Top Battery Thermal Management Solutions Supplier and Manufacturer

Battery thermal management (BTM) involves actively or passively regulating the temperature of a battery pack to maintain it within the ideal operating range of 10°C–45°C. More advanced technical requirements also include controlling the temperature difference between each battery in the battery pack to below 5°C. Its core functions include cooling, heating, and temperature balancing, ensuring safe and efficient operation of the battery pack under various environmental conditions.

Its core objectives are:
1. Prevent thermal runaway: Avoid high temperatures triggering chain exothermic reactions (such as fires or explosions);
2. Optimise battery performance: Heat the battery pack at low temperatures to enhance discharge capacity and cool it at high temperatures to maintain power output;
3. Extend battery lifespan: Reduce temperature fluctuations that cause battery degradation (such as lithium plating or thickening of the SEI film).

Power batteries are the energy source for electric vehicles. During charging and discharging, the batteries themselves generate a significant amount of heat, leading to an increase in temperature. Elevated temperatures can affect various battery characteristics, such as internal resistance, voltage, state of charge (SOC), available capacity, charging/discharging efficiency, and battery lifespan.

Battery thermal effects also impact vehicle safety, performance, and battery cycle life. I will elaborate on these points in the following sections, so please continue reading. Therefore, battery thermal management is of utmost importance.

1 Temperature control accuracy: Minimise temperature differences between individual cells within the battery pack, with a maximum temperature difference of ≤5°C.
2 Temperature range control: Maintain the battery pack temperature within the optimal range of 10–45°C.
3 Energy efficiency ratio: Minimise the power consumption of the BTMS to reduce its impact on the vehicle’s range.
4 Suppression of thermal runaway: The BTMS prevents thermal runaway through temperature monitoring and rapid cooling, which is the core of safety.

Currently, the most reliable and practical solution for EV battery thermal management is liquid cooling technology. I will use liquid cooling as an example to explain.

1. Heat absorption (battery → coolant)
The heat generated during battery charging and discharging is transferred to the liquid cooling plate in contact with the battery via thermal conduction. The coolant flows through the microchannels inside the liquid cooling plate, absorbing heat through convective heat exchange, causing the coolant temperature to rise.
2. Heat transfer (coolant → radiator)
The heated coolant is driven by an electric water pump and transported through pipes to the radiator. The radiator dissipates the heat into the environment through forced air cooling, causing the coolant temperature to decrease.
3. Circulation
The cooled coolant returns to the liquid cooling plate, forming a closed-loop circulation.

In summary, its operating principle is based on the physical mechanisms of heat conduction and convective heat transfer, achieving the absorption, transfer, and dissipation of battery heat through a closed-loop coolant system.

There are various types of BTMS, and different companies have different designs. Therefore, the following are only the key components:
1 Heat transfer medium: air, coolant, phase change material, etc.
2 Heat exchange components: radiators, liquid cooling plates, heat pipes, etc.
3 Drive units: electric water pumps, fans, electromagnetic vibrators, etc.
4 Sensing and control: temperature sensors (monitoring cell/module temperatures), BMS control units (regulating flow rate/fan speed based on temperature feedback)
5 Accessory components: PTC heaters, insulation materials, thermal interface materials, etc.

Generally, there are two main types: active cooling and passive cooling. The main difference is whether energy consumption occurs. If energy consumption occurs, it is active cooling; if there is zero energy consumption, it is passive cooling.

The active cooling system includes the following:

1. Air-cooled cooling system

This system primarily utilises the principle of air convection to circulate air within the battery compartment. The circulating air carries away heat from the batteries, thereby lowering their temperature. Simultaneously, the air undergoes further heat exchange within the evaporator, where the refrigerant evaporates to reduce the temperature of the circulating air.Advantages: Simple system structure, low cost, and easy maintenance.
Disadvantages: Poor high-temperature heat dissipation performance, low low-temperature startup efficiency, and uneven stability between batteries.

2. Refrigerant direct cooling system

This system primarily utilises the latent heat of evaporation principle of refrigerants. An air conditioning system is established within the battery system, with cooling plates installed within the battery system. Refrigerant evaporates within the cooling plates, rapidly and efficiently removing heat from the battery system to achieve cooling.

Advantages: Simple structure, theoretically uniform temperature distribution, and good cooling performance;
Disadvantages: Currently, the technology is not yet mature, and commercialisation is unlikely in the short term.

3. Integration: Shared Water-Cooled Cooling System

A plate heat exchanger is added and coupled to the air conditioning system. The batteries exchange heat with the coolant through the cooling plates. The cooled or heated coolant is pumped into the plate heat exchanger, where refrigerant flows into one side and coolant flows into the other. Heat is removed by the refrigerant, and the coolant flows out of the plate heat exchanger and back into the batteries, completing the cycle.

Advantages: Compact structure, integrated battery heating components, high low-temperature start-up efficiency, excellent high-temperature cooling, and uniform temperature distribution.
Disadvantages: Multiple system components and complex control strategy.

4 Independent Battery Liquid Cooling System

When the battery needs cooling, it exchanges heat with the coolant through the cooling plate. The heated coolant is pumped into the plate heat exchanger by an electronic water pump. Inside the plate heat exchanger, refrigerant flows into one side and coolant flows into the other, where heat is exchanged. The heat is removed by the refrigerant, and the coolant flows out of the plate heat exchanger and back into the battery, completing the cycle.
When the battery needs heating, the cooling circuit is closed and the PTC liquid heater is activated. The heated coolant is then fed into the battery, where it heats the battery through the cooling plate. The internal battery temperature is controlled by controlling the cooling circuit and the PTC liquid heater.

Advantages: Compact structure, integrated battery heating components, high low-temperature starting efficiency, excellent high-temperature cooling, and uniform temperature distribution.
Disadvantages: Multiple system components and complex control strategy.

The independent battery liquid cooling system consists of a compressor, condenser, expansion valve, plate heat exchanger, electronic water pump, PTC liquid heater, expansion tank, and electrical control.

Passive cooling systems include the following:

1. Phase Change Material Battery Thermal Management (PCM-BTM)

This system utilizes the latent heat properties of phase change materials (PCMs), absorbing or releasing heat through solid-liquid phase transitions. It transfers heat through the physical properties of the material, eliminating the energy consumption of active cooling systems.

Advantages: No energy consumption, consistent temperature.
Disadvantages: Heavy weight, short lifespan.

2. Heat Pipe Technology

Heat pipe technology is a highly efficient thermal conductivity element that utilizes phase change in liquids for heat transfer. It consists of a tube shell, a wick, and end caps. A negative pressure is created inside the tube and filled with a low-boiling-point liquid. When one end is heated, the liquid evaporates and vaporizes. The vapor flows to the cold end, condensing and releasing heat. The condensed liquid then flows back to the evaporating end through capillary action, forming a cycle.

Advantages: No energy consumption, uniform temperature.
Disadvantages: High cost and complex design. It is primarily used in spacecraft equipment.

BTMS: Focuses on temperature control and is an execution subsystem of BMS.
BMS: Covers four major functions: status monitoring, electrical control (i.e., charging and discharging logic), thermal control (i.e., BTMS), and safety protection (insulation detection).In summary, the two systems collaborate to manage thermal control in electric vehicles by exchanging data and commands via the CAN bus. BTMS is the core subsystem of BMS, responsible for thermal safety boundary control. Without BMS and BTMS, the risk of battery malfunction significantly increases.

Ethylene glycol water solution, fluorinated liquid, deionised water, mineral oil, nanofluids, etc.

The generation of heat during charging and discharging is an unavoidable physical and chemical phenomenon. This is due to energy losses during the conversion process and the characteristics of the internal materials.
1 Joule heat — When current flows through the resistive components inside the battery, electrical energy is converted into thermal energy, in accordance with Joule’s law: Qj = I²Rt.
2 Reaction heat — The entropy change heat generated when lithium ions are inserted into or removed from the electrode.
3 Polarisation heat — Heat generated due to additional energy consumption caused by the obstruction of charge transfer on the electrode surface.

Localised overheating inside the battery triggers a chain reaction of exothermic reactions. The temperature rises rapidly by several hundred degrees per second to over 800 degrees, accompanied by pressure relief valve discharge and fire.

An increase in temperature affects both the usable capacity and cycle life of batteries.

Cycle life:
As can be seen from the two graphs, temperature has a significant impact on battery life. For the same battery cell, at an ambient temperature of 23°C, the remaining capacity after 6,238 days is 80%. If the battery is exposed to an ambient temperature of 55°C, the remaining capacity reaches 80% after only 272 days. A temperature increase of 32°C results in a 95% reduction in cell lifespan. As shown in the graph, the higher the temperature, the more severe the degradation of battery lifespan.

Available Capacity:
As shown in the two graphs, temperature also significantly affects a battery’s available capacity. For the same cell type, when the remaining capacity is 90%, the output capacity at 25°C is 300 kWh, while at 35°C, the output capacity is only 163 kWh. A 10°C increase in temperature results in a 45% decrease in the cell’s usable capacity.
Summary:
At low temperatures (<0°C), battery capacity drops by 30%–50%. This is due to increased electrolyte viscosity and reduced lithium-ion mobility. At high temperatures (>45°C), the cycle life accelerates and the risk of thermal runaway increases. This is due to the continuous thickening of the SEI film and the loss of active lithium. Further decomposition can lead to thermal runaway.
At temperature differences (>5°C), the effective capacity of the battery pack decreases by 10% to 30%. This is because the internal resistance of the battery is inconsistent, disrupting electrochemical consistency.

Currently, liquid cooling technology is the mainstream battery cooling method used in electric vehicles. It effectively balances heat dissipation efficiency, temperature uniformity, and cost. With breakthroughs in material innovation (such as nanofluids) and system integration (such as heat pump direct cooling), battery thermal management systems are evolving towards low energy consumption, lightweight design, and intelligent functionality. Forecasts suggest that the commercialisation of all-solid-state batteries by 2027 will drive contact-based phase-change cooling to become the mainstream. However, these are merely predictions, and given the rapid pace of technological development worldwide, only by strengthening one’s own R&D capabilities can one keep pace with the times.
TKT was established in 1998, and research and manufacturing of BTMS began in 2014. We have already collaborated with world-renowned automakers such as BYD and TATA Motors on customised development projects. If you are interested in battery thermal management, please feel free to leave a message for consultation.