Battery pack for engineering machinery and thermal runaway protection method thereof

Abstract

The invention discloses a battery pack for engineering machinery and a thermal runaway protection method thereof, and belongs to the technical field of thermal runaway of battery packs. The battery pack for the engineering machinery comprises a plurality of battery modules, each battery module comprises a battery cell assembly arranged in the middle and an end plate arranged at the end of the side face of the battery cell assembly, and a pressure sensor is arranged in the middle of the large face of a first battery cell connected with the end plate in the battery cell assembly; the copper bar assembly comprises module copper bars used for connecting the adjacent battery modules and relays used for connecting the adjacent module copper bars, and the relays are used for controlling connection and disconnection between the battery modules; the input end of the thermal runaway early-warning device is connected with the pressure sensor, the output end of the thermal runaway early-warning device is connected with the relay, and the thermal runaway early-warning device is used for judging thermal runaway based on real-time data of the pressure sensor, responding to thermal runaway, outputting a relay disconnection instruction and disconnecting the battery module. The thermal runaway safety performance of the engineering machinery battery system can be improved.

Description

Technical Field

[0001] The present invention relates to a battery pack for engineering machinery and a thermal runaway protection method thereof, belonging to the technical field of thermal runaway of battery packs. Background Art

[0002] With the development of the new energy industry, the application of power batteries has become more and more extensive. In the field of new energy vehicles and engineering machinery, the thermal runaway protection problem of power batteries needs to be solved urgently. The thermal runaway protection strategies and solutions of battery packs mainly include active protection and passive protection. Passive protection is to ensure the safety of power battery products during use by optimizing and blocking the heat spread of thermal runaway cells. Its main solutions include thermal isolation, insulation protection and thermoelectric separation technology; active protection technology based on big data monitoring and prediction is mainly reflected in the use of power battery products. In the design stage of power battery products, the design scheme of passive protection is mainly considered, which is mainly reflected in thermal runaway warning.

[0003] In order to solve the problem of thermal runaway protection of battery packs, the solutions of the existing technology are mainly passive protection solutions to achieve thermoelectric separation. The existing thermal runaway protection strategies and solutions mainly follow the thermal runaway protection strategies and solutions of passenger car battery systems, and have not been customized for the high voltage and multi-module characteristics of battery systems for engineering machinery. For example, the Chinese patent with application number CN202321708268.1 provides a battery pack and a power device, and performs thermoelectric separation after thermal runaway by adjusting the relative position of the battery cell explosion-proof valve and the pole, and increases the exhaust area during thermal runaway through the exhaust channels on both sides. For example, the Chinese patent with application number CN202321675110.9 provides a battery cooling structure and battery pack, which realizes thermoelectric separation by designing the battery cell explosion-proof valve and the pole on the opposite sides, and combines the exhaust channel of the battery cell explosion-proof valve with the cooling mechanism to accelerate the cooling of high-temperature gas. For example, the Chinese patent with application number CN202310761815.0 provides a power battery and a vehicle, which realizes the thermal-electric separation design of the power battery by setting up a diversion area and a high-voltage area in the box. For example, the Chinese patent with application number CN202221488960.3 provides a thermal runaway exhaust guide structure and a vehicle, which guides the flow of high-temperature gas in thermal runaway by setting a closed structure on the battery pack mounting beam, and the exhaust channel after the thermal runaway of the battery cell. For example, the Chinese patent with application number CN202010536236.2 provides a battery module and a battery pack, and a battery cell guide plate is provided on the battery cell. The battery cell guide channel is corresponding to the explosion-proof valve on the battery cell, and the heat generated by the thermal runaway of the battery cell is released to the outside of the battery module through the explosion-proof valve, thereby blocking the diffusion of the high-temperature heat flow ejected from the thermal runaway battery cell on the adjacent battery cells. Regarding the protection problem of thermal runaway of battery packs, there are few active protection solutions in the solutions of the prior art. After thermal runaway of the battery cell occurs, the thermal runaway warning solution usually uses the voltage, temperature, air pressure in the battery pack, smoke alarm and other conditions of the battery cell to comprehensively judge and issue an alarm signal, which has a delayed warning. For example, the Chinese patent with application number CN202010381302.3 provides an early warning method, early warning system and vehicle for thermal runaway of a power battery. The user can learn about the thermal runaway of the power battery through the instrument and / or remote monitoring platform in the early stage of the thermal runaway failure, and then take safety protection measures including leaving the vehicle, which has a delay. After the battery cell inside the battery system has thermal runaway, the battery system does not disconnect the high-voltage connection or send a control command through the BMS to cut off the main relay, and the high-voltage connection between different modules cannot be effectively cut off, and there is a high risk of short circuit. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a battery pack for construction machinery and a thermal runaway protection method thereof, which can improve the thermal runaway safety performance of the construction machinery battery system. To achieve the above purpose, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a battery pack for construction machinery, comprising: A plurality of battery modules, each of which comprises a battery cell assembly arranged in the middle and an end plate arranged at the side end of the battery cell assembly, wherein a pressure sensor is arranged in the middle of the large surface of the first battery cell in the battery cell assembly connected to the end plate; A copper busbar assembly, the copper busbar assembly comprising a module copper busbar for connecting adjacent battery modules and a relay for connecting adjacent module copper busbars, the relay being used to control the on and off between the battery modules; A thermal runaway warning device, wherein the input end of the thermal runaway warning device is connected to the pressure sensor, and the output end is connected to the relay, and is used to make a thermal runaway judgment based on the real-time data of the pressure sensor. In response to the presence of thermal runaway, an instruction to disconnect the relay is output to disconnect the battery module.

[0005] In combination with the first aspect, optionally, aerogel is provided between the pressure sensor and the end plate.

[0006] In combination with the first aspect, optionally, the battery pack for engineering machinery is provided with a tray at the bottom and a box cover at the top; The tray and the box cover are connected in cooperation to form a cavity, and the multiple battery modules and copper busbar assembly are installed in the cavity.

[0007] In combination with the first aspect, optionally, the relay is in a closed state when the battery pack for engineering machinery operates normally.

[0008] In combination with the first aspect, optionally, the thermal runaway warning device is communicatively connected to a battery BMS, and the relay is connected to the battery BMS; The battery BMS is used to verify the thermal runaway judgment based on the real-time data of the pressure sensor. If there is a misjudgment in the thermal runaway judgment, the battery BMS outputs an instruction to close the relay. If there is no misjudgment in the thermal runaway judgment, the battery BMS outputs an instruction to close all relays.

[0009] In a second aspect, the present invention provides a thermal runaway protection method for a battery pack for engineering machinery, which is executed by a thermal runaway warning device, comprising: Get real-time data from pressure sensors; A thermal runaway judgment is performed based on the real-time data of the pressure sensor. In response to the thermal runaway of the battery module, an instruction to disconnect the relay is output to disconnect the battery module.

[0010] In conjunction with the second aspect, optionally, the performing thermal runaway judgment based on real-time data of the pressure sensor includes: Based on the real-time data of the pressure sensor, the real-time pressure and boost rate of the battery module are obtained Determine whether the pressure of the battery module exceeds a preset pressure threshold and whether the boost rate exceeds a preset boost threshold; In response to the pressure of the disconnected battery module exceeding the preset pressure threshold and the pressure increase rate exceeding the preset pressure increase threshold, the duration of exceeding the threshold is calculated, In response to the duration of exceeding the threshold value exceeding a preset duration, the battery module is in thermal runaway.

[0011] In combination with the second aspect, optionally, in response to thermal runaway of the battery module, real-time data of a pressure sensor used for thermal runaway judgment is uploaded to the battery BMS, and the battery BMS verifies the thermal runaway judgment based on the real-time data of the pressure sensor.

[0012] In a third aspect, the present invention provides a thermal runaway protection method for a battery pack for engineering machinery, which is executed by a battery BMS, and includes: Obtain real-time data from pressure sensors used for thermal runaway judgment; Based on the real-time data obtained, the thermal runaway judgment of the thermal runaway warning device is verified; If there is a misjudgment in the thermal runaway judgment, the output relay closes the command; If there is no false judgment in the thermal runaway judgment, an instruction to close all relays is output.

[0013] In combination with the third aspect, optionally, if there is no misjudgment in the thermal runaway judgment, the operating data of the battery pack for engineering machinery is monitored, and if the operating data returns to normal, an instruction to close the relay is output; if the operating data does not return to normal, an alarm is output.

[0014] Compared with the prior art, the battery pack for engineering machinery and the thermal runaway protection method thereof provided in the embodiment of the present invention have the following beneficial effects: The battery module of the present invention comprises a battery cell assembly arranged in the middle and an end plate arranged at the side end of the battery cell assembly, and a pressure sensor is arranged in the middle of the large surface of the first battery cell connected to the end plate in the battery cell assembly; the present invention can warn of a thermal runaway signal in the rapid expansion stage at the early stage of thermal runaway of the battery cell, thereby improving the safety factor of vehicle members; The copper busbar assembly of the present invention comprises a module copper busbar for connecting adjacent battery modules and a relay for connecting adjacent module copper busbars, and the relay is used to control the on-off between the battery modules; the present invention arranges a relay at the output pole position of each battery module, which can cut off the high voltage of the battery module where the relay is located, thereby reducing the risk of heat spread caused by high voltage short circuit after thermal runaway of the battery core assembly; The input end of the thermal runaway warning device of the present invention is connected to a pressure sensor, and the output end is connected to a relay, which is used to make a thermal runaway judgment based on real-time data of the pressure sensor. In response to the existence of thermal runaway, the output relay disconnects an instruction to disconnect the battery module. The present invention can identify the thermal runaway signal through the pressure sensor and quickly cut off the high voltage through the relay. Compared with the conventional method of performing a circuit breaking action after monitoring the battery system data through the BMS system and judging the thermal runaway signal, the present invention can save the circuit breaking time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is an exploded view of a battery pack for engineering machinery provided in Example 1 of the present invention; Figure 2 This is a front view of a copper busbar connection in a battery pack for engineering machinery provided in Example 1 of the present invention; Figure 3 is an exploded view of a battery module in a battery pack for engineering machinery provided in Example 1 of the present invention; Figure 4 is a schematic diagram of a pressure sensor in a battery pack for engineering machinery provided in Example 1 of the present invention; Figure 5 It is a schematic diagram of a thermal runaway protection method for a battery pack for engineering machinery provided in Examples 2 and 3 of the present invention.

[0016] In the figure: 100. Box cover; 200, copper busbar assembly; 201, module copper busbar; 202, relay; 300, battery module; 301, end plate; 302, aerogel; 303, pressure sensor; 304, battery cell assembly; 400. Pallet. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0018] The term "and / or" is only a description of the association relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " generally indicates that the related objects are in an "or" relationship. Embodiment 1:

[0019] like Figure 1 As shown, an embodiment of the present invention provides a battery pack for engineering machinery, including: a plurality of battery modules 300 , a copper busbar assembly 200 , a thermal runaway warning device, a tray 400 and a box cover 100 .

[0020] like Figure 1 As shown, the tray 400 is arranged at the bottom of the battery pack for engineering machinery, and the box cover 100 is arranged at the top. The tray 400 and the box cover 100 are connected to form a cavity, and multiple battery modules 300 and copper busbar assemblies 200 are installed in the cavity.

[0021] The thermal runaway warning device is arranged inside or outside the cavity, preferably outside the cavity.

[0022] like Figure 3 As shown, the battery module 300 includes an end plate 301 , an aerogel 302 , a pressure sensor 303 and a battery cell assembly 304 .

[0023] like Figure 3 As shown, the battery cell assembly 304 is disposed in the middle of the battery module 300 and is composed of a plurality of battery cells arranged in parallel or in series to obtain the battery cell assembly 304 .

[0024] like Figure 3 As shown, the end plate 301 is arranged at the side end of the battery cell assembly 304 , and the pressure sensor 303 is arranged in the middle of the large surface of the first battery cell connected to the end plate 301 in the battery cell assembly 304 .

[0025] like Figure 4 As shown, the pressure sensor 303 adopts a thin-sheet pressure sensor 303. In this embodiment, the pressure sensor 303 is bonded to the large blue film of the battery cell. Before bonding, the probe of the pressure sensor 303 is insulated to avoid puncturing the blue film of the battery cell and causing a short circuit. The aerogel 302 is arranged between the pressure sensor 303 and the end plate 301.

[0026] The threshold setting of the pressure sensor 303 depends on factors such as the battery cell system and grouping method, and must be based on the thermal runaway test data of the actual battery pack.

[0027] It should be noted that the pressure sensor 303 in this embodiment is intended to detect the pressure of the battery cell assembly 304 under collision, which is different from the pack gas pressure sensor 303 provided in the battery BMS.

[0028] Furthermore, other electrical components may be used instead of the pressure sensor 303 to collect the real-time pressure data of the battery cell assembly 304 .

[0029] Aerogel 302 is provided between the pressure sensor 303 and the end plate 301. Aerogel 302 can improve the thermal management performance of the battery cells at the end of the battery cell assembly 304, and can also effectively avoid the risk of insulation failure.

[0030] This embodiment can use the pressure sensor 303 to warn of the occurrence of thermal runaway in the rapid expansion stage before the thermal runaway of the battery cell, thereby improving the safety factor of the vehicle occupants.

[0031] like Figure 2 As shown, the copper busbar assembly 200 includes a module copper busbar 201 and a relay 202. The module copper busbar 201 is used to connect adjacent battery modules 300, and the relay 202 is used to connect adjacent module copper busbars 201 to control the on-off between the battery modules 300. The relay 202 is in a closed state when the battery pack for engineering machinery works normally.

[0032] Furthermore, other electrical components may be used instead of the relay 202 to control the on / off of the battery modules 300 .

[0033] After the copper busbar assembly 200 is connected to the battery module 300, there is a relay 202 at the output pole of each battery module 300, which can cut off the high voltage of the battery module 300 where the relay 202 is located, reducing the risk of heat spread caused by high voltage short circuit after thermal runaway of the battery cell assembly 304.

[0034] The input end of the thermal runaway warning device is connected to the pressure sensor 303, and the output end is connected to the relay 202. The thermal runaway warning device is used to make a thermal runaway judgment based on the real-time data of the pressure sensor 303, and in response to the presence of thermal runaway, outputs an instruction to disconnect the relay 202, disconnecting the battery module 300.

[0035] Specifically, the thermal runaway warning device executes a thermal runaway protection method for a battery pack for engineering machinery provided in Example 2.

[0036] The thermal runaway warning device is connected to the battery BMS in communication, and the relay 202 is connected to the battery BMS. The battery BMS is used to verify the thermal runaway judgment based on the real-time data of the pressure sensor 303. If there is a misjudgment of the thermal runaway judgment, the battery BMS outputs a command to close the relay 202. If there is no misjudgment of the thermal runaway judgment, the battery BMS outputs a command to close all the relays 202.

[0037] Specifically, the battery BMS executes a thermal runaway protection method for a battery pack for engineering machinery provided in Example 3.

[0038] In this embodiment, the thermal runaway signal is identified by the pressure sensor 303, and the high voltage is quickly cut off by the relay 202. Compared with the conventional method of monitoring the battery system data through the BMS system and then determining the thermal runaway signal and then executing the circuit breaking action, the battery pack for engineering machinery provided in this embodiment can save the circuit breaking time and improve the safety factor of the vehicle members. Embodiment 2:

[0039] The embodiment of the present invention provides a thermal runaway protection method for a battery pack for engineering machinery based on the battery pack for engineering machinery provided in embodiment 1, which is executed by a thermal runaway warning device, such as Figure 5 As shown, including: Acquire real-time data from the pressure sensor 303; A thermal runaway judgment is performed based on the real-time data of the pressure sensor 303 , and in response to the thermal runaway of the battery module 300 , an instruction to disconnect the output relay 202 is output to disconnect the battery module 300 .

[0040] The thermal runaway judgment is performed based on the real-time data of the pressure sensor 303, and the specific steps include: Step 1: Based on the real-time data of the pressure sensor 303 , obtain the real-time pressure and pressure increase rate of the battery module 300 .

[0041] Step 2: Determine whether the pressure of the battery module 300 exceeds a preset pressure threshold and whether the pressure increase rate exceeds a preset pressure increase threshold.

[0042] The preset pressure threshold and the preset boost threshold depend on factors such as the battery cell system and grouping method, and must be based on the thermal runaway test data of the actual battery pack.

[0043] When the pressure of the battery module 300 does not exceed the preset pressure threshold and / or the boost rate does not exceed the preset boost threshold, the thermal runaway judgment is exited, and the pressure and boost rate of the battery module 300 are continuously acquired and monitored.

[0044] Step 3: In response to the pressure of the battery module 300 exceeding the preset pressure threshold and the pressure increase rate exceeding the preset pressure increase threshold, calculate the duration of exceeding the threshold.

[0045] When the duration of the pressure of the battery module 300 exceeding the preset pressure threshold is inconsistent with the duration of the boost rate exceeding the preset boost threshold, the larger value is output as the duration of exceeding the threshold.

[0046] Step 4: In response to the duration of exceeding the threshold value exceeding a preset duration, the battery module 300 is in thermal runaway.

[0047] When the duration of exceeding the threshold does not exceed the preset duration, continue to monitor the pressure and boost rate of the battery module 300 until the pressure of the battery module does not exceed the preset pressure threshold and / or the boost rate does not exceed the preset boost threshold, and exit the thermal runaway judgment.

[0048] like Figure 5 As shown, in response to the thermal runaway of the battery module 300 , the real-time data of the pressure sensor 303 used for thermal runaway judgment is uploaded to the battery BMS, and the battery BMS verifies the thermal runaway judgment based on the real-time data of the pressure sensor 303 .

[0049] In this embodiment, the thermal runaway warning device executes the thermal runaway protection method for the battery pack for engineering machinery, identifies the thermal runaway signal through the pressure sensor 303, and quickly cuts off the high voltage through the relay 202, which can save the circuit breaking time and improve the safety factor of the vehicle members. Embodiment 3:

[0050] The embodiment of the present invention provides a thermal runaway protection method for a battery pack for engineering machinery based on a battery pack for engineering machinery provided in Example 1 or a thermal runaway protection method for a battery pack for engineering machinery provided in Example 2, which is executed by a battery BMS, such as Figure 5 As shown, including: Acquiring real-time data of the pressure sensor 303 for thermal runaway judgment; Based on the real-time data obtained, the thermal runaway judgment of the thermal runaway warning device is verified; If there is a misjudgment in the thermal runaway judgment, an instruction to close the output relay 202 is output; If there is no misjudgment in the thermal runaway judgment, an instruction to close all relays 202 is output.

[0051] Furthermore, if there is no misjudgment in the thermal runaway judgment, the operating data of the battery pack for engineering machinery is monitored. If the operating data returns to normal, an instruction to close the relay 202 is output; if the operating data does not return to normal, an alarm is output.

[0052] Specifically, the alarm is displayed through a human-computer interaction interface.

[0053] like Figure 5As shown, the operating data of the battery pack for engineering machinery monitored by the battery BMS in this embodiment includes battery cell temperature, battery cell voltage, pack gas pressure, and battery pack internal temperature.

[0054] In this embodiment, the thermal runaway judgment is verified by the battery BMS to correct the high voltage disconnection of the battery system caused by the misjudgment of thermal runaway due to unexpected circumstances.

[0055] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A battery pack for construction machinery, characterized in that: include: A plurality of battery modules, each of which comprises a battery cell assembly arranged in the middle and an end plate arranged at the side end of the battery cell assembly, wherein a pressure sensor is arranged in the middle of the large surface of the first battery cell in the battery cell assembly connected to the end plate; A copper busbar assembly, the copper busbar assembly comprising a module copper busbar for connecting adjacent battery modules and a relay for connecting adjacent module copper busbars, the relay being used to control the on and off between the battery modules; A thermal runaway warning device, wherein the input end of the thermal runaway warning device is connected to the pressure sensor, and the output end is connected to the relay, and is used to make a thermal runaway judgment based on the real-time data of the pressure sensor. In response to the presence of thermal runaway, an instruction to disconnect the relay is output to disconnect the battery module.

2. The battery pack for construction machinery according to claim 1, characterized in that: Aerogel is arranged between the pressure sensor and the end plate.

3. The battery pack for construction machinery according to claim 1, characterized in that: The battery pack for engineering machinery has a tray at the bottom and a box cover at the top; The tray and the box cover are connected in cooperation to form a cavity, and the multiple battery modules and copper busbar assembly are installed in the cavity.

4. The battery pack for construction machinery according to claim 1, characterized in that: The relay is in a closed state when the battery pack for engineering machinery operates normally.

5. The battery pack for construction machinery according to claim 1, characterized in that: The thermal runaway warning device is communicatively connected to the battery BMS, and the relay is connected to the battery BMS; The battery BMS is used to verify the thermal runaway judgment based on the real-time data of the pressure sensor. If there is a misjudgment in the thermal runaway judgment, the battery BMS outputs an instruction to close the relay. If there is no misjudgment in the thermal runaway judgment, the battery BMS outputs an instruction to close all relays.

6. A thermal runaway protection method for a battery pack for engineering machinery, characterized in that: Executed by the thermal runaway warning device, including: Get real-time data from pressure sensors; A thermal runaway judgment is performed based on the real-time data of the pressure sensor. In response to the thermal runaway of the battery module, an instruction to disconnect the relay is output to disconnect the battery module.

7. The thermal runaway protection method for a battery pack for engineering machinery according to claim 6, characterized in that: The thermal runaway judgment based on the real-time data of the pressure sensor includes: Based on the real-time data of the pressure sensor, the real-time pressure and boost rate of the battery module are obtained Determine whether the pressure of the battery module exceeds a preset pressure threshold and whether the boost rate exceeds a preset boost threshold; In response to the pressure of the disconnected battery module exceeding the preset pressure threshold and the pressure increase rate exceeding the preset pressure increase threshold, the duration of exceeding the threshold is calculated, In response to the duration of exceeding the threshold value exceeding a preset duration, the battery module is in thermal runaway.

8. The thermal runaway protection method for a battery pack for engineering machinery according to claim 6, characterized in that: In response to the presence of thermal runaway in the battery module, real-time data of a pressure sensor used for thermal runaway judgment is uploaded to the battery BMS, and the battery BMS verifies the thermal runaway judgment based on the real-time data of the pressure sensor.

9. A thermal runaway protection method for a battery pack for engineering machinery, characterized in that: Executed by the battery BMS, including: Obtain real-time data from pressure sensors used for thermal runaway judgment; Based on the real-time data obtained, the thermal runaway judgment of the thermal runaway warning device is verified; If there is a misjudgment in the thermal runaway judgment, the output relay closes the command; If there is no false judgment in the thermal runaway judgment, an instruction to close all relays is output.

10. The thermal runaway protection method for a battery pack for engineering machinery according to claim 9, characterized in that: If there is no misjudgment in the thermal runaway judgment, the operating data of the battery pack for construction machinery is monitored. If the operating data returns to normal, an instruction to close the relay is output; if the operating data does not return to normal, an alarm is output.

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