Battery pack

Abstract

To provide a technique for cutting off a circuit without causing relative displacement of a battery module when an impact is applied to a battery pack.SOLUTION: A battery pack comprises: a first connector located at an end of a first cable inside a battery case; a first fixing member which fixes the first connector to a first contact on the battery case; a second connector located at an end of a second cable inside the battery case; and a second fixing member which fixes the second connector to a second contact on the battery case. The first contact is disposed closer to a side portion of the battery case than the second contact. The first connector and the second connector are attachably / detachably connected to each other. The first connector is disposed farther from the side portion than the second connector.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a battery pack including a battery case in which a battery module is stored.

Background Art

[0002] In Patent Document 1, a battery device is disclosed. The battery device includes a connection member that electrically connects battery modules fixed in a case and can disconnect the connection between the battery modules when the relative positions of the battery modules change.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to Patent Document 1, when an impact is applied to the battery device, the circuit is interrupted by the relative movement of the battery modules. However, since the relative movement of the battery modules is only an indirect behavior caused by the impact, such a mechanism lacks certainty and has a high risk.

[0005] One object of the present disclosure is to provide a technique for interrupting a circuit without causing relative movement of battery modules when an impact acts on a battery pack.

Means for Solving the Problems

[0006] A first aspect relates to a battery pack including a battery case in which a battery module is stored. The battery pack includes a first connector present at an end of a first cable in the battery case, and a first fixing member that fixes the first connector to a first contact point on the battery case, and A second connector present at an end of a second cable within the battery case, and a second fixing member that fixes the second connector to a second contact point on the battery case are provided. The first contact point is arranged closer to the side portion of the battery case than the second contact point, the first connector and the second connector are detachably connected, and the first connector is arranged farther from the side portion than the second connector.

[0007] A second aspect relates to a battery pack including a battery case in which a battery module is stored. The battery pack includes a first connector present at an end of a first cable within the battery case, a first fixing member that connects the first connector and a first contact point on the battery case, a second connector present at an end of a second cable within the battery case, and a second fixing member that connects the second connector and a second contact point on the battery case are provided. The first connector and the second connector are detachably connected, and when a side portion of the battery case is deformed by a predetermined amount or more toward the inside of the battery case, the connection between the first connector and the second connector is configured to be disconnected.

Advantages of the Invention

[0008] According to the present disclosure, the battery pack is configured such that when a side portion of the battery case is deformed, the connection between the first connector and the second connector is disconnected. Since there is no relative movement of the battery module, it can be said that the battery pack has a more reliable circuit interruption mechanism.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0011] 1. Overview of the battery pack The battery pack 1 shown in the present disclosure is typically used as a power source for electric vehicles (BEV, PEV, HEV, etc.). FIG. 1 is a schematic diagram showing the whole of the battery pack 1 mounted on an electric vehicle. The x-axis direction in the figure corresponds to the forward direction of the electric vehicle. The y-axis direction corresponds to the left direction as seen from the driver sitting in the driver's seat of the electric vehicle, and the z-axis direction corresponds to the upward direction of the electric vehicle. The battery pack 1 includes a battery case 10 and battery modules. The battery modules are stored in the battery case 10. The battery module is an aggregate formed by connecting a plurality of battery cells. The battery cell is a rechargeable secondary battery, for example, a lithium-ion secondary battery. The battery modules are connected to each other by cables. A metal such as an aluminum alloy or steel is used for the battery case 10. The body of the electric vehicle is located outside the battery case 10. Note that the installation direction of the battery pack 1 shown in the drawings is an example, and the actual installation direction of the battery pack 1 is not limited to that shown.

[0012] Generally, in order to drive an electric vehicle, a voltage of about 400V is required. In order to ensure such a high-voltage output, battery modules, which are aggregates of battery cells, are formed, and further, the battery modules are connected to each other.

[0013] In the example of FIG. 1, the battery pack 1 includes a first battery module 20A and a second battery module 20B. Although an actual electric vehicle is equipped with a larger number of battery modules, in this embodiment, the description will focus on the relationship between these two battery modules. A first cable 21A is connected to the first battery module 20A. A second cable 21B is connected to the second battery module 20B. The first cable 21A and the second cable 21B are connected in the circuit connection unit 40, forming a circuit from the first battery module to the second battery module. The circuit connection unit 40 also has a function of disconnecting the connection between the cables and interrupting the circuit when a load acts on the battery pack 1 (details will be described later). Note that as long as it is a connection between cables within the battery case 10, the circuit connection unit 40 is applicable even if it is not a connection between battery modules. For example, the circuit connection unit 40 may be provided midway along the wiring extending from a certain battery module toward the outside of the battery case 10.

[0014] 1-1. Circuit Connection Unit FIG. 2 is a schematic diagram showing the configuration of the circuit connection unit 40. (A) in FIG. 2 is a yz cross-sectional view showing the overall configuration of the circuit connection unit 40 and a perspective view from the z direction. The first cable 21A is provided with a first connector 22A at its end. The first connector 22A is fixed to the first contact 11A on the battery case 10 by the first fixing member 30A. Similarly, the second cable 21B is provided with a second connector 22B at its end. The second connector 22B is fixed to the second contact 11B on the battery case 10 by the second fixing member 30B. The first fixing member 30A and the second fixing member 30B extend vertically from the contacts on the battery case 10. Also, the battery case 10 includes a bottom portion 10B where the battery module is installed and a side portion 10A intersecting the bottom portion 10B. Typically, the side portion 10A extends in a direction perpendicular to the bottom portion 10B.

[0015] In this embodiment, the first connector 22A, the first fixing member 30A, and the first cable 21A are referred to as the first connection unit 40A. Similarly, the second connector 22B, the second fixing member 30B, and the second cable 21B are referred to as the second connection unit 40B. That is, the circuit connection unit 40 includes the first connection unit 40A and the second connection unit 40B. (B) in FIG. 2 shows the first connection unit 40A highlighted. On the other hand, the second connection unit 40B is shown by a dashed line. Conversely, in (C) of FIG. 2, the second connection unit 40B is highlighted while the first connection unit 40A is shown by a dashed line.

[0016] The first contact point 11A is located closer to the side portion 10A of the battery case 10 than the second contact point 11B. In the example of FIG. 2, the first contact point 11A is located on the side portion 10A of the battery case 10, and the second contact point 11B is located on the bottom portion 10B of the battery case 10. That is, it can be said that the first contact point 11A is closer to the side portion 10A than the second contact point 11B. However, the positions of the first contact point 11A and the second contact point 11B are not limited to the example shown in FIG. 2. Other configuration examples will be described later.

[0017] The first connector 22A and the second connector 22B are detachably connected. For example, the first connector 22A is in the form of a socket having holes for receiving pins, and the second connector 22B is in the form of a plug having pins. The connection at this time is in a form in which the pins and the pin receiving holes are engaged. The first connector 22A is arranged at a position farther from the side portion 10A than the second connector 22B. Furthermore, it is desirable that the connection portion 23A in the first connector 22A that engages with the second connector 22B be installed so as to face the side portion 10A. (The reason will be described later.)

[0018] 2. Problems and Effects As described above, electric vehicles are equipped with a power source of about 400V. When such a high voltage is generated, if the battery is damaged or deformed due to an external impact, a short circuit may occur, leading to ignition. In an electric vehicle equipped with a large-capacity battery, there is also a great concern that local ignition may chain between the batteries and develop into a large-scale fire. Therefore, it can be said that a mechanism for interrupting the high-voltage circuit during an impact is essential for safety management. As one such mechanism, there is a mechanism that detects a collision with a collision sensor or the like and cuts off the circuit, but there is a concern that the circuit cannot be cut off unless the collision sensor itself operates normally.

[0019] As another mechanism for interrupting the circuit during an impact, there is a method of physically separating the cable connector. For example, in Patent Document 1, a structure is shown in which some battery modules are movably accommodated, and the circuit is interrupted by the relative movement of the battery modules during an impact.

[0020] However, the mechanism based on the relative movement of the battery modules has the following problems. First, since the relative movement of the battery modules is only an indirect behavior caused by an impact, there is a concern that it may not operate properly when it should operate. Second, there is also a possibility that it may operate even when the battery modules move relative to each other due to an impact during sudden braking or the like. That is, there is a concern that it may malfunction when it should not operate. Third, since a heavy object such as a battery module moves, there is a possibility that the circuit interruption mechanism itself may be damaged and stop functioning. Thus, it can be said that the mechanism for interrupting the circuit by the relative movement of the battery modules lacks certainty and has a high risk.

[0021] In the battery pack 1 shown in the present disclosure, since it does not involve the relative movement of the battery modules, it can be said that it is equipped with a more reliable circuit interruption mechanism. The operation process of the circuit interruption mechanism is shown below. Here, it is assumed that a load (impact) acts from the side portion 10A of the battery case 10 toward the inside of the battery case 10.

[0022] FIG. 3 is a schematic diagram showing the state of the circuit connection unit 40 before and after a load acts on the battery pack 1. (A) in FIG. 3 is a diagram showing the state before the load acts, which has the same configuration as (A) in FIG. 2, but is reproduced here for easier comparison of the states before and after the load acts. (B) in FIG. 3 shows the behavior of the circuit connection unit 40 when the load acts. Due to the applied load, the side portion 10A deforms toward the inside of the battery case 10. As described above, the first contact 11A is located closer to the side portion 10A of the battery case 10 than the second contact 11B (the first contact 11A is on the side portion 10A and the second contact 11B is on the bottom portion 10B). Therefore, the first connection unit 40A tries to move toward the inside of the battery case 10 at a timing earlier than the second connection unit 40B. As described above, the first connector 22A and the second connector 22B are detachably connected, and the first connector 22A is located farther from the side portion 10A than the second connector 22B. With such a configuration, the connection between the first connector 22A and the second connector 22B is disconnected and pulled apart. In other words, the load that deforms the side portion 10A is transmitted as a force that pulls apart the two connectors, thereby cutting off the circuit.

[0023] Furthermore, it is preferable that the connection portion 23A in the first connector 22A that fits with the second connector 22B is installed so as to face the side portion 10A. This is because in this case, the load that deforms the side portion 10A of the battery case 10 is transmitted more efficiently as a force that pulls apart the two connectors than when the connection portion 23A faces another direction.

[0024] In other words, the battery pack 1 includes a circuit connection unit 40, and the circuit connection unit 40 is configured such that when the side portion 10A of the battery case 10 deforms by a predetermined amount or more toward the inside of the battery case 10, the connection between the first connector 22A and the second connector 22B is disconnected. The connection strength between the connectors, the rigidity of each fixing member, the position of each contact, etc. are adjusted so that such a mechanism is exhibited.

[0025] 3. Modification In order for the effect described in Section 2 to be exerted, it is not necessary to have the same configuration as that shown in (A) in FIG. 3. Modified examples capable of exerting the same effect are shown below.

[0026] 3-1. First Modified Example FIG. 4 is a schematic diagram showing a first modified example in the circuit connection unit 40. Both the first contact 11A and the second contact 11B are provided on the bottom 10B. The first fixing member 30A rises from the first contact 11A along the z-axis, bends at a certain height, extends in the y-axis direction, and reaches the first connector 22A.

[0027] When the side portion 10A deforms due to a load, the first connection unit 40A closer to the side portion 10A tends to move at an earlier timing than the second connection unit 40B. This mechanism itself is the same as the example in FIG. 3. Therefore, a force is generated to separate the first connector 22A and the second connector 22B, the connection is disconnected, and the circuit is interrupted.

[0028] In this case, as shown in FIG. 4, it is desirable to set the position of the first contact 11A higher than the position of the second contact 11B. When the first contact 11A is at the bottom 10B-1 and the second contact is at the bottom 10B-2 (lower in height than the bottom 10B-1), the transition portion 10C receives the load and deforms greatly, absorbing the impact energy. Therefore, the second connection unit 40B is less likely to be affected by the deformation of the side portion 10A. On the other hand, the first connection unit 40A is more directly affected by the deformation of the side portion 10A and tends to move, so a force is more likely to be generated to separate the first connector 22A and the second connector 22B. As a result, the connection is more likely to be disconnected, and the circuit is more surely interrupted.

[0029] 3-2. Second Modified Example FIG. 5 is a schematic diagram showing a second modification example in the circuit connection unit 40. The first contact 11A exists on the side portion 10A-1, and the second contact exists on another side portion 10A-2 different from the side portion 10A-1. In this case, the circuit interruption mechanism functions with respect to both the load acting from the side portion 10A-1 side and the load acting from the side portion 10A-2 side. (A) in FIG. 5 shows a state where the connection between the first connector 22A and the second connector 22B is disconnected when a load acts from the side portion 10A-1 side. (B) in FIG. 5 shows a state where the connection between the first connector 22A and the second connector 22B is disconnected when a load acts from the side portion 10A-2 side. Such a configuration is effective because the circuit interruption functions with respect to the loads from both sides of the battery case 10.

Description of the reference numerals

[0030] 1: Battery pack, 10: Battery case, 10A: Side portion, 20A: First battery module, 20B: Second battery module, 22A: First connector, 22B: Second connector, 40: Circuit connection unit

Claims

1. A battery pack including a battery case in which a battery module is stored, a first connector present at an end of a first cable within the battery case, a first fixing member for fixing the first connector to a first contact point on the battery case, a second connector present at an end of a second cable within the battery case, and a second fixing member for fixing the second connector to a second contact point on the battery case is provided, wherein the first contact point is disposed closer to a side portion of the battery case than the second contact point, the first connector and the second connector are detachably connected, and the first connector is disposed farther from the side portion than the second connector battery pack.

2. The battery pack according to claim 1, wherein the first contact point is present on the side portion battery pack.

3. The battery pack according to claim 2, wherein the second contact point is present on another side portion different from the side portion battery pack.

4. The battery pack according to any one of claims 1 to 3, wherein a connection portion within the first connector that fits with the second connector is installed so as to face the side portion battery pack.

5. A battery pack including a battery case in which a battery module is stored, a first connector present at an end of a first cable within the battery case, a first fixing member connecting the first connector and a first contact point on the battery case, a second connector present at an end of a second cable within the battery case, and a second fixing member connecting the second connector and a second contact point on the battery case is provided, the first connector and the second connector are detachably connected, when a side portion of the battery case is deformed by a predetermined amount or more toward the inside of the battery case, the connection between the first connector and the second connector is configured to be disconnected battery pack.

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