CN219303740U - Battery monomer, battery and power consumption device - Google Patents

Abstract

The application discloses a battery monomer, a battery (1) and an electric device. The battery cell includes an electrode assembly (10). The electrode assembly (10) comprises a positive electrode plate (11), a negative electrode plate (12), a diaphragm (13), an insulating layer (14) and a glue layer (15). The positive electrode sheet (11), the separator (13) and the negative electrode sheet (12) are laminated and wound, and the electrode assembly (10) has a bending region (17). At least a part of the insulating layer (14) and at least a part of the adhesive layer (15) are arranged in the bending area (17), and the insulating layer (14) is adhered to the positive electrode pole piece (11) or the negative electrode pole piece (12) through the adhesive layer (15). In the thickness direction of the insulating layer (14), the projected area of the adhesive layer (15) is smaller than the projected area of the insulating layer (14). Based on the structure, the service life of the battery monomer can be prolonged, and the safety of the battery monomer can be improved.

Description

Battery monomer, battery and power consumption device

Technical Field

The application relates to the technical field of batteries, in particular to a battery monomer, a battery and an electricity utilization device.

Background

The electrode assembly is a component in which electrochemical reactions occur in the battery cells. The electrode assembly includes a positive electrode tab, a negative electrode tab, and a separator separating the positive electrode tab and the negative electrode tab. The positive electrode sheet, the separator and the negative electrode sheet may be wound to form a rolled electrode assembly such that the electrode assembly has a body region and a bent region disposed at an end side of the body region. However, during the use of the battery cell, metal is easily precipitated in the bent region of the electrode assembly, dendrites are easily grown in the bent region over time, and the dendrites easily cause internal short circuits of the battery cell, affecting the safety of the battery cell.

Disclosure of Invention

The embodiment of the application provides a battery monomer, battery and power consumption device to solve in the battery monomer use period, electrode assembly is at the easy dendrite that grows of zone of buckling, causes the battery monomer internal short circuit, influences the problem of battery monomer security.

The technical scheme adopted by the embodiment of the application is as follows:

in a first aspect, a battery cell is provided, the battery cell including at least one electrode assembly including a positive electrode sheet, a negative electrode sheet, a separator, an insulating layer, and a glue layer;

the positive pole piece, the diaphragm and the negative pole piece are laminated and wound, and the electrode assembly is provided with a bending area;

at least one part of the insulating layer and at least one part of the adhesive layer are arranged in the bending area, and the insulating layer is adhered to the positive pole piece or the negative pole piece through the adhesive layer; in the thickness direction of the insulating layer, the projected area of the adhesive layer is smaller than the projected area of the insulating layer.

The battery monomer that this embodiment provided, accessible glue film is firm, reliably bonds the insulating layer to the bight of arbitrary circle positive pole piece or negative pole piece for the insulating layer can be lasting, reliably stabilize in the district of buckling during battery monomer uses, can effectively reduce the insulating layer and take place the risk of shifting, coming off, thereby can ensure that the insulating layer can last lasting, stable, reliably exert utility in specific position during battery monomer uses. And the projected area of the adhesive layer in the thickness direction of the insulating layer is smaller than that of the insulating layer in the thickness direction of the insulating layer, so that the negative influence of the adhesive layer on the extensibility and deformation performance of the insulating layer is effectively reduced during the winding and prepressing forming of the electrode assembly and the use of the battery monomer, the insulating layer can be conveniently and adaptively extended and deformed along with the pole piece, the insulating layer can be conveniently and durably and reliably exerted during the use of the battery monomer, the risk of tearing defect of the insulating layer during the use of the battery monomer can be effectively reduced, and the service life of the insulating layer can be correspondingly ensured and prolonged.

The battery monomer that this application embodiment provided, still can be in electrode assembly coiling and pre-compaction shaping period and in battery monomer use period, through locating the insulating layer in the district of buckling, the bending stress that the portion of buckling born to the pole piece forms buffering utility to can effectively reduce the risk that the tearing defect leads to the active material to reduce appears in the portion of buckling of pole piece, can effectively reduce electrode assembly's the district of buckling and aggravate the risk of separating out the metal phenomenon because of the active material reduces, can effectively alleviate dendrite's growth rate, thereby can correspondingly prolong battery monomer's life, can correspondingly promote battery monomer's security. And even if dendrite grows along with the extension of the service time, the insulating layer with insulating property can also form insulating obstruction to dendrite growing towards the dendrite, can prevent dendrite from directly contacting and conducting the positive pole piece and the negative pole piece, can even obstruct and delay the growth of dendrite, thereby effectively delaying the occurrence of the phenomenon that dendrite directly causes internal short circuit of a battery monomer, effectively delaying the occurrence of the phenomenon that dendrite heats and melts off the diaphragm at the periphery of dendrite due to short circuit, causing the phenomenon that the part of the positive pole piece and the part of the negative pole piece at the part where the diaphragm is melted off directly contact the short circuit, correspondingly prolonging the service life of the battery monomer and correspondingly improving the safety of the battery monomer.

In some embodiments, the adhesive layer includes a plurality of colloids, at least a portion of which are distributed in an edge region of the insulating layer.

Through adopting above-mentioned scheme, accessible a plurality of colloids, especially through the colloid that sets up near the border of insulating layer, realize the border firm, the reliable bonding of insulating layer especially insulating layer to the kink of arbitrary circle positive pole piece or negative pole piece to can make the insulating layer can lasting, reliably stabilize the position and exert the utility. And on the basis of ensuring the fastening effect of the adhesive layer on the insulating layer, the adhesive layer is beneficial to reducing the setting quantity and occupied area of the adhesive layer, so that the negative influence of the adhesive layer on the extensibility and deformability of the insulating layer can be effectively reduced, the insulating layer can be conveniently and adaptively extended and deformed along with the pole piece, and the effect and the service life of the insulating layer can be guaranteed.

In some embodiments, the colloid is a strip-shaped colloid, and the plurality of colloids are arranged at intervals along the width direction of the insulating layer, or the plurality of colloids are arranged at intervals along the length direction of the insulating layer.

Through adopting above-mentioned scheme, can make a plurality of colloids optimize the overall arrangement in one side of insulating layer, especially make two colloids that the distance is farthest can be close to the both sides border of insulating layer respectively and set up. On the one hand, the strip-shaped adhesive can be ensured to firmly and reliably adhere the insulating layer, particularly the two side edges of the insulating layer, to the bending parts of any ring of pole pieces, so that the insulating layer can permanently and reliably stabilize the position and exert the effect. On the one hand, the arrangement quantity and occupied area of the colloid can be effectively reduced on the basis of optimizing the arrangement of each strip colloid so as to ensure the fastening effect on the insulating layer, so that the negative influence of the adhesive layer on the extensibility and deformability of the insulating layer can be effectively reduced, the insulating layer can be conveniently and adaptively extended and deformed along with the pole piece, and the effect and the service life of the insulating layer can be ensured. On the one hand, the insulating layer can be extended and deformed along with the pole piece in a period that the insulating layer is adapted to be extended and deformed along with the pole piece, so that the spacing and the extension and the deformation of the plurality of strip-shaped adhesives can be adapted to be pulled along with the insulating layer, and the adhesive layer can be ensured to exert the fastening effect on the insulating layer permanently and reliably.

In some embodiments, the gel is a bulk gel, at least a portion of which is disposed at each corner of the insulating layer.

Through adopting above-mentioned scheme, accessible a plurality of cubic colloids, especially through the cubic colloid that distributes in each bight of insulating layer, realize the bight and the border of insulating layer especially insulating layer, firmly, reliably bond to the kink of arbitrary circle pole piece to can make the insulating layer can lasting, reliably stabilize the position and exert the utility. And, because the colloid is cubic, and a plurality of cubic colloid can optimize the overall arrangement in one side of insulating layer to can do benefit to on the basis of guaranteeing the fastening utility of glue film to the insulating layer, effectively reduce the setting quantity and the occupation area of colloid, thereby can effectively reduce the glue film to the extending property of insulating layer and the negative influence of deformation performance, thereby can be convenient for the insulating layer to take place to extend, warp along with the pole piece adaptation, can do benefit to the utility and the life of guarantee insulating layer. And in the period that the insulating layer adaptively extends along with the pole piece and deforms, the plurality of block-shaped colloids can adaptively pull the distance along with the insulating layer, so that the fastening effect of the whole adhesive layer on the insulating layer can be ensured to be durable and effective.

In some embodiments, the glue layer is an electrolyte resistant hot melt glue.

By adopting the scheme, the adhesive layer can be formed by the hot melt adhesive with the characteristics of rapid adhesion, firm adhesion, stable performance and the like, so that the insulating layer can be conveniently, rapidly and reliably adhered to the bending part of the pole piece firmly. And based on the electrolyte resistance of the hot melt adhesive, the adhesive layer can exert lasting and effective fastening effect on the insulating layer during the use of the battery monomer.

In some embodiments, the ratio of the projected area of the glue layer to the projected area of the insulating layer is 20% to 50% in the thickness direction of the insulating layer.

Through adopting above-mentioned scheme, during electrode assembly coiling and pre-compaction shaping and during battery monomer use, can effectively reduce the area ratio of glue film for the insulating layer on the basis of guaranteeing the fastening utility of glue film to the insulating layer to can effectively reduce the negative effect of glue film to the extensibility and the deformability of insulating layer, thereby can be convenient for the insulating layer take place to extend, warp along with the pole piece adaptation, can be convenient for the insulating layer lasting, the reliable performance utility of battery monomer during use, can effectively reduce the risk that the insulating layer appears tearing the defect during battery monomer use, can effectively ensure and prolong the life of insulating layer.

In some embodiments, the thickness of the glue layer is 2 micrometers (um) to 8um.

Through adopting above-mentioned scheme, can effectively attenuate the thickness of glue film on the basis of the fastening utility of glue film to the insulating layer to can be favorable to guaranteeing and improve electrode assembly and single energy density of battery.

In some embodiments, at least one insulating layer is bonded to the inside of the inner-most positive pole piece by a glue layer in the inflection region.

Through adopting above-mentioned scheme, on the one hand, can produce the metal that separates out at the bight of the negative pole piece of inner race, and during follow the extension of time, grow dendrite from the defect of bight of diaphragm, through setting up the insulating layer of the bight inboard of positive pole piece of inner race, insulating separation is carried out to the dendrite that grows, with prevent dendrite direct contact switch-on positive pole piece and negative pole piece, thereby can be in the phenomenon emergence of the direct internal short circuit that causes of battery monomer of metal that produces easily of inner race of dendrite and the negative pole piece of inner race, effectively delay "dendrite and melt the diaphragm of dendrite week side because of the short circuit, cause the phenomenon emergence of the positive pole piece part and the direct contact short circuit of negative pole piece part of diaphragm melt-off, thereby can correspondingly lengthen the life of battery monomer, can correspondingly promote the security of battery monomer.

On the other hand, the extrusion stress born by the bending part of the positive electrode plate of the innermost ring can be buffered through the insulating layer arranged on the inner side of the bending part of the positive electrode plate of the innermost ring during the winding and prepressing forming of the electrode assembly and during the use of the battery cell, so that the risk of active substance reduction caused by tearing defect of the bending part of the positive electrode plate of the innermost ring is reduced; even the tensile stress born by the bending part of the cathode pole piece at the innermost ring can be buffered, so that the risk of active substances reduction caused by tearing defects at the bending part of the cathode pole piece at the innermost ring is reduced. Therefore, the risk of metal precipitation caused by reduction of active substances can be effectively reduced, the growth rate of dendrites between the anode pole piece at the innermost ring and the cathode pole piece at the innermost ring can be effectively relieved, the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

In some embodiments, at least one insulating layer is bonded to the outside of the inner-most positive pole piece by a glue layer in the inflection region.

By adopting the scheme, the tensile stress born by the bending part of the positive electrode plate of the innermost ring is buffered through the insulating layer arranged on the outer side of the bending part of the positive electrode plate of the innermost ring during the winding and prepressing forming of the electrode assembly and the use of the battery cell, so that the risk of active material reduction caused by tearing defect of the bending part of the positive electrode plate of the innermost ring is reduced; and even the extrusion stress born by the bending part of the negative electrode plate of the secondary inner ring can be buffered, so that the risk of active substances reduction caused by tearing defects of the bending part of the negative electrode plate of the secondary inner ring is reduced. Therefore, the risk of metal precipitation caused by reduction of active substances can be effectively reduced, the growth rate of dendrites between the positive pole piece of the innermost ring and the negative pole piece of the secondary inner ring can be effectively relieved, the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

Through adopting above-mentioned scheme, still can be in battery monomer use period, through the insulating layer that sets up the bight outside of the anodal pole piece of inner circle, carry out insulating separation to the dendrite that grows towards it to prevent dendrite direct contact to switch on the anodal pole piece of inner circle and the negative pole piece of secondary inner circle. Therefore, the phenomenon that dendrites directly cause internal short circuit of the battery monomer can be effectively delayed between the positive pole piece of the innermost ring and the negative pole piece of the secondary inner ring, the phenomenon that dendrites melt the diaphragm at the periphery of the dendrites due to short circuit, and the phenomenon that the positive pole piece part and the negative pole piece part at the part where the diaphragm is melted are directly contacted with the short circuit can be effectively delayed, so that the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

In some embodiments, the bending region is provided with two insulating layers, wherein one insulating layer is adhered to the inner side of the positive pole piece at the innermost ring through a glue layer, and the other insulating layer is adhered to the outer side of the positive pole piece at the innermost ring through a glue layer.

Through adopting above-mentioned scheme, the district accessible two insulating layers of buckling, the metal is precipitated easily, the metal condition is precipitated relatively serious "between the positive pole piece of inner circle and the negative pole piece of inner circle" and "between the positive pole piece of inner circle and the negative pole piece of secondary inner circle" effectively delays short circuit risk to bear bending stress great, the bending part department of the positive pole piece of inner circle that easily appears tearing the defect effectively alleviates extrusion stress and tensile stress, realizes reducing bending tearing risk, thereby can effectively prolong the free life of battery, can effectively promote the free security of battery. By adopting the scheme, the number of the insulating layers can be reduced while the effectiveness of the insulating layers is maximized, so that the energy density of the electrode assembly and the battery cells is ensured and improved.

In some embodiments, the electrode assembly has a body region and a inflection region disposed at an end side of the body region; the insulating layer is provided with a bending section which is bent and arranged in the bending area, and an extension section which is connected with the end part of the bending section and is arranged in the main body area.

By adopting the scheme, the setting area of the insulating layer can be correspondingly prolonged, and the preset position of the insulating layer on the continuous positive pole piece or the continuous negative pole piece is provided with a wider fault tolerance range, so that the insulating layer can be effectively ensured to be clamped at a bending section between the bending part of the pole piece and the diaphragm when the electrode assembly is wound and formed, and the extending section which can be adaptively extended to the main body area according to the position fault tolerance can be effectively reduced, and the precision requirement on the preset position of the insulating layer on the continuous positive pole piece or the continuous negative pole piece can be effectively ensured, and the production yield of the electrode assembly can be effectively improved.

In some embodiments, the insulating layer is provided with a plurality of holes.

By adopting the scheme, active ions can freely penetrate through the pores of the insulating layer and the diaphragm in the charging and discharging process of the battery cell, so that the active ions can move between the positive electrode plate and the negative electrode plate. Therefore, the arrangement of the insulating layer can be effectively ensured, the charging and discharging processes of the battery cells are not greatly influenced, and the charging and discharging performances of the battery cells can be effectively ensured.

In some embodiments, the absolute value of the difference in porosity of the insulating layer and the porosity of the separator is less than or equal to 25%.

Through adopting above-mentioned scheme, can make the porosity of insulating layer little with the porosity of diaphragm differ greatly, based on this, can be convenient for active ion freely, normally pierce through insulating layer and diaphragm to can effectively ensure that the setting of insulating layer can not cause great influence to the battery monomer charge-discharge process, can effectively ensure the free charge-discharge performance of battery.

In some embodiments, the absolute value of the difference in porosity of the insulating layer and the porosity of the separator is less than or equal to 10%.

Through adopting above-mentioned scheme, can make the porosity of insulating layer close with the porosity of diaphragm and set up, so, can be convenient for active ion freely, normally pierce through insulating layer and diaphragm to can effectively ensure that the setting of insulating layer can not cause great influence to the battery monomer charge-discharge process, can effectively ensure the free charge-discharge performance of battery.

In some embodiments, the insulating layer is a polyolefin separator.

Through adopting above-mentioned scheme, the insulating layer is made to the accessible polyolefin diaphragm such as polypropylene diaphragm to ensure that the porosity of insulating layer is close with the porosity of diaphragm and sets up even the same setting, thereby can ensure that active ion can freely, normally pierce through insulating layer and diaphragm, can effectively ensure that the setting of insulating layer can not cause great influence to the battery monomer charge-discharge process, can effectively ensure the free charge-discharge performance of battery.

In some embodiments, the insulating layer has a porosity of 40% to 50%.

By adopting the scheme, on one hand, the air permeability of the insulating layer can be ensured to be moderate, and active ions can be ensured to freely and normally penetrate through the insulating layer. On the other hand, the glue amount of the glue layer penetrating into the pores of the insulating layer when being coated on the side surface of the insulating layer can be guaranteed to be smaller, and the glue amount remained on the surface of the insulating layer is larger, so that the adhesive force of the glue layer can be guaranteed, the reliable fixation of the insulating layer and the pole piece can be guaranteed, the blocking influence of the glue layer on the pores of the insulating layer can be reduced, the active ions can freely and normally penetrate the insulating layer, and the conductivity can be guaranteed.

In some embodiments, the pores of the insulating layer have a pore diameter A and the insulating layer has a thickness B, 24.ltoreq.B/A.ltoreq.400.

By adopting the scheme, the thickness B of the insulating layer and the aperture A of the hole of the insulating layer are moderate, and on the basis of the thickness B and the aperture A, dendrites are not easy to puncture the insulating layer or penetrate through the insulating layer, so that the blocking effect of the insulating layer on dendrites can be ensured; on the other hand, the active ions can be easily shuttled in the insulating layer, and the shuttle path is shorter, so that the risk of precipitation of the active ions due to difficult shuttle can be reduced. Therefore, the service life of the battery monomer can be effectively prolonged, and the safety of the battery monomer can be effectively improved.

In some embodiments, the aperture a of the aperture of the insulating layer is 0.05um to 0.5um.

By adopting the scheme, on one hand, the air permeability of the insulating layer can be ensured to be moderate, and the active ions can freely and normally penetrate through the pores of the insulating layer. On the one hand, the adhesive layer can be ensured to be less in the amount of glue penetrating into the pores of the insulating layer when being coated on the side surface of the insulating layer, and the amount of glue reserved on the surface of the insulating layer is more, so that the adhesive force of the adhesive layer can be ensured, the insulating layer can be reliably fixed with the pole piece through the adhesive layer, the blocking influence of the adhesive layer on the pores of the insulating layer can be reduced, the active ions can freely and normally penetrate the insulating layer, and the conductivity can be ensured. On the one hand, can guarantee the insulating layer to the separation effect of the dendrite that grows from the defect of diaphragm during battery monomer use to reduce the risk of growing dendrite from the aperture of insulating layer, thereby can correspondingly prolong battery monomer's life, can correspondingly promote battery monomer's security.

In some embodiments, the thickness B of the insulating layer is 12um to 20um.

Through adopting above-mentioned scheme, can ensure that insulating layer's thickness B is moderate to on the insulating layer can form better insulating separation effect to the dendrite of its growth of assurance insulating layer, reduce the influence of insulating layer to the free energy density of battery and the penetration rate of active ion penetration insulating layer, thereby can ensure the conductivity, can ensure the free charge-discharge performance of battery, can correspondingly prolong the free life of battery, can correspondingly promote the free security of battery.

In some embodiments, the glue layer is recessed from the hole in the thickness direction of the insulating layer.

Through adopting above-mentioned scheme, can reduce the shutoff influence of glue film to the hole of insulating layer to a great extent on the basis of the fastening utility of glue film to the insulating layer to can be convenient for active ion freely pierce through the hole of insulating layer and diaphragm in the free charge-discharge process of battery, and realize moving between positive pole piece and negative pole piece, thereby can effectively reduce the influence of the setting of insulating layer to the free charge-discharge process of battery, can effectively ensure the free charge-discharge performance of battery.

In some embodiments, the insulating layer has a tensile strength in its width direction of greater than or equal to 1000 kilograms force per square centimeter (kgf/cm) ² )。

Through adopting above-mentioned scheme, can ensure that the insulating layer has sufficient tensile strength in its width direction, can effectively reduce the insulating layer and take place the risk of fracture, fracture defect under the pulling force effect to can ensure and improve the insulating separation utility of insulating layer to the dendrite that grows out from the defect department of diaphragm, can effectively reduce the dendrite and follow the fracture of insulating layer, fracture defect continuation growth's risk, thereby can correspondingly prolong battery monomer's life, can correspondingly promote battery monomer's security.

In some embodiments, the insulating layer has an elongation in its width direction of greater than or equal to 10%.

Through adopting above-mentioned scheme, can ensure that the insulating layer has sufficient elongation at its width direction to ensure that the insulating layer can be along with electrode assembly adaptability extension deformation, thereby can ensure that the utility scope of insulating layer can cover the corresponding region of pole piece, can ensure that the insulating layer can form reliable insulation separation utility to the dendrite that grows out from the defect of diaphragm.

In some embodiments, the insulating layer has a shrinkage of 0-3% at 105 degrees celsius (c).

Through adopting above-mentioned scheme, can guarantee that the insulating layer is less along with the size shrink degree that the inside temperature of battery monomer took place during the battery monomer uses to can ensure that the utility scope of insulating layer can cover the corresponding region of pole piece, can ensure that the insulating layer can form reliable insulating separation utility to the dendrite that grows out from the defect of diaphragm.

In a second aspect, a battery is provided, the battery including a battery cell provided in embodiments of the present application.

Through adopting above-mentioned scheme, battery accessible uses the battery monomer that this application embodiment provided, ensures and prolongs the life of battery, ensures and improves the safety in utilization of battery.

In a third aspect, an electrical device is provided, where the electrical device includes a battery or a battery cell provided in an embodiment of the present application.

Through adopting above-mentioned scheme, the battery or the battery monomer that the power consumption device accessible provided of this application embodiment are used, guarantee and extension power consumption device's life, guarantee and improve power consumption device's safety in utilization.

Drawings

In order to clearly illustrate the technical solutions in the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application or the exemplary technical descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application;

FIG. 2 is an exploded view of a battery provided in an embodiment of the present application;

fig. 3 is an exploded schematic view of a battery cell according to an embodiment of the present disclosure;

fig. 4 is a schematic cross-sectional view of a battery cell according to an embodiment of the present disclosure;

fig. 5 is a schematic structural view of an electrode assembly according to an embodiment of the present application;

FIG. 6 is a partial schematic view of the electrode assembly provided in FIG. 5;

FIG. 7 is a partial schematic view of the electrode assembly provided in FIG. 5;

fig. 8 is a schematic structural diagram of an insulating layer and a glue layer according to an embodiment of the present application, where a plurality of strip-shaped colloids are disposed at intervals along a width direction of the insulating layer;

fig. 9 is a schematic structural diagram of an insulating layer and a glue layer according to another embodiment of the present disclosure, where a plurality of strip-shaped colloids are disposed at intervals along a length direction of the insulating layer;

fig. 10 is a schematic structural diagram of an insulating layer and a glue layer according to another embodiment of the present application, wherein at least a portion of the bulk glue is distributed at each corner of the insulating layer.

Wherein, each reference sign in the figure:

1-battery, 2-controller, 3-motor; 100-battery unit, 200-box, 201-first part, 202-second part;

10-electrode components, 11-positive electrode pieces, 111-positive electrode lugs, 112-an innermost positive electrode piece, 12-negative electrode pieces, 121-negative electrode lugs, 122-an innermost negative electrode piece, 123-a secondary negative electrode piece, 13-a diaphragm, 14-an insulating layer, 141-a bending section, 142-an extending section, 15-a glue layer, 151-a colloid, 16-a main body area and 17-a bending area; 20-electrolyte; 30-case, 40-end cap, 50-electrode terminal.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved by the present application clear, the present application is described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

In the description of the present application, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In this application, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like 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 terms in this application will be understood by those of ordinary skill in the art as the case may be.

The battery cell is the smallest unit that stores and outputs electrical energy. At least one electrode assembly is generally disposed inside the battery cell. The electrode assembly is a component in which electrochemical reactions occur in the battery cells. The electrode assembly includes a positive electrode tab, a negative electrode tab, and a separator separating the positive electrode tab and the negative electrode tab. The positive electrode sheet, the separator and the negative electrode sheet may be wound to form a rolled electrode assembly such that the electrode assembly has a body region and a bent region disposed at an end side of the body region. When the battery cell is charged, the positive electrode plate can generate active ions, and the active ions provided by the positive electrode plate can penetrate through the pores of the diaphragm to move to the negative electrode plate and are embedded into the negative electrode active material of the negative electrode plate; on the contrary, when the battery cell discharges, active ions embedded in the negative electrode active material of the negative electrode plate are extracted, and the active ions extracted from the negative electrode plate can penetrate through the pores of the diaphragm to move to the positive electrode plate and are embedded in the positive electrode active material of the positive electrode plate.

However, the applicant found that:

1. in the bending region, since the positive electrode plate of any ring is located at the outer side of the negative electrode plate of the same ring, the curvature radius of the positive electrode plate of any ring is relatively larger than that of the negative electrode plate of the same ring, for example, since the positive electrode plate of the innermost ring is located at the outer side of the negative electrode plate of the innermost ring, the curvature radius of the positive electrode plate of the innermost ring is relatively larger than that of the negative electrode plate of the innermost ring. Based on the above, in the bending area, the area of the positive electrode plate of any ring is relatively larger than that of the negative electrode plate of the same ring, so that in the charging process of a battery cell, more active ions are generated by the positive electrode plate with larger area and more positive electrode active substances, but the negative electrode plate with smaller area and less negative electrode active substances is not provided with enough positions for the active ions to be embedded, so that the active ions which cannot be embedded into the negative electrode active substances are precipitated, and a metal precipitation phenomenon is generated.

2. During the process of winding the positive electrode plate, the diaphragm and the negative electrode plate to form the rolled electrode assembly, the bending parts of the positive electrode plate and the negative electrode plate (namely, the parts of the electrode plates corresponding to the bending areas) are bent and bent, and the smaller the curvature radius of the inner ring is, the part of positive electrode active material at the bending parts of the positive electrode plate can fall off (namely, the powder falling phenomenon occurs), and the powder falling phenomenon also occurs in the negative electrode active material at the bending parts of the negative electrode plate. And the curvature radius of the negative electrode plate of any circle is relatively smaller than that of the positive electrode plate of the same circle, so that the powder falling phenomenon of the bending part of the negative electrode plate during bending can be relatively serious. The powder falling phenomenon can reduce the content of active substances on the pole piece, so that the position for embedding active ions in the negative pole piece with reduced negative electrode active substances is reduced in the charging process of the battery cell, and the active ions which cannot be embedded into the negative electrode active substances are increased, so that the metal precipitation phenomenon is aggravated.

3. During winding and pre-pressing forming of the electrode assembly and during use of the battery cell, the bent parts of the positive electrode plate and the negative electrode plate can bear larger stress due to bending, and the smaller the curvature radius of the inner ring is, the larger the stress is, so that tearing defects can occur at the bent parts of the positive electrode plate and the negative electrode plate. If a tearing defect occurs, the active material at the tearing position can fall off, so that the active material cannot be embedded and the precipitated active ions are increased in the charging and discharging process of the battery monomer, thereby increasing the metal precipitation phenomenon.

Based on this, the applicant found that the bent region of the electrode assembly is susceptible to a metal precipitation phenomenon during the use of the battery cell. The continuous diaphragm may have defects of larger aperture, breakage and the like in a local area, so that dendrites are easy to grow at the defects of the diaphragm in the bending area due to the separated active ions along with the extension of the service time of the battery monomer. With the growth of dendrites, dendrites are easy to contact and conduct the positive electrode plate and the negative electrode plate, so that the internal short circuit of the battery cell is caused, and the safety of the battery cell is affected. And during the short circuit, dendrites can heat and melt the diaphragm part at the periphery of dendrites, so that the diaphragm defect is enlarged, and the positive electrode plate part and the negative electrode plate part at the part where the diaphragm is melted are in direct contact with the short circuit, thereby aggravating the short circuit phenomenon and seriously affecting the safety of the battery cell.

From this, some embodiments of this application provide a battery monomer, this battery monomer can be firm with the insulating layer through the glue film, reliably bond to the kink of arbitrary circle positive pole piece or negative pole piece, in order during electrode assembly coiling and pre-compaction shaping, and during battery monomer use, through the insulating layer that locates the kink district, the bending stress that bears the kink of pole piece forms buffering utility, thereby can effectively reduce the risk that the kink of pole piece appears tearing the defect and lead to the active material to reduce, can effectively reduce the kink district of electrode assembly and aggravate the risk of separating out the metal phenomenon because of the active material reduces, can effectively alleviate the growth rate of dendrite, thereby can correspondingly lengthen the free life of battery, can correspondingly promote the free security of battery. And even if dendrite grows in the bending area of the electrode assembly along with the extension of the service time, the battery monomer can form insulation obstruction to dendrite growing towards the battery monomer through the insulation layer with insulation characteristic, so that the dendrite is prevented from directly contacting and conducting the positive pole piece and the negative pole piece, and even the growth of the dendrite is prevented and delayed, thereby effectively delaying the phenomenon that the dendrite directly causes internal short circuit of the battery monomer, effectively delaying the phenomenon that the dendrite heats and melts off the diaphragm at the periphery of the dendrite due to short circuit, causing the phenomenon that the part of the positive pole piece and the part of the negative pole piece at the part where the diaphragm is melted are directly contacted and short-circuited, correspondingly prolonging the service life of the battery monomer and correspondingly improving the safety of the battery monomer.

The battery cells disclosed in the embodiments of the present application may be used independently, or may be combined with other battery cells to form a modularized battery, such as a battery module, or a battery pack, which is capable of providing higher voltage and capacity. The battery cell and the battery disclosed by the embodiment of the application can be used for an electric device using the battery cell and the battery as power sources or various energy storage systems using the battery cell and the battery as energy storage elements. The powered device may be, but is not limited to, a vehicle, a cell phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like. Spacecraft include airplanes, rockets, space planes, spacecraft, and the like. The electric toy includes fixed or mobile electric toys such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy, and the like. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others.

In order to explain the technical solution provided in the present application, the following description will take "electric device as vehicle" as an example with reference to the specific drawings and embodiments.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like. The interior of the vehicle is provided with a battery 1, and the battery 1 may be provided at the bottom or at the head or at the tail of the vehicle. The battery 1 is used to supply power to the vehicle, for example, the battery 1 may serve as an operating power source for the vehicle. The vehicle may further comprise a controller 2 and a motor 3, the controller 2 being arranged to control the battery 1 to power the motor 3, for example for starting, navigating and operating power requirements of the vehicle.

In some embodiments of the present application, the battery 1 may be used not only as an operating power source of a vehicle, but also as a driving power source of the vehicle, instead of or in part instead of fuel oil or natural gas, to supply driving power to the vehicle.

Referring to fig. 2, fig. 2 is an exploded view of a battery 1 according to some embodiments of the present application. The battery 1 includes a battery cell 100 and a case 200, and the battery cell 100 is accommodated in the case 200. The case 200 is used to provide an accommodating space for the battery unit 100, and the case 200 may have various structures. In some embodiments, the case 200 may include a first portion 201 and a second portion 202, the first portion 201 and the second portion 202 being overlapped with each other, the first portion 201 and the second portion 202 together defining an accommodating space for accommodating the battery cell 100. The second portion 202 may be a hollow structure with one end opened, the first portion 201 may be a plate-shaped structure, and the first portion 201 covers the opening side of the second portion 202, so that the first portion 201 and the second portion 202 together define an accommodating space; the first portion 201 and the second portion 202 may also be hollow structures with one side open, and the open side of the first portion 201 is engaged with the open side of the second portion 202. Of course, the case 200 formed by the first portion 201 and the second portion 202 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc.

In the battery 1, the plurality of battery units 100 may be provided, and the plurality of battery units 100 may be connected in series, in parallel, or in series-parallel, where the series-parallel connection means that the plurality of battery units 100 are connected in both series and parallel.

Specifically, the battery cell 100 may be a battery cell. The plurality of battery cells can be directly connected in series, in parallel or in series-parallel, and then the whole formed by the plurality of battery cells is accommodated in the box body 200. The battery cell can be a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery or a magnesium ion battery, etc.; the battery cell can be in a cylinder, a flat body, a cuboid or other shapes, etc.; the battery cells can adopt different packaging modes to form cylindrical battery cells, square battery cells or soft package battery cells and the like; the present application is not limited in this regard.

Alternatively, the battery cell 100 may be a battery module or a battery module. The battery cells can be connected in series or in parallel or in series-parallel to form a modularized structure, namely a battery module or a battery module; the plurality of battery modules or the battery modules are connected in series or in parallel or in series-parallel to form a whole and are accommodated in the case 200.

Of course, the battery 1 may also include other structures, for example, the battery 1 may also include a bus member (not shown in the drawings) for making electrical connection between the plurality of battery cells 100.

Of course, in some embodiments, the battery 1 may not include the case 200, but a plurality of battery cells may be electrically connected and integrated by a necessary fixing structure to be assembled into the power consumption device.

Referring to fig. 3 and 4, fig. 3 and 4 are schematic structural diagrams of a battery cell according to some embodiments of the present application. The battery cell is the smallest unit that stores and outputs electrical energy. The battery cell includes the electrode assembly 10, the electrolyte 20, the case 30, the end cap 40, and the like.

The end cap 40 refers to a member that is covered at the opening of the case 30 to isolate the inner environment of the battery cell from the outer environment. In some embodiments, the shape of the end cap 40 may be adapted to the shape of the housing 30 to mate with the housing 30. In some embodiments, the end cover 40 may be made of a material having a certain hardness and strength, so that the end cover 40 is not easy to deform when being extruded and collided, so that the battery unit can have higher structural strength and safety performance can be improved. Of course, the material of the end cap 40 is not limited in this embodiment, and the end cap 40 may be made of copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, functional components such as electrode terminals 50 may be provided on the end cap 40. The electrode terminal 50 may be used to be electrically connected with the electrode assembly 10 for outputting or inputting electric power. In some embodiments, a pressure relief mechanism (not shown) may also be provided on the end cap 40 for venting the internal pressure of the battery cell when the internal pressure or temperature reaches a threshold. In some embodiments, insulation (not shown) may also be provided on the inside of the end cap 40, which may be used to isolate electrical connection components within the housing 30 from the end cap 40 to reduce the risk of short circuits. Alternatively, the insulator may be plastic, rubber, or the like.

The housing 30 is a component for mating with the end cap 40 to form the internal environment of the battery cell. The internal environment defined by the case 30 in cooperation with the cap 40 may be used to accommodate the electrode assembly 10, the electrolyte 20, and the like. In some embodiments, the housing 30 and the end cap 40 may be separate components, and an opening may be provided in the housing 30 to create an internal environment for the battery cell by closing the end cap 40 at the opening. In some embodiments, the end cap 40 and the housing 30 may be integrated, specifically, the end cap 40 and the housing 30 may form a common connection surface before other components are put into the housing, and when the interior of the housing 30 needs to be sealed, the end cap 40 is covered with the housing 30. The housing 30 may be of various shapes and sizes, such as a rectangular parallelepiped, a cylinder, a hexagonal prism, etc. Specifically, the shape of the case 30 may be determined according to the specific shape and size of the electrode assembly 10. The material of the housing 30 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not limited in this embodiment.

The electrode assembly 10 is a component in which electrochemical reactions occur in battery cells. One or more electrode assemblies 10 may be included within the case 30. Referring to fig. 5, the electrode assembly 10 includes a positive electrode tab 11, a negative electrode tab 12, and a separator 13, the separator 13 separating the positive electrode tab 11 and the negative electrode tab 12. The positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 separating the positive electrode sheet 11 and the negative electrode sheet 12 may be processed into a roll-like structure by winding, and the electrode assembly 10 having a roll-like structure has a body region 16 and a bent region 17 disposed at an end side of the body region 16. Wherein the portions of both the positive electrode tab 11 and the negative electrode tab 12 having no active material each constitute a tab, which is a current transmitting end of the electrode assembly 10, for connection with the electrode terminal 50 and transmission of current. The tab of the positive electrode tab 11 is a positive electrode tab 111, and the tab of the negative electrode tab 12 is a negative electrode tab 121, and the positive electrode tab 111 and the negative electrode tab 121 may be located on one side of the main body region 16 together or on opposite sides of the main body region 16 respectively.

The electrolyte 20 is a liquid that wets the electrode assembly 10. When the battery cell is charged, the positive electrode tab 11 generates active ions, and the active ions provided by the positive electrode tab 11 can penetrate the pores of the separator 13, move to the negative electrode tab 12 via the electrolyte 20, and are embedded in the negative active material of the negative electrode tab 12. In contrast, when the battery cell discharges, the active ions embedded in the negative electrode active material of the negative electrode tab 12 are extracted, and the active ions extracted from the negative electrode tab 12 may penetrate the pores of the separator 13, move to the positive electrode tab 11 via the electrolyte 20, and are embedded in the positive electrode active material of the positive electrode tab 11.

Referring to fig. 4, 5, 6, and 7, some embodiments of the present application provide a battery cell including at least one electrode assembly 10. The electrode assembly 10 includes a positive electrode tab 11, a negative electrode tab 12, a separator 13, an insulating layer 14, and a glue layer 15. The positive electrode tab 11, the separator 13, and the negative electrode tab 12 are stacked and wound, and the electrode assembly 10 has a bending region 17. At least a portion of the insulating layer 14 and at least a portion of the adhesive layer 15 are disposed in the bending region 17, and the insulating layer 14 is adhered to the positive electrode tab 11 or the negative electrode tab 12 through the adhesive layer 15. In the thickness direction of the insulating layer 14, the projected area of the adhesive layer 15 is smaller than the projected area of the insulating layer 14.

The electrode assembly 10 is a member in which electrochemical reaction occurs in a battery cell. One or more electrode assemblies 10 may be disposed inside the battery cell.

In the electrode assembly 10, the positive electrode sheet 11 is a continuous positive electrode sheet 11, the negative electrode sheet 12 is a continuous negative electrode sheet 12, and the diaphragm 13 is a continuous diaphragm 13. Two continuous diaphragms 13 are arranged, before winding, one continuous diaphragm 13 is arranged between the continuous positive pole piece 11 and the continuous negative pole piece 12, and the other continuous diaphragm 13 is arranged on one side of the continuous negative pole piece 12, which is away from the continuous positive pole piece 11, or on one side of the continuous positive pole piece 11, which is away from the continuous negative pole piece 12. Based on this, when the positive electrode sheet 11, the separator 13 and the negative electrode sheet 12 are wound and pre-pressed to form a roll-like structure, the two continuous separators 13 can separate the positive electrode sheet 11 and the negative electrode sheet 12 to prevent the positive electrode sheet 11 and the negative electrode sheet 12 from being in direct contact to cause a short circuit. Wherein the membrane 13 has a plurality of pores through which the active ions freely penetrate.

As shown in fig. 5, the electrode assembly 10 having a roll-shaped structure has a body region 16 and a bending region 17, wherein the body region 16 is a portion of the roll-shaped structure opposite to the middle, and the bending region 17 is a portion of the roll-shaped structure opposite to the end of the body region 16 and bent. The number of inflection zones 17 is one or more.

In the electrode assembly 10, the insulating layer 14 may be provided in one bending region 17, or the insulating layer 14 may be provided in each of the bending regions 17. In the inflection region 17 where the insulating layers 14 are provided, one or more insulating layers 14 may be provided. Referring to fig. 8, the length direction a of the insulating layer 14 corresponds to the extending direction of the pole piece, and is also the winding direction of the pole piece; the width direction b of the insulating layer 14 corresponds to the width direction of the pole piece; the thickness direction of the insulating layer 14 is perpendicular to the length direction and the width direction thereof, and also corresponds to the thickness direction of the pole piece.

The insulating layer 14 is provided with a glue layer 15 on one side in the thickness direction thereof. The insulating layer 14 may be adhered to the inner side or the outer side of the bent portion of the positive electrode tab 11 at any turn through the adhesive layer 15, and at this time, the insulating layer 14 is located between the bent portion of the positive electrode tab 11 and the separator 13. The insulating layer 14 may be adhered to the inner side or the outer side of the bending portion of the negative electrode tab 12 at any turn through the adhesive layer 15, and at this time, the insulating layer 14 is located between the bending portion of the negative electrode tab 12 and the separator 13.

Specifically, before winding, the insulating layer 14 may be adhered to a specific position of the continuous positive electrode tab 11 or the continuous negative electrode tab 12 via the adhesive layer 15 to stabilize the relative position and relative state of the insulating layer 14 with respect to the tab. Accordingly, during the winding of the electrode assembly 10, it is ensured that the insulating layer 14 and the adhesive layer 15 can be wound to the bending region 17 in a stable position and state with respect to the electrode sheet, as the continuous positive electrode sheet 11 or the continuous negative electrode sheet 12 is wound. Thereby, the installation of the insulating layer 14 and the adhesive layer 15 can be conveniently and rapidly realized, the electrode assembly 10 can be conveniently and rapidly formed, and the production efficiency and the production yield of the electrode assembly 10 can be effectively ensured and improved.

Wherein, the adhesive layer 15 and the insulating layer 14 have electrolyte resistance, i.e. the adhesive layer 15 and the insulating layer 14 are not easy to dissolve in the electrolyte 20. Based on this, when the electrode assembly 10 and the electrolyte 20 are encapsulated inside the battery cell, and during the use of the battery cell, the insulating layer 14 can be ensured to be reliably adhered and fixed to the pole piece via the adhesive layer 15, so that the relative position and the relative state can be firmly stabilized, the risk of shifting and falling off the insulating layer 14 can be effectively reduced, and the insulating layer 14 can be ensured to play a role in a specific position permanently, stably and reliably during the use of the battery cell.

Wherein the insulating layer 14 has a better insulating property. Based on this, when the insulating layer 14 is provided at the bent portion of the positive electrode tab 11 of any turn, even if active ions are precipitated from the bent portion of the negative electrode tab 12 during the charging process of the battery cell, dendrites grow from the defect of the bent portion of the separator 13 along with the extension of the service time of the battery cell, and the grown dendrites can be insulated and blocked by the insulating layer 14 provided at the bent portion of the positive electrode tab 11 of any turn, so that the dendrites are prevented from directly contacting and conducting the positive electrode tab 11 and the negative electrode tab 12, and the growth rate of dendrites can be blocked and delayed even to some extent. Therefore, the phenomenon that dendrites directly cause internal short circuit of the battery monomer can be effectively delayed, the phenomenon that dendrites heat and melt the diaphragm 13 at the periphery of dendrites due to short circuit and cause direct contact short circuit between the part of the positive pole piece 11 and the part of the negative pole piece 12 at the part where the diaphragm 13 is melted can be effectively delayed, the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

Similarly, when the insulating layer 14 is provided at the bent portion of the arbitrary circle of the negative electrode tab 12, even if active ions are precipitated from the bent portion of the negative electrode tab 12 during the charging of the battery cell, the bent portion of the separator 13 can be shielded and protected by the insulating layer 14 provided at the bent portion of the arbitrary circle of the negative electrode tab 12. Therefore, the phenomenon that the separated active ions break through the insulating layer 14 and grow dendrites from the defect of the bent part of the diaphragm 13 can be effectively delayed, the phenomenon that dendrites directly cause internal short circuit of the battery monomer can be effectively delayed, the phenomenon that the dendrites melt the diaphragm 13 on the periphery of the dendrites due to short circuit, and the part of the positive pole piece 11 and the part of the negative pole piece 12 at the melted part of the diaphragm 13 are directly contacted with the short circuit can be effectively delayed, so that the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

Wherein the insulating layer 14 has a better buffer property. Based on this, during winding and pre-pressing of the electrode assembly 10 and during use of the battery cell, the insulation layer 14 can provide a buffering effect on the larger bending stress borne by the bending portion of the pole piece, so that the risk that the active material is reduced due to tearing defect of the bending portion of the pole piece can be effectively reduced, the risk that the metal phenomenon is aggravated and precipitated in the bending region 17 of the electrode assembly 10 due to the reduction of the active material can be effectively reduced, the growth rate of dendrite can be effectively delayed, the service life of the battery cell can be correspondingly prolonged, and the safety of the battery cell can be correspondingly improved.

Wherein, in the thickness direction of the insulating layer 14, the projected area of the glue layer 15 is smaller than the projected area of the insulating layer 14. That is, the adhesive layer 15 is coated on a partial region of the side surface of the insulating layer 14. Based on this, during winding and pre-compression molding of the electrode assembly 10 and during use of the battery cell, the negative effects of the adhesive layer 15 on the extensibility and deformability of the insulating layer 14 can be effectively reduced on the basis of stabilizing the position and state of the insulating layer 14 relative to the electrode sheet by the adhesive layer 15, so that the insulating layer 14 can be conveniently and adaptively extended and deformed along with the electrode sheet, the insulating layer 14 can be conveniently and permanently and reliably exerted during use of the battery cell, the risk of tearing defects of the insulating layer 14 during use of the battery cell can be effectively reduced, and the service life of the insulating layer 14 can be effectively ensured and prolonged.

In summary, the battery monomer provided by the embodiment of the application can firmly and reliably adhere the insulating layer 14 to the bending part of the positive electrode pole piece 11 or the negative electrode pole piece 12 in any circle through the adhesive layer 15, so that the insulating layer 14 can be permanently and reliably stabilized in the bending area 17 during the use of the battery monomer, the risk of shifting and falling off of the insulating layer 14 can be effectively reduced, and the insulating layer 14 can be ensured to be permanently, stably and reliably exerted in a specific position during the use of the battery monomer. And, also through making the projected area of glue film 15 in the thickness direction of insulating layer 14 be less than the projected area of insulating layer 14 in its thickness direction, in order to during electrode assembly 10 coiling and pre-compaction shaping and during battery cell use, effectively reduce the negative effect of glue film 15 to the extensibility and the deformability of insulating layer 14, thereby can be convenient for insulating layer 14 to take place to extend, warp along with the pole piece adaptation, can be convenient for insulating layer 14 lasting, reliably exert the utility during battery cell use, can effectively reduce insulating layer 14 and appear tearing the risk of defect during battery cell use, can ensure and prolong insulating layer 14's life correspondingly.

On this basis, the battery monomer that this application embodiment provided can also be in electrode assembly 10 coiling and pre-compaction shaping period and in battery monomer use period, through locating the insulating layer 14 of buckling district 17, the bending stress that the buckling part of pole piece bore forms buffering utility to can effectively reduce the risk that the tearing defect leads to the active material to reduce appears in the buckling part of pole piece, can effectively reduce electrode assembly 10 buckling district 17 and aggravate the risk of separating out the metal phenomenon because of the active material reduces, can effectively alleviate dendrite's growth rate, thereby can correspondingly prolong battery monomer's life, can correspondingly promote battery monomer's security. And, even if dendrite grows in the bending region 17 of the electrode assembly 10 along with the extension of the service time, insulation obstruction can be formed on dendrite growing towards the dendrite through the insulating layer 14 with insulation characteristics, the dendrite can be prevented from directly contacting and conducting the positive pole piece 11 and the negative pole piece 12, and even the growth of dendrite can be prevented and delayed, so that the phenomenon that dendrite directly causes internal short circuit of a battery cell can be effectively delayed, the phenomenon that dendrite is heated and melted due to short circuit to the diaphragm 13 on the periphery of dendrite can be effectively delayed, the phenomenon that the part of the positive pole piece 11 and the part of the negative pole piece 12 at the melted part of the diaphragm 13 directly contact and short circuit can be correspondingly prolonged, and the service life of the battery cell can be correspondingly improved, and the safety of the battery cell can be correspondingly improved.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the adhesive layer 15 includes a plurality of colloids 151, and at least a portion of the colloids 151 are distributed in the edge region of the insulating layer 14.

It should be noted that, based on the setting that "the projected area of the adhesive layer 15 is smaller than the projected area of the insulating layer 14 in the thickness direction of the insulating layer 14", the adhesive layer 15 is divided into a plurality of colloids 151 in this embodiment, and any two colloids 151 may be disposed in an abutting manner or may be disposed at intervals, which is not limited in this embodiment.

The insulating layer 14 has a multi-sided edge along one side in the thickness direction thereof. For example, when the insulating layer 14 has a rectangular parallelepiped shape, one side of the insulating layer 14 in the thickness direction thereof has four side edges.

At least a portion of the plurality of colloids 151 is disposed in an edge region of the insulating layer 14, that is, at least a portion of the colloids 151 are disposed near an edge of the insulating layer 14. For example, a glue 151 may be provided adjacent to one side edge of the insulating layer 14. For another example, four colloids 151 may be disposed near four side edges of the insulating layer 14, respectively.

By adopting the above scheme, the insulating layer 14, particularly the edge of the insulating layer 14, can be firmly and reliably adhered to the bending part of the positive electrode pole piece 11 or the negative electrode pole piece 12 of any circle through the plurality of colloids 151, particularly the colloids 151 which are arranged close to the edge of the insulating layer 14, so that the insulating layer 14 can be permanently and reliably stable in position and play a role. And, can also be on the basis of guaranteeing the fastening utility of glue film 15 to insulating layer 14, do benefit to the setting quantity and the occupation area of reduction colloid 151 to can effectively reduce the negative effect of glue film 15 to insulating layer 14's extensibility and deformability, thereby can be convenient for insulating layer 14 take place to extend, warp along with the pole piece adaptation, can be favorable to guaranteeing insulating layer 14's utility and life.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the colloid 151 is a strip-shaped colloid 151, and a plurality of colloids 151 are disposed at intervals along the width direction b of the insulating layer 14.

It should be noted that the colloid 151 is a strip-shaped colloid 151, i.e. the colloid 151 is arranged in a strip-shaped extending manner. The plurality of colloids 151 are arranged at intervals along the width direction b of the insulating layer 14, that is, the plurality of colloids 151 are sequentially arranged at intervals along the width direction b of the insulating layer 14. Wherein the extending direction of the gel 151 intersects the width direction b of the insulating layer 14, for example, the extending direction of the gel 151 may be parallel to the length direction a of the insulating layer 14.

By adopting the above scheme, the plurality of strip-shaped colloids 151 can be sequentially arranged at intervals along the width direction b of the insulating layer 14, so that the plurality of colloids 151 can be optimally distributed on one side of the insulating layer 14, and particularly, two colloids 151 farthest along the width direction b of the insulating layer 14 can be respectively arranged close to two side edges of the insulating layer 14. On the one hand, on the other hand, the strip-shaped colloid 151 can be ensured to firmly and reliably adhere the insulating layer 14, particularly, the two side edges of the insulating layer 14, to the bending parts of any ring of pole pieces, so that the insulating layer 14 can permanently and reliably stabilize the position and exert the effect. On the one hand, on the basis of optimizing the layout of each strip-shaped colloid 151 so as to ensure the fastening effect on the insulating layer 14, the number of the colloid 151 and the occupied area can be effectively reduced, so that the negative influence of the adhesive layer 15 on the extensibility and the deformability of the insulating layer 14 can be effectively reduced, the insulating layer 14 can be conveniently and adaptively extended and deformed along with the pole piece, and the effect and the service life of the insulating layer 14 can be conveniently ensured. On the one hand, the plurality of strip-shaped colloid 151 can be pulled apart and deformed along with the insulation layer 14 in a distance and extension way during the period that the insulation layer 14 is extended and deformed along with the pole piece, so that the insulation layer 14 can be ensured to be fastened permanently and reliably.

Referring to fig. 6, 7 and 9, in some embodiments of the present application, the colloid 151 is a strip-shaped colloid 151, and a plurality of colloids 151 are disposed at intervals along the length direction a of the insulating layer 14.

It should be noted that the colloid 151 is a strip-shaped colloid 151, i.e. the colloid 151 is arranged in a strip-shaped extending manner. The plurality of colloids 151 are arranged at intervals along the length direction a of the insulating layer 14, that is, the plurality of colloids 151 are sequentially arranged at intervals along the length direction a of the insulating layer 14. Wherein the extending direction of the gel 151 intersects the length direction a of the insulating layer 14, for example, the extending direction of the gel 151 may be parallel to the width direction b of the insulating layer 14.

Through adopting above-mentioned scheme, the multiple strip-shaped colloids 151 can be arranged at intervals along the length direction a of the insulating layer 14 in sequence, so that the multiple colloids 151 can be optimally distributed on one side of the insulating layer 14, and especially two colloids 151 furthest apart along the length direction a of the insulating layer 14 can be respectively close to two side edges of the insulating layer 14 for setting. On the one hand, on the other hand, the strip-shaped colloid 151 can be ensured to firmly and reliably adhere the insulating layer 14, particularly, the two side edges of the insulating layer 14, to the bending parts of any ring of pole pieces, so that the insulating layer 14 can permanently and reliably stabilize the position and exert the effect. On the other hand, the arrangement of each strip-shaped colloid 151 can be optimized to ensure the fastening effect on the insulating layer 14, and the setting quantity and occupied area of the colloid 151 can be effectively reduced, so that the negative influence of the adhesive layer 15 on the extensibility and deformability of the insulating layer 14 can be effectively reduced, the insulating layer 14 can be conveniently and adaptively extended and deformed along with the pole piece, and the effect and the service life of the insulating layer 14 can be ensured. On the one hand, the plurality of strip-shaped colloid 151 can be pulled apart and deformed along with the insulation layer 14 in a distance and extension way during the period that the insulation layer 14 is extended and deformed along with the pole piece, so that the insulation layer 14 can be ensured to be fastened permanently and reliably.

Referring to fig. 6, 7 and 10, in some embodiments of the present application, the colloid 151 is a bulk colloid 151, and at least a portion of the colloid 151 is distributed at each corner of the insulating layer 14.

The colloid 151 may be a block colloid 151, for example, a circular block colloid 151, or a rectangular block colloid 151.

The insulating layer 14 has a plurality of corners on one side in the thickness direction, for example, when the insulating layer 14 has a rectangular parallelepiped shape, the insulating layer 14 has four corners on one side in the thickness direction.

Of the plurality of bulk colloids 151, at least a part of the bulk colloids 151 are distributed at each corner of the insulating layer 14, for example, one side of the insulating layer 14 in the thickness direction has four corners, and four or more bulk colloids 151 may be disposed at the four corners of the insulating layer 14, respectively. The bulk gel 151 disposed at each corner of the insulating layer 14 may be disposed near the edge of the insulating layer 14.

By adopting the scheme, the insulating layer 14, particularly the corners and edges of the insulating layer 14, can be firmly and reliably adhered to the bending parts of any ring of pole pieces through the plurality of block colloids 151, particularly the block colloids 151 distributed at the corners of the insulating layer 14, so that the insulating layer 14 can be permanently and reliably stable in position and exert the effect. Moreover, since the colloid 151 is in a block shape, and the plurality of block-shaped colloids 151 can be optimally distributed on one side of the insulating layer 14, the arrangement quantity and occupied area of the colloids 151 can be effectively reduced on the basis of guaranteeing the fastening effect of the adhesive layer 15 on the insulating layer 14, the negative influence of the adhesive layer 15 on the extensibility and deformability of the insulating layer 14 can be effectively reduced, the insulating layer 14 can be conveniently and adaptively extended and deformed along with the pole piece, and the effect and the service life of the insulating layer 14 can be guaranteed. In addition, during the period that the insulating layer 14 adaptively extends and deforms along with the pole piece, the plurality of block-shaped colloids 151 can adaptively pull the distance along with the insulating layer 14, so that the lasting and effective fastening effect of the whole adhesive layer 15 on the insulating layer 14 can be ensured.

Referring to fig. 4, 6 and 7, in some embodiments of the present application, the adhesive layer 15 is a hot melt adhesive resistant to the electrolyte 20.

The hot melt adhesive is a plastic adhesive, is in a solid state at normal temperature, and can be quickly bonded after being heated and melted. The hot melt adhesive has the characteristics of rapid bonding, firm bonding, stable performance, low cost and the like.

By adopting the scheme, the adhesive layer 15 can be formed by the hot melt adhesive with the characteristics of rapid adhesion, firm adhesion, stable performance and the like, so that the insulating layer 14 can be conveniently, rapidly and reliably adhered to the bending part of the pole piece firmly. And, based on the electrolyte 20 resistant characteristic of the hot melt adhesive, the adhesive layer 15 can also be ensured to exert lasting and effective fastening effect on the insulating layer 14 during the use of the battery cell.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, a ratio of a projected area of the adhesive layer 15 to a projected area of the insulating layer 14 is 20% to 50% in a thickness direction of the insulating layer 14.

In the thickness direction of the insulating layer 14, the projected area of the adhesive layer 15 is smaller than the projected area of the insulating layer 14. By dividing the projected area of the glue layer 15 by the projected area of the insulating layer 14, a ratio of the projected area of the glue layer 15 to the projected area of the insulating layer 14 can be obtained, which is 20% to 50%, for example 25%.

By adopting the above scheme, during winding and prepressing of the electrode assembly 10 and during use of the battery cell, the area ratio of the adhesive layer 15 relative to the insulating layer 14 can be effectively reduced on the basis of ensuring the fastening effect of the adhesive layer 15 on the insulating layer 14, so that the negative influence of the adhesive layer 15 on the extensibility and deformability of the insulating layer 14 can be effectively reduced, the insulating layer 14 can be conveniently and adaptively extended and deformed along with the pole piece, the insulating layer 14 can be conveniently and permanently and reliably exerted during use of the battery cell, the risk of tearing defects of the insulating layer 14 during use of the battery cell can be effectively reduced, and the service life of the insulating layer 14 can be effectively ensured and prolonged.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the thickness of the adhesive layer 15 is 2um to 8um.

The thickness of the adhesive layer 15 refers to the dimension of the adhesive layer 15 in the thickness direction thereof, that is, the dimension of the adhesive layer 15 in the thickness direction of the insulating layer 14.

By adopting the scheme, the thickness of the adhesive layer 15 can be effectively reduced on the basis of ensuring the fastening effect of the adhesive layer 15 on the insulating layer 14, so that the energy density of the electrode assembly 10 and the battery cell can be ensured and improved.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, at least one insulating layer 14 is adhered to the inner side of the innermost positive electrode tab 112 through an adhesive layer 15 in the bending region 17.

In the electrode assembly 10, the insulating layer 14 may be provided in one bending region 17, or the insulating layer 14 may be provided in each of the bending regions 17. In the bent region 17 provided with the insulating layers 14, at least one insulating layer 14 is bonded inside the bent portion of the innermost positive electrode tab 112 through the adhesive layer 15.

Since the radius of curvature of the inner ring is smaller, the bending part of the cathode pole piece 112 and the bending part of the anode pole piece 122 are subjected to larger bending stress, and powder is easy to fall off, so that metal precipitation is easy to occur between the bending part of the cathode pole piece 112 and the bending part of the anode pole piece 122. Because the bending part of the cathode pole piece 112 at the innermost ring is relatively positioned at the outer side of the bending part of the anode pole piece 122 at the innermost ring, metal precipitation phenomenon is easy to occur from the bending part of the anode pole piece 122 at the innermost ring in the process of charging the battery cell.

Therefore, by adopting the above scheme, on one hand, when the dendrite grows from the defect of the bent part of the diaphragm 13 due to the fact that the metal is precipitated at the bent part of the cathode pole piece 122 at the innermost ring, and the dendrite grows from the defect of the bent part of the diaphragm 13, the insulation layer 14 arranged at the inner side of the bent part of the anode pole piece 112 at the innermost ring insulates and blocks the grown dendrite so as to prevent the dendrite from directly contacting and conducting the anode pole piece 11 and the cathode pole piece 12, so that the phenomenon that the dendrite directly causes the internal short circuit of the battery cell can be effectively delayed between the anode pole piece 112 at the innermost ring and the cathode pole piece 122 at the innermost ring, the phenomenon that the dendrite directly causes the internal short circuit of the battery cell can be effectively delayed, the phenomenon that the dendrite directly contacts and fuses the part of the anode pole piece 11 and the cathode pole piece 12 at the fused part of the diaphragm 13 is caused, the service life of the battery cell can be correspondingly prolonged, and the safety of the battery cell can be correspondingly improved.

On the other hand, the compressive stress received by the bent portion of the innermost positive electrode tab 112 may be buffered by the insulating layer 14 disposed inside the bent portion of the innermost positive electrode tab 112 during winding and pre-compression molding of the electrode assembly 10 and during use of the battery cell, so as to reduce the risk of the bent portion of the innermost positive electrode tab 112 having tearing defects, resulting in reduced active material; even the tensile stress born by the bending part of the cathode pole piece 122 at the innermost ring can be buffered, so that the risk of active substances reduction caused by tearing defects at the bending part of the cathode pole piece 122 at the innermost ring is reduced. Therefore, the risk of metal precipitation caused by reduction of active substances can be effectively reduced, the growth rate of dendrites between the cathode pole piece 112 at the innermost ring and the anode pole piece 122 at the innermost ring can be effectively relieved, the service life of the battery cell can be correspondingly prolonged, and the safety of the battery cell can be correspondingly improved.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, at least one insulating layer 14 is adhered to the outer side of the cathode sheet 112 at the innermost ring through an adhesive layer 15 in the bending region 17.

In the electrode assembly 10, the insulating layer 14 may be provided in one bending region 17, or the insulating layer 14 may be provided in each of the bending regions 17. In the bent region 17 provided with the insulating layers 14, at least one insulating layer 14 is bonded to the outside of the bent portion of the innermost positive electrode tab 112 through the adhesive layer 15.

Due to the fact that the bending part of the cathode pole piece 112 at the innermost ring receives larger bending stress, by adopting the scheme, the tensile stress received by the bending part of the cathode pole piece 112 at the innermost ring can be buffered through the insulating layer 14 arranged on the outer side of the bending part of the cathode pole piece 112 at the innermost ring during the winding and pre-pressing forming of the electrode assembly 10 and the use of a battery cell, so that the risk of active substance reduction caused by tearing defect at the bending part of the cathode pole piece 112 at the innermost ring is reduced; even the extrusion stress born by the bending part of the negative electrode plate 123 of the secondary inner ring can be buffered, so that the risk of active substances reduction caused by tearing defects of the bending part of the negative electrode plate 123 of the secondary inner ring is reduced. Therefore, the risk of metal precipitation caused by reduction of active substances can be effectively reduced, the growth rate of dendrites between the anode pole piece 112 of the innermost ring and the cathode pole piece 123 of the secondary inner ring can be effectively relieved, the service life of the battery cell can be correspondingly prolonged, and the safety of the battery cell can be correspondingly improved.

The negative electrode plate 123 of the secondary inner ring is a circle of negative electrode plate 12 positioned outside the positive electrode plate 112 of the innermost ring. When the battery cell is charged, active ions provided by the outer surface of the cathode tab 112 of the innermost ring may move to the anode tab 123 of the sub-inner ring and be embedded in the anode active material of the anode tab 123 of the sub-inner ring.

Thus, by adopting the above-described scheme, dendrites grown toward the inside can also be insulated and blocked by the insulating layer 14 disposed outside the bent portion of the cathode tab 112 at the innermost ring during use of the battery cell, so as to prevent dendrites from directly contacting and conducting the cathode tab 112 at the innermost ring and the anode tab 123 at the next inner ring. Therefore, the phenomenon that dendrites directly cause internal short circuit of the battery monomer can be effectively delayed between the positive pole piece 112 of the innermost ring and the negative pole piece 123 of the secondary inner ring, the phenomenon that dendrites melt the diaphragm 13 at the peripheral side of the dendrites due to short circuit, and the phenomenon that the part of the positive pole piece 11 and the part of the negative pole piece 12 at the melted part of the diaphragm 13 are in direct contact with short circuit can be effectively delayed, so that the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, the bending region 17 is provided with two insulating layers 14, wherein one insulating layer 14 is adhered to the inner side of the innermost positive electrode sheet 112 through a glue layer 15, and the other insulating layer 14 is adhered to the outer side of the innermost positive electrode sheet 112 through the glue layer 15.

In the electrode assembly 10, the insulating layer 14 may be provided in one bending region 17, or the insulating layer 14 may be provided in each of the bending regions 17. In the bending region 17 provided with the insulating layer 14, one insulating layer 14 is provided on each of the inner side and the outer side of the bending portion of the cathode sheet 112 at the innermost ring, and the insulating layer 14 is bonded to the sheet by the adhesive layer 15.

Through adopting above-mentioned scheme, bending zone 17 accessible two insulating layers 14, be liable to produce and separate out metal, separate out between the metal condition relatively serious "between the positive pole piece 112 of inner circle and the negative pole piece 122 of inner circle" and "between the positive pole piece 112 of inner circle and the negative pole piece 123 of secondary inner circle", effectively delay short circuit risk, and bear bending stress great, the bending part department of the positive pole piece 112 of inner circle that easily appears tearing the defect effectively alleviates extrusion stress and tensile stress, realize reducing the risk of tearing of buckling, thereby can effectively prolong the free life of battery, can effectively promote the free security of battery. By adopting the above scheme, the number of the insulating layers 14 can be reduced while the utility of the insulating layers 14 is maximized, so that the energy density of the electrode assembly 10 and the battery cells can be ensured and improved.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, the electrode assembly 10 has a body region 16 and a bending region 17 disposed at an end side of the body region 16. The insulating layer 14 has a bent section 141 bent and disposed in the bending region 17, and an extension section 142 connected to an end of the bent section 141 and disposed in the body region 16.

As shown in fig. 5, the electrode assembly 10 having a rolled structure has a main body region 16 and a bending region 17, wherein the main body region 16 is a relatively flat portion of the rolled structure disposed at the middle, and the bending region 17 is a portion of the rolled structure disposed at the end of the main body region 16.

The insulating layer 14 has a curved section 141, and the curved section 141 of the insulating layer 14 is disposed at the curved region 17, i.e., inside or outside the curved portion of the pole piece. The insulating layer 14 has one or two extension sections 142, and when one extension section 142 is provided, the extension section 142 is formed by extending from one end of the curved section 141 and is provided in the body region 16; when two extension sections 142 are provided, the two extension sections 142 are respectively formed by extending from opposite ends of the curved section 141 and are both disposed in the main body region 16, and the extension lengths of the two extension sections 142 may be the same or different.

By adopting the above scheme, the setting area of the insulating layer 14 can be correspondingly prolonged, and the preset position of the insulating layer 14 on the continuous positive pole piece 11 or the continuous negative pole piece 12 has a wider fault tolerance range, so that the insulating layer 14 can be effectively ensured to maintain the bending section 141 clamped between the bending part of the pole piece and the diaphragm 13 and the extending section 142 extending to the main body area 16 according to the position fault tolerance when the electrode assembly 10 is wound and formed, thereby effectively reducing the precision requirement on the preset position of the insulating layer 14 on the continuous positive pole piece 11 or the continuous negative pole piece 12, and effectively ensuring and improving the production yield of the electrode assembly 10.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the insulating layer 14 is provided with a plurality of holes.

The insulating layer 14 is provided with a plurality of holes. Since the projected area of the adhesive layer 15 in the thickness direction of the insulating layer 14 is smaller than the projected area of the insulating layer 14 in the thickness direction thereof, at least part of the plurality of holes of the insulating layer 14 is not blocked by the adhesive layer 15. The holes not blocked by the glue layer 15 are free to be penetrated by the active ions.

By adopting the scheme, active ions can freely penetrate through the pores of the insulating layer 14 and the diaphragm 13 in the process of charging and discharging the battery cell, so that the active ions can move between the positive electrode plate 11 and the negative electrode plate 12. Therefore, the arrangement of the insulating layer 14 can be effectively ensured without greatly influencing the charging and discharging process of the battery cells, and the charging and discharging performance of the battery cells can be effectively ensured.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, the absolute value of the difference between the porosity of the insulating layer 14 and the porosity of the separator 13 is less than or equal to 25%.

In this example, the porosity may be determined by a gas substitution method. Specifically, reference may be made to GB/T24586-2009, which is determined by the following steps: the insulating layer 14 or the separator 13 was immersed in methyl ethyl carbonate (EMC), washed, filled into a specific device, and measured by a gas substitution method. The percentage of the pore volume in the insulating layer 14 to the total volume of the insulating layer 14 is the porosity of the insulating layer 14, and the percentage of the pore volume in the diaphragm 13 to the total volume of the diaphragm 13 is the porosity of the diaphragm 13. Specifically, the porosity= (V-V0)/v×100%, where V0 is the true volume and V is the apparent volume.

It should also be noted that the porosity of the insulating layer 14 may be greater than the porosity of the membrane 13, and the difference between the porosity of the insulating layer 14 and the porosity of the membrane 13 may be less than or equal to 25%. For example, the porosity of the insulating layer 14 is 50%, the porosity of the separator 13 is 35%, and the difference between the porosity of the insulating layer 14 and the porosity of the separator 13 is 15%. For another example, the porosity of the insulating layer 14 is 40%, the porosity of the separator 13 is 35%, and the difference between the porosity of the insulating layer 14 and the porosity of the separator 13 is 5%.

The porosity of the insulating layer 14 may also be less than the porosity of the separator 13, and the difference between the porosity of the separator 13 and the porosity of the insulating layer 14 is less than or equal to 25%.

By adopting the scheme, the porosity of the insulating layer 14 is slightly different from the porosity of the diaphragm 13, and based on the porosity, active ions can conveniently penetrate through the insulating layer 14 and the diaphragm 13 freely and normally, so that the arrangement of the insulating layer 14 can be effectively ensured, the charging and discharging process of the battery monomer can not be greatly influenced, and the charging and discharging performance of the battery monomer can be effectively ensured.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, the absolute value of the difference between the porosity of the insulating layer 14 and the porosity of the separator 13 is less than or equal to 10%.

Through adopting above-mentioned scheme, can make the porosity of insulating layer 14 close with the porosity of diaphragm 13 and set up, so, can be convenient for active ion freely, normally pierce through insulating layer 14 and diaphragm 13, and realize moving between positive pole piece 11 and negative pole piece 12 to can effectively ensure that the setting of insulating layer 14 can not cause great influence to the battery monomer charge-discharge process, can effectively ensure the free charge-discharge performance of battery.

Referring to fig. 5, 6 and 7, in some embodiments of the present application, the insulating layer 14 is a polyolefin separator, such as a polypropylene (PP) separator.

Through adopting above-mentioned scheme, the insulating layer 14 is made to the polyolefin diaphragm such as polypropylene diaphragm to ensure that the porosity of insulating layer 14 is close with the porosity of diaphragm 13 and sets up the even the same setting, thereby can ensure that active ion can freely, normally pierce through insulating layer 14 and diaphragm 13, can effectively ensure that the setting of insulating layer 14 can not cause great influence to the battery monomer charge-discharge process, can effectively ensure the battery monomer charge-discharge performance.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the porosity of the insulating layer 14 is 40% to 50%.

Theoretically, the larger the porosity of the insulating layer 14 is, the better the air permeability is. However, as the porosity of the insulating layer 14 increases, the amount of glue penetrating into the pores of the insulating layer 14 increases when the same-quality glue layer 15 is coated on the side surface of the insulating layer 14, the amount of glue remaining on the surface of the insulating layer 14 decreases, so that the air permeability of the insulating layer 14 and the adhesion of the glue layer 15 may be deteriorated, thereby deteriorating the fixing effect of the insulating layer 14 and the pole piece, and deteriorating the penetration rate and the electrical conductivity of active ions.

Therefore, by adopting the above scheme, on one hand, the air permeability of the insulating layer 14 can be ensured to be moderate, and active ions can be ensured to freely and normally penetrate through the insulating layer 14. On the other hand, the glue layer 15 can be ensured to be less in glue amount penetrating into the pores of the insulating layer 14 when being coated on the side surface of the insulating layer 14, and more glue amount is reserved on the surface of the insulating layer 14, so that the adhesive force of the glue layer 15 can be ensured, the insulating layer 14 can be reliably fixed with a pole piece through the glue layer 15, the blocking influence of the glue layer 15 on the pores of the insulating layer 14 can be reduced, the active ions can freely and normally penetrate the insulating layer 14, and the conductivity can be ensured.

Referring to FIGS. 6, 7 and 8, in some embodiments of the present application, the hole diameter of the hole of the insulating layer 14 is A, the thickness of the insulating layer 14 is B, and 24.ltoreq.B/A.ltoreq.400.

The insulating layer 14 has a plurality of pores, and the pore diameter a of the pores of the insulating layer 14 refers to the radial dimension of each pore of the insulating layer 14.

It is understood that the pore diameters a of the pores of the insulating layer 14 may be identical or different, and the pore diameters may be the same pore diameters of the pores or the pore diameters of any part of the pores in which the pore diameters of the pores are not identical.

It will be appreciated that the shape of each aperture of the insulating layer 14 may be circular or may be other shapes such as rectangular. When the shape of the hole is circular, the aperture A of the hole refers to the diameter of the hole; when the shape of the hole is rectangular or the like, the aperture a of the hole refers to the dimension of the hole in the radial direction perpendicular to the central axis.

The thickness B of the insulating layer 14 also refers to the dimension of the insulating layer 14 in the thickness direction a thereof.

B/a refers to the ratio of the thickness B of the insulating layer 14 to the pore diameter a of the pores of the insulating layer 14 in the same unit.

When B/a is less than 24, the thickness B of the insulating layer 14 is too small, and the pore diameter a of the pores of the insulating layer 14 is too large, and at this time, dendrites may easily pierce the insulating layer 14 or penetrate the insulating layer 14, thereby failing to provide a blocking effect.

When B/a is greater than 400, the thickness B of the insulating layer 14 may be too large, and the pore diameter a of the pores of the insulating layer 14 may be too small, at this time, the path of the active ions traveling in the insulating layer 14 may be too long, and since the pore diameter a of the pores of the insulating layer 14 is too small, the active ions may be difficult to travel, which may easily cause more active ions to be precipitated.

Therefore, by adopting the scheme, the thickness B of the insulating layer 14 and the aperture A of the hole of the insulating layer 14 are both moderate, and on the one hand, dendrites are not easy to puncture the insulating layer 14 or penetrate the insulating layer 14, so that the blocking effect of the insulating layer 14 on dendrites can be ensured; on the other hand, the active ions can be made to shuttle easily in the insulating layer 14 and the shuttle path is short, so that the risk of precipitation of the active ions due to the difficulty in shuttling can be reduced. Therefore, the service life of the battery monomer can be effectively prolonged, and the safety of the battery monomer can be effectively improved.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the hole diameter of the hole of the insulating layer 14 is 0.05um to 0.5um.

Theoretically, the larger the pore diameter of the pores of the insulating layer 14, the better the air permeability. However, as the pore diameter of the pores of the insulating layer 14 increases, the amount of glue penetrating into the pores of the insulating layer 14 increases when the same-quality glue layer 15 is coated on the side surface of the insulating layer 14, the amount of glue remaining on the surface of the insulating layer 14 decreases, so that the air permeability of the insulating layer 14 and the adhesion force of the glue layer 15 become poor, thereby deteriorating the fixing effect of the insulating layer 14 and the pole piece, and deteriorating the penetration rate and the electrical conductivity of active ions. Also, as the pore diameter of the pores of the insulating layer 14 increases, the barrier effect of the insulating layer 14 against dendrites grown from defects of the separator 13 may be deteriorated during use of the battery cell, and even there may be a risk of dendrite growth from the pores of the insulating layer 14.

Therefore, by adopting the above scheme, on one hand, the air permeability of the insulating layer 14 can be ensured to be moderate, and active ions can be ensured to freely and normally penetrate through the pores of the insulating layer 14. On the one hand, the glue layer 15 can be ensured to be less in glue amount penetrating into the pores of the insulating layer 14 when being coated on the side surface of the insulating layer 14, and the glue amount remained on the surface of the insulating layer 14 is more, so that the adhesive force of the glue layer 15 can be ensured, the insulating layer 14 can be reliably fixed with a pole piece through the glue layer 15, the blocking influence of the glue layer 15 on the pores of the insulating layer 14 can be reduced, the active ions can freely and normally penetrate the insulating layer 14, and the conductivity can be ensured. On the one hand, the blocking effect of the insulating layer 14 on dendrites growing from the defects of the diaphragm 13 can be guaranteed during the use of the battery monomer, and the risk of dendrites growing from the pores of the insulating layer 14 is reduced, so that the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the thickness of the insulating layer 14 is 12um to 20um.

It should be noted that, in theory, the greater the thickness of the insulating layer 14, the better the insulating barrier effect of the insulating layer 14 against dendrites. However, as the thickness of the insulating layer 14 increases, the energy density of the battery cell may decrease, and the penetration rate of active ions through the insulating layer 14 may be deteriorated, thereby causing deterioration of conductivity and even aggravation of the metal precipitation phenomenon.

Therefore, by adopting the scheme, the thickness of the insulating layer 14 can be ensured to be moderate, so that on the basis that the insulating layer 14 can form a better insulating and blocking effect on dendrites growing towards the insulating layer, the influence of the insulating layer 14 on the energy density of the battery monomer and the penetration rate of active ions penetrating through the insulating layer 14 can be reduced, the conductivity can be ensured, the charge and discharge performance of the battery monomer can be ensured, the service life of the battery monomer can be correspondingly prolonged, and the safety of the battery monomer can be correspondingly improved.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the glue layer 15 is avoided from the hole in the thickness direction of the insulating layer 14.

It should be noted that, based on the setting that "the projected area of the adhesive layer 15 is smaller than the projected area of the insulating layer 14 in the thickness direction of the insulating layer 14", the present embodiment can set the adhesive layer 15 to avoid and avoid the hole of the insulating layer 14, so as to avoid the adhesive layer 15 from blocking the hole of the insulating layer 14.

By adopting the scheme, the blocking influence of the adhesive layer 15 on the holes of the insulating layer 14 can be greatly reduced on the basis of ensuring the fastening effect of the adhesive layer 15 on the insulating layer 14, so that active ions can freely penetrate through the holes of the insulating layer 14 and the diaphragm 13 in the battery monomer charging and discharging process, and can move between the positive electrode pole piece 11 and the negative electrode pole piece 12, the influence of the setting of the insulating layer 14 on the battery monomer charging and discharging process can be effectively reduced, and the battery monomer charging and discharging performance can be effectively ensured.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the insulating layer 14 has a tensile strength in the width direction b of 1000kgf/cm or more ² 。

The length direction a of the insulating layer 14 corresponds to the extending direction of the pole piece, and is also the winding direction of the pole piece, and the width direction b of the insulating layer 14 corresponds to the width direction of the pole piece. By applying a tensile force in the width direction b to the insulating layer 14 until the insulating layer 14 cannot withstand the tensile force and is broken, the tensile strength of the insulating layer 14 in the width direction b thereof can be measured. The tensile strength of the insulating layer 14 in the width direction b thereof can reflect the ability of the insulating layer 14 to resist damage in the width direction b thereof when subjected to a tensile force.

Since the insulating layer 14 is disposed at the bending region 17, the insulating layer 14 receives a certain tensile force during the winding and pre-compression molding of the electrode assembly 10 and during the use of the battery cell. Based on this, through adopting above-mentioned scheme, can ensure that insulating layer 14 has sufficient tensile strength at its width direction b, can effectively reduce insulating layer 14 and take place fracture, the risk of fracture defect under the pulling force effect to can ensure and improve insulating layer 14 to the insulating separation utility of dendrite that grows out from the defect of diaphragm 13, can effectively reduce dendrite along insulating layer 14 fracture, the risk that fracture defect continues to grow of fracture, thereby can correspondingly prolong battery monomer's life, can correspondingly promote battery monomer's security.

It is added that when the insulating layer 14 has a sufficient tensile strength in the width direction b thereof, the tensile strength of the insulating layer 14 in the extending direction thereof is basically sufficient. Therefore, the tensile strength of the insulating layer 14 in the extending direction thereof is not particularly limited in this embodiment.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the elongation of the insulating layer 14 in the width direction b is greater than or equal to 10%.

By applying a tensile force in the width direction b to the insulating layer 14 until the insulating layer 14 is broken by not receiving the tensile force, the percentage value of the tensile deformation portion of the insulating layer 14 in the width direction b to the original length is the elongation of the insulating layer 14 in the width direction b.

Since the electrode assembly 10 may undergo swelling deformation during use of the battery cell, the insulating layer 14 disposed at the bending region 17 of the electrode assembly 10 should have a certain elongation deformation property. Based on this, by adopting the above-mentioned scheme, it can be ensured that the insulating layer 14 has a sufficient elongation in the width direction b thereof, so as to ensure that the insulating layer 14 can be adaptively deformed along with the electrode assembly 10, thereby ensuring that the utility range of the insulating layer 14 can cover the corresponding region of the pole piece, and ensuring that the insulating layer 14 can form a reliable insulating barrier utility for dendrites grown from the defect of the separator 13.

Referring to fig. 6, 7 and 8, in some embodiments of the present application, the shrinkage of the insulating layer 14 is 0-3% at 105 ℃.

By comparing the shrinkage of the "dimension of the insulating layer 14 at 105" with the "dimension of the insulating layer 14 at normal temperature", the shrinkage of the insulating layer 14 at 105 "can be obtained.

Since the internal temperature of the battery cell gradually increases with the extension of the service time of the battery cell during the service of the battery cell, the insulation layer 14 may shrink and deform, and if the shrinkage degree is too large, the utility range of the insulation layer 14 may not cover the corresponding area of the full pole piece. Based on this, through adopting above-mentioned scheme, can guarantee that insulating layer 14 is less along with the size shrink degree that battery monomer inside temperature took place during the battery monomer use to can ensure that insulating layer 14's utility scope can cover the corresponding region of pole piece, can ensure that insulating layer 14 can form reliable insulation separation utility to the dendrite that grows from the defect of diaphragm 13.

Referring to fig. 2, some embodiments of the present application further provide a battery 1, where the battery 1 includes the battery cells provided in the embodiments of the present application.

Through adopting above-mentioned scheme, battery 1 accessible is used the battery monomer that this application embodiment provided, guarantee and extension battery 1's life, guarantee and improve battery 1's safety in utilization.

Referring to fig. 1, some embodiments of the present application further provide an electrical device, where the electrical device includes the battery 1 or the battery cell provided in the embodiments of the present application.

Through adopting above-mentioned scheme, the battery 1 or the battery monomer that the power consumption device accessible provided of this application embodiment are used, guarantee and extension power consumption device's life, guarantee and improve power consumption device's safety in utilization.

The foregoing is merely an alternative embodiment of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the scope of the claims of the present application.

Claims (25)

1. A battery cell, wherein the battery cell comprises at least one electrode assembly comprising a positive electrode sheet, a negative electrode sheet, a separator, an insulating layer and a glue layer;

the positive electrode plate, the diaphragm and the negative electrode plate are laminated and wound, and the electrode assembly is provided with a bending area;

At least one part of the insulating layer and at least one part of the adhesive layer are arranged in the bending area, and the insulating layer is adhered to the positive electrode plate or the negative electrode plate through the adhesive layer; and in the thickness direction of the insulating layer, the projected area of the adhesive layer is smaller than that of the insulating layer.

2. The battery cell of claim 1, wherein the glue layer comprises a plurality of glue bodies, at least a portion of the glue bodies being distributed in an edge region of the insulating layer.

3. The battery cell according to claim 2, wherein the gel is a stripe-shaped gel, a plurality of the gels are disposed at intervals along a width direction of the insulating layer, or a plurality of the gels are disposed at intervals along a length direction of the insulating layer.

4. The battery cell of claim 2, wherein the gel is a bulk gel, at least a portion of the gel being disposed at each corner of the insulating layer.

5. The battery cell of claim 1, wherein the glue layer is an electrolyte resistant hot melt glue.

6. The battery cell according to claim 1, wherein a ratio of a projected area of the adhesive layer to a projected area of the insulating layer in a thickness direction of the insulating layer is 20% to 50%.

7. The battery cell of claim 1, wherein the glue layer has a thickness of 2um to 8um.

8. The battery cell according to any one of claims 1 to 7, wherein at least one of the insulating layers is adhered to the inner side of the cathode sheet at the innermost ring through the adhesive layer in the bending region.

9. The battery cell according to any one of claims 1 to 7, wherein at least one of the insulating layers is bonded to the outer side of the cathode sheet at the innermost ring through the adhesive layer in the bending region.

10. The battery cell according to any one of claims 1 to 7, wherein the bending region is provided with two insulating layers, one of the insulating layers is adhered to the inner side of the cathode sheet at the innermost ring through the adhesive layer, and the other insulating layer is adhered to the outer side of the cathode sheet at the innermost ring through the adhesive layer.

11. The battery cell according to any one of claims 1 to 7, wherein the electrode assembly has a body region and a bent region disposed at an end side of the body region; the insulating layer is provided with a bending section which is bent and arranged in the bending area, and an extension section which is connected with the end part of the bending section and is arranged in the main body area.

12. The battery cell according to any one of claims 1-7, wherein the insulating layer is provided with a plurality of holes.

13. The battery cell of claim 12, wherein an absolute value of a difference in porosity of the insulating layer and porosity of the separator is less than or equal to 25%.

14. The battery cell of claim 13, wherein an absolute value of a difference in porosity of the insulating layer and porosity of the separator is less than or equal to 10%.

15. The battery cell of claim 12, wherein the insulating layer is a polyolefin separator.

16. The battery cell of claim 12, wherein the insulating layer has a porosity of 40% to 50%.

17. The battery cell according to claim 12, wherein the insulating layer has a pore diameter a, and the insulating layer has a thickness B, 24.ltoreq.b/a.ltoreq.400.

18. The battery cell according to claim 17, wherein the aperture a of the aperture of the insulating layer is 0.05um to 0.5um.

19. The battery cell of claim 17, wherein the insulating layer has a thickness B of 12um to 20um.

20. The battery cell according to claim 12, wherein the glue layer is recessed from the hole in a thickness direction of the insulating layer.

21. The battery cell according to any one of claims 1 to 7, wherein the insulating layer has a tensile strength in a width direction thereof of 1000kgf/cm or more ² 。

22. The battery cell according to any one of claims 1 to 7, wherein the insulating layer has an elongation in a width direction thereof of 10% or more.

23. The battery cell of any one of claims 1-7, wherein the insulating layer has a shrinkage of 0-3% at 105 ℃.

24. A battery, wherein the battery comprises the battery cell of any one of claims 1-23.

25. An electrical device, wherein the electrical device comprises the battery of claim 24, or the battery cell of any one of claims 1-23.

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