JP7687014B2 - Battery pack - Google Patents

Description

This disclosure relates to a battery pack installed in a vehicle.

Patent Document 1 discloses an electrolyte regeneration device for a flow battery. This electrolyte regeneration device is configured to store oxidized or reduced electrolyte in a positive electrode electrolyte storage section and a negative electrode electrolyte storage section. A battery module that includes the flow battery as a unit cell is used as a power source for vehicles, etc.

Special table 2019-533890 publication

For example, it is conceivable to house a positive electrode side device and a negative electrode side device, such as the positive electrode electrolyte storage unit and the negative electrode electrolyte storage unit described in Patent Document 1, together with one or more battery cells in a battery pack case. When such a positive electrode side device and a negative electrode side device are separately constructed and arranged side by side in the case, the battery pack is required to have a structure that can suppress an electrical short circuit between the positive electrode side device and the negative electrode side device when an impact load is applied to the battery pack.

This disclosure has been made in consideration of the above-mentioned problems, and aims to provide a battery pack having a simple structure that can suppress an electrical short circuit between a positive electrode side device and a negative electrode side device when an impact load acts on the battery pack.

A battery pack according to the present disclosure is mounted on a vehicle. The battery pack includes one or more battery cells, a positive electrode side device, a negative electrode side device, and a case.
The positive and negative devices are arranged in a first direction and are separately configured. The case accommodates one or more battery cells, and the positive and negative devices. The positive and negative devices are disposed near one end of the case relative to the one or more battery cells in a second direction perpendicular to the first direction, as viewed from above the vehicle.
The case includes a first skeletal structural member extending along the second direction between the positive electrode side device and the negative electrode side device and formed to connect between the end wall of the case on the one end side and a skeleton portion of the case.

The skeleton may be a second skeleton structural member that is disposed between the positive and negative devices and one or more battery cells, and extends along the first direction to form the skeleton of the case.

The skeleton may be an end wall of the case located opposite the one end in the second direction.

The skeleton portion may be a second skeleton structural member disposed between the positive and negative devices and one or more battery cells, and extending along the first direction to form the skeleton of the case. The first skeleton structural member may be extended in the second direction to connect between the second skeleton structural member and an end wall of the case located on the opposite side of the one end in the second direction.

The battery pack may further include a positive electrode side vehicle attachment portion having a first fixing point with the vehicle at a position on the side of the positive electrode side device in the first direction away from the end wall of the case on the one end side in the second direction. The case may include a positive electrode side skeletal structural member that extends along the second direction with a straight line that passes through the first fixing point and is parallel to the second direction as a central axis when the vehicle is viewed from above, and that is formed to connect between the end wall of the case on the one end side and the second skeletal structural member.

The battery pack may further include a negative electrode side vehicle attachment portion having a second fixing point with the vehicle at a position on the side of the negative electrode side device in the first direction away from the end wall of the case on the one end side in the second direction. The case may include a negative electrode side skeletal structural member that extends along the second direction with a central axis that passes through the second fixing point and is parallel to the second direction when viewed from above the vehicle, and that is formed to connect between the end wall of the case on the one end side and the second skeletal structural member.

The first direction may be the width direction of the vehicle. And the second direction may be the front-rear direction of the vehicle.

According to the battery pack of the present disclosure, by including the above-mentioned first skeletal structural member, when an impact load is input to the case from the second direction on the positive side device side or the negative side device side, it is possible to make it difficult for damage to occur to both the positive side device and the negative side device. In this way, according to the present battery pack, it is possible to suppress electrical short circuits between the positive side device and the negative side device with a simple structure.

1 is a diagram illustrating a schematic structure of a battery pack according to an embodiment; 1A to 1C are diagrams for explaining the effects of the structure of the battery pack according to the embodiment. 10 is a diagram illustrating a schematic structure of a battery pack according to a first modified example of the embodiment. FIG. 13 is a diagram illustrating a schematic structure of a battery pack according to a second modified example of the embodiment. FIG.

Below, the embodiments of the present disclosure will be described with reference to the attached drawings. In the embodiments shown below, when the number, quantity, amount, range, etc. of each element is mentioned, the technical idea of the present disclosure is not limited to the mentioned number, unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in the embodiments shown below are not necessarily essential to the technical idea of the present disclosure, unless otherwise specified or clearly specified in principle.

1. Structure of the Battery Pack FIG. 1 is a diagram showing a schematic structure of a battery pack 10 according to an embodiment. The battery pack 10 includes a battery cell 12, a positive electrode side device 14, a negative electrode side device 16, and a case 18. The battery cell 12 does not necessarily need to be multiple, and may be one, but basically, as shown in FIG. 1, there are multiple battery cells 12. The case 18 houses the battery cell 12, the positive electrode side device 14, and the negative electrode side device 16. The battery pack 10 is mounted on a vehicle and supplies power to an electric motor for driving the vehicle. FIG. 1 shows the internal structure of the battery pack 10 when viewed from above the vehicle.

The case 18 has an approximately rectangular parallelepiped shape as an example. More specifically, the case 18 has an approximately rectangular parallelepiped skeletal structure as a basic structure. The case 18 includes a vehicle mounting portion and is fixed to a vehicle structural member via the vehicle mounting portion. Typically, the case 18 is fastened to the vehicle structural member at the vehicle mounting portion using fasteners such as bolts (not shown), but may be fixed by other methods such as welding. In FIG. 1, only the positive electrode side vehicle mounting portion 20 and the negative electrode side vehicle mounting portion 22 on the vehicle front side, which are part of the vehicle mounting portion, are shown. The vehicle mounting portions 20 and 22 are fastened to a vehicle structural member (e.g., a suspension member) on the vehicle front side via fasteners. The vehicle mounting portions 20 and 22 may be formed integrally with the case 18 or may be separate.

In the battery pack 10, the multiple battery cells 12 are formed in a plate shape and arranged in a stacked manner. In the example shown in FIG. 1, the stacking direction of the battery cells 12 is parallel to the vehicle width direction (vehicle left-right direction) D1. However, the stacking direction is not particularly limited, and may be parallel to the vehicle front-rear direction D2, for example. In the example shown in FIG. 1, the multiple battery cells 12 have eight sets of stacks of five battery cells 12 connected in series. These eight sets of stacks are connected in series to form a battery assembly. Each stack of battery cells 12 is fixed to the case 18 via a pair of end plates (not shown).

The positive side device 14 and the negative side device 16 are arranged in the vehicle width direction D1 and are configured as separate units. The positive side device 14 and the negative side device 16 are arranged in the vehicle longitudinal direction D2 near one end of the case 18 (in the example shown in FIG. 1, the end on the vehicle front side) relative to the multiple battery cells 12 and are fixed to the case 18. In the example shown in FIG. 1, the vehicle longitudinal direction D2 corresponds to an example of the "second direction" according to the present disclosure.

The positive side device 14 and the negative side device 16 are, for example, positive side and negative side relays (system main relays). Specifically, the vehicle is equipped with a power control unit (PCU) including an inverter to control the power supplied from the battery pack 10 to the electric motor. The positive side and negative side relays 14, 16 are disposed between the battery assembly of the multiple battery cells 12 and the PCU on the positive side and negative side, respectively. In the example shown in FIG. 1, the vehicle width direction D1 corresponds to an example of the "first direction" according to the present disclosure.

The case 18 of this embodiment includes a first skeletal structural member 24, a second skeletal structural member 26, a positive electrode side skeletal structural member 28, and a negative electrode side skeletal structural member 30. In the following description, the end wall of the case 18 on the side of the one end (i.e., the end toward the front of the vehicle) is referred to as an end wall 32. The end wall of the case 18 located on the opposite side of the one end in the vehicle longitudinal direction D2 (i.e., the rear side of the vehicle) is referred to as an end wall 34. The end walls 32 and 34 are also included in the skeletal structural members that form the skeleton of the case 18. In the example shown in FIG. 1, the end walls 32 and 34 extend along the vehicle width direction D1.

The second skeletal structural member 26 is disposed between the positive and negative devices 14, 16 and the plurality of battery cells 12 (battery assembly), and extends along the vehicle width direction D1 to form the skeleton of the case 18.

The first skeletal structural member 24 extends in the vehicle longitudinal direction D2 between the positive electrode side device 14 and the negative electrode side device 16, and is formed to connect between the end wall 32 on the one end side and the "skeletal portion S" of the case 18. In the example shown in FIG. 1, the second skeletal structural member 26 corresponds to the skeletal portion S (the "skeletal portion" according to the present disclosure). In other words, the first skeletal structural member 24 connects between the end wall 32 and the second skeletal structural member 26.

In the example shown in FIG. 1, the end wall 34 located on the opposite side of the end wall 32 also corresponds to an example of the skeleton portion S. That is, the first skeleton structural member 24 connects the end wall 32 and the end wall 34. In other words, in the structural example shown in FIG. 1, the first skeleton structural member 24 connects the end wall 32 and the second skeleton structural member 26, and is extended in the vehicle fore-and-aft direction D2 so as to also connect the second skeleton structural member 26 and the end wall 34.

By providing the first and second skeletal structural members 24, 26, when viewed from above the vehicle (i.e., as shown in FIG. 1), a skeletal structure can be formed so that the positive electrode side device 14 is surrounded by the outer wall (including the end wall 32) of the case 18 and the first and second skeletal structural members 24, 26. The same is true for the negative electrode side device 16.

In addition, in the example shown in FIG. 1, an additional skeletal structural member 36 is provided between each of the four adjacent stacks of battery cells 12 arranged in the vehicle longitudinal direction. Each skeletal structural member 36 extends along the vehicle width direction D1, similar to the second skeletal structural member 26, to form a skeleton. Therefore, each skeletal structural member 36 can be said to correspond to another example of the skeletal portion S described above.

More specifically, the positive side vehicle mounting portion 20 has a first fixed point P1 with the vehicle at a position away from the end wall 32 in the vehicle longitudinal direction D2 on the side of the positive side device 14 in the vehicle width direction D1. The positive side skeletal structural member 28 extends along the vehicle longitudinal direction D2 with a straight line L1 that passes through the first fixed point P1 when viewed from above the vehicle and is parallel to the vehicle longitudinal direction D2 as its central axis, and is formed to connect between the end wall 32 and the second skeletal structural member 26. The positive side device 14 is formed and arranged in a space surrounded by the outer wall (including the end wall 32) of the case 18 and the first and second skeletal structural members 24, 26 so as to avoid the positive side skeletal structural member 28.

Similarly, the negative side vehicle mounting portion 22 has a second fixed point P2 with the vehicle at a position away from the end wall 32 in the vehicle longitudinal direction D2 on the side of the negative side device 16 in the vehicle width direction D1. The negative side skeletal structural member 30 extends along the vehicle longitudinal direction D2 with a straight line L2 that passes through the second fixed point P2 when viewed from above the vehicle and is parallel to the vehicle longitudinal direction D2 as a central axis, and is formed to connect between the end wall 32 and the second skeletal structural member 26. The negative side device 16 is formed and arranged in a space surrounded by the outer wall of the case 18 and the first and second skeletal structural members 24, 26 so as to avoid the negative side skeletal structural member 30. The case 18 does not necessarily have to have both the positive side vehicle mounting portion 20 and the negative side vehicle mounting portion 22, and may have only one of them.

2. Effects Fig. 2 is a diagram for explaining the effects of the structure of the battery pack 10 according to the embodiment. More specifically, Fig. 2 shows only the structure around the positive electrode side device 14 and the negative electrode side device 16 in the battery pack 10. Fig. 2 also shows a situation in which a large impact load caused by a collision of the front part of the vehicle acts on the battery pack 10 via the negative electrode side vehicle mounting part 22, as an example.

In an example that does not have the first skeletal structural member 24, if an impact load such as that shown in FIG. 2 is input to the negative vehicle mounting portion 22, the case 18 may be crushed so that the end walls 32 move toward the rear of the vehicle on both the positive device 14 side and the negative device 16 side, and both the positive device 14 and the negative device 16 may be damaged. As a result, there is a concern that an electrical short circuit may occur between the positive device 14 and the negative device 16.

In contrast, the battery pack 10 of this embodiment includes the first skeletal structural member 24 disposed between the positive side device 14 and the negative side device 16, as described above. The first skeletal structural member 24 extends along the vehicle longitudinal direction D2 (second direction) and connects the end wall 32 and the skeletal portion S of the case 18. As a result, when a large input is applied to the negative side vehicle mounting portion 22 from the vehicle longitudinal direction D2 as in the example shown in FIG. 2, the case 18 is deformed as follows. That is, since the first skeletal structural member 24 functions as a reinforcing member, the case 18 is deformed such that a portion of the end wall 32 located on the negative side device 16 side with respect to the connection point P3 between the end wall 32 and the first skeletal structural member 24 in the vehicle width direction D1 (first direction) falls toward the negative side device 16 like a seesaw with the connection point P3 as a fulcrum. Therefore, only the negative side device 16 is damaged, and the case 18 is less likely to deform in a way that would crush the positive side device 14. In other words, the impact on the positive side device 14 is mitigated, making it easier to protect the positive side device 14. This is also true in the case where an impact load is input to the positive side vehicle mounting portion 20, as opposed to the example shown in FIG. 2, in which only the positive side device 14 is damaged, and the negative side device 16 is more easily protected. In other words, the resistance of the battery pack 10 to impacts can be improved.

As described above, by providing the first skeletal structural member 24, when an impact load is input to the case 18 on the positive side device 14 side or the negative side device 16 side from the vehicle front-rear direction D2, it is possible to make it difficult for damage to occur to both the positive side device 14 and the negative side device 16. In this way, according to the structure of the battery pack 10, it is possible to suppress electrical short circuits between the positive side device 14 and the negative side device 16 with a simple structure.

The above-mentioned effect of using the first skeletal structural member 24 can be obtained even without the second skeletal structural member 26. Furthermore, the second skeletal structural member 26 extending in the vehicle width direction D1 can form a skeletal structure surrounding each of the positive side device 14 and the negative side device 16 in cooperation with the outer wall (including the end wall 32) of the case 18 and the first skeletal structural member 24. This makes it possible to effectively suppress deformation of the case 18 located around the positive side device 14 or negative side device 16 that receives the above-mentioned impact load input from the vehicle longitudinal direction D2.

1, the first skeletal structural member 24 is connected (extended) to the end wall 34 opposite to the end wall 32 that receives the input of the impact load. As a result, compared to an example in which the first skeletal structural member 44 extends only to the second skeletal structural member 26 as in the example shown in FIG. 3 described later, the first skeletal structural member 24, to which the input of the impact load from the vehicle longitudinal direction D2 (the vehicle front side in FIG. 1) acts, can be received using not only the second skeletal structural member 26 but also the end wall 34. That is, the first skeletal structural member 24 can be more sufficiently prevented from moving toward the rear side of the vehicle due to the input. As a result, the deformation of the case 18 (mainly the end wall 32) caused by the input can be more effectively prevented from extending to the positive side device 14 or the negative side device 16 on the non-input side. In addition, in the example shown in FIG. 1, a skeletal structural member 36 extending in the vehicle width direction D1 is provided between the stacks of battery cells 12 adjacent to each other in the vehicle longitudinal direction D2. The first skeletal structural member 24 is also connected to these skeletal structural members 36, which correspond to the skeletal portion S. Therefore, by also utilizing the skeletal structural members 36, a structure is obtained that can more fully support the first skeletal structural member 24 against the above-mentioned input.

Furthermore, the case 18 is provided with a positive electrode side skeletal structural member 28 and a negative electrode side skeletal structural member 30. This allows the end wall 32 to be supported at a position where the above-mentioned impact load from the vehicle longitudinal direction D2 acts, so that deformation of the case 18 located around the positive electrode side device 14 or the negative electrode side device 16 that receives the input of the impact load can be more effectively suppressed.

3. Modifications The "first skeletal structural member" according to the present disclosure may be configured, for example, as follows. FIG. 3 is a diagram that shows a schematic structure of a battery pack 40 according to a first modification of the embodiment. The case 42 of the battery pack 40 shown in FIG. 3 includes a first skeletal structural member 44. The first skeletal structural member 44 is configured to connect only between the end wall 32 and the second skeletal structural member 26. That is, the end of the first skeletal structural member 44 in the vehicle longitudinal direction D2 is supported by the second skeletal structural member 26 (skeletal portion S). Therefore, even in such a configuration example, the second skeletal structural member 26 can receive the impact load acting on the first skeletal structural member 24 from the vehicle longitudinal direction D2, and therefore, an effect of suppressing an electrical short circuit between the positive electrode side device 14 and the negative electrode side device 16 can be obtained.

Figure 4 is a diagram showing a schematic structure of a battery pack 50 according to a second modified embodiment. The case 52 of the battery pack 50 shown in Figure 4 has a first skeletal structural member 24, similar to the case 18 shown in Figure 1, but unlike the case 18, does not have a second skeletal structural member 26 or a skeletal structural member 36. Even in this configuration example, the end wall 34 (skeletal portion S) alone can withstand the impact load acting on the first skeletal structural member 24 from the vehicle longitudinal direction D2, thereby achieving the effect of suppressing electrical short circuits between the positive side device 14 and the negative side device 16.

In addition, in an example having a skeletal structural member 36 disposed between stacks of adjacent battery cells 12, such as the examples shown in Figures 1 and 3 above, the "first skeletal structural member" according to the present disclosure may be configured to connect to a skeletal structural member 36 corresponding to another example of the "skeletal portion S" instead of the end wall 34 or the second skeletal structural member 26.

In the example shown in Figures 1 to 4, the positive side device 14 and the negative side device 16 are disposed near the end wall 32 on the front side of the vehicle. However, instead of such an example, the "positive side device" and the "negative side device" according to the present disclosure may be disposed, for example, near the end wall of the case on the rear side of the vehicle. According to such an example, it is possible to obtain the effect of suppressing an electrical short circuit between the positive side device and the negative side device in response to the input of an impact load from the rear side of the vehicle.

Furthermore, in the "battery pack" disclosed herein, the "first direction" is not limited to the vehicle width direction D1, and therefore the "second direction" is not limited to the vehicle front-rear direction.

10, 40, 50 Battery pack 12 Battery cell 14 Positive electrode side device 16 Negative electrode side device 18, 42, 52 Battery pack case 20 Positive electrode side vehicle mounting portion 22 Negative electrode side vehicle mounting portion 24, 44 First skeletal structural member 26 Second skeletal structural member 28 Positive electrode side skeletal structural member 30 Negative electrode side skeletal structural member 32, 34 End wall 36 Skeletal structural member

Claims (5)

A battery pack to be mounted on a vehicle,
One or more battery cells;
A positive electrode side device and a negative electrode side device arranged along a first direction and separately configured,
a case that accommodates the one or more battery cells, the positive electrode side device, and the negative electrode side device;
Equipped with
the positive electrode side device and the negative electrode side device are disposed near one end of the case with respect to the one or more battery cells in a second direction perpendicular to the first direction when viewed from above the vehicle,
the case includes a first skeletal structural member extending along the second direction between the positive electrode side device and the negative electrode side device and formed to connect between an end wall of the case on the one end side and a skeleton portion of the case ,
the skeleton portion is a second skeleton structural member that is disposed between the positive electrode side device and the negative electrode side device and the one or more battery cells, and extends along the first direction to form a skeleton of the case,
the battery pack further includes a positive electrode side vehicle attachment portion having a first fixing point with the vehicle at a position separated in the second direction from an end wall of the case on the one end side on a side of the positive electrode side device in the first direction,
the case extends along the second direction with a central axis that is a straight line that passes through the first fixing point and is parallel to the second direction when viewed from above the vehicle, and includes a positive electrode side skeletal structural member formed to connect between an end wall of the case on the one end side and the second skeletal structural member . A battery pack to be mounted on a vehicle,
One or more battery cells;
A positive electrode side device and a negative electrode side device arranged along a first direction and separately configured,
a case that accommodates the one or more battery cells, the positive electrode side device, and the negative electrode side device;
Equipped with
the positive electrode side device and the negative electrode side device are disposed near one end of the case with respect to the one or more battery cells in a second direction perpendicular to the first direction when viewed from above the vehicle,
the case includes a first skeletal structural member extending along the second direction between the positive electrode side device and the negative electrode side device and formed to connect between an end wall of the case on the one end side and a skeleton portion of the case,
the skeleton portion is a second skeleton structural member that is disposed between the positive electrode side device and the negative electrode side device and the one or more battery cells, and extends along the first direction to form a skeleton of the case ,
the battery pack further includes a negative electrode side vehicle mounting portion having a second fixing point with the vehicle at a position away from the end wall of the case on the one end side in the second direction on a side of the negative electrode side device in the first direction,
The case includes a negative electrode side skeletal structural member that extends along the second direction with a central axis that is a straight line that passes through the second fixing point and is parallel to the second direction when the vehicle is viewed from above, and that is formed to connect between an end wall of the case on the one end side and the second skeletal structural member.
A battery pack characterized by: A battery pack to be mounted on a vehicle,
One or more battery cells;
A positive electrode side device and a negative electrode side device arranged along a first direction and separately configured,
a case that accommodates the one or more battery cells, the positive electrode side device, and the negative electrode side device;
Equipped with
the positive electrode side device and the negative electrode side device are disposed near one end of the case with respect to the one or more battery cells in a second direction perpendicular to the first direction when viewed from above the vehicle,
the case includes a first skeletal structural member extending along the second direction between the positive electrode side device and the negative electrode side device and formed to connect between an end wall of the case on the one end side and a skeleton portion of the case,
the skeleton portion is a second skeleton structural member that is disposed between the positive electrode side device and the negative electrode side device and the one or more battery cells, and extends along the first direction to form a skeleton of the case,
the first skeletal structural member extends in the second direction to connect between the second skeletal structural member and an end wall of the case located on an opposite side to the one end in the second direction,
the battery pack further includes a positive electrode side vehicle attachment portion having a first fixing point with the vehicle at a position separated in the second direction from an end wall of the case on the one end side on a side of the positive electrode side device in the first direction,
the case extends along the second direction with a central axis that is a straight line that passes through the first fixing point and is parallel to the second direction when viewed from above the vehicle, and includes a positive electrode side skeletal structural member formed to connect between an end wall of the case on the one end side and the second skeletal structural member . A battery pack to be mounted on a vehicle,
One or more battery cells;
A positive electrode side device and a negative electrode side device arranged along a first direction and separately configured,
a case that accommodates the one or more battery cells, the positive electrode side device, and the negative electrode side device;
Equipped with
the positive electrode side device and the negative electrode side device are disposed near one end of the case with respect to the one or more battery cells in a second direction perpendicular to the first direction when viewed from above the vehicle,
the case includes a first skeletal structural member extending along the second direction between the positive electrode side device and the negative electrode side device and formed to connect between an end wall of the case on the one end side and a skeleton portion of the case,
the skeleton portion is a second skeleton structural member that is disposed between the positive electrode side device and the negative electrode side device and the one or more battery cells, and extends along the first direction to form a skeleton of the case,
the first skeletal structural member extends in the second direction to connect between the second skeletal structural member and an end wall of the case located on an opposite side to the one end in the second direction,
the battery pack further includes a negative electrode side vehicle mounting portion having a second fixing point with the vehicle at a position away from the end wall of the case on the one end side in the second direction on a side of the negative electrode side device in the first direction,
The case includes a negative electrode side skeletal structural member that extends along the second direction with a central axis that is a straight line that passes through the second fixing point and is parallel to the second direction when the vehicle is viewed from above, and that is formed to connect between an end wall of the case on the one end side and the second skeletal structural member.
A battery pack characterized by: The first direction is a width direction of the vehicle,
5. The battery pack according to claim 1 , wherein the second direction is a front-rear direction of the vehicle .

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