight battery modules M are arranged in two rows in the vehicle width direction and four rows in the vehicle front-rear direction in the front portion of the lower casing _1L . In addition, in the rear portion of the lower casing _1L , the battery modules M are stacked in two layers, one above the other, and the two-layered battery modules M are arranged in two rows in the vehicle width direction and two rows in the vehicle front-rear direction, for a total of eight.

As in the illustrated example, spacers Sp may be installed in the lower casing _1L so as to divide the inside of the lower casing _1L into a plurality of regions, and one battery module M may be disposed in each divided region. In this way, the spacers Sp are interposed between adjacent battery modules M, so that the adjacent battery modules M can be kept apart from each other.

As shown in FIG. 2, the upper casing _1U is a plate-like member having a substantially rectangular shape in a plan view. In the illustrated example, the upper casing _1U has a flat wall portion _1UF formed in the front portion, and a bulging wall portion _1UB formed so as to bulge upward from the flat wall portion 1UF at a position rearward of the flat wall portion _1UF . The bulging wall portion _1UB has an upper wall portion _1UBT constituting _its upper surface, and a peripheral wall portion _1UBS extending downward from the outer peripheral edge portion of the upper wall portion _1UBT . By forming the bulging wall portion _1UB , two stacked battery modules M can be accommodated in the rear portion of the housing 1. This makes it possible to reduce the length of the entire battery pack P in the vehicle front-rear direction while making the front portion thinner. The upper casing _1U can seal the storage space H in the housing 1 by closing the opening of the lower casing _1L from above.

In this embodiment, the bottom wall _1LB and the peripheral wall _1LS of the lower casing _1L and the flat wall _1UF and the bulging wall _1UB of the upper casing _1U constitute the wall 5 that defines the storage space H in the housing 1. The inner surface 5a of the wall 5 includes a facing region R that faces the discharge port 4 of the battery cell 2. For example, as shown in Figs. 4 and 5, the facing region R is included on the lower surface of the flat wall _1UF . The facing region R is a region that directly faces the discharge port 4 and the gas discharge direction _XJ (ejection direction), and is a region that overlaps with the discharge port 4 when the inner surface 5a of the wall 5 is viewed in the gas discharge direction _XJ from inside the battery cell 2. Alternatively, the facing region R is a region where the discharge port 4 is projected in the gas discharge direction _XJ with the inner surface 5a of the wall 5 as a projection plane. The gas discharge direction _XJ is perpendicular to an opening surface 4 a defined by the outer periphery of the discharge port 4 .

A deflection surface D is provided in the opposing region R. The deflection surface D is a surface that deflects the flow of gas J (hereinafter also referred to as gas jet J) discharged from the discharge port 4 to the outside of the opposing region R. In this embodiment, a convex rib 6 that protrudes toward the discharge port 4 is formed on the inner surface 5a of the wall portion 5. In the example shown in Figures 4 and 5, the discharge port 4 opens upward, the general surface 5ag of the inner surface 5a that faces the discharge port 4 in the vertical direction extends approximately horizontally, and the convex rib 6 protrudes downward from the general surface 5ag of the inner surface 5a.

4, the protruding strip 6 has a mountain-shaped cross section, and two flat inclined surfaces S L adjacent to each other across a ridge line 6r of the protruding strip 6 form a deflection surface D. That is, in this embodiment, the deflection surface D is composed of two inclined surfaces S _L each inclined with respect to the emission direction _XJ of the gas emitted from the emission _port 4 and disposed adjacent to each other with no gap. Note that "inclined" means that the surface is neither perpendicular nor parallel to the emission direction _XJ of the gas.

As shown in Fig. 5, the ridge 6r of the protrusion 6 is arranged so as to overlap the center 4c (see Fig. 4) of the discharge port 4 when the protrusion 6 is viewed from inside the battery cell 2 in the gas discharge direction _XJ . Therefore, the flow of gas J discharged from the discharge port 4 is divided into two approximately equal flows by the apex _6T of the protrusion 6 as shown in Fig. 4. The edge of the apex _6T may be rounded. However, it is preferable that the radius of curvature is set as small as possible within the allowable range determined by the formability of the material constituting the wall portion 5, for example, 0.1 mm to 1.0 mm. By setting the radius of curvature to be smaller, the range of the stagnation region S _T described later can be made smaller.

The overall width _W6 of the ridge 6 is larger than the width _W4 (see FIG. 4) of the outlet 4 in a direction perpendicular to the extension direction of the ridge 6 and perpendicular to the gas discharge direction _XJ . Therefore, as shown in FIG. 5, the entire facing region R is composed of two inclined surfaces S _L , that is, deflection surfaces D. The intersection between the general surface 5ag of the inner surface 5a and the inclined surface S _L may be rounded. By rounding the intersection, the gas flowing from the top _6T along the inclined surface S _L toward the intersection can smoothly change the flow direction when it transfers from the inclined surface S _L to the general surface 5ag. This can reduce the heat transfer coefficient in the region near the intersection of the general surface 5ag.

In this embodiment, as shown in Figs. 2 and 3, the battery cells 2 are arranged in a row with their discharge ports 4 aligned along the vehicle width direction and housed in the housing 1. Therefore, the inner surface 5a of the wall portion 5 includes a plurality of facing regions R that respectively face the plurality of discharge ports 4 of the battery cells 2, and the plurality of facing regions R are also aligned in a row along the vehicle width direction. The protruding strip 6 is formed continuously across the plurality of facing regions R aligned in a row.

In the illustrated example, the number of ridges 6 is the same as the number of rows of the battery modules M in the vehicle front-rear direction. Specifically, as shown in Figs. 1 and 2, a total of six ridges 6 are provided, four on the flat wall portion _1UF and two on the upper wall portion _1UBT of the bulging wall portion _1UB . The ridges 6 provided on the flat wall portion _1UF each extend continuously in the vehicle width direction across the entire width of the flat wall portion _1UF in the vehicle width direction. Also, the ridges 6 provided on the upper wall portion _1UBT each extend continuously in the vehicle width direction across the entire width of the upper wall portion _1UBT in the vehicle width direction.

<Modification>
In the above embodiment, the surface of the convex strip 6 constituting the deflection surface D is composed of only two inclined surfaces S _L adjacent to each other with the ridge line 6r in between, but the configuration of the surface of the convex strip 6 is not limited to this. The surface of the convex strip 6 constituting the deflection surface D in the modified example may include other band-shaped inclined surfaces extending parallel to the extension direction of the convex strip 6 in addition to the two inclined surfaces S _L adjacent to each other with the ridge line 6r in between. The width and number of the other band-shaped inclined surfaces are not particularly limited.

In another modified example, the ridge 6r of the protrusion 6 may be disposed at a position shifted from the center 4c of the discharge port 4 when viewed from the gas discharge direction _XJ . In this case, by adjusting the position of the ridge 6r, the flow of the gas J discharged from the discharge port 4 can be diverted at a desired ratio.

In yet another modified example, the surface of the protrusion 6 may be composed of one inclined surface S _L and a surface perpendicular to the general surface 5ag (a surface parallel to the gas emission direction X _J ). In this case, the deflection surface D may be composed of only the one inclined surface S _L.

In yet another modified example, the ridges 6 may be discontinuous ridges 6 (hereinafter, discontinuous ridges) provided individually for each of the multiple opposing regions R.

The following describes the effects of the above embodiment and its modified examples (hereinafter, the first embodiment, etc.).

(1) The deflection surface D deflects the colliding gas flow. That is, the direction of the colliding gas flow is changed while retaining the velocity component (momentum component) of the flow direction before the collision (gas discharge direction _XJ ). Therefore, the flow near the surface of the gas that has collided with the deflection surface D (near the deflection surface D) contains more velocity components (momentum components) parallel to the surface than the flow near the surface of the gas that has collided with a surface perpendicular to the gas discharge direction _XJ (hereinafter, vertical surface). Therefore, the deflection surface D is less likely to form a stagnation region _ST (see FIG. 5) on the surface than a vertical surface. The stagnation region _ST is a region at or near the stagnation point, where the velocity component parallel to the surface of the gas flow is approximately zero.

According to the first embodiment and the like, a deflection surface D is provided in the facing region R facing the discharge port 4 on the inner surface 5a of the housing 1, which deflects the flow of the gas J discharged from the discharge port 4 to the outside of the facing region R. Therefore, compared to a case where the deflection surface D is not provided in the facing region R (i.e., a case where the entire facing region R is composed only of vertical surfaces, hereinafter referred to as a comparative example), a stagnation region _ST is less likely to be formed in the facing region R. Even if a stagnation region _ST is formed, the size of the range will be smaller than that of the comparative example.

In this way, according to the first embodiment and the like, it is possible to suppress the generation of the stagnation region _ST in the facing region R and reduce the maximum value of the heat transfer coefficient in the facing region R. This alleviates localized concentration of the heat load from the gas J (gas jet J) discharged from the discharge port 4, suppressing damage such as holes in the housing 1 caused by the heat from the jet gas, and ultimately reducing the possibility of fire spreading to components arranged around the battery pack P.

(2) Furthermore, according to the first embodiment and the like, there is no need to provide a smoke exhaust duct that is a separate member from the housing, as in the battery pack of Patent Document 1. This improves the design freedom of the battery pack P without increasing weight or cost.

(3) Furthermore, according to the first embodiment and the like, the deflection surface D is composed of a plurality of inclined surfaces SL each inclined with respect to the discharge direction _XJ of the gas discharged from the discharge port 4 and arranged adjacent to each other with no gaps. Alternatively, the deflection surface D is composed of a single inclined surface _SL inclined with respect to the discharge direction _XJ of the gas discharged from the discharge port 4. Therefore, since the gas _J discharged from the discharge port 4 collides obliquely with the deflection surface D, the force applied from the gas jet J to the deflection surface D in the direction perpendicular to the surface is reduced compared to the case of perpendicular collision. This makes it possible to reduce damage caused to the housing 1 by the gas jet J.

(4) According to the first embodiment and the like, the entire facing region R is formed of the deflection surface D. Therefore, the occurrence of the stagnation region _ST can be suppressed in the entire facing region R, and the maximum value of the heat transfer coefficient can be more reliably reduced. This further reduces the local concentration of the heat load.

(5) Furthermore, according to the first embodiment and the like (excluding the modified example in which the deflection surface D is formed of only one inclined surface S _L ), a convex rib 6 protruding toward the discharge port 4 is formed on the inner surface 5a of the housing 1. Two adjacent inclined surfaces S _L sandwiching the ridge line 6r of the convex rib 6 form the deflection surface D. Therefore, the flow of gas that collides with the convex rib 6 can be deflected in two directions by the two inclined surfaces S _L , thereby reducing the concentration of heat load, while improving the strength and rigidity of the wall portion 5 of the housing 1.

(6) Furthermore, according to the first embodiment, etc., the wall thickness of the wall portion 5 of the housing 1 is increased at least by the amount of the protrusion 6 formed, so that even if a large heat load is input from the gas jet J to the deflection surface D, the occurrence of holes in the housing 1 can be delayed.

(7) Furthermore, according to the first embodiment etc., the multiple battery cells 2 are arranged in a row and housed in the housing 1 with their gas release ports 4 aligned in a line, and the inner surface 5a of the housing 1 includes multiple facing regions R that respectively face the multiple release ports 4 of the multiple battery cells 2. And, according to the first embodiment etc. (excluding the discontinuous ridges), the ridges 6 are formed continuously across the multiple facing regions R. With this structure, the small number of ridges 6 can efficiently improve the strength and rigidity of the wall 5 of the housing 1 while mitigating the concentration of thermal load.

(8) In the first embodiment and the like, the inclination angle of the two inclined surfaces _SL of the convex rib 6 with respect to the gas discharge direction _XJ is not particularly limited, but the angle θ (see FIG. 4 ) between the gas discharge direction _XJ and the normal line of each inclined surface _SL of the convex rib 6 is preferably 60° or more and 75° or less. In this case, the force acting from the gas jet J on the deflection surface D in the direction perpendicular to the surface is more reliably reduced, so that the life of the housing 1 can be extended.

Next, the battery pack P according to the second and third embodiments, as well as other embodiments, will be described with reference to Figs. 6 to 9. In the description of each embodiment, only the configurations that differ from the preceding embodiment and variants (hereinafter, the preceding embodiment, etc.) will be described. Elements that have the same functions as elements already described in the preceding embodiment, etc. will be given the same reference numerals, and their description will be omitted.

Second Embodiment
6 and 7, in the battery pack P according to the second embodiment, a cone-shaped protrusion 7 protruding toward the discharge port 4 is formed on the inner surface 5a of the housing 1. A side surface _7L of the cone-shaped protrusion 7 forms a deflection surface D.

In the illustrated example, the shape of the cone-shaped convex portion 7 is a cone. As shown in Fig. 7, the apex 7v is arranged so as to overlap with the center 4c (see Fig. 6) of the discharge port 4 when the cone-shaped convex portion 7 is viewed from the gas discharge direction _XJ . Therefore, the flow of the gas J discharged from the discharge port 4 is radially and evenly diverted by the apex 7T of the cone-shaped convex portion _7. The tip of the apex _7T may be rounded. However, it is preferable that the radius of curvature is set as small as possible within the allowable range determined by the formability of the material constituting the wall portion 5, for example, 0.1 mm to 1.0 mm.

The minimum width _W7 of the cone-shaped protrusion 7 in the direction perpendicular to the gas discharge direction _XJ is larger than the maximum width _W4 of the discharge port 4 in the direction (see FIG. 6). Therefore, as shown in FIG. 7, the entire facing region R is composed of the side surface _7L of the cone-shaped protrusion 7, that is, the deflection surface D. The intersection between the side surface _7L of the cone-shaped protrusion 7 and the general surface 5ag of the inner surface 5a may be rounded. By rounding the intersection, the gas flowing from the top _7T along the side surface _7L toward the intersection can smoothly change the flow direction when transferring from the side surface _7L to the general surface 5ag. This can reduce the heat transfer coefficient in the region near the intersection of the general surface 5ag.

In this embodiment, similar to the first embodiment, the inner surface 5a of the wall portion 5 includes a plurality of facing regions R that face the plurality of discharge ports 4 of the plurality of battery cells 2. The plurality of facing regions R are arranged in a line along the vehicle width direction, and the cone-shaped protrusions 7 are formed in each of the plurality of facing regions R arranged in a line.

<Modification>
The shape of the cone-shaped convex portion 7 is not limited to a cone shape, and may be an elliptical cone shape, a pyramid shape, or a combination thereof. When the shape of the cone-shaped convex portion 7 is a cone shape or an elliptical cone shape, the side surface _7L of the cone-shaped convex portion 7 forms a deflection surface D consisting of one curved inclined surface S _L inclined with respect to the gas emission direction X _J. On the other hand, when the shape of the cone-shaped convex portion 7 is a pyramid shape, the side surface _7L of the cone-shaped convex portion 7 forms a deflection surface D consisting of a plurality of flat inclined surfaces S _L each inclined with respect to the gas emission direction X _J and arranged adjacent to each other with no gaps.

(9) The second embodiment and its modified examples (hereinafter, the second embodiment, etc.) have at least the configurations described in (1) to (4) above, and therefore can achieve the effects described in (1) to (4) above.

(10) Furthermore, according to the second embodiment and the like, the inner surface 5a of the housing 1 is formed with a pyramidal protrusion 7 protruding toward the discharge port 4, and the side surface _7L of the pyramidal protrusion 7 constitutes the deflection surface D. Therefore, since the wall thickness of the wall portion 5 of the housing 1 is increased at least by the amount of the pyramidal protrusion 7 formed, even if a large heat load is input from the gas jet J to the deflection surface D, the occurrence of holes or the like in the housing 1 can be delayed.

(11) Furthermore, according to the second embodiment and the like, since the side surface _7L of the pyramidal convex portion 7 constitutes the deflection surface D, the gas flow deflected by colliding with the deflection surface D is dispersed in more directions than when the gas flow collides with, for example, two inclined surfaces of a mountain-shaped cross-section convex stripe and is deflected in two directions. Therefore, the concentration of the heat load in the opposing region R is further alleviated.

Third Embodiment
8 and 9, in the battery pack P according to the third embodiment, the wall 5 of the housing 1 includes a general portion 5A and a thick portion 5B that is thicker than the general portion 5A. The deflection surface D is formed from a portion of the thick portion 5B that is located within the opposing region R.

In the illustrated example, the deflection surface D is configured with one inclined surface S _L inclined with respect to the discharge direction X _J of the gas discharged from the discharge port 4. In addition, the thick portion 5B configures a rib 8 protruding inwardly into the accommodation space H from the general surface 5ag of the inner surface 5a. The rib 8 may be continuously formed along the parallel direction (in the present embodiment, the vehicle width direction) of the gas discharge ports 4 arranged in a row in the housing 1. The rib 8 may be disposed so as to span a plurality of opposing regions R. This allows the strength and rigidity of the wall portion 5 of the housing 1 to be efficiently improved.

(12) The third embodiment has at least the configurations described in (1) to (4) above, and therefore can achieve the effects described in (1) to (4) above.

(13) According to the third embodiment, the wall 5 of the housing 1 includes a general portion 5A and a thick portion 5B that is thicker than the general portion 5A, and the deflection surface D is formed from a portion of the thick portion 5B that is located within the opposing region R. That is, the portion _5B1 of the thick portion 5B that forms the deflection surface D is connected to the portion _5B2 of the thick portion 5B that is located outside the opposing region R in a heat-transferable manner. Therefore, even if a thermal load is input from the gas jet J to the deflection surface D, the heat can be released from the portion _5B1 located within the opposing region R to the thick portion 5B (portion _5B2 ) located outside the opposing region R, and accordingly, the occurrence of holes in the housing 1 can be delayed.

(14) Furthermore, according to the third embodiment, the deflection surface D is formed of a single flat inclined surface _SL inclined with respect to the emission direction _XJ of the gas emitted from the emission port 4, so that the flow of gas colliding with the deflection surface D can be deflected in a specific direction. In other words, the deflection direction of the gas flow can be controlled.

(15) In the third embodiment, the inclination angle of the inclined surface _SL with respect to the gas discharge direction _XJ is not particularly limited, but the angle θ (see FIG. 8) between the gas discharge direction _XJ and the normal to the inclined surface _SL is preferably 60° or more and 75° or less. In this case, the force acting from the gas jet J on the deflection surface D in the direction perpendicular to the surface is more reliably reduced, so that the life of the housing 1 can be extended.

<Other embodiments>
In the battery pack P according to the other embodiment, a part or all of the flat inclined surface _SL constituting the deflection surface D of the preceding embodiment may be replaced with an inclined surface made of a curved surface. In this case, the surface shape of the deflection surface D can be made streamlined, and disturbance of the deflected gas jet J can be suppressed, thereby suppressing an increase in the heat transfer coefficient.

In addition, in the battery pack P according to another embodiment, the deflection surface D may be formed only in a part of the facing region R. That is, the facing region R may include a vertical surface in part. Even in this case, the occurrence of the stagnation region _ST in the facing region R can be suppressed more than in the comparative example.

In the battery pack P according to still another embodiment, the shape of the housing 1, the arrangement and number of battery modules M in the housing 1, the number of battery cells 2 per battery module M, etc. may be different from those of the preceding embodiment. The number of battery cells 2 housed in the housing 1 is not particularly limited as long as it is one or more.

Still another embodiment is a combination of two or more embodiments or modifications selected from the preceding embodiments, etc. For example, the deflection surface D of the third embodiment may be composed of the deflection surface D according to the first embodiment, etc., or the deflection surface D according to the second embodiment, etc. In the embodiment involving such a combination, it is possible to obtain the respective effects of the embodiments or modifications corresponding to the respective combined elements.

The above embodiments and variations are merely examples described to facilitate understanding of the invention. The technical scope of the invention is not limited to the specific technical matters disclosed in the above embodiments, etc., but also includes various modifications, changes, and alternative technologies that can be easily derived therefrom.

1 Housing 2 Battery cell 4 Discharge port R Opposing region 5 Wall section 5a Inner surface D Deflection surface S _L inclined surface 5A General section 5B Thick section 6 Convex strip 6r Ridge line 7 Cone-shaped convex section 7 _L side surface X _J discharge direction H Accommodation space

Claims (4)

At least one battery cell having a gas release port;
A housing that houses the at least one battery cell;
Equipped with
a deflection surface that deflects the flow of gas discharged from the discharge port to the outside of the opposing region is provided in an opposing region of the inner surface of the housing that faces the discharge port;
the housing includes a wall portion defining an accommodation space in which the at least one battery cell is accommodated;
The wall portion includes a general portion and a thick portion that is thicker than the general portion,
A battery pack structure, wherein the thick portion has a first portion located within the opposing region and constituting the deflection surface, and a second portion located outside the opposing region and connected to the first portion in a thermally conductive manner. The battery cells are arranged in a row with their gas release ports aligned in a line and housed in the housing;
the inner surface of the housing includes a plurality of facing areas respectively facing the plurality of discharge ports of the plurality of battery cells;
2. The battery pack structure of claim 1, wherein the first and second portions of the thick portion form a rib protruding from the inner surface inwardly into the storage space, the first portion being continuous across the multiple opposing regions, and the second portion being adjacent to the first portion and continuous without spanning the multiple opposing regions. The battery pack structure according to claim 1 or 2, wherein the deflection surface is composed of one inclined surface inclined with respect to the direction of gas discharged from the discharge port, or a plurality of inclined surfaces each inclined with respect to the direction of gas discharge and arranged adjacent to each other with no gaps. The battery pack structure according to any one of claims 1 to 3, wherein the entire facing region is made up of the deflection surface.

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