CN213782213U

CN213782213U - Battery cell structure and battery

Info

Publication number: CN213782213U
Application number: CN202022874692.6U
Authority: CN
Inventors: 蒋合林
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2020-12-02
Filing date: 2020-12-02
Publication date: 2021-07-23
Anticipated expiration: 2030-12-02

Abstract

The utility model relates to an electricity core structure and battery. Wherein, electric core structure includes: a positive pole piece comprising a first positive section comprising a first surface; a negative pole piece comprising a first negative section comprising a second surface opposite the first surface; the isolation film is arranged between the positive pole piece and the negative pole piece; the first positive electrode section, the first negative electrode section and the isolating film between the first positive electrode section and the first negative electrode section form a waistcoat area, and insulating layers are arranged on two side edges of the first surface and/or two side edges of the second surface. Through the utility model discloses under the prerequisite of guaranteeing the regional function of vest, set up the insulating layer at the regional first surface and the second surface edge that first positive pole district section and first negative pole district section are relative of vest, can prevent effectively that the burr at first positive pole district section and first negative pole district section edge from punctureing the short circuit problem that the diaphragm caused, ensure the reliability and the security of battery.

Description

Battery cell structure and battery

Technical Field

The utility model relates to a battery technology field especially relates to electric core structure and battery.

Background

With the continuous progress of science and technology, batteries are more and more widely applied in daily life of people. For example: batteries are required in electric vehicles and electronic products. Taking a lithium ion battery as an example, when the lithium ion battery encounters a fault such as impact or foreign matter needling, the positive and negative pole pieces of the battery cell inside the battery are easy to be short-circuited, the current is rapidly increased, and the active chemical substances inside the battery are easy to produce violent chemical reactions, so that thermal runaway is caused, and the safety problems such as explosion and fire of the battery are caused.

In order to improve the safety of the battery, the battery cell is usually provided with a waistcoat region, and the waistcoat region may be composed of a positive plate (such as an empty aluminum foil) and a negative plate (such as an empty copper foil) which are not coated with active materials and are arranged at the outermost circle of the battery cell, and a separation film sandwiched between the positive plate and the negative plate, wherein the aluminum foil is connected with the positive electrode of the battery cell, and the copper foil is connected with the negative electrode of the battery cell. When the lithium ion battery encounters a collision or a foreign body needling fault and other faults, the positive plate and the negative plate which are not coated with the active material are in contact short circuit preferentially, so that the electric quantity in the battery cell is released rapidly, the heat productivity of the battery cell is mainly on the surface of the battery cell, the thermal runaway in the battery can not be caused, and the safety problems of explosion, fire and the like of the battery are prevented.

However, burrs are easily generated on the edges of the positive and negative electrode plates in the waistcoat region during cutting, and the burrs easily pierce the isolating film in the normal use process of the battery, so that the positive and negative electrode plates are abnormally short-circuited, and the normal use of the battery is influenced.

SUMMERY OF THE UTILITY MODEL

For overcoming the problem that exists among the correlation technique, the utility model provides an electricity core structure and battery.

According to the utility model discloses an aspect provides an electricity core structure, include: a positive pole piece comprising a first positive section comprising a first surface; a negative pole piece comprising a first negative section comprising a second surface opposite the first surface; the isolating film is arranged between the positive pole piece and the negative pole piece; the first positive electrode section, the first negative electrode section and the isolating membrane between the first positive electrode section and the first negative electrode section form a waistcoat area, and insulating layers are arranged on two side edges of the first surface and/or two side edges of the second surface.

In an embodiment, the insulating layer is provided at an end edge of the first surface and/or an end edge of the second surface.

In an embodiment, the waistcoat region is disposed at an outermost layer of the cell structure.

In an embodiment, the positive electrode plate, the isolation film and the negative electrode plate are sequentially stacked and wound from inside to outside, and the waistcoat region is disposed at an outermost circle of the cell structure.

In an embodiment, the waistcoat region is further disposed at an innermost circle of the cell structure.

In an embodiment, the positive electrode plate, the isolation film and the negative electrode plate are all provided with a plurality of pieces, and the positive electrode plate, the isolation film and the negative electrode plate are sequentially stacked one on another.

In one embodiment, the insulating layer is one or more of a ceramic coating, a polyimide coating, a resin coating, a rubber coating, and a glass coating.

In one embodiment, the width of the insulating layer ranges from 5mm to 10 mm.

In one embodiment, the positive electrode plate further comprises a second positive electrode section connected with the first positive electrode section, and a positive electrode material layer is arranged on the second positive electrode section; the negative pole piece further comprises a second negative pole section connected with the first negative pole section, and a negative pole material layer is arranged on the second negative pole section.

In an embodiment, the cell structure further includes: a positive electrode tab connected with the second positive electrode section; a negative tab connected with the second negative segment.

According to a second aspect of the embodiments of the present invention, there is provided a battery, including: the cell structure according to any of the embodiments of the first aspect described above.

The embodiment of the utility model provides a technical scheme can include following beneficial effect: on the premise of ensuring the function of the waistcoat region, the insulating layers are arranged on the edges of the first surface and the second surface of the first positive electrode section and the first negative electrode section of the waistcoat region, which are opposite, so that the short circuit problem caused by the fact that burrs on the edges of the first positive electrode section and the first negative electrode section penetrate through the diaphragm can be effectively prevented, and the reliability and the safety of the battery are ensured.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic diagram illustrating a cell structure according to an exemplary embodiment of the present disclosure.

Fig. 2A is an expanded schematic view of a part of a cell structure according to an exemplary embodiment of the present disclosure.

Fig. 2B is an expanded schematic view of another part of the cell structure according to an exemplary embodiment of the present disclosure.

Fig. 3 is a schematic diagram illustrating a structure of a vest region according to an exemplary embodiment of the present disclosure.

Fig. 4 is a schematic structural diagram of a battery shown in accordance with an exemplary embodiment of the present disclosure.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

Fig. 1 is a schematic diagram illustrating a cell structure according to an exemplary embodiment of the present disclosure. Fig. 2A is an expanded schematic view of a part of a cell structure according to an exemplary embodiment of the present disclosure. Fig. 2B is an expanded schematic view of another part of the cell structure according to an exemplary embodiment of the present disclosure.

The battery cell structure 100 of the embodiment of the present disclosure, as a battery cell inside a battery, may be applied to a terminal device. The terminal equipment can be a mobile phone, a tablet computer, a notebook computer, a personal digital assistant, wearable equipment, a sweeping machine, a balance car and the like.

The cell structure 100 may be a winding cell structure or a stacked cell structure. The battery can be a lithium ion battery or a sodium ion battery. In the following description, a lithium ion battery is taken as an example, but the present disclosure is not limited thereto.

As shown in fig. 1, fig. 2A, and fig. 2B, a cell structure 100 provided in the embodiment of the present disclosure may include a positive electrode tab 10, a negative electrode tab 20, and a separation film 30.

The positive pole piece 10 can include a first positive pole segment 13, the first positive pole segment 13 including a first surface 131 (shown in fig. 3). The negative pole piece 20 includes a first negative section 23, and the first negative section 23 includes a second surface 231 (shown in fig. 3), the second surface 231 being opposite to the first surface 131. The separator 30 is disposed between the positive electrode tab 10 and the negative electrode tab 20. The first positive electrode section 13, the first negative electrode section 23, and the isolation film 30 between the first positive electrode section 13 and the first negative electrode section 23 form a waistcoat region, and the insulating layer 60 is disposed on two side edges of the first surface 131 and/or two side edges of the second surface 231.

The first positive electrode section 13 and the first negative electrode section 23 are not coated with active materials, the first positive electrode section 13 may be an empty aluminum foil, and the first negative electrode section 23 may be an empty copper foil. The first positive pole section 13 is connected to the positive pole of the cell structure, and the first negative pole section 23 is connected to the negative pole of the cell structure.

The waistcoat region is a non-charging and discharging region which is not coated with an active material, when the battery is normally used, the waistcoat region does not participate in the charging and discharging process, when the battery is impacted or subjected to external force such as foreign matter needling, the isolating film 30 between the first positive electrode section 13 and the first negative electrode section 23 is broken under the action of the external force, the first positive electrode section 13 and the first negative electrode section 23 in the waistcoat region serve as electric conductors, the first positive electrode section 13 and the first negative electrode section 23 are in contact short circuit, the electric quantity of the charging and discharging region with the active material in the battery cell structure is rapidly released, the heat productivity of the charging and discharging region is mainly concentrated in the waistcoat region, the thermal runaway of the charging and discharging region in the battery cell is not caused, and the safety problems such as ignition, explosion and the like of the charging and discharging region can be effectively prevented.

In the battery cell structure 100 of the embodiment of the present disclosure, the insulating layer 60 is disposed on two side edges of one surface of the opposite surfaces of the first positive electrode section 13 and the first negative electrode section 23 in the waistcoat region, or the insulating layers 60 are disposed on two side edges of both surfaces of the opposite surfaces, so that a short circuit problem caused by burrs at the edges of the first positive electrode section 13 and the first negative electrode section 23 piercing the isolation film 30 during normal use of the battery can be effectively prevented, and reliability of the battery can be ensured; meanwhile, when the battery is impacted or the foreign body is punctured, an effective waistcoat region A (shown in figure 3) between the insulating layers 60 can be preferentially contacted with a short circuit, so that the electric quantity in the battery core is rapidly released, the battery is prevented from exploding and igniting, and the reliability of the battery is improved on the premise of ensuring the function of the waistcoat region.

In some embodiments, the positive electrode tab 10 may include a first positive electrode section 13 and a second positive electrode section 11 connected to the first positive electrode section 13. Wherein the second positive electrode segment 11 is a positive electrode current collector, and the surface thereof is coated with a positive electrode material layer 12. For example, both surfaces of the second positive electrode segment 11 may be coated with the positive electrode material layer 12 at the same time to improve the energy density of the battery cell. The surface of the first positive electrode section 13 is not coated with the positive electrode material layer 12, i.e. the second positive electrode section 11 is a blank electrode sheet and is only used as a conductive electrode sheet. The first positive electrode section 13 and the second positive electrode section 11 may be integrally formed.

The material of the positive electrode plate 10 may be any one of aluminum foil, stainless steel, platinum, gold, titanium, and aluminum alloy. The positive electrode plate 10 of this embodiment is an aluminum foil. The positive electrode material layer 12 as an active material may be a lithium oxide compound such as lithium cobaltate, lithium nickelate, lithium manganate, lithium cobalt nickel manganate, lithium nickel cobalt aluminate.

The negative pole piece 20 may include a first negative section 23 and a second negative section 21 connected to the first negative section 23. Wherein the second negative electrode segment 21 is a negative electrode current collector coated with a negative electrode material layer 22 on the surface thereof, for example, the second negative electrode segment 21 may be coated with the negative electrode material layer 22 on both surfaces thereof to improve the energy density of the battery cell. The surface of the first negative electrode section 23 is not coated with the negative electrode material layer 22, i.e. the first negative electrode section 23 is a blank electrode sheet and only serves as a conductive electrode sheet.

The material of the negative electrode plate 20 may be any one of copper foil, stainless steel, platinum, gold, titanium, and aluminum alloy. The negative electrode plate 20 of this embodiment is a copper foil. The negative electrode material layer 22 as an active material may be a carbon material such as graphite, graphitized carbon, graphene, carbon black, and coke.

A separator 30 is disposed between the positive electrode tab 10 and the negative electrode tab 20 for preventing a short circuit between the positive electrode material layer 12 on the second positive electrode segment 11 and the negative electrode material layer 22 on the second negative electrode segment 21, and preventing a short circuit between the first positive electrode segment 13 and the first negative electrode segment 23.

The separator 30 may be made of a polymer having a porous structure through which lithium ions pass, such as Polyimide (PI), polypropylene (PP), Polyethylene (PE), polyvinyl chloride (PVC), or Polycarbonate (PC).

The second positive electrode section 11 coated with the positive electrode material layer 12, the second negative electrode section 21 coated with the negative electrode material layer 22, and the separation film 30 disposed between the second positive electrode section 11 and the second negative electrode section 21 form a charge and discharge region of the cell structure 100, through which the input and output of the cell current are realized.

In some embodiments, as shown in fig. 2B and 3, the first positive segment 13 may include a first surface 131, the first surface 131 being a face of the first positive segment 13 opposite the first negative segment 23. The first surface 131 has two side edges 132 and an end edge 133, and the two side edges 132 and the end edge 133 surround the periphery of the first positive electrode section 13.

As shown in fig. 2A and 3, the first negative electrode segment 23 may include a second surface 231, and the second surface 231 may also include two side edges (not shown) and an end edge (not shown) as the first surface 131.

In one example, the insulating layer 60 may be disposed at both side edges 132 of the first surface 131 of the first positive electrode section 13, and the insulating layer is not disposed at both side edges of the second surface 231 of the first negative electrode section 23. After the burrs at the both side edges 132 of the first surface 131 or the burrs at the both side edges of the second surface 231 pierce the separation film 30, the first positive electrode section 13 and the first negative electrode section 23 are prevented from contacting a short circuit by the insulating layer on the both side edges 132 of the first surface 131.

In another example, the insulating layers 60 may be disposed at both side edges of the second surface 231 of the first negative electrode section 23, and the insulating layers are not disposed at both side edges of the first surface 131 of the first positive electrode section 13. After the burrs at both side edges 132 of the first surface 131 or the burrs at both side edges of the second surface 231 pierce the separation film 30, the first positive electrode section 13 and the first negative electrode section 23 are prevented from contacting a short circuit by the insulating layer 60 on both side edges of the second surface 231.

In still another example, the insulating layer 60 may be provided on both side edges 132 of the first surface 131 of the first positive electrode section 13, and the insulating layer 60 may be provided on both side edges of the second surface 231 of the first negative electrode section 23, and after the burrs at both side edges 132 of the first surface 131 or the burrs at both side edges of the second surface 231 pierce the separation film 30, the first positive electrode section 13 and the first negative electrode section 23 are prevented from contacting a short circuit by the insulating layer 60 on both side edges of the first surface 131 and the insulating layer 60 on both side edges of the second surface 231.

Because of the risk that the burrs on the first negative electrode section 23 and the first positive electrode section 13 may pierce the insulating layer 60, compared with the case where the insulating layers 60 are disposed on two side edges of two opposite surfaces of the first negative electrode section 23 and the first positive electrode section 13, the short circuit caused by the burr piercing of the first negative electrode section 23 and the first positive electrode section 13 can be more effectively prevented, and the reliability of the battery is further improved.

The insulating layer 60 may cover the two side edges 132 of the first surface 131 by a fused coating, a spray coating, a vapor deposition coating, an electrochemical process coating, a sol-gel coating, an in-situ reaction coating, or the like.

The insulating layer 60 may be one or more of a ceramic coating, a polyimide coating, a resin coating, a rubber coating, and a glass coating. The material has the characteristics of high hardness and corrosion resistance, the risk that the insulating layer is punctured by burrs can be effectively reduced, and the insulating property of the insulating layer is ensured, so that the insulating reliability of the waistcoat region is improved, and the normal use of the battery is ensured.

This disclosed embodiment adopts ceramic coating, and ceramic coating has wear-resisting, and is corrosion-resistant, high rigidity, and high temperature resistance's characteristics compare in other coatings, on the one hand, because ceramic coating's high rigidity can reduce by a wide margin the risk of being pierced by the burr, and on the other hand, because ceramic coating's high temperature resistant can prevent that the battery when normal use, because the high temperature leads to the risk of insulating layer inefficacy, makes the insulating reliability in vest region promote, ensures battery normal use.

In another embodiment, the insulating layer 60 may be further provided at an end edge 133 of the first surface 131. For example, the insulating layer 60 may be coated, printed, etc. over the end edge 133 of the first surface 131. By disposing the insulating layer 60 on both side edges 132 and the end edge 133 of the first surface 131, the short circuit between the isolation film 30 and the first negative electrode section 23 due to the burr on the periphery of the first positive electrode section 13 can be prevented more completely, and the battery cell can be protected more effectively.

In another embodiment, an insulating layer 60 may be further provided at an end edge of the second surface 231. The first positive electrode segment 13 is prevented from contacting the second negative electrode segment 21 by providing an insulating layer 60 on the edges of both the first positive electrode segment 13 and the first negative electrode segment 23.

However, the present disclosure is not limited thereto, and the insulating layer 60 may be provided on the edge of one of the first positive electrode segment 13 and the first negative electrode segment 23 as long as it is ensured that the burrs of the first positive electrode segment 13 and the first negative electrode segment 23 do not contact and short-circuit with each other after piercing the separator 30.

In one embodiment, the width of the insulating layer 60 is in a range of 5mm to 10mm to cover the edge burrs of the first positive electrode segment 13 and the first negative electrode segment 23.

In one embodiment, the waistcoat region is disposed on the outermost layer of the cell structure 100. The outmost vest of electric core structure 100 is regional, can receive striking or foreign matter acupuncture when the battery, and the inside electric quantity of electric core is fallen in timely release, avoids taking place the battery explosion and catches fire, ensures the security of battery.

In one example, the positive electrode plate 10, the separator 30 and the negative electrode plate 20 are sequentially stacked and wound from inside to outside to form a wound cell structure, and the waistcoat region is disposed at the outermost circle of the cell structure 100.

For example, the positive electrode tab 10, the separator 30 and the negative electrode tab 20 may be wound from the beginning (inner) to the end (outer) counterclockwise or clockwise, wherein the first positive electrode section 13, the first negative electrode section 23 and the separator 30 between the first positive electrode section 13 and the first negative electrode section 23 as the waistcoat region are located at the end, i.e., the outermost circle (shown in fig. 1).

In another example, a waistcoat region is further provided at the innermost circle of the cell structure 100, that is, at the starting end of the winding cell structure, that is, at both the innermost circle and the outermost circle of the winding cell structure. Like this, owing to be heated the fusing in the vest region of outermost circle, lead to releasing under the condition that the electric quantity became invalid, at this moment, the vest region of innermost circle can also play a role, continues to release the inside electric quantity of electricity core, further ensures battery safety.

In yet another example, the positive electrode plate 10, the separator 30, and the negative electrode plate 20 are each provided with a plurality of pieces, and the positive electrode plate 10, the separator 30, and the negative electrode plate 20 are sequentially stacked on one another to form a laminated cell structure, wherein the waistcoat region is located at the outermost layer of the laminated cell structure.

In some embodiments, the cell structure 100 further includes a positive tab 40 and a negative tab 50. A positive electrode tab 40 is connected to the second positive electrode section 11. A negative tab 50 is connected to the second negative section 21. For example, the positive electrode tab 40 and the negative electrode tab 50 may be connected to a protection circuit board of the battery.

As shown in fig. 4, according to another aspect of the embodiments of the present disclosure, there is provided a battery 200 including the cell structure 100 of any embodiment of the first aspect.

For example, the battery 200 includes a casing 210 and a protection circuit board disposed on the casing 210, and the cell structure 100 is disposed in the casing 210, wherein the positive electrode tab 40 and the negative electrode tab 50 of the cell structure 100 are electrically connected to the protection circuit board respectively. Protection circuit board and mainboard connection, mainboard and the interface connection that charges. The charging current input to the battery cell and the power supply current output by the battery cell are adjusted through the protection circuit board.

The housing 210 may be a soft-pack housing, such as a soft-pack bag. The housing 210 may also be a rigid housing 210, such as a metal or plastic housing.

The shape of the housing 210 may be cylindrical, rectangular parallelepiped, square, or the like.

The battery 200 of the embodiment of the disclosure can effectively prevent the short circuit problem caused by the burrs on the electrode plates of the waistcoat region piercing the isolation film in the normal use process of the battery, and can ensure the reliability of the battery; simultaneously when the battery takes place the striking or the foreign matter acupuncture, at effective vest region A (shown in figure 3) between the insulating layer, can the preferential contact short circuit, make the inside electric quantity of electricity core release rapidly, prevent that the battery from exploding to catch fire, be promptly under the prerequisite of guaranteeing the regional function of vest, improved the reliability of battery.

It is understood that the term "plurality" in the present invention means two or more, and other terms are similar. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. The singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms "first," "second," and the like are used to describe various information and that such information should not be limited by these terms. These terms are only used to distinguish one type of information from another and do not denote a particular order or importance. Indeed, the terms "first," "second," and the like are fully interchangeable. For example, the first information may also be referred to as second information, and similarly, the second information may also be referred to as first information, without departing from the scope of the present invention.

It will be further understood that the terms "central," "longitudinal," "lateral," "front," "rear," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the present embodiment and to simplify the description, but do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation.

It will be further understood that, unless otherwise specified, "connected" includes direct connections between the two without the presence of other elements, as well as indirect connections between the two with the presence of other elements.

It is further to be understood that while operations are depicted in the drawings in a particular order, this is not to be understood as requiring that such operations be performed in the particular order shown or in serial order, or that all illustrated operations be performed, to achieve desirable results. In certain environments, multitasking and parallel processing may be advantageous.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A cell structure, comprising:

a positive pole piece comprising a first positive section comprising a first surface;

a negative pole piece comprising a first negative section comprising a second surface opposite the first surface;

the isolating film is arranged between the positive pole piece and the negative pole piece;

the first positive electrode section, the first negative electrode section and the isolating membrane between the first positive electrode section and the first negative electrode section form a waistcoat area, and insulating layers are arranged on two side edges of the first surface and/or two side edges of the second surface.

2. The cell structure of claim 1,

the insulating layer is arranged at the end edge of the first surface and/or the end edge of the second surface.

3. The cell structure of claim 1,

the waistcoat region is disposed on an outermost layer of the cell structure.

4. The cell structure of claim 3,

the positive pole piece, the isolating film and the negative pole piece are sequentially overlapped and wound from inside to outside,

the waistcoat region is arranged at the outermost ring of the battery cell structure.

5. The cell structure of claim 4,

the vest area is further arranged at the innermost circle of the battery cell structure.

6. The cell structure of claim 3,

the positive pole piece, the isolating membrane and the negative pole piece are all provided with a plurality of pieces, and the positive pole piece, the isolating membrane and the negative pole piece are sequentially stacked mutually.

7. The cell structure of claim 1,

the insulating layer is one or more of a ceramic coating, a polyimide coating, a resin coating, a rubber coating and a glass coating.

8. The cell structure of claim 1,

the width range of the insulating layer is 5 mm-10 mm.

9. The cell structure of any of claims 1 to 8,

the positive pole piece further comprises a second positive pole section connected with the first positive pole section, and a positive pole material layer is arranged on the second positive pole section;

the negative pole piece further comprises a second negative pole section connected with the first negative pole section, and a negative pole material layer is arranged on the second negative pole section.

10. The cell structure of claim 9, further comprising:

a positive electrode tab connected with the second positive electrode section;

a negative tab connected with the second negative segment.

11. A battery, comprising:

the cell structure of any of claims 1 to 10.