Battery pack and control device for battery pack

Abstract

This battery pack is provided with: a housing; a battery module housed in the housing and configured by laminating a plurality of cells; a gas duct which is disposed so as to cover the upper surface of the battery module, extends in the lamination direction, and includes a passage part through which gas is guided in the lamination direction upon generation of the gas from the cells and a discharge part which is connected to a downstream end of the passage part and through which the gas is guided to the outside; and a temperature sensor which is disposed at the downstream end of the passage part and which detects the temperature of gas flowing to the discharge part.

Description

Battery pack and battery pack control device

[0001] The present invention relates to a battery pack and a control device for the battery pack.

[0002] In a battery pack in which a battery module consisting of multiple cells is housed in a case, when a thermal chain problem occurs in which the multiple cells generate heat in a chain reaction, it is necessary to detect this and notify the user, etc.

[0003] The technology described in JP2021-150033A discloses a configuration that includes a gas exhaust valve that opens when the internal pressure of the battery pack is higher than a predetermined pressure, and detects a thermal chain reaction when gas is exhausted. However, this configuration has the problem that it cannot detect the occurrence of a thermal chain reaction at the battery module level within the battery pack, and therefore cannot always properly detect the occurrence of a thermal chain reaction.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a battery pack and a battery pack control device that can detect thermal chain reactions between cells on a battery module basis.

[0005] One embodiment of the present invention is applied to a battery pack including: a housing; a battery module housed in the housing and configured by stacking a plurality of cells; a gas duct arranged to cover an upper surface of the battery module, extending in the stacking direction, and including a passage portion for guiding gas generated from the cells in the stacking direction, and an exhaust portion connected to the downstream end of the passage portion for guiding the gas to the outside; and a temperature sensor arranged at the downstream end of the passage portion for detecting the temperature of the gas flowing through the exhaust portion.

[0006] According to the present invention, a temperature sensor is provided at the downstream end of the passage of the gas duct arranged in the battery module, so that when high-temperature gas is generated from the cell due to a thermal chain reaction, the temperature rise caused by the gas can be detected by the temperature sensor, thereby making it possible to detect the occurrence of a thermal chain reaction in a battery module unit at an earlier stage than in the past.

[0007] Fig. 1 is a configuration diagram of a thermal chain reaction detection system according to an embodiment of the present invention. Fig. 2 is a perspective view of a battery module. Fig. 3 is a longitudinal cross-sectional view of the battery module. Fig. 4 is a longitudinal cross-sectional view of a main part of a gas duct. Fig. 5 is a flowchart of a thermal chain reaction detection process performed by a controller. Fig. 6 is an explanatory diagram showing a temperature rise when a thermal chain reaction occurs.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] FIG. 1 is a configuration diagram of a battery control system 1 for a battery pack 2 according to an embodiment of the present invention.

[0010] 1, the battery control system 1 includes a battery pack 2 and a controller 3 that controls the operation of the battery pack 2. The battery control system 1 is mounted on, for example, an electric vehicle or a hybrid vehicle.

[0011] The battery pack 2 is composed of a housing 11 and a plurality of battery modules 10 housed in the housing 11. Fig. 1 shows an example in which four battery modules 10 (10a, 10b, 10c, 10d) are housed in the housing 11.

[0012] The housing 11 is configured to be sealed from the outside air, thereby preventing rainwater and dust from entering the battery pack 2. Note that the battery pack 2 may be configured to send cool air into the battery pack 2 in order to cool the battery modules 10 in the battery pack 2.

[0013] As will be described later with reference to Fig. 4 , the battery module 10 is configured by stacking cells 14 in a row in the longitudinal direction (the left-right direction in Fig. 4 ). In the example shown in Fig. 4 , 24 battery cells are stacked in one battery module 10. The cells 14 are configured by secondary batteries such as lithium-ion batteries.

[0014] Each battery module 10 is provided on its upper surface with a gas duct 20 consisting of a passage portion 142 and an exhaust portion 143. A gas pipe 40 is connected to the exhaust portion 143. In the battery module 10, when gas is generated from a cell 14 due to an abnormality such as a thermal chain reaction, the gas is exhausted to the outside of the battery pack 2 through the gas duct 20 and the gas pipe 40.

[0015] 1 , a gas pipe 40a is connected to the exhaust portion 143 of the battery module 10a. Similarly, a gas pipe 40b is connected to the exhaust portion 143 of the battery module 10b, a gas pipe 40c is connected to the exhaust portion 143 of the battery module 10c, and a gas pipe 40d is connected to the exhaust portion 143 of the battery module 10d. These gas pipes 40 (40a, 40b, 40c, 40d) communicate with the outside of the housing 11.

[0016] In this way, by connecting the gas pipes 40 to each battery module 10, if gas is generated due to a thermal chain reaction, the gas is discharged to the outside of the battery pack 2. Therefore, even if gas is generated inside the battery module 10, the internal pressure of the battery pack 2, which has a sealed structure, can be prevented from becoming higher than necessary.

[0017] Here, a thermal chain reaction of the cells 14 will be described. In a configuration in which a plurality of cells 14 are stacked and housed, such as the battery pack 2, if an abnormality such as a short circuit occurs in a cell 14 and the cell 14 generates heat, gas is generated inside the cell 14 and expands. Furthermore, the heat from this cell 14 may be transferred to other adjacent cells 14, causing a chain reaction of heat generation and gas generation in the cells 14. For this reason, a vehicle equipped with the battery pack 2 is required to detect the occurrence of a thermal chain reaction early and accurately.

[0018] Conventional battery packs are configured to release gas to the outside when the internal pressure of the battery pack increases, triggering the detection of a thermal chain reaction. This configuration makes it impossible to detect a thermal chain reaction on a battery module-by-battery module basis. Furthermore, it takes time for the pressure in the entire battery pack to increase, making it difficult to detect the occurrence of a thermal chain reaction early on.

[0019] In this embodiment, the occurrence of a thermal chain reaction is detected earlier by the configuration described below.

[0020] A temperature sensor 50 for detecting the temperature of gas passing through the passage 142 of the gas duct 20 is provided on the upper surface of one end of the passage 142 of each battery module 10. The temperature sensor 50 is formed of, for example, a thermistor element.

[0021] Each battery module 10 is provided with a voltage sensor harness 21 connected to a voltage sensor (not shown) that detects the voltage of the cells 14, and a temperature sensor harness 51 connected to a temperature sensor 50. The voltage sensor harness 21 and the temperature sensor harness 51 are provided with connectors 22 at their ends. A controller-side harness 24 that is connected to the controller 3 is connected to the connector 22.

[0022] Although not shown, each battery module 10 is also provided with a high-voltage harness for transmitting and receiving power to and from a load external to the battery pack 2 .

[0023] The controller 3 has a microcomputer and a memory, and executes a program stored in the memory by the microcomputer, thereby executing the heat chain detection process described in FIG.

[0024] The controller 3 also receives signals from the voltage sensor and the temperature sensor 50 via the controller-side harness 24 to detect the voltage of the cell 14 and the temperature of the passage 142 of the battery module 10 .

[0025] FIG. 2 is a perspective view of the battery module 10, and FIG. 3 is a vertical cross-sectional view of the battery module 10. As shown in FIG.

[0026] The battery module 10 is configured by stacking a plurality of cells 14 in the longitudinal direction. Fig. 3 shows an example in which 24 cells 14 are stacked, but this number is not necessarily required. The periphery and bottom surfaces of the stacked cells 14 are covered by a case 15. The top surfaces of the cells 14 are covered by a cover 16. The case 15 and cover 16 are formed of a metal such as aluminum.

[0027] The cover 16 includes a lid portion 141 that covers the top surface of the cell 14, and a passage portion 142 that is formed along the longitudinal direction in the center of the lid portion 141 (the center of a cross section perpendicular to the stacking direction of the battery module 10). Furthermore, the passage portion 142 has a cylindrical outlet portion 143 at the downstream end in the gas flow direction, which is one end side of the passage portion 142. The gas pipe 40 is connected to the outlet portion 143.

[0028] The discharge portion 143 is formed to protrude slightly downward from the end of the passage portion 142 of the battery module 10. A temperature sensor 50 is provided at the downstream end of the passage portion 142 and near the discharge portion 143.

[0029] FIG. 4 is a vertical cross-sectional view of the main part of the battery module 10, focusing on the temperature sensor 50.

[0030] The passage portion 142 is formed as a substantially rectangular passage with flat upper and side surfaces, and a recessed portion 144 is formed at the downstream end in the gas flow direction in which the temperature sensor 50 is to be disposed. The recessed portion 144 is formed as a rectangular recess extending from the upper surface of the passage portion 142 toward the interior of the passage portion 142 and does not communicate with the inside of the passage portion 142. The recessed portion 144 is positioned so that its lower surface is higher than half the height of the inner diameter of the passage portion 142, to an extent that it does not affect the gas flow. The temperature sensor 50 is fixed in close contact with the bottom of the recessed portion 144.

[0031] The temperature sensor harness 51 connected to the temperature sensor 50 is disposed on the upper surface of the passage 142. As shown in FIG. 2 , the temperature sensor harness 51 extends from the upper surface of the passage 142 in the stacking direction and extends from the side surface of the passage 142 to the upper surface of the lid 141. The temperature sensor harness 51 is disposed adjacent to the voltage sensor harness 21 on the upper surface of the lid 141 and is connected to the connector 22 together with the voltage sensor harness 21. The connector 22 is a common connector for both the temperature sensor harness 51 and the voltage sensor harness 21.

[0032] 2 and 3, as shown in Fig. 4, a resin cover 17 made of resin is provided on the upper surface of the cover 16 so as to cover the entire cover 16. The temperature sensor harness 51 is disposed between the upper surface of the passage portion 142 and the resin cover 17.

[0033] An open valve 14a is provided on the upper surface of the cell 14. The open valve 14a is configured to open as shown by arrow A in Fig. 4 when the cell 14 generates heat, generating gas inside the cell 14, and the pressure inside the cell 14 reaches or exceeds a predetermined pressure. When the open valve 14a opens, the inside of the cell 14 communicates with the passage 142, and the gas generated in the cell 14 is discharged to the passage 142.

[0034] The gas discharged from the cells 14 is discharged into the passage 142 of the gas duct 20. The gas discharged into the passage 142 flows toward the outlet 143, and is discharged from the outlet 143 to the outside of the battery pack 2 via the gas pipe 40.

[0035] The recessed portion 144 of the passage portion 142 protrudes inward of the passage portion 142. Because the recessed portion 144 protrudes into the passage portion 142, the gas flowing through the passage portion 142 flows around the recessed portion 144 while colliding with a surface 144 a perpendicular to the gas flow direction, and heads toward the discharge portion 143.

[0036] In this way, when gas is generated, the gas flows around recessed portion 144, so that the temperature of the gas is easily transmitted to temperature sensor 50 arranged inside recessed portion 144, and temperature sensor 50 can more reliably detect the temperature increase caused by the gas. Furthermore, recessed portion 144 is made of a metal with a relatively high thermal conductivity, so that the temperature increase caused by the gas is quickly transmitted to temperature sensor 50 via recessed portion 144.

[0037] Note that, because high-temperature gas passes through the gas duct 20, i.e., inside the passage 142 and the exhaust section 143, if the temperature sensor 50 were configured to be placed directly inside the passage 142, there would be a concern that components and structures with sufficient heat resistance to withstand the high-temperature gas would be required, which would increase costs. On the other hand, in this embodiment, the temperature sensor 50 is placed outside the gas duct 20, i.e., on the upper surface of the passage 142, so the heat resistance temperature of the temperature sensor 50 and the temperature sensor harness 51 can be reduced, thereby reducing costs.

[0038] FIG. 5 is a flowchart of the heat chain detection process executed by the controller 3.

[0039] This flowchart is executed at predetermined intervals (for example, every 10 ms) by the controller 3. The controller 3 executes the processing shown in this flowchart in parallel for each of the multiple battery modules 10 (10a, 10b, 10c, 10d) provided in the battery pack 2 as shown in FIG.

[0040] In step S10 , the controller 3 receives a signal from the temperature sensor 50 and acquires the temperature at the downstream end of the gas duct 20 .

[0041] Next, in step S20, the controller 3 determines whether the temperature detected by the temperature sensor 50 has risen by a predetermined temperature or more within a predetermined time.

[0042] Specifically, the temperature detected by the temperature sensor 50 in the previous process is compared with the temperature newly detected by the temperature sensor 50 a predetermined time (e.g., 10 ms) after the previous temperature was detected, and if the difference between these temperatures, i.e., the temperature rise value, is equal to or greater than a predetermined temperature (e.g., 100°C), it is determined that the temperature has risen by the predetermined temperature or more within the predetermined time, and the process proceeds to step S30. If the temperature has not risen by the predetermined temperature or more within the predetermined time, the process according to this flowchart is temporarily terminated, and the process returns to other processes.

[0043] If step S20 is YES, this indicates that the temperature of the gas in the passage 142 has risen sharply in a short period of time. In this case, in step S30, the controller 3 determines that a thermal chain reaction of the cells 14 has occurred.

[0044] FIG. 6 is an explanatory diagram showing the change in temperature detected by the temperature sensor 50 when a thermal chain reaction occurs in this embodiment.

[0045] 6, the temperature detected by the temperature sensor 50 does not rise above a predetermined temperature within a predetermined time from time t0 to time t1. In this state, the determination in step S20 is NO.

[0046] Here, if the temperature rises rapidly from timing t1 to timing t2 and the temperature rise value Th becomes equal to or greater than a predetermined temperature, the controller 3 determines that a thermal chain reaction has occurred.

[0047] Next, in step S40, the controller 3 performs notification processing. The notification processing is performed, for example, by displaying a warning light or a message on the instrument panel in the driver's seat, or by issuing an alarm or voice warning. This notification processing prompts the driver to receive the service.

[0048] After the process of step S40, the controller 3 returns to other processes.

[0049] By the processing of the flowchart shown in FIG. 5, it is possible to detect a thermal chain reaction for each battery module 10, and to perform appropriate processing (notification processing).

[0050] When the controller 3 detects that a thermal chain reaction has occurred, it can issue a warning to the driver in the notification process of step S40 described above.

[0051] As described above, the battery pack 2 of this embodiment includes the housing 11, the battery module 10 housed in the housing 11 and configured by stacking a plurality of cells 14, and the gas duct 20 arranged to cover the upper surface of the battery module 10, extending in the stacking direction, and including: a passage 142 for guiding gas in the stacking direction when gas is generated from the cells 14; and an exhaust portion 143 connected to the downstream end of the passage 142 for guiding the gas to the outside. A temperature sensor 50 for detecting the temperature of the gas flowing into the exhaust portion 143 is arranged at the downstream end of the passage 142.

[0052] In this configuration, the gas duct 20 of the battery module 10 is provided with a temperature sensor 50, so that when gas is generated from a cell 14, the temperature sensor 50 detects a temperature rise caused by the gas, thereby making it possible to detect the occurrence of a thermal chain reaction in the cells 14 of each battery module 10 more quickly than in conventional methods that detect a thermal chain reaction when the internal pressure of the entire battery pack increases. Furthermore, because the temperature sensor 50 is located at the downstream end of the passage 142 of the gas duct 20, a thermal chain reaction can be detected even if gas is generated in any of the cells 14 in the battery module 10.

[0053] In addition, in this embodiment, the temperature sensor 50 is placed on the upper surface of the passage portion 142 of the gas duct 20, so it does not come into direct contact with the high-temperature gas, and therefore the heat resistance temperature of the temperature sensor 50 can be reduced, thereby reducing costs while maintaining temperature detection accuracy.

[0054] In addition, in this embodiment, the passage portion 142 of the gas duct 20 has a recessed portion 144 recessed from the upper surface toward the inside of the passage portion 142 of the gas duct 20, and the temperature sensor 50 is arranged in the recessed portion 144.

[0055] In this configuration, the gas flowing through the passage portion 142 of the gas duct 20 flows around the recessed portion 144 having a surface 144a perpendicular to the gas flow direction, allowing the temperature sensor 50 to more reliably detect the temperature increase caused by the gas.

[0056] In addition, this embodiment has a voltage sensor that detects the voltage of the cell 14, and a voltage sensor harness 21 connected to the voltage sensor is routed in the stacking direction along the passage portion 142 of the gas duct 20, and a temperature sensor harness 51 connected to the temperature sensor 50 is routed adjacent to the voltage sensor harness 21.

[0057] In this configuration, the temperature sensor harness 51 of the temperature sensor 50 for detecting the gas temperature is routed adjacent to the voltage sensor harness 21 already installed in the battery module 10, so there is no need to provide a new structure for routing the temperature sensor harness 51, thereby reducing costs.

[0058] In addition, in this embodiment, the temperature sensor harness 51 and the voltage sensor harness 21 are connected to the same connector 22, and the connector 22 is connected to a controller side harness 24 that communicates with the controller 3 outside the housing 11.

[0059] In this configuration, the temperature sensor harness 51 of the temperature sensor 50 for detecting the gas temperature is connected to the connector 22 already installed in the battery module 10, so there is no need to provide a new connector to connect the temperature sensor harness 51, thereby reducing costs.

[0060] In addition, this embodiment is equipped with a controller 3 that obtains a temperature rise value from the temperature detected by the temperature sensor 50 and detects the occurrence of a thermal chain reaction of cells 14 based on the obtained temperature rise value, so that a simple configuration can be used to detect a thermal chain reaction of cells 14 on a battery module 10 basis.

[0061] The above describes embodiments of the present invention and their modifications. However, the above embodiments and modifications merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0062] In this embodiment, the temperature sensor 50 is provided in a recessed portion 144 formed by recessing the upper surface of the passage portion 142 of the gas duct 20, but the recessed portion 144 may not be formed and the temperature sensor 50 may be disposed on the upper surface of the passage portion 142. Also, the temperature sensor 50 may be configured to be disposed on the side surface of the passage portion 142.

[0063] In addition, in this embodiment, the temperature sensor 50 is provided at the downstream end of the passage portion 142, but this is not limiting. The temperature sensor 50 may be disposed further downstream in the gas flow direction, i.e., in the discharge portion 143. In this case, a recess for disposing the temperature sensor 50 may be formed in the discharge portion 143.

Claims

1. 1. A battery pack comprising: Housing and a battery module housed in the housing and configured by stacking a plurality of cells; a gas duct arranged to cover an upper surface of the battery module, extending in a stacking direction, and including: a passage portion for guiding gas in the stacking direction when gas is generated from the cell; and an exhaust portion connected to a downstream side of the passage portion for guiding the gas to the outside; a temperature sensor disposed at a downstream end of the passage portion and detecting a temperature of the gas flowing into the discharge portion; Equipped with the passage portion has a recessed portion recessed from the upper surface toward the inside of the passage portion, The temperature sensor is disposed in the recessed portion. Battery pack.

2. 2. The battery pack according to claim 1, The temperature sensor is disposed on an upper surface of the passage portion. Battery pack.

3. 2. The battery pack according to claim 1, a voltage sensor for detecting the voltage of the cell; a voltage sensor harness connected to the voltage sensor is routed along the gas duct in the stacking direction; a temperature sensor harness connected to the temperature sensor is routed adjacent to the voltage sensor harness; Battery pack.

4. 4. The battery pack according to claim 3, The temperature sensor harness and the voltage sensor harness are connected to the same connector, The connector is connected to a harness that communicates with the outside of the housing. Battery pack.

5. The battery pack according to claim 1; a controller that acquires a temperature rise value from the temperature detected by the temperature sensor and detects the occurrence of a thermal chain reaction in the cell based on the acquired temperature rise value; A battery pack control device comprising:

6. 1. A battery pack comprising: Housing and a battery module housed in the housing and configured by stacking a plurality of cells; a gas duct that is disposed so as to cover an upper surface of the battery module, extends in a stacking direction, and integrally includes a passage portion that guides gas generated from the cells in the stacking direction, and an exhaust portion that is connected to a downstream side of the passage portion and guides the gas to the outside; a temperature sensor disposed at a downstream end of the passage portion and detecting a temperature of the gas flowing into the discharge portion; Equipped with Battery pack.