CN117345701A - Efficient nitrogen charging device and method for energy accumulator - Google Patents

Abstract

The invention belongs to the field of energy storage equipment, and particularly relates to a high-efficiency nitrogen charging device of an energy accumulator, which comprises a nitrogen component, wherein the nitrogen component comprises a nitrogen supply device and an air inlet one-way valve for allowing nitrogen in the nitrogen supply device to flow into other parts of the device; the device is provided with a multi-cavity piston, the multi-cavity piston comprises a main cavity, a piston capable of reciprocating is arranged in the main cavity, the piston divides the main cavity into a plurality of sub-cavities, each sub-cavity comprises a plurality of air inlet cavities communicated with a nitrogen component and an energy accumulator, and an air charging one-way valve capable of enabling air in the air inlet cavities to flow into the energy accumulator is arranged between the air inlet cavities and the energy accumulator; the apparatus further includes a power source for driving the piston to reciprocate in the general chamber. According to the invention, an active return nitrogen charging scheme is adopted, even if the pressure of nitrogen in the nitrogen supply device is low, the piston actively moves to expand the air inlet cavity, so that the nitrogen in the nitrogen supply device can flow into the air inlet cavity due to the pressure difference, the nitrogen in the nitrogen supply device is fully utilized, and the nitrogen charging efficiency is increased.

Description

Efficient nitrogen charging device and method for energy accumulator

Technical Field

The invention belongs to the field of energy storage equipment, and particularly relates to a high-efficiency nitrogen charging device and method for an energy storage device.

Background

A hydraulic accumulator is a device that stores energy. In an accumulator, the stored energy is stored in the form of compressed gas, a compression spring or a lifting load, exerting a force on a relatively incompressible fluid.

Accumulators are very useful in fluid dynamic systems to store energy, eliminating pulses. They may be used in hydraulic systems to reduce the gauge of fluid pumps by replenishing the fluid of the pump. This is accomplished by storing energy in the pump during low demand periods. They can act as a wave and pulse dampening and absorber. They can buffer the impact and reduce vibrations in the hydraulic circuit caused by sudden activation or deactivation of the power cylinder. The accumulator may be used in the hydraulic system to stabilize pressure changes when the fluid is affected by temperature increases and decreases. They can dispense pressurized fluids such as grease and lubricating oil.

The most commonly used accumulators are currently of the pneumatic-hydraulic type. The gas acts like a buffer spring, which cooperates with the fluid; the gas is separated by a piston, a thin diaphragm or a balloon.

The volume of the liquid changes very slightly under the action of pressure (in the case of constant temperature), so that if there is no power source (i.e. replenishment of the high-pressure liquid), the pressure of the liquid will drop rapidly. The elasticity of the gas is much greater because the gas is compressible and it is still possible for the gas to maintain a relatively high pressure with a large volume change. Therefore, when the accumulator is used for supplementing the hydraulic oil of the hydraulic system, under the condition that the volume of the liquid is changed, the high-pressure gas can continuously maintain the pressure of the hydraulic oil, and the phenomenon that the volume of the hydraulic oil in the container is reduced due to the supplementation of the hydraulic oil, so that the hydraulic oil is rapidly depressurized is avoided. As for nitrogen, the main reason is that nitrogen is stable in property, does not have oxidation or reduction properties, and is very advantageous for maintaining the performance of hydraulic oil, and does not cause oxidation/reduction denaturation of hydraulic oil.

The nitrogen is a pre-charge pressure, and is contained in the bladder of the accumulator, isolated from the hydraulic oil. When you fill the accumulator with hydraulic oil, because the pressure effect of nitrogen gasbag to the hydraulic oil, the pressure of hydraulic oil equals nitrogen gas pressure promptly, along with the hydraulic oil dashes into, nitrogen gas gasbag is compressed, nitrogen gas pressure increases, and the pressure of hydraulic oil follows the increase, until the hydraulic oil fills to the pressure of settlement. The accumulator is used for providing hydraulic oil with certain pressure, and the hydraulic oil is generated by acting force of nitrogen.

High-pressure casting refers to a method of filling liquid or semi-solid metal into a mold cavity under high pressure and speed, and performing pressure-maintaining cooling and solidification molding. The injection speed of high-pressure casting is very fast, and only the power unit of the oil pump motor is difficult to meet the requirement, and the injection speed is generally ensured by filling and discharging liquid through an energy accumulator.

The nitrogen charging method used in the prior art is pushed by hydraulic oil when the piston moves upwards, the downward return movement is passive reset by the thrust of nitrogen, the external nitrogen source pressure is not constant, the piston reset speed is greatly influenced by the external nitrogen source pressure and the return oil back pressure of the nitrogen charging hydraulic valve, when the external nitrogen source pressure is lower, the nitrogen charging efficiency is very low or nitrogen cannot be charged, and the nitrogen cylinder needs to be replaced before the external nitrogen source pressure is reduced to 2MPa, so that the nitrogen utilization rate is low.

Disclosure of Invention

Aiming at the defects of low nitrogen charging efficiency and low nitrogen utilization rate when the external nitrogen source pressure is low in the prior art, the invention firstly provides a high-efficiency energy accumulator nitrogen charging device to overcome the defects, and the specific technical scheme is as follows:

an efficient accumulator nitrogen charging apparatus, comprising:

the nitrogen component comprises a nitrogen supply device and an air inlet one-way valve which allows nitrogen in the nitrogen supply device to flow into other parts of the device;

the multi-cavity piston comprises a main cavity, a piston capable of reciprocating is arranged in the main cavity, the piston divides the main cavity into a plurality of sub-cavities, each sub-cavity comprises a plurality of air inlet cavities communicated with the nitrogen component and the energy accumulator, and an air charging one-way valve capable of enabling air in the air inlet cavities to flow into the energy accumulator is arranged between the air inlet cavities and the energy accumulator;

and the power source is used for driving the piston to reciprocate in the total chamber.

According to the device provided by the invention, a novel active return nitrogen charging scheme is adopted, nitrogen in the nitrogen feeder flows into the air inlet cavity, the power source drives the piston to reciprocate in the main cavity, nitrogen is pressed out of the air inlet cavity when the piston is pressed into the air cavity, nitrogen can be pressed into the energy accumulator for charging nitrogen in the energy accumulator due to the existence of the air inlet one-way valve, when the piston moves and the air inlet cavity expands, nitrogen in the nitrogen feeder flows into the air inlet cavity through the air inlet one-way valve, when the nitrogen pressure in the nitrogen feeder is lower, the piston actively moves to expand the air inlet cavity, the nitrogen pressure in the air inlet cavity becomes lower, and the nitrogen in the nitrogen feeder is driven to flow into the air inlet cavity due to pressure difference, so that the nitrogen in the nitrogen feeder is fully utilized, and the nitrogen charging efficiency is increased.

Further, the power source comprises an oil source for providing oil, an oil tank and a reversing valve capable of controlling the oil flow among the oil source, the oil tank and the liquid inlet cavity.

Further, the reversing valve is an electromagnetic valve.

Further, the total chamber further comprises a liquid inlet cavity, the liquid inlet cavity comprises a first liquid inlet cavity and a second liquid inlet cavity which are separated, the air inlet cavity comprises a first air inlet cavity and a second air inlet cavity, the first liquid inlet cavity, the second liquid inlet cavity and the second air inlet cavity are sequentially arranged, the piston comprises a first piston and a second piston, the first liquid inlet cavity is separated from the first air inlet cavity through the first piston, the second liquid inlet cavity is separated from the second air inlet cavity through the second piston, and the first piston is fixedly connected with the second piston.

Further, the multi-cavity piston further comprises a liquid inlet cavity, the liquid inlet cavity comprises a first liquid inlet cavity and a second liquid inlet cavity, the liquid inlet cavity comprises a first air inlet cavity and a second air inlet cavity which are separated, the first liquid inlet cavity, the first air inlet cavity, the second air inlet cavity and the second liquid inlet cavity are sequentially arranged, the piston comprises a first piston and a second piston, the first liquid inlet cavity is separated from the first air inlet cavity through the first piston, the second liquid inlet cavity is separated from the second air inlet cavity through the second piston, and the first piston is fixedly connected with the second piston.

The device is hydraulically driven, and the reversing valve is used for controlling the communication state of an oil source and an oil tank with a first liquid inlet cavity and a second liquid inlet cavity, and comprises the following three states: the oil source is communicated with the first liquid inlet cavity, and the oil tank is communicated with the second liquid inlet cavity; the oil source is communicated with the second liquid inlet cavity, and the oil tank is communicated with the first liquid inlet cavity; the first liquid inlet cavity and the second liquid inlet cavity are communicated with the oil tank. When the oil source is communicated with the first liquid inlet cavity, the oil tank is communicated with the second liquid inlet cavity, oil enters the first liquid inlet cavity, oil in the second liquid inlet cavity flows out of the oil tank, the oil pushes the first piston to move, the first liquid inlet cavity expands to compress the first liquid inlet cavity, nitrogen in the first liquid inlet cavity is pressed into the energy accumulator to charge nitrogen in the energy accumulator, and the second piston moves along with the first piston due to the fixed connection of the first piston and the second piston, so that the second liquid inlet cavity expands, and the second liquid inlet cavity sucks nitrogen. The reversing valve is controlled to be in a switching state, the oil source is communicated with the second liquid inlet cavity, the oil tank is communicated with the first liquid inlet cavity, oil in the first liquid inlet cavity flows out of the oil tank, the oil enters the second liquid inlet cavity, the oil pushes the second piston to move, the second liquid inlet cavity expands to compress the second liquid inlet cavity, nitrogen in the second liquid inlet cavity is pressed into the energy accumulator, nitrogen charging of the energy accumulator is carried out, the first piston moves along with the second piston, the first air inlet cavity expands, and the first air inlet cavity sucks nitrogen. The switching between the two states ensures that the whole device charges nitrogen into the energy accumulator like an inflator, and can actively pump out the nitrogen even when the nitrogen pressure of the nitrogen feeder is low, and in the process, due to the design of the multi-cavity piston, the nitrogen charging of the energy accumulator and the air inlet of the air inlet cavity are simultaneously carried out, so that the nitrogen charging efficiency is improved.

Further, the nitrogen charging device comprises a first nitrogen component and a second nitrogen component, wherein the first nitrogen component is communicated with the first air inlet cavity, and the second nitrogen component is communicated with the second air inlet cavity.

Further, a stop valve is arranged between the nitrogen supply device and the air inlet one-way valve.

Further, the first nitrogen component and the second nitrogen component are communicated with each other between the stop valve and the air inlet check valve.

The invention is provided with two groups of nitrogen components which are respectively communicated with the first air inlet cavity and the second air inlet cavity so as to supply nitrogen to the two air inlet cavities, and the stop valve and the two nitrogen components are communicated, so that each group of nitrogen components can supply nitrogen to the two air inlet cavities, and when the nitrogen pressure in the nitrogen supply device of one nitrogen component is insufficient, the stop valve can block the communication between the nitrogen supply device with insufficient pressure and other parts of the device, and the replacement of the nitrogen supply device can not influence the use of the device at the moment so as to improve the nitrogen charging efficiency of the device.

The device can also only use a set of nitrogen component at the same moment, makes another nitrogen component of group not participate in the work through the stop valve, when the nitrogen component nitrogen pressure of participating in filling nitrogen is low, utilizes the switching of two stop valve switches, makes nitrogen component that nitrogen pressure is low and other parts of device not communicate, makes another nitrogen component of group who does not participate in the work originally link into the device, changes the nitrogen component that nitrogen pressure is low this moment, can not influence the normal use of device, has improved the nitrogen filling efficiency of this device.

Further, a sensor and a pressure gauge are arranged in the device to detect the pressure of the gas in the energy accumulator, and when the sensor and the pressure gauge detect that the pressure of the energy accumulator reaches a set value, the nitrogen charging is completed, and the nitrogen charging is stopped.

Further, a sensor is arranged in the device to detect the pressure of the gas in the nitrogen supply device, and the nitrogen supply device is replaced when the sensor detects that the pressure in the nitrogen supply device is too low.

Further, the nitrogen supply device of the device is one to a plurality of nitrogen cylinders.

The invention further provides a nitrogen charging method for the energy accumulator based on the device, which comprises the following steps of:

s1: nitrogen in the nitrogen cylinder is introduced into the air inlet cavity;

s2: the power source drives the piston to move, so that nitrogen in the air inlet cavity is pressed into the energy accumulator by the piston;

s3: and repeating the steps S1 and S2 until the nitrogen charging of the energy accumulator is completed.

The invention has the following beneficial effects:

(1) According to the invention, a nitrogen charging scheme of an active return stroke is used, the piston is actively driven to move, nitrogen is pumped out by utilizing pressure difference, and the nitrogen can be fully utilized when the nitrogen pressure of the nitrogen feeder is low;

(2) According to the invention, the arrangement of the multi-cavity piston and the switching of the reversing valve to the liquid inlet state enable the nitrogen charging of the energy accumulator and the air inlet of the air inlet cavity to be carried out simultaneously, so that the nitrogen charging efficiency is increased;

(3) According to the invention, the stop valve and the two nitrogen components are communicated, so that each group of nitrogen components can supply nitrogen to the two air inlet cavities, and the replacement of the nitrogen supply device can not affect the use of the device, so that the nitrogen charging efficiency of the device is improved.

Drawings

Fig. 1: the invention relates to a high-efficiency nitrogen charging device of an energy accumulator, which is shown in an embodiment 1.

Fig. 2: the invention relates to an embodiment 2 schematic diagram of a high-efficiency nitrogen charging device of an energy accumulator.

Fig. 3: comparative example 1 of the prior art of an accumulator nitrogen charging device is schematically illustrated.

Wherein: the device comprises an energy accumulator, a nitrogen component 1, a nitrogen supply device 11, a gas inlet one-way valve 12, a first nitrogen component 13, a second nitrogen component 14, a stop valve 15, a sensor 16, a pressure gauge 17, a multi-cavity piston 2, a total cavity 21, a piston 22, a sub-cavity 211, a gas inlet cavity 212, a gas charging one-way valve 213, a liquid inlet cavity 214, a first piston 221, a second piston 222, a first gas inlet cavity 2121, a second gas inlet cavity 2122, a first liquid inlet cavity 2141, a second liquid inlet cavity 2142, a power source 3, an oil source 31, a 32 oil tank 33 and a reversing valve 33.

Detailed Description

The invention is further described below in connection with specific embodiments. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. In addition, the embodiments of the present invention referred to in the following description are typically only some, but not all, embodiments of the present invention. Therefore, all other embodiments, which can be made by one of ordinary skill in the art without undue burden, are intended to be within the scope of the present invention, based on the embodiments of the present invention.

Example 1

As shown in fig. 1, an efficient nitrogen charging device for an accumulator 01 includes two groups of nitrogen components 1, each nitrogen component 1 includes a first nitrogen component 13 and a second nitrogen component 14, each group of nitrogen components 1 includes a nitrogen supply device 11, an air inlet check valve 12 for allowing nitrogen in the nitrogen supply device 11 to flow into other parts of the device, the nitrogen supply device 11 is a nitrogen cylinder, an air inlet check valve 12 is arranged at an outlet of the nitrogen cylinder, and safety of operators is protected when the nitrogen cylinder is replaced.

The device is provided with a multi-cavity piston 2, the multi-cavity piston 2 comprises a total cavity 21, a piston 22 capable of reciprocating is arranged in the total cavity 21, the piston 22 divides the total cavity 21 into a plurality of sub-cavities 211, the sub-cavities 211 comprise a plurality of air inlet cavities 212 communicated with the nitrogen component 1 and the energy accumulator 01, the sub-cavities 211 further comprise a liquid inlet cavity 214, the liquid inlet cavities 214 comprise a first liquid inlet cavity 2141 and a second liquid inlet cavity 2142 which are separated, the air inlet cavities 212 comprise a first air inlet cavity 2121 and a second air inlet cavity 2122, the first air inlet cavity 2121, the first liquid inlet cavity 2141, the second liquid inlet cavity 2142 and the second air inlet cavity 2122 are sequentially arranged, the piston 22 comprises a first piston 221 and a second piston 222, the first liquid inlet cavity 2141 is separated from the first air inlet cavity 2121 by the first piston 221, the second liquid inlet cavity 2142 is separated from the second air inlet cavity 2122 by the second piston 222, and the first piston 221 is fixedly connected with the second piston 222. An air charging check valve 213 is arranged between the air inlet cavity 212 and the accumulator 01, so that the air in the air inlet cavity 212 can flow into the accumulator 01. The first nitrogen component 13 is communicated with the first air inlet cavity 2121, the second nitrogen component 14 is communicated with the second air inlet cavity 2122, the first nitrogen component 13 and the second nitrogen component 14 are communicated with each other at a position between the stop valve 15 and the air inlet check valve 12, and the stop valve 15 is arranged between the nitrogen supplier 11 and the air inlet check valve 12.

The device further comprises a power source 3 for driving the piston 22 to reciprocate in the main chamber 21, wherein the power source 3 comprises an oil source 31 for providing oil, an oil tank 32 and a reversing valve 33 for controlling the oil flow among the oil source 31, the oil tank 32 and the liquid inlet cavity 214, and the reversing valve 33 is an electromagnetic valve.

The device is provided with the sensor 16 and the pressure gauge 17 to detect the pressure of the gas in the accumulator 01, and when the sensor 16 and the pressure gauge 17 detect that the pressure of the accumulator 01 reaches a set value, the nitrogen charging is completed, and the nitrogen charging is stopped. The present apparatus is provided with a sensor 16 for detecting the pressure of the gas in the nitrogen supplier 11, and the replacement of the nitrogen supplier 11 is performed when the sensor 16 detects that the pressure in the nitrogen supplier 11 is too low.

The oil passage is connected in the connection shown in fig. 1, the left stop valve 15 is opened, and the right stop valve 15 is closed. When the left electromagnet and the right electromagnet of the reversing valve 33 are not electrified, the electromagnetic valve is in the middle position, the piston 22 does not move, and the system is in a pressure release state and does not perform nitrogen charging action; when the reversing valve 33 is powered on to the left, the oil provided by the oil source 31 enters the second liquid inlet cavity 2142 of the multi-cavity piston 2 through the reversing valve 33, the piston 22 moves to the right under the action of the oil, the nitrogen in the second liquid inlet cavity 2122 enters the accumulator 01 through the charging check valve 213, the nitrogen in the right nitrogen feeder 11 enters the first liquid inlet cavity 2121 of the multi-cavity piston 2 through the bottle opening check valve, the right stop valve 15 and the air inlet check valve 12, and the oil in the second liquid inlet cavity 2142 returns to the oil tank 32 through the reversing valve 33. When the reversing valve 33 is powered on to the right, the oil provided by the oil source 31 enters the first liquid inlet cavity 2141 of the multi-cavity piston 2 through reversing, the piston 22 moves to the left under the action of hydraulic oil, gas in the first liquid inlet cavity 2121 enters the accumulator 01 through the charging one-way valve 213, nitrogen in the nitrogen feeder 11 enters the second liquid inlet cavity 2122 of the multi-cavity piston 2 through the bottle opening one-way valve, the stop valve 15 and the air inlet one-way valve 12, and the oil in the second liquid inlet cavity 2142 returns to the oil tank 32 through the reversing valve 33. When the right sensor 16 detects that the pressure of the right nitrogen cylinder is lower than the set value, a low-pressure alarm prompt is made. The operator firstly opens the left stop valve 15 to enable the nitrogen cylinder to work, then closes the right stop valve 15, and replaces the nitrogen cylinder with low nitrogen pressure with a new nitrogen cylinder with high pressure; similarly, when the left sensor 16 detects that the pressure of the left nitrogen gas cylinder is too low, an operator opens the right stop valve 15 to enable the right nitrogen gas cylinder to work, closes the left stop valve 15, and replaces the nitrogen gas cylinder with low nitrogen gas pressure with a new nitrogen gas cylinder with high pressure. When the sensor 16 detects that the accumulator 01 pressure reaches the set value, the nitrogen charging is completed, and the nitrogen charging is stopped.

Example 2

This embodiment is identical to the implementation of embodiment 1, except that: as shown in fig. 2, the multi-cavity piston 2 includes a liquid inlet cavity 214, the liquid inlet cavity 214 includes a first liquid inlet cavity 2141 and a second liquid inlet cavity 2142, the air inlet cavity 212 includes a first air inlet cavity 2121 and a second air inlet cavity 2122 which are separated, the first liquid inlet cavity 2141, the first air inlet cavity 2121, the second air inlet cavity 2122 and the second liquid inlet cavity 2142 are sequentially arranged, the piston 22 includes a first piston 221 and a second piston 222, the first liquid inlet cavity 2141 and the first air inlet cavity 2121 are separated by the first piston 221, the second liquid inlet cavity 2142 and the second air inlet cavity 2122 are separated by the second piston 222, and the first piston 221 is fixedly connected with the second piston 222.

Comparative example 1

As shown in FIG. 3, a nitrogen charging method is currently available. The device consists of an oil source 31, a reversing valve 33, a liquid inlet cavity 214, an air inlet cavity 212, a nitrogen supplier 11, an air inlet one-way valve 12, an air charging one-way valve 213, a piston 22, an energy accumulator 01 and an oil tank 32. The oil source 31 provides oil at a certain pressure and flow rate, and the oil can enter the liquid inlet cavity 214 through the reversing valve 33. In the initial state, the piston 22 is in an upper position, the reversing valve 33 is powered off, the reversing valve 33 is in a right position, the air inlet one-way valve 12 is opened under the pressure of nitrogen in the nitrogen feeder 11, the air in the nitrogen feeder 11 enters the air inlet cavity 212 through the air inlet one-way valve 12, the piston 22 moves downwards, and oil below the piston 22 returns to the oil tank 32. The reversing valve 33 is powered on, the reversing valve 33 is positioned at the left position, oil enters the liquid inlet cavity 214 through the reversing valve 33, the piston 22 moves upwards under the action of the oil, gas in the air inlet cavity 212 is compressed, the air inlet one-way valve 12 is kept closed under the action of gas pressure, the air charging one-way valve 213 is opened, and nitrogen enters the energy accumulator 01 to realize the nitrogen charging function. By repeating the above operation cycle, the nitrogen gas in the nitrogen supplier 11 can be continuously pressed into the accumulator 01. According to the method, only when the piston 22 moves upwards, the piston is pushed by oil, the downward return movement is passive reset by the pushing force of nitrogen, the resetting speed of the piston 22 is greatly influenced by the pressure of an external nitrogen source and the back pressure of the oil return of the nitrogen charging hydraulic valve because the pressure of the external nitrogen source is not constant, when the pressure of the external nitrogen source is low, the nitrogen charging efficiency is very low or nitrogen cannot be charged, and the nitrogen feeder 11 is required to be replaced before the pressure of the external nitrogen source is reduced to 2MPa, so that the nitrogen charging efficiency and the nitrogen utilization rate are low when the pressure of the external nitrogen source are low.

Claims (10)

1. An efficient accumulator nitrogen charging device which is characterized in that: comprising the following steps:

the nitrogen component (1) comprises a nitrogen supply device (11) and an air inlet one-way valve (12) which allows nitrogen in the nitrogen supply device (11) to flow into other parts of the device;

the multi-cavity piston (2) comprises a total cavity (21), a piston (22) capable of reciprocating is arranged in the total cavity (21), the piston (22) divides the total cavity (21) into a plurality of sub-cavities (211), the sub-cavities (211) comprise a plurality of air inlet cavities (212) communicated with the nitrogen component (1) and the energy accumulator, and an air charging one-way valve (213) capable of enabling air in the air inlet cavities (212) to flow into the energy accumulator is arranged between the air inlet cavities (212) and the energy accumulator;

-a power source (3), said power source (3) being adapted to drive a piston (22) to reciprocate in a general chamber (21).

2. An efficient accumulator nitrogen charging apparatus as claimed in claim 1, wherein: the total chamber (21) further comprises a liquid inlet cavity (214), the liquid inlet cavity (214) comprises a first liquid inlet cavity (2141) and a second liquid inlet cavity (2142) which are separated, the air inlet cavity (212) comprises a first air inlet cavity (2121) and a second air inlet cavity (2122), the first air inlet cavity (2121), the first liquid inlet cavity (2141), the second liquid inlet cavity (2142) and the second air inlet cavity (2122) are sequentially arranged, the piston (22) comprises a first piston (221) and a second piston (222), the first liquid inlet cavity (2141) and the first air inlet cavity (2121) are separated by the first piston (221), and the second liquid inlet cavity (2142) and the second air inlet cavity (2122) are separated by the second piston (222).

3. An efficient accumulator nitrogen charging apparatus as claimed in claim 1, wherein: the multi-cavity piston (2) further comprises a liquid inlet cavity (214), the liquid inlet cavity (214) comprises a first liquid inlet cavity (2141) and a second liquid inlet cavity (2142), the air inlet cavity (212) comprises a first air inlet cavity (2121) and a second air inlet cavity (2122) which are separated, the first liquid inlet cavity (2141), the first air inlet cavity (2121), the second air inlet cavity (2122) and the second liquid inlet cavity (2142) are sequentially arranged, the piston (22) comprises a first piston (221) and a second piston (222), the first liquid inlet cavity (2141) and the first air inlet cavity (2121) are separated by the first piston (221), and the second liquid inlet cavity (2142) and the second air inlet cavity (2122) are separated by the second piston (222).

4. A high efficiency accumulator charging apparatus according to any one of claims 2 or 3, wherein: the power source (3) comprises an oil source (31) for providing oil, an oil tank (32) and a reversing valve (33) capable of controlling the oil flow among the oil source (31), the oil tank (32) and the liquid inlet cavity (214).

5. The efficient accumulator nitrogen charging apparatus of claim 4, wherein: the reversing valve (33) is an electromagnetic valve.

6. A highly efficient accumulator nitrogen charging apparatus according to claim 2 or 3, characterized in that: the nitrogen charging device comprises a first nitrogen component (13) and a second nitrogen component (14), wherein the first nitrogen component (13) is communicated with the first air inlet cavity (2121), and the second nitrogen component (14) is communicated with the second air inlet cavity (2122).

7. A high efficiency accumulator charging apparatus according to any one of claims 2 or 3, wherein: the first piston (221) is fixedly connected with the second piston (222).

8. An efficient accumulator nitrogen charging apparatus as claimed in claim 1, wherein: a stop valve (15) is arranged between the nitrogen feeder (11) and the air inlet one-way valve (12).

9. The efficient accumulator nitrogen charging apparatus of claim 8, wherein: the first nitrogen component (13) and the second nitrogen component (14) are communicated with each other between the stop valve (15) and the air inlet one-way valve (12).

10. A method of charging an accumulator with nitrogen according to the apparatus of claim 1, characterized in that: the method comprises the following steps:

s1: nitrogen in the nitrogen feeder (11) is introduced into the air inlet cavity (212);

s2: the power source (3) drives the piston (22) to move, so that nitrogen in the air inlet cavity (212) is pressed into the energy accumulator by the piston (22);

s3: and repeating the steps S1 and S2 until the nitrogen charging of the energy accumulator is completed.