Cold start mechanism
Motorcycle cold start is the core challenge of the engine in the low temperature without preheating state, relying on the lithium battery to release ultra-high current instantaneously (usually need to provide more than 160A current in the -20℃ to 0℃ environment) to complete the ignition. This process not only tests the physical limits of the battery, but also involves the coordination of electrochemical, thermodynamic and electronic control systems. This section will reveal the underlying logic of lithium batteries to break through the low temperature performance bottleneck of traditional lead-acid batteries from the three aspects of material innovation, structural design and intelligent regulation.
Three technical challenges of low temperature cold start
1. Lithium ion migration resistance doubled
At -20℃, the viscosity of the electrolyte increases to 10 times that of normal temperature, and the diffusion rate of lithium ions decreases by 80%, resulting in a surge in internal resistance.
2. Passivation effect of electrode interface
The solid electrolyte interface (SEI) film on the negative electrode surface thickens at low temperature, preventing lithium ions from embedding in the graphite layer, resulting in capacity attenuation.
3. Steep instantaneous power demand
The starting motor needs to output more than 2kW in 5 seconds, which is equivalent to releasing more than 300W of instantaneous power per kilogram of battery.
Cold start core technology breakthrough
1. Microstructure design of power cell
The three-dimensional conductive network is constructed using a graphene-coated terpolymer (such as NCM811), which increases the positive electrode conductivity by 50%, and expands the ion channel through a honeycomb plate design, increasing the discharge efficiency from 40% to 75% at -20 ° C.
The composite negative electrode with 5% nano silicon particles is optimized to form more lithium ion embedding sites at low temperatures, avoid the formation of lithium dendrites, and increase the specific capacity to 450mAh/g (1.2 times that of traditional graphite).
2. Thermodynamic intervention of intelligent temperature control system
A 0.1mm thick ceramic heating film is embedded between the PTC self-heating film integrated cell, and the cell temperature is increased from -20℃ to 5℃ within 3 minutes by BMS control, and the lithium ion migration rate is restored to 85% of normal temperature.
The bidirectional liquid cooling cycle high-end battery pack is equipped with a glycol circulation pipeline, and the motor waste heat can be imported into the battery compartment when starting at a low temperature to achieve closed-loop energy utilization.
3. Dynamic regulation strategy of BMS
The volt-temperature coupling algorithm monitors the DC internal resistance (DCR) of each cell in real time, and automatically increases the discharge cutoff voltage from 2.5V to 2.8V when the environment below -10℃ is detected, compensating for the polarization loss.
The 50A pulse current is applied for 0.5 seconds before the start of the pulse preactivation technology, which promotes the dissociation of the electrolyte molecules and increases the ionic conductivity by 30%.
Conclusion
Through nanomaterials modification, adaptive thermal management and dynamic impedance matching, the lithium battery has successfully broken the "low temperature curse" of the motorcycle cold start.
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START-STOP LITHIUM battery
Enov start-stop battery is designed to provide excellent performance for high-demand start-stop vaehicles. It adopts the third-generation intelligent lithium platform architecture to achieve technological breakthroughs in core indicators such as cycle life, environmental adaptability and energy density. Compared with the traditional lead-acid battery system, the energy efficiency is increased by 210%, the cycle life is extended by 8-10 times, and the monthly self-discharge rate is controlled within 3%. Enov's unique low-temperature battery technology makes a breakthrough in achieving stable output in the whole climate domain from -30℃ to 65℃, maintaining more than 90% of the effective capacity release under extremely cold conditions (-30℃), and maintaining 90% of the capacity in high temperature environments (65℃).
The start-stop battery series products cover the mainstream voltage platform of 12V/24V/48V, and support flexible configuration of LFP (lithium iron phosphate) and NCM (lithium nickel cobalt manganese oxide) dual-material system. All models adopt modular design to support customization of different model specifications. Enuo engineering and technical team to provide full cycle technical service support, if you need, please contact us.
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