CN214898608U - Battery stack structure and laminate polymer battery - Google Patents

Abstract

The utility model relates to a technical field of battery packing provides a battery laminated structure and laminate polymer battery, and wherein battery laminated structure includes: a battery laminate; the elastic cylindrical structure is sleeved on the battery laminated body; the first elastic layer is arranged on the upper end face of the elastic cylindrical structure and is provided with a hole; the second elastic layer is arranged on the lower end face of the elastic cylindrical structure and is provided with a pore; the soft package battery comprises the battery laminated structure; by adopting the technical scheme: the first elastic layer and the second elastic layer have elasticity, so that the internal stress of the over-expansion of the negative plate at the later cycle stage of the battery can be relieved; after the battery is filled with liquid, the first elastic layer and the second elastic layer have liquid absorption and retention properties, and the electrolyte can move to the pole pieces under the expansion stress of the negative pole pieces; the battery stack body is accommodated in the elastic cylindrical structure, so that the internal structure of the battery stack body is prevented from being misplaced, and the appearance quality of the battery is improved.

Description

Battery stack structure and laminate polymer battery

Technical Field

The utility model relates to a technical field of battery packing, more specifically say, relate to a battery stack structure and laminate polymer battery.

Background

The existing soft package battery has the following defects:

the liquid retention capacity of the soft package battery is low

The external package of laminate polymer battery uses the plastic-aluminum membrane to encapsulate, and plastic-aluminum membrane shell texture is softer. It is difficult to hold a sufficient amount of electrolyte inside a pouch battery compared to a hard-shell power battery. When the amount of electrolyte stored in the soft package battery is large, the soft package battery is soft and cannot reach the hardness required by a customer; when the electrolyte stored in the soft package battery is slightly less, the electrochemical performance of the soft package battery is weakened, and particularly the cycle performance of the battery is greatly reduced.

In the later period of recycling of the soft package battery with low liquid retention, the electrolyte between the positive and negative pole pieces is slightly less and even is dried up, and lithium ions between the positive and negative pole pieces and the diaphragm which are dried up by the electrolyte cannot be normally dissociated and conducted. In the process of charging and discharging of the battery, the lithium ions are blocked when penetrating through the diaphragm, the impedance of the battery is increased, the cycle life of the battery is further reduced, and the lithium ions cannot be dissociated to the surface of a negative electrode material for reaction in severe cases, so that lithium dendrites are generated to pierce through the diaphragm, and the safety problem of the battery is caused.

In the manufacture of pouch batteries, in order to meet the hardness requirements of batteries by customers, the liquid retention amount inside the batteries is relatively small, and thus, partial electrochemical performance of the pouch batteries is weakened.

(II) excessive extrusion of battery caused by late cycle period of soft package battery

The negative plate of the soft package battery is generally prepared by homogenizing, coating, rolling and cutting graphite and silicon materials. According to the structural characteristics of graphite and silicon materials, the thickness of the fully charged negative plate of the soft package battery has the largest rebound expansion, so that the soft package battery is thickened. Laminate polymer battery fixes and makes the battery package on the module, and at laminate polymer battery circulation later stage, laminate polymer battery can further the bodiness when being full of electricity, easily leads to the excessive inflation bodiness of battery, and then laminate polymer battery can excessively extrude, and the electrical property of excessive extruded battery will obviously descend.

(III) poor appearance of Soft-package Battery

The positive and negative pole pieces of the soft package battery are manufactured by cutting and die cutting, and active materials of the positive and negative pole pieces partially fall off in the cutting and die cutting processes of the positive and negative pole pieces. The falling material particles or dust particles from an assembly plant are assembled inside the battery during the battery packaging process. In the pre-charging formation process of the soft package battery, the impurities of the material particles can move to the surface of the battery. After the soft package battery is sealed, a plurality of salient points are formed on the surface of the battery by material particle impurities in the battery, and the surface of the battery is poor. The laminated body formed by laminating the positive and negative pole pieces and the diaphragm needs to be bonded and fixed by using a termination adhesive tape, and after the termination adhesive tape is finally sealed, the surface of the battery has an impression of the termination adhesive tape, and the appearance quality of the soft package battery is also influenced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a battery laminated structure and laminate polymer battery to laminate polymer battery who solves existence among the prior art leads to excessive extrusion behind electrical property decline, the manifold cycles because of the liquid retention volume is on the low side, and the bad technical problem of outward appearance.

In order to achieve the above object, the present invention provides a battery stack structure, including:

a battery laminate that swells toward both upper and lower ends after use;

the elastic cylindrical structure is sleeved on the battery laminated body;

the first elastic layer is arranged on the upper end face of the elastic cylindrical structure and is provided with a hole; and

and the second elastic layer is arranged on the lower end face of the elastic cylindrical structure and is provided with a pore.

By adopting the technical scheme:

first, the first elastic layer, the second elastic layer and the elastic cylindrical structure form a packaging structure located outside the battery stack, which can relieve the expansion stress of the negative electrode sheet. Specifically, in the full-charging process of the battery, the pole piece in the battery laminated body expands, the elastic cylindrical structure sleeved on the battery laminated body and the first elastic layer and the second elastic layer which are positioned on the upper end face and the lower end face of the battery laminated body can bear the expansion force of the pole piece, the first elastic layer and the second elastic layer are compressed in the thickness direction after bearing the expansion force, and the first elastic layer and the second elastic layer have internal stress for buffering the expansion of the battery cathode piece, so that the battery is effectively prevented from being excessively extruded when being fully charged;

secondly, the packaging structure has the function of preserving electrolyte for the battery. Specifically, at the later stage of the use of the battery pack, the electrolyte between the positive and negative electrode plates and the diaphragm is consumed due to several charge-discharge decompositions, so that the electrolyte in the partial contact area of the positive and negative electrode plates and the diaphragm is poor. When the battery is fully charged, the battery is further thickened, the first elastic layer and the second elastic layer are compressed, and electrolyte reserved in pores of the first elastic layer and the second elastic layer can be extruded towards the two sides of the battery laminated body. Because the electrolytes in different areas have concentration difference, the surplus electrolytes in the first elastic layer and the second elastic layer move towards the two ends of the battery stack body so as to sink between the positive and negative electrode plates, so that the electrolytes stored in the first elastic layer and the second elastic layer can be dissociated to the electrolyte-poor areas of the positive and negative electrode plates and the diaphragm at the last cycle stage of the battery, and the cycle performance of the soft package battery is improved.

And finally, the elastic tubular structure is sleeved on the battery laminated body, so that poor appearance caused by material dropping during pole piece cutting and die cutting is effectively prevented. Specifically, if dust particles fall onto the positive and negative electrode plates when the positive and negative electrode plates are cut, the surface of the battery laminate is accompanied by the dust particles when the battery laminate is prepared, so that the protrusions caused by the protrusions are covered by the first elastic layer and the second elastic layer, the protrusions of the dust particles are effectively relieved, and therefore, the protrusion points caused by the positive and negative electrode dust particles cannot be observed from the outer surface of the battery. In addition, because the battery lamination body is directly sleeved in the elastic cylindrical structure, the inner wall of the battery lamination body has a bonding effect, and the pole pieces and the diaphragms in the battery lamination body are not easy to misplace through hot-pressing compounding, so that a termination adhesive tape after the pole pieces are laminated is omitted, and the appearance quality of the battery is improved.

It should be further explained that the battery stack comprises a positive plate, a negative plate and a separator, and the positive plate, the negative plate and the separator can be stacked in a Z-type stacking manner, a winding manner or a stacking manner in which the positive plate, the negative plate and the separator are made into a unit.

In one embodiment, the shape and size of the surface of the first elastic layer in contact with the elastic cylindrical structure match the shape and size of the upper end face of the battery stack, and the shape and size of the surface of the second elastic layer in contact with the elastic cylindrical structure match the shape and size of the lower end face of the battery stack.

By adopting the technical scheme, in the laminating process of the battery laminating body, the dust particles falling on the outer surfaces of the positive and negative pole pieces cause convex points on the upper and lower end surfaces of the battery laminating body to influence the appearance of the battery, and the first elastic layer and the second elastic layer are respectively arranged on the upper and lower end surfaces of the battery laminating body; in addition, the first elastic layer is completely matched with the upper end face of the battery laminated body, so that the appearance of the battery can be further improved, and similarly, the second elastic layer is completely matched with the lower end face of the battery laminated body, so that the appearance of the battery can be further improved.

In another embodiment, the first elastic layer is in a spaced structure or a striped structure, and the second elastic layer is in a spaced structure or a striped structure.

By adopting the technical scheme, more electrolyte can be reserved in the gap of the spacing structure or the stripe structure, and meanwhile, more passages are provided for the electrolyte stored in the elastic layer when the elastic layer is extruded, so that the flow path is shortened, and the electrolyte can quickly permeate into the battery laminated body to realize electrolyte supplementation; and the arrangement of the structure reduces the material consumption for laying the first elastic layer and the second elastic layer, thereby reducing the laying cost.

In one embodiment, the first and second elastic layers are the same in shape, size and material structure.

Specifically, the first and second elastic layers include lipid materials such as polyvinyl acetate, hydroxyethyl acrylate, and ethyl methacrylate copolymers.

Through adopting above-mentioned technical scheme, when battery stack's pole piece took place the inflation, first elastic layer and second elastic layer are owing to be located battery stack's two upper and lower terminal surfaces respectively, and first elastic layer and second elastic layer receive the pressure that the inflation was applyed and take place compression deformation, and first elastic layer and second elastic layer have the same elasticity, can take place the same compression deformation under the same pressure for terminal surface atress is even about the battery.

In one embodiment, the first and second elastic layers each have a thickness of 0.5mm to 3 mm.

Through adopting above-mentioned technical scheme, first elastic layer and second elastic layer have better elasticity, and first elastic layer and second elastic layer under this scope can effectively cover the dust salient point on the battery stack simultaneously.

In one embodiment, the first and second elastic layers have a thickness with an elastic compression in the range of 0 to 30%.

Specifically, the first elastic layer and the second elastic layer can be reduced in thickness by 30% at most when being pressed under the action of pressure, namely, the thickness can be reduced to 70% of the original thickness at most.

By adopting the above technical scheme, the first elastic layer and the second elastic layer can bear a maximum deformation amount of 30%, and the mutual extrusion of the battery laminated body when the battery laminated body expands is prevented within the deformation amount range.

In one embodiment, the first and second elastic layers have a porosity of 30% to 50%.

Specifically, the first elastic layer and the second elastic layer are in an elastic solidified state, the porosity is 30-50%, the electrolyte is stored in the pores of the first elastic layer and the second elastic layer, and the adhesion force on the battery laminated body is increased.

By adopting the technical scheme, the first elastic layer and the second elastic layer with the porosity of 30-50% have better electrolyte preservation capability, have strong bonding capability and can be firmly attached to the elastic cylindrical structure.

In one embodiment, the first elastic layer, the second elastic layer and the elastic cylindrical structure are an integral molded body.

Through adopting above-mentioned technical scheme, improved structural strength and the peeling capacity between first elastic layer, second elastic layer and the elasticity tubular structure for the packaging structure that above-mentioned three formed can be located on the battery stack more closely.

In one embodiment, the elastic cylindrical structure circumferentially covers the battery stack.

Specifically, the length of the elastic cylindrical structure matches the circumference of the battery stack, and the elastic cylindrical structure covers the battery stack in the circumferential direction of the battery stack.

Finely, the shape of the cross section of the elastic cylindrical structure is a square, which matches the shape of the battery stack; the elastic tubular structure is made of polymer film with thickness of 0.2-1mm, and is solid and elastic.

By adopting the technical scheme, the inner wall of the elastic tubular structure wraps the battery laminate, so that the positive and negative pole pieces and the diaphragm of the battery laminate can be effectively placed to be dislocated, and the appearance quality of the battery is improved.

In one embodiment, the elastic cylindrical structure further comprises an adhesive layer arranged on the inner wall of the elastic cylindrical structure.

Specifically, the bonding layer comprises polyvinylidene fluoride, namely the inner wall of the elastic cylindrical structure is coated with the polyvinylidene fluoride, and the thickness of the polyvinylidene fluoride is 10-50 microns.

By adopting the technical scheme, the battery laminating body is directly accommodated in the elastic cylindrical structure, the inner wall of the elastic cylindrical structure has a bonding effect, and the positive and negative pole pieces and the diaphragm in the battery laminating body are not easy to be dislocated through hot-pressing compounding, so that a stop adhesive tape after the positive and negative pole pieces are laminated is omitted, and the appearance quality of the battery is improved.

Another object of the present invention is to provide a laminate polymer battery, which comprises a housing, an electrolyte and the above-mentioned battery laminate structure, wherein the electrolyte and the battery laminate structure are accommodated in the housing.

Specifically, the manufacturing process of the pouch battery includes, but is not limited to: and placing the battery laminated body in a packaging structure, and thermally compounding the battery laminated body and the packaging structure by hot pressing the left side surface, the right side surface, the upper end surface and the lower end surface of the packaging structure at 80-90 ℃, 0.2-0.6Mpa and 30-60 s. And then packaging the compounded battery laminate structure into a shell such as an aluminum plastic film, injecting liquid, forming to prepare a soft package battery, and assembling the soft package battery into a module battery pack for charging.

By adopting the technical scheme:

first, the first elastic layer, the second elastic layer and the elastic cylindrical structure form a packaging structure located outside the battery stack, which can relieve the expansion stress of the negative electrode sheet. Specifically, in the full-charging process of the battery, the pole piece in the battery laminated body expands, the elastic cylindrical structure sleeved on the battery laminated body and the first elastic layer and the second elastic layer which are positioned on the upper end face and the lower end face of the battery laminated body can bear the expansion force of the pole piece, the first elastic layer and the second elastic layer are compressed in the thickness direction after bearing the expansion force, and the first elastic layer and the second elastic layer have internal stress for buffering the expansion of the battery cathode piece, so that the battery is effectively prevented from being excessively extruded when being fully charged;

secondly, the packaging structure has the function of preserving electrolyte for the battery. Specifically, at the later stage of the use of the battery pack, the electrolyte between the positive and negative electrode plates and the diaphragm is consumed due to several charge-discharge decompositions, so that the electrolyte in the partial contact area of the positive and negative electrode plates and the diaphragm is poor. When the battery is fully charged, the battery is further thickened, the first elastic layer and the second elastic layer are compressed, and electrolyte reserved in pores of the first elastic layer and the second elastic layer can be extruded towards the two sides of the battery laminated body. Because different areas of the electrolyte have concentration differences, the surplus electrolyte in the first elastic layer and the second elastic layer can move to the laminated positive and negative pole pieces through two ends of the battery stack body, so at the end of the battery cycle, the electrolyte stored in the first elastic layer and the second elastic layer can be dissociated to the electrolyte lean areas of the positive and negative pole pieces and the diaphragm, and the cycle performance of the soft package battery is improved.

And finally, the elastic tubular structure is sleeved on the battery laminated body, so that poor appearance caused by material dropping during pole piece cutting and die cutting is effectively prevented. Specifically, if dust particles fall on the laminated body when the positive and negative electrode plates are cut, the protrusions caused by the dust particles are covered by the first elastic layer and the second elastic layer, so that the protrusions of the dust particles are effectively relieved, and the protrusion points caused by the positive and negative electrode dust particles cannot be observed from the outer surface of the battery. In addition, because the battery lamination body is directly sleeved in the elastic cylindrical structure, the inner wall of the battery lamination body has a bonding effect, and the pole pieces and the diaphragms in the battery lamination body are not easy to misplace through hot-pressing compounding, so that a termination adhesive tape after the pole pieces are laminated is omitted, and the appearance quality of the battery is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments 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 it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a perspective view of a battery stack structure according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of a battery stack structure provided by an embodiment of the present invention;

fig. 3 is a schematic force diagram of a battery stack structure according to an embodiment of the present invention;

fig. 4 is a schematic view illustrating the flow direction of electrolyte in a battery stack structure according to an embodiment of the present invention;

FIG. 5 is a prior art schematic representation of a cell stack secured with a termination tape;

fig. 6 is a battery cycle performance diagram of an embodiment of the battery stack structure provided by an embodiment of the present invention after being assembled into a pouch battery;

fig. 7 is a graph of battery cycle performance of a comparative example after assembly into a pouch battery using a termination tape to secure a battery laminate according to the prior art.

The figures are numbered:

100-cell stack structure;

1-a battery stack;

2-an elastic cylindrical structure;

3-a first elastic layer;

4-a second elastic layer;

5-a tie layer;

6-stop the tape.

Detailed Description

In order to make the technical problem, technical solution and advantageous effects to be solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected or indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention, and are not intended to indicate that a device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or as indicating a number of technical features. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise. The following describes the specific implementation of the present invention in more detail with reference to specific embodiments:

as shown in fig. 1 to fig. 2, an embodiment of the present invention provides a battery stack structure 100, including: a battery laminate 1, an elastic tubular structure 2, a first elastic layer 3, and a second elastic layer 4. The battery laminate 1 expands towards the upper end and the lower end after use, and the elastic tubular structure 2 is sleeved on the battery laminate 1; the first elastic layer 3 is arranged on the upper end face of the elastic cylindrical structure 2, and the first elastic layer 3 is provided with pores; the second elastic layer 4 is arranged on the lower end face of the elastic cylindrical structure 2, and the second elastic layer 4 is provided with pores.

Referring to fig. 3 to 5, by adopting the above technical solution:

first, the first elastic layer 3, the second elastic layer 4 and the elastic cylindrical structure 2 form a packaging structure located outside the battery laminate 1, which can relieve the negative electrode sheet expansion stress. Specifically, (as shown in fig. 3, fig. 3 is a schematic force diagram of a packaging structure, and F is an extrusion force when the battery is fully charged) in the full charge process of the battery, the pole piece in the battery stack 1 expands, the elastic tubular structure 2 sleeved on the battery stack 1 and the first elastic layer 3 and the second elastic layer 4 located on the upper end surface and the lower end surface of the battery stack 1 will be subjected to a pole piece expansion force, the first elastic layer 3 and the second elastic layer 4 are compressed in the thickness direction after being subjected to the expansion force, and the first elastic layer 3 and the second elastic layer 4 have an internal stress for buffering the expansion of the battery pole piece, so that the battery is effectively prevented from being excessively extruded when the battery is fully charged.

Secondly, the packaging structure has the function of preserving electrolyte for the battery. Specifically, at the later stage of the use of the battery pack, the electrolyte between the positive and negative electrode plates and the diaphragm is consumed due to several charge-discharge decompositions, so that the electrolyte in the partial contact area of the positive and negative electrode plates and the diaphragm is poor. When the battery is fully charged and the battery is further thickened, the first elastic layer 3 and the second elastic layer 4 are compressed, and the electrolyte remaining in the pores of the first elastic layer 3 and the second elastic layer 4 is extruded towards the two sides of the battery stack 1. Because the electrolyte in different areas has concentration difference, the surplus electrolyte in the first elastic layer 3 and the second elastic layer 4 will move towards the two ends of the battery laminate 1, so as to permeate between the positive and negative pole pieces, and the moving direction of the electrolyte is as shown in fig. 4 (fig. 4 is a schematic diagram of the flow direction of the extruded electrolyte when the battery is fully charged in a packaging structure, and E represents the electrolyte), so at the end of the battery cycle, the electrolyte stored in the first elastic layer 3 and the second elastic layer 4 can be dissociated to the electrolyte-poor areas of the positive and negative pole pieces and the diaphragm, and the cycle performance of the soft package battery is improved.

And finally, the elastic tubular structure 2 is sleeved on the battery laminated body 1, so that poor appearance caused by material dropping during pole piece slitting and die cutting is effectively prevented. Specifically, if dust particles fall onto the positive and negative electrode plates when the positive and negative electrode plates are cut, the surface of the battery laminate 1 is accompanied by the dust particles when prepared, so that the protrusions caused by the protrusions are covered by the first elastic layer 3 and the second elastic layer 4, and therefore the protrusions of the dust particles can be effectively relieved by the design, and the protrusion points caused by the positive and negative dust particles cannot be observed from the outer surface of the battery. In addition, because the battery laminated body 1 is directly placed in the elastic cylindrical structure 2, the dislocation of the pole pieces and the diaphragm in the battery laminated body 1 is not easy to occur, and a termination adhesive tape 6 (shown in figure 5) for fixing and forming the battery laminated body 1 after the pole pieces are laminated is omitted, thereby improving the appearance quality of the battery.

It should be further explained that the battery stack 1 includes a positive electrode sheet, a negative electrode sheet, and a separator, and the positive electrode sheet, the negative electrode sheet, and the separator may be stacked in a Z-type stacking manner, a winding manner, or a stacking manner in which the positive electrode sheet, the negative electrode sheet, and the separator are made into one unit.

In one embodiment, the shape and size of the surface of the first elastic layer 3 in contact with the elastic cylindrical structure 2 matches the shape and size of the upper end face of the battery stack 1, and the shape and size of the surface of the second elastic layer 4 in contact with the elastic cylindrical structure 2 matches the shape and size of the lower end face of the battery stack 1.

By adopting the technical scheme, in the process of laminating the battery laminated body 1, the dust particles falling on the outer surfaces of the positive and negative pole pieces cause convex points on the upper and lower end surfaces of the battery laminated body 1 to influence the appearance of the battery, and the first elastic layer 3 and the second elastic layer 4 are respectively arranged on the upper and lower end surfaces of the battery laminated body 1, so that the first elastic layer 3 and the second elastic layer 4 have elasticity, the bulge caused by the dust particles can be effectively relieved, the convex points can not be observed from the outer surface of the battery, and the attractiveness of the battery is improved; in addition, the first elastic layer 3 completely fits the upper end surface of the cell laminate 1, and the appearance of the cell can be further improved, and similarly, the second elastic layer 4 completely fits the lower end surface of the cell laminate 1, and the appearance of the cell can be further improved.

In one embodiment, the first elastic layer 3 and the second elastic layer 4 are the same in shape, size, and material structure.

In another embodiment, the first elastic layer 3 is a spacer structure or a stripe structure, and the second elastic layer 4 is a spacer structure or a stripe structure.

By adopting the technical scheme, more electrolyte can be reserved in the gap of the spacing structure or the stripe structure, and meanwhile, more passages are provided for the electrolyte stored in the elastic layer when the elastic layer is extruded, so that the flow path is shortened, and the electrolyte can quickly permeate into the battery laminated body to realize electrolyte supplementation; and the arrangement of the structure reduces the material consumption for laying the first elastic layer 3 and the second elastic layer 4, thereby reducing the laying cost.

Specifically, the first elastic layer 3 and the second elastic layer 4 include lipid substances such as polyvinyl acetate, hydroxyethyl acrylate, and ethyl methacrylate copolymers.

Through adopting above-mentioned technical scheme, when battery stack 1's pole piece took place the inflation, first elastic layer 3 and second elastic layer 4 because be located battery stack 1 two upper and lower terminal surfaces respectively, and first elastic layer 3 and second elastic layer 4 receive the inflation pressure of applying and take place compression deformation, and first elastic layer 3 and second elastic layer 4 have the same elasticity, can take place the same compression deformation under the same pressure for terminal surface atress is even about the battery.

In one embodiment, the first elastic layer 3 and the second elastic layer 4 are each 0.5mm to 3mm thick.

By adopting the technical scheme, the first elastic layer 3 and the second elastic layer 4 have better elasticity, and meanwhile, the first elastic layer 3 and the second elastic layer 4 in the range can effectively cover dust protruding points on the battery laminated body 1.

In one embodiment, the first elastic layer 3 and the second elastic layer 4 have a thickness with an elastic compression in the range of 0 to 30%.

Specifically, the first elastic layer 3 and the second elastic layer 4 can be reduced in thickness by 30% at the maximum, i.e., the thickness can be reduced to 70% of the original thickness, when being subjected to a compressive force.

By adopting the above technical solution, the first elastic layer 3 and the second elastic layer 4 can withstand a deformation amount of 30% at maximum, and the cell laminate 1 is prevented from being pressed against each other when inflated within the range of the deformation amount.

In one embodiment, the first elastic layer 3 and the second elastic layer 4 have a porosity of 30% to 50%.

Specifically, the first elastic layer 3 and the second elastic layer 4 are in an elastic solidified state, have a porosity of 30-50%, have a function of preserving the electrolyte and have a certain adhesiveness, and the electrolyte is stored in the pores of the first elastic layer 3 and the second elastic layer 4, while increasing the adhesive force on the battery stack 1.

By adopting the technical scheme, the first elastic layer 3 and the second elastic layer 4 with the porosity of 30-50% have better electrolyte preservation capability and strong bonding capability, and can be firmly attached to the elastic cylindrical structure 2.

In one embodiment, the first elastic layer 3, the second elastic layer 4 and the elastic tubular structure 2 are an integral molded body.

Through adopting above-mentioned technical scheme, improved the structural strength and the peeling capacity between first elastic layer 3, second elastic layer 4 and the elasticity tubular structure 2 for the packaging structure that above-mentioned three formed can be located on the battery stack 1 more closely.

In one embodiment, the elastic cylindrical structure 2 circumferentially covers the battery stack 1.

Specifically, the length of the elastic cylindrical structure 2 matches the circumferential length of the cell laminate 1, and the elastic cylindrical structure 2 is overlaid on the cell laminate 1 in the circumferential direction of the cell laminate 1.

Finely, the shape of the cross section of the elastic cylindrical structure 2 is a square, which matches the shape of the battery laminate 1; the elastic tubular structure 2 is made of a polymer film having a thickness of 0.2 to 1mm, is solid, and has elasticity.

By adopting the technical scheme, the inner wall of the elastic tubular structure 2 wraps the battery stack body 1, so that the positive and negative pole pieces and the diaphragm of the battery stack body 1 can be effectively prevented from being dislocated, and the appearance quality of the battery is improved.

In one embodiment, an adhesive layer 5 is further included on the inner wall of the elastic cylindrical structure 2.

Specifically, the bonding layer 5 comprises polyvinylidene fluoride, namely the inner wall of the elastic cylindrical structure 2 is coated with the polyvinylidene fluoride, and the thickness of the polyvinylidene fluoride is 10-50 μm.

By adopting the technical scheme, the battery stack body 1 is directly accommodated in the elastic cylindrical structure 2, the inner wall of the elastic cylindrical structure 2 has a bonding effect, and the positive and negative pole pieces and the diaphragm in the battery stack body 1 are not easy to be dislocated through hot-pressing compounding, so that the stop adhesive tape 6 after the positive and negative pole pieces are stacked is omitted, and the appearance quality of the battery is improved.

The present embodiment also provides a pouch battery, which includes a case, an electrolyte, and the above battery laminate structure 100, where the electrolyte and the battery laminate structure 100 are accommodated in the case.

Specifically, the manufacturing process of the pouch battery includes, but is not limited to: the battery laminate 1 is placed in a packaging structure, and the left and right side faces and the upper and lower end faces of the packaging structure are subjected to hot pressing at 80-90 ℃ under 0.2-0.6Mpa for 30-60 seconds, so that the battery laminate 1 and the packaging structure are thermally laminated together. And then packaging the compounded battery laminate structure 100 into a shell such as an aluminum plastic film, injecting liquid, forming to prepare a soft package battery, and assembling the soft package battery into a module battery pack for charging.

The cell cycling functions of the present example and comparative example were compared as follows:

in the embodiment and the comparative example, the battery laminate 1 is manufactured by using the same design parameters of the positive and negative electrode materials, the coating amount, the compaction density and the like of the lithium battery and the same process flow, and after the battery laminate 1 is assembled, the battery laminate 1 is sleeved in the elastic cylindrical structure 2, as shown in fig. 2; while the comparative example directly used a conventional termination tape 6 to bond the cell stack 1, as in fig. 5.

The examples and comparative examples were made into 56Ah energy type laminated cells of size 12 × 102 × 315mm, and the cycle performance at room temperature of 25 ℃ was compared as shown in fig. 6 and 7, from which it can be seen that:

the first elastic layer and the second elastic layer on the upper end face and the lower end face of the embodiment have liquid absorbing and retaining functions and elasticity, the circulation capacity retention rate of the battery of the comparative example (shown in figure 6) is basically close to that of the battery of the embodiment (shown in figure 7) in the first 600 weeks, and the electrolyte retaining amount of the electrolyte is sufficient after the battery of the embodiment is circulated for 600 weeks, so that the electrolyte between the pole pieces can be in full contact, and the normal-temperature circulation performance of the battery of the embodiment is better than that of the comparative example.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. A battery stack structure, comprising:

a battery laminate that swells toward both upper and lower ends after use;

the elastic cylindrical structure is sleeved on the battery laminated body;

the first elastic layer is arranged on the upper end face of the elastic cylindrical structure and is provided with a hole; and

and the second elastic layer is arranged on the lower end face of the elastic cylindrical structure and is provided with a pore.

2. The battery stack structure of claim 1, wherein the shape and size of the interfacing surface of the first elastic layer and the elastic cylindrical structure match the shape and size of the upper end face of the battery stack, and the shape and size of the interfacing surface of the second elastic layer and the elastic cylindrical structure match the shape and size of the lower end face of the battery stack;

or, the first elastic layer is of a spacing structure or a stripe structure, and the second elastic layer is of a spacing structure or a stripe structure.

3. The battery stack structure of claim 1, wherein the first elastic layer and the second elastic layer are the same shape, size, and material structure.

4. The battery stack structure of claim 1, wherein the first elastic layer and the second elastic layer each have a thickness of 0.5mm to 3 mm.

5. The battery stack structure of claim 1, wherein the first elastic layer and the second elastic layer have a thickness with an elastic compression in the range of 0 to 30%.

6. The battery stack structure of claim 4, wherein the first elastic layer and the second elastic layer have a porosity of 30% to 50%.

7. The battery stack structure of claim 1, wherein the first elastic layer, the second elastic layer, and the elastic cylindrical structure are integrally formed.

8. The battery stack structure of claim 1, wherein the elastic cylindrical structure circumferentially covers the battery stack.

9. The battery stack structure of any of claims 1-8, further comprising an adhesive layer disposed on an inner wall of the elastic tubular structure.

10. A pouch cell comprising a housing, an electrolyte and the cell stack structure of any of claims 1-9, said electrolyte and said cell stack structure being contained within said housing.

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