A verification method for battery pack thermal runaway alarm control strategy

Abstract

A verification method for a battery pack thermal runaway alarm control strategy of the present invention belongs to the technical field of battery pack thermal runaway, and includes S100, manufacturing a thermal runaway module; S200, normally installing the manufactured thermal runaway module in the battery pack; S300, building a test bench, and heating the thermal runaway module by testing a heating system; S400, verifying the thermal runaway judgment of a BMS according to the alarm control strategy, by setting a target cell in the battery pack, and monitoring and processing the target cell to simulate some scenarios of thermal runaway, and judging whether the thermal runaway control strategy of the battery pack is accurate and appropriate according to the detection results of the BMS and its processing behavior.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal runaway of battery packs, and specifically is a verification method for a thermal runaway alarm control strategy of a battery pack. Background Art

[0002] In recent years, with the increasing global environmental protection and energy issues, the development of international electrification industrialization has accelerated, and lithium-ion batteries have been widely used in people's lives and production today, such as electric vehicles, home energy storage, outdoor mobile power supplies, etc. At the same time, with the increase in demand for lithium-ion battery applications, the requirements for its energy density are also getting higher and higher, and the accompanying battery safety risks are also gradually increasing, and battery thermal runaway is the main factor affecting battery safety.

[0003] As the whole vehicle has higher and higher requirements for battery pack safety, the requirements of never catching fire and never spreading are put forward. The existing test technology scheme is to use a heating plate clamped between two triggering cells, with the target cell directly in contact with the heating plate, and the other large surface of the cell needs to be insulated with a heat shield to prevent the two cells from igniting during the test and causing the test to fail. Due to the use of the heat shield, this scheme is inconsistent with the actual state of thermal runaway events. Therefore, how to effectively warn and protect against thermal runaway without changing the installation of the cell in the battery pack has become a problem that needs to be solved urgently. Summary of the invention

[0004] 1. Technical problem to be solved by the invention

[0005] The purpose of the present invention is to solve the problem that the existing heat collector is heated unevenly under sunlight.

[0006] 2. Technical solution

[0007] In order to achieve the above object, the technical solution provided by the present invention is:

[0008] A verification method for a battery pack thermal runaway alarm control strategy of the present invention includes the following contents:

[0009] S100, making thermal runaway module;

[0010] S200, install the manufactured thermal runaway module in the battery pack normally;

[0011] S300, build a test bench and heat the thermal runaway module through the test heating system;

[0012] S400: verifying the thermal runaway determination of the BMS according to the alarm control strategy.

[0013] Preferably, the thermal runaway module in step S100 includes a target module, a thermal runaway target cell and a thermocouple, the thermal runaway target cell has a built-in heating film, the thermal runaway target cell is located at the third position of the negative end of the target module, the target module contains four NTCs, namely NTC1, NTC2, NTC3 and NTC4, and the four NTCs all have a cell management system to collect temperature.

[0014] Preferably, the target module comprises a plurality of common battery cells arranged in sequence, and thermocouples are provided between the first common battery cell to the fifth common battery cell starting from the negative end of the target module, and are correspondingly numbered T1 to T5.

[0015] Preferably, thermocouples are arranged on both sides of the thermal runaway target cell and are numbered T6 and T7 accordingly.

[0016] Preferably, the alarm control strategy in step S400 includes the following contents:

[0017] Sa, pressure increase: the pressure increase CAN signal status is set;

[0018] Sb, pressure increase rate: pressure increase CAN signal status set;

[0019] Sc, voltage drop: the voltage drop of any common battery cell exceeds 25% within 3S;

[0020] Sd, voltage is too low: the voltage of a single ordinary battery cell is less than U1V, and the duration is ≥2S;

[0021] Se, CMC communication disconnection: CMC communication disconnection, duration ≥ 2S;

[0022] Sf, temperature is too high: maximum temperature Tmax>75℃, lasting for 2S;

[0023] Sg, the temperature rise rate is too large: the temperature rise is too fast dT / dt>3℃ / s, and the temperature of the temperature rise point - the average temperature>15℃.

[0024] Sh, the temperature difference is too large: Tmax-Tmin>30℃, and the maximum temperature-average temperature>15℃;

[0025] Si, pressure sensor failure: the pressure sensor signal stops updating;

[0026] Sj, Rolling Counter abnormality;

[0027] Sk, Pressure monitor communication timeout.

[0028] Preferably, the judgment time of 1800ms for the temperature difference is cancelled in Sg: for the first temperature rise point t1 that needs to meet the condition, t1 is compared with the average temperature excluding t1 to determine whether the temperature difference condition is met. If so, the Sh condition is latched for 600S; if not, the second temperature rise point t2 is locked. After t2 is locked, t2 is compared with the average temperature excluding t1 and t2 to determine whether the temperature difference condition is met. If so, the Sh condition is latched again for 600S, and the judgment and refresh are repeated in a downward cycle.

[0029] Preferably, in step S400, the BMS receives a wake-up signal and starts a power-on self-test. When the BMS is successfully powered on and initialized, it enters a thermal runaway fault detection and judgment process, wherein the thermal runaway judgment conditions include but are not limited to the following 10 conditions, and if any of the following 10 conditions occurs, the battery pack is judged to have a thermal runaway fault. The 10 conditions are as follows:

[0030] P1, when Se, Sg, and Sa occur simultaneously;

[0031] P2, when Se, Sh, and Sa occur simultaneously;

[0032] P3, when Se, Si, and Sa occur simultaneously;

[0033] P4, when Sc, Sh, and Sa occur simultaneously;

[0034] P5, when Se, Sg, and Sb occur simultaneously;

[0035] P6, when Se, Sh, and Sb occur simultaneously;

[0036] P7, when Se, Si, and Sb occur simultaneously;

[0037] P8, when Sc, Sh, and Sb occur simultaneously;

[0038] P9, when Sj, Sk and Si occur, the pressure increase of Sa in P1, P2, P3 and P4 is judged as valid by default;

[0039] P10, when Sj, Sk and Si occur, the Sb pressure in P5, P6, P7 and P8 increases too fast and is judged as valid by default.

[0040] Preferably, the battery pack thermal runaway fault detection also includes the following conditions:

[0041] Q1, the signal needs to be filtered, the fault is maintained for 1S, HVM29_ThermalDiffusion is reported, and the DTC code P1BB000 is recorded;

[0042] Q2, execute high voltage power-off: first disconnect the main positive relay, and then disconnect the main negative relay after a delay of 500ms;

[0043] Q3, thermal runaway fault needs to be latched and cleared by UDS;

[0044] Q4, the thermal runaway fault detection and judgment process continues to cycle detection after the BMS is powered on;

[0045] Q5, when the thermal runaway conditions are not met, the BMS is continuously awakened by the BPS hardwire for more than 2 hours and the relevant DTC is reported.

[0046] Preferably, the alarm control strategies Sa~Sk all need to satisfy the fault recovery clearing hysteresis time of not less than 600S.

[0047] 3. Beneficial effects

[0048] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0049] A verification method for a battery pack thermal runaway alarm control strategy of the present invention sets a target cell in the battery pack and monitors and processes the target cell to simulate some scenarios where thermal runaway occurs, and determines whether the battery pack thermal runaway control strategy is accurate and appropriate based on the detection results of the BMS and its processing behavior. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 NTC position intention of a verification method of a battery pack thermal runaway alarm control strategy of the present invention;

[0051] Figure 2 A schematic diagram of the thermocouple positions of a verification method for a battery pack thermal runaway alarm control strategy of the present invention;

[0052] Figure 3 A thermocouple temperature variation curve diagram of a verification method for a battery pack thermal runaway alarm control strategy of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0055] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0056] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0057] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] Example 1

[0060] See attached Figure 1-3 , a verification method of a battery pack thermal runaway alarm control strategy of this embodiment includes the following contents:

[0061] S100, making thermal runaway module;

[0062] S200, install the manufactured thermal runaway module in the battery pack normally;

[0063] S300, build a test bench and heat the thermal runaway module through the test heating system;

[0064] S400: verifying the thermal runaway determination of the BMS according to the alarm control strategy.

[0065] The thermal runaway module in step S100 of the present embodiment includes a target module, a thermal runaway target cell and a thermocouple. The thermal runaway target cell has a built-in heating film. The thermal runaway target cell is located at the third position of the negative terminal of the target module. The target module contains four NTCs, namely NTC1, NTC2, NTC3 and NTC4. All four NTCs have a cell management system to collect temperature.

[0066] The target module of the present embodiment comprises a plurality of common battery cells arranged in sequence, and thermocouples are provided between the first common battery cell to the fifth common battery cell starting from the negative end of the target module, and are numbered T1 to T5 accordingly.

[0067] Thermocouples are arranged on both sides of the thermal runaway target cell of this embodiment and are numbered T6 and T7 accordingly.

[0068] The alarm control strategy in step S400 of this embodiment includes the following contents:

[0069] Sa, pressure increase: the pressure increase CAN signal status is set;

[0070] Sb, pressure increase rate: pressure increase CAN signal status set;

[0071] Sc, voltage drop: the voltage drop of any common battery cell exceeds 25% within 3S;

[0072] Sd, voltage is too low: the voltage of a single ordinary battery cell is less than U1V, and the duration is ≥2S;

[0073] Se, CMC communication disconnection: CMC communication disconnection, duration ≥ 2S;

[0074] Sf, temperature is too high: maximum temperature Tmax>75℃, lasting for 2S;

[0075] Sg, the temperature rise rate is too large: the temperature rise is too fast dT / dt>3℃ / s, and the temperature of the temperature rise point - the average temperature>15℃.

[0076] Sh, the temperature difference is too large: Tmax-Tmin>30℃, and the maximum temperature-average temperature>15℃;

[0077] Si, pressure sensor failure: the pressure sensor signal stops updating;

[0078] Sj, Rolling Counter abnormality;

[0079] Sk, Pressure monitor communication timeout.

[0080] In Sg of this embodiment, the judgment time of 1800ms for the temperature difference is cancelled: for the first temperature rise point t1 that needs to meet the condition, t1 is compared with the average temperature excluding t1 to determine whether the temperature difference condition is met. If so, the Sh condition is latched for 600S; if not, the second temperature rise point t2 is locked. After t2 is locked, t2 is compared with the average temperature excluding t1 and t2 to determine whether the temperature difference condition is met. If so, the Sh condition is latched again for 600S, and the judgment and refresh are repeated in a cycle.

[0081] In step S400 of this embodiment, the BMS receives the wake-up signal and starts power-on self-test. When the BMS is successfully powered on and self-tested and initialized, it enters the thermal runaway fault detection and judgment process, where the thermal runaway judgment conditions include but are not limited to the following 10 conditions, and if any of the following 10 conditions occurs, the battery pack is judged to have a thermal runaway fault. The 10 conditions are as follows:

[0082] P1, when Se, Sg, and Sa occur simultaneously;

[0083] P2, when Se, Sh, and Sa occur simultaneously;

[0084] P3, when Se, Si, and Sa occur simultaneously;

[0085] P4, when Sc, Sh, and Sa occur simultaneously;

[0086] P5, when Se, Sg, and Sb occur simultaneously;

[0087] P6, when Se, Sh, and Sb occur simultaneously;

[0088] P7, when Se, Si, and Sb occur simultaneously;

[0089] P8, when Sc, Sh, and Sb occur simultaneously;

[0090] P9, when Sj, Sk and Si occur, the pressure increase of Sa in P1, P2, P3 and P4 is judged as valid by default;

[0091] P10, when Sj, Sk and Si occur, the Sb pressure in P5, P6, P7 and P8 increases too fast and is judged as valid by default.

[0092] The battery pack thermal runaway fault detection in this embodiment also includes the following conditions:

[0093] Q1, the signal needs to be filtered, the fault is maintained for 1S, HVM29_ThermalDiffusion is reported, and the DTC code P1BB000 is recorded;

[0094] Q2, execute high voltage power-off: first disconnect the main positive relay, and then disconnect the main negative relay after a delay of 500ms;

[0095] Q3, thermal runaway fault needs to be latched and cleared by UDS;

[0096] Q4, the thermal runaway fault detection and judgment process continues to cycle detection after the BMS is powered on;

[0097] Q5, when the thermal runaway conditions are not met, the BMS is continuously awakened by the BPS hardwire for more than 2 hours and the relevant DTC is reported.

[0098] The alarm control strategies Sa~Sk of this embodiment all need to satisfy that the fault recovery clearing hysteresis time is not less than 600S.

[0099] The above embodiments only express a certain implementation mode of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A verification method for a battery pack thermal runaway alarm control strategy, characterized in that: It includes the following: S100, making thermal runaway module; S200, install the manufactured thermal runaway module in the battery pack normally; S300, build a test bench and heat the thermal runaway module through the test heating system; S400, verifying the thermal runaway determination of the BMS according to the alarm control strategy; The alarm control strategy in step S400 includes the following contents: Sa, pressure increase: the pressure increase CAN signal status is set; Sb, pressure increase rate: pressure increase rate CAN signal status setting; Sc, voltage drop: the voltage drop of any common battery cell exceeds 25% within 3S; Sd, voltage is too low: the voltage of a single ordinary battery cell is less than U1V, and the duration is ≥2S; Se, CMC communication disconnection: CMC communication disconnection, duration ≥ 2S; Sf, temperature is too high: maximum temperature Tmax>75℃, lasting for 2S; Sg, the temperature rise rate is too large: the temperature rise is too fast dT / dt>3℃ / s, and the temperature of the temperature rise point - the average temperature>15℃. Sh, the temperature difference is too large: Tmax-Tmin>30℃, and the maximum temperature-average temperature>15℃; Si, pressure sensor failure: the pressure sensor signal stops updating; Sj, Rolling Counter abnormality; Sk, pressure monitor communication timeout; The judgment time of canceling the temperature difference of 1800ms in Sg: the first temperature rise point t1 that needs to meet the condition is compared with the average temperature excluding t1 to determine whether the temperature difference condition is met. If it is met, the Sh condition is latched for 600S; If the condition is not met, the second temperature rise point t2 is locked. After locking t2, t2 is compared with the average temperature excluding t1 and t2 to determine whether the temperature difference condition is met. If it is met, the Sh condition is re-latched for 600S, and the judgment is refreshed in a cycle.

2. The method for verifying a battery pack thermal runaway alarm control strategy according to claim 1, characterized in that: The thermal runaway module in step S100 includes a target module, a thermal runaway target cell and a thermocouple. The thermal runaway target cell has a built-in heating film. The thermal runaway target cell is located at the third position of the negative end of the target module. The target module contains four NTCs, namely NTC1, NTC2, NTC3 and NTC4. The four NTCs all have a cell management system to collect temperature.

3. The verification method of a battery pack thermal runaway alarm control strategy according to claim 2, characterized in that: The target module comprises a plurality of common battery cells arranged in sequence, and thermocouples are arranged between the first common battery cell to the fifth common battery cell starting from the negative end of the target module, and are numbered T1 to T5 accordingly.

4. The method for verifying a battery pack thermal runaway alarm control strategy according to claim 3, characterized in that: Thermocouples are arranged on both sides of the thermal runaway target cell and are numbered T6 and T7 accordingly.

5. The verification method of a battery pack thermal runaway alarm control strategy according to claim 1, characterized in that: In step S400, the BMS receives the wake-up signal and starts power-on self-test. When the BMS is successfully powered on and self-tested and initialized, it enters the thermal runaway fault detection and judgment process, where the thermal runaway judgment conditions include but are not limited to the following 10 conditions, and if any of the following 10 conditions occurs, the battery pack is judged to have a thermal runaway fault. The 10 conditions are as follows: P1, when Se, Sg, and Sa occur simultaneously; P2, when Se, Sh, and Sa occur simultaneously; P3, when Se, Si, and Sa occur simultaneously; P4, when Sc, Sh, and Sa occur simultaneously; P5, when Se, Sg, and Sb occur simultaneously; P6, when Se, Sh, and Sb occur simultaneously; P7, when Se, Si, and Sb occur simultaneously; P8, when Sc, Sh, and Sb occur simultaneously; P9, when Sj, Sk and Si occur, the pressure increase of Sa in P1, P2, P3 and P4 is judged as valid by default; P10, when Sj, Sk and Si occur, the Sb pressure in P5, P6, P7 and P8 increases too fast and is judged as valid by default.

6. A method for verifying a battery pack thermal runaway alarm control strategy according to claim 5, characterized in that: Battery pack thermal runaway fault detection also includes the following conditions: Q1, the signal needs to be filtered, the fault lasts for 1S and is reported HVM29_ThermalDiffusion, record DTC code P1BB000; Q2, execute high voltage power-off: first disconnect the main positive relay, and then disconnect the main negative relay after a delay of 500ms; Q3, thermal runaway fault needs to be latched and cleared by UDS; Q4, the thermal runaway fault detection and judgment process continues to cycle detection after the BMS is powered on; Q5, when the thermal runaway conditions are not met, the BMS is continuously awakened by the BPS hardwire for more than 2 hours and the relevant DTC is reported.

7. The method for verifying a battery pack thermal runaway alarm control strategy according to claim 1, characterized in that: The alarm control strategies Sa~Sk all need to meet the requirement that the fault recovery and clearing hysteresis time is not less than 600S.

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