Battery pack and battery pack control device

Abstract

A battery pack is provided with: a case; a battery module housed in the case and configured by stacking a plurality of unit cells; a gas duct which is provided with a passage part that is disposed so as to cover the upper surface of the battery module, extends in the stacking direction, and guides a gas in the stacking direction when the gas is generated from the unit cells, and a discharge part that is connected to the downstream end of the passage part and guides the gas to the outside; and a temperature sensor which is disposed at the downstream end of the passage part and detects the temperature of the gas flowing to the discharge part.

Description

Technical Field

[0001] This invention relates to battery packs and battery pack control devices. Background Technology

[0002] In a battery pack consisting of a battery module made up of multiple individual cells housed within a casing, it is required to detect and report to users or other parties when a thermal cascade problem occurs where multiple individual cells generate heat in a chain reaction. Summary of the Invention

[0003] The problem the invention aims to solve

[0004] The technology disclosed in JP2021-150033A presents a structure that includes an exhaust valve that opens when the internal pressure of the battery pack is higher than a predetermined pressure, and performs thermal interlock detection when gas is discharged. This structure has the following problem: it cannot detect thermal interlocking occurring at the battery module level within the battery pack, and therefore may not be able to properly detect the occurrence of thermal interlocking.

[0005] The present invention was made in view of the following problem, and its object is to provide a battery pack and a control device for the battery pack capable of detecting thermal interlocks of individual cells at the battery module level.

[0006] Solution for solving the problem

[0007] One embodiment of the present invention is applicable to a battery pack. The battery pack includes: a housing; a battery module housed in the housing, which is constructed by stacking multiple individual cells; a gas conduit having a passage portion and a discharge portion, the passage portion being configured to cover the upper surface of the battery module and extending along the stacking direction to guide gas generated from the individual cells along the stacking direction, the discharge portion being connected to the downstream end of the passage portion and guiding the gas to the outside; and a temperature sensor disposed at the downstream end of the passage portion to detect the temperature of the gas flowing towards the discharge portion.

[0008] The effects of the invention

[0009] According to the present invention, since a temperature sensor is provided at the downstream end of the passage portion of the gas pipe disposed in the battery module, the temperature rise caused by the gas generated from a single cell due to thermal chain reaction can be detected by the temperature sensor. Therefore, the occurrence of thermal chain reaction at the battery module level can be detected at an earlier stage than before. Attached Figure Description

[0010] Figure 1 This is a structural diagram of the thermal interlock detection system according to an embodiment of the present invention.

[0011] Figure 2 This is a 3D view of the battery module.

[0012] Figure 3 This is a longitudinal sectional view of the battery module.

[0013] Figure 4 This is a longitudinal sectional view of the main part of the gas pipeline.

[0014] Figure 5 This is a flowchart of the thermal interlock detection process performed by the controller.

[0015] Figure 6 This is an explanatory diagram showing the temperature rise when a thermal chain occurs. Detailed Implementation

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings and other accompanying documents.

[0017] Figure 1 This is a structural diagram of the battery control system 1 of the battery pack 2 according to an embodiment of the present invention.

[0018] like Figure 1 As shown, the battery control system 1 is configured to include a battery pack 2 and a controller 3 that controls the operation of the battery pack 2. The battery control system 1 is, for example, installed in electric vehicles and hybrid vehicles.

[0019] The battery pack 2 consists of a housing 11 and multiple battery modules 10 housed within the housing 11. Figure 1 An example is shown in which four battery modules 10 (10a, 10b, 10c, 10d) are housed within the housing 11.

[0020] The casing 11 is configured to be airtight relative to external gases. This prevents rainwater and dust from entering the battery pack 2. Alternatively, it can be configured to supply cool air into the battery pack 2 to cool the battery modules 10 inside the battery pack 2.

[0021] For use later Figure 4 As described, the battery module 10 is connected to the single cell 14 in the longitudinal direction ( Figure 4 It is formed by stacking layers in a column (left and right directions). Figure 4 The example shown illustrates a battery module 10 with 24 individual battery cells stacked on top of each other. Each individual cell 14 is composed of a secondary battery, such as a lithium-ion battery.

[0022] Each battery module 10 has a gas conduit 20 consisting of a passage portion 142 and a discharge portion 143 on its upper surface. A gas pipe 40 is connected to the discharge portion 143. In the battery module 10, when gas is generated from the single cell 14 in case of an abnormality such as thermal interlock, the gas is discharged to the outside of the battery pack 2 through the gas conduit 20 and the gas pipe 40.

[0023] exist Figure 1 In the example shown, a gas pipe 40a is connected to the discharge section 143 of battery module 10a. Similarly, a gas pipe 40b is connected to the discharge section 143 of battery module 10b, a gas pipe 40c is connected to the discharge section 143 of battery module 10c, and a gas pipe 40d is connected to the discharge section 143 of battery module 10d. These gas pipes 40 (40a, 40b, 40c, 40d) communicate with the outside of the housing 11.

[0024] By connecting gas pipes 40 to each battery module 10, gas is discharged to the outside of the battery pack 2 in the event of gas generation caused by thermal interlocking. Therefore, even if gas is generated inside the battery module 10, the internal pressure of the battery pack 2, which is a sealed structure, can be prevented from becoming too high as required.

[0025] Here, we will explain the thermal cascading effect of a single battery cell 14. In a structure where multiple single batteries 14 are stacked together, such as in battery pack 2, if a short circuit or other abnormality occurs in a single battery cell 14, causing it to heat up, gas will be generated inside the single battery cell 14 and expand. Moreover, the heat from this single battery cell 14 can be transferred to other adjacent single batteries 14, and sometimes the heating and gas generation of a single battery cell 14 can occur in a cascading manner. Therefore, for vehicles equipped with battery pack 2, it is necessary to detect the occurrence of thermal cascading as early and accurately as possible.

[0026] Traditional battery packs are designed to release gas to the outside when the internal pressure of the battery pack increases, using this as a trigger for thermal chain detection. However, this structure cannot detect thermal chain events at the battery module level. Furthermore, it suffers from the problem that time elapses until the overall pressure of the battery pack rises, making early detection of thermal chain events difficult.

[0027] In this embodiment, the configuration is such that the occurrence of thermal chaining is detected earlier using the structure described below.

[0028] A temperature sensor 50 is provided on the upper surface of one end of the passage portion 142 of each battery module 10 to detect the temperature of the gas passing through the passage portion 142 of the gas pipe 20. The temperature sensor 50 is, for example, composed of a thermistor element.

[0029] Each battery module 10 includes a voltage sensor harness 21 connected to a voltage sensor (not shown) for detecting the voltage of a single battery 14 and a temperature sensor harness 51 connected to a temperature sensor 50. Connectors 22 are provided at the ends of the voltage sensor harness 21 and the temperature sensor harness 51. A controller-side harness 24, which is connected to the controller 3, is connected to the connector 22.

[0030] In addition, although not shown, each battery module 10 also has a high-voltage wiring harness for receiving and transmitting power between itself and an external load of the battery pack 2.

[0031] Controller 3 has a microcomputer and a memory. The microcomputer executes the program stored in the memory to perform the operation. Figure 5 Explanation of thermal interlock detection and processing.

[0032] In addition, the controller 3 receives signals from the voltage sensor and temperature sensor 50 via the controller side wiring harness 24 to detect the voltage of the single battery 14 and the temperature of the passage section 142 of the battery module 10.

[0033] Figure 2 This is a 3D view of battery module 10. Figure 3 This is a longitudinal sectional view of battery module 10.

[0034] The battery module 10 is constructed by stacking multiple individual cells 14 in the longitudinal direction. Figure 3 An example is shown with 24 stacked individual cells 14, but this number is not always required. The stacked individual cells 14 are covered by a housing 15 on their periphery and bottom surface. The top surface of the individual cells 14 is covered by a cover 16. These housings 15 and covers 16 are made of a metal such as aluminum.

[0035] The cover 16 has a cover portion 141 covering the upper surface of the single battery 14 and a passage portion 142 formed along the length direction at the center of the cover portion 141 (the center of the cross section orthogonal to the stacking direction of the battery module 10). At one end of the passage portion 142, i.e. the downstream end in the gas flow direction, there is a cylindrical discharge portion 143 for connecting the gas pipe 40.

[0036] The discharge section 143 is formed protruding slightly downward from the end of the passage section 142 of the battery module 10. A temperature sensor 50 is provided at the downstream end of the passage section 142 and near the discharge section 143.

[0037] Figure 4 This is a longitudinal sectional view of the main part of the battery module 10, centered on the temperature sensor 50.

[0038] The passage portion 142 is formed as a generally rectangular passage with flat surfaces on its upper and side surfaces. A recessed portion 144 for mounting the temperature sensor 50 is formed at its downstream end in the gas flow direction. The recessed portion 144 is rectangular in shape, recessed from the upper surface of the passage portion 142 toward the interior of the passage portion 142, and does not communicate with the inner side of the passage portion 142. The lower surface of the recessed portion 144 is positioned at a height greater than half the height of the inner diameter of the passage portion 142, to a degree that does not affect the gas flow. The temperature sensor 50 is fixed to the bottom of the recessed portion 144 in close contact with the bottom of the recessed portion 144.

[0039] A temperature sensor wiring harness 51, connected to temperature sensor 50, is disposed on the upper surface of the passage portion 142. For example... Figure 2 As shown, the temperature sensor wiring harness 51 extends from the upper surface of the passage portion 142 along the stacking direction, and extends from the side of the passage portion 142 toward the upper surface of the cover portion 141. The temperature sensor wiring harness 51 is disposed on the upper surface of the cover portion 141 adjacent to the voltage sensor wiring harness 21, and is connected to the connector 22 together with the voltage sensor wiring harness 21. The connector 22 is a common connector shared by the temperature sensor wiring harness 51 and the voltage sensor wiring harness 21.

[0040] In addition, although Figure 2 and Figure 3 The middle is omitted, but as Figure 4 As shown, a resin cover 17 made of resin is provided on the upper surface of the cover 16 in a manner that covers the entire cover 16. The temperature sensor wiring harness 51 is disposed between the upper surface of the passage portion 142 and the resin cover 17.

[0041] An opening valve 14a is provided on the upper surface of the single cell 14. The opening valve 14a is configured to release gas inside the single cell 14 when the single cell 14 heats up and the pressure inside the single cell 14 exceeds a predetermined pressure. Figure 4 As indicated by arrow A, the opening valve 14a is open. If the opening valve 14a is open, the interior of the single cell 14 is connected to the passage 142, and the gas generated in the single cell 14 is discharged into the passage 142.

[0042] The gas discharged from the single cell 14 is discharged into the passage 142 of the gas pipe 20. The gas discharged into the passage 142 flows toward the discharge section 143, which serves as the outlet, and is discharged from the discharge section 143 to the outside of the battery pack 2 via the gas pipe 40.

[0043] The recessed portion 144 of the passage portion 142 protrudes inward. As the gas flowing in the passage portion 142 protrudes inward, it collides with the surface 144a orthogonal to the gas flow direction while flowing around the recessed portion 144 and flows toward the discharge portion 143.

[0044] In this way, since the gas flows around the recessed portion 144 when it is generated, the temperature of the gas is easily transmitted to the temperature sensor 50 disposed inside the recessed portion 144, and the temperature sensor 50 can more reliably detect the temperature rise caused by the gas. Moreover, since the recessed portion 144 is made of a metal with relatively high thermal conductivity, the temperature rise caused by the gas is quickly transmitted to the temperature sensor 50 via the recessed portion 144.

[0045] Furthermore, since high-temperature gas passes through the inside of the gas pipe 20, i.e., the passage section 142 and the discharge section 143, if the temperature sensor 50 is configured to be directly disposed within the passage section 142, components and structures with sufficient heat resistance to withstand the high-temperature gas are required, raising concerns about increased costs. On the other hand, in this embodiment, since the temperature sensor 50 is disposed on the outside of the gas pipe 20, i.e., the upper surface of the passage section 142, the heat resistance of the temperature sensor 50 and the temperature sensor wiring harness 51 can be reduced, thus suppressing costs.

[0046] Figure 5 This is a flowchart of the thermal interlock detection process performed by controller 3.

[0047] This flowchart is executed in controller 3 at predetermined intervals (e.g., every 10ms). Furthermore, controller 3 is designed for scenarios such as... Figure 1 The multiple battery modules 10 (10a, 10b, 10c, 10d) arranged in the battery pack 2 as shown execute the processes shown in this flowchart in parallel.

[0048] In step S10, the controller 3 receives a signal from the temperature sensor 50 to obtain the temperature at the downstream end of the gas pipeline 20.

[0049] Next, in step S20, the controller 3 determines whether the temperature detected by the temperature sensor 50 has risen above a predetermined temperature within a predetermined time.

[0050] Specifically, the temperature detected by temperature sensor 50 in the previous process is compared with the temperature newly detected by temperature sensor 50 after a predetermined time (e.g., 10 ms) after that temperature detection. If the difference between these temperatures, i.e., the temperature rise, is greater than or equal to a predetermined temperature (e.g., 100 °C), it is determined that the temperature has risen above the predetermined temperature within the predetermined time, and the process proceeds to step S30. If the temperature has not risen above the predetermined temperature within the predetermined time, the process based on this flowchart is temporarily terminated, and the process returns to other steps.

[0051] If step S20 is true, it indicates that the temperature of the gas in the passage section 142 rises sharply in a short period of time. In this case, in step S30, the controller 3 determines that a thermal cascade of the single cell 14 has occurred.

[0052] Figure 6 This is an explanatory diagram showing the temperature change detected by the temperature sensor 50 when a thermal interlock occurs in this embodiment.

[0053] exist Figure 6In the process, during the period from time t0 to time t1, the temperature detected by temperature sensor 50 does not rise above a predetermined temperature within a predetermined time. In this state, the determination in step S20 becomes negative.

[0054] Here, if the temperature rises sharply from time t1 to time t2, and the temperature rise value Th becomes above the predetermined temperature, the controller 3 determines that a thermal cascading has occurred.

[0055] Next, in step S40, controller 3 performs report processing. Report processing may be performed using, for example, warning lights on the driver's dashboard, message reports, alarm-based audible reports, or voice-based alarm reports. This report processing is used to urge the driver to accept service.

[0056] After the processing in step S40, controller 3 returns to other processing.

[0057] Using this Figure 5 The flowchart shown demonstrates the ability to detect thermal cascading events on a per-battery-module-10 basis and to perform appropriate processing (reporting).

[0058] If the controller 3 detects a thermal interlock, it can report an alarm to the driver in the report processing of the aforementioned step S40.

[0059] As described above, the battery pack 2 of this embodiment includes: a housing 11; a battery module 10 housed in the housing 11 and constructed by stacking multiple individual cells 14; and a gas conduit 20 having a passage portion 142 and a discharge portion 143. The passage portion 142 is arranged to cover the upper surface of the battery module 10 and extends along the stacking direction, guiding the gas generated from the individual cells 14 along the stacking direction. The discharge portion 143 is connected to the downstream end of the passage portion 142 and guides the gas to the outside. A temperature sensor 50 is disposed at the downstream end of the passage portion 142 to detect the temperature of the gas flowing to the discharge portion 143.

[0060] In this structure, since a temperature sensor 50 is provided in the gas conduit 20 of the battery module 10, by detecting the temperature rise caused by the gas generated from the individual cell 14 using the temperature sensor 50, thermal chain reaction can be detected earlier than in the conventional case where thermal chain reaction is detected when the internal pressure of the entire battery pack increases. Furthermore, since the temperature sensor 50 is located at the downstream end of the passage 142 of the gas conduit 20, thermal chain reaction can be detected even if gas is generated in any individual cell 14 within the battery module 10.

[0061] In addition, in this embodiment, the temperature sensor 50 is disposed on the upper surface of the passage portion 142 of the gas pipe 20, so it does not come into direct contact with the high-temperature gas. Therefore, the heat resistance temperature of the temperature sensor 50 can be reduced, and the cost can be suppressed while maintaining the temperature detection accuracy.

[0062] In addition, in this embodiment, the passage portion 142 of the gas pipe 20 has a recessed setting portion 144 recessed from the upper surface toward the interior of the passage portion 142 of the gas pipe 20, and the temperature sensor 50 is disposed in the recessed setting portion 144.

[0063] In this structure, the gas flowing through the passage 142 of the gas pipe 20 flows around the recessed setting 144 having a surface 144a orthogonal to the gas flow direction, and the temperature rise caused by the gas can be detected more reliably by the temperature sensor 50.

[0064] In addition, in this embodiment, a voltage sensor is provided to detect the voltage of the single battery 14, and a voltage sensor wiring harness 21 connected to the voltage sensor is arranged along the passage portion 142 of the gas pipe 20 in the stacking direction. A temperature sensor wiring harness 51 connected to the temperature sensor 50 is arranged adjacent to the voltage sensor wiring harness 21.

[0065] In this structure, since the temperature sensor wiring harness 51 of the temperature sensor 50 used to detect the gas temperature is arranged adjacent to the original voltage sensor wiring harness 21 of the battery module 10, there is no need to set up a new structure for the temperature sensor wiring harness 51, thus reducing costs.

[0066] In addition, in this embodiment, the temperature sensor wiring harness 51 and the voltage sensor wiring harness 21 are connected to the same connector 22, and the connector 22 is connected to the controller-side wiring harness 24 that is connected to the controller 3 outside the housing 11.

[0067] In this structure, since the temperature sensor harness 51 used to detect the gas temperature is connected to the existing connector 22 of the battery module 10, there is no need to set up a new connector for the temperature sensor harness 51, thus reducing costs.

[0068] In addition, this embodiment includes a controller 3, which obtains a temperature rise value based on the temperature detected by the temperature sensor 50, and detects the occurrence of thermal chain reaction of the single battery 14 based on the obtained temperature rise value. Therefore, thermal chain reaction of the single battery 14 in the battery module 10 can be detected with a simple structure.

[0069] The above describes the embodiments and variations of the present invention. However, the above embodiments and variations only illustrate a part of the application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0070] In this embodiment, the temperature sensor 50 is disposed in a recessed portion 144 formed by recessing the upper surface of the passage portion 142 of the gas pipe 20. However, it is also possible to omit the recessed portion 144 and instead simply place the temperature sensor 50 on the upper surface of the passage portion 142. Alternatively, the temperature sensor 50 may be configured to be disposed on the side of the passage portion 142.

[0071] In this embodiment, the temperature sensor 50 is located at the downstream end of the passage portion 142, but it is not limited thereto. The temperature sensor 50 may also be located further downstream in the gas flow direction, i.e., at the discharge portion 143. In this case, a recessed portion for arranging the temperature sensor 50 may also be formed in the discharge portion 143.

Claims

1. A battery pack, wherein, This battery pack features: case; The battery module, housed in the housing, is constructed by stacking multiple individual cells; A gas conduit includes a passage section and a discharge section. The passage section is configured to cover the upper surface of the battery module and extends along the stacking direction, guiding the gas generated from the single cell along the stacking direction. The discharge section is connected to the downstream side of the passage section and guides the gas outward. A temperature sensor, disposed at the downstream end of the passage, detects the temperature of the gas flowing toward the discharge section.

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

3. The battery pack according to claim 2, wherein, The passage portion has a recessed portion recessed from the upper surface toward the interior of the passage portion. The temperature sensor is disposed in the recessed area.

4. The battery pack according to claim 1, wherein, The battery pack has a voltage sensor for detecting the voltage of the individual cells. The voltage sensor connected to the voltage sensor is arranged in a wiring harness along the gas pipeline in the stacking direction. The wiring harness for the temperature sensor, which is connected to the temperature sensor, is laid out adjacent to the wiring harness for the voltage sensor.

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

6. A control device for a battery pack, wherein, The battery pack's control device includes: The battery pack according to claim 1; and The controller obtains a temperature rise value based on the temperature detected by the temperature sensor, and detects the occurrence of thermal chain reaction of the single battery based on the obtained temperature rise value.

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