Compact Lithium-Ion Battery Pack for Engine Starting
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Solution Overview
Problem
Existing compact engine starting devices face challenges in efficiently and reliably starting engines using compact batteries, particularly due to the need for multiple batteries to achieve sufficient voltage and the limitations in reducing size and weight, while also ensuring sufficient discharging capacity for the ignition circuit and fuel supply control.
Innovation Solution
A battery pack utilizing lithium-based secondary batteries with a high-speed reducer mechanism, integrated protection circuits, and an automatic choke system, which includes an overdischarge inhibit circuit, overheat prevention, and an electronic circuit for safe and efficient engine starting, allowing for a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple compact batteries are used to achieve sufficient voltage, then the voltage requirement is met, but the size and weight of the battery pack increase
Solution Approach 1:
The patent applies parameter changes by switching from conventional battery chemistry to lithium-ion battery chemistry, which provides significantly higher voltage and energy density per unit mass. This allows achieving sufficient voltage for engine starting without requiring multiple batteries, thereby reducing overall battery pack weight and size while meeting the power requirements.
2Power
If multiple compact batteries are used to achieve sufficient voltage, then the voltage requirement is met, but the volume of the battery pack increases
Solution Approach 1:
The patent utilizes parameter changes by adopting lithium-ion battery technology which offers superior volumetric energy density compared to conventional batteries. This enables the battery pack to achieve the required voltage and capacity in a more compact form factor, reducing the overall volume occupied by the battery system.
3Volume of stationary object
If the battery pack is reduced in size, then compactness is improved, but the discharging capacity for ignition circuit and fuel supply control may be insufficient
Solution Approach 1:
The patent applies parameter changes by utilizing the high specific energy and high power density characteristics of lithium-ion batteries. These inherent parameters enable the battery pack to deliver sufficient discharging capacity for ignition circuit and fuel supply control systems while maintaining a compact size, thus resolving the contradiction between size reduction and reliability maintenance.
4Power
If high discharge current is provided for engine starting, then the starting power is sufficient, but overheating may occur
Solution Approach 1:
The patent replaces mechanical/chemical battery systems with lower thermal management capability with lithium-ion battery technology that has superior electrical conductivity and thermal characteristics. Combined with electronic control systems, this substitution enables high discharge current delivery for sufficient starting power while managing heat generation more effectively.
Solution Approach 2:
The patent implements feedback control through temperature sensing and management systems that monitor battery temperature during high-power discharge operations. When temperature thresholds are approached, the control system adjusts discharge parameters to prevent overheating, allowing sustained high starting power while maintaining thermal safety.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a high-performance, compact, and safe battery pack that efficiently starts engines with reduced size and weight, ensuring stable discharging and preventing overheating, thus enhancing the reliability and durability of the starting device.
Implementation Method 1
a lithium-based secondary battery comprising at least two cells
Implementation Method 2
a compact electric motor which is driven by the battery and which is rotated in a power accumulating direction
Implementation Method 3
a spiral spring having a spiral spring barrel which is driven and wound by a worm gear
Implementation Method 4
an overcurrent preventing circuit and a protection circuit comprising an electronic circuit such as an overcharge preventing circuit, an overdischarge inhibit circuit
Data Source
AI summary
This invention provides a battery pack for driving a compact electric motor of a compact engine starting device mounted on a working machine, comprising lithium-based secondary battery comprising two cells, the entire discharge capacity of the cells being 500 to 2000 mAh, charging voltage per one cell being 3.0 to 4.2 V, various electronic circuits like driving and battery protection circuits of an electric motor, maximum discharge current of the battery having high rate of 10 to 60 A, the protection circuit including an overdischarge inhibit circuit (A) interposed in the electric motor driving circuit and automatically stopping the driving operation of the electric motor after time required for starting the engine elapsed, the volume of the battery pack being as extremely low as 2.5×104 to 1.0×105 mm3, the tire required until the engine is started from the actuation of the electric motor being set to an interval as short as 5 to 15 seconds, since high current can flow.