CN220456617U - Battery cell - Google Patents

Abstract

The utility model relates to the technical field of batteries, in particular to a battery, which comprises: the electrolyte storage device comprises a shell with an inner wall, wherein the inner wall is used for limiting an inner cavity in the shell, electrolyte and at least one electric core are arranged in the inner cavity, the electric core is provided with a bending part, a gap is formed between the bending part and the inner wall, and/or a gap is formed between the bending parts of two adjacent electric cores, a liquid storage part used for storing the electrolyte is arranged in the gap, the liquid storage part has elasticity, and the electrolyte is released outwards when the liquid storage part is pressed. The liquid storage part is arranged in the gap formed by the bending part of the battery cell and the inner wall of the shell, so that the size of the shell and the size of the battery cell are not influenced by the existence of the liquid storage part, and the liquid storage part is only filled in the gap which exists originally and cannot influence the volume energy density of the battery.

Description

Battery cell

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery.

Background

Chemical power sources represented by lithium ion batteries are widely used in the field of new energy automobiles and energy storage. Consumers always want longer service lives of batteries, i.e., extra long cycle performance, from a cost standpoint. Current lithium ion batteries generally have a cycle life of around 5000 times, one of the factors limiting battery cycle life is electrolyte drying, because the electrolyte is gradually consumed during the continuous charge and discharge of the battery, and at the later stage of life, the positive electrode and the negative electrode cannot obtain enough electrolyte. However, the initial injection of excess electrolyte during the battery manufacturing process is also disadvantageous because the cells are in excess electrolyte and the excess film-forming additive continuously consumes active Li components in the battery, resulting in a significant increase in the rate of degradation of the battery, thereby affecting the service life of the battery. Therefore, it is desirable to ensure that an appropriate amount of electrolyte is contained in the battery at the initial stage of the battery and that the electrolyte can be replenished at the later stage of the life, but the difficulty of replenishing the electrolyte from the outside after the battery is packaged is very great.

For this purpose, chinese patent application No. (CN 115312890 a) discloses a battery and a method for manufacturing the same, in which an elastic liquid storage element is provided between the battery core and the casing; the elastic liquid storage element is at least arranged in the direction of thickness change of the positive electrode and the negative electrode in the battery charging and discharging process, and along with the battery charging and discharging and aging process, the elastic liquid storage unit can adjust electrolyte distribution in the battery at any time, so that the positive electrode and the negative electrode of the battery are always in a sufficient electrolyte environment, the problem of electrolyte drying is avoided, and the cycle life of the battery is prolonged.

It is noted that the above-mentioned elastic liquid storage element is located on at least one side surface of the battery cell, and the planar dimension of the elastic liquid storage element is the same as the dimension of the outermost pole piece, so that in order to install the elastic liquid storage element into the battery case, the dimension of the battery case is either increased or the dimension of the battery cell is reduced, but in any case, the volumetric energy density of the battery is reduced.

Disclosure of Invention

The utility model aims to provide a battery, which is characterized in that electrolyte is supplied to a battery cell without reducing the volume energy density.

To achieve the above object, there is provided a battery including: the electrolyte storage device comprises a shell with an inner wall, wherein the inner wall is used for limiting an inner cavity in the shell, electrolyte and at least one electric core are arranged in the inner cavity, the electric core is provided with a bending part, a gap is formed between the bending part and the inner wall, and/or a gap is formed between the bending parts of two adjacent electric cores, a liquid storage part used for storing the electrolyte is arranged in the gap, the liquid storage part has elasticity, and the electrolyte is released outwards when the liquid storage part is pressed.

In some embodiments, the battery cell is wrapped with a non-elastic film, and the liquid storage component at the bending part of the housing is arranged inside the non-elastic film.

In some embodiments, the reservoir member located between the curved portions of adjacent two of the cells is disposed outside the inelastic film.

In certain embodiments, the inelastic film is wrapped around the outside of all of the cells.

In some embodiments, the inelastic film is made of polypropylene.

In certain embodiments, the inelastic film has a thickness of 0.1 to 0.3mm.

In some embodiments, the reservoir member is internally provided with a hole for containing the electrolyte.

In certain embodiments, the reservoir component is a sponge or rubber.

In some embodiments, the cross-section of the inner cavity is rectangular, the cross-section of the curved portion is circular arc-shaped, and the cross-section of the gap is triangular-like with at least one side being the circular arc-shaped.

In certain embodiments, the reservoir member has a profile that matches the profile of the void.

Compared with the prior art, the utility model has the beneficial effects that: the liquid storage part is arranged in a gap formed by the bending part of the battery core and the inner wall of the shell, so that the size of the shell and the size of the battery core cannot be influenced by the existence of the liquid storage part, and the battery is only filled in the originally existing gap, so that the volume energy density of the battery cannot be influenced. In addition, when the battery cell expands along with the increase of the cycle times, the liquid storage part is extruded by the battery cell, so that electrolyte stored in the battery cell is released outwards, and additional electrolyte is provided for the battery cell, so that the battery cell is supplemented with the electrolyte in the later period of life. In addition, because the battery cell is gradually expanded along with the cycle times, the liquid storage part is gradually compressed, and electrolyte can be gradually released outwards, namely, the electrolyte can be correspondingly released along with the expansion of the battery cell, so that the excessive electrolyte is avoided.

Drawings

Fig. 1 is a schematic cross-sectional view of a battery having a single cell according to an embodiment of the present utility model.

Fig. 2 is a schematic diagram of the battery of fig. 1 after expansion of the cells.

Fig. 3 is a schematic cross-sectional view of a battery having two cells according to an embodiment of the present utility model.

Fig. 4 is a schematic view of the battery of fig. 3 after expansion of the cells.

In the figure: 1. a housing; 11. bending parts; 2. a battery cell; 21. a bending portion; 3. a void; 4. a liquid storage part; 5. a non-elastic film.

Detailed Description

The technical scheme of the utility model is further described below by the specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the drawings related to the present utility model are shown.

In the present utility model, directional terms such as "upper", "lower", "left", "right", "inner" and "outer" are used for convenience of understanding, and thus do not limit the scope of the present utility model unless otherwise specified.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Taking active ions in the battery as lithium ions as an example, the corresponding battery is a lithium ion battery, and the working principle of the battery is as follows: during charging, lithium ions are extracted from the crystal lattice of the positive electrode active material, pass through the electrolyte, and are intercalated into the crystal lattice of the negative electrode active material. As lithium ions are intercalated and deintercalated, the volume of the positive and negative active materials is changed. Taking a common high-nickel system as an example, in one full charge-discharge cycle, the cell volume is contracted by 5% -10% when the positive electrode is delithiated, and the cell volume is correspondingly expanded by 5% -10% when the positive electrode is intercalated with lithium; the graphite material can generate 10-20% of volume expansion in the lithium intercalation process, the volume expansion of the silicon negative electrode is up to 280%, the volume can correspondingly shrink in the lithium removal process, but some lithium has poor activity, can remain in the silicon negative electrode or form a film on the surface of particles to generate irreversible capacity loss, correspondingly, the volume of the negative electrode can not return to an initial state, and the volume expansion value can gradually increase after each discharge (negative electrode lithium removal) is finished along with the circulation, and the similar situation exists in the positive electrode. The volume change of these material layers eventually translates into volume change of the battery layers, thereby generating larger stresses inside the battery. The diaphragm is compressed when the negative electrode expands, and the electrolyte originally stored in the diaphragm is absorbed into the pole piece; on the contrary, during discharge, the positive electrode expands, the volume of the negative electrode contracts, and electrolyte in the pole piece can be released into the diaphragm. In the initial stage of battery use, electrolyte in the battery can also maintain the charge and discharge process of the battery, and as the number of times of battery use increases, the irreversible expansion of the positive electrode and the negative electrode is accumulated, so that the poor electrolyte is absorbed, the electrolyte amount stored in the diaphragm is gradually reduced, the ion transmission capacity is reduced, the temperature of the battery is increased, the side reaction is accelerated, more electrolyte is consumed, and the service life of the battery is rapidly aged.

In order to solve the above-mentioned problems, the embodiment of the present utility model provides a battery, in which a liquid storage component 4 for storing electrolyte is disposed inside the battery, and as the cycle number of the battery cell 2 increases, the battery cell 2 expands, so as to squeeze the liquid storage component 4, and release the electrolyte stored inside the liquid storage component 4 outwards, so as to provide additional electrolyte for the battery cell 2, and avoid excessive drying of the electrolyte.

Example 1

Fig. 1 shows a schematic cross-sectional view of a battery with a single cell 2 according to an embodiment of the utility model. Referring to fig. 1, the battery of the present embodiment is a prismatic battery, including: the casing 1 is a thin-walled casing part, the casing 1 is hollow and has an inner wall, the inner wall defines an inner cavity inside the casing 1, the outer shape of the inner cavity is also a rectangle, and a battery cell 2 and a certain amount of electrolyte (not shown) are arranged in the inner cavity.

As shown in fig. 1, the battery cell 2 is square, and the battery cell 2 may be formed by winding or lamination, but in any case, the battery cell 2 has a curved portion 21, and in general, the curved portion 21 is circular arc-shaped, so that the edge of the battery cell 2 and the inner wall of the housing 1 cannot be completely overlapped, and a gap 3 must be formed between the curved portion 21 and the inner wall, for example, in this embodiment, the gap 3 is formed at four bending positions 11 at the edge position of the housing 1. The cross section of the interspace 3 has substantially three edges, two of which are part of the inner wall and the other of which is part of the curvature 21, i.e. the interspace 3 can be regarded as a triangle-like shape, in this embodiment the shape of the interspace 3 is referred to as triangle-like.

As shown in fig. 1, a liquid storage member 4 is provided in the space 3, and the liquid storage member 4 is capable of absorbing the electrolyte and storing a part of the electrolyte in the inner cavity inside the liquid storage member 4. The liquid storage part 4 has elasticity and can be compressed when being subjected to external pressure, so that the electrolyte stored in the liquid storage part is released outwards. As an example of the liquid storage part 4, the liquid storage part 4 may be a sponge or a rubber having a hole therein. Since the liquid storage part 4 is arranged in the gap 3, the sizes of the shell 1 and the battery cell 2 are not affected, the size of the shell 1 is not required to be increased, and the size of the battery cell 2 is not required to be reduced, so that the volume energy density of the battery is not reduced due to the arrangement of the liquid storage part 4 in the gap 3.

As shown in fig. 1, at least one layer of inelastic film 5 is further disposed on the outer periphery of the battery cell 2, and the inelastic film 5 has no elasticity or only small elasticity and cannot be elastically deformed significantly, in this embodiment, four liquid storage parts 4 at the corners of the housing 1 are also disposed inside the inelastic film 5, so that the battery cell 2 and the liquid storage parts 4 are bound inside the inelastic film 5. As an example of the inelastic film 5, the inelastic film 5 may be made of polypropylene and has a thickness of 0.1 to 0.3mm, preferably 0.15mm.

Fig. 2 shows a schematic cross-sectional view of the cell 2 shown in fig. 1 after expansion. Referring to fig. 2, as the number of charging and discharging operations of the battery cell 2 increases, the volume of the battery cell 2 increases gradually, particularly, the dimension in the thickness direction (up-down direction in fig. 2) increases, so that the perimeter of the battery cell 2 increases, the shape of the inelastic film 5 changes correspondingly with the change of the shape of the battery cell 2, but since the inelastic film 5 cannot be elastically deformed obviously, the perimeter of the inelastic film 5 is not much different from that of the original one, the inelastic film 5 will press the liquid storage part 4 inwards, so that the liquid storage part 4 is pressed towards the direction of the battery cell 2 (the direction indicated by the arrow in fig. 2 represents the direction of the pressure), the liquid storage part 4 is elastically deformed, the electrolyte stored in the battery cell is released outwards, and the battery cell 2 can absorb the released electrolyte. Further, the amount of the electrolyte extruded in the liquid storage member 4 increases as the degree of swelling of the battery cell 2 increases, so the battery of this embodiment has an adaptive electrolyte replenishing effect.

Example 2

Fig. 3 shows a schematic cross-sectional view of a battery with two individual cells 2 according to an embodiment of the utility model. Referring to fig. 2, in the present embodiment, the dimension of the casing 1 in the thickness direction is increased compared with that of embodiment 1 to accommodate two cells 2, the shape of the cells 2 is consistent with that of embodiment 1, two cells 2 are arranged in the inner cavity of the casing 1 side by side, a gap 3 is formed between the bending portion 21 of the cell 2 and four bending portions 11 at the edge position of the casing 1, and a gap 3 is also formed between the bending portions 21 of two adjacent cells 2, the gap 3 has three sides, at least one side is an inner wall, at least one side is a part of the bending portion 21, and the other side may be an inner wall or a part of the bending portion 21. In this embodiment, the shape of the void 3 may still be referred to as a triangle-like shape. A liquid storage part 4 matched with the outline of the gap 3 can be arranged in the gap 3. The periphery of the cell 2 can be provided with an inelastic film 5, the inelastic film 5 restrains four liquid storage parts 4 positioned at the folded corners of the shell 1 inside, and the liquid storage parts 4 positioned between the two cells 2 are arranged outside the inelastic parts. The reservoir member 4 and the inelastic member remain the same as in example 1.

Fig. 4 shows a schematic cross-sectional view of the cell after expansion of the two cells 2 of fig. 3. Referring to fig. 4, as the number of charging and discharging operations of the battery cell 2 increases, the volume of the battery cell 2 increases gradually, especially, the dimension in the thickness direction (up-down direction in fig. 4) increases, so that the perimeter of the battery cell 2 increases, the shape of the inelastic film 5 changes correspondingly with the change of the shape of the battery cell 2, but since the inelastic film 5 cannot be significantly elastically deformed, the perimeter of the inelastic film 5 is not greatly different from that of the original one, the inelastic film 5 will press the liquid storage part 4 located at the four corners 11 inwards, and at the same time, the liquid storage part 4 located between the bending parts 21 of the two battery cells 2 will also press outwards, so that the liquid storage part 4 is subjected to pressure in the direction towards the battery cell 2 or away from the battery cell 2 (the direction indicated by the arrow in fig. 4 represents the direction of pressure), the liquid storage part 4 is elastically deformed, the electrolyte stored in the inside is released outwards, and the battery cell 2 can absorb the released electrolyte. Further, the amount of the electrolyte extruded in the liquid storage member 4 increases as the degree of swelling of the battery cell 2 increases, so the battery of this embodiment has an adaptive electrolyte replenishing effect.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art. The generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A battery, comprising: housing (1) with an inner wall, which defines an inner cavity in the housing (1), in which cavity electrolyte and at least one cell (2) are arranged, the cell (2) has a bending part (21), a gap (3) is formed between the bending part (21) and the inner wall, and/or a gap (3) is formed between the bending parts (21) of two adjacent cells (2), characterized in that a liquid storage part (4) for storing the electrolyte is arranged in the gap (3), the liquid storage part (4) has elasticity, and the electrolyte is released outwards when the liquid storage part (4) is pressed.

2. The battery according to claim 1, characterized in that the cell (2) is externally wrapped with a non-elastic film (5), and the liquid storage part (4) at the bending position (11) of the housing (1) is arranged inside the non-elastic film (5).

3. A battery according to claim 2, characterized in that the reservoir member (4) located between the bent portions (21) of adjacent two of the cells (2) is provided outside the inelastic film (5).

4. A battery according to claim 2 or 3, characterized in that the inelastic film (5) is wrapped outside all the cells (2).

5. A battery according to claim 2 or 3, characterized in that the material of the non-elastic film (5) is polypropylene.

6. The battery according to claim 5, characterized in that the non-elastic film (5) has a thickness of 0.1-0.3 mm.

7. A battery according to claim 1, characterized in that the reservoir part (4) is internally provided with holes for receiving the electrolyte.

8. The battery according to claim 7, characterized in that the liquid storage part (4) is a sponge or rubber.

9. The battery according to claim 1, characterized in that the cross section of the inner cavity is rectangular, the cross section of the curved portion (21) is circular arc-shaped, and the cross section of the void (3) is triangular-like with at least one side being the circular arc-shaped.

10. A battery according to claim 9, characterized in that the shape of the reservoir part (4) is adapted to the shape of the interspace (3).