Battery pack case and battery pack

Abstract

A battery pack case, according to the present invention, is used for the formation of a battery pack mounted in an electric vehicle, the battery pack case comprising: a tray that is attached to the body of the electric vehicle; a battery holding member that is attached to at least a portion on the tray and that holds the battery; and a cover that covers the tray and the battery holding member, wherein at least two from among the tray, the battery holding member, and the cover contain fiber-reinforced plastic.

Description

[Technical field]

[0001] The present disclosure relates to a battery pack case and a battery pack, and more particularly to a battery pack case used to form a battery pack to be mounted on an electric vehicle, and a battery pack to be mounted on an electric vehicle. [Background technology]

[0002] 2. Description of the Related Art In recent years, various studies have been conducted on battery pack cases used to form battery packs to be mounted on electric vehicles, and on battery packs to be mounted on electric vehicles.

[0003] For example, in the following Patent Document 1, A battery pack case assembly for an electric vehicle including a case body in which a battery pack is housed and a cover assembled to the case body, The case body is made of a plastic composite material that uses long fibers or a mixture of long fibers and continuous fibers as reinforcing fibers in a plastic base material. A battery pack case assembly for an electric vehicle is disclosed, in which separate reinforcing members made of a plastic composite material in which long fibers, continuous fibers, or a mixture of long fibers and continuous fibers are used as reinforcing fibers in a plastic base material are joined to both side bracket parts for fastening to the vehicle body in the case main body. Patent Document 1 describes that the above-mentioned battery pack case assembly for an electric vehicle can reduce weight while simultaneously improving rigidity, crashworthiness, and dimensional stability by using a lightweight plastic composite material as the case material.

[0004] Patent Document 1: JP 2013-201112 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there are cases where it is required to further prevent damage to the batteries in the battery pack in the event of a collision of the electric vehicle. On the other hand, there are cases where a reduction in the weight of the battery pack is required.

[0006] An object of one aspect of the present disclosure is to provide a lightweight battery pack that can suppress damage to a battery in the event of a collision of an electric vehicle, and a battery pack case in which the battery pack can be formed. [Means for solving the problem]

[0007] Means for solving the above problems include the following aspects. <1> A battery pack case used to form a battery pack to be mounted on an electric vehicle, A tray that is attached to a body of the electric vehicle; a battery holding member attached to at least a portion of the tray and holding a battery; a cover for covering the tray and the battery holding member; Equipped with At least two of the tray, the battery holder, and the cover include fiber-reinforced plastic; Battery pack case. <2> Further, a cover reinforcing member which is a metal plate or a fiber reinforced tape and which reinforces at least a portion of the cover is provided. <1> A case for a battery pack according to claim 1. <3> the tray includes a tray rear portion disposed under a rear seat of the electric vehicle, and a tray extension portion extending from the tray rear portion in a vehicle body front direction and having a length in a vehicle body width direction shorter than that of the tray rear portion, The battery holding member includes a battery holding member R attached to at least a portion of the rear of the tray, the cover includes a cover rear portion that covers the tray rear portion and the battery holding member R, and a cover extension portion that covers at least the tray extension portion, The cover reinforcing member includes a cover rear reinforcing member that reinforces at least a connection portion of the cover rear with the cover extension portion. <2> A case for a battery pack according to claim 1. <4> The tray further includes a tray front portion connected to an end portion of the tray extension portion in a vehicle body front direction and disposed under a front seat of the electric vehicle, Further, a tray front reinforcing member is provided, which is a metal member or a fiber reinforced tape, for reinforcing the edge of the front portion of the tray. <3> A case for a battery pack according to claim 1. <5> The battery holding member includes a battery holding member M attached to at least a portion of the tray extension, the cover extension covers the tray extension and the battery holding member M; The cover reinforcing member includes a cover extension reinforcing member that reinforces at least a portion of the area of ​​the cover extension that covers the battery holding member M. <3> or <4> A case for a battery pack according to claim 1. <6> Further, a tray extension reinforcing member is provided which is a metal plate and reinforces a portion of the tray extension in the vehicle body length direction, the portion being an area from one end to the other end in the vehicle body width direction, At least a portion of the tray extension reinforcing member is embedded in the tray extension. <3> A case for a battery pack according to claim 1. <7> At least one of the tray and the cover comprises a fiber-reinforced plastic containing two or more types of fibers selected from the group consisting of glass fiber, aramid fiber, carbon fiber, Zylon fiber, polyethylene fiber, and boron fiber; <1> ~ <6> 13. A battery pack case according to claim 12, wherein <8> the battery holding member is a battery module holding member that holds a battery module formed by stacking a plurality of lithium secondary batteries in a thickness direction, The battery module holding member is a pair of end plates for sandwiching the battery module from outside both ends of the battery module in the thickness direction; a pair of side plates for sandwiching the battery module from outsides of both ends of the battery module in a direction perpendicular to the thickness direction and the vertical direction; Including, The pair of end plates and the pair of side plates include the fiber reinforced plastic. <1> ~ <7> 13. A battery pack case according to claim 12, wherein <9> The pair of end plates are plate-shaped members having a structure in which a metal member is embedded in a fiber-reinforced plastic. <8> A case for a battery pack according to claim 1. <10> The battery pack further includes an impact absorbing layer disposed at least in one location between the pair of end plates and the battery module and between the battery module and the tray. <8> or <9> A case for a battery pack according to claim 1. <11> A battery pack mounted on an electric vehicle, <1> ~ <10> A battery pack case according to any one of claims 1 to 4, a battery held by the battery holding member in the battery pack case; A battery pack comprising: Effect of the Invention

[0008] According to one aspect of the present disclosure, there is provided a lightweight battery pack that can suppress damage to a battery in the event of a collision of an electric vehicle, and a battery pack case in which the battery pack can be formed. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view of a vehicle body of an electric vehicle equipped with a battery pack according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a schematic perspective view of a battery pack according to an embodiment of the present disclosure. [Diagram 3] 1 is an exploded perspective view conceptually illustrating a state in which a cover is removed from a tray in a battery pack according to an embodiment of the present disclosure. FIG. [Figure 4] 1 is a schematic perspective view of a battery pack according to an embodiment of the present disclosure, with a cover indicated by dotted lines; [Diagram 5] FIG. 2 is a schematic bottom view of a battery pack according to an embodiment of the present disclosure. [Figure 6] FIG. 2 is a schematic perspective view of a rear portion of a tray and a battery holding member attached to the rear portion of the tray in a battery pack according to an embodiment of the present disclosure. [Figure 7] 7 is a schematic perspective view showing a state in which the battery holding member shown in FIG. 6 holds a battery module. [Figure 8] 1 is a schematic perspective view showing an end plate that constitutes a part of a battery holding portion in a battery pack according to an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, the amount of each component in a composition means, when a plurality of substances corresponding to each component are present in the composition, the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0011] [Battery pack case] The battery pack case of the present disclosure is a battery pack case used to form a battery pack to be mounted on an electric vehicle, A tray that is attached to a body of the electric vehicle; a battery holding member attached to at least a portion of the tray and holding the battery; a cover for covering the tray and the battery holding member; Equipped with At least two of the tray, the battery retainer, and the cover comprise fiber-reinforced plastic; This is a case for a battery pack.

[0012] As a result of extensive research, the inventors have discovered that by incorporating fiber-reinforced plastic into at least two of the tray, battery holding member, and cover in a battery pack case that includes a tray, battery holding member, and cover, it is possible to effectively reduce the weight of the battery pack and prevent damage to the battery in the event of a collision of the electric vehicle, and based on this discovery, have discovered the battery pack case of the present disclosure. In other words, the battery pack case of the present disclosure makes it possible to form a lightweight battery pack that can further reduce damage to the battery in the event of a collision of the electric vehicle.

[0013] A battery pack formed using the battery pack case of the present disclosure exhibits an excellent effect in suppressing damage to the battery even in the event of a side collision of an electric vehicle. In particular, the side impact test in the examples described later is a new standard evaluation test established by the Ministry of Land, Infrastructure, Transport and Tourism of Japan in June 2018 ("Standards for Occupant Protection in Side Impact with Utility Pole, etc."). The battery pack formed using the battery pack case of the present disclosure exhibits excellent effects in suppressing damage to the battery even in the side impact test, which is the new standard evaluation test (see examples described later).

[0014] The battery pack case of the present disclosure preferably further includes a cover reinforcing member that reinforces at least a portion of the cover, thereby making it possible to more effectively prevent damage to the battery in the event of a collision of the electric vehicle. More preferably, the cover reinforcing member is a metal plate or a fiber-reinforced tape.

[0015] The tray in the battery pack case is A rear portion of the tray that is placed under the rear seat of the electric vehicle; a tray extension portion that extends from the rear portion of the tray toward the front of the vehicle body and has a length in the vehicle body width direction shorter than that of the rear portion of the tray; may include. In this embodiment (hereinafter referred to as "embodiment A"), a large rear portion of the tray can be placed in the large area under the rear seat in the floor panel of the electric vehicle, and a large battery holding member can be placed on the rear portion of the tray. Therefore, embodiment A increases the amount (volume) of batteries that can be stored in the battery pack. The battery holding member attached to the rear of the tray is sometimes referred to as a battery holding member R.

[0016] Here, the tray rear portion and the tray extension portion do not need to be formed as separate members, but may be formed as a single, integrally molded member. The tray including the tray rear portion, the tray extension portion, and the tray front portion, which will be described later, may also be a single integrally molded member. The same applies to a cover including a cover rear portion and a cover extension portion, and a cover including a cover rear portion, a cover extension portion, and a cover front portion, which will be described later.

[0017] In the above-mentioned embodiment A, the battery holding member may be attached not only to the rear part of the tray but also to the tray extension part. Hereinafter, the battery holding member attached to the tray extension part may be referred to as the battery holding member M.

[0018] In the above-mentioned embodiment A, the tray may further include a tray front portion connected to an end of the tray extension portion in the vehicle front direction. The tray front portion is preferably disposed under the front seat of the electric vehicle. When the tray includes a tray front, the battery holder may be attached not only to the tray rear but also to the tray front. The battery holder attached to the tray front may be hereinafter referred to as the battery holder F.

[0019] In a battery pack case having a cover reinforcing member, the tray includes a tray rear portion disposed under a rear seat of the electric vehicle, and a tray extension portion extending from the tray rear portion toward a front side of the vehicle body and having a length in a vehicle body width direction shorter than that of the tray rear portion; The battery retaining member includes a battery retaining member R attached to at least a portion of the rear of the tray; the cover includes a cover rear portion that covers the tray rear portion and the battery holding member R, and a cover extension portion that covers at least the tray extension portion; It is preferable that the cover reinforcing member includes a cover rear reinforcing member that reinforces at least the connection portion of the cover rear with the cover extension portion.

[0020] In a case where the tray includes the tray rear portion and the tray extension portion, the battery holding member includes the battery holding member R, and the cover includes the cover rear portion and the cover extension portion, if the cover reinforcing member includes a cover rear reinforcing member, damage to the battery in the event of a collision of the electric vehicle (especially a side collision) is more effectively suppressed.

[0021] In a battery pack case in which the tray includes a tray rear portion and a tray extension portion (preferably, a battery pack case in which a cover rear reinforcing member is provided), The tray may further include a tray front portion connected to an end of the tray extension portion in a vehicle body forward direction and disposed under a front seat of the electric vehicle. In this case, the battery pack case preferably further includes a tray front reinforcing member that is a metal member or a fiber-reinforced tape that reinforces the edge of the front of the tray, thereby more effectively preventing damage to the battery in the event of a collision of the electric vehicle.

[0022] In a battery pack case having a cover rear reinforcing member, The battery holding member includes a battery holding member M attached to at least a portion of the tray extension, The cover extension covers the tray extension and the battery holding member M, The cover reinforcing member preferably includes a cover extension reinforcing member that reinforces at least a portion of the area of ​​the cover extension that covers the battery holding member M. When the cover reinforcing member includes a cover extension reinforcing member, damage to the battery in the event of a collision of the electric vehicle is more effectively suppressed.

[0023] The battery pack case preferably further includes a tray extension reinforcing member that is a metal plate and reinforces a portion of the tray extension in the vehicle body length direction, from one end to the other end in the vehicle body width direction. When the battery pack case includes the tray extension reinforcing member, damage to the battery in the event of a collision of the electric vehicle (particularly a side collision) is more effectively suppressed. It is preferable that at least a portion of the tray extension reinforcing member is embedded in the tray extension.

[0024] The battery holding member in the battery pack case is preferably a battery module holding member that holds a battery module formed by stacking a plurality of lithium secondary batteries in the thickness direction. The battery module holding member preferably comprises: a pair of end plates for holding the battery module from outside both ends in the thickness direction of the battery module (i.e., the thickness direction of the plurality of lithium secondary batteries (i.e., the stacking direction)); a pair of side plates for sandwiching the battery module from outsides of both ends of the battery module in a direction perpendicular to the thickness direction and the vertical direction; Includes. The pair of end plates and the pair of side plates preferably include fiber reinforced plastic. This more effectively reduces the weight of the battery pack and reduces damage to the battery in the event of a collision.

[0025] The pair of end plates are preferably plate-like members having a structure in which a metal member is embedded in fiber-reinforced plastic. This more effectively reduces the effect of preventing damage to the battery in the event of a collision and reduces its weight.

[0026] The battery pack case preferably further includes a shock absorbing layer disposed in at least one location between the pair of end plates and the battery module and between the battery module and the tray. This more effectively suppresses damage to the battery in the event of a collision.

[0027] In the battery pack case, the tray and the cover are preferably joined directly or via a joining member, which can prevent water, dust, etc. from entering the battery pack and can prevent deterioration of the battery. In order to more effectively obtain the above-mentioned effects, it is more preferable that the tray and the cover are joined via a sealing member (eg, a gasket) serving as a joining member.

[0028] The sealing member is preferably integrated with the tray or cover, which can reduce the number of parts and simplify the structure of the battery pack case.

[0029] [Battery pack] The battery pack of the present disclosure is a battery pack to be mounted on an electric vehicle, A battery pack case according to the present disclosure; a battery held by the battery holding member in a battery pack case; Equipped with. The battery pack of the present disclosure provides the same effects as those provided by the battery pack case of the present disclosure.

[0030] The battery pack of the present disclosure preferably comprises a battery module containing a plurality of batteries. In this case, the battery holding member is preferably a battery module holding member that holds the battery module. The preferred form of the battery module is as explained in the section "Battery Pack Case."

[0031] Moreover, the battery module including a plurality of batteries is preferably a battery module in which a plurality of lithium secondary batteries are stacked in the thickness direction. Each of the multiple lithium secondary batteries may be a stacked type lithium secondary battery in which electrodes (positive and negative electrodes) are stacked, or a wound type lithium secondary battery in which electrodes (positive and negative electrodes) are wound. For the battery module, reference can be made to publicly known documents such as Japanese Patent No. 6751570 and Japanese Patent No. 6645500 as appropriate.

[0032] The battery pack of the present disclosure can be formed by holding a battery (preferably a battery module) in the battery pack case of the present disclosure. When the charge / discharge cycle of the battery in the formed battery pack is repeated and the battery deteriorates, the battery in the battery pack may be replaced, i.e., the deteriorated battery may be removed from the battery pack case in the battery pack and a new battery may be inserted.

[0033] [Embodiment] Hereinafter, an embodiment of a battery pack according to the present disclosure will be described with reference to the drawings, and an embodiment of a battery pack case according to the present disclosure will also be described in the description. The embodiment of the battery pack case according to the present disclosure is a battery pack according to the following embodiment, except that the battery is removed. The battery pack and the battery pack case of the present disclosure are not limited to the following embodiments. Elements common to the various drawings are given the same reference numerals and duplicated descriptions may be omitted.

[0034] FIG. 1 is a schematic perspective view of the body of an electric vehicle equipped with a battery pack according to this embodiment, and FIG. 2 is a schematic perspective view of the battery pack according to this embodiment. 1 and 2, a battery pack 10 according to this embodiment is mounted in a vehicle body 100 of an electric vehicle. The battery pack 10 includes a battery pack case including a tray 14 and a cover 12, and a battery module accommodated in the battery pack case. FIG. 3 is an exploded perspective view conceptually showing the battery pack with cover 12 removed from tray 14. As shown in FIG.

[0035] As shown in FIG. 2 and FIG. 3, the battery pack case forming the battery pack 10 is A tray 14 attached to a body 100 of the electric vehicle; a battery holding member (18F, 18M, 18R) attached to at least a portion of the tray 14 and holding the batteries; A cover 12 that covers the tray 14 and the battery holding member; Equipped with.

[0036] The battery pack 10 is configured by holding batteries (more specifically, a battery module 16F, a battery module 16M, and a battery module 16R, which will be described later) in the battery holding member in the battery pack case.

[0037] In the battery pack 10, a sealing member (e.g., a gasket) (not shown) is interposed at the joint between the tray 14 and the cover 12. This seals the battery pack and prevents water, dust, and the like from entering the battery pack. The sealing member is integrated with the tray or the cover.

[0038] The tray 14 includes a tray rear portion 14R, a tray extension portion 14M, and a tray front portion 14F. The tray rear portion 14R is disposed under the rear seat of the electric vehicle. The tray extension 14M is a portion that extends from the tray rear portion 14R toward the front of the vehicle body (the direction of the arrow FR in FIG. 1; the same applies below). The tray extension 14M is a member that is shorter in length in the vehicle body width direction (the direction of the arrow W in FIG. 1) than the tray rear portion 14R. The tray front portion 14F is connected to an end portion of the tray extension portion 14M in the vehicle body front direction. The tray front portion 14F is disposed under the front seat of the electric vehicle.

[0039] A battery holder 18R for holding a battery module 16R is attached to the rear portion 14R of the tray. A battery holding member 18M for holding a battery module 16M is attached on the tray extension portion 14M. A battery holding member 18F for holding a battery module 16F is attached on the tray front portion 14F. The battery holding member 18R, the battery holding member 18M, and the battery holding member 18F are members for holding the battery module 16R, the battery module 16M, and the battery module 16F, respectively. Each of the battery module 16R, the battery module 16M, and the battery module 16F is a battery module formed by stacking a plurality of lithium secondary batteries in the thickness direction. The detailed structures of battery holding members 18R, 18M, and 18F will be described later.

[0040] The cover 12 includes a cover rear portion 12R, a cover extension portion 12M, and a cover front portion 12F. The cover rear portion 12R is the portion of the cover 12 that covers the tray rear portion 14R, the battery holding member 18R, and the battery module 16R. The cover extension 12M is the portion of the cover 12 that covers the tray extension 14M, the battery holding member 18M, and the battery module 16M. The cover front portion 12F is the portion of the cover 12 that covers the tray front portion 14F, the battery holding member 18F, and the battery module 16F.

[0041] In battery pack 10, at least two of the tray, battery holding member, and cover (i.e., the combination of the tray and battery holding member, the combination of the battery holding member and cover, the combination of the tray and cover, or the combination of the tray, battery holding member, and cover) contain fiber-reinforced plastic. This effectively reduces the weight of the battery pack and reduces damage to the battery in the event of a collision of the electric vehicle.

[0042] FIG. 4 is a schematic perspective view of the battery pack according to this embodiment in which the cover 12 is indicated by a dotted line, and corresponds to FIG. In FIG. 4, the cover 12 is shown by dotted lines to make the cover reinforcing members (that is, cover rear reinforcing member 20RF, cover rear reinforcing member 20RS, cover rear reinforcing member 20RR, cover extension reinforcing member 20M, and cover front reinforcing member 20F) easier to see.

[0043] As shown in Fig. 4, when the cover is attached to the tray, each of the cover reinforcing members for reinforcing the cover covers at least a portion of the battery module on the tray. These cover reinforcing members protect at least a portion of the battery module on the tray, effectively preventing damage to the batteries in the event of a collision.

[0044] Each of the cover reinforcing members is actually attached to the inner wall of the cover 12 or embedded in the cover 12, thereby reinforcing a part of the cover (specifically, the part covering the battery). Each of the cover reinforcing members is preferably a metal plate or a fiber reinforced tape. The cover reinforcement member, which may be a fiber reinforced tape, is preferably applied to the inner wall of the cover 12 . The cover reinforcing member in the form of a metal plate may be attached to the inner wall of the cover 12 or may be embedded in the cover 12 .

[0045] The cover reinforcing members include a cover rear reinforcing member 20RF, a cover rear reinforcing member 20RS, a cover rear reinforcing member 20RR, a cover extension reinforcing member 20M, and a cover front reinforcing member 20F. The cover rear reinforcing member 20RF is a member that reinforces at least the connection portion of the cover rear portion 12R with the cover extension portion 12M (in other words, the vehicle body front portion of the cover rear portion 12R). The cover rear reinforcing member 20RS is a member that reinforces both ends of the cover rear portion 12R in the vehicle body width direction, The cover rear reinforcing member 20RR is a member that reinforces the rear portion of the cover rear portion 12R toward the rear of the vehicle body. The cover extension reinforcing member 20M is a member that reinforces the cover extension 12M, The cover front reinforcing member 20F is a member that reinforces the cover front portion 12F.

[0046] As mentioned above, each cover reinforcing member contributes to reducing damage to the battery during a collision, but in particular, the cover rear reinforcing member 20RF, which reinforces at least the connection portion of the cover rear portion 12R with the cover extension portion 12M, is particularly effective in reducing damage to the battery during a collision (especially a side collision).

[0047] The battery pack 10 further includes a tray front reinforcing member 22F that reinforces the edge of the tray front 14F, thereby further reducing damage to the battery placed on the tray front in the event of a collision.

[0048] The tray front reinforcement member 22F is preferably a metal member or a fiber reinforced tape. At least a portion of the tray front reinforcement member 22F, which may be a metal member, may be embedded in the tray front 14F.

[0049] FIG. 5 is a schematic bottom view of the battery pack 10 (ie, a schematic bottom view of the tray). The battery pack 10 includes a tray extension reinforcing member 30M embedded in the lower surface side of the tray extension 14M. The tray extension reinforcing member 30M reinforces a portion of the tray extension 14M in the vehicle body length direction, from one end to the other end in the vehicle body width direction, thereby achieving a significant effect in suppressing damage to the battery in a collision (particularly a side collision). The tray extension reinforcing member 30M is preferably a metal plate.

[0050] Next, the structures of the battery holding member 18R and the battery module 16R will be described. The structure of each of the battery holding members 18M and 18F is similar to the structure of the battery holding member 18R, and the structure of each of the battery modules 16M and 16F is similar to the structure of the battery module 16R.

[0051] As shown in FIGS. 3 and 4, the battery holding member 18R is a battery module holding member that holds a battery module 16R formed by stacking a plurality of lithium secondary batteries in the thickness direction. Fig. 6 is a schematic perspective view of the rear part of the tray and the battery holder attached to the rear part of the tray, in which the battery module 16R has been removed from the rear part 14 of the tray in Figs. 3 and 4 in order to make it easier to see the configuration of the battery holder. Fig. 7 is a schematic perspective view showing a state in which the battery holding member shown in Fig. 6 holds a battery module. Fig. 7 corresponds to an enlarged view of the rear side of the tray of the battery pack 10 in Fig. 3.

[0052] As shown in FIGS. 6 and 7, a battery holding member 18R which is a battery module holding member includes a pair of end plates 18E and a pair of side plates 18S. The pair of end plates 18E sandwich the battery module 16R from the outside of both ends in the thickness direction of the multiple lithium secondary batteries in the battery module 16R (i.e., the stacking direction in which the multiple lithium secondary batteries are stacked). Here, the end plate 18E and the lithium secondary battery in the outermost layer may be adjacent to each other, or another layer (for example, an impact absorbing layer) may be interposed between the end plate 18E and the lithium secondary battery in the outermost layer. The function of the pair of end plates 18E is to sandwich the battery module 16R from the outside of both ends. Another function of the pair of end plates 18E is to suppress swelling of the battery module R due to repeated charge / discharge cycles. The swelling of the battery module R is caused by swelling of the multiple lithium secondary batteries in the thickness direction. The pair of end plates 18E may further have other functions, such as a shock absorbing function.

[0053] The pair of side plates 18S sandwich the battery module 16R from outside both ends of the battery module in the thickness direction of the multiple lithium secondary batteries and in a direction perpendicular to the vertical direction (in this example, the vehicle body width direction). The function of the pair of side plates 18S is to sandwich the battery module 16R from the outside of both ends. Another function of the pair of side plates 18S is to prevent lateral displacement of the multiple lithium secondary batteries in the battery module. The pair of side plates 18S may have other functions such as a heat dissipation function and a cooling function. One method for providing the side plate 18S with a heat dissipation function is to provide through holes that penetrate the side plate in the thickness direction. One method for providing the side plate 18S with a cooling function is to embed a cooling member (for example, a pipe for circulating a cooling medium) in the side plate.

[0054] 6 and 7, in the battery holding member 18R, a pair of end plates 18E and a pair of side plates 18S form a frame, and a battery module is housed in this frame. In the battery holding member 18R, five of the frames are lined up in the vehicle body width direction, and adjacent frames share one side plate 18S. That is, the battery holding member 18R has six side plates 18S and ten end plates 18E. The number of side plates 18S and end plates 18E (in other words, the number of the above-mentioned "frames") can be changed as appropriate.

[0055] 6, an impact absorbing layer 28 is disposed in the area on the tray rear portion 14R where the battery module is held (under the battery module when the battery module is held), which more effectively suppresses damage to the battery in the event of a collision.

[0056] FIG. 8 is a schematic perspective view showing an end plate that constitutes a part of the battery holding portion. The end plate 18E is preferably a plate-like member having a structure in which a cylindrical metal member 32 is embedded in fiber-reinforced plastic. This more effectively suppresses damage to the battery in the event of a collision (the effect of the metal member) and reduces the battery's weight (the effect of the fiber-reinforced plastic base). In this case, a metal bolt (not shown) may pass through the inside of the cylindrical metal member 32. The metal member may also be cylindrical.

[0057] [Embodiment] Although the embodiments of the battery pack and the battery pack case of the present disclosure have been described above, the battery pack and the battery pack case of the present disclosure are not limited to the above-described embodiments. As long as the requirements of the battery pack and battery pack case of the present disclosure are met, modifications to the above-described embodiments that are modified in various ways are also within the scope of the battery pack and battery pack case of the present disclosure.

[0058] For example, the following examples are examples of modifications of the battery pack of the above embodiment. As a modified example, compared to the battery pack of the above embodiment, there is an example in which the tray front portion, the battery holding portion and the battery on the tray front portion, and the cover front portion are omitted to make the battery pack smaller. As a modification, there may be mentioned an example in which the battery holding member and the battery on the tray extension portion and / or the battery holding member and the battery on the tray front portion are omitted from the battery pack of the above embodiment. As a modified example, instead of a tray including a tray rear portion and a tray extension portion that have different lengths in the vehicle width direction, for example, a rectangular tray may be combined with a cover that fits the shape of the tray.

[0059] In short, the battery pack case of the present disclosure only needs to include a tray, a battery holding member, and a cover, and there are no particular limitations on the shapes of the tray, cover, and other members.

[0060] [Preferable materials for each component of the battery pack case] Next, preferred materials for each member of the battery pack case of the present disclosure will be described.

[0061] <Fiber reinforced plastics> In the battery pack case of the present disclosure, at least two of the tray, the battery holding member, and the cover include fiber reinforced plastic. This provides the effect of suppressing damage to the battery in the event of a collision and the effect of reducing the weight of the battery pack case.

[0062] The fibers contained in the fiber-reinforced plastic are not particularly limited as long as they are fibers contained in ordinary fiber-reinforced plastics. From the viewpoint of further suppressing damage to the battery, the fiber reinforced plastic preferably contains at least one type of fiber selected from the group consisting of glass fiber, aramid fiber, carbon fiber, Zylon fiber, polyethylene fiber, and boron fiber.

[0063] In the present disclosure, in order to further suppress damage to the battery, In the battery pack case of the present disclosure, at least one of the tray and the cover is It is preferred that the material comprises a fiber-reinforced plastic, More preferably, it comprises a fiber-reinforced plastic containing two or more types of fibers, It is more preferable that the material contains a fiber-reinforced plastic containing two or more kinds of fibers selected from the group consisting of glass fiber, aramid fiber, carbon fiber, Zylon fiber, polyethylene fiber, and boron fiber.

[0064] The ratio of the fiber content to the total amount of the fiber reinforced plastic is preferably 20% by mass to 70% by mass, and more preferably 30% by mass to 60% by mass, based on the total amount of the fiber reinforced plastic. The preferred range of the ratio of the fiber content to the total amount of the component containing fiber-reinforced plastic is similar to the preferred range of the ratio of the fiber content to the total amount of the fiber-reinforced plastic.

[0065] There are no particular limitations on the resin (i.e., matrix resin) in the fiber reinforced plastic, and any known resin can be used. Examples of resins include polypropylene, polyester (i.e., saturated polyester or unsaturated polyester), polyamide, polyether ether ketone, polycarbonate, polyphenylene sulfone, polyphenylene ether, thermoplastic polyurethane, and the like. The fiber reinforced plastic may contain only one type of resin or may contain two or more types of resin.

[0066] The ratio of the resin content to the total amount of the fiber reinforced plastic is preferably 30% by mass to 80% by mass, and more preferably 40% by mass to 70% by mass, based on the total amount of the fiber reinforced plastic. The preferred range of the ratio of the resin content to the total amount of the member containing fiber-reinforced plastic is similar to the preferred range of the ratio of the resin content to the total amount of the fiber-reinforced plastic.

[0067] The fiber reinforced plastic may contain components (additives, etc.) other than the fibers and resin. The additives include a flame retardant (preferably a bromine-based flame retardant).

[0068] The content ratio of the flame retardant to the total amount of the fiber reinforced plastic is preferably 10% by mass to 30% by mass, and more preferably 20% by mass to 30% by mass, based on the total amount of the fiber reinforced plastic. The preferred range of the ratio of the content of the flame retardant to the total amount of the member containing fiber reinforced plastic is similar to the preferred range of the ratio of the content of the flame retardant to the total amount of the fiber reinforced plastic.

[0069] Members containing fiber-reinforced plastics (for example, trays, battery holding members, or covers) can be manufactured by known molding methods such as injection molding, SMC (Sheet Molding Compound) molding, press molding, and extrusion press molding.

[0070] <Reinforcing material> As described above, the battery pack case of the present disclosure may include a reinforcing member (for example, a cover reinforcing member, a tray reinforcing member, etc.).

[0071] The shape of the reinforcing member can be appropriately selected taking into consideration the shape of the member to be reinforced by the reinforcing member, the strength of reinforcement, etc. Examples of the shape of the reinforcing member include a plate shape, a rod shape, a tube shape, a sheet shape (for example, the shape of a fiber-reinforced tape), etc.

[0072] The reinforcing member is preferably a metal member (for example, a metal plate, a metal rod, etc.) or a fiber-reinforced tape. The material of the metal member is not particularly limited, and known materials such as aluminum, aluminum alloys, and stainless steel can be used. The material of the fiber-reinforced tape is not particularly limited, and any known material can be used. Examples of the material of the fiber-reinforced tape include the same materials as those of the fiber-reinforced plastics described above.

[0073] <Sealing member> As described above, the battery pack case of the present disclosure preferably includes a sealing member (eg, a gasket) interposed between the tray and the cover.

[0074] The sealing member preferably contains at least one thermoplastic elastomer. Examples of the thermoplastic elastomer include: Olefin elastomers (e.g., TPO, TPV, etc.), Styrene-based elastomers (e.g., SEEPS, SEPS, SEBS, etc.), Urethane elastomer, Polyvinyl chloride elastomers (e.g., TPVC), Polyamide elastomers (e.g., PAER, TPAE, etc.), Polyester elastomers (e.g., TPEE), Acrylic rubber, Ethylene propylene rubber, etc.

[0075] <Shock absorbing layer> As mentioned above, it is preferable that the battery pack case further includes an impact absorbing layer (e.g., impact absorbing layer 28) disposed in at least one location between the pair of end plates and the battery module, and between the battery module and the tray. The impact absorbing layer preferably contains at least one thermoplastic elastomer. The material of the impact absorbing layer may be the same as the material of the sealing member described above. EXAMPLES

[0076] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples. Hereinafter, wt% and weight essentially mean mass% and mass.

[0077] [Examples 1 to 40, Comparative Examples 1 to 5] For the battery pack 10 (see Figures 1 to 5) according to the above-described embodiment, simulations were performed regarding the G-shock test Z-axis, weight reduction rate, and side impact test when the materials shown in Tables 1 and 2 were selected as the materials for the cover, tray, and battery holding member. Details of the materials shown in Tables 1 and 2 are as follows.

[0078] ·Al alloy: Aluminum alloy (aluminum-silicon type, A4032) · SMC: SMC molding resin manufactured by Japan Composites (contains unsaturated polyester resin as matrix resin) ·PP... Polypropylene GF: Glass fiber (manufactured by Nittobo, fiber diameter φ17μm, fiber length 1mm) ·LGF: Long glass fiber (manufactured by Nittobo, fiber diameter φ17μm, fiber length 8mm) CF: Carbon fiber (Teijin, fiber diameter φ7μm, fiber length 1mm) ·LCF...Carbon long fiber (Teijin, fiber diameter φ7μm, fiber length 9mm) · Arlen M335 ... Mitsui Chemicals' "Arlen" (registered trademark) M335 (modified polyamide 6T)

[0079] In Tables 1 and 2, the columns for the material of each of the cover, tray, and battery holding member indicate the type of resin, and the type and content of fiber (the content of that fiber relative to the total content of resin and fiber). For example, the expression "SMC GF37wt% + CF2wt%" means that, when the total amount of resin and fiber is 100% by mass, the material contains 37% by mass of glass fiber (GF), 2% by mass of carbon fiber (CF), and the remainder is resin (SMC). In addition, the cover reinforcing member used in all the examples was made of the above-mentioned Al alloy.

[0080] The simulation was performed using the nonlinear structural analysis software LS-DYNA (JSOL Corporation) under MAT-24 conditions.

[0081] -Simulation conditions- Vehicle weight: 1680kg Total battery weight: 210kg Weight of battery pack case: 1,470 kg (Comparative Example 1)

[0082] The evaluation contents and evaluation criteria for the G-shock test Z axis, weight reduction rate, and side impact test are as follows:

[0083] - Evaluation of the Z-axis of the G-Shock test - In the G-shock Z-axis test, an electric vehicle equipped with a battery pack was subjected to an impact with an acceleration of 18G in the X-axis direction, 15G in the Y-axis direction, and 25G in the Z-axis direction. The impact on the breakage of the battery pack case and the battery inside the battery pack was confirmed and evaluated according to the following evaluation criteria. In the following evaluation criteria, the most excellent effect of preventing damage to the battery in the event of an electric vehicle collision is ranked "A."

[0084] -G-Shock test Z-axis evaluation criteria- A: There is no breakage in the battery pack case. B: Part of the battery pack case breaks, but the battery inside the battery pack is not affected. C: At least a part of the battery pack case breaks, affecting the battery inside the battery pack.

[0085] -Evaluation of weight reduction rate- The reduction rate (%) of the total mass of the cover, tray, and battery holding member of each Example relative to the total mass of the cover (made of Al alloy), tray (made of Al alloy), and battery holding member (made of Al alloy) in Comparative Example 1 was determined, and the weight reduction rate of the battery pack case was evaluated according to the following evaluation criteria. In the following evaluation criteria, the most excellent weight reduction rate (i.e., the most lightweight) is ranked as "A".

[0086] -Evaluation criteria for weight reduction rate- A: The reduction rate (%) of the total mass of the cover, tray, and battery holding member was 10% or more. B: The reduction rate (%) of the total mass of the cover, the tray, and the battery holding member was 5% or more and less than 10%. C: The reduction rate (%) of the total mass of the cover, the tray, and the battery holding member was less than 5%.

[0087] -Side impact test evaluation details- An electric vehicle equipped with a battery pack was collided sideways with a pole measuring 254 mm in diameter at a speed of 32 km / h and an impact angle of 75°. The fracture of the battery pack case and the effect on the battery inside the battery pack were checked and evaluated according to the following criteria.

[0088] - Evaluation criteria for side impact tests - A: There is no breakage in the battery pack case. B: Part of the battery pack case breaks, but the battery inside the battery pack is not affected. C: At least a part of the battery pack case breaks, affecting the battery inside the battery pack.

[0089] [Table 1]

[0090] [Table 2]

[0091] As shown in Tables 1 and 2, in Examples 1 to 40, which satisfied the condition that at least two of the tray, battery holding member, and cover contained fiber-reinforced plastic, the weight reduction rate of the battery pack case was superior (i.e., the battery pack case was lighter) compared to Comparative Examples 1 to 5, which did not satisfy this condition. Furthermore, relatively good results were obtained in the G-shock Z-axis test and the side impact test in Examples 1 to 40. This confirmed that damage to the battery in the event of a collision could be suppressed.

[0092] From the results of Examples 1 to 40, it was confirmed that when at least one of the tray and the cover contained fiber-reinforced plastic containing two or more types of fibers (Examples 3 to 21 and 25 to 40), the results of the G-shock test Z-axis and the side impact test were superior, that is, damage to the battery in the event of a collision (including a side impact) could be more effectively suppressed.

[0093] The disclosure of Japanese Patent Application No. 2021-006442, filed on January 19, 2021, is incorporated by reference in its entirety into this specification. All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A battery pack case used to form a battery pack to be mounted on an electric vehicle, A tray that is attached to a body of the electric vehicle; a battery holding member attached to at least a portion of the tray and holding a battery; a cover for covering the tray and the battery holding member; Equipped with At least two of the tray, the battery holding member, and the cover include fiber-reinforced plastic; Further, a cover reinforcing member which is a metal plate or a fiber reinforced tape and which reinforces at least a part of the cover is provided, the tray includes a tray rear portion disposed under a rear seat of the electric vehicle, and a tray extension portion extending from the tray rear portion in a vehicle body front direction and having a length in a vehicle body width direction shorter than that of the tray rear portion, The battery holding member includes a battery holding member R attached to at least a portion of the rear part of the tray, the cover includes a cover rear portion that covers the tray rear portion and the battery holding member R, and a cover extension portion that covers at least the tray extension portion, The cover reinforcing member includes a cover rear reinforcing member that reinforces at least a connection portion of the cover rear with the cover extension portion. Battery pack case.

2. The tray further includes a tray front portion connected to an end portion of the tray extension portion in a vehicle body front direction and disposed under a front seat of the electric vehicle, Further, a tray front reinforcing member is provided, which is a metal member or a fiber reinforced tape, for reinforcing the edge of the front portion of the tray. The battery pack case according to claim 1 .

3. The battery holding member includes a battery holding member M attached to at least a portion of the tray extension portion, the cover extension covers the tray extension and the battery holding member M; The cover reinforcing member includes a cover extension reinforcing member that reinforces at least a portion of the area of ​​the cover extension that covers the battery holding member M. The battery pack case according to claim 1 or 2.

4. Further, a tray extension reinforcing member is provided which is a metal plate and reinforces a portion of the tray extension in the vehicle body length direction, the portion being an area from one end to the other end in the vehicle body width direction, At least a portion of the tray extension reinforcing member is embedded in the tray extension. The battery pack case according to any one of claims 1 to 3.

5. The battery pack case according to any one of claims 1 to 4, wherein at least one of the tray and the cover comprises a fiber-reinforced plastic containing two or more types of fibers selected from the group consisting of glass fiber, aramid fiber, carbon fiber, Zylon fiber, polyethylene fiber, and boron fiber.

6. the battery holding member is a battery module holding member that holds a battery module formed by stacking a plurality of lithium secondary batteries in a thickness direction, The battery module holding member is a pair of end plates for sandwiching the battery module from outside both ends of the battery module in the thickness direction; a pair of side plates for sandwiching the battery module from outsides of both ends of the battery module in a direction perpendicular to the thickness direction and the vertical direction; Including, The pair of end plates and the pair of side plates include the fiber reinforced plastic. The battery pack case according to any one of claims 1 to 5.

7. A battery pack case used to form a battery pack to be mounted on an electric vehicle, comprising: A tray that is attached to a body of the electric vehicle; a battery holding member attached to at least a portion of the tray and holding a battery; a cover for covering the tray and the battery holding member; Equipped with At least two of the tray, the battery holding member, and the cover include fiber-reinforced plastic; the battery holding member is a battery module holding member that holds a battery module formed by stacking a plurality of lithium secondary batteries in a thickness direction, The battery module holding member is a pair of end plates for sandwiching the battery module from outside both ends of the battery module in the thickness direction; a pair of side plates for sandwiching the battery module from outsides of both ends of the battery module in a direction perpendicular to the thickness direction and the vertical direction; Including, The pair of end plates and the pair of side plates include the fiber reinforced plastic. Battery pack case.

8. 8. The battery pack case according to claim 6, wherein the pair of end plates are plate-like members having a structure in which a metal member is embedded in fiber-reinforced plastic.

9. The battery pack case according to any one of claims 6 to 8, further comprising an impact absorbing layer disposed in at least one location between the pair of end plates and the battery module and between the battery module and the tray.

10. A battery pack mounted on an electric vehicle, A battery pack case according to any one of claims 1 to 9, a battery held by the battery holding member in the battery pack case; A battery pack comprising:

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