RU130145U1 - LITHIUM-ION BATTERY AND SAFETY VALVE FOR IT - Google Patents

Abstract

1. A lithium-ion battery containing an electrode block, consisting of a cathode and an anode, placed in a sealed case, which is a rectangular prism, at the base of which a rectangle lies, and a cover, in the holes of which a safety valve is installed, designed to relieve excess internal pressure in battery, and the terminals connected to the cathode and anode, characterized in that the battery case is made of reinforced fire-resistant fiberglass, and its walls are made in the form of a honeycomb structure, while the walls corresponding to the large sides of the base and their vertical joints have stiffeners, and the safety valve and terminals are secured in the cover with threaded connections. 2. The lithium-ion battery according to claim 1, characterized in that the terminals are attached to the battery housing cover by means of union nuts, and sealing ring gaskets made of rubber with a high content of silicone and rubber are installed between the terminals and the cover, ensuring the tightness of the connection. The lithium-ion battery according to claim 1, characterized in that the cathode terminal is made of aluminum and / or aluminum alloy. The lithium-ion battery according to claim 1, characterized in that the anode terminal is made of a copper-zinc alloy. The lithium-ion battery according to claims 1, 3 and 4, characterized in that the material from which the terminals are made has a nickel coating. The lithium-ion battery according to claim 1, characterized in that the material and construction of the housing ensure the battery operation in the temperature range from -25 ° C to + 50 ° C. The lithium-ion battery according to claim 1, characterized in that the battery cover

Description

FIELD OF TECHNOLOGY TO WHICH A USEFUL MODEL IS

The proposed technical solution relates to a utility model as an object of industrial property and relates to rechargeable chemical current sources, and more specifically to lithium-ion batteries, and can be used as an energy storage device in energy systems, as an energy source in transport, for example, in electric vehicles, in energy supply systems of buildings, as well as in household electronic equipment.

BACKGROUND

A lithium-ion battery consists of electrodes separated by electrolyte-impregnated porous separators. The electrodes are placed in a sealed enclosure and connected to the current collector terminals. The casing has a safety valve that relieves internal pressure in case of emergency and violation of operating conditions.

Prismatic lithium-ion batteries are known from the prior art (see RU No. 81381, RU No. 103375; RU No. 99247, etc.).

In a lithium-ion battery, according to utility model RU No. 99247, IPC H01M 10/0525, the housing is made in the form of a rectangular prism. The housing of the specified battery can be made of materials that can withstand chemical reactions that occur inside it, as well as hold the shape and prevent deformation of the device. In this case, the housing is made with the possibility of placing anode, cathode, separator, electrolyte, control circuit and temperature sensor in it. Possible execution in the housing of the corresponding holes for the conclusions from the cathode and anode.

Moreover, in lithium-ion batteries having a prismatic case, there is a problem of deformation of the case, which occurs under the influence of interelectrode pressure due to the thickening of the electrodes during cycling (RU No. 99323).

For reliable operation of the lithium-ion battery, it is also important to maintain a favorable temperature regime, as at temperatures above 40 ° C, the charge efficiency decreases, the degradation of the battery accelerates. A lithium-ion battery, in comparison with batteries of other electrochemical systems, has a high energy efficiency (90%), however, when used as part of a battery and in conditions close to adiabatic (in a closed volume), there is a need for artificial cooling, in connection with which it is desirable that the battery possesses a possibly higher heat transfer.

When using lithium-ion batteries in vehicles and in other conditions, they are subject to various dynamic loads, which can lead to electrolyte leakage, as well as the occurrence of a short circuit.

During cycling of lithium-ion batteries, its electrodes change their thickness depending on the state of charge, while over the course of several tens of initial cycles, a gradual increase in the thickness of the electrode blocks is observed, reaching 10-15% of the initial size. This phenomenon leads to an increase in interelectrode pressure, or to deformation of the body. This is especially pronounced on large prismatic batteries with flat walls. The walls become convex, which leads to uneven distribution of interelectrode pressure over the surface of the electrodes and, accordingly, their uneven operation. In order to avoid the aforesaid, the block of electrodes is made known to be of smaller thickness and the battery is freely assembled. Although this method allows avoiding deformation of the casing, it does not provide uniform distribution of interelectrode pressure, especially with a large number of electrodes in the block, when the absolute increase in the thickness of the block is tens of times greater than the thickness of the electrode pair.

A known design of a lithium-ion prismatic battery, in which to prevent deformation of the walls of the housing, the electrodes are parallel to the cover and the bottom (patent for utility model RU No. 69323). With this arrangement of the electrode block, the direction of the interelectrode pressure is normal to the bottom and cover, i.e. to the smallest in size and most rigid surfaces of the prismatic housing. However, with a large number of electrodes in the battery (tens, hundreds), the absolute value of the thickness increment reaches 10 mm or more. In this case, too “loose” assembly creates non-uniformity of interelectrode pressure both in different parts of interelectrode gaps and in different parts of electrode block, and too “rigid” assembly leads to an increase in interelectrode pressure, which, in turn, requires an increase in the strength of the housing , i.e. increase its mass and reduce energy characteristics.

Also known is a battery containing an elastic compensation element, which selects the assembly gap and provides electrical contact between the cover and one of the electrodes of the unit, as well as pressing electrodes of different signs through the separator to each other (Yu.P. Khranilov "Electrochemical energy conversion" 1979, pp. 44-45, Gorky University "). In this case, an elastic element, for example, a wave-shaped annular spring, or star-shaped stamping, changes its dimensions only within the limits of elastic deformation, and the absolute value of the possible change is commensurate with the thickness of the material from which the element is made.

The utility model RU No. 81381 is protected by a lithium-ion battery with a prismatic-shaped case, which incorporates a “thickening compensator”. The compensator is located between the housing and the electrode block, resting on the electrode block through the insulating gasket, and the battery housing with elastic elements, while the plane of the compensator and the working planes of the electrodes are parallel. The interelectrode pressure is balanced by the elastic properties of the compensator. If the pressure increases, then the compensator is compressed due to permanent deformation, thereby providing compensation for the increase in the size of the electrode block.

The disadvantage of these analogues is that they do not provide a constant in magnitude and uniform across the area of the electrode interelectrode pressure if the increase in the thickness of the electrode block is an order of magnitude or more greater than the thickness of the material of the elastic element. A disadvantage of the known technical solutions is also the obligatory electrical contact with the electrode and the relatively small area of this contact. The latter circumstance requires the use of a hard electrode, which are not the electrodes of a lithium-ion battery.

The closest of the listed batteries to the claimed object is a lithium-ion battery, consisting of a cathode and anode placed in a sealed enclosure, which is a rectangular prism, at the base of which is a rectangle, and a cover, in the openings of which there is a safety valve designed to discharge excess internal pressure in the battery, and terminals connected to the cathode and anode (RU No. 81381).

Such a technical solution, for all its simplicity, does not allow for reliable battery operation, especially under extreme mechanical and current loads.

Common disadvantages of the above analogues are:

- insufficiently used internal volume, which reduces the battery capacity;

- issues related to the emerging interelectrode pressure have not been resolved;

- The issues of cooling the case (heat removal) have not been resolved;

- the issue of safety and reliability in the event of a short circuit has not been resolved.

All of these shortcomings reduce the reliability and safety of the battery.

The increase in internal pressure in the battery, leading to its bloating, can be caused by the release of gases inside the battery case when the moisture content of the electrolyte solution in the battery exceeds the permissible value. For example, for a lithium battery according to the patent RU №2107360 moisture content of the organic electrolyte solution should be in the range of from 5 mn ^-1 (ppm) to 450 mn ^-1, preferably 15-300 mn ^-1. The explosion hazard of the battery is also associated with the release of heat inside the battery case during recharging.

A number of designs of lithium batteries contain complex safety devices, the so-called PTC elements (NTK elements with a positive temperature coefficient) are elements that operate at a temperature of 80-140 ° C (RU No. 2107360).

A more reliable and simple solution is to use a safety valve device in the batteries, which relieves the internal pressure in emergency situations and in violation of operating conditions.

Depending on the particular design of the safety valves, providing an effective pressure relief exceeding the permissible inside the battery chamber, they can ensure the exclusion of the so-called compensators from the design and, thus, make more full use of the internal volume of the battery and increase its capacity.

The prior art designs of safety valves for sealed batteries (SU No. 864388; SU No. 1383454; RU No. 2030819; RU No. 2082260; RU No. 2107360; RU No. 2402838 and others).

The principle of operation of many safety valves in sealed batteries, incl. lithium-ion, based on the deforming properties of elastic elements used as locking elements of the valve, which provide the opening or closing of the valve and the release of excess pressure of gases formed in the sealed battery case (for example, SU No. 1383454; RU No. 2030819; RU No. 2402838) .

In addition, the disadvantage of lithium-ion batteries with free electrolyte is that they are at risk of electrolyte loss. This can occur, for example, during manipulations with the battery during its transportation or due to an accident in which the vehicle in which such a battery is installed. Such a disadvantage is easily manifested also if the battery takes an inclined or inverted position.

The above-mentioned known valves do not solve the problems associated with the leakage of electrolyte from the battery, as well as related to the influence on its operation of harmful atmospheric effects, namely increased moisture content in the air. All these problems increase the explosiveness of the battery and reduce its reliability and safety.

DISCLOSURE OF A USEFUL MODEL

The task, which is aimed by the claimed device, is to increase the reliability and safety of the battery.

The task, in terms of the first object, a lithium-ion battery, consisting of a cathode and anode, placed in a sealed enclosure, which is a rectangular prism, at the base of which lies a rectangle, and covers, in the openings of which are installed a safety valve designed to discharge excess internal pressure in the battery, and the terminals attached to the cathode and anode, is solved due to the fact that the battery case is made of hardened fire-resistant fiberglass, and its walls are made in the form of tovoy structure wherein the walls corresponding to the large base of the sides and their vertical joints are stiffening ribs, and the safety valve and the terminals are secured in the cover by means of threaded connections.

In this case, the terminals can be attached to the cover of the battery case with ring nuts, and between the terminals and the cover can be installed sealing ring gaskets made of rubber with a high content of silicone and rubber, ensuring a tight connection.

In addition, the cathode terminal can be made of aluminum and / or aluminum alloy, and the anode terminal is made of copper-zinc alloy

In this case, the material from which the terminals are made may have a nickel coating.

The material and design of the case can provide battery operation in the temperature range from -25 ° С to + 50 ° С.

Also, an identification mark indicating the anode terminal may be mounted on the battery cover.

The problem, in part of the second object, the safety valve of a lithium-ion battery, containing a housing with a channel for the entrance of gases formed inside the battery, and an elastic locking element that covers the channel, is solved due to the fact that the channel is made in the form of a cylindrical pipe located at the inlet gases into the housing, and the elastic locking element is made in the form of a cap mounted on top of a cylindrical pipe; above the elastic locking element, at the gas outlet from the valve body, there is a membrane filter made of microporous hydrophobic polymer material with a pore size of 1 to 10 microns, which is fixed in the valve body by a pressure plate and covered with a lid with a central ventilation hole.

At the same time, the body of the safety valve can be located in the hole of the battery cover and provided with an external thread, and a sealing ring gasket made of rubber with a high content of silicone and rubber can be installed between the valve body and the battery, ensuring a tight connection.

In addition, the cap may be made of an elastic material resistant to the corrosive effect of the electrolyte.

Also, the design and material of the membrane filter can ensure its rupture with a sharp increase in pressure inside the battery housing, protecting the latter from destruction.

The technical result provided by the above set of essential features is to increase the reliability and safety of the battery due to:

- the geometry and material of the battery case, as well as the presence of flat stiffeners on the walls of the case, which increases its strength and eliminates ignition or fusion of the case; the honeycomb design of the case not only increases its strength properties, but also increases its heat transfer, which reduces the overheating of the case and makes it possible to operate the battery in a wider temperature range (from -25 ° С to + 50 ° С);

- the use of a valve device with the possibility of preventing electrolyte leakage, as well as with the possibility of discharge of gases generated inside the battery, which reduces the corrosion of surrounding parts, and the likelihood of destruction of the battery housing and allows you to create an efficient and easy to maintain battery;

- the presence of a hydrophobic membrane filter in the design of the safety valve, which protects the battery from moisture penetrating into the housing and thereby reduces its explosion hazard;

- the use of a nickel coating for the material of the terminals, which reduces the heating of the terminals, and also prevents their oxidation;

- the use of gaskets made of rubber with a high content of silicone and rubber, ensuring the tightness of the connection.

LIST OF DRAWINGS FIGURES

The essence of the utility model is illustrated by the drawings presented in figures 1-4.

In Fig.1 - shows a lithium-ion battery (circuit assembly structure design);

Figure 2 - shows a lithium-ion battery in the context;

Figure 3 - shows the safety valve of the lithium-ion battery assembly;

Figure 4 - shows the assembly diagram of the parts of the safety valve of the lithium-ion battery.

INFORMATION CONFIRMING THE POSSIBILITY OF IMPLEMENTING A USEFUL MODEL

The inventive device consists of a cathode and anode (not shown in the drawings) located in a sealed enclosure 1. In the openings of the cover 5, terminals 2 and 4 are connected to the anode and cathode, respectively, and a safety valve 8 is used to relieve excess internal pressure in the accumulator (FIG. .1 and 2).

The housing 1 is made in the form of a rectangular prism, at the base of which lies a rectangle. The housing 1 of the battery is made of hardened fire-resistant fiberglass, and its walls are made in the form of a honeycomb structure. The walls of the housing, corresponding to the large sides of the base, and their vertical joints have stiffeners (not shown in the drawing).

Terminals 2 and 4 and the safety valve 8 are fixed in the cover 5 with threaded connections. In this case, the terminals are attached to the battery case cover using union nuts 7. The nuts are made of aluminum-magnesium alloy and have high mechanical strength, as well as provide a well-fitted screw thread connection. Between the terminals and the cover there are installed sealing ring gaskets 3 made of rubber with a high content of silicone and rubber, ensuring the tightness of the connection.

The cathode terminal 4 is made of aluminum and / or aluminum alloy. Anode terminal 2 is made of a copper-zinc alloy. This provides higher mechanical strength compared to pure copper, as well as a well-fitting threaded joint. The material from which the terminals are made has a nickel coating.

An identification tag 6 is mounted on the battery cover 5, indicating the anode terminal. The identification round mark is used to distinguish between the cathode and anode terminals so that they are not confused during installation.

The housing of the lithium-ion battery is a honeycomb design, which increases its strength properties and heat removal from the surface of the housing, and the fire-resistant properties of the material of which the housing is made protect it from ignition. The material and design of the housing 1 provide the battery in the temperature range from -25 ° C to + 50 ° C.

The safety valve 8 of the lithium-ion battery contains a housing 10 with a channel 9 for the exit of gases from the battery and an elastic locking element 12 blocking the channel. The channel is formed by a cylindrical pipe 11 located at the gas inlet to the valve body, and the elastic locking element 12 is made in the form of a cap mounted on top of the cylindrical pipe 11 (Fig.3 and 4).

The body 10 of the safety valve 8 together with the cap controls the pressure when opening and closing the valve, in combination with the cover 5 of the battery ensures the tightness of the valve.

Above the elastic locking element 12, at the gas outlet from the valve body, there is a membrane filter 13, which is fixed in the valve body by the pressure plate 14. The pressure plate 14 serves to tightly fasten the pressure relief valve body.

On top of the membrane filter 13 is covered with a cover 15 with a central ventilation hole 16. The cover 15 of the safety valve is designed to protect the membrane filter from dust, as well as as a decorative element. The cover 15 is made of hard rubber.

The membrane filter 13 is made of a microporous hydrophobic polymer material, with a pore size of 1 to 10 microns.

The housing 10 of the safety valve 8 of the battery is located in the hole of the cover 5 of the battery and is provided with an external thread. Between the valve body 8 and the battery cover 5, a sealing ring gasket 17 is made of rubber with a high content of silicone and rubber, which ensures the tightness of the connection.

The locking element 12 of the valve, made in the form of a cap, is made of an elastic material resistant to the corrosive effect of the electrolyte.

The design and material of the membrane filter 13 ensure its rupture with a sharp increase in pressure inside the battery housing, protecting the latter from destruction.

The principle of operation of the safety valve:

The cap in its natural state hermetically closes the valve channel, preventing air from entering from the outside. When the internal pressure of the battery becomes greater than the external and reaches a certain value (pressure with the valve open 20-30 kPa), the gas overcomes the elasticity of the rubber, causes an increase in the diameter of the lower channel of the rubber cap, and is released through the open slot. When the internal pressure drops to a certain value (pressure with the valve closed 10-15 kPa), the rubber tightly seals the valve channel, and gas production stops. Then the pressure inside the battery is defined as the pressure of the closed valve of the rubber cap. Even if the pressure inside the battery is less than the external pressure (i.e. negative pressure), the rubber cap will also block the flow of air from the outside.

Due to the natural hydrophobicity of the material of which the membrane filter 13 is made, as well as due to the hole diameter of 1-10 microns, it is possible to achieve the effect of ventilation and waterproofing the battery. A pressure relief valve with a membrane filter prevents electrolyte leakage. Despite the fact that the membrane filter is thin-layer and has the properties of special mechanical strength, in the event of a short circuit or other reason that can cause a sharp increase in pressure inside the accumulator, the filter can break and cause the valve core to disconnect to release gas. This will lead to the exclusion of explosive situations.

Rugged non-flammable housing of the inventive lithium-ion battery can minimize the possibility of ignition or melting of the battery.

The new battery is designed to operate in various climatic conditions with an ambient temperature of -25 ° C to + 50 ° C and an ambient humidity of 96%.

Claims (11)

1. A lithium-ion battery containing an electrode block consisting of a cathode and anode placed in a sealed enclosure, which is a rectangular prism, at the base of which lies a rectangle, and a lid, in the openings of which are installed a safety valve designed to relieve excess internal pressure in battery, and terminals connected to the cathode and anode, characterized in that the battery case is made of hardened fire-resistant fiberglass, and its walls are made in the form of a honeycomb structure, etc. this wall, corresponding to large sides of the base, and their vertical joints are stiffening ribs, and the safety valve and the terminals are secured in the cover by means of threaded connections. 2. The lithium-ion battery according to claim 1, characterized in that the terminals are attached to the cover of the battery case with ring nuts, and sealing rings made of rubber with a high content of silicone and rubber are installed between the terminals and the cover, ensuring a tight connection. 3. The lithium-ion battery according to claim 1, characterized in that the cathode terminal is made of aluminum and / or aluminum alloy. 4. The lithium-ion battery according to claim 1, characterized in that the anode terminal is made of a copper-zinc alloy. 5. The lithium-ion battery according to claims 1, 3 and 4, characterized in that the material from which the terminals are made has a nickel coating. 6. The lithium-ion battery according to claim 1, characterized in that the material and design of the housing ensure that the battery operates in the temperature range from -25 ° C to + 50 ° C. 7. The lithium-ion battery according to claim 1, characterized in that an identification mark is installed on the battery cover indicating the anode terminal. 8. The safety valve of a lithium-ion battery, comprising a housing with a channel for the entrance of gases formed inside the battery, and an elastic shut-off element overlying the channel, characterized in that the channel is made in the form of a cylindrical nozzle located at the gas inlet to the housing, and an elastic shut-off element made in the form of a cap mounted on top of a cylindrical pipe; A membrane filter made of microporous hydrophobic polymer material with a pore size of 1 to 10 μm, which is fixed in the valve body by a pressure plate and covered with a lid with a central ventilation hole, is located above the elastic locking element, at the outlet of gases from the valve body. 9. The safety valve of claim 8, characterized in that its body is located in the hole of the battery cover and is provided with an external thread, and a sealing ring gasket made of rubber with a high content of silicone and rubber is installed between the valve body and the valve, ensuring a tight connection . 10. The safety valve of claim 8, wherein the cap is made of an elastic material resistant to the corrosive effect of the electrolyte. 11. The safety valve of claim 8, characterized in that the design and material of the membrane filter ensure its rupture with a sharp increase in pressure inside the battery housing, protecting the latter from destruction.

Images