Electric Vehicle (EV) Battery Temperature Sensor Supplier

Automotive battery temperature sensor, this issue is very critical in the field of new energy vehicles. In the previous section, we discussed automotive temperature sensors and exhaust temperature sensors. Now let’s focus on the core component of the battery. Users may be technicians or new energy vehicle owners who want to know the technical details of battery temperature monitoring.

Battery temperature sensors have three main technical characteristics: the most mainstream is NTC thermistor (hệ số nhiệt độ âm); the second is thin film platinum resistor (PT100/PT200); and there are emerging passive wireless sensors. It is necessary to focus on comparing their performance differences and application scenarios.

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Sensor layout strategy for square/cylindrical/soft pack batteries of automotive batteries. This is the pain point of the industry-different battery cell structures require customized solutions. Ví dụ, Tesla’s cylindrical battery uses a circumferential array, while BYD’s blade battery uses a top cover integration.

Safety should emphasize accuracy requirements, and the accuracy of ±0.5℃ is crucial for thermal runaway warning. Passive wireless technology is very interesting. It can solve the wiring problem in the battery pack by taking power through piezoelectric ultrasound or electromagnetic induction. This may be a future trend.

The impact of the failure also needs to be reminded, pointing out that failure of temperature monitoring may lead to thermal runaway.

Electric vehicle (EV) battery temperature sensors play a critical role in monitoring and managing the temperature of EV batteries, ensuring optimal performance, safety, and longevity. These sensors, often NTC thermistors, are crucial for detecting overheating and triggering safety measures like reducing charging rates or disconnecting the battery to prevent thermal runaway.

The following is a technical analysis of automotive battery temperature sensors, covering core principles, application solutions and development trends:
TÔI. Core functions and technical requirements
‌Precise temperature monitoring‌:
Real-time monitoring of battery module/cell temperature (usually in the range of -40℃~125℃), với độ chính xác ± 0,5 ℃, to prevent thermal runaway (trigger warning when temperature＞60℃).
High temperature may cause thermal runaway due to lithium ion decomposition, and the battery life will decrease by about 20% for every 10℃ increase in temperature.

Monitoring Battery Temperature:
EV battery temperature sensors continuously monitor the temperature of individual battery cells within the pack. This is vital because battery performance and lifespan are significantly affected by temperature.

Preventing Overheating:
Overheating can lead to reduced battery capacity, slower charging speeds, and even thermal runaway, potentially causing fires or explosions. Temperature sensors help prevent these issues by detecting overheating and initiating safety protocols.

Optimizing Performance:
By monitoring temperature, the battery management system (BMS) can adjust charging and discharging rates to maximize battery performance and lifespan.

Ensuring Safety:
Temperature sensors are a key part of the safety system in EVs, helping to prevent potentially dangerous situations like thermal runaway.

Common Types of Sensors:
NTC (Hệ số nhiệt độ âm) thermistors are commonly used as temperature sensors in EV batteries. They decrease their resistance as temperature increases, providing a reliable way to monitor temperature changes.

Location of Sensors:
Temperature sensors can be placed internally within battery cells for precise readings or externally on the battery pack to monitor surface temperatures.

Integration with BMS:
The data from temperature sensors is fed into the Battery Management System (BMS), which uses this information to control charging, discharging, and thermal management systems.
In essence, EV battery temperature sensors are a vital component of a safe, efficient, and high-performing electric vehicle.

Ii. Battery type and sensor layout strategy
‌Square battery cell (such as BYD blade battery)‌
‌Top cover pole area‌: NTC array is arranged within 5mm of the positive and negative poles to monitor the pole ear temperature (temperature difference ≈2-3℃).
‌Busbar welding point‌: Embedded sensor detects abnormal temperature rise at the connection point (＞5℃/min triggers protection).

‌Cylindrical battery cell (such as Tesla 4680)‌
‌End face ring array‌: NTC is evenly distributed on the circumference of the top cover to monitor the temperature gradient (error ±1.5℃).
‌Axial monitoring of winding core‌: NTC integrated in flexible PCB is inserted into the gap of winding core, and thermal runaway is warned 30 seconds in advance.

‌Soft-pack battery cell‌
Micro NTC (diameter 0.5mm) is pre-embedded and requires UL94 V0 grade insulation film packaging (thickness ≤ 0.1mm).

Iii. Technology evolution trend
‌Multi-dimensional fusion monitoring‌
Jiangxi Isuzu’s patented technology integrates temperature signals and vibration signals to generate a two-dimensional cloud map of temperature distribution and a time-frequency matrix to improve deformation prediction accuracy.

‌Passive wireless‌
CT power extraction or piezoelectric ultrasonic technology achieves self-powered power and eliminates wiring complexity (such as internal mounting of battery modules).

‌High-precision direct measurement technology‌
Continental’s eRTS technology reduces the temperature tolerance from 15℃ to 3℃, reduces the use of rare earths and improves motor control accuracy.

Iv. Failure risk and industry direction
‌Failure consequences‌: Monitoring failure may cause thermal runaway of the battery and cause a fire (thermal runaway trigger temperature > 150oC). ‌2025 Focus‌: Improve the density of single-cell monitoring, develop high-temperature resistant (>150°C) sensor materials, and NTC is still the main cost-sensitive field.

‌Note‌: The penetration rate of passive wireless solutions in new energy vehicles is expected to exceed 30% TRONG 2027, mainly replacing traditional wired sensors in high-voltage battery packs.