Battery pack

Abstract

To provide a technology for detecting water intrusion into a battery case without providing a liquid leakage sensor for each of a plurality of compartments.SOLUTION: A battery pack that is located below a floor panel of a vehicle includes a plurality of battery modules, a battery case housing the plurality of battery modules, a partition wall that stands up from the bottom of the battery case and divides a space inside the battery case into a plurality of sections, one or more liquid leakage sensors provided in some of the plurality of sections, and a communication path provided along the bottom surface of the battery case and connecting a detection section provided with the liquid leakage sensor and a non-detection section adjacent to the detection section with each other.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a battery pack. [Background technology]

[0002] Patent Document 1 describes a battery pack. This battery pack includes a plurality of battery modules, a battery case that houses the plurality of battery modules, and a leakage sensor that is provided at the bottom of the battery case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-109723 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery pack described above, one or more partitions may be provided inside the battery case, for example, to reinforce the battery case. The partitions are erected from the bottom of the battery case and divide the space inside the battery case into multiple compartments, in which multiple battery modules and other electrical devices are distributed. In such a configuration, for example, if water enters the battery case and enters one compartment, the water will remain in that compartment. Alternatively, if condensation occurs inside the battery case and water droplets form in one compartment, the water droplets will remain in that compartment. Since such water entry and condensation (hereinafter referred to as water entry and the like) can occur in any of the multiple compartments, a leakage sensor must be provided for each of the multiple compartments in order to accurately detect it.

[0005] In view of the above circumstances, this specification provides a technique for detecting water intrusion into a battery case without providing a leakage sensor for each of a plurality of compartments. [Means for solving the problem]

[0006] The technology disclosed in this specification is embodied in a battery pack disposed below a floor panel of a vehicle, the battery pack including: a plurality of battery modules; a battery case accommodating the plurality of battery modules; a partition wall extending from the bottom surface of the battery case and dividing the space within the battery case into a plurality of compartments; one or more liquid leakage sensors provided in some of the compartments; and a communication path provided along the bottom surface of the battery case and connecting a detection compartment in which the liquid leakage sensor is provided to a non-detection compartment adjacent to the detection compartment.

[0007] In the above-described configuration, the multiple compartments include a detection compartment equipped with a liquid leakage sensor and a non-detection compartment adjacent to the detection compartment and not equipped with a liquid leakage sensor. The detection compartment and the non-detection compartment are connected to each other via a communication path. With this configuration, for example, when water intrusion or the like occurs in the detection compartment, the water intrusion or the like can be detected by the liquid leakage sensor installed in the detection compartment. Even when water intrusion or the like occurs in the non-detection compartment, the water can enter the detection compartment through the communication path and be detected by the liquid leakage sensor. In particular, since the battery pack of the present technology is mounted on a vehicle, it is expected that water in the non-detection compartment will quickly move into the detection compartment in response to the vehicle's movement, posture, etc. Therefore, water intrusion or the like into the battery case can be detected without installing a liquid leakage sensor in each of the multiple compartments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle 100 on which a battery pack 10 according to an embodiment is mounted. [Figure 2] 1 is a diagram showing a schematic configuration of a battery pack 10 according to an embodiment, with the upper cover 16 omitted from the illustration. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5]FIG. 4 is a diagram illustrating a communication hole CH formed by a notch 31a of a first partition wall 30a. [Figure 6] 10 is a diagram illustrating that a fifth liquid leakage sensor 36e is disposed in a lowest portion 38 of the lower plate 18. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one embodiment of the present technology, the battery case may have a lower plate that forms a bottom surface. In this case, the lower plate may be provided with a cooling path through which a coolant flows. With this configuration, a cooler is not required inside the battery pack, and the number of components that make up the battery pack can be reduced and the battery pack can be made smaller. Furthermore, even if water leaks into the battery case through the cooling path, the leak can be detected by the liquid leakage sensor.

[0010] In one embodiment of the present technology, the communication path may extend linearly along the front-to-rear direction of the vehicle from the compartment located at the front end to the compartment located at the rear end. In this case, a leakage sensor may be disposed at at least one of the front end and the rear end of the communication path. With this configuration, a relatively small number of leakage sensors can be used to detect water leakage into the battery case.

[0011] In one embodiment of the present technology, the leakage sensor may be disposed at a location on the bottom surface of the battery case that is lowest in the vertical direction of the vehicle. With this configuration, the single leakage sensor can detect water intrusion into the battery case. [Example]

[0012] A battery pack 10 according to an embodiment and a vehicle 100 equipped with the battery pack 10 will be described with reference to the drawings. The vehicle 100 referred to here is an electric vehicle having a motor 106 that drives wheels 104f and 104r, and is typically an electric vehicle (a so-called automobile) that runs on a road. However, some or all of the techniques described in this embodiment can also be adopted in an electric vehicle that runs on a track. Furthermore, the vehicle 100 is not limited to one that is driven and operated by a user, but may be one that is remotely controlled by an external device or one that runs autonomously.

[0013] Here, the directions of the battery pack 10 in the drawings correspond to the directions when the battery pack 10 is mounted on the vehicle 100, i.e., the directions of the vehicle 100. Therefore, the direction FR indicates the front in the longitudinal direction of the vehicle 100, and the direction RR indicates the rear in the longitudinal direction of the vehicle 100. The direction LH indicates the left in the lateral direction of the vehicle 100, and the direction RH indicates the right in the lateral direction of the vehicle 100. The direction UP indicates the upward direction in the vertical direction of the vehicle 100, and the direction DW indicates the downward direction in the vertical direction of the vehicle 100.

[0014] As shown in FIG. 1, a vehicle 100 includes a body 102 and a plurality of wheels 104f, 104r. The body 102 has a passenger compartment 102c, which is a space for carrying passengers. The plurality of wheels 104f, 104r are rotatably attached to the body 102. The plurality of wheels 104f, 104r include a pair of front wheels 104f located at the front of the body 102 and a pair of rear wheels 104r located at the rear of the body 102. The pair of front wheels 104f are arranged coaxially with each other, and the pair of rear wheels 104r are also arranged coaxially with each other. Note that the number of wheels 104f, 104r is not limited to four. Although not particularly limited, the body 102 is made of metal such as steel or aluminum alloy.

[0015] As shown in FIG. 1 , the vehicle 100 further includes a motor 106, a power control unit 108, and a battery pack 10. The motor 106 is a traction motor that drives a pair of rear wheels 104r and is connected to the pair of rear wheels 104r. The power control unit 108 has a built-in DC-DC converter and / or inverter. The battery pack 10 is a power supply device that supplies power to the motor 106. The motor 106 is connected to the battery pack 10 via the power control unit 108. Therefore, the power control unit 108 can control the drive power supplied from the battery pack 10 to the motor 106 and the regenerative power supplied from the motor 106 to the battery pack 10, for example, in response to driving operations by a user.

[0016] The motor 106 is not limited to the pair of rear wheels 104r, but may be configured to drive at least one of the multiple wheels 104f, 104r. The vehicle 100 may further include another prime mover such as an engine instead of or in addition to the motor 106. The vehicle 100 may also include other power supply devices such as a fuel cell unit or a solar panel in addition to the battery pack 10. The vehicle 100 is not limited to the electric vehicle described here, but may also be a hybrid vehicle, a fuel cell vehicle, a solar car, or the like.

[0017] 1, the vehicle body 102 includes a floor panel 110. The floor panel 110 is a plate-like member that forms the bottom surface of the vehicle interior 102c. The battery pack 10 is disposed below and along the floor panel 110.

[0018] Next, the battery pack 10 will be described. As shown in Fig. 2, the battery pack 10 includes a plurality of battery modules 12 and a battery case 14. Each battery module 12 incorporates a plurality of secondary battery cells, and is configured to be repeatedly rechargeable using external power or regenerative power from a motor 106. Each secondary battery cell is, for example, a lithium-ion secondary battery cell. The battery case 14 is a housing member that houses the plurality of battery modules 12.

[0019] As shown in Figures 2 and 3, the battery case 14 includes an upper cover 16 and a lower plate 18. The upper cover 16 is a plate-shaped member that constitutes the battery case 14. The upper cover 16 is provided at the top of the battery case 14 so as to cover the multiple battery modules 12. The lower plate 18 is provided at the bottom of the battery case 14 so as to support the multiple battery modules 12. The upper cover 16 and the lower plate 18 face each other in the vehicle height direction. Therefore, the upper cover 16 constitutes the top surface of the battery case 14, and the lower plate 18 constitutes the bottom surface of the battery case 14.

[0020] The lower plate 18 includes an upper lower plate 20 and a lower lower plate 22. The upper lower plate 20 is a plate-like member. The lower lower plate 22 is a corrugated member, and has multiple grooves 22a formed on its surface facing the upper lower plate 20. Multiple battery modules 12 are arranged on the upper surface of the upper lower plate 20. The lower surface of the upper lower plate 20 faces the upper surface of the lower lower plate 22. As a result, a cooling path is formed between the lower surface of the upper lower plate 20 and the upper surface of the lower lower plate 22 by the multiple grooves 22a formed in the lower lower plate 22. The multiple battery modules 12 can be cooled by circulating a coolant through this cooling path. In this way, the lower plate 18 forms the lower surface of the battery case 14 and can function as a cooler for cooling the multiple battery modules 12. The coolant is water, although not particularly limited thereto. Each of the upper lower plate 20 and the lower lower plate 22 may be made of a single plate-like member, or may be made of a member in which a plurality of plate-like members are joined by welding, etc. Furthermore, the lower plate 18 does not necessarily have to be made of two plates, i.e., the upper lower plate 20 and the lower lower plate 22, but may be made of a single plate.

[0021] As shown in FIGS. 2 and 3 , the battery case 14 further includes a front wall 24, a rear wall 26, and a pair of side walls 28. The front wall 24, the rear wall 26, and the pair of side walls 28 are each a plate-shaped member that constitutes the battery case 14. The front wall 24 extends in the left-right direction at the front of the battery case 14. The rear wall 26 extends in the left-right direction at the rear of the battery case 14. The front wall 24 and the rear wall 26 face each other in the front-rear direction. The pair of side walls 28 extend in the front-rear direction at each end of the battery case 14 and face each other in the left-right direction. Therefore, the front wall 24 constitutes the front surface of the battery case 14, the rear wall 26 constitutes the back surface of the battery case 14, and the pair of side walls 28 constitute a pair of side surfaces of the battery case 14. As a result, the front wall 24, the rear wall 26, and the pair of side walls 28, together with the upper cover 16 and the lower plate 18, form a sealed structure for the battery case 14.

[0022] As shown in FIGS. 2-5, the battery pack 10 further includes a plurality of partition walls 30a, 30b, 30c, and 30d. The partition walls 30a-30d are framework members for reinforcing the battery case 14. Each of the partition walls 30a-30d is provided inside the battery case 14 and extends in the left-right direction. The upper end of each of the partition walls 30a-30d is connected to the upper cover 16 via, for example, a rubber member. The lower end of each of the partition walls 30a-30d extends upright from the lower plate 18. The partition walls 30a-30d include a first partition wall 30a, a second partition wall 30b, a third partition wall 30c, and a fourth partition wall 30d. The first partition wall 30a is located between the front wall 24 and the second partition wall 30b, the second partition wall 30b is located between the first partition wall 30a and the third partition wall 30c, the third partition wall 30c is located between the second partition wall 30b and the fourth partition wall 30d, and the fourth partition wall 30d is located between the third partition wall 30c and the rear wall 26. That is, from front to rear, the first partition wall 30a, the second partition wall 30b, the third partition wall 30c, and the fourth partition wall 30d are arranged in this order.

[0023] As shown in FIGS. 2-5 , the battery pack 10 further includes multiple stopper pairs 32a, 32b, 32c, and 32d. Each stopper pair 32a-32d is a member for fixing the corresponding partition wall 30a-30d to the battery case 14. The multiple stopper pairs 32a-32d include a first stopper pair 32a, a second stopper pair 32b, a third stopper pair 32c, and a fourth stopper pair 32d. One of the first stopper pair 32a is disposed between the first partition wall 30a and one of the side walls 28, and the other of the first stopper pair 32a is disposed between the first partition wall 30a and the other side wall 28. Therefore, the first partition wall 30a is fixed to the pair of side walls 28 by the first stopper pair 32a. Similarly, the second partition 30b is fixed to a pair of sidewalls 28 by a second stopper pair 32b, the third partition 30c is fixed to a pair of sidewalls 28 by a third stopper pair 32c, and the fourth partition 30d is fixed to a pair of sidewalls 28 by a fourth stopper pair 32d.

[0024] Therefore, as shown in FIGS. 2-5 , the space within the battery case 14 is divided into multiple compartments 34a-34e by the multiple partition walls 30a-30d. Specifically, the space within the battery case 14 is divided from the front to the rear into a first compartment 34a, a second compartment 34b, a third compartment 34c, and a fourth compartment 34d. For example, the first compartment 34a houses electrical equipment such as a control device for the battery pack 10, and the second compartment 34b, the third compartment 34c, and the fourth compartment 34d each house a battery module 12. The number of the multiple partition walls 30a-30d is not particularly limited, as long as there is at least one. The number of the multiple stopper pairs 32a-32d can be changed as needed depending on the number of the multiple partition walls 30a-30d. Furthermore, the positions at which the partition walls 30a-30d are disposed are not particularly limited. The shapes of the multiple stopper pairs 32a-32d are also not particularly limited.

[0025] As shown in FIGS. 2-4, the battery pack 10 further includes multiple liquid leakage sensors 36a, 36b, 36c, and 36d. Each of the liquid leakage sensors 36a-36d is capable of detecting water intrusion and other abnormalities. The multiple liquid leakage sensors 36a-36d include a first liquid leakage sensor 36a, a second liquid leakage sensor 36b, a third liquid leakage sensor 36c, and a fourth liquid leakage sensor 36d. The first liquid leakage sensor 36a is provided at the front end of the right side of the first compartment 34a, and the second liquid leakage sensor 36b is provided at the front end of the left side of the first compartment 34a. The third liquid leakage sensor 36c is provided at the rear end of the right side of the fourth compartment 34d, and the fourth liquid leakage sensor 36d is provided at the rear end of the left side of the fourth compartment 34d. In this way, the multiple liquid leakage sensors 36a-36d are provided in some of the multiple sections 34a-34e (i.e., the first section 34a and the fourth section 34d). Note that, hereinafter, the first section 34a and the fourth section 34d in which the liquid leakage sensors 36a-36d are provided will be referred to as detection sections, and the sections adjacent to the detection sections (i.e., the second section 34b and the third section 34c in which the liquid leakage sensors 36a-36d are not provided) will be referred to as non-detection sections. The specific configuration of the liquid leakage sensors 36a-36d is not particularly limited.

[0026] As shown in FIGS. 4 and 5 , each partition wall 30a-30d includes a notch 31a. The notch 31a is provided along the lower plate 18 at both ends facing the pair of sidewalls. Therefore, a first communication hole CH is formed by the notch 31a between the first compartment 34a and the second compartment 34b. Similarly, a second communication hole is formed by the notch between the second compartment 34b and the third compartment 34c, and a third communication hole is formed by the notch 31a between the third compartment 34c and the fourth compartment 34d, although these are not shown. These communication holes CH form a right communication path CR1 on the right side of the battery pack 10, extending linearly in the front-to-rear direction from the first compartment 34a, which is located at the forefront, to the fourth compartment 34d, which is located at the rearmost. This right communication path CR1 extends along the right sidewall 28. Similarly, a left communication path CR2 is formed on the left side of the battery pack 10. The left communication path CR2 extends linearly in the front-to-rear direction from the first compartment 34a, which is located at the forefront in the front-to-rear direction, to the fourth compartment 34d, which is located at the rearmost in the front-to-rear direction. This left communication path CR2 extends along the left sidewall 28. Therefore, each of the communication paths CR1 and CR2 connects the detection compartment and the non-detection compartment to each other on both the left and right sides of the battery pack 10 in the left-to-right direction.

[0027] In the above-described configuration, the multiple compartments 34a-34d include detection compartments (i.e., the first compartment 34a and the fourth compartment 34d) in which the liquid leakage sensors 36a-36d are provided, and non-detection compartments (i.e., the second compartment 34b and the third compartment 34c) adjacent to the detection compartments and in which no liquid leakage sensors are provided. The detection compartments and non-detection compartments are connected to each other via communication paths CR1 and CR2. With this configuration, for example, when flooding or the like occurs in the detection compartments, the flooding or the like can be detected by the liquid leakage sensors 36a-36d provided in the detection compartments. Even when flooding or the like occurs in the non-detection compartments, the water can enter the detection compartments through the communication paths CR1 and CR2, allowing the flooding or the like to be detected by the liquid leakage sensors 36a-36d. In particular, since the battery pack 10 of the present technology is mounted on a vehicle 100, it is expected that water in the non-detection compartments will quickly move into the detection compartments in response to the vehicle's movement, posture, etc. Therefore, it is possible to detect water intrusion into the battery case 14 without providing a leakage sensor 36a-36d for each of the multiple compartments 34a-34d.

[0028] In the above-described configuration, the right communication path CR1 extends in the front-rear direction along the right sidewall 28, and the left communication path CR2 extends in the front-rear direction along the left sidewall 28. With this configuration, for example, when water enters the non-detection section, the water can move in the front-rear direction along the pair of sidewalls 28 and can be guided relatively quickly to the liquid leakage sensors 36a-36d via the communication paths CR1 and CR2.

[0029] In the above-described embodiment, the plurality of leakage sensors 36a-36d are provided on both the front and rear ends of the communication paths CR1 and CR2 on the right and left sides of the battery pack 10. However, the number of the plurality of leakage sensors 36a-36d does not necessarily need to be four; at least one is sufficient. For example, if there are two leakage sensors, one leakage sensor may be provided on the front right end of the first compartment 34a, and the other leakage sensor may be provided on the rear left end of the fourth compartment 34d. In this manner, the plurality of leakage sensors 36a-36d may be provided on at least one of the front and rear ends of the communication paths CR1 and CR2 on at least one of the right and left sides of the battery pack 10.

[0030] In the above-described embodiment, each of the partition walls 30a-30d has a notch 31a formed along the lower plate 18 at both ends facing the pair of sidewalls. However, the notch 31a of each of the partition walls 30a-30d does not necessarily have to be formed at both ends facing the pair of sidewalls. For example, the notch 31a of each of the partition walls 30a-30d may be formed in a portion other than the both ends (i.e., the center) in addition to or instead of both ends in the left-right direction. Even with this configuration, a communication path extending linearly in the front-rear direction from the first compartment 34a to the fourth compartment 34d can be formed in the battery pack 10.

[0031] Furthermore, the communication paths CR1 and CR2 do not necessarily have to be formed by the cutouts 31a in the partition walls 30a-30d. For example, a communication path extending linearly in the front-rear direction from the first section 34a to the fourth section 34d may be formed by providing a bead in the lower plate 18. As described above, the communication paths CR1 and CR2 can be formed by communication holes provided in the partition walls 30a-30d in various configurations.

[0032] As a modification of this embodiment, as shown in Fig. 6, the lower plate 18 of the battery pack 10 may be provided with a location 38 that is lowest in the vertical direction of the vehicle 100 (hereinafter referred to as the lowest portion). In this case, a fifth leakage sensor 36e may be disposed at the lowest portion 38 instead of the four leakage sensors 36a-36d described above. With this configuration, when water or the like enters a certain compartment, it is expected that the water will be guided toward the lowest portion 38 of the lower plate 18. Therefore, water or the like entering the battery case 14 can be detected by a single leakage sensor 36e.

[0033] Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility either alone or in combination. [Explanation of symbols]

[0034] 10: Battery pack 12: Battery module 14: Battery case 16: Upper cover 18: Lower plate 20: Upper lower plate 22: Lower plate 22a: Groove 24: Front wall 26: Rear wall 28: Sidewall 30a-30d: Bulkhead 31a: Notch 32a-32d: Stopper pair 34a-34e: Sections 36a-36e: Leak sensor 38 :Lowest part 100: Vehicle 102: Body 102c: Cabin 104f, 104r: Wheels 106: Motor 108: Power control unit 110: Floor panel CH:Communication hole CR1, CR2: Communication path

Claims

[Claim 1] A battery pack to be mounted on a vehicle, A battery module; Electrical equipment and a battery case that houses the battery module and the electrical device; Equipped with the battery case is disposed below the battery module and the electrical device, and includes a lower plate having a downwardly convex lower surface and a coolant flow path formed therein; The lower plate is a flow path forming portion in which the refrigerant flow path is formed; a non-flow-path forming portion that is disposed at an end portion on a vehicle front side and in which the refrigerant flow path is not formed; Equipped with The electrical device is disposed so as to overlap the non-flow path forming portion in the vertical direction. Battery pack.

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