CN218242213U

CN218242213U - Electricity core structure

Info

Publication number: CN218242213U
Application number: CN202123050641.2U
Authority: CN
Inventors: 宋章训; 厉强; 杨庆亨
Original assignee: Zhongxing Pylon Battery Co Ltd
Current assignee: Zhongxing Pylon Battery Co Ltd
Priority date: 2021-12-07
Filing date: 2021-12-07
Publication date: 2023-01-06
Anticipated expiration: 2031-12-07

Abstract

The utility model relates to a battery technology field discloses an electricity core structure, include: the foam can absorb electrolyte, and the porosity of the foam is 30-75%; the battery cell unit is a battery cell body or is composed of at least two parallel-connection battery cell bodies, foam cotton is bonded on the surface of a naked battery cell, and the battery cell body is a cylindrical battery cell or a square battery cell body. The utility model discloses an electricity core structure, low and the processing technology of manufacturing cost is comparatively simple, the bubble cotton of addding is the high porosity material of porosity 30% -75%, the bubble cotton can fully absorb electrolyte, make the bubble cotton can reduce the loss of electrolyte in the battery course of working, in addition, along with going on of electric core circulation, the electrolyte of absorbing in the bubble cotton is released, thereby guarantee that sufficient electrolyte has occasionally been circulated to the battery, the life of battery has been prolonged, the problem of the large tracts of land black spot diving of negative pole piece that leads to because of electrolyte exhausts has been improved.

Description

Electricity core structure

Technical Field

The utility model relates to a battery technology field especially relates to an electricity core structure.

Background

With the wide application of lithium ion batteries, the requirements for the safety performance of the lithium ion batteries are continuously improved, and the lithium ion batteries are required to have more excellent service life. The cycle life of the existing lithium ion battery rarely exceeds one ten thousand times, and in the later cycle period, the electrolyte is dried up due to the accumulation of side reactions and the continuous repair of a solid electrolyte interface film, so that the battery has a rapid capacity attenuation tendency. After the battery is dissected, the large-area black spot lithium precipitation exists in the middle position of the negative pole piece of the battery core. And selecting the battery without water jumping with the same cycle number, and replenishing the electrolyte again for testing, wherein the battery can still work normally, which shows that the main reason for water jumping of the lithium ion battery is the depletion of the electrolyte. In the prior art, the liquid retention capacity is improved by coating the diaphragm, but the processing technology of the diaphragm is complex, so that the production cost of the diaphragm is higher, and the processing cost of the lithium ion battery is improved.

In order to prolong the service life of the lithium ion battery, the prior art tries to inject some electrolyte more when injecting liquid, but when the aluminum-shell battery is subjected to negative pressure formation or the soft package battery is subjected to secondary sealing, the electrolyte can be drawn back into a pipeline from a liquid injection port or two sealed edges, and unnecessary waste is caused.

SUMMERY OF THE UTILITY MODEL

Based on the above, an object of the utility model is to provide an electricity core structure has low in production cost, long service life and simple processing technology's characteristics.

In order to achieve the purpose, the utility model adopts the following technical proposal:

a cell structure, comprising: the electrolyte can be adsorbed by the foam cotton, and the porosity of the foam cotton is between 30% and 75%; the electric core unit, the electric core unit is an electric core body or comprises two at least parallel connection's electric core body, the electric core body include naked electric core and with the utmost point ear that naked electric core electricity is connected, naked electric core is coiled or is folded by positive pole piece, negative pole piece and diaphragm and establish and form, the surface of naked electric core bonds and has the bubble is cotton, the electric core body is cylinder electric core body or square electric core body.

As a preferred scheme of the battery cell structure, the foam is wrapped and bonded on the side surface of the cylindrical battery cell body.

As a preferred scheme of the battery cell structure, the foam is bonded on at least one of the upper surface and the lower surface of at least one square battery cell body, and the square battery cell body is an aluminum-shell battery cell body or a soft-package battery cell body.

As a preferred scheme of a battery cell structure, the battery cell unit is composed of at least two square battery cell bodies, at least two square battery cell bodies are sequentially stacked and welded in parallel to form a first battery core group, and the foam cotton is bonded on at least one of two surfaces of the first battery core group along the arrangement direction of the square battery cell bodies.

As a preferred scheme of the cell structure, the cell unit is composed of at least two square cell bodies, the at least two square cell bodies are sequentially stacked and welded in parallel to form a second cell group, and at most one of the foam is arranged between every two adjacent square cell bodies.

As a preferable scheme of the cell structure, the foam is bonded to at least one of two surfaces of the second cell group along the arrangement direction of the square cell body.

As a preferable scheme of the cell structure, the thickness of the foam in the second cell group is greater than the thickness of the foam adhered on the surface of the second cell group.

As a preferable scheme of the cell structure, the thickness of the foam is between 0.5mm and 3 mm.

As a preferred scheme of the cell structure, the length of the foam is the same as that of the square cell body, and the width of the foam is the same as that of the square cell body.

As a preferred scheme of the battery cell structure, the foam is EVA foam or CR foam.

The utility model has the advantages that: the utility model discloses an electricity core structure, it is direct to bond the bubble cotton on electric core body, low in production cost and processing technology are comparatively simple, the bubble cotton of addding is the high porosity material of porosity 30% -75%, the bubble cotton can fully absorb electrolyte, make the bubble cotton of addding can reduce the loss of electrolyte in the battery course of working, additionally, along with going on of electric core circulation, the volume of electric core body expands gradually, and the volume of battery is unchangeable, the electric core body can extrude the bubble cotton, make the electrolyte of bubble cotton internal adsorption released, thereby guarantee battery circulation occasionally sufficient electrolyte, the life of battery has further been prolonged, the problem of the large tracts of land black spot diving of negative pole piece that leads to because of electrolyte exhausts has been improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

Fig. 1 is a schematic top view of a cell structure provided in an embodiment of the present invention;

fig. 2 is a schematic side view of a cell structure according to a first other embodiment of the present invention;

fig. 3 is a schematic top view of a cell structure according to a second other embodiment of the present invention;

fig. 4 is a schematic top view of a cell structure according to a third other embodiment of the present invention;

fig. 5 is a schematic side view of a cell structure according to a fourth other embodiment of the present invention;

fig. 6 is a schematic side view of a cell structure according to a fifth further embodiment of the present invention;

fig. 7 is a schematic side view of a cell structure according to a sixth further embodiment of the present invention;

fig. 8 is a schematic side view of a cell structure according to a seventh further embodiment of the present invention;

fig. 9 is a schematic top view of a battery cell structure provided in the second embodiment of the present invention;

fig. 10 is a graph of cycle period and battery capacity retention obtained when accelerated cycle performance tests were performed on the batteries of example one, example two, and comparative example one.

In the figure:

1. soaking cotton; 201. a naked battery cell; 202. a tab; 21. a square cell body; 22. cylindrical battery cell body.

Detailed Description

In order to make the technical problems, technical solutions and technical effects achieved by the present invention more clear, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments, not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example one

The utility model provides an electricity core structure, as shown in fig. 1, including bubble cotton 1 and electric core unit, bubble cotton 1 can adsorb electrolyte, the porosity of bubble cotton 1 is located between 30% -75%, electric core unit is an electric core body or comprises two at least parallel connection's electric core body, electric core body includes naked electric core 201 and the utmost point ear 202 of being connected with naked electric core 201 electricity, naked electric core 201 is by positive pole piece, negative pole piece and diaphragm are convoluteed or are folded and establish and form, the surface bonding of naked electric core 201 has bubble cotton 1, electric core body is cylinder electric core body 22 or square electric core body 21. It should be noted that, as shown in fig. 2, when the battery cell body is a cylindrical battery cell body 22, the battery cell unit includes the cylindrical battery cell body 22, and the foam 1 is wrapped and bonded on the side surface of the cylindrical battery cell body 22. When one of the cell bodies included in the cell unit is a square cell body 21, the foam 1 is bonded to one of the upper surface and the lower surface of the cell body, or bonded to both the upper surface and the lower surface as shown in fig. 3.

The electric core structure that this embodiment provided, it bonds cotton 1 of bubble on electric core body directly, low and the processing technology is comparatively simple for manufacturing cost, the cotton 1 of bubble of addding is the high porosity material of porosity 30% -75%, bubble cotton 1 can fully absorb electrolyte, make the cotton 1 of bubble of addding can reduce the loss of electrolyte in the battery course of working, in addition, going on along with electric core circulation, electric core body's volume expands gradually, and the volume of battery does not change, electric core body can extrude bubble cotton 1, make the electrolyte of bubble absorption in cotton 1 released, thereby guarantee that battery circulation has sufficient electrolyte occasionally, the life of battery has further been prolonged, the problem of the black spot diving of negative pole piece large tracts of land that leads to because of electrolyte exhausts has been improved.

In other embodiments, as shown in fig. 4 and 5, the cell unit is composed of at least two square cell bodies 21, the at least two square cell bodies 21 are sequentially stacked and welded in parallel to form a first cell group, and the foam 1 is bonded on at least one of two surfaces of the first cell group along the arrangement direction of the square cell bodies 21. Specifically, at least two square cell bodies 21 of the cell unit are welded in parallel to form a first cell group, foam 1 is bonded on one of the upper surface and the lower surface of the first cell group, that is, the foam 1 is only arranged on the surface of the first cell group, and the foam 1 is bonded to one or two square cell bodies 21 at the two ends of the first cell group.

Specifically, as shown in fig. 1, the electric core unit of this embodiment is parallelly connected by two electric core bodies and constitutes, and naked electric core 201 of electric core body is formed by positive pole piece, negative pole piece and diaphragm adoption Z style of calligraphy are folded, and electric core body is square electric core body 21, and it has bubble cotton 1 to bond between two square electric core bodies 21, and bubble cotton 1 covers on square electric core body 21's surface. Further, the square battery cell body 21 of the embodiment is a soft-package battery cell body. In other embodiments, the square battery cell body 21 may also be an aluminum-clad battery cell body, and is specifically configured according to actual needs. In other embodiments, as shown in fig. 6, the cell unit is formed by connecting two cell bodies in parallel, the foam 1 is adhered between two square cell bodies 21, and the foam 1 is adhered on one of the upper surface and the lower surface of the cell unit.

Further, the porosity of the foam 1 of the present example was 45%. In other embodiments, the porosity of the foam 1 may be other values between 30% and 75%, which can ensure the amount of the electrolyte absorbed by the foam 1 and the structural strength of the foam 1 itself, and if the porosity of the foam 1 is lower than 30%, the foam 1 is not favorable for the absorption of the electrolyte; if the porosity of the foam 1 is higher than 75%, the structural strength of the foam 1 is lower.

The thickness of the foam 1 of the present example was 1mm. In other embodiments, the thickness of the foam 1 may also be in a range of 0.5mm to 3mm, and at this time, the additional foam 1 may have sufficient liquid absorption capacity, and the volume of the cell structure may not be increased too much, so that the energy density of the finally manufactured battery is in a suitable range. In other embodiments, if the requirement on the energy density of the battery is not high, the thickness of the foam 1 may be greater than 3mm, which is specifically determined according to actual needs.

In other embodiments, as shown in fig. 7 and 8, the cell unit is composed of at least three square cell bodies 21, the at least three square cell bodies 21 are sequentially stacked and welded in parallel to form a second cell group, and at most one foam 1 is disposed between two adjacent square cell bodies 21. Specifically, when the cell unit includes three square cell bodies 21, the number of the foam 1 may be one or two, and if the number of the foam 1 is two, the foam 1 is disposed between two adjacent square cell bodies 21; if the number of bubble cotton 1 is one, be located and be equipped with between square electric core body 21 in the middle of and the square electric core body 21 and steep cotton 1, square electric core body 21 in the middle of this moment and this square electric core body 21 welding and parallel connection, and do not have between square electric core body 21 in the middle of and another square electric core body 21 to steep cotton 1, welding and parallel connection between the two. When the cell unit comprises four square cell bodies 21, the number of the foam cotton 1 in the cell structure is at most three; when the battery cell unit includes at least five square battery cell bodies 21, the maximum number of the foam cotton 1 disposed between these square battery cell bodies 21 is smaller than the number of the square battery cell bodies 21, and at most one foam cotton 1 is disposed between two adjacent square battery cell bodies 21.

In other embodiments, as shown in fig. 8, the foam 1 is adhered to at least one of two surfaces of the second cell group along the arrangement direction of the square cell bodies 21. Specifically, the foam 1 may be provided on one of two surfaces of the second cell group in the arrangement direction of the square cell body 21, or on both surfaces at the same time.

Further, because the electrolyte that square electric core body 21 that is located the second electric core group middle part consumed is more, therefore, the thickness that the cotton 1 of bubble that is located the second electric core group is greater than the thickness that bonds at the cotton 1 of bubble on second electric core group surface, make the cotton 1 of bubble in the second electric core group adsorb more electrolyte, along with the use of square electric core body 21, the electrolyte that the square electric core body 21 at middle part consumed is more, because electric core unit expands gradually, bubble cotton 1 is extrudeed and thickness reduces gradually, the electrolyte that adsorbs in bubble cotton 1 is released, the electrolyte of release is consumed at the in-process of square electric core body 21 work gradually, make the life of battery longer.

The foam 1 of this example is EVA foam. In other embodiments, the foam 1 may also be CR foam or made of other materials, and the foam 1 may be a flame retardant foam pad or a non-flame retardant foam pad, specifically selected according to actual needs.

More specifically, the capacity of the battery cell structure of this embodiment is 2.5AH, the length of the foam 1 is the same as the length of the square battery cell body 21, and is 114mm, the width of the foam 1 is the same as the length and the width of the square battery cell body 21, and is 96mm, and two square battery cell bodies 21 are welded together with the foam 1 in the middle, and are packaged in a soft package battery case, 26g of electrolyte is injected after baking, and a complete battery is obtained through processes such as formation, high-temperature aging, secondary sealing and capacity grading.

Example two

The difference between the embodiment and the embodiment is that, as shown in fig. 9, two pieces of foam 1 are further bonded on the outer surface of the battery cell unit of the embodiment, the three pieces of foam 1 have the same length, width, thickness and porosity, after the two square battery cell bodies 21 and the three pieces of foam 1 are welded together, the two square battery cell bodies are packaged in a soft package battery case, 38g of electrolyte is injected after baking, and a complete battery is obtained through the processes of formation, high-temperature aging, secondary sealing, capacity grading and the like.

Comparative examples

The square battery core bodies 21 with the same capacity are processed by the same processing technology as that of the first embodiment and the second embodiment, the two square battery core bodies 21 are directly welded and connected without foam 1, the two square battery core bodies 21 are packaged in a soft package battery, electrolyte with different masses is injected after baking, 20g of electrolyte, 26g of electrolyte and 38g of electrolyte are respectively injected, and the complete battery is obtained by the processes of formation, high-temperature aging, secondary sealing, capacity grading and the like. At this time, an example of a battery manufactured by injecting 20g of the electrolyte was defined as comparative example one, an example of a battery manufactured by injecting 26g of the electrolyte was defined as comparative example two, and an example of a battery manufactured by injecting 38g of the electrolyte was defined as comparative example three.

The batteries obtained in example one, example two, comparative example one, comparative example two and comparative example three were subjected to a first cycle test, and the experimental data obtained are shown in the following table.

As can be seen from the above table, since the injection amount of the electrolyte of the battery in the example one was the same as that of the battery in the comparative example two and the injection amount of the electrolyte of the battery in the example two was the same as that of the battery in the comparative example three, it was found that the loss amount of the electrolyte was significantly reduced after the foam 1 was increased.

From the size of the first effect of each battery obtained in the above table, the increased foam 1 and the electrolyte charged more do not reduce the first effect of the battery, that is, the redundant electrolyte in the battery does not generate more side reactions to reduce the first effect, the foam 1 can fully adsorb the electrolyte, and the electrolyte does not exist in a free state.

From the direct current internal resistance perspective, the direct current internal resistance of the battery with high liquid retention capacity is relatively small, and is reduced by about 10%. Under a larger multiplying power, the battery with high liquid retention capacity is more beneficial to the rapid migration and exchange of lithium ions.

Further, the accelerated cycle performance test was continued for the first example, the second example, and the first comparative example, the test current was 2C, the voltage interval was 2.5V to 3.6V, the test temperature was between 52 ℃ and 58 ℃, and the thickness of the cell was kept uniform at the initial cycle by a constant gap steel plate jig, resulting in the high temperature cycle curve shown in fig. 10.

As can be seen from the high-temperature accelerated circulation tendency, the circulation tendency is remarkably improved with the increase of the liquid retention amount. The average liquid retention amount of the two batteries of the first comparative example is 19.4g because no foam 1 is additionally arranged, and the corresponding accelerated cycle trend is about 360 weeks; the four batteries of the first and second embodiments all contain the foam 1, the liquid retention amount of the foam 1 is higher, and the accelerated circulation trend is also optimal, so that the battery cell structure of the first embodiment can slow down the rapid water jump of the battery in the later cycle period due to the dry-out of the electrolyte by effectively improving the liquid retention capacity of the battery cell structure, and the cycle performance of the battery is improved.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. A cell structure, comprising:

the electrolyte-absorbing foam comprises foam (1), wherein the foam (1) can absorb electrolyte, and the porosity of the foam (1) is 30-75%;

the electric core unit, the electric core unit is an electric core body or comprises two at least parallel connection's electric core body, the electric core body include naked electric core (201) and with utmost point ear (202) that naked electric core (201) electricity is connected, naked electric core (201) are coiled or are folded by positive pole piece, negative pole piece and diaphragm and establish and form, the surface bonding of naked electric core (201) has bubble cotton (1), the electric core body is cylinder electric core body (22) or square electric core body (21).

2. The cell structure of claim 1, wherein the foam (1) is wrapped and bonded to the side of the cylindrical cell body (22).

3. The cell structure of claim 1, wherein the foam (1) is bonded to at least one of an upper surface and a lower surface of at least one of the square cell bodies (21), and the square cell body (21) is an aluminum-shell cell body or a soft-package cell body.

4. The cell structure of claim 1, wherein the cell unit is composed of at least two square cell bodies (21), at least two square cell bodies (21) are sequentially stacked and welded in parallel to form a first cell group, and the foam (1) is bonded to at least one of two surfaces of the first cell group along the arrangement direction of the square cell bodies (21).

5. The cell structure of claim 1, wherein the cell unit is composed of at least two square cell bodies (21), at least two square cell bodies (21) are sequentially stacked and welded in parallel to form a second cell group, and at most one foam (1) is arranged between two adjacent square cell bodies (21).

6. The cell structure of claim 5, wherein the foam (1) is bonded to at least one of two surfaces of the second cell group along the arrangement direction of the square cell body (21).

7. The cell structure of claim 6, wherein the thickness of the foam (1) in the second cell group is greater than the thickness of the foam (1) adhered to the surface of the second cell group.

8. The cell structure of claim 6, characterized in that the thickness of the foam (1) lies between 0.5mm and 3 mm.

9. The cell structure of claim 1, wherein the length of the foam (1) is the same as the length of the square cell body (21), and the width of the foam (1) is the same as the width of the square cell body (21).

10. The cell structure of claim 1, wherein the foam (1) is an EVA foam or a CR foam.