Intelligent protection system for lithium battery pack based on multi-stage temperature monitoring

Abstract

The utility model discloses a kind of lithium battery group intelligent protection systems based on multistage temperature monitoring belongs to lithium battery protection technical field, including main control chip level first temperature protection unit and hardware level second temperature protection unit;The first temperature protection unit includes the multiplex NTC connected with main control chip;The second temperature protection unit includes multiple mechanical temperature switches TS directly connected between charging MOSFET and main control chip 1~n。 Through the above manner, the utility model realizes the full domain temperature coverage of multiple string battery group, fast response (<50ms) and high reliability (failure probability <1*E ‑9 ) by the double protection framework of main control chip level NTC monitoring and hardware level mechanical temperature switch. It is especially suitable for lithium battery thermal safety management under high power density scene.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery protection technology, specifically to an intelligent protection system for lithium battery packs based on multi-level temperature monitoring. Background Technology

[0002] Existing lithium battery protection solutions have the following limitations:

[0003] 1. Insufficient single-point monitoring: Traditional solutions rely on single-chip integrated temperature detection (such as TI BQ76940), which only supports 2 NTC inputs and is difficult to cover the full-range temperature monitoring of multiple battery packs (such as 24 or more), resulting in monitoring blind spots.

[0004] 2. Insufficient accuracy and response speed: Existing solutions (such as protection logic based on pure software) cannot achieve precise temperature protection at the unit level, and the delay of software shutdown of MOS is relatively high (>500ms), which poses a risk of thermal runaway.

[0005] 3. Lack of redundancy design: The charging circuit protection relies on a single electronic switch (such as a MOSFET), lacking a hardware-level direct disconnection redundancy mechanism, resulting in a high probability of system failure (>1*E). -6 ).

[0006] Based on this, this utility model designs an intelligent protection system for lithium battery packs based on multi-level temperature monitoring to solve the above problems. Utility Model Content

[0007] In view of the above-mentioned shortcomings of the existing technology, this utility model provides a lithium battery pack intelligent protection system based on multi-level temperature monitoring.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] A lithium battery pack intelligent protection system based on multi-level temperature monitoring includes a primary temperature protection unit at the main control chip level and a secondary temperature protection unit at the hardware level. The primary temperature protection unit includes multiple NTCs connected to the main control chip. The secondary temperature protection unit includes multiple mechanical temperature switches TS directly connected in series between the charging MOSFET and the main control chip. 1~n。

[0010] Furthermore, three high-precision NTCs (NTC1, NTC2, and NTC3) are used to connect to the main control chip; NTC1 and NTC2 are arranged at the center of the geometric surface of the battery pack, while NTC3 is arranged close to the heat dissipation area of ​​the power device.

[0011] Furthermore, the main control chip is the SH3676016 main control chip.

[0012] Furthermore, the three high-precision NTC signals are input to the SH3676016 main control chip after RC filtering and decoupling capacitors, with a sampling frequency of 1kHz.

[0013] Furthermore, the capacitance value of the decoupling capacitor is 0.1μF.

[0014] Furthermore, the mechanical temperature switch TS 1~n Select the TS-223 temperature switch; the default state is normally closed.

[0015] Furthermore, mechanical temperature switches TS 1~n It is mounted on the surface of the battery pack, and its mounting position covers the geometric center of the battery pack and the heat dissipation area of ​​the power devices.

[0016] Furthermore, the main control chip is connected to the MCU and the emergency protection mechanism; the secondary temperature protection unit is connected to the status indication unit A and the protection execution unit A, and the primary temperature protection unit is connected to the protection execution unit B and the status indication unit B; the status indication unit A, the protection execution unit A, the protection execution unit B, and the status indication unit are all connected to the main control chip.

[0017] Furthermore, both status indicator unit A and status indicator unit B are status indicator lights; the protection execution unit A consists of several sets of fans, the installation positions of which correspond to the positions of the mechanical temperature switches; the protection execution unit B consists of several sets of cooling chips, the installation positions of which correspond to the installation positions of the NTC.

[0018] Furthermore, the emergency protection mechanism includes fire detection devices and fire extinguishing equipment.

[0019] Compared with the prior art, the advantages of this utility model are as follows: 1. High monitoring coverage: Three-channel NTC + 24-channel mechanical temperature switch TS achieve full coverage, and the number of monitoring nodes is increased by 300% (taking a 24-cell battery pack as an example).

[0020] 2. Fast response speed: Hardware protection response time <50ms;

[0021] 3. High reliability: Employing a dual-path independent protection mechanism with a primary temperature protection unit at the main control chip level and a secondary temperature protection unit at the hardware level, the system failure probability can be reduced to 1*E. -9 . Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the connection structure between the primary temperature protection unit and the main control chip of this utility model.

[0024] Figure 2 This is a schematic diagram of the connection structure between the secondary temperature protection unit and the main control chip of this utility model.

[0025] Figure 3 This is a structural diagram of a lithium battery pack intelligent protection system based on multi-level temperature monitoring according to this utility model. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0027] Example 1: In some embodiments, please refer to the accompanying drawings. Figures 1-2 A lithium battery pack intelligent protection system based on multi-level temperature monitoring includes a primary temperature protection unit at the main control chip level and a secondary temperature protection unit at the hardware level.

[0028] The primary temperature protection unit includes multiple high-precision NTC (Negative Temperature Coefficient) thermistors (±1℃) connected to the main control chip.

[0029] Preferably, three high-precision NTCs, NTC1, NTC2, and NTC3, are connected to the main control chip; NTC1 and NTC2 are arranged at the center of the geometric surface of the battery pack, and NTC3 is arranged close to the heat dissipation area of ​​the power device (e.g., MOSFET (metal-oxide-semiconductor field-effect transistor)) to monitor the temperature distribution of the entire area in real time.

[0030] Preferably, the main control chip is an SH3676016 main control chip;

[0031] Furthermore, the three high-precision NTC signals are input to the SH3676016 main control chip after RC filtering and decoupling capacitors, with a sampling frequency of 1kHz.

[0032] Furthermore, the capacitance value of the decoupling capacitor is 0.1μF.

[0033] The main control chip compares the temperature value monitored by the NTC with the preset temperature threshold. If any NTC exceeds the preset temperature threshold, the main control chip immediately forces the CHG_EN level to go low and cuts off the charging MOSFET (response time <50ms).

[0034] The secondary temperature protection unit includes multiple mechanical temperature switches TS connected in series between the charging MOSFET and the main control chip. 1~n (For example, n=24), the mechanical temperature switch TS 1~n The switching action value is 50±5℃, directly responding to individual unit over-temperature without the need for main control intervention;

[0035] Preferably, the mechanical temperature switch TS 1~n Select the TS-223 temperature switch; the default state is normally closed.

[0036] Preferably, a mechanical temperature switch TS 1~n It is mounted on the surface of the battery pack, and its mounting position covers the geometric center of the battery pack and the heat dissipation area of ​​the power devices.

[0037] Furthermore, a TS-223 temperature switch is attached to the positive terminal of the battery pack, and it is in close contact with the battery surface through thermally conductive adhesive to ensure heat conduction efficiency.

[0038] This invention connects all mechanical temperature switches TS1~n in series via the CHG_EN signal of the main control chip to drive the charging MOSFET (e.g., NEC039N10). When any mechanical temperature switch is triggered, the main control chip immediately forces the CHG_EN level low to cut off the charging MOSFET (response time <50ms).

[0039] If either the primary temperature protection unit or the hardware-level secondary temperature protection unit is triggered, the main control chip will immediately cut off the charging MOSFET to reduce the risk.

[0040] This invention achieves full-range temperature coverage, rapid response (<50ms), and high reliability (failure probability <1*E) for multi-cell battery packs through a dual protection architecture of main control chip-level NTC monitoring and hardware-level mechanical temperature switch. -9 It is particularly suitable for lithium battery thermal safety management in high power density scenarios.

[0041] Example 2: Based on Example 1, please refer to the accompanying drawings in the specification. Figure 3 The main control chip is connected to the MCU and the emergency protection mechanism; the secondary temperature protection unit is connected to the status indication unit A and the protection execution unit A; the primary temperature protection unit is connected to the protection execution unit B and the status indication unit B; the status indication unit A, the protection execution unit A, the protection execution unit B, and the status indication unit are all connected to the main control chip.

[0042] The status indicator unit A is a status indicator light. The status indicator light is off by default. When the mechanical temperature switch of the secondary temperature protection unit is triggered, the status indicator light corresponding to the mechanical temperature switch lights up, thereby determining which mechanical temperature switch was triggered. Managers can intuitively understand the triggering status of the lithium battery pack and can also count the number of times each mechanical temperature switch is triggered. For positions that are frequently triggered (exceeding the preset number of times), timely maintenance can be carried out to reduce abnormal situations.

[0043] The status indicator unit B is a status indicator light. The status indicator light is off by default. When an NTC in the first-level temperature protection unit exceeds the preset temperature threshold, the status indicator light corresponding to the NTC will light up, thereby determining which NTC in which position exceeds the preset temperature threshold. Managers can intuitively know the situation of the NTC in the lithium battery pack exceeding the preset temperature threshold, and can also count the number of times each NTC exceeds the preset temperature threshold. For positions that frequently (exceed the preset number of times) exceed the preset temperature threshold, timely maintenance can be carried out to reduce abnormal situations.

[0044] The protection execution unit A consists of several sets of fans, and the installation positions of these fans correspond to the positions of the mechanical temperature switches. When the mechanical temperature switch of the secondary temperature protection unit is triggered, the corresponding fans are turned on synchronously to cool the battery surface at the corresponding position.

[0045] The protection execution unit B consists of several sets of cooling chips, and the installation positions of these cooling chips correspond to the installation positions of the NTC. When the NTC exceeds the preset temperature threshold in the first-level temperature protection unit, the corresponding cooling chips are activated simultaneously to cool the battery surface at the corresponding position.

[0046] The emergency protection mechanism consists of a fire detection device and a fire extinguishing device. The fire detection device is a smoke sensor, and the fire extinguishing device is a fire extinguisher. When the fire detection device, the primary temperature protection unit, and the secondary temperature protection unit are all triggered, the main control chip controls the fire extinguishing device to start emergency fire extinguishing.

[0047] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A lithium battery pack intelligent protection system based on multi-level temperature monitoring, characterized in that, It includes a primary temperature protection unit at the main control chip level and a secondary temperature protection unit at the hardware level; the primary temperature protection unit includes multiple NTCs connected to the main control chip; the secondary temperature protection unit includes multiple mechanical temperature switches TS directly connected in series between the charging MOSFET and the main control chip. 1~n。 2. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, Three high-precision NTCs, NTC1, NTC2, and NTC3, are used to connect to the main control chip. NTC1 and NTC2 are arranged at the center of the geometric surface of the battery pack, while NTC3 is arranged close to the heat dissipation area of ​​the power device.

3. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, The main control chip used is the SH3676016.

4. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, The three high-precision NTC signals are input to the SH3676016 main control chip after being filtered by RC and decoupled by a decoupling capacitor, with a sampling frequency of 1kHz.

5. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, The capacitance of the decoupling capacitor is 0.1μF.

6. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, The mechanical temperature switch TS 1~n Select the TS-223 temperature switch; the default state is normally closed.

7. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, Mechanical temperature switch TS 1~n It is mounted on the surface of the battery pack, and its mounting position covers the geometric center of the battery pack and the heat dissipation area of ​​the power devices.

8. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 1, characterized in that, The main control chip is connected to the MCU and the emergency protection mechanism; the secondary temperature protection unit is connected to the status indication unit A and the protection execution unit A, and the primary temperature protection unit is connected to the protection execution unit B and the status indication unit B; the status indication unit A, the protection execution unit A, the protection execution unit B, and the status indication unit are all connected to the main control chip.

9. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 8, characterized in that, The status indicator unit A and status indicator unit B are both status indicator lights; the protection execution unit A consists of several sets of fans, the installation positions of which correspond to the positions of the mechanical temperature switches; the protection execution unit B consists of several sets of cooling chips, the installation positions of which correspond to the installation positions of the NTC.

10. The intelligent protection system for lithium battery packs based on multi-level temperature monitoring according to claim 9, characterized in that, The emergency protection mechanism consists of fire detection devices and fire extinguishing equipment.

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